UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

March 3, 2009

	PC Code:  057901

	DP Barcode: D356654

	

MEMORANDUM

Subject:	Registration Review:  Problem Formulation for Ecological Risk,
Environmental Fate, Endangered Species, and Drinking Water Assessments
for Trichlorfon

To:		Kylie Rothwell, Chemical Review Manager

Tracy Perry, Team Leader

Reregistration Branch

Special Review and Reregistration Division

Office of Pesticide Programs

From:		Melissa Panger, Ph.D., Biologist

		Kristina Garber, Biologist

Environmental Risk Branch 4

		Environmental Fate and Effects Division

		Office of Pesticide Programs

Through:	Elizabeth Behl, Chief

		Environmental Risk Branch 4

		Environmental Fate and Effects Division

		Office of Pesticide Programs

The Environmental Fate and Effects Division (EFED) has completed the
problem formulation (attached) for the ecological risk, environmental
fate, endangered species, and drinking water assessments to be conducted
as part of the Registration Review of the organophosphate insecticide,
trichlorfon (PC Code 057901).  Functioning as the first stage of the
risk assessment process for registration review, this problem
formulation provides an overview of what is currently known about the
environmental fate and ecological effects associated with trichlorfon
and its degradates.  It also describes the preliminary ecological risk
hypothesis and analysis plan for evaluating and characterizing risk to
non-target species and the environment in support of the registration of
trichlorfon. 

  SEQ CHAPTER \h \r 1 

				

Problem Formulation for the 

Environmental Fate, Ecological Risk, Endangered Species, and Drinking
Water Assessments 

in Support of the Registration Review of Trichlorfon

dimethyl2,2,2-trichloro-1-hydroxyethyl-phosphonate (CAS 52-68-6)

Prepared by:

Melissa Panger, Ph.D., Biologist

Kristina Garber, Biologist	U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

R. David Jones, Senior Agronomist

Anita Pease, Senior Biologist

Elizabeth Behl, Branch Chief

	

March 3, 2009

Table of Contents

  TOC \o "1-3" \h \z \u    HYPERLINK \l "_Toc223833876"  1.  Purpose	 
PAGEREF _Toc223833876 \h  4  

  HYPERLINK \l "_Toc223833877"  2.  Problem Formulation	  PAGEREF
_Toc223833877 \h  4  

  HYPERLINK \l "_Toc223833878"  2.1. Nature of Regulatory Action	 
PAGEREF _Toc223833878 \h  4  

  HYPERLINK \l "_Toc223833879"  2.2. Previous Risk Assessments	  PAGEREF
_Toc223833879 \h  4  

  HYPERLINK \l "_Toc223833880"  3. Stressor Source and Distribution	 
PAGEREF _Toc223833880 \h  5  

  HYPERLINK \l "_Toc223833881"  3.1. Mechanism of Action	  PAGEREF
_Toc223833881 \h  6  

  HYPERLINK \l "_Toc223833882"  3.2. Overview of Pesticide Use and Usage
  PAGEREF _Toc223833882 \h  6  

  HYPERLINK \l "_Toc223833883"  3.3. Environmental Fate and Transport	 
PAGEREF _Toc223833883 \h  8  

  HYPERLINK \l "_Toc223833884"  3.3.1. Degradation	  PAGEREF
_Toc223833884 \h  10  

  HYPERLINK \l "_Toc223833885"  3.3.2. Transport	  PAGEREF _Toc223833885
\h  10  

  HYPERLINK \l "_Toc223833886"  3.3.3. Terrestrial Field Dissipation	 
PAGEREF _Toc223833886 \h  11  

  HYPERLINK \l "_Toc223833887"  3.3.4. Bioaccumulation	  PAGEREF
_Toc223833887 \h  11  

  HYPERLINK \l "_Toc223833888"  4.  Receptors	  PAGEREF _Toc223833888 \h
 11  

  HYPERLINK \l "_Toc223833889"  4.1. Effects to Aquatic Organisms	 
PAGEREF _Toc223833889 \h  12  

  HYPERLINK \l "_Toc223833890"  4.2. Effects to Terrestrial Organisms	 
PAGEREF _Toc223833890 \h  16  

  HYPERLINK \l "_Toc223833891"  4.3. Incident Database Review	  PAGEREF
_Toc223833891 \h  18  

  HYPERLINK \l "_Toc223833892"  4.4. Ecosystems Potentially at Risk	 
PAGEREF _Toc223833892 \h  21  

  HYPERLINK \l "_Toc223833893"  5. Assessment Endpoints	  PAGEREF
_Toc223833893 \h  21  

  HYPERLINK \l "_Toc223833894"  6.  Conceptual Model	  PAGEREF
_Toc223833894 \h  21  

  HYPERLINK \l "_Toc223833895"  6.1.  Risk Hypothesis	  PAGEREF
_Toc223833895 \h  22  

  HYPERLINK \l "_Toc223833896"  6.2.  Conceptual Diagram	  PAGEREF
_Toc223833896 \h  22  

  HYPERLINK \l "_Toc223833897"  7.  Analysis Plan	  PAGEREF
_Toc223833897 \h  24  

  HYPERLINK \l "_Toc223833898"  7.1.  Stressors of Concern	  PAGEREF
_Toc223833898 \h  25  

  HYPERLINK \l "_Toc223833899"  7.2.  Measures of Exposure	  PAGEREF
_Toc223833899 \h  25  

  HYPERLINK \l "_Toc223833900"  7.3.  Measures of Effect	  PAGEREF
_Toc223833900 \h  27  

  HYPERLINK \l "_Toc223833901"  7.4. Integration of Exposure and Effects
  PAGEREF _Toc223833901 \h  28  

  HYPERLINK \l "_Toc223833902"  7.5. Deterministic and Probabilistic
Assessment Methods	  PAGEREF _Toc223833902 \h  28  

  HYPERLINK \l "_Toc223833903"  7.6. Endangered Species Assessments	 
PAGEREF _Toc223833903 \h  28  

  HYPERLINK \l "_Toc223833904"  7.7. Drinking Water Assessment	  PAGEREF
_Toc223833904 \h  29  

  HYPERLINK \l "_Toc223833905"  7.8. Preliminary Identification of Data
Gaps	  PAGEREF _Toc223833905 \h  29  

  HYPERLINK \l "_Toc223833906"  7.8.1. Fate	  PAGEREF _Toc223833906 \h 
29  

  HYPERLINK \l "_Toc223833907"  7.8.2. Effects data for Trichlorfon	 
PAGEREF _Toc223833907 \h  33  

  HYPERLINK \l "_Toc223833908"  7.8.3. Effects data for DDVP	  PAGEREF
_Toc223833908 \h  37  

  HYPERLINK \l "_Toc223833909"  8.  References	  PAGEREF _Toc223833909
\h  41  

  HYPERLINK \l "_Toc223833910"  Appendix A.  Submitted Toxicity Data for
Trichlorfon and DDVP.	  PAGEREF _Toc223833910 \h  48  

  HYPERLINK \l "_Toc223833911"  Appendix B. The Risk Quotient Method and
Levels of Concern	  PAGEREF _Toc223833911 \h  65  

  HYPERLINK \l "_Toc223833912"  Appendix C.  Data Call-In Tables	 
PAGEREF _Toc223833912 \h  67  

 1.  Purpose

The purpose of this problem formulation is to provide an understanding
of what is known about the environmental fate and ecological effects of
the registered uses of trichlorfon.  Trichlorfon is an organophosphate
used as an insecticide on golf course turf, home lawns, ornamentals
(flowers, trees and shrubs), and ponds (ornamental and bait fish and
non-food aquatic plants).  This document will provide a plan for
analyzing data relevant to trichlorfon, and for conducting environmental
fate, ecological risk, endangered species and drinking water assessments
for registered trichlorfon uses.  Additionally, this problem formulation
is intended to identify data gaps, uncertainties, and potential
assumptions used to address those uncertainties relative to
characterizing the ecological risk associated with the registered uses
of trichlorfon.  

2.  Problem Formulation

2.1. Nature of Regulatory Action

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA),
all pesticides distributed or sold in the United States generally must
be registered by EPA.  In determining whether a pesticide can be
registered in the U.S., EPA evaluates its safety to non-target species
based on a wide range of environmental and health effects studies.  In
1996, FIFRA was amended by the Food Quality Protection Act, and EPA was
mandated to implement a new program for the periodic review of
pesticides, i.e., registration review (  HYPERLINK
"http://www.epa.gov/oppsrrd1/registration_review/" 
http://www.epa.gov/oppsrrd1/registration_review/ ).  The registration
review program is intended to ensure that, as the ability to assess risk
evolves and as policies and practices change, all registered pesticides
continue to meet the statutory standard of no unreasonable adverse
effects to human health and the environment.  Changes in science, public
policy, and pesticide use practices will occur over time.  Through the
new registration review program, the Agency periodically reevaluates
pesticides to make sure that as change occurs, products in the
marketplace can be used safely. 

As part of the implementation of the new Registration Review program
pursuant to Section 3(g) of the Federal Insecticide, Fungicide and
Rodenticide Act (FIFRA), the Agency is beginning its evaluation of
trichlorfon to determine whether it continues to meet the FIFRA standard
for registration.  This problem formulation for the environmental fate,
ecological risk, endangered species, and drinking water assessment
chapter in support of the registration review will be posted in the
initial docket opening the public phase of the review process.

2.2. Previous Risk Assessments

A national-level ecological risk assessment was completed as part of the
reregistration eligibility decision (RED) for trichlorfon in January
1997 (USEPA 1997).  The Environmental Fate and Effects Division’s
(EFED) science chapter for the RED, which incorporated new data, was
revised in 2000 (USEPA 2000).  An interim Tolerance Reassessment and
Risk Management Decision (TRED) for trichlorfon was conducted in 2001
(USEPA 2001).  The TRED was finalized in July 2006 after the cumulative
human health risk assessment of the organophosphate (OP) class of
pesticides was completed (USEPA 2006b).  

A drinking water assessment was conducted for the TRED. In this
assessment, it was concluded that drinking water risk estimates for
surface and ground waters did not exceed levels of concern, except for
children aged 1-6 obtaining drinking water from surface water sources
(USEPA 2006b).

The ecological risk assessment included in the trichlorfon RED was based
on laboratory fate and ecotoxicological data submitted by the registrant
in support of reregistration and from data in publicly available
literature, and incident reports of adverse effects on non-target
organisms associated with the use of trichlorfon.  The previous
ecological risk assessments considered the parent chemical only (i.e.,
the degradates of toxicological concern were not considered).  The
primary environmental concerns identified in the 1997 and 2000
environmental fate and ecological risk assessments were acute and
chronic risks to birds, mammals, fish, and aquatic invertebrates (USEPA
1997, 2000).  

Based on the results of the TRED, a number of mitigation measures were
recommended to address risks to handlers and workers.  These risk
mitigation measures included the following:  prohibit broadcast
treatment to golf course fairways (permit spot treatment to fairways);
require a 7-day application interval for application to turf and limit
applications to no more than 3 per calendar year; require applicators to
use a truck-drawn spray rig for application to fish ponds over 1 acre;
and prohibit foliar applications to ornamentals (allow only direct soil
spray to base of the plant).  These mitigation measures appear on some,
but not all, of the current trichlorfon labels (see Section 3.2).

An emergency exemption petition (Section 18) ecological risk assessment
for use of trichlorfon on ornamentals (in Kansas) was also completed by
EFED (1996).  The results of the Section 18 assessment indicated that
the proposed use of trichlorfon on ornamentals in Kansas would not
result in risks to non-target organisms.  

EPA reinitiated a formal consultation with the U. S. Fish and Wildlife
Service (USFWS) in 1989 regarding trichlorfon impacts on endangered
species.  This consultation was on selected portions of five previous
“cluster” biological opinions evaluating pesticides for certain
crops (corn, cotton, soybeans, sorghum, wheat, barley, oats and rye),
forestry use pesticides, mosquito larvicides, and rangeland and
pastureland pesticides.  As a result, the USFWS issued a formal
Biological Opinion (USFWS 1989).  The opinion identified 79 aquatic
species (6 amphibians, 41 fish, 6 aquatic invertebrates, and 25 mussels)
and one terrestrial species (a bird) that were classified as “in
jeopardy” from trichlorfon use.

3. Stressor Source and Distribution

Trichlorfon degrades to dichlorvos (DDVP), which is also a pesticide
active ingredient (PC Code: 084001).  DDVP is a registered pesticide
used as an insecticide applied to greenhouses, mushroom houses,
residential areas, and premise treatments in agricultural areas (e.g.
barns and sheds) (USEPA 2006a).  Unlike in previous ecological
assessments conducted by the Agency for trichlorfon, the major degradate
DDVP will be considered in the ecological risk assessment conducted as
part of the Registration Review process.  The assessment for
registration review will estimate risk from exposure to trichlorfon, and
its degradate DDVP by evaluating “total trichlorfon residues of
concern” (trichlorfon plus DDVP).  

Although DDVP is a major degradate of trichlorfon, ecological and
endangered species assessments for the trichlorfon registration review
will not evaluate the usage or impact of DDVP as a primary active
ingredient or as a degradate of other pesticide products. While DDVP may
potentially be used simultaneously (for different purposes) within the
same areas as trichlorfon, the use of DDVP will not be addressed in the
ecological and endangered species risk assessments for the trichlorfon
registration review. However, the upcoming drinking water assessment for
the trichlorfon registration review will consider all sources of DDVP,
including direct applications of DDVP as a pesticide active ingredient,
as well as uses of trichlorfon and naled (PC code: 034401), which both
degrade to DDVP.

3.1. Mechanism of Action

Trichlorfon, dimethyl 2,2,2-trichloro-1-hydroxyethyl-phosphonate, is an
insecticide belonging to the organophosphate class of pesticides. 
Organophosphate toxicity is based on the inhibition of the enzyme
acetylcholinesterase, which cleaves the neurotransmitter acetylcholine. 
Inhibition of acetylcholinesterase by organophosphate insecticides
interferes with proper neurotransmission in cholinergic neurosynapses
and neuromuscular junctions.  The trichlorfon degradate DDVP has a
similar mode of action.  

3.2. Overview of Pesticide Use and Usage

Trichlorfon was originally registered for use in the United States in
1955. Currently, labeled uses of trichlorfon include turfgrass (golf
courses, recreational turf and residential turf), flowers, shrubs,
trees, and ponds (those that contain bait and/or ornamental fish and/or
non-food aquatic plants).  There are both commercial and residential
uses.  There are currently nine active Section 3 and three Special Local
Needs labels for products containing trichlorfon (  REF _Ref216518424 \h
 \* MERGEFORMAT  Table 1 ).  There are both granular and flowable uses. 
According to the product labels, trichlorfon can be applied by aerial or
ground equipment.  Currently there is only one label that allows for
aerial applications (Dylox 80 SP, EPA reg. no.: 432-1326); all other
labels limit applications to ground equipment.  The maximum single
application rate for trichlorfon is 8.15 lb a.i./acre.  None of the
current labels specify a maximum number of applications allowed per
year.  Some labels specify a minimum 7-day application interval and a
maximum yearly application rate of 24.5 lb a.i./acre (  REF
_Ref216518424 \h  \* MERGEFORMAT  Table 1 ).  The remaining labels do
not specify a minimum application interval or a maximum yearly
application rate.     

At this time, no national level use data have been identified for
trichlorfon. Pesticide use information from the California Department of
Pesticide Regulation (CDPR 2007), include county-level data for various
trichlorfon uses from 2001-2003.  Past uses of trichlorfon in California
include: landscape maintenance, greenhouse, and water areas. 

Table   SEQ Table \* ARABIC  1 . Summary of Current Trichlorfon Labels.

PRODUCT       (% a.i.)/ EPA REG. NO.	USES	APPL. METHOD(S)	MAX. SINGLE
APPL. RATE	MAX YEARLY APPL. RATE/NO. OF APPL.	APPL. INTERVAL
RESTRICTIONS

Dylox 80 Concentrate (80%)/432-1289 	For formulation into end use
products	N/A	N/A	N/A	N/A	Only for formulations into end-use products on
lawns, turf and recreation areas

Dylox 80 SP (80%)/432-1326 	Flowers, shrubs, and trees and recreational
lawns and turf 	Ground

Aerial 	8.15 lb a.i./acre 

Narcissus - 16 oz a.i./1,000 feet of row 	For Narcissus – 1/year

All other use - Not specified	Not specified	- Do not apply directly to
water.

Dylox 80 Turf and Ornamental (80%)/432-1289 	Landscape flowers, shrubs,
trees, and landscape and recreational turf 	Ground 	8.15 lb a.i./acre 

Narcissus - 16 oz a.i./1,000 feet of row (repeat treatments annually)
24.5 lb a.i./acre

No. of ApplicationsNot Specified	7 days	- Do not apply directly to
water.

- Do not apply when average wind speeds are greater than 15 mph

- Apply product using spray nozzles which produce a coarse droplet size 

- Do not apply within 25 ft of lakes, reservoirs, rivers, permanent
streams, marshes, natural ponds, or estuaries.

- Do not apply through any type of chemigation system

- Golf courses: broadcast use is limited to tees and greens; use on
fairways is limited to spot treatments

Dylox 420 SL (37.3%)/432-1464 	Landscape flowers, shrubs, trees, and
landscape and recreational turf; golf course and residential turf	Ground
	7 lb a.i./acre 

Narcissus – 13.8 oz a.i./1,000 feet of row 	24.5 lb a.i./acre 

For Narcissus – 1 application/ year

All other use – No. of applications not specified	7 days

	

Dylox 80 (80%)/ FL03001200

(432-1289)	Commercially-operated aquaculture production systems
containing ornamental fish or non-food aquatic plants	Hand-held sprayer
(systems less than 1 acre)

Truck-drawn sprayer (systems greater than 1 acre)	0.25 mg a.i./L	Not
specified 	14-days	None

Dylox 80 (80%)/ AR98000300

(432-1289)	Commercially-operated ponds used for bait fish and ornamental
fish production

aquatic plants	Not specified (limited to ground equipment on Federal
label)

	0.25 mg a.i./L

	Not specified

	Not specified (7-day interval on Federal label)

	None



Dylox 80 (80%)/ MO99000500

(432-1289)







Dylox 6.2 Granular (6.2% trichlorfon)/432-1308 (Bayer Environmental
Science)

Granular	Turfgrass 	Ground	8.10 lb a.i./acre 

	24.5 lb a.i./acre 

Max. no. of applications not secified	7 days

	- Do not apply directly to water

- Golf courses: do not apply within 25 ft of lakes, reservoirs, rivers,
permanent streams, marshes, natural ponds, or estuaries

- Not for use on turf being grown for sale

- Must be watered in after application to move product into root zone

- Golf courses: broadcast use is limited to tees and greens; use on
fairways is limited to spot treatments

The Andersons Tee Time Insecticide with 6.2% Dylox (6.2%
trichlorfon)/9198-110 (the Andersons Lawn Fertilizer Division)

Granular







Dylox Grub Control (6.2%)/432-1394 

Granular	Lawns	Ground

	8.10 lb a.i./acre 

 

	Not specified

	Not specified

	- Do not apply directly to water

- Do not apply near fish pools, ponds, streams or lakes

- Water thoroughly within 24 hrs after applying

Dylox 9.3% Insect Granules (9.3%)/72155-83 

Granular	Lawns (residential use only)







	Dylox Insect Granules (6.2%)/72155-33 

Granular









3.3. Environmental Fate and Transport

The chemical structures of trichlorfon and DDVP are depicted in   REF
_Ref217718148 \h  Figure 1 .  Registrant-submitted data defining the
physical, chemical, fate and transport characteristics associated with
trichlorfon are summarized in   REF _Ref216519778 \h  Table 2 .  As part
of registration review, available fate studies for trichlorfon have been
reevaluated by EPA. The fate and transport of trichlorfon in the
environment is briefly discussed below.

Trichlorfon					DDVP

Figure   SEQ Figure \* ARABIC  1 . Structures of trichlorfon and DDVP.

Table   SEQ Table \* ARABIC  2 . General Chemical and Environmental Fate
Properties of Trichlorfon and DDVP.

Chemical/Fate Property	Trichlorfon

Value (source)	DDVP 

Value (source)

Molecular Weight (MW; g/mol)	257.4

(MRID 00152133)	221.0 

(USEPA 2006a)

Water Solubility (Sol; mg/L; at 25 °C)	1.36x105

(MRID 00152133)	0.15 x105 

(USEPA 2006a)

Vapor Pressure (VP; torr; at 25oC)	3.75-4.5x10-6

(MRID 41535301, 41535302)	1.2x10-2 (@20oC)

(USEPA 2006a)

Henry's Law Constant (H;atm-m3/mol)	8.20-9.84 x10-11 

(*)	2.75 x10-6 

(*)

Octanol-water Partition Coefficient (Log KOW)	0.30

(MRID 00162307)	1.58

(MRID 40798103)

Octanol-air Partition Coefficient (Log KOA)	9.7

(**)	6.1

(**)

Organic carbon normalized partition coefficient (L/kg; KOC)	58.8*

(EPISUITE v. 3.20)	37

(MRID 41354105)

Hydrolysis  half lives (days)

                    	No data available	pH 5: 11.6

pH 7: 5.2

pH 9: 0.88

(MRID 41723101)

Aqueous photolysis half-life (days)	Stable

(MRID 00148975)	10 

(MRID 43326601)

Soil Photolysis half-life (days with 12 h light/12 h dark)	No data
available	0.65

(MRID 43642501)

Aerobic Soil Metabolism half-life (days)	6.4

(MRID 42243601)	0.42

(MRID 41723102)

Anaerobic Soil Metabolism half-life (days)	1.8

(MRID 42243601)	6.2

(MRID 43835701)

Aerobic Aquatic Metabolism half-life (days)	No data available	No data
available

Anaerobic Aquatic Metabolism half-life (days)	No data available	4.5

 

**Estimated using Episuite v. 3.20.



3.3.1. Degradation

No scientifically valid studies are available to describe the
degradation of trichlorfon by hydrolysis. Degradation of DDVP by
hydrolysis is pH dependant.  In a hydrolysis study, DDVP half-lives
decreased with increasing pH, with observed half-lives of 11.6 days, 5.2
days, and 0.88 days, at pH 5, 7 and 9, respectively (MRID 41723101).

In a supplemental aqueous photolysis study, trichlorfon was stable to
photolysis (MRID 00148975). Available aqueous and soil photolysis
studies indicate that DDVP is more susceptible to photodegradation than
trichlorfon, with half-lives of 10 and 0.65 days, respectively (MRIDs
43326601 and 43642501).

In an acceptable aerobic soil metabolism study, trichlorfon had a
half-life of 6.4 days on a sandy loam soil. During this study, 3 major
degradates were observed: dichloroacetic acid (DCA) and
1-hydroxy-2,2-dichlorovinyl phosphate (HDCP) and carbon dioxide. DDVP
was not detected as a degradate in this study (MRID 42243601). In an
aerobic soil metabolism study, DDVP had a half-life of 0.42 days (MRID
41723102). 

In an acceptable anaerobic soil metabolism study conducted with the same
sandy loam soil, trichlorfon had a half-life of 1.8 days. Major
degradates observed during this study included: DCA, HDCP, carbon
dioxide and glyoxylic acid (GA).  DDVP was observed as a minor degradate
(MRID 42243601). In an anaerobic soil metabolism study, DDVP had a
half-life of 6.2 days (MRID 43835701).

3.3.2. Transport 

No scientifically valid studies are available to define the mobility of
trichlorfon in soil. The estimated organic carbon partition coefficient
(Koc) of 58.8 (EPIsuite, v.3.20) suggests that trichlorfon may be mobile
in soil. Based on the results of an acceptable soil TLC study, DDVP is
also mobile, with a Koc of 37 L/kg (MRID 41354105).

Consideration of the vapor pressure (3.75-4.5x10-6 torr; MRIDs 41535301,
41535302) and Henry’s Law constant (8.20-9.84x10-11 atm-m3/mol) of
trichlorfon indicates that it is unlikely to be transported
significantly into the air through volatilization from the treatment
site. In contrast, the vapor pressure (1.58x10-2 torr; EPIsuite v.3.20)
and Henry’s Law constant (3.62x10-7 atm-m3/mol) of DDVP are several
orders of magnitude higher than those of trichlorfon, suggesting that
DDVP may volatilize when it has been formed from trichlorfon. 

In a laboratory volatility study, 84% of trichlorfon residues remained
on the soil to which it was applied 14 days previously.   Volatilized
residues comprised 14% of the total applied, and were identified as
carbon dioxide.  Trichlorfon and DDVP were not identified as volatilized
residues (MRID 40279302).  PRIVATE   tc  \l 2 "Mobility" 

3.3.3. Terrestrial  PRIVATE  Field Dissipation

Two supplemental terrestrial field dissipation studies are available
where trichlorfon was applied to sandy loam soil and to turf in field
lysimeters contained in Ontario and Missouri (MRIDs 47519201 and
45895501, respectively). In the bare soil treatments of both studies,
the majority of the applied residues were detected in the upper 0-6
inches of the test soil, with a half life of 3.1 days in the Ontario
test and 1.9 days in the Missouri test. Carbon dioxide was detected as a
major degradate in the Ontario test and a minor degradate in the
Missouri studies. In both studies, DCA was detected as a major
degradate.  DDVP was detected as a minor degradate in the Ontario study,
but undetected in the Missouri study. The maximum residues detected in
the leachate comprised <0.2% of the applied. 

		3.3.4.  PRIVATE  Bioaccumulation tc  \l 2 "Accumulation" 

The octanol-water partition coefficients of trichlorfon (Log KOW = 0.30;
MRID 00162307) and DDVP (Estimated Log KOW = 0.60; EPIsuite, v.3.20)
indicate that trichlorfon and DDVP are not expected to bioaccumulate in
aquatic ecosystems. 

The estimated Log octanol-air partition coefficients (Log KOA) for
trichlorfon and DDVP (9.7 and 6.1, respectively; EPIsuite, v.3.20) in
combination with their Log KOW suggest that biomagnification of
trichlorfon and DDVP in terrestrial food chains is unlikely (Kelly et
al. 2007).  In addition, biomagnification in terrestrial food chains may
be limited by transformation of trichlorfon and DDVP to less toxic
degradates. 

4.  Receptors

Consistent with the process described in the Overview Document (USEPA
2004), the risk assessment for trichlorfon relies on a surrogate species
approach.  T  SEQ CHAPTER \h \r 1 oxicological data generated from
surrogate test species, which are intended to be representative of broad
taxonomic groups, are used to extrapolate to potential effects on a
variety of species (receptors) included under these taxonomic groupings.
 

Because the trichlorfon degradate DDVP is also a registered pesticide
(PC Code: 084001), data are available to define the toxicity of this
degradate of concern to non-target organisms.  To adequately capture the
risk from trichlorfon use, the toxicity and potential exposure to
non-target animals to trichlorfon and its degradate DDVP will be
considered.  The most sensitive endpoints from the available toxicity
data for trichlorfon and DDVP will be used to quantify risk.

Acute and chronic toxicity data from studies submitted by pesticide
registrants along with the available open literature are used to
evaluate the potential direct and indirect effects of trichlorfon to
aquatic and terrestrial receptors.  This includes toxicity on the
technical grade active ingredient, degradates, and when available,
formulated products (e.g., “Six-Pack” studies).  The open literature
studies are identified through EPA’s ECOTOXicology (ECOTOX) database
(USEPA 2007a), which employs a literature search engine for locating
chemical toxicity data for aquatic life, terrestrial plants, and
wildlife.  The evaluation of both sources of data may also provide
insight into the direct and indirect effects of trichlorfon and its
degradate DDVP on biotic communities from loss of species that are
sensitive to the chemical and from changes in structure and functional
characteristics of the affected communities.  Open literature data from
ECOTOX on trichlorfon are not currently available; however, once
received, they will be evaluated for possible quantitative and/or
qualitative inclusion in this risk assessment.    

A summary of the most sensitive data representing non-target organisms
exposed to trichlorfon and DDVP in aquatic and terrestrial habitats is
provided in Sections 4.1 and 4.2, respectively.  A summary of ecological
incidents associated with trichlorfon and DDVP and a description of
ecosystems potentially at risk are provided in Sections 4.3 and 4.4,
respectively. 

4.1. Effects to Aquatic Organisms

Trichlorfon is classified as very highly toxic to freshwater
invertebrates, highly toxic to freshwater fish, and practically nontoxic
to estuarine/marine invertebrates (Eastern oysters) on an acute exposure
basis.  No acceptable acute data for trichlorfon are available for
estuarine/marine fish.  DDVP is classified as very highly toxic to
freshwater and estuarine/marine invertebrates, highly toxic to
freshwater fish, and moderately toxic to estuarine/marine fish on an
acute exposure basis (  REF _Ref216593375 \h  Table 3 ).  No acceptable
aquatic plant toxicity data are currently available for trichlorfon or
DDVP.  Summaries of the most sensitive acute aquatic toxicity data
available from registrant-submitted studies for trichlorfon and DDVP are
provided in   REF _Ref216520200 \h  Table 4  and in   REF _Ref216520201
\h  Table 5 , respectively.  Additional information on the ecotoxicity
data currently available for trichlorfon and DDVP are provided in
APPENDIX A.

Table   SEQ Table \* ARABIC  3 . Classifications of acute toxicities of
trichlorfon and DDVP to aquatic animals.

TAXON	Trichlorfon	DDVP

Freshwater Invertebrate 	Very highly toxic1	Very highly toxic1

Freshwater Fish	Highly toxic2	Highly toxic2

Marine/Estuarine Invertebrate	Practically non-toxic4	Very highly toxic1

Marine/Estuarine Fish	No data	Moderately toxic3

1LC50<0.1 mg/L

2LC50 0.1 - 1.0 mg/L

3LC50 >1.0 - 10 mg/L

4LC50>100 mg/L



For trichlorfon, chronic effects in aquatic animals include diminished
survival (freshwater and estuarine/marine invertebrates), reproduction
(freshwater fish and estuarine/marine invertebrates), and growth
(estuarine/marine invertebrate).  No acute or chronic data are available
for estuarine/marine fish for trichlorfon.  For DDVP, chronic effects in
aquatic animals include diminished survival (freshwater and
estuarine/marine fish), reproduction (freshwater invertebrates), and
growth (freshwater and estuarine/marine invertebrates and
estuarine/marine fish).  Summaries of the most sensitive chronic aquatic
toxicity data available from registrant-submitted studies for
trichlorfon and DDVP are provided in   REF _Ref216520200 \h  Table 4 
and in   REF _Ref216520201 \h  Table 5 , respectively.  

Based on currently available data, DDVP appears to be more or equally as
toxic to aquatic animals when compared to trichlorfon on both an acute
and chronic exposure basis.  

Table   SEQ Table \* ARABIC  4 . Summary of Submitted Studies for
Aquatic Organisms Exposed to Technical Trichlorfon (Most Sensitive
Endpoints for Each Taxon).

TAXON & SPECIES	ENDPOINT	MRID	STUDY CLASS-IFICATION	COMMENTS

Freshwater Invertebrate (Acute) 

Pteronarcella badia	EC50 (96-hr) = 5.3 µg a.i./L

	40098001	Supplemental	Adequate for RQ calculation; based on analysis of
raw data, the slope is 5.2 (C.I.: 2.6 – 7.9)

Freshwater Invertebrate (Chronic)

Daphnia magna	NOAEC = 0.0057 µg a.i./L

	40452601	Acceptable	LOAEC (0.0086 µg a.i./L)

based on survival (all endpoints were affected in the study, the most
sensitive was survival)

Freshwater Fish (Acute) 

Rainbow trout

(Oncorhynchus mykiss)	LC50 (96-hr) = 158 µg a.i./L

	40098001	Supplemental	Adequate for RQ calculation (reported as 156 in
the M&E volume); no slope could be calculated

Freshwater Fish (Chronic) 

Rainbow trout

(Oncorhynchus mykiss)	NOAEC = 110 µg a.i./L

	425717-01	Acceptable	Early life-stage study; LOAEC  (234 µg a.i./L) 
based on increased time to swim up 

Estuarine/ Marine Invertebrate (Acute)

Eastern oyster (Crassostrea virginica)	EC50 >114 mg a.i./L

	444992-01	Acceptable	96-hr shell-deposition study; NOAEC = 83 mg a.i./L
(based on 16% decrease in shell deposition)

Estuarine/ Marine Invertebrate (Chronic)

Mysid (Mysidopsis bahia)	NOAEC = 3.1 µg a.i./L

	444992-02	Acceptable	Flow-through, life-cycle study; LOAEC (234 µg
a.i./L)

based on decreased number of neonates produced, decreased survival,
decreased weight, and decreased length

Estuarine/

Marine Fish 	No acute or chronic exposure data available 

Aquatic Non-Vascular and Vascular Plants	No data available



Table   SEQ Table \* ARABIC  5 . Summary of Submitted Studies for
Aquatic Organisms Exposed to Technical DDVP (Most Sensitive Endpoints
for Each Taxon).

TAXON & SPECIES	ENDPOINT	MRID	STUDY CLASS-IFICATION	COMMENTS

Freshwater Invertebrates (Acute)

Water flea (Daphnia pulex)	EC50 = 0.066 µg a.i./L

	40098001	Acceptable	None

Freshwater Invertebrates (Chronic)

Water flea (Daphnia magna)	NOAEC = 0.0058 µg a.i./L

	43890301	Acceptable	LOAEC (0.0122 µg a.i./L) based on reduced egg
production and growth (length and weight)

Freshwater Fish (Acute)

Cutthroat trout (Oncorhynchus clarki)	LC50 = 170 µg a.i./L

	40098001	Acceptable	None

Freshwater Fish (Chronic)

Rainbow trout (Oncorhynchus mykiss)	NOAEC = 5.2 µg a.i./L

	43788001	Acceptable	LOAEC (10.1 µg a.i./L)

based on decreased post-hatch larval survival

Estuarine/ Marine Invertebrates (Acute)

Mysid (Americamysis bahia)	EC50 = 19.1 µg a.i./L

	43571408	Acceptable	None

Estuarine/ Marine Invertebrates (Chronic) 

Mysid (Americamysis bahia)	NOAEC = 1.48 µg a.i./L

	43854301	Acceptable	LOAEC (3.25 µg a.i./L)

based on reduced growth (weight and length)

Estuarine/ Marine Fish (Acute)

Sheepshead minnow (Cyprinodon variegates)	LC50 = 7,350 µg a.i./L

	43571403	Acceptable	None

Estuarine/ Marine Fish (Chronic)

Sheepshead minnow (Cyprinodon variegates)	NOAEC = 960 µg a.i./L

	43790401	Acceptable	LOAEC (1840 µg a.i./L)

based on reduced survival and length

Aquatic Non-Vascular and Vascular Plants 	No acceptable data available



4.2. Effects to Terrestrial Organisms

Trichlorfon is classified as moderately toxic to mammals on an acute
oral basis.  There are currently no acceptable trichlorfon acute oral or
sub-acute dietary toxicity data for birds.  DDVP is classified as very
highly toxic and moderately toxic to birds on an acute oral and
sub-acute dietary exposure basis, respectively, and is classified as
moderately toxic to mammals on an acute oral exposure basis. 
Trichlorfon is practically nontoxic and DDVP is highly toxic to honey
bees on an acute contact exposure basis (  REF _Ref217718442 \h  \*
MERGEFORMAT  Table 6 ).   Available data on the toxicity of trichlorfon
and DDVP to terrestrial organisms are summarized in Table 7 and Table 8,
respectively.

Table   SEQ Table \* ARABIC  6 . Classifications of Acute Toxicities of
Trichlorfon and DDVP to Terrestrial Animals.

TAXON	Trichlorfon	DDVP

Mammals	Moderately toxic1	Moderately toxic1

Birds	No data 	Very highly toxic2

Honey bees	Practically non-toxic3	Highly toxic4

1LD50 51 -500 mg/kg

2LD50 <10 mg/kg

3LD50 >11 µg/bee

4LD50 <2 µg/bee



For trichlorfon, chronic effects in terrestrial animals include
diminished reproduction (birds) and growth (mammals).  For DDVP, chronic
effects in terrestrial animals include diminished reproduction (birds
and mammals) and growth (mammals).   

As with aquatic animals, DDVP appears to be more or equally as toxic to
terrestrial animals when compared to trichlorfon on both an acute and
chronic exposure basis.  

No terrestrial plant data are available for trichlorfon or DDVP.

Table   SEQ Table \* ARABIC  7 . Summary of Submitted Studies for
Terrestrial Animals Exposed to Technical Trichlorfon (Most Sensitive
Endpoints for Each Taxon).

TAXON & SPECIES	ENDPOINT	MRID	STUDY CLASS-IFICATION	COMMENTS

Birds (Acute)	No acceptable acute data available

Birds (Sub-acute)	No acceptable acute data available

Birds (Chronic)

Bobwhite quail (Colinus virginianus)	NOAEC = 9 mg/kg-diet

	43119501	Acceptable	LOAEC (30 mg/kg-diet) based on a decrease in
hatchling survival (no eggshell thickness effects at any level –
highest = 85 ppm); there were 10 mortalties (1 control, 1 at the 8 ppm
conc., and 8 at the 85 ppm conc.)

Mammals (Acute)  

Laboratory rat (Rattus norvegicus)	LD50 = 136 mg a.i./kg-bw	00256446
Acceptable	None

Mammals  (Chronic)

Laboratory rat (Sprague-Dawley)	NOAEC = 500 mg a.i./kg-diet	42228301
Acceptable	LOAEC (1,750 mg a.i./kg-diet)

based on reduced body weight and dilated renal pelvis in F1 males and
females

Terrestrial Invertebrates Honey bee (Apis mellifera)	LD50 = 59.83 µg
a.i./bee (acute contact)	ACC 00036935 (Atkins et al., 1975)	Acceptable
This study involved exposures of honey bees to trichlorfon in a
formulated product. The slope for this study was 2.81.



Table   SEQ Table \* ARABIC  8 . Summary of Submitted Studies for
Terrestrial Animals Exposed to Technical DDVP (Most Sensitive Endpoints
for Each Taxon).

TAXON & SPECIES	ENDPOINT	MRID	STUDY CLASS-IFICATION	COMMENTS

Birds (Acute)

Bobwhite quail (Colinus virginianus)	LD50 = 8.8 mg a.i./kg bw	40818301
Acceptable	None

Birds (Sub-acute)

Ring-necked pheasant (Phasianus colchicus)	LC50 =  568 mg a.i./kg-diet
0022923	Acceptable	None

Birds (Chronic) Mallard duck (Anas platyrhynchos)	NOAEC = 5 mg
a.i./kg-diet

	44233401	Acceptable	LOAEC (15 mg a.i./kg-diet)

based on reduced eggshell thickness, eggs laid, and number of viable
embryos

Mammals (Acute) Laboratory rat (Rattus norvegicus)	LD50 = 56 mg
a.i./kg-bw	0005467	Acceptable	None

Mammals  (Chronic) Laboratory rat (Rattus norvegicus)	NOAEC = 20 mg
a.i./kg-diet

LOAEC = 80 mg a.i./kg-diet	42483901	Acceptable	Based on reduced
fertility and pup weight

Terrestrial Invertebrates Honey bee (Apis mellifera)	LD50 = 0.5 µg
a.i./bee (contact)	00036935	Acceptable	None



4.3. Incident Database Review

A preliminary review on October 20, 2008, of the Ecological Incident
Information System (EIIS, version 2.0) maintained by the Agency’s
Office of Pesticide Programs (OPP) indicates a total of 4 reported
ecological incidents associated with the use of trichlorfon and 5
associated with the use of DDVP (  REF _Ref216520340 \h  Table 9 ).  All
of the trichlorfon incidents occurred between 1973 and 2003.  Three of
the trichlorfon incidents involved aquatic animals (i.e., fish) and one
involved terrestrial animals (i.e., birds) and all were associated with
mortality of the affected animals.  The certainty categories for the
four incidents ranged from possible (two incidents) to probable (two
incidents), and two of the incidents involved registered uses while the
remaining two involved misuses.  Three of the incidents involved
additional chemicals besides trichlorfon.  Trichlorfon residues were
reported in only one of the incident reports (see   REF _Ref216520340 \h
 Table 9 ).  The reported incidents for trichlorfon involved two uses
that are no longer registered (alfalfa and agricultural area) and two
uses that are currently registered (lawn and golf course).  The two
currently registered uses had certainty categories of probable and
possible.

All of the DDVP incidents occurred between 1973 and 1997.  One of the
DDVP incidents involved aquatic animals (i.e., fish) and four involved
terrestrial animals (i.e., birds and mammals).  All of the aquatic
incidents involved mortality while the terrestrial incidents involved
mortality and/or incapacitation with recovery.  The certainty categories
for the five incidents ranged from possible (two incidents) to highly
probable [probable (two incidents); highly probable (one incident)], and
two of the incidents involved registered uses while the legality of use
was undetermined for the remaining three.  Only one of the incidents
involved additional chemicals besides DDVP.  DDVP residues were reported
in one of the incident reports and ChE inhibition (brain) was reported
in another (see   REF _Ref216520340 \h  Table 9 ).  The use site for one
of the reported DDVP incidents was unknown.  The remaining four
incidents involved the following use sites: industrial operation,
agricultural area, building (inside), and apple.

Although incident reports for trichlorfon and DDVP have not been
received by the Agency since 2003 and 1997, respectively, the absence of
reported incidents should not be construed as the absence of incidents. 
Incident reports for non-target organisms typically provide information
on mortality events only.  Reports for other adverse effects, such as
reduced growth or impaired reproduction, are rarely received.  EPA’s
changes in the registrant reporting requirements for incidents in 1998
may also account for the reduced number of reported incidents. 
Registrants are now only required to submit detailed information on
‘major’ incidents.  Minor incidents are generally reported
aggregately and are not included in EIIS.  In addition, there have been
changes in state monitoring efforts due to lack of resources.  However,
the incident data that are available suggest that exposure pathways are
complete and that exposure levels are sufficient to result in
field-observable effects.  

Table   SEQ Table \* ARABIC  9 . Wildlife Incidents from the EIIS
Associated with Trichlorfon or DDVP.

CHEM. NAME	INCIDENT NO.	TAXA INVOLVED	MAGNITUDE	YEAR	LOCATION	USE
LEGALITY OF USE	CERTAINTY CATEGORY	RESIDUES	OTHER CHEMICALS INVOLVED

Trichlorfon	B0000-224	Aquatic animal

	~1,000 fish (carp, sunfish, and catfish)	1973	California

	Alfalfa

	Misuse	Possible

	8.3 – 12 ppb in affected water	Endosulfan  (0.3-0.59 ppb in affected
water)











Toxaphene    (3.5 ppb in affected water)

	I000223-001	Aquatic animal

	~100 dead bluegill sunfish	1992	Indiana	Lawn	Registered use	Probable	No
Isazofos

(5.5 ppb in pond water)

	I008255-010	Terrestrial animal

	2 dead geese	1998	USA

	Agricultural area

	

Registered use	Possible

	No	None

	I014538-013	Aquatic animal

	~1,500 dead fish	2003	Indiana

	Golf course	Misuse (rinsate released into pond)	Possible

	No	Chlorithalonil











Propiconazole

DDVP	B0000-500-31	Aquatic animal

	379 dead fish	1973	Tennessee

	Industrial operation

	Undetermined	Probable

	No	None

	B0000-500-21	Terrestrial animal

	8 dead mallard ducks	1975	USA

	Agricultural area

	Registered use	Highly probable

	No but there was brain ChE inhibition	None

	I002298-001	Terrestrial animal

	5 dead fox pups (captive); 2 incapacitated fox pups (captive)	1995	USA

	Building (inside)

	Registered use	Possible

	No	None

	I003908-011	Terrestrial animal

	2 bluebird chicks	1994	New York

	Apple

	Undetermined	Probable

	No	None

	I019411-016	Terrestrial Animal

	1 debilitated red-tailed hawk	1997	British Columbia, Canada

	Unknown

	Undetermined	Possible

	28 ppm in crop contents	Naled

(73 ppm in crop contents)











Fonofos

(14 ppm in crop contents)



4.4. Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in scope; therefore, it may
not be possible to identify specific ecosystems during the development
of a nation-wide ecological risk assessment.  However, in general terms,
terrestrial ecosystems potentially at risk could include the treated
field and immediately adjacent areas that may receive drift or runoff. 
Areas adjacent to the treated field could include cultivated fields,
fencerows and hedgerows, meadows, fallow fields or grasslands,
woodlands, riparian habitats and other uncultivated areas.  

Aquatic ecosystems potentially at risk (beyond the aquatic use sites)
include water bodies adjacent to, or down stream from, the treated field
and could include impounded bodies such as ponds, lakes and reservoirs,
or flowing waterways such as streams or rivers.  For uses in coastal
areas, aquatic habitat also includes marine ecosystems, including
estuaries.  

5. Assessment Endpoints

Assessment endpoints represent the actual environmental value that is to
be protected, defined by an ecological entity (species, community, or
other entity) and its attribute or characteristics (USEPA 1998).  For
trichlorfon, the ecological entities may include the following:  birds,
mammals, terrestrial-phase amphibians, reptiles, freshwater fish and
invertebrates, aquatic-phase amphibians, estuarine/marine fish and
invertebrates, terrestrial plants, insects, and aquatic plants and
algae.  The attributes for each of these entities may include growth,
reproduction, and survival.  

6.  Conceptual Model

For a pesticide to pose an ecological risk, it must reach ecological
receptors in biologically significant concentrations.  An exposure
pathway is the means by which a pesticide moves in the environment from
a source to an ecological receptor.  For an ecological pathway to be
complete, it must have a source, a release mechanism, an environmental
transport medium, a point of exposure for ecological receptors, and a
feasible route of exposure.

The conceptual model for trichlorfon provides a written description and
visual representation of the predicted relationships among trichlorfon
(and its degradate DDVP), potential routes of exposure, and the
predicted effects for the assessment endpoint.  A conceptual model
consists of two major components: risk hypothesis and a conceptual
diagram (USEPA 1998).

The primary environmental concerns identified in the 1997 and 2000
environmental fate and ecological risk assessments for trichlorfon were
acute and chronic risks to birds, mammals, fish, and aquatic
invertebrates (USEPA 1997, 2000). However, these risks did not include a
consideration of the trichlorfon degradate DDVP.  Based on available
data, DDVP is more or equally as toxic to aquatic and terrestrial
animals when compared to trichlorfon.  Therefore, risks to non-target
species may be greater than previously assumed once DDVP is considered
in the risk assessment process.  Due to the number of data gaps that
currently exist for trichlorfon and DDVP (see Section 7.8), preliminary
RQs for trichlorfon will not be calculated in this problem formulation. 
The Agency believes that calculating RQs for trichlorfon use at this
time would not be informative due to the uncertainties associated with
the current data gaps.        

6.1.  Risk Hypothesis

A risk hypothesis describes the predicted relationship between the
stressor, exposure, and assessment endpoint response.  For trichlorfon,
the following ecological risk hypothesis is being employed for this
ecological risk assessment:

Based on the application methods, mode of action, fate and transport,
and the sensitivity of non-target aquatic and terrestrial species,
trichlorfon residues of concern (including trichlorfon and its degradate
DDVP) have the potential to reduce survival, reproduction, and/or growth
in non-target terrestrial and aquatic organisms when used in accordance
with current trichlorfon labels.  These non-target organisms include
Federally listed threatened and endangered species as well as non-listed
species.

	6.2.  Conceptual Diagram

The environmental fate properties of trichlorfon and DDVP indicate that
runoff, spray drift, volatilization and direct spray represent potential
transport mechanisms of trichlorfon and DDVP to aquatic and terrestrial
habitats where non-target organisms may be exposed.  These transport
mechanisms (i.e., sources) are depicted in the conceptual models below (
 REF _Ref216664583 \h  Figure 2  and   REF _Ref216664584 \h  Figure 3 )
along with the receptors of concern and the potential attribute changes
in the receptors due to exposures of trichlorfon and DDVP.  

 tc "2.  Diagram " \l 3 

 

Figure   SEQ Figure \* ARABIC  2 . Conceptual model for trichlorfon and
DDVP effects on aquatic organisms.

 

Figure   SEQ Figure \* ARABIC  3 . Conceptual model for trichlorfon and
DDVP effects on terrestrial organisms.

7.  Analysis Plan

In order to address the risk hypothesis, the potential for adverse
effects on the environment is estimated.  The use, environmental fate,
and ecological effects of trichlorfon (and DDVP) are characterized and
integrated to assess the risks using a ‘total trichlorfon residues of
concern’ approach.  In this approach, estimated environmental
concentrations (EECs) will be derived for combined trichlorfon and DDVP.
Risk quotients (RQs) will be derived for the total residues of concern
by dividing EECs by the most sensitive endpoint from the available
toxicity data for trichlorfon and DDVP. 

This analysis plan will be revisited and may be revised depending upon
the data available in the open literature and the information submitted
by the public in response to the opening of the Registration Review
docket.

	7.1.  Stressors of Concern

The primary degradate of concern, DDVP, is considered to have attributes
and effects similar to parent trichlorfon.  Thus, DDVP degradate residue
levels will be considered along with trichlorfon residue levels as
‘total trichlorfon residues of concern’ in this assessment, and
model results (exposure estimates) will reflect the predicted fate of
both trichlorfon and DDVP resulting from trichlorfon usage. 

In its ecological risk assessments, the Agency does not routinely
include an evaluation of mixtures of active ingredients, either those
mixtures of multiple active ingredients in product formulations or those
in the applicator’s tank.  In the case of the product formulations of
active ingredients (that is, a registered product containing more than
one active ingredient), each active ingredient is subject to an
individual risk assessment for regulatory decision regarding the active
ingredient on a particular use site.  If effects data are available for
a formulated product containing more than one active ingredient, the
data may be used qualitatively or quantitatively in accordance with the
Agency’s Overview Document and the Services’ Evaluation Memorandum
(USEPA 2004; USFWS/NMFS 2004).     

Available toxicity data for environmental mixtures of trichlorfon with
other pesticides will be presented as part of the ecological risk
assessment.  It is expected that the toxic effect of trichlorfon, in
combination with other pesticides used in the environment, is likely to
be a function of many factors including but not necessarily limited to:
(1) the exposed species, (2) the co-contaminants in the mixture, (3) the
ratio of trichlorfon and co-contaminant concentrations, (4) differences
in the pattern and duration of exposure among contaminants, and (5) the
differential effects of other physical/chemical characteristics of the
receiving waters (e.g. organic matter present in sediment and suspended
water).  Quantitatively predicting the combined effects of all these
variables on mixture toxicity to any given taxa with confidence is
beyond the capabilities of the available data and methodologies. 
However, a qualitative discussion of implications of the available
pesticide mixture effects data on the confidence of risk assessment
conclusions will be addressed as part of the uncertainty analysis.

	7.2.  Measures of Exposure

In order to estimate risks of trichlorfon and DDVP exposures in aquatic
and terrestrial environments, all exposure modeling and resulting risk
conclusions will be made based on the maximum application rates for
turfgrass, flowers, shrubs, trees, and ponds discussed in Section 3.2. 
Measures of exposure are based on aquatic and terrestrial models that
predict estimated environmental concentrations of trichlorfon residues
of concern using maximum labeled application rates and methods, as well
as any mitigation measures specifically indicated on the label (e.g.
spray drift buffers).  The models used to predict aquatic EECs are the
Pesticide Root Zone Model coupled with the Exposure Analysis Model
System (PRZM/EXAMS).  The model used to predict terrestrial EECs on food
items is T-REX.  These models are parameterized using relevant reviewed
registrant-submitted environmental fate data.

PRZM (v3.12.2, May 2005) and EXAMS (v2.98.4.6, April 2005) are screening
simulation models coupled with the input shell pe5.pl (Aug 2007) to
generate daily exposures and 1-in-10 year EECs of trichlorfon residues
of concern that may occur in surface water bodies adjacent to
application sites receiving trichlorfon through runoff and spray drift. 
 PRZM simulates pesticide application, movement and transformation on an
agricultural field and the resultant pesticide loadings to a receiving
water body via runoff, erosion and spray drift.  EXAMS simulates the
fate of the pesticide and resulting concentrations in the water body. 
The standard scenario used for ecological pesticide assessments assumes
application to a 10-hectare agricultural field that drains into an
adjacent 1-hectare water body that is 2 meters deep (20,000 m3 volume)
with no outlet.  PRZM/EXAMS is used to estimate screening-level exposure
of aquatic organisms to trichlorfon residues of concern.  The measure of
exposure for aquatic species is the 1-in-10 year return peak or rolling
mean concentration.  The 1-in-10 year peak is used for estimating acute
exposures of direct effects to aquatic organisms. The 1-in-10-year
60-day mean is used for assessing chronic exposure to fish and
aquatic-phase amphibians. The 1-in-10-year 21-day mean is used for
assessing aquatic invertebrate chronic exposure.

Exposure estimates for terrestrial animals assumed to be in the target
area or in an area exposed to spray drift are derived using the T-REX
model (version 1.3.1, 12/07/2006).    SEQ CHAPTER \h \r 1 This model
incorporates the Kenega nomograph, as modified by Fletcher et al.
(1994), which is based on a large set of actual field residue data. The
upper limit values from the nomograph represent the 95th percentile of
residue values from actual field measurements (Hoerger and Kenega,
1972).  The Fletcher et al. (1994) modifications to the Kenega nomograph
are based on measured field residues from 249 published research papers,
including information on 118 species of plants, 121 pesticides, and 17
chemical classes.  EECs for terrestrial plants inhabiting dry and
wetland areas are derived using TerrPlant (version 1.2.2, 12/26/2006). 
This model uses estimates of pesticides in runoff and in spray drift to
calculate EECs.  EECs are based upon solubility, application rate and
minimum incorporation depth.

Exposure estimates for birds (and, thus, terrestrial-phase amphibians
and reptiles), terrestrial invertebrates, and mammals assumed to be in
the target area or in an area exposed to trichlorfon granules are
derived using the T-REX model (version 1.3.1, 12/07/2006).  T-REX
includes the capability to calculate the LD50 ft-2 risk index values.
Conceptually, an LD50 ft-2 is the amount of a pesticide estimated to
kill 50% of exposed animals in each square foot of applied area. 
Although a square foot does not have defined ecological relevance and
any unit area could be used, risk presumably increases as the number of
LD50s/ft2 increases.  The LD50/ft2 is used to estimate risk for granular
formulations and row, banded, and in-furrow applications.  For
additional information on the LD50 ft-2 risk index, please reference
U.S. EPA (1992).  The LD50 ft-2 is calculated using a toxicity value
(adjusted LD50) and the EEC (mg a.i. ft-2) and is directly compared with
the Agency's levels of concern (LOCs).

The AgDRIFT spray drift model (version 2.01; dated 5/24/2001) is used to
assess exposures of terrestrial organisms to trichlorfon deposited on
terrestrial habitats by spray drift. AgDRIFT will also be used to
determine the appropriate PRZM/EXAMS parameter values for modeling the
percent drift corresponding to the buffers indicated on the label and to
model areas of effect for aquatic and terrestrial taxa. 

Any available monitoring data obtained from the scientific literature or
submitted studies will be used to characterize exposures of trichlorfon
and DDVP to non-target organisms.

	7.3.  Measures of Effect

 

Ecological effects data are used as measures of direct and indirect
effects to biological receptors.  Data are obtained from
registrant-submitted studies or from literature studies identified by
ECOTOX.  The ECOTOX database (USEPA 2007a) provides more ecological
effects data in an attempt to bridge existing data gaps.  ECOTOX is a
source for locating single chemical toxicity data and potential chemical
mixture toxicity data for aquatic life, terrestrial plants, and
wildlife.  ECOTOX was created and is maintained by the USEPA, Office of
Research and Development, and the National Health and Environmental
Effects Research Laboratory's Mid-Continent Ecology Division.

Information on the potential effects of trichlorfon (and DDVP) on
non-target animals is also collected from the Ecological Incident
Information System (EIIS; USEPA 2007b).  The EIIS is a database
containing adverse effect (typically mortality) reports on non-target
organisms where such effects have been associated with the use of
pesticides.   

Where available, sublethal effects observed in both registrant-submitted
and open literature studies will be evaluated qualitatively.  Such
effects may include behavioral changes (e.g., lethargy and changes in
coloration).  Quantitative assessments of risks, though, are limited to
those endpoints that can be directly linked to the Agency’s assessment
endpoints of impaired survival, growth and reproduction.

  SEQ CHAPTER \h \r 1 The assessment of risk for direct effects to
non-target organisms makes the assumption that toxicity of trichlorfon
and DDVP to birds is similar to terrestrial-phase amphibians and
reptiles.  The same assumption is made for fish and aquatic-phase
amphibians. 

The acute measures of effect used for animals in this assessment are the
LD50, LC50 and EC50.  LD stands for "Lethal Dose", and LD50 is the
amount of a material, given all at once, that is estimated to cause the
death of 50% of the test organisms.  LC stands for “Lethal
Concentration” and LC50 is the concentration of a chemical that is
estimated to kill 50% of the test organisms.  EC stands for “Effective
Concentration” and the EC50 is the concentration of a chemical that is
estimated to produce a specific effect in 50% of the test organisms. 
Endpoints for chronic measures of exposure for listed and non-listed
animals are the NOAEL/NOAEC and NOEC.  NOAEL stands for “No
Observed-Adverse-Effect-Level” and refers to the highest tested dose
of a substance that has been reported to have no harmful (adverse)
effects on test organisms.  The NOAEC (i.e.,
“No-Observed-Adverse-Effect-Concentration”) is the highest test
concentration at which none of the observed effects were statistically
different from the control.  The NOEC is the
No-Observed-Effects-Concentration.  For non-listed plants, only acute
exposures are assessed (i.e., EC25 for terrestrial plants and EC50 for
aquatic plants); for listed plants either the NOAEC or EC05 is used.  

	7.4. Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological
effects characterization to determine the potential ecological risk from
the registered uses of trichlorfon and the likelihood of direct and
indirect effects to non-target organisms in aquatic and terrestrial
habitats.  The exposure and toxicity effects data are integrated in
order to evaluate the risks of adverse ecological effects on non-target
species.  For the assessment of trichlorfon risks, the risk quotient
(RQ) method is used to compare exposure and measured toxicity values. 
EECs are divided by acute and chronic toxicity values.  The resulting
RQs are then compared to the Agency’s Levels of Concern (LOCs) (USEPA
2004) (See Appendix B).  These criteria are used to indicate when
trichlorfon’s uses, as directed on the labels, have the potential to
cause adverse direct or indirect effects to non-target organisms.  In
addition, incident data from the EIIS will be considered as part of the
risk characterization.               

	7.5. Deterministic and Probabilistic Assessment Methods

The quantitative assessment of risk will primarily depend on the
deterministic point-estimate based approach described in the risk
assessment.  An effort will be made to further qualitatively describe
risk using probabilistic tools that the Agency has developed.  These
tools have been reviewed by FIFRA Scientific Advisory Panels ( 
HYPERLINK "http://www.epa.gov/scipoly/sap/index.htm" 
http://www.epa.gov/scipoly/sap/index.htm ) and have been deemed as
appropriate means of refining assessments where deterministic approaches
have identified risks.

	7.6. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered
Species Act (ESA), the Agency will evaluate risks to Federally-listed
threatened and/or endangered (listed) species from registered uses of
trichlorfon.  This assessment will be conducted in accordance with the
Overview Document (USEPA 2004), provisions of the ESA, and the
Services’ Endangered Species Consultation Handbook (USFWS/NMFS, 1998).

The assessment of effects associated with the registration of
trichlorfon (and its degradate DDVP) is based on an action area.  The
action area is considered to be the area directly or indirectly affected
by the federal action, as indicated by the exceedance of Agency Levels
of Concern (LOCs) used to evaluate direct or indirect effects.  The
Agency’s approach to defining the action area under the provisions of
the Overview Document (USEPA 2004) considers the results of the risk
assessment process to establish boundaries for that action area with the
understanding that exposures below the Agency’s defined LOCs
constitute a no-effect threshold.   For the purposes of this assessment,
attention will be focused on the footprint of the action (i.e., the area
where trichlorfon application occurs), plus all areas where offsite
transport (i.e., spray drift, runoff, etc.) may result in potential
exposure that exceeds the Agency’s LOCs.  Specific measures of
ecological effect that define the action area for listed species include
any direct and indirect effects and/or potential modification of its
critical habitat, including reduction in survival, growth, and
reproduction as well as the full suite of sublethal effects available in
the effects literature.  Therefore, the action area extends to a point
where environmental exposures are below any measured lethal or sublethal
effect threshold for any biological entity at the whole organism, organ,
tissue, and cellular level of organization.  In situations where it is
not possible to determine the threshold for an observed effect, the
action area is not spatially limited and is assumed to be the entire
United States.

7.7. Drinking Water Assessment

A drinking water assessment will be conducted to support the human
health risk assessment of trichlorfon in registration review. The
drinking water assessment will incorporate model estimates of
trichlorfon residues of concern (including DDVP and parent) in surface
and ground waters.  Concentrations of trichlorfon residues of concern in
surface waters will be estimated using PRZM/EXAMS (see description
above). Ground water estimates of concentrations of trichlorfon residues
of concern will be estimated using the Screening Concentration in Ground
Water (SCI-GROW) model (v.2.3, July 2003).  The drinking water
assessment will also include a summary of available surface and ground
water monitoring data.  

This drinking water assessment will consider all sources of DDVP,
including direct applications of DDVP as a pesticide active ingredient,
as well as uses of trichlorfon and naled (PC code: 034401), which both
degrade to DDVP.

7.8. Preliminary Identification of Data Gaps

		7.8.1. Fate

The environmental fate data requirements for trichlorfon are partially
fulfilled with some data gaps still remaining (  REF _Ref216520486 \h 
Table 10 ).  The data gaps are discussed below. Data Call-In (DCI)
tables for these data gaps are provided in Appendix C.

Table   SEQ Table \* ARABIC  10 . Available environmental fate data for
trichlorfon and remaining data gaps.

Guideline	Description	MRID	Classification	Data Gap?	comments

835.2120	Hydrolysis	00148974	Invalid	Yes	

1It appears that this study reports the same results as MRID 00157859.

2Because trichlorfon is not expected to be volatile, data describing the
photodegradation of trichlorfon in air are not necessary.

3It appears that this study reports the same results as MRID 00157860.

4 Code of Federal Regulations 40 (CFR40 2007) Part 158 Subpart D state
that these data are not required when the Log Kow of a chemical and its
major degradates are <3. Based on a Log octanol-water partition
coefficient of 0.30 (MRID 00162307) for trichlorfon and 0.60 for DDVP,
these data are not required for trichlorfon or DDVP.

835.2240	Photodegradation in water	00148975	Supplemental	Yes

	835.2410	Photodegradation in soil	00148976	Invalid	Yes



	402614011	Invalid



835.2370	Photodegradation in air	none	Not applicable	No2

	835.4100	Aerobic soil metabolism	00098625	Invalid	No



	42243601	Acceptable



835.4200	Anaerobic soil metabolism	00161359	Invalid	No



	40279301	Invalid





42243601	Acceptable



835.4300	Aerobic Aquatic Metabolism	none	Not applicable	Yes

	835.4400	Anaerobic Aquatic Metabolism	none	Not applicable	Yes

	835.1230

835.1240	 Leaching and adsorption/

desorption	00148977	Invalid	Yes



	402614023	Invalid



835.1410	Laboratory Volatility	40279302	Acceptable	No

	835.6100	Terrestrial Field Dissipation	40279303	Invalid	Yes



	42322501	Invalid





45303501	Under review





45895501	Supplemental





47519201	Supplemental



835.6200	Aquatic Field Dissipation	none	Not applicable	Yes

	850.1730	Accumulation in Fish	none	Not applicable	No4

	

Hydrolysis

Acceptable data have not been provided to quantify the hydrolysis of
trichlorfon.  According to Code of Federal Regulations 40 (CFR40 2007)
Part 158 Subpart N (data requirements for pesticides), hydrolysis data
are required for pesticides with terrestrial or aquatic uses. Since
trichlorfon uses are classified as terrestrial and aquatic, acceptable
hydrolysis data for trichlorfon should be submitted to fulfill OPPTS
Guideline 835.2120. These data are used to estimate the degradation of
trichlorfon in aquatic systems and ultimately to derive aquatic EECs
using PRZM/EXAMS. 

In the case that these data are unavailable at the time risk assessments
are conducted, it will be assumed that trichlorfon is stable to
hydrolysis. 

Aqueous Photolysis

Acceptable data have not been provided to quantify the aqueous
photolysis of trichlorfon. According to Code of Federal Regulations 40
(CFR40 2007) Part 158 Subpart N (data requirements for pesticides),
aqueous photolysis data are required for pesticides with terrestrial or
aquatic uses. Although this represents a data gap, EFED does not
recommend that the Agency request these data at this time because the
available supplemental data are sufficient to characterize the
photolysis of trichlorfon in the aquatic environment.

Photolysis on soil

Acceptable data have not been provided to quantify the photolysis of
trichlorfon on soil. According to Code of Federal Regulations 40 (CFR40
2007) Part 158 Subpart N (data requirements for pesticides), soil
photolysis data are required for pesticides with terrestrial or aquatic
uses. Since trichlorfon uses are classified as terrestrial and aquatic,
acceptable soil photolysis data for trichlorfon should be submitted to
fulfill OPPTS Guideline 835.2410. These data are used to characterize
the degradation of trichlorfon in soil.  In the case that these data are
not submitted, it will be assumed that trichlorfon is stable to
photolysis on soil. 

Aerobic and Anaerobic Aquatic Metabolism

Acceptable data have not been provided to quantify the metabolism of
trichlorfon under aerobic and anaerobic aquatic conditions. According to
Code of Federal Regulations 40 (CFR40 2007) Part 158 Subpart D (data
requirements for pesticides), aerobic and anaerobic aquatic metabolism
data are required for pesticides with terrestrial or aquatic uses. Since
trichlorfon uses are classified as terrestrial and aquatic, acceptable
aerobic and anaerobic aquatic metabolism data for trichlorfon should be
submitted to fulfill OPPTS Guidelines 835.4300 and 835.4400. These data
are used to estimate the degradation of trichlorfon in aquatic systems
and ultimately to derive aquatic EECs using PRZM/EXAMS. In the case that
these data are unavailable at the time risk assessments are conducted,
PRZM/EXAMS input parameter guidance default values will be employed to
account for aerobic and anaerobic aquatic metabolism.

Leaching and Adsorption/Desorption

At this time, there are no acceptable studies to quantify the adsorption
and desorption characteristics of trichlorfon in U.S. soils.  EFED
recommends that the Agency request the submission of an acceptable study
under OPPTS Guideline 835.1230 to define Kd and KOC values of
trichlorfon in U.S. soils. In the absence of these data, EFED will
assume that there is no sorption of trichlorfon to soils or organic
matter on the treatment site.  In order to implement this in derivation
of aquatic EECs, a KOC value of 0 will be used to parameterize
PRZM/EXAMS.  Input of a KOC value >0 is expected to result in lower
aquatic EECs. If acceptable data are provided, the uncertainties
associated with this assumption will be reduced.

Terrestrial Field Dissipation

At this time, two supplemental studies are available to describe the
dissipation of trichlorfon under terrestrial field conditions (MRIDs
45895501 and 47519201). An additional study has been submitted and is
currently under review by EFED (MRID 45303501).  At this time, no
acceptable studies have been identified to fulfill the OPPTS Guideline
835.6100.  Although this represents a data gap, EFED does not recommend
that the Agency request these data at this time because the available
supplemental data are sufficient to characterize the terrestrial field
dissipation of trichlorfon. 

Aquatic Field Dissipation

At this time, no acceptable studies are available to describe the
dissipation of trichlorfon under aquatic field conditions.  According to
Code of Federal Regulations 40 (CFR40 2007) Part 158 Subpart D (data
requirements for pesticides), aquatic field dissipation data are
required for pesticides with aquatic uses. Since trichlorfon uses are
classified as aquatic, aquatic field dissipation data for trichlorfon
should be submitted to fulfill OPPTS Guideline 835.6200.

Environmental Chemistry Methods

Independently validated analytical methods for residues in soil and
water (environmental chemistry methods) submitted by the registrant are
used to evaluate analyses described in submitted environmental fate and
ecological effects studies.  Submitted analytical methods are also used
by various Federal, State, Tribal, and local agencies to detect and
monitor residues that are or are suspected to be in environmental
compartments due to outdoor uses and accidental releases.  Therefore,
availability of these analytical methods is necessary in order to
protect human health and the environment from trichlorfon residues in
the environment.  Independent laboratory validations for submitted
analytical methods are necessary to confirm the levels of detection and
quantitation reported in registrant-prepared validations.

Use of trichlorfon may impact surface water quality due to runoff of
rain water and drift of residues.  Therefore, analytical methods for are
necessary for detecting trichlorfon residues in water and in soil or
sediment.

In the absence of independently validated environmental chemistry
methods, submitted environmental fate and ecological effects data may
not be reviewable and entities outside the Agency may lack
chemical-specific methods for analyses in environmental compartments. 
Independently validated environmental chemistry methods will be used to
evaluate the submitted environmental fate and ecological effects data
and will be made available to the public to support monitoring for
trichlorfon residues.

7.8.2. Effects data for Trichlorfon

Although many submissions have been made to provide data on the effects
of trichlorfon to aquatic and terrestrial organisms, several data gaps
still exist (  REF _Ref216520887 \h  \* MERGEFORMAT  

Table 11  -   REF _Ref216520888 \h  \* MERGEFORMAT  Table 13 ).  Data
gaps include the following: avian acute oral toxicity, avian sub-acute
dietary toxicity, estuarine/marine fish acute toxicity, estuarine/marine
invertebrate acute toxicity, estuarine/marine fish early-life stage
toxicity, and terrestrial and aquatic plant toxicity studies. The data
gaps are discussed below. 

Table   SEQ Table \* ARABIC  11 . Available Ecological Effects Data for
Terrestrial Animals Exposed to Trichlorfon and Remaining Data Gaps
(Studies Classified as ‘Invalid’ are Not Included).

Guideline	Description	MRID/

Accession	Classification	Data Gap?	Comments

850.2100	Avian oral toxicity	None	Not applicable	Yes1	1 An acute oral
toxicity study using either a mallard duck or bobwhite quail AND
passerines must be submitted to fulfill this data requirement.

2 Dietary toxicity studies using a waterfowl and an upland game species
must be submitted to fulfill this data requirement.

850.2200	Avian dietary toxicity 	None	Not applicable	Yes2

	850.2300	Avian reproduction	43019501	Acceptable	No



	43019601	Acceptable



850.3020	Honeybee acute contact toxicity	00036935	Acceptable	No

	



Table   SEQ Table \* ARABIC  12 . Available Ecological Effects Data for
Aquatic Animals Exposed to Trichlorfon and Remaining Data Gaps (Studies
Classified as ‘Invalid’ are Not Included).

Guideline	Description	MRID/ Accession	Classification	Data Gap?	comments

850.1075	Freshwater fish – 

Acute toxicity 	40098001	Supplemental	No	1 The new Part 158 data
requirements specify that acute toxicity data are required on one
estuarine/marine mollusk (guideline fulfilled), one estuarine/marine
invertebrate (guideline not fulfilled), and one estuarine/marine fish
(guideline not fulfilled).

2 A saltwater fish early-life stage test (850.1400) is required for
trichlorfon because the acute toxicity value for saltwater fish is < 1
mg/L (using freshwater fish as a surrogate).





65495	Supplemental





91766	Acceptable



850.1075	Saltwater fish – 

Acute toxicity 	None	Not applicable	Yes1

	850.1010	Freshwater invertebrates –

Acute toxicity	40098001	Supplemental	No

	850.1025

850.1035

850.1045

850.1055	Saltwater invertebrates –

Acute toxicity 	444992	Acceptable	Yes1

	850.1300	Freshwater  invertebrate –

 life cycle test	40452601	Acceptable	No

	850.1350	Saltwater invertebrates – 

life cycle test	44499202	Acceptable	No

	850.1400	Freshwater fish – 

early life stage test	42571701	Acceptable	No

	850.1400	Saltwater fish – 

early life stage test	None	Not applicable	Yes2

	850.1500	Fish – 

life cycle test	None	Not applicable	No

	Table   SEQ Table \* ARABIC  13 . Available Ecological Effects Data
for Plants Exposed to Trichlorfon and Remaining Data Gaps (Studies
Classified as ‘Unacceptable’ are Not Included).

Guideline	Description	MRID	Classification	Data Gap?	comments

850.4100	Terrestrial Plant toxicity: Tier I seedling emergence	None	Not
applicable	Yes1	1 The new Part 158 data requirements specify that
toxicity data are required for terrestrial and aquatic plants.

2 Tier II studies will be required if tested terrestrial species exhibit
a 25% or greater detrimental effect in the Tier I study.



850.4225	Terrestrial Plant toxicity: Tier 2 seedling emergence	None	Not
applicable	No2

	850.4150	Terrestrial Plant toxicity: Tier I vegetative vigor	None	Not
applicable	Yes1

	850.4150	Terrestrial Plant toxicity: Tier 2 vegetative vigor	None	Not
applicable	No2

	850.4400	Aquatic Plant Growth: algae	None	Not applicable	Yes1

	850.4400	Aquatic Plant Growth: vascular plants	None	Not applicable	Yes1

	

Avian Acute Oral Toxicity 

No acceptable avian acute oral toxicity data are currently available for
trichlorfon.  The new Part 158 data requirements [40 CFR Part 158 (CFR
40 2007) data requirements for conventional pesticides (72 FR 60934;
USEPA 2007c)] specify that acute avian oral toxicity data be submitted
for either a mallard duck or bobwhite quail AND a passerine species. 
Additionally, there is one possible ecological incident involving birds
(geese) and the use of trichlorfon (I008255-010).  There is also
evidence to indicate that passerines are more sensitive to at least some
OPs when compared to data from upland and game species.  For example,
dimethoate (an OP) is an order of magnitude more toxic to passerines
than to upland/game species (USEPA 2008).  Therefore, an avian oral
toxicity test (OPPTS Guideline 850.2100;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-2100.pdf) is required for either a
mallard duck or bobwhite quail AND a passerine species, as specified in
40 CFR Part 158 (CFR40 2007).  Trichlorfon registrants will need to
submit a passerine study protocol for review by the Agency prior to
initiation of the passerine study.  If oral acute toxicity data are not
submitted for either mallard duck or bobwhite quail AND passerines, EFED
will assume acute risk to birds in its assessment of trichlorfon. 

Avian Sub-Acute Dietary Toxicity 

No acceptable avian sub-acute dietary toxicity data are currently
available for trichlorfon.  The new Part 158 data requirements [40 CFR
Part 158 (CFR 40 2007) data requirements for conventional pesticides (72
FR 60934; USEPA 2007c)] specify that avian dietary toxicity data be
submitted for both a waterfowl and an upland game species.  There are
currently no acceptable acute oral or sub-acute dietary toxicity data
available for trichlorfon.  However, there is one possible ecological
incident involving birds (geese) and the use of trichlorfon
(I008255-010), indicating a potential risk to birds.  Therefore, an
avian dietary toxicity test (OPPTS Guideline 850.2200;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-2200.pdf) is required for both a
waterfowl and an upland game species, as specified in 40 CFR Part 158
(CFR40 2007).  If dietary toxicity data are not submitted for birds,
EFED will assume acute risk to birds in its assessment of trichlorfon. 

Estuarine/Marine Fish Acute Toxicity

Acute toxicity data are not available for estuarine and marine fish.  In
the absence of these data, an acute-to-chronic ratio (ACR) would
normally be derived and the acute toxicity to estuarine and marine fish
would be estimated based on the ACR for freshwater fish.  However, there
are currently no toxicity data (acute or chronic) for estuarine/marine
fish, therefore, an ACR cannot be derived.  In addition, three of the
four reported ecological incidents associated with the use of
trichlorfon have involved fish kills.  Therefore, an estuarine/marine
fish acute toxicity test (OPPTS Guideline 850.1075;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-1075.pdf) is required in order to
fulfill the data requirement.  In the absence of acute toxicity data for
estuarine and marine fish, EFED will assume acute risk to non-listed and
listed species of estuarine and marine fish.

Estuarine/Marine Invertebrate Acute Toxicity

Although, acute toxicity data are available for an estuarine/marine
mollusk, no acute data are currently available for a non-mollusk
estuarine/marine invertebrate.  The new Part 158 data requirements
specify that acute toxicity data are required on one estuarine/marine
mollusk (guideline fulfilled) and one estuarine/marine invertebrate
(guideline not fulfilled).  In the absence of these data, an
acute-to-chronic ratio (ACR) would normally be derived and the acute
toxicity to estuarine/marine invertebrates would be estimated based on
the ACR for freshwater invertebrates.  However, the freshwater
invertebrate data necessary for calculating the ACR are not available. 
Chronic data are not available for the most acutely sensitive freshwater
species (Pteronarcella badia).  Therefore, an estuarine/marine acute
toxicity test (OPPTS Guideline 850.1035;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-1035.pdf) is required in order to
fulfill the data requirement.  In the absence of acute toxicity data for
estuarine and marine invertebrates, EFED will assume acute risk to
non-listed and listed species of estuarine and marine invertebrates.

Chronic Toxicity Studies with Estuarine and Marine Fish

Chronic toxicity data are not available for estuarine and marine fish. 
In the absence of these data, an acute-to-chronic ratio (ACR) would
normally be derived and the chronic toxicity to estuarine and marine
fish would be estimated based on the ACR for freshwater fish.  However,
there are currently no toxicity data (acute or chronic) for
estuarine/marine fish, therefore, an ACR cannot be derived.  Some of the
reported ecological incidents associated with the use of trichlorfon
have involved fish kills.  Therefore, an estuarine/marine fish early
life-stage toxicity test (OPPTS Guideline 850.1400;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-1400.pdf) is required in order to
fulfill the data requirement.  In the absence of chronic toxicity data
for estuarine and marine fish, EFED will assume chronic risk to
non-listed and listed species of estuarine and marine fish.

Terrestrial Plant Toxicity Studies

Toxicity data for terrestrial plants are not available for trichlorfon. 
Based on the 40 CFR Part 158 data requirements, Tier I level seedling
emergence and vegetative vigor terrestrial plant data are required for
all insecticides.  Therefore, this data gap must be filled, and seedling
emergence terrestrial plant data (OPPTS Guideline 850.4100;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-4100.pdf) and vegetative vigor
terrestrial plant data (OPPTS Guideline 850.4150;   HYPERLINK
"http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecologica
l_Effects_Test_Guidelines/Drafts/850-4150.pdf" 
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-4150.pdf ) are required for
trichlorfon at the Tier 1 level.  In the absence of Tier I data, EFED
will assume risk to non-listed and listed terrestrial plants.

Aquatic Plant Studies 

Toxicity data for vascular and non-vascular aquatic plants are not
available.  Based on the 40 CFR Part 158 data requirements, Tier I level
non-target aquatic plant data are required for all insecticides. 
Therefore, this data gap must be filled, and non-target aquatic plant
data for algae and vascular plants (OPPTS Guideline 850.4400;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-4400.pdf) are required for
trichlorfon at the Tier 1 level.  In the absence of Tier I data, EFED
will assume risk to non-listed and listed species of vascular and
non-vascular aquatic plants.

7.8.3. Effects data for DDVP

Although much data has been provided on the effects of DDVP to aquatic
and terrestrial organisms, several data gaps still exist (Tables 14-16).
Data gaps include the following: avian acute oral toxicity, life-cycle
freshwater fish toxicity, and terrestrial and aquatic plant toxicity
studies. The data gaps are discussed below. 

Table   SEQ Table \* ARABIC  14 . Available Ecological Effects Data for
Terrestrial Animals Exposed to DDVP and Remaining Data Gaps (Only
Studies with the most Sensitive Toxicity Endpoints are Reported).

Guideline	Description	MRID/

Accession	Classification	Data Gap?	Comments

850.2100	Avian oral toxicity	40818301	Acceptable	Yes1	1 The new Part 158
data requirements specify that acute avian oral toxicity data be
submitted for either a mallard duck or bobwhite quail AND a passerine
species. An acute oral toxicity study using passerines must be submitted
to fulfill this data requirement.

850.2200	Avian dietary toxicity 	0022923	Acceptable	No

	850.2300	Avian reproduction	44233401	Acceptable	No

	850.3020	Honeybee acute contact toxicity	00036935	Acceptable	No

	

Table   SEQ Table \* ARABIC  15 . Available Ecological Effects Data for
Aquatic Animals Exposed to DDVP and Remaining Data Gaps (Only Studies
with the most Sensitive Toxicity Endpoints are Reported).

Guideline	Description	MRID/ Accession	Classification	Data Gap?	comments

850.1075	Freshwater fish – 

Acute toxicity 	40098001	Acceptable	No	None

850.1075	Saltwater fish – 

Acute toxicity 	43571403	Acceptable	No

	850.1010	Freshwater invertebrates –

Acute toxicity	40098001	Acceptable	No

	850.1025

850.1035

850.1045

850.1055	Saltwater invertebrates –

Acute toxicity 	43571408	Acceptable	No



	43571404	Acceptable	No

	850.1300	Freshwater  invertebrate –

 life cycle test	43890301	Acceptable	No

	850.1350	Saltwater invertebrates – 

life cycle test	43854301	Acceptable	No

	850.1400	Freshwater fish – 

early life stage test	43788001	Acceptable	No

	850.1400	Saltwater fish – 

early life stage test	43790401	Acceptable	No

	850.1500	Fish – 

life cycle test	None	Not applicable	No

	Table   SEQ Table \* ARABIC  16 . Available Ecological Effects Data
for Plants Exposed to DDVP and Remaining Data Gaps (Only Studies with
the most Sensitive Toxicity Endpoints are Reported).

Guideline	Description	MRID	Classification	Data Gap?	comments

850.4100	Terrestrial Plant toxicity: Tier I seedling emergence	None	Not
applicable	Yes1	1  The new Part 158 data requirements specify that
toxicity data are required for terrestrial and aquatic plants 

2 Tier II studies will be required if tested terrestrial species exhibit
a 25% or greater detrimental effect in the Tier I study.



850.4225	Terrestrial Plant toxicity: Tier 2 seedling emergence	None	Not
applicable	No2

	850.4150	Terrestrial Plant toxicity: Tier I vegetative vigor	None	Not
applicable	Yes1

	850.4150	Terrestrial Plant toxicity: Tier 2 vegetative vigor	None	Not
applicable	No2

	850.4400	Aquatic Plant Growth: algae	None	Not applicable	Yes1

	850.4400	Aquatic Plant Growth: vascular plants	None	Not applicable	Yes1

	

Avian Acute Oral Toxicity 

Acceptable acute avian oral toxicity data were submitted for exposures
of bobwhite quail to DDVP; however, data are not available for
passerines, which are required under the new 40 CFR Part 158 (CFR 40
2007) data requirements for conventional pesticides (72 FR 60934; USEPA
2007c).  The new Part 158 data requirements specify that acute avian
oral toxicity data be submitted for either a mallard duck or bobwhite
quail AND a passerine species.  Based on the results of previous
ecological risk assessments for DDVP, risks are expected for non-listed
and listed birds due to acute exposures to DDVP from the use of
trichlorfon.  Additionally, three of the five ecological incidents
associated with DDVP involved birds, including one involving passerines
(bluebirds; I003908-011).  Therefore, an avian oral toxicity test (OPPTS
Guideline 850.2100;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-2100.pdf) is required for passerine
birds, as specified in 40 CFR Part 158 (CFR40 2007).  Trichlorfan
registrants will need to submit a passerine study protocol for review by
the Agency prior to initiation of this study.  If oral acute toxicity
data are not submitted for passerines, EFED will assume acute risk for
passerine species.

Terrestrial Plant Toxicity Studies

Toxicity data for terrestrial plants are not available for DDVP.  Based
on the 40 CFR Part 158 data requirements, Tier I level seedling
emergence and vegetative vigor terrestrial plant data are required for
all insecticides.  Therefore, this data gap must be filled, and seedling
emergence terrestrial plant data (OPPTS Guideline 850.4100;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-4100.pdf) and vegetative vigor
terrestrial plant data (OPPTS Guideline 850.4150;   HYPERLINK
"http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecologica
l_Effects_Test_Guidelines/Drafts/850-4150.pdf" 
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-4150.pdf ) are required for DDVP at
the Tier 1 level.  In the absence of Tier I data, EFED will assume risk
to terrestrial plants.

Aquatic Plant Studies 

Toxicity data for vascular and non-vascular aquatic plants are not
available.  Based on the 40 CFR Part 158 data requirements, Tier I level
non-target aquatic plant data are required for all insecticides. 
Therefore, this data gap must be filled, and non-target aquatic plant
data for algae and vascular plants (OPPTS Guideline 850.4400;
http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological
_Effects_Test_Guidelines/Drafts/850-4400.pdf) are required for
trichlorfon at the Tier 1 level.  In the absence of Tier I data, EFED
will assume risk to both vascular and non-vascular aquatic plants.

8.  References

CDPR. 2007. a. Pesticide Use Reporting. California Environmental
Protection Agency, Department of Pesticide Regulation. Available online
at:   HYPERLINK "http://www.cdpr.ca.gov/docs/sw/surfcont.htm" 
http://www.cdpr.ca.gov/docs/sw/surfcont.htm . (Accessed 5/31/2007).

CFR 40.  2007.  Code of Federal Regulations 40 Parts 150 to 189. 
Protection of the Environment.  U.S. Government Printing Office.

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger.  1994.  Literature
review and evaluation of the EPA food-chain (Kenaga) nomogram, an
instrument for estimating pesticide residues on plants.  Environ. Tox.
Chem. 13:1383-1391.

  SEQ CHAPTER \h \r 1 Hoerger, F. and E. E. Kenaga, 1972. Pesticide
Residues on Plants: Correlation of Representative Data as a Basis for
Estimation of their Magnitude in the Environment. In F. Coulston and F.
Korte, eds., Environmental Quality and Safety: Chemistry, Toxicology,
and Technology, Georg Thieme Publ., Stuttgart, West Germany, pp. 9-28.

U.S. Environmental Protection Agency (USEPA).  1996.  Emergency
Exemption for use of Trichlorfon on Ornamentals in Kansas (PC Code#
057901;  DP Barcode D229695; ID# 96KS0006; Case# 287853; Sponsor: Kansas
Dept. of Agriculture).

USEPA.  1997.  Reregistration Eligibility Decision (RED): Trichlorfon. 
U.S. Environmental Protection Agency, Office of Prevention, Pesticides
and Toxic Substances, Office of Pesticide Programs, Washington DC.
January 1997.

USEPA.  1998.  Guidelines for Ecological Risk Assessment.  Risk
Assessment Forum, Office of Research and Development,  Washington, D.C. 
EPA/630/R-95/002F.  April 1998.   HYPERLINK
"http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759" 
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759  

USEPA.  2000.  Reregistration Eligibility Science Chapter for
Trichlorfon: Fate and Environmental Risk Assessments.  U.S.
Environmental Protection Agency, Office of Prevention, Pesticides and
Toxic Substances, Office of Pesticide Programs, Washington DC. April
2000.

USEPA.  2001.  Report on FQPA Tolerance Reassessment Progress and
Interim Risk Management Decision (TRED) for Trichlorfon.  U.S.
Environmental Protection Agency, Office of Prevention, Pesticides and
Toxic Substances, Office of Pesticide Programs, Washington DC. September
2001.

USEPA. 2002. Guidance for Selecting Input Parameters in Modeling the
Environmental Fate and Transport of Pesticides, Version II. US
Environmental Protection Agency, Washington DC. Online at:
http://www.epa.gov/oppefed1/models water/input_guidance2_28_02.htm.

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the
Office of Pesticide Programs. U.S. Environmental Protection Agency,
Office of Prevention, Pesticides and Toxic Substances, Office of
Pesticide Programs, Washington DC. January 23, 2004.

USEPA.  2006a.  Interim reregistration Eligibility Decision for
Dichlorvos (DDVP).  U.S. Environmental Protection Agency, Office of
Prevention, Pesticides and Toxic Substances, Office of Pesticide
Programs, Washington DC. June 2006.

USEPA.  2006b.  Finalization of Interim Reregistration Eligibility
Decisions (IREDs) and Interim Tolerance Reassessment and Risk Management
Decisions (TREDs) for the Organophosphate Pesticides, and Completion of
Tolerance Reassessment and Reregistration Eligibility Process for
Organophosphate Pesticides.  Office of Prevention, Pesticides and Toxic
Substances, Office of Pesticide Programs, Washington DC. July 31, 2006.

USEPA. 2007a. ECOTOXicology Database.  Office of Research and
Development National Health and Environmental Effects Research
Laboratory’s (NHEERL’s) Mid-Continent Ecology Division (MED).  
HYPERLINK "http://cfpub.epa.gov/ecotox/"  http://cfpub.epa.gov/ecotox/  

USEPA.  2007b.  Ecological Incident Information System.   HYPERLINK
"http://www.epa.gov/espp/consultation/ecorisk-overview.pdf" 
http://www.epa.gov/espp/consultation/ecorisk-overview.pdf 

USEPA. 2007c.  40 CFR Part 158.  Pesticides; Data Requirements for
Conventional Chemicals: Final Rule. 72 FR 60934.  October 26, 2007.

USEPA.  2008.  Risks of dimethoate use to the federally-listed
California red-legged frog (Rana aurora draytonii). U.S. Environmental
Protection Agency, Office of Prevention, Pesticides and Toxic
Substances, Office of Pesticide Programs, Environmental Fate and Effects
Division.  January 31, 2008.  

U.S. Fish and Wildlife Service (USFWS).  1989.  U.S. Fish and Wildlife
Service Biological Opinion on Selected Pesticides: Dated June 14, 1989;
Revised September 14, 1989.  

USFWS and National Marine Fisheries Service (NMFS).  1998.  Endangered
Species Consultation Handbook:  Procedures for Conducting Consultation
and Conference Activities Under Section 7 of the Endangered Species Act.
 Final Draft.  March 1998.

 

SUBMITTED FATE STUDIES:

MRID: 00098625 

Khasawinah, A.M. (1972) The Fate of ^(R)IDylox in Soil: Report No.
32365. (Unpublished study received May 20, 1977 under 3125-210;
submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:230752-S)

MRID: 00148974 

Pither, K.; Johnson, T. (1985) Hydrolysis of Dylox in Sterile Aqueous
Buffer Solutions: Report No. 90113. Unpublished study prepared by Mobay
Chemical Corporation. 16 p.

MRID: 00148975 

Pither, K.; Johnson, T. (1985) Photodecomposition of Dylox in Aqueous
Solution: Report No. 90155. Unpublished study prepared by Mobay Chemical
Corporation. 15 p.

MRID: 00148976 

Pither, K.; Johnson, T. (1985) Photodecomposition of Dylox on a Soil
Surface: Report No.90153. Unpublished study prepared by Mobay Chemical
Corporation. 17 p.

MRID: 00148977

 Lee, S.; Hanna, L. (1985) Leaching Characteristics of Aged Dylox Soil
Residues: Report No. 90154. Unpublished study prepared by Mobay Chemical
Corporation. 13 p.

MRID: 00152133 

Mobay Chemical Corp. (1985) Product Chemistry of Trichlorfon Technical:
Dylox Technical. Unpublished compilation. 22 p.

MRID: 00161359 

Minor, R.; Freeseman, P. (1986) [Carbon 14] Dylox Anaerobic Soil
Metabolism: 93088.Unpublished study prepared by Mobay Corp. 29 p.

MRID: 00162307 

Technology Services Group (1986) [Product Chemistry Data for Technical
Trichlorfon]. Unpublished compilation. 101 p.

MRID: 40261401 

Pither, K. (1987) Photodecomposition of Dylox on a Soil Surface: Report
No. 91700. Unpublished study prepared by Mobay Corp. 35 p.

MRID: 40279301 

Minor, R.; Freeseman, P.; Pfankuche, L. (1987) The Fate of Dylox under
Anaerobic Soil Conditions: Mobay Project ID: 94596. Un- published study
prepared by Mobay Corp. 58 p.

MRID: 40279302 

Ridlen, R. (1987) Volatility of Dylox and Its Degradates from Soil:
Report No. 94598.Unpublished study prepared by Mobay Corp. 40 p.

MRID: 40279303 Loeffler, W. (1987) Dissipation of Dylox in Field Soil:
Laboratory Project ID: DL-8300-86: Dylox Objective No. 8300. Unpublished
study prepared by Chemonics Laboratories. 62 p.

MRID: 40618201

Pack, D.; Fry, C. (1988) Anaerobic Aquatic Metabolism of (Ethyl-1-
?Carbon 14|Naled): Revised Report: Laboratory Project ID MEF-
0012/8809272. Unpublished study prepared by Chevron Chemical Co. 52 p.

MRID: 41354102

Pack, D.; Fry, C. (1988) Supplement to "Anaerobic Aquatic Metabo- lism
of (Ethyl-1-[Carbon - 14]) NALED": Lab Project Number: MEF/
0012/8716931. Unpublished study prepared by Chevron Chemical Co. 3 p.

MRID: 41354105

Pack, D. (1987) Supplement to "Estimation of Soil Adsorption Coefficient
of NALED from TLC Data": Lab Project Number: MEF0051/8716396A.
Unpublished study prepared by Chevron Chemical Co. 4 p.

MRID: 41535301 Sewekow, ?. (1988) Vapor Pressure of Trichlorfon Pure
Active Ingredient: Lab Project Number: 100 128: 87267. Unpublished study
prepared by Mobay Corp. 11 p.

MRID: 41535302 Weber, ?. (1987) Vapor Pressure of Trichorfon Pure Active
Ingredient: Lab Project Number: 681 538: 94641. Unpublished study
prepared by Corp., and Bayer Ag. 7 p.

MRID: 41723101 

Vithala, R. (1990) DDVP--Hydrolysis of ?C 14| DDVP in Aqueous Solu-
tions Buffered at pH 5, 7, and 9: Lab Project Number: 006/006/ 001/89.
Unpublished study prepared by Univ. of Pittsburgh, Center for Hazardous
Materials Research. 141 p.

MRID: 41723102 

Vithala, R. (1990) DDVP--Aerobic Soil Metabolism of ?C 14| DDVP: Lab
Project Number: 006/006/004/89. Unpublished study prepared by Univ. of
Pittsburgh, Center for Hazardous Materials Research. 7 p.

MRID: 42243601 

Ridlen, R.; Pfankuche, L. (1989) Metabolism of ?1-carbon 14| Trichlorfon
in Soil: LabProject Number: 99640. Unpublished study prepared by Mobay
Corp. 66 p.

MRID: 42322501 

Grace, T.; Cain, K. (1990) Dissipation of Trichlorfon in California
Soils: Lab ProjectNumber: DL830089R01: 100160: ML022101. Unpublished
study prepared by Plant Sciences, Inc.; NET Atlantic, Inc.; Pace Labs.
3801 p.

MRID: 42445101

Pack, D.; Fry, C. (1988) Naled--Anaerobic Aquatic Metabolism of
?Ethyl-1-carbon 14|Naled--Reivsed Report: Supplemental: Lab Project
Number: MEF-0012/8809272. Unpublished study prepared by Chevron Chemical
Co. 11 p.

MRID: 43326601 

Mobley, S. (1994) Aqueous Photolysis of (carbon 14) DDVP (Dichlorvos) in
Artificial Light: Lab Project Number: 838: 1611. Unpublished study
prepared by PTRL East, Inc. 95 p.

MRID: 43642501 

Misra, B. (1995) Photodegradation of (Carbon-14)-DDVP (Dichlorvos) on
Sandy Loam Soil Under Artificial Sunlight Irradiation: Final Report: Lab
Project Number: ME 9400184. Unpublished study prepared by Pittsburgh
Environmental Research Lab, Inc. 79 p.

MRID: 43835701 

Mobley, S. (1995) Anaerobic Soil Metabolism of (carbon 14)DDVP
(Dichlorvos): Lab Project Number: 882: 1847. Unpublished study prepared
by PTRL East, Inc. 82 p.

45303501 

Kasper, A.; Shadrick, B. (1993) Abbreviated Soil Dissipation of (carbon
14) Trichlorfon on California Soils: Lab Project Number: 92157-B:
DL042102: 105157. Unpublished study prepared by Pan-Agricultural
Laboratories, Inc. 102 p.

MRID: 45895501 

Damon, A.; Lenz, M. (2003) Terrestrial Field Dissipation of (Carbon
14)-TrichlorfonUsing Field Lysimeters--Missouri: Lab Project Number:
110960: 45525: DL022101.Unpublished study prepared by Analytical
Bio-Chemistry and Bayer CropScience. 82 p.

MRID: 47519201 

Damon, A.; Lenz, M. (2002) Terrestrial Field Dissipation of 14
C-Trichlorfon Using Field Lysimeters - Ontario. Project Number: 111049.
Unpublished study prepared by ABC Laboratories, Inc. and Bayer
Corporation. 123 p.

SUBMITTED EFFECTS STUDIES:

ECOTOX Reference Number: 000347-69

Hill, E.F., et al.  1975.  Lethal Dietary Toxicities of Environmental
Pollutants to Birds.  U.S. Department of the Interior, Fish and Wildlife
Service, Special Scientific Report – Wildlife No. 191.  Washington,
D.C.

MRID:  43019601

Pedersen, C.; Thompson, S.; Lesar, C. (1993) Effects of DYLOX Technical
on Mallard Duck Reproduction: Lab Project Number: 101/006/08: DL740801:
106226.  Unpublished study prepared by Bio-Life Associates, Ltd. and
Miles Inc. Agricultural Division. 261 p.

MRID:  43119501

Pedersen, C.; Thompson, S. (1994) Effect of DYLOX Technical on Bobwhite
Quail Reproduction: Lab Project Number: 101/005/07: DI741701: 106409. 
Unpublished study prepared by Bio-Life Associates, Ltd. and Miles
Agricultural Division.  301 p. 

ACCESSTION NO.: AC0023

Clinch, P.G. (1967).  The residual contact toxicity to honey bees of
insecticides sprayed on to white clover (Trifolium repens) in the
laboratory.  New Zealand Journal of Agricultural Research,
10(2):289-300.

ACCESSTION NO.: AC0008

Clinch, P.G. (1969).  Laboratory determination of the residual fumigant
toxicity to honey bees of insecticide sprays on white clover (Trifolium
repens). New Zealand Journal of Agricultural Research, 12(1):162-170.

ACCESSTION NO.: AA0Q01

Bartlett, B.R. (1966).  Toxicity and acceptance of some pesticides fed
to parasitic Hymenoptera and predatory coccinellids.  Journal of
Economic Entomology, 59(5):1142-1149.

ACCESSTION NO.: 00001949

Johansen, C.; Eves, J. (1969).  Bee research investigations, 1969:
Small-scale bee poisoning tests with honey bees (HB) and alfalfa
leafcutter bees (LB).  Unpublished study received Sept. 15, 1971 under
1F1032; prepared by Washington State Univ., submitted by Hercules, Inc.,
Wilmington, Del.; CDL:091917-H.

ACCESSTION NO.: 00060628

Johansen, C.; Eves, J. (1969).  Bee poisoning investigations, 1965:
Report No. G-1705; Report No. 17338.  Unpublished study, including
letter dated June 12, 1973 from C.A. Johansen to A.D. Cohick, received
Mar 27, 1974 under 4F1485; prepared by Washington State Univ., Dept. of
Entomology, submitted by Chemagro Corp., Kansas City, MO.; CDL:092011-I.

ACCESSTION NO.: 00036935

Atkins, E.L.; E.A. Greywood; R.L. MacDonald (1975).  Toxicity of
pesticides and other agricultural chemicals to honey bees.  Laboratory
studies.  Univ. of Californis, Division of Agricultural Science. 
Leaflet 2287.  38 pp.

ACCESSTION NO.: 05008149

Gholson, L.E.; C.C. Beegle; R.L. Best; J.C. Owens (1978).  Effects of
several commonly-used insecticides on cornfield carabids in Iowa.  J.
Econ. Entomol., 71(3):416-418.

MRID:  40098001

Mayer, F.; Ellersieck, M. (1986) Manual of Acute Toxicity:
Interpretation and Data Base 410 Chemicals and 66 Species of Fresh-Water
Animals. US Fish & Wildlife Service; Resource Publica tion (160): 579 p.

MRID:  404526-01

Forbis, A.D.  (1987).  Chronic Toxicity of 14C-DYLOX® to Daphnia magna
Under Flow-Through Test Conditions.    SEQ CHAPTER \h \r 1 Unpublished
study performed by Analytical Bio-Chemistry Laboratories, Inc.,
Columbia, MO.  Laboratory Final Report No. 35738.  Study sponsored by
Mobay Corporation, Stilwell, KS.  Study initiated June 15, 1987 and
completed July 6, 1987.  

 

MRID:  65495

Pickering, Q.H., C. Henderson and A.E. Lemke.  1981.  The Toxicity of
Organic Phosphorous Insecticides to Different Species of Warm Water
Fishes.  U.S. Department of Health, Education and Welfare.  Public
Health Service.  R.A. Taft Sanitary Engineering Center, Cincinnati,
Ohio.

MRID:  42571701

Gagliano, G. (1992) Early Life Stage Toxicity of Dylox Technical to the
Rainbow Trout (Oncorhynchus mykiss) under Flow-through Conditions: Lab
Project Number: DL842201: 103928: Unpublished study prepared by Miles
Incorporated.  192 p. 

MRID:  44499201

Drottar, K.; Krueger, H. (1998) Trichlorfon (Dylox): A 96-Hour Shell
Deposition Test with the Eastern Oyster (Crassostrea virginica): Lab
Project Number: 149A-105: 108069.  Unpublished study prepared by
Wildlife International Ltd.  43 p. 

MRID:  44499202

Drottar, K.; Krueger, H. (1998) Trichlorfon (Dylox): A Flow-Through
Life-Cycle Toxicity Test with the Saltwater Mysid (Mysidopsis bahia):
Lab Project Number: 149A-106: 108070. Unpublished study prepared by
Wildlife International Ltd.  55 p.  Relates to L0000302. 

MRID:  42228301

Eigenberg, D. (1991) A Two-Generation Dietary Reproduction Study in Rats
Using Technical Grade Trichlorfon (Dylox): Lab Project Number:
89-672-EA. Unpublished study prepared by Mobay Corp. 1075 p. 

MRID:  40818301

Grimes, J.; Jaber, M. (1988) DDVP: An Acute Oral Toxicity Study with the
Bobwhite: Final Report: Project No. 246-102. Unpub- lished study
prepared by Wildlife International Ltd. 21 p. 

MRID:  22923

Hill, E.F.; Heath, R.G.; Spann, J.W.; et al. (1975) Lethal Dietary
Toxicities of Environmental Pollutants to Birds: Special Scientific
Report--Wildlife No. 191. (U.S. Dept. of the Interior, Fish and Wildlife
Service, Patuxent Wildlife Research Center; unpublished report)

MRID:  44233401

Redgrave, V. (1997) Mallard Duck Dietary Reproduction and Tolerance
Studies: DDVP: Lab Project Number: AVC 7/961821: AVC 7. Unpublished
study prepared by Huntingdon Life Sciences Ltd. 243 p. 

MRID:  5467

Gaines, T.B. (1960) The acute toxicity of pesticides to rats. Toxicology
and Applied Pharmacology 2(1):88-99. (Also in unpublished submission
received Feb 14, 1961 under PP0299; submitted by Chemagro Corp., Kansas
City, Mo.; CDL:090320-Q) 

MRID:  42483901

Tyl, R.; Myers, C.; Marr, M. (1992) Two-Generation Reproductive Toxicity
Study of DDVP Administered in Drinking Water to CD (Sprague-Dawley)
Rats: Final Report: Lab Project Number 60C-4629-170. Unpublished study
prepared by Research Triangle Institute. 1225 p. 

MRID:  43890301

Ward, G.; Davis, J. (1995) DDVP Technical Grade: Chronic Life-Cycle
Toxicity to the Water Flea, Daphnia magna, Under Flow-Through Test
Conditions: Lab Project Number: J94030071: J9403007N. Unpublished study
prepared by Toxikon Environmental Sciences. 74 p. 

MRID:  43788001

Davis, J. (1995) DDVP Technical Grade: Toxicity to Embryos and Larvae of
the Rainbow Trout, Oncorhynchus mykiss, Under Flow-Through Conditions:
Lab Project Number: J9403007M. Unpublished study prepared by Toxikon
Environmental Sciences. 77 p. 

MRID:  43571408

Jones, F.; Davis, J. (1994) DDVP 4-E Emulsifiable Concentrate: Acute
Toxicity to the Mysid, Mysidopsis bahia, Under Flow-through Test
Conditions: Lab Project Numbers: J9403007J: J9403007B. Unpublished study
prepared by Toxikon Environmental Sciences. 60 p. 

MRID:  43854301

Ward, S.; Davis, J. (1995) DDVP Technical Grade: Chronic Toxicity to the
Mysid (Mysidopsis bahia) Under Flow Through Conditions: Lab Project
Number: J9407006A. Unpublished study prepared by Toxikon Environmental
Sciences. 90 p. 

MRID:  43571403

Jones, F.; Davis, J. (1994) DDVP Technical Grade: Acute Toxicity to
Sheepshead Minnow (Cyprinodon variegatus) Under Flow-through Test
Conditions: Lab Project Numbers: J9403007F: J9403007B. Unpublished study
prepared by Toxikon Environmental Sciences. 59 p. 

MRID:  43790401

Ward, G.; Davis, J. (1995) DDVP Technical Grade: Toxicity to Embryos and
Larvae of the Sheepshead Minnow (Cyprinodon variegatus) Under
Flow-Through Test Conditions: Lab Project Number: J9407006B. Unpublished
study prepared by Toxikon Environmental Sciences. 81 p. 

Appendix A.  Submitted Toxicity Data for Trichlorfon and DDVP.

Studies classified as ‘unacceptable’ are excluded.

TABLE A.1.  Submitted Toxicity Data for Trichlorfon (The studies with
the most sensitive endpoint for each taxon are highlighted).

TAXON	ENDPOINT	FORMULATION	MRID	STUDY CLASS-IFICATION	COMMENTS

Birds (Chronic)

Mallard duck (Anas platyrhynchos)	NOAEC = 27 mg/kg-diet

LOAEC = 78 mg/kg-diet	Technical (99.8%)	43019601	Acceptable	Based on
decrease in eggshell thickness (16% reduction compared to control) and
percent viable embryos (i.e., %of eggs set); 4 birds at the 235
concentration died after exhibiting clinical signs of toxicity; 1
control bird died



Bobwhite quail (Colinus virginianus)	NOAEC = 9 mg/kg-diet

LOAEC = 30 mg/kg-diet	Technical (99.8%)	43119501	Acceptable	Based on a
decrease in hatchling survival (no eggshell thickness effects at any
level – highest = 85 ppm); there were 10 mortalties (1 control, 1 at
the 8 ppm concentration, and 8 at the 85 ppm conc.)

Terrestrial Invertebrates

Honey bee (Apis mellifera)	LC50 > 1.20 lb a.i./acre	Formulation (SP,
80%)	AC0023 (Clinch, 1967)	Supplemental	Non-guideline study; insecticide
sprayed from tower – honey bees enclosed with contaminated flowers for
1 hr (3 hrs after spray); no mortalities up to 24-hr after exposure;
only 1 conc. tested.

Honey bee (Apis mellifera)	LC50 > 1.20 lb a.i./acre	Formulation (SP,
80%)	AC0008 (Clinch, 1969)	Supplemental	Non-guideline study; test to
mimic fumigant toxicity; bees exposed for 1 hr; no ‘fumigant
toxicity’ noted for trichlorfon; only 1 conc. tested.

Lady beetle (Lindorus lophanthae)	LC50 > 0.477% a.i. in honey (w/w) =
4,770 ppm (some mortality, specifics not provided except <50%)
Formulation (SP, 50%)	AA0Q01 (Bartlett, 1966)	Supplemental
Non-guideline; dietary study; pesticides mixed into honey bait; bees
allowed to feed for 6 hrs, then held for 4 days; only 2 conc. tested.

Mealybug destroyer (Cryptolaemus montrouzieri)	LC50 > 0.477% a.i. in
honey (w/w) = 4,770 ppm (some mortality, specifics not provided except
<50%)





Scale predator (Aphytis melinus)	LC50 = 0.477% a.i. in honey (w/w) =
4,770 ppm (up to 4-days after exposure)





Parasitic wasp (Metaphycus luteolus)	LC50 = 0.477% a.i. in honey (w/w) =
4,770 ppm (up to 4-days after exposure)





Alfalfa leafcutter bee (Megachile rotundata)	65% mortality (2 lb
a.i./acre application rate) – when exposed to 8-hr old residues	Dylox
SP (80%)	ACC 00001949 (Johansen and Eves, 1969)	Supplemental
Non-guideline; alfalfa treated using hand sprayer, bees were caged on
treated foliage; mortality evaluated 24-hr post exposure; only 1 conc.
tested

Honey bee (Apis mellifera)	44% mortality (2 lb a.i./acre application
rate) – when exposed to 3-hr old residues	Dylox SP (80%)	ACC 00001949
(Johansen and Eves, 1969)	Supplemental	Non-guideline; alfalfa treated
using hand sprayer, bees were caged on treated foliage; mortality
evaluated 24-hr post exposure; only 1 conc. tested

Honey bee (Apis mellifera)	17% mortality (1 lb a.i./acre application
rate) – when exposed to 3-hr old residues; 0% with 2-day old residues
Dylox SP (50%)	ACC 00060628 (Johansen and Eves, 1965)	Supplemental
Non-guideline; alfalfa treated using hand sprayer, bees were caged on
treated foliage; mortality evaluated 48-hr post exposure; only 1 conc.
tested

Alkali bee (Nomia melanderi)	31% mortality (1 lb a.i./acre application
rate) – when exposed to 3-hr old residues; 10% with 2-day old residues
Dylox SP (50%)	ACC 00060628 (Johansen and Eves, 1965)	Supplemental
Non-guideline; alfalfa treated using hand sprayer, bees were caged on
treated foliage; mortality evaluated 48-hr post exposure; only 1 conc.
tested

Leafcutter bee (Megachile rotundata)	5% mortality (1 lb a.i./acre
application rate) – when exposed to 3-hr old residues	Dylox SP (50%)
ACC 00060628 (Johansen and Eves, 1965)	Supplemental	Non-guideline;
alfalfa treated using hand sprayer, bees were caged on treated foliage;
mortality evaluated 48-hr post exposure; only 1 conc. tested

Honey bee (Apis mellifera)	LD50 = 59.83 µg a.i./bee (acute contact);
slope – 2.81	Formulation	ACC 00036935 (Atkins et al., 1975)	Acceptable
A bell-jar vacuum duster was used to apply the pesticide, mixed with
pyrolite dust diluent, to bees; observations up to 96-hrs post treatment

Ground beetle (Scarites substriatus)	100% mortality at 1 lb a.i./acre
Formulation (80%)	ACC 05008149 (Gholson et al., 1978)	Supplemental
Non-guideline; soil surface sprayed with pesticide; beetles placed in
soil and mortality evaluated after 5 days; only 1 conc. tested

Ground beetle (Pterostichus chalcites)	100% mortality at 1 lb a.i./acre
Formulation (80%)	ACC 05008149 (Gholson et al., 1978)	Supplemental
Non-guideline; soil surface sprayed with pesticide; beetles placed in
soil and mortality evaluated after 5 days; only 1 conc. tested

Ground beetle (Bembidion rapidum)	97.5% mortality at 1 lb a.i./acre
Formulation (80%)	ACC 05008149 (Gholson et al., 1978)	Supplemental
Non-guideline; soil surface sprayed with pesticide; beetles placed in
soil and mortality evaluated after 5 days; only 1 conc. tested

Ground beetle (Harpalus pensylvanicus)	50% mortality at 1 lb a.i./acre
Formulation (80%)	ACC 05008149 (Gholson et al., 1978)	Supplemental
Non-guideline; soil surface sprayed with pesticide; beetles placed in
soil and mortality evaluated after 5 days; only 1 conc. tested

Freshwater Invertebrates (Acute)

Daphnia pulex	EC50 (48-hr) = 0.18 µg/L	Technical	40098001	Supplemental
(also reported in 40094602); raw data from M&E not legible

Simocephalus serrulatus	EC50 (48-hr) = 0.70 µg/L	Technical	40098001
Supplemental	(also reported in 40094602); no raw data available

Simocephalus serrulatus	EC50 (48-hr) = 0.32 µg/L	Technical	40098001
Supplemental	No raw data available

Gammarus lacustris	EC50 (96-hr) = 40 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 108 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 275 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 90 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 108 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 119 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = >40 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 43 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 32 µg/L	Technical	40098001
Supplemental

	Gammarus pseudolimnaeus	EC50 (96-hr) = 17 µg/L	80% wettable powder
40098001	Supplemental

	Procambarus sp.	EC50 (96-hr) = 7,800 µg/L	Technical	40098001
Supplemental

	Procambarus sp.	EC50 (96-hr) = 13,300 µg/L	Technical	40098001
Supplemental

	Claassenia sabulosa	EC50 (96-hr) = 22 µg/L	Technical	40098001
Supplemental

	Isogenus sp.	EC50 (96-hr) = 24 µg/L	Technical	40098001	Supplemental

	Isogenus sp.	EC50 (96-hr) = 12 µg/L	80% wettable powder 	40098001
Supplemental

	Pteronarcella badia	EC50 (96-hr) = 11 µg/L	Technical	40098001
Supplemental	Not enough information available in the raw data to confirm
the results

Pteronarcella badia	EC50 (96-hr) = 100 µg/L	Technical	40098001
Supplemental

	Pteronarcella badia	EC50 (96-hr) = 9.8 µg/L	Technical	40098001
Supplemental

	Pteronarcella badia	EC50 (96-hr) = 5.3 µg/L	Technical	40098001
Supplemental	Adequate for RQ calculation; based on analysis of raw data,
the slope is 5.2 (C.I.: 2.6 – 7.9)

Pteronarcys californica	EC50 (96-hr) = 35 µg/L	Technical	40098001
Supplemental

	Freshwater Invertebrates (Chronic)

Daphnia magna	NOAEC = 0.0057 µg a.i./L

LOAEC = 0.0086 µg a.i./L	Technical	40452601	Acceptable	Based on
survival (all endpoints were affected in the study, the most sensitive
was survival)

Freshwater Fish (Acute)

Coho salmon	LC50 (24-hr) = >4,110 µg/L	Technical	40098001	Supplemental
Flow-through

Cutthroat trout	LC50 (96-hr) = 2,700 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 6,800 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 5,750 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 1,680 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 4,750 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 375 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 5,70 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 620 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 1,730 µg/L	Technical	40098001
Supplemental	“0 DAY DEGRA”

Cutthroat trout	LC50 (96-hr) = 470 µg/L	Technical	40098001	Supplemental
“7 DAY DEGRA”

Cutthroat trout	LC50 (96-hr) = 170 µg/L	Technical	40098001	Supplemental
“14 DAY DEGRA”

Cutthroat trout	LC50 (96-hr) = 340 µg/L	Technical	40098001	Supplemental
“21 DAY DEGRA”

Cutthroat trout	LC50 (96-hr) = 3,250 µg/L	80% wettable powder	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 5,220 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 4,400 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 6,170 µg/L	Technical	40098001
Supplemental

	Cutthroat trout	LC50 (96-hr) = 1,080 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,750 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,410 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 11,400 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,775 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 2,000 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 970 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 8,800 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,120 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 700 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 700 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 1,380 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 355 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 210 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 280 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 700 µg/L	80% wettable powder	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 700 µg/L	40.5% EC	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 1,400 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 4,250 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,020 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,820 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 860 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 72 µg/L	Technical	40098001	Supplemental
Not adequate for RQ calculation; legible raw data not available for
review

Rainbow trout	LC50 (96-hr) = 158 µg/L	Technical	40098001	Supplemental
Adequate for RQ calculation (reported as 156 in the M&E volume); no
slope could be calculated

Rainbow trout	LC50 (96-hr) = 1,400 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 3,500 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 5,850 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 167 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 3,500 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 4,500 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 310 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 2,600 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 2,500 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 780 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 820 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 430 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 370 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 580 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 780 µg/L	80% Wettable poweder	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 2,400 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,100 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 430 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 960 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 860 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 9,000 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 6,410 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,750 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 2,460 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 390 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 580 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 560 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 700 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 360 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 860 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 1,000 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,100 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 570 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 500 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 500 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 208 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 230 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 160 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 1,000 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 820 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 562 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 740 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 190 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 440 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 6,410 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 1,000 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 820 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 560 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 8,000 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 2,460 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 740 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 562 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 700 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 1,230 µg/L	Technical	40098001
Supplemental

	Rainbow trout	LC50 (96-hr) = 390 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 580 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 190 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 440 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 360 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 780 µg/L	Technical	40098001	Supplemental

	Rainbow trout	LC50 (96-hr) = 1,060 µg/L	80% Wettable powder	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 1,400 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 2,000 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 4,100 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 580 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 540 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 380 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 4,400 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 610 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 300 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 2,970 µg/L	Technical	40098001
Supplemental

	Atlantic salmon	LC50 (96-hr) = 10,400 µg/L	Technical	40098001
Supplemental

	Brook trout	LC50 (96-hr) = 3,500 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 2,500 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 9,400 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 1,100 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 8,400 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 3,400 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 470 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 240 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 2,420 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 620 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 9,200 µg/L	80% Wettable powder	40098001
Supplemental

	Brook trout	LC50 (96-hr) = 500 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 9,200 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 6,000 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 960 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 840 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 650 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 290 µg/L	Technical	40098001	Supplemental

	Brook trout	LC50 (96-hr) = 5,500 µg/L	40% EC	40098001	Supplemental

	Lake trout	LC50 (96-hr) = 550 µg/L	Technical	40098001	Supplemental

	Lake trout	LC50 (96-hr) = 1,030 µg/L	Technical	40098001	Supplemental

	Fathead minnow	LC50 (96-hr) = 7,900 µg/L	Technical	40098001
Supplemental

	Black bullhead	LC50 (96-hr) = 515 µg/L	Technical	40098001	Supplemental

	Channel catfish	LC50 (96-hr) = 2,200 µg/L	40.5% EC	40098001
Supplemental

	Channel catfish	LC50 (96-hr) = 7,600 µg/L	Technical	40098001
Supplemental

	Channel catfish	LC50 (96-hr) = 880 µg/L	Technical	40098001
Supplemental

	Bluegill	LC50 (96-hr) = 3,170 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = >50,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 50,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 10,300 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 10,300 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = >50,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 32,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 3,400 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,900 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 14,500 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 4,500 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,720 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,720 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 940 µg/L	80% Wettable powder	40098001
Supplemental

	Bluegill	LC50 (96-hr) = 5,200 µg/L	40.5% EC	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,500 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 600 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,300 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,500 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,500 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,700 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,650 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,200 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,050 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,050 µg/L	80% Wettable powder	40098001
Supplemental

	Bluegill	LC50 (96-hr) = 15,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 3,300 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 39,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 800 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 35,500 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 31,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 3,500 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 7,200 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,820 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 9,200 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 12,300 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 7,200 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 5,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,730 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 3,150 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,250 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 410 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 8,700 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 14,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 5,800 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 5,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,800 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 234 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 5,200 µg/L	40.5% EC	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 3,360 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 13,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 15,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 45,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 40,000 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 6,800 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 9,600 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 8,100 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,350 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,250 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 2,250 µg/L	Technical	40098001	Supplemental

	Bluegill	LC50 (96-hr) = 1,050 µg/L	80% Wettable powder	40098001
Supplemental

	Bluegill	LC50 (96-hr) = 1,880 µg/L	Technical	40098001	Supplemental

	Largemouth bass	LC50 (96-hr) = 3,450 µg/L	Technical	40098001
Supplemental

	Yellow perch	LC50 (96-hr) = 3,450 µg/L	Technical	40098001	Supplemental

	Fathead minnow	LC50 (96-hr) = 110,000 µg/L	Technical

	65495	Supplemental

	Adequate for RQ calculation; No analytical verification was reported
for any of the bioassays.

Bluegill	LC50 (96-hr) = 3,800 µg/L





Goldfish	LC50 (96-hr) = 100,000 µg/L





Guppy	LC50 (96-hr) = 7,200 µg/L





Bluegill	LC50 (96-hr) = 2,200 µg/L	Technical	91766	Acceptable

	Rainbow trout	LC50 (96-hr) = 1,600 µg/L	Technical	91766	Acceptable

	Freshwater Fish (Chronic)

Rainbow trout	NOAEC = 110 µg a.i./L

LOAEC = 234 µg a.i./L	Technical	425717-01	Acceptable	Early life-stage
study; endpoint based on increased time to swim up 

Estuarine/Marine Invertebrates (Acute)

Eastern oyster (Crassostrea virginica)	EC50 >114 mg a.i./L	Technical
444992-01	Acceptable	96-hr shell-deposition study; NOAEC = 83 mg a.i./L
(based on 16% decrease in shell deposition)

Estuarine/Marine Invertebrates (Chronic)

Mysid (Mysidopsis bahia)	NOAEC = 3.1 µg a.i./L

LOAEC = 6.7 µg a.i./L	Technical	444992-02	Acceptable	Flow-through,
life-cycle study; endpoints based on decreased number of neonates
produced, decreased survival, dreased weight, and decreased length

Thalassiosire pseudonana	LC50 = >50 mg a.i./L







TABLE A.2.  Summary of the Studies with the Most Sensitive Endpoints
from Submitted Toxicity Data for DDVP.

TAXON	ENDPOINT	FORMULATION	MRID	STUDY CLASS-IFICATION	COMMENTS

Birds (Acute)

Bobwhite quail (Colinus virginianus)	LD50 = 8.8 mg a.i./kg bw	Technical
40818301	Acceptable

	Birds (Sub-Acute)

Ring-necked pheasant (Phasianus colchicus)	LC50 =  568 mg a.i./kg-diet
Technical	0022923	Acceptable

	Birds (Chronic)

Mallard duck (Anas platyrhynchos)	NOAEC = 5 mg a.i./kg-diet

LOAEC = 15 mg a.i./kg-diet	Technical	44233401	Acceptable	Based on
reduced eggshell thickness, eggs laid, and number of viable embryos

Mammals  (Acute)

Laboratory rat (Rattus norvegicus)	LD50 = 56 mg a.i./kg-bw	Technical
0005467	Acceptable

	Mammals  (Chronic)

Laboratory rat (Rattus norvegicus)	NOAEC = 20 mg a.i./kg-diet

LOAEC = 80 mg a.i./kg-diet	Technical	42483901	Acceptable	Based on
reduced fertility and pup weight

Terrestrial Invertebrates

Honey bee (Apis mellifera)	LD50 = 0.5 µg a.i./bee (contact)	Technical
00036935	Acceptable

	Freshwater Invertebrates (Acute)

Water flea (Daphnia pulex)	EC50 = 0.066 µg a.i./L	Technical	40098001
Acceptable

	Freshwater Invertebrates (Chronic)

Water flea (Daphnia magna)	NOAEC = 0.0058 µg a.i./L

LOAEC = 0.0122 µg a.i./L	Technical	43890301	Acceptable	Based on reduced
egg production and growth (length and weight)

Freshwater Fish (Acute)

Cutthroat trout (Oncorhynchus clarki)	LC50 = 170 µg a.i./L	Technical
40098001	Acceptable

	Freshwater Fish (Chronic)

Rainbow trout (Oncorhynchus mykiss)	NOAEC = 5.2 µg a.i./L

LOAEC = 10.1 µg a.i./L	Technical	43788001	Acceptable	Based on decreased
post-hatch larval survival

Estuarine/Marine Invertebrates (Acute)

Mysid (Americamysis bahia)	EC50 = 19.1 µg a.i./L

	Technical	43571408	Acceptable

	Estuarine/Marine Invertebrates (Chronic)

Mysid (Americamysis bahia)	NOAEC = 1.48 µg a.i./L

LOAEC = 3.25 µg a.i./L	Technical	43854301	Acceptable	Based on reduced
growth (weight and length)

Estuarine/Marine Fish (Acute)

Sheepshead minnow (Cyprinodon variegates)	LC50 = 7,350 µg a.i./L
Technical	43571403	Acceptable

	Estuarine/Marine Fish (Chronic)

Sheepshead minnow (Cyprinodon variegates)	NOAEC = 960 µg a.i./L

LOAEC = 1840 µg a.i./L	Technical	43790401	Acceptable	Based on reduced
survival and length

 Appendix B. The Risk Quotient Method and Levels of Concern 

The Risk Quotient Method is the means used by EFED to integrate the
results of exposure and ecotoxicity data. For this method, Risk
Quotients (RQs) are calculated by dividing exposure estimates by the
acute and chronic ecotoxicity values (i.e., RQ = EXPOSURE/TOXICITY).
These RQs are then compared to OPP's levels of concern (LOCs). These
LOCs are criteria used by OPP to indicate potential risk to non-target
organisms and the need to consider regulatory action. EFED has defined
LOCs for acute risk, potential restricted use classification, and for
endangered species. 

The criteria indicate that a pesticide used as directed has the
potential to cause adverse effects on non-target organisms. LOCs
currently address the following risk presumption categories: 

(1) acute - there is a potential for acute risk; regulatory action may
be warranted in addition to restricted use classification; 

(2) acute restricted use - the potential for acute risk is high, but
this may be mitigated through restricted use classification; 

(3) acute endangered species - the potential for acute risk to
endangered species is high, regulatory action may be warranted; and 

(4) chronic risk - the potential for chronic risk is high, regulatory
action may be warranted. 

Currently, EFED does not perform assessments for chronic risk to plants,
acute or chronic risks to non-target insects, or chronic risk from
granular/bait formulations to mammalian or avian species. 

The ecotoxicity test values (i.e., measurement endpoints) used in the
acute and chronic RQs are derived from required studies. Examples of
ecotoxicity values derived from short-term laboratory studies that
assess acute effects are: (1) LC50 (fish and birds), (2) LD50 (birds and
mammals), (3) EC50 (aquatic plants and aquatic invertebrates), and (4)
EC25 (terrestrial plants). Examples of toxicity test effect levels
derived from the results of long-term laboratory studies that assess
chronic effects are: (1) the Lowest Observed Adverse Effect
Concentration (LOAEC) (birds, fish, and aquatic invertebrates), and (2)
the No Observed Adverse Effect Concentration (NOAEC) (birds, fish and
aquatic invertebrates). The NOAEC is generally used as the ecotoxicity
test value in assessing chronic effects. Risk presumptions, along with
the corresponding RQs and LOCs are summarized in Table B1.

Table B1.  Agency risk quotient (RQ) metrics and levels of concern (LOC)
per risk class.

Risk Class	Risk Description	RQ	LOC

Aquatic Animals (fish and invertebrates)

Acute	Potential for effects to non-listed animals from acute exposures
Peak EEC/LC501	0.5

Acute Restricted Use	Potential for effects to animals from acute
exposures

Risks may be mitigated through restricted use classification	Peak
EEC/LC501	0.1

Acute Listed Species	Listed species may be potentially affected by acute
exposures	Peak EEC/LC501	0.05

Chronic	Potential for effects to non-listed and listed animals from
chronic exposures 	60-day EEC/NOEC (fish)	1



21-day EEC/NOEC (invertebrates)

	Terrestrial Animals (mammals and birds)

Acute	Potential for effects to non-listed animals from acute exposures
EEC2/LC50 (Dietary)	0.5



EEC/LD50 (Dose)

	Acute Restricted Use	Potential for effects to animals from acute
exposures

Risks may be mitigated through restricted use classification	EEC2/LC50
(Dietary)	0.2



EEC/LD50 (Dose)

	Acute Listed Species	Listed species may be potentially affected by
acute exposures	EEC 2/LC50 (Dietary)	0.1



EEC/LD50 (Dose)

	Chronic	Potential for effects to non-listed and listed animals from
chronic exposures	EEC 2/NOAEC	1

Plants

Non-Listed 	Potential for effects to non-target, non-listed plants from
exposures	EEC/ EC25	1

Listed Plant	Potential for effects to non-target, listed plants from
exposures	EEC/ NOEC	1



EEC/ EC05

	1 LC50 or EC50. 2 Based on upper bound Kenaga values.



Appendix C.  Data Call-In Tables

The Environmental Fate and Effects Division (EFED) has completed a Data
Call-In (DCI) table for the trichlorfon (and DDVP) environmental fate
and effects data gaps identified in registration review.  The effects
data gaps may change if relevant toxicity data are identified from the
ECOTOX literature review.  The attached DCI tables, which include the
guideline number and study title for required data, also provides a
rationale for requiring the data, an explanation of how the data will be
used, and a brief description of how the data could impact the
Agency’s future decision-making.

Trichlorfon:

Guideline Number:  835.2120 

Study Title:  Hydrolysis

Rationale for Requiring the Data

Acceptable data have not been provided to quantify the hydrolysis of
trichlorfon. According to Code of Federal Regulations 40 (CFR40 2007)
Part 158 Subpart D (data requirements for pesticides) hydrolysis data
are required for pesticides with terrestrial or aquatic uses. Since
trichlorfon uses are classified as terrestrial and aquatic, hydrolysis
data for trichlorfon should be submitted to fulfill OPPTS Guideline
835.2120. 

Practical Utility of the Data

How will the data be used?

These data are used to estimate the degradation of trichlorfon in
aquatic systems and ultimately to derive aquatic EECs using PRZM/EXAMS. 

How could the data impact the Agency’s future decision-making?

In the case that these data are unavailable at the time risk assessments
are conducted, it will be assumed that trichlorfon is stable to
hydrolysis. If trichlorfon does degrade due to hydrolysis, this
assumption will result in overestimates of the concentrations of
trichlorfon in the environment.



Guideline Number:  835.2410

Study Title:  Photodegradation in soil

Rationale for Requiring the Data

Acceptable data have not been provided to quantify the photolysis of
trichlorfon in water. According to Code of Federal Regulations 40 (CFR40
2007) Part 158 Subpart D (data requirements for pesticides) aqueous
photolysis data are required for pesticides with terrestrial or aquatic
uses. Since trichlorfon uses are classified as terrestrial and aquatic,
aqueous photolysis data for trichlorfon should be submitted to fulfill
OPPTS Guideline 835.2410. 

Practical Utility of the Data

How will the data be used?

These data are used to characterize the degradation of trichlorfon in
soil. 

How could the data impact the Agency’s future decision-making?

In the case that these data are not submitted, it will be assumed that
trichlorfon is stable to photolysis on soil. 



Guideline Number:  835.4300 

Study Title:  Aerobic Aquatic Metabolism

Rationale for Requiring the Data

Acceptable data have not been provided to quantify the metabolism of
trichlorfon under aerobic aquatic conditions. According to Code of
Federal Regulations 40 (CFR40 2007) Part 158 Subpart D (data
requirements for pesticides) aerobic aquatic metabolism are required for
pesticides with terrestrial or aquatic uses. Since trichlorfon uses are
classified as terrestrial and aquatic, aerobic aquatic metabolism data
for trichlorfon should be submitted to fulfill OPPTS Guideline 835.4300.


Practical Utility of the Data

How will the data be used?

These data are used to estimate the degradation of trichlorfon in
aquatic systems and ultimately to derive aquatic EECs using PRZM/EXAMS. 

How could the data impact the Agency’s future decision-making?

In the case that these data are unavailable at the time risk assessments
are conducted, PRZM/EXAMS input parameter guidance default values will
be employed to account for aerobic aquatic metabolism. 



Guideline Number:  835.4400 

Study Title:  Anaerobic Aquatic Metabolism

Rationale for Requiring the Data

Acceptable data have not been provided to quantify the metabolism of
trichlorfon under anaerobic aquatic conditions. According to Code of
Federal Regulations 40 (CFR40 2007) Part 158 Subpart D (data
requirements for pesticides) anaerobic aquatic metabolism data are
required for pesticides with terrestrial or aquatic uses. Since
trichlorfon uses are classified as terrestrial and aquatic, anaerobic
aquatic metabolism data for trichlorfon should be submitted to fulfill
OPPTS Guideline 835.4400. 

Practical Utility of the Data

How will the data be used?

These data are used to estimate the degradation of trichlorfon in
aquatic systems and ultimately to derive aquatic EECs using PRZM/EXAMS. 

How could the data impact the Agency’s future decision-making?

In the case that these data are unavailable at the time risk assessments
are conducted, PRZM/EXAMS input parameter guidance default values will
be employed to account for anaerobic aquatic metabolism. 



Guideline Number:  835.1240 

Study Title:  adsorption/desorption

Rationale for Requiring the Data

Acceptable data have not been provided to quantify the
adsorption/desorption characteristics of trichlorfon in U.S. soils.
According to Code of Federal Regulations 40 (CFR40 2007) Part 158
Subpart D (data requirements for pesticides) adsorption/desorption data
are required for pesticides with terrestrial uses. Since trichlorfon
uses are considered to be terrestrial, an acceptable study should be
submitted to fulfill OPPTS Guideline 835.1240. This study should define
Kd and KOC values of trichlorfon in U.S. soils. It is preferred that
this study be conducted using a batch equilibrium method.

Practical Utility of the Data

How will the data be used?

These data are used to estimate the transport of trichlorfon from
treatment sites to aquatic systems and ultimately to derive aquatic EECs
using PRZM/EXAMS. 

How could the data impact the Agency’s future decision-making?

In the absence of these data, EFED will assume that there is no sorption
of trichlorfon to soils or organic matter on the treatment site.  In
order to implement this in derivation of aquatic EECs, a KOC value of 0
will be used to parameterize PRZM/EXAMS.  Input of a KOC value >0 is
expected to result in lower aquatic EECs. If acceptable data are
provided, the uncertainties associated with this assumption will be
reduced.



Guideline Number:  835.6200 

Study Title:  Aquatic Field Dissipation

Rationale for Requiring the Data

At this time, no acceptable studies are available to describe the
dissipation of trichlorfon under aquatic field conditions.  According to
Code of Federal Regulations 40 (CFR40 2007) Part 158 Subpart D (data
requirements for pesticides), aquatic field dissipation data are
required for pesticides with aquatic uses. Since trichlorfon uses are
classified as aquatic, aquatic field dissipation data for trichlorfon
should be submitted to fulfill OPPTS Guideline 835.6200.

Practical Utility of the Data

How will the data be used?

These data are used to characterize the fate of trichlorfon in the
aquatic environment resulting from direct applications to water. 

How could the data impact the Agency’s future decision-making?

These data are useful to validate laboratory fate data of trichlorfon
with a field study that accounts for all of the fate processes studied
under laboratory conditions (e.g., hydrolysis, photolysis).



Guideline Number: 835.6100 (7), 835.6200 (7)

Study Title: Environmental Chemistry Methods

Rationale for Requiring the Data

Independently validated analytical methods for residues in soil and
water (environmental chemistry methods) submitted by the registrant are
used to evaluate analyses described in submitted environmental fate and
ecological effects studies.  Submitted analytical methods are also used
by various Federal, State, Tribal, and local agencies to detect and
monitor residues that are or are suspected to be in environmental
compartments due to outdoor uses and accidental releases.  Therefore,
availability of these analytical methods is necessary in order to
protect human health and the environment from trichlorfon residues in
the environment.  Independent laboratory validations for submitted
analytical methods are necessary to confirm the levels of detection and
quantitation reported in registrant-prepared validations.

Use of trichlorfon may impact surface water quality due to runoff of
rain water and drift of residues.  Therefore, analytical methods for are
necessary for detecting trichlorfon residues in water and in soil or
sediment.

Practical Utility of the Data

How will the data be used?

In the absence of independently validated environmental chemistry
methods, submitted environmental fate and ecological effects data may
not be reviewable and entities outside the Agency may lack
chemical-specific methods for analyses in environmental compartments. 
Independently validated environmental chemistry methods will be used to
evaluate the submitted environmental fate and ecological effects data
and will be made available to the public to support monitoring for
trichlorfon residues.

How could the data change the Agency’s decision, or impact the
Agency’s future decision-making?  

Risk assessment conclusions could be altered if they are not supported
by either study data or environmental monitoring detections that are
based on independently validated environmental chemistry methods. 
Furthermore, while not directly related to Agency decision-making,
independently validated environmental chemistry methods are necessary in
order to protect human health and the environment from use of
trichlorfon.



Guideline Number:  850.2100 

Study Title:  Avian Acute Oral Toxicity Test (mallard duck or bobwhite
quail and a passerine species)

Rationale for Requiring the Data

No acceptable acute avian oral toxicity data were submitted for
trichlorfon.  The new Part 158 data requirements [40 CFR Part 158 (CFR
40 2007)] specify that acute avian oral toxicity data be submitted for
either mallard duck or bobwhite quail and a passerine species. The
available chronic toxicity data for mallard ducks and bobwhite quails
demonstrate that trichlorfon can cause toxic effects in these birds. In
addition, avian data for other organophosphate (OP) insecticides,
including dimethoate, show that a passerine species, such as the
red-winged blackbird, are one order of magnitude more sensitive than
other tested bird species to acute OP insecticide exposure (USEPA 2008).
 Therefore, an avian oral toxicity test is required for passerine birds
and either the mallard duck or the bobwhite quail, as specified in 40
CFR Part 158. A passerine study protocol must be submitted for review by
the Agency prior to initiation of this study.

Practical Utility of the Data

How will the data be used?

Acute avian oral toxicity data will be used to identify potential risks
to birds from acute exposure to trichlorfon.  The data will reduce
uncertainties associated with the current risk assessment for birds and
will improve the Agency’s understanding of the potential effects of
trichlorfon on terrestrial species.  If oral acute toxicity data are not
submitted for any bird, than risk to birds from acute exposure to
trichlorfon will be assumed.  

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without
these data, the Agency would have to assume that trichlorfon “may
affect” listed birds directly (and listed species from other taxa
indirectly), and use of trichlorfon and its formulated products may need
to be restricted in areas where listed species could be exposed. The
lack of these data will limit the flexibility the Agency and registrants
have in coming into compliance with the Endangered Species Act and could
result in use restrictions for trichlorfon use that are unnecessarily
severe.



Guideline Number:  850.2200 

Study Title:  Avian Dietary Toxicity Test (mallard duck and bobwhite
quail)

Rationale for Requiring the Data

No acceptable sub-acute avian dietary toxicity data were submitted for
trichlorfon.  The new Part 158 data requirements [40 CFR Part 158 (CFR
40 2007)] specify that avian dietary toxicity data be submitted for both
a waterfowl and upland game species. The available chronic toxicity data
for mallard ducks and bobwhite quails demonstrate that trichlorfon can
cause toxic effects in these birds.  Therefore, an avian dietary
toxicity test is required for mallard ducks and bobwhite quails as
specified in 40 CFR Part 158. 

Practical Utility of the Data

How will the data be used?

Sub-acute avian dietary toxicity data will be used to identify potential
risks to birds from acute exposure to trichlorfon.  The data will reduce
uncertainties associated with the current risk assessment for birds and
will improve the Agency’s understanding of the potential effects of
trichlorfon on terrestrial species.  If dietary toxicity data are not
submitted for any bird, than risk to birds from dietary exposure to
trichlorfon will be assumed.  

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without
these data, the Agency would have to assume that trichlorfon “may
affect” listed birds directly (and listed species from other taxa
indirectly), and use of trichlorfon and its formulated products may need
to be restricted in areas where listed species could be exposed. The
lack of these data will limit the flexibility the Agency and registrants
have in coming into compliance with the Endangered Species Act and could
result in use restrictions for trichlorfon use that are unnecessarily
severe.



Guideline Number: 850.1075 

Study Title:  Fish Acute Toxicity Test, Estuarine/Marine

Rationale for Requiring the Data

Acute toxicity data are not available for estuarine and marine fish. 
The updated Part 158 data requirements, published in October 2007,
specify that acute toxicity data are required on one estuarine/marine
mollusk (guideline fulfilled), one estuarine/marine invertebrate
(guideline not fulfilled), and one estuarine/marine fish (guideline not
fulfilled) for terrestrial (food crop, feed crop, and nonfood), aquatic
food crop, and nonfood (outdoor), forestry, and residential outdoor
uses.  Trichlorfon has terrestrial (turf), aquatic nonfood
(ornamental/bait ponds) and residential outdoor uses registered, and
therefore, the acute estuarine/marine organism toxicity studies are
required.

In the absence of these data, an acute-to-chronic ratio (ACR) would
normally be derived; and the acute toxicity to estuarine and marine fish
would be estimated based on the ACR for freshwater fish.  However, there
are currently no toxicity data (acute or chronic) for estuarine/marine
fish, therefore, an ACR cannot be derived.  In addition, three of the
four reported ecological incidents associated with the use of
trichlorfon have involved fish kills. 

Practical Utility of the Data

How will the data be used?

Estuarine/marine fish acute toxicity data will be used to determine the
potential for trichlorfon to affect fish species in estuarine/marine
environments. The data will reduce uncertainties associated with the
current risk assessment for estuarine/marine fish and will improve the
Agency’s understanding of the potential effects of trichlorfon on
aquatic animals.  In the absence of data specific for these fish, data
from freshwater fish species will be used as a surrogate for
estuarine/marine fish.

How could the data impact the Agency’s future decision-making?

Using toxicity data from a freshwater species as a surrogate for
estuarine/marine species increases the uncertainty for assessing risks
to estuarine/marine species in screening-level assessments. 
Additionally, if future endangered species risk assessments are
performed without these data, the Agency would have to presume risk to
listed estuarine/marine fish species in the absence of such data for
trichlorfon. Therefore, the use of trichlorfon and its formulated
products may need to be restricted in areas where listed species could
be exposed. The lack of these data will limit the flexibility the Agency
and registrants have in coming into compliance with the Endangered
Species Act and could result in use restrictions for trichlorfon that
are unnecessarily severe.



Guideline Number: 850.1035 

Study Title:  Mysid Acute Toxicity Test

Rationale for Requiring the Data

Although, acute toxicity data are available for an estuarine/marine
mollusk, no acute data are currently available for a non-mollusk
estuarine/marine invertebrate.  The updated Part 158 data requirements,
published in October 2007, specify that acute toxicity data are required
on one estuarine/marine mollusk (guideline fulfilled), one
estuarine/marine invertebrate (guideline not fulfilled), and one
estuarine/marine fish (guideline not fulfilled) for terrestrial (food
crop, feed crop, and nonfood), aquatic food crop, and nonfood (outdoor),
forestry, and residential outdoor uses.  Trichlorfon has terrestrial
(turf), aquatic nonfood (ornamental/bait ponds) and residential outdoor
uses registered, and therefore, the acute estuarine/marine organism
toxicity studies are required.

In the absence of these data, an acute-to-chronic ratio (ACR) would
normally be derived; and the acute toxicity to estuarine/marine
invertebrates would be estimated based on the ACR for freshwater
invertebrates.  However, the freshwater invertebrate data necessary for
calculating the ACR are not available.  Chronic data are not available
for the most acutely sensitive freshwater species (Pteronarcella badia).
 

Practical Utility of the Data

How will the data be used?

Estuarine/marine invertebrate acute toxicity data will be used to
determine the potential for trichlorfon to affect non-mollusk
invertebrate species in estuarine/marine environments. The data will
reduce uncertainties associated with the current risk assessment for
estuarine/marine invertebrates and will improve the Agency’s
understanding of the potential effects of trichlorfon on aquatic
animals.  In the absence of data specific for these invertebrates, data
from freshwater invertebrate species will be used as a surrogate for
estuarine/marine invertebrates.

How could the data impact the Agency’s future decision-making?

Using toxicity data from a freshwater species as a surrogate for
estuarine/marine species increases the uncertainty for assessing risks
to estuarine/marine species in screening-level assessments. 
Additionally, if future endangered species risk assessments are
performed without these data, the Agency would have to presume risk to
listed non-mollusk estuarine/marine invertebrate species in the absence
of such data for trichlorfon. Therefore, the use of trichlorfon and its
formulated products may need to be restricted in areas where listed
species could be exposed. The lack of these data will limit the
flexibility the Agency and registrants have in coming into compliance
with the Endangered Species Act and could result in use restrictions for
trichlorfon that are unnecessarily severe.



Guideline Number: 850.1400 

Study Title:  Fish Early Life-Stage Toxicity Test, Estuarine/Marine

Rationale for Requiring the Data

Chronic toxicity data are not available for estuarine and marine fish. 
In the absence of these data, an acute-to-chronic ratio (ACR) would
normally be derived; and the chronic toxicity to estuarine and marine
fish would be estimated based on the ACR for freshwater fish.  However,
there are currently no toxicity data (acute or chronic) for
estuarine/marine fish, therefore, an ACR cannot be derived. 
Additionally, due to the potential use pattern of trichlorfon , exposure
to estuarine/marine environments is possible.  Therefore, an early
life-stage toxicity study is required for estuarine/marine fish, as
specified in 40 CFR Part 158. 

Practical Utility of the Data

How will the data be used?

Estuarine/marine fish chronic toxicity data will be used to determine
the potential for trichlorfon to affect fish species in estuarine/marine
environments. The data will reduce uncertainties associated with the
current risk assessment for estuarine/marine fish and will improve the
Agency’s understanding of the potential effects of trichlorfon on
aquatic animals.  In the absence of data specific for these fish, data
from freshwater fish species will be used as a surrogate for
estuarine/marine fish.

How could the data impact the Agency’s future decision-making?

Using toxicity data from a freshwater species as a surrogate for
estuarine/marine species increases the uncertainty for assessing risks
to estuarine/marine species in screening-level assessments. 
Additionally, if future endangered species risk assessments are
performed without these data, the Agency would have to presume risk to
listed estuarine/marine fish species in the absence of such data for
trichlorfon. Therefore, the use of trichlorfon and its formulated
products may need to be restricted in areas where listed species could
be exposed. The lack of these data will limit the flexibility the Agency
and registrants have in coming into compliance with the Endangered
Species Act and could result in use restrictions for trichlorfon that
are unnecessarily severe.



Guideline Number:  850.4100, 850.4150 

Study Title:  Terrestrial Plant Toxicity Test, Tier I (Seedling
Emergence and Vegetative Vigor)

Rationale for Requiring the Data

Toxicity data for terrestrial plants are not available for trichlorfon. 
The current 40 CFR Part 158 data requirements, require Tier I level
seedling emergence and vegetative vigor terrestrial plant data for all
insecticides.  Additionally, other OPs are known to be phytotoxic (e.g.,
tribufos, a plant defoliant).  Therefore, Tier I plant toxicity studies
(seedling emergence and vegetative vigor) are required for terrestrial
plants, as specified in 40 CFR Part 158.  

Practical Utility of the Data

How will the data be used?

Vegetative vigor and seedling emergence data for terrestrial plants will
be used to determine the potential for trichlorfon to affect non-target
plant species in the terrestrial environment. The data will reduce
uncertainties associated with the current risk assessment for
terrestrial plants and will improve the Agency’s understanding of the
potential effects of trichlorfon on terrestrial plants.  In the absence
of data specific for these plants, risk to terrestrial plants will be
assumed.

How could the data impact the Agency’s future decision-making?

Because terrestrial plants form the basis of the food chain in many
terrestrial habitats, a solid understanding of the potential risks to
terrestrial plants is essential for sound environmental risk management
decision-making.  Without terrestrial plant data for trichlorfon, the
Agency cannot determine if the current application rates for trichlorfon
may result in direct adverse effects to terrestrial plants and/or
indirect effects resulting from reduction in the prey base and/or loss
of habitat/cover.  If future endangered species risk assessments are
performed without these data, the Agency would have to presume risk to
non-target terrestrial plants from use of trichlorfon. Therefore, use of
trichlorfon and its formulated products may need to be restricted in
areas where listed species could be exposed. The lack of these data will
limit the flexibility the Agency and registrants have in coming into
compliance with the Endangered Species Act and could result in use
restrictions for trichlorfon that are unnecessarily severe.



Guideline Number:  850.4400 

Study Title:  Aquatic plant toxicity (Tier I)

Rationale for Requiring the Data

Trichlorfon toxicity data for vascular and non-vascular aquatic plants
are not available.  Based on the 40 CFR Part 158 data requirements, Tier
I level non-target aquatic plant data are required for all insecticides.
 Additionally, other OPs are known to be phyotoxic (e.g., tribufos,
which is a defoliant).  Therefore, non-target aquatic plant data for
algae and vascular plants are required for trichlorfon at the Tier I
level.

Practical Utility of the Data

How will the data be used?

Data from Tier I aquatic plant toxicity studies will be used to estimate
potential risks to aquatic vascular and non-vascular plants associated
with the use of trichlorfon.  The data will reduce uncertainties
associated with the current risk assessment for aquatic plants and will
improve the Agency’s understanding of the potential effects of
trichlorfon on aquatic plants.  In the absence of Tier I data, risks for
both vascular and non-vascular aquatic plants will be presumed.

How could the data impact the Agency’s future decision-making?

Because aquatic vascular and non-vascular plants form the basis of the
food chain for aquatic habitats and significantly contribute to overall
water quality, a solid understanding of the potential risks to aquatic
plants is essential for sound environmental risk management
decision-making.  Without aquatic plant data for trichlorfon, the Agency
cannot determine if the current application rates for trichlorfon may
result in direct adverse effects to aquatic plants and/or indirect
effects resulting from reduction in the prey base and/or loss of
habitat/cover.  If future endangered species risk assessments are
performed without these data, the Agency would have to assume that
trichlorfon “may affect” aquatic plants directly (and listed species
from other taxa indirectly via reduction in prey base and/or habitat),
and use of trichlorfon may need to be restricted in areas where listed
species could be exposed.  The lack of these data will limit the
flexibility the Agency and registrants have in coming into compliance
with the Endangered Species Act and could result in use restrictions for
trichlorfon which are unnecessarily severe. 



DDVP:

Guideline Number:  850.2100 

Study Title:  Avian Acute Oral Toxicity Test

Rationale for Requiring the Data

Acceptable acute avian oral toxicity data were submitted for exposures
of bobwhite quail to DDVP; however, data are not available for
passerines, which are required under the new 40 CFR Part 158 (CFR 40
2007) data requirements for conventional pesticides (72 FR 60934; USEPA
2007c).  The available data for bobwhite quails show that DDVP is
classified as very highly toxic to birds on an acute exposure. In
addition, avian data for other organophosphate (OP) insecticides,
including dimethoate, show that a passerine species, such as the
red-winged blackbird, are one order of magnitude more sensitive than
other tested bird species to acute OP insecticide exposure.  Therefore,
an avian oral toxicity test is required for passerine birds, as
specified in 40 CFR Part 158. A passerine study protocol must be
submitted for review by the Agency prior to initiation of this study.

Practical Utility of the Data

How will the data be used?

Acute avian oral toxicity data will be used to identify potential risks
to birds from acute exposure to DDVP from the use of trichlorfon.  The
data will reduce uncertainties associated with the current risk
assessment for birds and will improve the Agency’s understanding of
the potential effects of trichlorfon on terrestrial species.  If oral
acute toxicity data are not submitted for passerines, than risk to
passerines from acute exposure to DDVP from the use of trichlorfon will
be assumed.  

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without
these data, the Agency would have to assume that trichlorfon “may
affect” listed passerine species directly (and listed species from
other taxa indirectly), and use of trichlorfon and its formulated
products may need to be restricted in areas where listed species could
be exposed. The lack of these data will limit the flexibility the Agency
and registrants have in coming into compliance with the Endangered
Species Act and could result in use restrictions for trichlorfon use
that are unnecessarily severe.



Guideline Number:  850.4100, 850.4150 

Study Title:  Terrestrial Plant Toxicity Test, Tier I (Seedling
Emergence and Vegetative Vigor)

Rationale for Requiring the Data

Toxicity data for terrestrial plants are not available for DDVP.  The
current 40 CFR Part 158 data requirements, require Tier I level seedling
emergence and vegetative vigor terrestrial plant data for all
insecticides.  Additionally, other OPs are known to be phytotoxic (e.g.,
tribufos, a plant defoliant).  Therefore, Tier I plant toxicity studies
(seedling emergence and vegetative vigor) are required for terrestrial
plants, as specified in 40 CFR Part 158.  

Practical Utility of the Data

How will the data be used?

Vegetative vigor and seedling emergence data for terrestrial plants will
be used to determine the potential for DDVP (from the use of
trichlorfon) to affect non-target plant species in the terrestrial
environment. The data will reduce uncertainties associated with the
current risk assessment for terrestrial plants and will improve the
Agency’s understanding of the potential effects of trichlorfon on
terrestrial plants.  In the absence of data specific for these plants,
risk to terrestrial plants will be assumed.

How could the data impact the Agency’s future decision-making?

Because terrestrial plants form the basis of the food chain in many
terrestrial habitats, a solid understanding of the potential risks to
terrestrial plants is essential for sound environmental risk management
decision-making.  Without terrestrial plant data for DDVP, the Agency
cannot determine if the current application rates for trichlorfon may
result in direct adverse effects to terrestrial plants and/or indirect
effects resulting from reduction in the prey base and/or loss of
habitat/cover.  If future endangered species risk assessments are
performed without these data, the Agency would have to presume risk to
non-target terrestrial plants from use of trichlorfon. Therefore, use of
trichlorfon and its formulated products may need to be restricted in
areas where listed species could be exposed. The lack of these data will
limit the flexibility the Agency and registrants have in coming into
compliance with the Endangered Species Act and could result in use
restrictions for trichlorfon that are unnecessarily severe.



Guideline Number:  850.4400 

Study Title:  Aquatic plant toxicity (Tier I)

Rationale for Requiring the Data

DDVP toxicity data for vascular and non-vascular aquatic plants are not
available.  Based on the 40 CFR Part 158 data requirements, Tier I level
non-target aquatic plant data are required for all insecticides. 
Additionally, other OPs are known to be phyotoxic (e.g., tribufos, which
is a defoliant).  Therefore, non-target aquatic plant data for algae and
vascular plants are required for DDVP at the Tier I level.

Practical Utility of the Data

How will the data be used?

Data from Tier I aquatic plant toxicity studies will be used to estimate
potential risks to aquatic vascular and non-vascular plants from DDVP
exposure associated with the use of trichlorfon.  The data will reduce
uncertainties associated with the current risk assessment for aquatic
plants and will improve the Agency’s understanding of the potential
effects of trichlorfon on aquatic plants.  In the absence of Tier I
data, risks for both vascular and non-vascular aquatic plants will be
presumed.

How could the data impact the Agency’s future decision-making?

Because aquatic vascular and non-vascular plants form the basis of the
food chain for aquatic habitats and significantly contribute to overall
water quality, a solid understanding of the potential risks to aquatic
plants is essential for sound environmental risk management
decision-making.  Without aquatic plant data for DDVP, the Agency cannot
determine if the current application rates for trichlorfon may result in
direct adverse effects to aquatic plants and/or indirect effects
resulting from reduction in the prey base and/or loss of habitat/cover. 
If future endangered species risk assessments are performed without
these data, the Agency would have to assume that trichlorfon “may
affect” aquatic plants directly (and listed species from other taxa
indirectly via reduction in prey base and/or habitat), and use of
trichlorfon may need to be restricted in areas where listed species
could be exposed.  The lack of these data will limit the flexibility the
Agency and registrants have in coming into compliance with the
Endangered Species Act and could result in use restrictions for
trichlorfon which are unnecessarily severe. 



 

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Ingestion

Birds / Amphibians

Wet/dry deposition

Root uptake

Long range atmospheric transport

Dermal uptake/Ingestion

Ingestion

Ingestion

Ingestion

Ingestion

Soil

Exposure

Media

Mammals

Runoff

Terrestrial/riparian plants

grasses/forbs, fruit, seeds (trees, shrubs)

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Food chain

Reduction in prey

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Terrestrial 

insects

Birds / Terrestrial-phase amphibians / reptiles / mammals

Juvenile

Adult

Spray drift

Direct

application

Trichlorfon applied to use site

Trichlorfon degrading to DDVP

Attribute

Change

Receptors

Source

Stressor

Riparian plant terrestrial exposure pathways see Figure 3

Uptake/cell, 

roots, leaves

Aquatic Plants

Non-vascular

Vascular

Uptake/gills 

or integument

Ground water

Soil

Wet/dry deposition

Long range atmospheric transport

Ingestion

Ingestion

Uptake/gills 

or integument

Exposure

Media

Aquatic Animals

Invertebrates

Vertebrates

Runoff

Surface water/

Sediment

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Food chain

Reduction in algae

Reduction in prey

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Fish/aquatic-phase amphibians

Eggs     

Larvae 

Juveniles / Adults

Spray drift

Trichlorfon applied to use site

Trichlorfon degrading to DDVP

Attribute

Change

Receptors

Source

Stressor

