UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, DC 20460

			OFFICE OF  PREVENTION, PESTICIDES,  AND TOXIC SUBSTANCES

 

Chemical:	Diiodomethyl p-tolyl sulfone

PC Code:	101002

Case No.:	4009



January 8, 2008

Memorandum:

Subject:	Revised Environmental Hazards and Ecological Risk Assessment
for the Diiodomethyl p-tolyl sulfone RED. DP 344848.

To:	K. Avivah Jakob, Chemical Review Manager

	Regulatory Management Branch II

Antimicrobials Division (AD)

From: 	W. Erickson, Ph.D., Biologist

Risk Assessment and Science Support Branch (RASSB)/AD 

Thru:	Norm Cook, Branch Chief

RASSB/AD

Attached is the revised environmental hazards and ecological risk
assessment for Diiodomethyl p-tolyl sulfone.  The assessment is revised
to address The Dow Chemical Company's errors-only comments submitted on
December 20, 2007 in response to the draft assessment for the RED. 
Comments unrelated to errors are not addressed at this time.  The
following changes have been made:

        •	the active ingredient name is changed to Diiodomethyl
p-tolyl sulfone

        •	reference to uses being canceled (drains, grease traps,
nitrocellulose, and septic systems) is omitted

        •	EC50 and LC50 values for the daphnid study (MRID 00149729)
cited in Attachment A are corrected (note that the correct value was
cited in the assessment)

        •	the required label statement for antisapstain use is correct
as specified in the assessment; no change is made 

        •	the value for the mass of treated wood cited in Attachment B
is changed from 26,732 to 21,842



Table of Contents

Ecological Hazards Assessment . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

         Toxicity to Terrestrial Animals  . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

                 Birds, Acute and Subacute   . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

                 Mammals, Acute  . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

                 Nontarget Insects – Honeybees  . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

         Toxicity to Aquatic Organisms . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5

                 Freshwater Fish, Acute  . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

                 Freshwater Invertebrates, Acute . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6

                 Estuarine and Marine Organisms, Acute . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

                 Aquatic Organisms, Chronic . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

                 Aquatic Plants . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.  7

Ecological Risk Assessment and Characterization . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . 7

         Environmental Fate Summary . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

         Aquatic Exposure Assessment . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

         Aquatic Risk Assessment . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

         Terrestrial Risk Assessment . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

         Endangered Species Considerations . . . . . . . . . . . . . . .
. . . . . . . . . . .  . . . . . . . . . . . . . . . . . 13

Confirmatory Data Required. . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14

Required Label Statements . . . . . . . . . .  . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . .
 16

Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . .
18

         A:  Ecotoxicity Profile  . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . 18

         B:  Antisapstain Modeling  . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . . . 22

         C:  EECs for Diiodomethyl p-tolyl sulfone Leached from Wood
into Soil and Water . . . . . 31

Ecological Hazard and Environment Risk Assessment

Diiodomethyl p-tolyl sulfone

Diiodomethyl p-tolyl sulfone is registered as a bacteriostat, fungicide,
algaecide, insecticide, and miticide.  The active end-use products are
formulated as either ready-to-use solution, soluble concentrate, or
wettable powder.  Labeled uses include application as a materials
preservative in coatings, paints, adhesives, caulks, metalworking
fluids, paper, textiles, rubber; and protecting tanned leather from mold
or mildew.  Diiodomethyl p-tolyl sulfone is also used as an above-ground
wood preservative for control of mildew, sapstain, and wood-rotting
organisms at wood treatment facilities or is incorporated into other
registered wood preservatives.  

Environmental exposure levels from wood preservative applications may be
of concern for organisms exposed to leachate or runoff.  Therefore, an
ecological risk assessment is conducted for the wood preservative uses. 
Expected aquatic environmental concentrations (EECs) are modeled for
several wood-treatment uses, and risk quotients (RQs) are calculated by
comparing EECs to the most sensitive hazards endpoints for each
taxonomic group as identified in the hazards assessment.  Risk
characterization is based on comparing the RQs to the Agency's Levels of
Concern for acute and chronic risks to the various taxa.  

A hazards assessment is conducted for the other registered uses of
Diiodomethyl p-tolyl sulfone.  An ecological risk assessment is not
required for those uses at this time, because release and exposure
levels are expected to be low when products are applied according to
label directions and use precautions.  The hazards assessment is used to
meet current labeling requirements for precautionary statements and to
determine hazard endpoints for ecological organisms potentially exposed
in the event of a spill or other unintended environmental releases.

Ecological Hazards Assessment

The toxicity endpoints used in OPP's assessments are obtained from
guideline toxicity studies conducted for wildlife, aquatic organisms,
and plants (40 CFR §158.2060).  Guideline studies are required to
provide acute and reproductive/chronic measures of effect for one or
more test species in several taxonomic groups.  Some studies are only
required on a case-by-case basis, depending on factors such as use
patterns and environmental fate characteristics.  The available toxicity
endpoints and data requirements for Diiodomethyl p-tolyl sulfone are
summarized below and in more detail in Attachment A..  

	Toxicity to Terrestrial Animals

	

		Birds, Acute and Dietary

The Agency requires one acute-oral study to establish the toxicity of
Diiodomethyl p-tolyl sulfone (technical grade active ingredient, TGAI)
to birds for all registered uses.  The preferred test species is either
the mallard (Anas platyrhynchos) or the northern bobwhite (Colinus
virginianus).  Avian dietary toxicity studies (northern bobwhite and
mallard) are conditionally required for antimicrobial pesticides,
depending on the avian acute-oral toxicity, pertinent environmental fate
characteristics, and a potential for exposure.  Three available
acute-oral and dietary studies indicate that Diiodomethyl p-tolyl
sulfone is practically nontoxic to birds when ingested (Table 1), and an
avian precautionary statement is not required on product labels.  The
guidelines for avian acute-oral toxicity (OPPTS 850.2100) and avian
dietary toxicity OPPTS 850.2200) are satisfied.  

Table 1.  Acute-oral and Dietary Toxicity of Diiodomethyl p-tolyl
sulfone to Birds

Test

Species	Test

Type	% ai

tested	Toxicity

Endpoint	Toxicity Category	Study

Status	MRID No.

Northern bobwhite	acute oral	95	LD50 >2000 

(mg ai/kg bw)	practically nontoxic	core	123643

	dietary	95	LC50 >5620

(ppm)	practically nontoxic	core	123642

Mallard	dietary	95	LC50 >5620

(ppm)	practically nontoxic	core	124488

		

Mammals, Acute 

The available mammalian acute toxicity data indicate that Diiodomethyl
p-tolyl sulfone is practically nontoxic to mammals via oral (rat LD50
>5000 mg ai/kg bw) and dermal (rabbit LD50 >20,000 mg/kg) routes of
exposure.  Refer to the human toxicology chapter for more details on
these and other mammalian toxicity studies submitted for the
human-health assessment.

Nontarget Insects - Honeybees

No data are available for Diiodomethyl p-tolyl sulfone.  For wood
preservative use, a study addressing honey/beeswax residues and acute
toxicity of treated wood residues to bees is required (see Confirmatory
Data Required section); or, in lieu of this study, product labels with
wood preservative use can include a statement prohibiting use of
Diiodomethyl p-tolyl sulfone -treated wood for beehive construction (see
Label Statements section).  

	Toxicity to Aquatic Organisms

		Freshwater Fish, Acute

Two acute toxicity studies with the TGAI are required to establish the
toxicity of Diiodomethyl p-tolyl sulfone to freshwater fish.  The
preferred test species are the rainbow trout (Oncorhynchus mykiss), a
coldwater fish, and the bluegill (Lepomis macrochirus), a sunfish.  The
acute toxicity values from three available studies categorize
technical-grade Diiodomethyl p-tolyl sulfone as being highly to very
highly toxic to freshwater fish (Table 2).  Therefore, a precautionary
label statement is required.  The guideline for freshwater-fish acute
toxicity (OPPTS 850.1075) is satisfied.

Table 2.  Acute Toxicity of Diiodomethyl p-tolyl sulfone to Freshwater
Fish

Test

Species	% ai

tested	

96-h LC50

(µg ai/L)	

Toxicity Category	

Study Status	

MRID No.

Rainbow trout	97.7	66.7	very highly toxic	supplemental	47234001

	95	130	highly toxic	core	149730

Bluegill	95	750	highly toxic	core	149731



		Freshwater Invertebrates, Acute

A study with the TGAI is required to establish the acute toxicity of
Diiodomethyl p-tolyl sulfone to freshwater invertebrates.  The preferred
test species is Daphnia magna, a water flea.  Results from three
available studies categorize technical-grade Diiodomethyl p-tolyl
sulfone as being moderately to very highly acutely toxic to freshwater
invertebrates (Table 3).  Therefore, a precautionary label statement is
required.  The guideline requirement (OPPTS 850.1010) is satisfied.

Table 3.  Acute Toxicity of Diiodomethyl p-tolyl sulfone to Freshwater
Invertebrates

Test

Species	% ai

tested	48-h EC50

(µg ai/L)	Toxicity Category	Study Status	MRID No.

Water flea	97.7	279	highly toxic	core	47234002

	95	7,400a	moderately toxic	core	149729

	95	71b	very highly toxic	supplemental	123644

a the reported LC50 of 8 ppm in the Data Evaluation Report has been
readjusted to an EC50, based on immobility of 

   test daphnids reported at the 10 ppm test concentration

b daphnids were entrapped at the air-water interface in all test
concentrations; the presence of the toxicant at the solution surface,
and the resulting entrapment of the test organisms, likely influenced
the incidence of daphnid mortality

		Estuarine and Marine Organisms, Acute

Acute toxicity testing with estuarine/marine organisms using the TGAI is
required when the end-use product is intended for direct application to
the marine/estuarine environment or the active ingredient is expected to
reach this environment in significant concentrations because of its
expected use and mobility.  The preferred test species are the
sheepshead minnow (Cyprinodon variegatus), mysid shrimp (Mysidopsis
bahia), and Eastern oyster (Crassostrea virginica).  Data are required
to support the wood preservative uses of Diiodomethyl p-tolyl sulfone. 
No data are available.  

		Aquatic Organisms, Chronic 

Chronic toxicity testing (fish early life stage and aquatic invertebrate
life cycle) is required for antimicrobial pesticides when certain
conditions apply.  For Diiodomethyl p-tolyl sulfone, these conditions
include acute toxicity to freshwater organisms and solubility and
persistence of the major degradates as discussed in the environmental
fate assessment.  Preferred freshwater test species are the rainbow
trout and Daphnia magna.  No data are available.  Chronic testing is
required for a freshwater fish and a freshwater invertebrate.  The
preferred test material is the major degradate, MIMPTS (parent minus one
iodo group).

Aquatic plants

The use of Diiodomethyl p-tolyl sulfone as a wood treatment may result
in the active ingredient reaching the aquatic environment.  Aquatic
plant toxicity data are required to assess this risk.  Testing is
conducted with one species of aquatic vascular plant (duckweed, Lemna
gibba) and four species of algae:  (1) freshwater green alga,
Selenastrum capricornutum, (2) marine diatom, Skeletonema costatum, (3)
freshwater diatom, Navicula pelliculosa, and (4) bluegreen
cyanobacteria, Anabaena flos-aquae.  The rooted aquatic macrophyte rice
(Oryza sativa) is also tested in seedling emergence and vegetative vigor
tests.  Testing is required for Diiodomethyl p-tolyl sulfone, because
wood preservative applications may expose aquatic plants to the active
ingredient.  A study has been submitted for the green alga but has not
yet been reviewed.  No other data are available. 

Ecological Risk Assessment and Characterization

Risk assessment and characterization integrates exposure and toxicity
information to evaluate the potential for adverse ecological effects. 
Risk quotients (RQs) are determined for each taxa or ecological group by
comparing exposure estimates (Estimated Environmental Concentrations,
EECs) to the available acute and chronic ecotoxicity values, where:  

RQ = Exposure estimate (EEC) / Toxicity value

RQs are compared to OPP's levels of concern (LOCs).  Exceedance of an
LOC indicates a potential for acute or chronic adverse effects on
nontarget organisms and identifies a need for regulatory action to
mitigate risk.  LOCs currently address the following risk presumptions: 

acute: 	regulatory action may be warranted to reduce or preclude 

acute exposure

acute, listed species:	additional regulatory action may be warranted to
protect 

listed (i.e., endangered or threatened) species

chronic:	regulatory action may be needed to reduce or preclude 

chronic exposure 



The LOCs for the various risk presumptions are listed below for
terrestrial and aquatic animals and plants: 

	Aquatic 

Animals	Terrestrial Animals   	

Plants

Acute:	0.5	0.5	1

Acute, listed species:	0.05	0.1	1

Chronic:	1	1	n/a



The following toxicity endpoints are used as inputs to the RQ method for
expressing risk: 

Aquatic Animals

Acute:	Lowest tested EC50 or LC50 for freshwater fish and invertebrates
and estuarine/marine fish and invertebrates 

Chronic:	Lowest NOEC for freshwater fish and invertebrates and
estuarine/marine fish and invertebrates (early life-stage or full
life-cycle tests)

Terrestrial Animals

Avian acute: 

	Lowest LD50 (single oral dose) and LC50 (subacute dietary)

Avian chronic:	Lowest NOEC (21-week avian reproduction test)

Mammalian acute:	Lowest LD50 from single oral dose test.

Mammalian

chronic:	Lowest NOEC for two-generation reproduction test

Plants

Terrestrial:	Lowest EC25 values from both seedling emergence and
vegetative vigor for both monocots and dicots

Terrestrial

listed:	Lowest EC05 or NOEC for both seedling emergence and vegetative
vigor for both monocots and dicots

Aquatic vascular

and algae:	Lowest EC50 



When available, toxicity measures or other appropriate information from
non-guideline studies or from the open literature also may be used to
characterize risk.  

OPP generally uses computer simulation models to estimate exposure of
aquatic organisms to an active ingredient.  These models estimate EECs
in surface waters using product-label information (e.g., treatment site,
application rate, application method,) and available environmental-fate
data to determine how fast the pesticide breaks down and its expected
movement in the environment.  The models used in the risk assessment for
Diiodomethyl p-tolyl sulfone wood preservative uses are described in
more detail in the Aquatic Exposure Assessment section.

Environmental Fate Summary 

Diiodomethyl p-tolyl sulfone degrades by hydrolysis and metabolism to
form dehalogenated and demethylated compounds.  Diiodomethyl p-tolyl
sulfone is stable to hydrolysis at pH 5, but degrades at pH 7 and 9 to
form MIMPTS (monoiodo-p-tolylsulfone), which only degrades slightly. 
Water solubility and vapor pressure increases as degradation continues,
but volatility from water is negligible because of increasing
solubility.  Significant bioconcentration is not expected from parent
Diiodomethyl p-tolyl sulfone or the metabolites based on the low (<3)
log Kow (Log P).  Release to water from treated soil and wood are
significant routes of dissipation.  

Acute exposure to parent Diiodomethyl p-tolyl sulfone may occur, but
chronic exposure is not likely.  Parent half-lives range from 1.5-9.6
days in hydrolysis (pH 7-9) and in metabolism studies.  Aqueous residues
of parent Diiodomethyl p-tolyl sulfone were higher than sediment
residues for seven days in the anaerobic aquatic metabolism study
(representing bottom sediment).

Chronic exposure to aquatic organisms is likely to occur from MIMPTS
(parent minus one iodo group) and from MPTS (parent minus both iodo
groups).  MIMPTS was the terminal residue in hydrolysis and aqueous
photodegradation studies. MIMPTS was stable in non-irradiated soil but
degraded with a half-life of 12.5 day in the irradiated samples.  In
aerobic soil (the top layer of non-flooded soil), the half-lives of
MIMPTS and MPTS were 32 and 53-173 days, respectively.   In anaerobic
soil (the second layer of soil), MIMPTS was a major degradate with a
half-life of 21 days and was found predominantly in water.  MPTS reached
81 % by the end of the study and was primarily found in water. 
Anaerobic aquatic metabolism (representing bottom sediment) degrades 
MIMPTS with a total system half-life of 11 days.  MPTS was the terminal
metabolite and increased to 95 % by 4-6 months.  Aqueous residues were
greater than sediment residues for MIMPTS and MPTS for 180 and 60 days,
respectively.  

In addition, Diiodomethyl p-tolyl sulfone degrades to residues with
greater polarity and water solubility than itself.  The water
solubilities of parent, MIMPTS, and MPTS from the EPI-Suite model 0.8,
175, and 1750 mg/l, respectively.  Therefore, aqueous residues of
Diiodomethyl p-tolyl sulfone metabolites will likely be present for
extended periods of time from treated wood on land.

Aquatic Exposure Assessment

Diiodomethyl p-tolyl sulfone has a potential to reach the aquatic
environment due to movement of leachate from treated wood.  Therefore,
EECs are modeled for antisapstain treatment and for wood treated by
pressurized spray and used for purposes such as houses, fences, decks,
and transmission poles.  Based on communication from the registrant, AD
presumes that treated wood will not be placed in surface waters (e.g.,
pilings) nor will topical application (e.g., brush-on) be made to wood
(e.g., docks) located in water bodies.  However, a label statement
prohibiting such use needs to be added to product labels with wood
preservative uses.

	Antisapstain treatment

Storm water runoff concentrations of Diiodomethyl p-tolyl sulfone are
estimated for a hypothetical lumber yard where Diiodomethyl p-tolyl
sulfone is applied as an antisapstain (wood preservative) treatment. 
The methodology is based on a screening-level model to determine runoff
concentrations of pesticides from antisapstain facilities in British
Columbia, Canada (Krahn and Straub (1990).  The concentration of
Diiodomethyl p-tolyl sulfone in runoff is calculated by dividing its
concentration in leachate by a storm water dilution factor.  For
example, with the dilution factor of 15, Diiodomethyl p-tolyl sulfone
leachate entering the storm drain is assumed to be diluted with
uncontaminated runoff water at a 1:15 ratio.  This dilution factor value
is based on measurements of runoff in storm drains at facilities using
antisapstain chemicals in British Columbia.  The dilution factor ratios
of 1:6 and 1:23 were used by Krahn and Straub (1990) to represent a
“general industry wide” range of predicted runoff concentrations. 
Estimated runoff concentrations for Diiodomethyl p-tolyl sulfone are
presented in Table 4.  See Attachment A for information on the
calculations used to derive these estimations and the associated
uncertainties and limitations of the model.  

Table 4.  Estimated Runoff Concentrations for Antisapstain Treatment

Parameter	Dilution Factor	Estimated Runoff Concentration (µg ai/L)

Low-end dilution	6	33

Typical dilution	15	13

High-end dilution	23	9



Other wood preservative uses

EECs resulting from leaching of Diiodomethyl p-tolyl sulfone from
treated lumber into soil and surface waters were calculated for six
uses, including transmission poles, fence posts, fences, deck posts,
decks, and houses.  Use scenarios were evaluated using an estimate of
the maximum cumulative aqueous release of Diiodomethyl p-tolyl sulfone
from a treated wood over a 14-day period.  The methodology for this
analysis is based on an environmental risk assessment previously
prepared by the Rohm and Haas (2006) for
4,5-dichloro-2-n-octyl-3(2H)-isothiazolone (DCOIT).  In this
methodology, leaching of Diiodomethyl p-tolyl sulfone from treated wood
surfaces is modeled to estimate soil loadings and concentrations.  Soil
concentrations and other input data are then used with EPA’s Express
model EXAMS-PRZM Exposure Simulation Shell (version 1.03.02) to estimate
concentrations in surface water.  The EECs are presented in Table 5. 
See Attachment B for information on the calculations used to derive
these EECs and the associated uncertainties and limitations of the
methodology.

 Table 5.  Aquatic EECs for Various Wood Preservatives Uses of
Diiodomethyl p-tolyl sulfone

Use	Aquatic EEC (µg ai/L)

	instantaneous	21-day	60-day

House	0.127	0.028	0.010

Deck	0.024	0.005	0.002

Transmission Pole	0.007	0.002	<0.001

Fence	0.002	<0.001	<0.001

Deck Post	0.001	<0.001	<0.001

Fence Post	<0.001	<0.001	<0.001



Aquatic Risk Assessment

	Freshwater Fish

The risk presumptions for freshwater fish potentially exposed to
Diiodomethyl p-tolyl sulfone from antisapstain and pressurized-spray
treatments are presented in Table 6.  The LOC is not exceeded for
non-listed fish for any scenario but is exceeded for listed (i.e.,
endangered and threatened) species for all three dilution-rate scenarios
from antisapstain treatment.  

Table 6.  Acute Risk Quotients and Risk Presumptions for Freshwater Fish


Use	EEC

(µg ai/L)	Toxicity

(µg ai/L)	acute RQ	acute LOCs

exceeded

Antisapstain treatment:

Low dilution

(1:6)	33	66.7	0.49	listed species

Typical dilution

(1:15)	13	66.7	0.19	listed species

High dilution

(1:23)	9	66.7	0.13	listed species

Pressurized-spray treatment:

House	0.127	66.7	0.002	none

Deck	0.024	66.7	<0.001	none

Transmission pole	0.007	66.7	<0.001	none

Fence	0.002	66.7	<0.001	none

Deck Post	0.001	66.7	<0.001	none

Fence Post	<0.001	66.7	<0.001	none



	Freshwater aquatic invertebrates

The risk presumptions for freshwater invertebrates potentially exposed
to Diiodomethyl p-tolyl sulfone from antisapstain and pressurized-spray
treatments are presented in Table 7.  The LOC is not exceeded for
non-listed invertebrates for any scenario but is exceeded for listed
(i.e., endangered and threatened) species for all three dilution-rate
scenarios from antisapstain treatment.  

Table 7.  Acute Risk Quotients and Risk Presumptions for Freshwater
Invertebrates 

Use	EEC

(µg ai/L)	Toxicity

(µg ai/L)	acute RQ	acute LOCs

exceeded

Antisapstain treatment:

Low dilution

(1:6)	33	71	0.46	listed species

Typical dilution

(1:15)	13	71	0.18	listed species

High dilution

(1:23)	9	71	0.12	listed species

Pressurized-spray treatment:

House	0.127	71	0.002	none

Deck	0.024	71	<0.001	none

Transmission pole	0.007	71	<0.001	none

Fence	0.002	71	<0.001	none

Deck Post	0.001	71	<0.001	none

Fence Post	<0.001	71	<0.001	none



Terrestrial Risk Assessment

Because Diiodomethyl p-tolyl sulfone is practically nontoxic to birds
and mammals, minimal acute risk is presumed for all registered uses. 
Toxicity data are not available to assess risk to honey bees.  However,
if use of treated wood is prohibited in bee hives (see Required Label
Statements section), minimal exposure and risk are presumed.

Endangered Species Considerations

Section 7 of the Endangered Species Act (ESA), 16 U.S.C. Section
1536(a)(2), requires that federal agencies consult with the National
Marine Fisheries Service (NMFS) for marine and andronomus listed
species, or with the United States Fish and Wildlife Services (FWS) for
listed wildlife and freshwater organisms, if proposing an "action" that
may affect listed species or their designated habitat.  Each federal
agency is required under the Act to insure that any action they
authorize, fund, or carry out is not likely to jeopardize the continued
existence of a listed species or result in the destruction or adverse
modification of designated critical habitat.  To jeopardize the
continued existence of a listed species is to "to engage in an action
that reasonably would be expected, directly or indirectly, to reduce
appreciably the likelihood of both the survival and recovery of a listed
species in the wild by reducing the reproduction, numbers, or
distribution of the species." 50 C.F.R. §402.02.

To comply with subsection (a)(2) of the ESA, EPA’s Office of Pesticide
Programs has established procedures to evaluate whether a proposed
registration action may directly or indirectly appreciably reduce the
likelihood of both the survival and recovery of a listed species in the
wild by reducing the reproduction, numbers, or distribution of any
listed species (U.S. EPA 2004).  If any of the Listed Species LOC
Criteria are exceeded for either direct or indirect effects in the
Agency’s screening-level risk assessment, the Agency identifies any
listed or candidate species that may occur spatially and temporally in
the footprint of the proposed use.  Further biological assessment is
undertaken to refine the risk.  The extent to which any species may be
at risk determines the need to develop a more comprehensive consultation
package as required by the ESA.

For certain use categories, including most Diiodomethyl p-tolyl sulfone
uses, the Agency assumes there will be minimal environmental exposure,
and only a minimal toxicity data set is required (Overview of the
Ecological Risk Assessment Process in the Office of Pesticide Programs
U.S. Environmental Protection Agency - Endangered and Threatened Species
Effects Determinations, 1/23/04, Appendix A, Section IIB, p 81).  Uses
in these categories do not undergo a full screening-level risk
assessment and are considered to fall under a no effect determination.  

The assessment for antisapstain wood treatment uses indicates that there
is a potential for Diiodomethyl p-tolyl sulfone exposure of listed
freshwater and aquatic invertebrate species and that a more refined
assessment is warranted, to include direct, indirect and habitat
effects.  The refined assessment should involve clear delineation of the
action area associated with proposed use of Diiodomethyl p-tolyl sulfone
and best available information on the temporal and spatial co-location
of listed species with respect to the action area.  This analysis has
not been conducted for this assessment.  An endangered species effect
determination will not be made at this time.  The label statement
required for wood preservative products is expected to provide some
mitigation until a full endangered species assessment is conducted.

Confirmatory Data Required To Support Wood Treatment Uses:

	•  Estuarine/marine fish acute study (850.1075); TGAI 

	•  Estuarine/marine shrimp acute study (850.1035); TGAI     

	•  Estuarine/marine mollusk acute study (850.1025); TGAI

	•  Aquatic invertebrate (freshwater) life-cycle study (850.1300);
major degradate

	•  Fish early life-stage (freshwater) study (850.1400); major
degradate

	•  Freshwater diatom (850.5400); TGAI or EP

	•  Marine diatom (850.5400); TGAI or EP

	•  Blue-green cyanobacteria (850.5400); TGAI or EP

	•  Freshwater green alga (850.5400); TGAI or EP; note:  a study has
been submitted but not yet reviewed

	•  Freshwater floating macrophyte duckweed (850.4400); TGAI or EP

	•  Freshwater rooted macrophyte rice seedling emergence (850.4225);
EP

	•  Freshwater rooted macrophyte rice vegetative vigor (850.4250); EP

	•  A study addressing honey/beeswax residues and acute toxicity of
treated wood residues to bees is required if bee hives might be
constructed of treated wood or if any product is intended for
application to a bee hive.  The study is a combination of Guidelines
171-4 and 850.3030 (see information regarding residue data requirements
for uses in beehives in the residue chemistry section of 40 CFR part
158).  The toxicity portion of this study is conducted in lieu of a
honeybee contact LD50 test. The number of bees tested and the
methodology for collection/ introduction of bees into hives, feeding,
and observations for toxicity and mortality must be consistent with
those described in OPPTS Guideline 850.3030, “Honey Bee Toxicity of
Residues on Foliage”.  However, this study will be waived if product
labels with wood preservative use are amended to prohibit the use of
treated wood for beehive construction (see section IV Label Hazard
Statements). 

Required Label Statements

All product labels must have the following ENVIRONMENTAL HAZARDS
statement:  

"This pesticide is toxic to fish and aquatic invertebrates. Do not
contaminate water when disposing of equipment washwaters.  Do not
discharge effluent containing this product into lakes, streams, ponds,
estuaries, oceans, or other waters unless in accordance with the
requirements of a National Pollutant Discharge Elimination System
(NPDES) permit and the permitting authorities are notified in writing
prior to discharge.  Do not discharge effluent containing this product
to sewer systems without previously notifying the local sewage treatment
plant authority.  For guidance contact your State Water Board or
Regional Office of the EPA."

Product labels having antisapstain use must have the following
DIRECTIONS FOR USE statement:

"Treated lumber must be stored under cover, indoors, or at least 100
feet from any pond, lake, stream, wetland, or river to prevent possible
runoff of the product into the waterway.  Treated lumber stored within
100 feet of a pond, lake, steam, wetland, or river must be either
covered with plastic or surrounded by a berm to prevent surface water
runoff into the nearby waterway.  If a berm or curb is used around the
site, it should consist of impermeable material (clay, asphalt,
concrete) and be of sufficient height to prevent runoff during heavy
rainfall events."

Products with wood preservative uses:  if honeybee studies 850.3030 and
171-4 are waived, the following label statement is required:  

“Treated wood shall not be used in the construction of beehives.”

Products with wood preservative uses almost must have a statement
prohibiting use of pretreated wood in structures located in surface
waters and prohibiting application of Diiodomethyl p-tolyl sulfone to
existing structures located or to be placed in surface waters.

References

Bollmeier, A. (1990) Angus Chemical Company Phase 3 Summary of MRID
00149729. Acute Toxicity of AMICAL 48  to Daphnia magna: Static Acute
Toxicity: Report No. 31947. Prepared by ABC Labs., Inc. 1 p.  MRID
94039006

Bollmeier, A. (1990) Angus Chemical Company Phase 3 Summary of MRID
00149731. Acute Toxicity of AMICAL 48 to Bluegill Sunfish: Static Acute
Toxicity: Report No. 31945. Prepared by ABC Labs. Inc. 10 p.  MRID
94039004

Bollmeier, A. (1990) Angus Chemical Company Phase 3 Summary of MRID
00149730. Acute Toxicity of AMICAL 48 to Rainbow Trout: Static Acute
Toxicity: Report No. 31946. Prepared by ABC Labs., Inc. 1 p.  MRID
94039005

Fink, R.; Beavers, J.; Grimes, J.; et al. (1978) Acute Oral LD50--
Bobwhite Quail: A-9248: Project No. 161-104. Final rept. (Unpublished
study received Sep 7, 1979 under 275-21; prepared by Wildlife
International Ltd. and Washington College, submitted by Abbott
Laboratories, North Chicago, IL; CDL:240936-C)  MRID 123643

Fink, R.; Beavers, J.; Joiner, G.; et al. (1978) Eight-day Dietary
LC50--Bobwhite Quail: A-9248: Project No. 161-105. Final rept.
(Unpublished study received Sep 7, 1979 under 275-21; prepared by
Wildlife International Ltd. and Washington College, submitted by Abbott
Laboratories, North Chicago, IL; CDL:240936-B)  MRID 123642

Fink, R.; Beavers, J.; Grimes, J.; et al. (1978) Eight-day Dietary
LC50--Mallard Duck: A-9248: Project No. 161-106. Final rept.
(Unpublished study received Sep 7, 1979 under 275-21; prepared by
Wildlife International Ltd. and Washington College, submitted by Abbott
Laboratories, North Chicago, IL; CDL:240936-A)  MRID 124488

Forbis, A.; Burgess, D.; Georgie, L. (1984) Acute Toxicity of Amical 48
to Daphnia magna: Static Acute Toxicity Report # 31947. Unpublished
study prepared by Analytical Biochemistry Laborato- ries, Inc. 38 p. 
MRID 149729

Forbis, A.; Georgie, L.; Burgess, D. (1984) Acute Toxicity of Ami- cal
48 to Rainbow Trout (Salmo gairdneri): Static Acute Toxicity Report
#31946. Unpublished study prepared by Analytical Bio- chemistry
Laboratories, Inc. 60 p.   MRID 149730

Forbis, A.; Georgie, L.; Burgess, D. (1984) Acute Toxicity of Ami- cal
48 to Bluegill Sunfish (Lepomis macrochirus): Static Acute Toxicity
Report #31945. Unpublished study prepared by Analyti- cal Biochemistry
Laboratories, Inc. 63 p.  MRID 149731

Hamlin, J. (1972) Report to: Abbott Laboratories, Chemical Divi- sion:
Four-Day Static Fish Toxicity Studies with Amical 48 and Amical 77 in
Rainbow Trout and Bluegills: IBT No. A1244. (Unpublished study received
Mar 9, 1972 under 275-22; prepared by Industrial Bio-Test Laboratories,
Inc., submitted by Abbott Laboratories, North Chicago, Ill.;
CDL:002251-H)  MRID 55326	

Krahn, P.; Strub R. (1990)  Standard Leaching Test for Antisapstain
Chemicals:  Regional Program Report 90-10.  Environment Canada,
Conservation and Protection, Pacific and Yukon Region North Vancouver,
BC.

Marino, T. A. (2007) AMICAL 48: An Acute Toxicity Study with the Rainbow
Trout; The Dow Chemical Company; Guideline 72-1; 42 pages.

Marino, T. A. (2007) AMICAL 48: An Acute Toxicity Study with the
Daphnid, Daphnia magna; The Dow Chemical Company; Guideline 72-2; 42
pages.

Suprenant, D.; Ziencina, M. (1978) Acute Toxicity of A-9248 to the Water
Flea (Daphnia magna): Report #BW-78-9-308. (Unpub- lished study received
Sep 7, 1979 under 275-21; prepared by EG & G, Bionomics, submitted by
Abbott Laboratories, North Chicago, IL; CDL:240936-D)  MRID 123644

Trueblood, A. (1990) Angus Chemical Company Phase 3 Summary of MRID
00123643. Acute Oral Toxicity Study of AMICAL 48 in Bobwhite Quail:
Project #161-104. Prepared by Wildlife International, Ltd. 13 p.  MRID
94039001

Trueblood, A. (1990) Angus Chemical Company Phase 3 Summary of MRID
00123642. Eight-Day Dietary Toxicity Study of AMICAL 48 in Bobwhite
Quail: Project #161-105. Prepared by Wildlife International Ltd. 12 p. 
MRID 94039002

Trueblood, A. (1990) Angus Chemical Company Phase 3 Summary of MRID
00124488. Eight-Day Dietary Toxicity Study of AMICAL 48 in the Mallard
Duck; Project No. 161-106. Prepared by Wildlife International, Ltd. 12
p.  MRID 94039003

Attachment A:  Ecotoxicity Profile for Diiodomethyl p-tolyl sulfone

Guideline No./

Study Type	MRID No./

Reference Information/

Study Classification	Dosing and Animal Information	Results

Aquatic Fauna Toxicity



850.1010

Aquatic invertebrate acute toxicity, test, freshwater daphnids

(Daphnia magna)

	

MRID 00123644

Suprenant, D., Ziencina, M. (1978). Acute Toxicity of A-9248 to the
Water Flea (Daphnia magna): Report #BW-78-9-308. (Unpublished study
received Sep 7, 1979 under 275-21; prepared by EG & G, Bionomics,
submitted by Abbott Laboratories, North Chicago, IL; CDL:240936-D). 

Supplemental

	

Test material administered as solution in acetone at concentrations of
0.017, 0.029, 0.048, 0.079, 0.13, 0.22, 0.36, and 0.60 mg/L for 48
hours. 

15 daphnids/group

Purity: 95%

	

LC50 = 0.71 ug/L

Daphnids were entrapped at the air-water interface in all test
concentrations. It was suggested that the presence of the toxicant at
the solution surface, and the resulting entrapment of the test
organisms, directly influenced the incidence of daphnid mortality. 

Very highly toxic to aquatic invertebrates



850.1010

Aquatic invertebrate acute toxicity, test, freshwater daphnids

(Daphnia magna)

	MRID 00149729

Forbis, A., Burgess, D., Georgie, L. (1984). Acute Toxicity of Amical 48
to Daphnia magna: Static Acute Toxicity Report # 31947. Unpublished
study prepared by Analytical Biochemistry laboratories, Inc. 38 p. 

Core	In range testing experiment 10/group were exposed to concentrations
of 0.1, 1.0, 10.0 and 100 mg/L test material (95% a.i.) 

Subsequent bioassay conducted using a 10 daphnia/group exposed to
concentrations of 1.0, 1.8, 3.2, 5.6 and 10.0 mg/L for 48 hours. 

	LC50 = 8 mg/L (5.6 – 10)

EC50 = 7.4 mg/L

The no observed-effect concentration level was 3.2 ppm after 48 hours
which was based on the lack of mortality and abnormal effects. 

Moderately toxic to aquatic invertebrates



850.1010

Aquatic invertebrate acute toxicity, test, freshwater daphnids

(Daphnia magna)	MRID 47234002

Marino, T.; Yaroch, A.; Arnold, B.; et al. (2007) Amical 48 Antifungal
Agent: An Acute Toxicity Study with the Daphnid, Daphnia magna.
Unpublished study prepared by Dow Chemical Co. 42 p.

Core	Test material administered at 0,  36.3, 69.7, 116, 196, 335, and
538 ug/L

2 replicates at 10 daphnids/replicate

Purity: 97.7%	24-hour EC50 >538 ug/L (HDT)

48-hour EC50: 279 ug/L

48-hour NOEC: 36.3 ug/L (Based on highest concentration

exhibiting no immobility or sublethal effects.)





850.1075

Fish acute toxicity test, freshwater and marine

(Rainbow Trout)

	

MRID 00149730

Forbis, A., Georgie, L., Burgess, D. (1984). Acute Toxicity of Amical 48
to Rainbow Trout (Salmo gairdneri): Static Acute Toxicity Report #31946.
Unpublished study prepared by Analytical Bio-chemistry Laboratories,
Inc. 60 p. 

Core	

96-h range finding study conducted with preliminary test concentrations
of 0.1, 1.0 and 10.0 mg/L test material (95% a.i.) 

Definitive bioassay conducted by exposing 10 Rainbow trout/group to test
material concenrations of 0.018, 0.032, 0.056, 0.10 and 0.18 mg/L 

 	

LC50 = 0.13 ppm

No effect concentration based on lack of mortality  and abnormal effects
after 96 hours was 0.100 mg/L. Mortality was observed only in the 0.180
mg/L test concentration during the 96-hour exposure period. 

Highly toxic to Rainbow trout



850.1075

Fish acute toxicity test, freshwater and marine

(Bluegill Sunfish)

	MRID 00149731

Forbis, A., Georgie, L., Burgess, D. (1984). Acute Toxicity of Amical 48
to Bluegill Sunfish (lepomis macrochirus): Static Acute Toxicity Report
#31945. Unpublished study prepared by Analytical Biogeochemistry
Laboratories, Inc. 63 p. 

Core	Two range finding studies conducted by exposing sunfish to test
material (95% a.i.) at concentrations of 0.10, 1.0. 10.0 and 100 mg/L.
Definitive assay was conducted with 10 Bluegill sunfish/concentration at
doses of 0.32, 0.56, 1.0, 1.8, 3.2, 5.6 and 10.0 mg/L

	LC50 = 0.75 ppm (95% C.I. 0.56 – 1.0 mg/L). 

Highly toxic to bluegill sunfish



850.1075

Fish acute toxicity test, freshwater and marine

(Rainbow trout)

	MRID 47234001

Marino, T.; McClymont, E.; Yaroch, A. (2007) Amical 48 Antifungal Agent:
An Acute Toxicity Study with the Rainbow Trout, Oncorhynchus mykiss.
Unpublished study prepared by The Dow Chemical Company. 42 p.

Supplemental	Test material administered at 0, 10.1, 19.6, 32.0, 60.9,
89.9, and 151 ug/L

5 fish/test level

Purity: 97.7%	24-hour LC50= 150 ug/L (95% Confidence interval = 119-
>151 ug/L)

48-hour LC50= 92.9 ug/L (95% Confidence interval = 80.4- 107 ug/L)

72-hour LC50= 70.3 ug/L (95% Confidence interval = 63.7-77.5 ug/L)

96-hour LC50= 66.7 ug/L (95% Confidence interval = 58.6-76.1 ug/L)

96-hour NOEC = 19.4 ug/L (Based on highest concentration exhibiting

no mortality or sublethal effects.)

Terrestrial Wildlife Toxicity



850.2100

Avian acute oral toxicity test

(Bobwhite Quail)

	

MRID 00123643

Fink, R., Beavers, J., Grimes, J. et al. (1978). Acute Oral
LD50-BobwhiteQuail: A-9248: Project No. 161-104. Final rept.
(Unpublished study received Sept 7, 1979 under 275-21; prepared by
Wildlife International Ltd. And Washington College, submitted by Abbott
Laboratories, North Chicago, IL; CDL: 240936-C). 

 Core

	

Single dose of test material in corn oil administered via intubation at
doses of 398, 631, 1000, 1590, or 2510 mg/kg 

10 test individuals/group

Purity: 95% 

	

LD50 > 2000 ppm

Practically non-toxic to avian species. 





850.2200

Avian dietary toxicity test

(Bobwhite Quail)

	

MRID 00123642

Fink, R., Beavers, J., Joiner, G. et al. (1978). Eight-day Dietary
LC50-Bobwhite Quail: A-9248: Project No. 161-105. Final rept.
(Unpublished study received Sep 7, 1979 under 275-21; prepared by
Wildlife International Ltd. And Washington College, submitted by Abbott
Laboratories, North Chicago, IL; CDL: 240936-B). 

Core

	

Test material administered in diet at concentrations of 562, 1000, 1780,
3160 and 5620 ppm for 5 days. Positive controls administered Dieldrin in
corn at concentrations of 21.5, 31.6, 46.4, 68.2, and 100.00 ppm. 

10 test individuals/group

Purity: 95%

	

LC50 > 5000 ppm

No overt symptoms of toxicity observed at any treatment level. Final
body weights of test material treated birds were similar to control
birds, although a slight reduction in food consumption was observed in
birds fed higher levels of test material.  

Practically non-toxic to avian species

 



850.2200

Avian dietary toxicity test

(Mallard Duck)

	

MRID 00124488

Fink, R., Beavers, J., Grimes, J., et al. (1978). Eight-day Dietary
LC50-Mallard Duck: A-9248: Project No. 161-106. Final rept. (unpublished
study received Sep 7, 1979 under 275-21; prepared by Wildlife
International Ltd. and Washington College, submitted by Abbott
Laboratories, North Chicago, IL; CDL: 240936-A). 

Core	

Test material administered in corn oil 

at doses of 562, 1000, 1780, 3160 and 5620 ppm for 5 days. Dieldrin
(positive control) administered at doses of 72, 100, 139, 193 and 269
ppm. 

10 test individuals/group

Purity: 95%

	

LC50 > 5000 ppm

No mortality observed in any treatment groups. Toxic symptoms reported
on Day 6 for birds of the 5620 ppm dosage level. Symptoms included
lethargy, wing droop, loss of coordination, ruffled appearance and lower
limb weakness. Some birds remained lethargic through Day 7. Slight
depressions of body weight observed in 3160 ppm and 5620 ppm levels.
Food consumption also decreased in the 5620 ppm dose level. Gross
necroscopy revealed some mottling of lthe liver in one bird at the
highest concentration.

Practically non-toxic to waterfowl. 



Attachment B:  Antisapstain Modeling for Diiodomethyl p-tolyl sulfone

	UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

	WASHINGTON, D.C.  20460

	

						10/18/2007

	MEMORANDUM

	SUBJECT:	Antisapstain Modeling for Diiodomethyl p-tolyl sulfone 

		From:		Siroos Mostaghimi, Ph.D., Senior Scientist

		Risk Assessment and Science Support Branch (RASSB)

		Antimicrobials Division (7510P)

			To:	Norm Cook, Chief

		Risk Assessment and Science Support Branch (RASSB)

					Antimicrobials Division (7510P) 	 

  SEQ CHAPTER \h \r 1 Attached please find the Estimated Environmental
Concentrations (EECs) for Diiodomethyl p-tolyl sulfone used as
antisapstain for wood treatment.  

Introduction

This memorandum presents estimates of concentrations of Diiodomethyl
p-tolyl sulfone in storm water runoff from lumber antisapstain treatment
facilities.  The methodology used for this analysis is based on an
approach developed to determine runoff concentrations of pesticides from
antisapstain facilities in British Columbia, Canada (Krahn and Strub,
1990). 

	The methodology used for this analysis is presented in Section 1. 
Section 2 presents the results of the analysis.  Limitations and key
assumptions of the analysis are discussed in Section 3, and Section 4
identifies referenced literature.

1. 	Methodology

	Components of the methodology described in this section include the
screening level leachate model and Diiodomethyl p-tolyl sulfone
application rates.

1.1 	Screening Level Leachate Model

Following a previously developed methodology, storm water runoff
concentrations of Diiodomethyl p-tolyl sulfone were estimated for a
hypothetical lumber yard where Diiodomethyl p-tolyl sulfone is applied
as an antisapstain (wood preservative) treatment.  The methodology is
based on an screening level model by Krahn and Strub (1990) to determine
runoff concentrations of pesticides from antisapstain facilities in
British Columbia, Canada.  

Following the model developed by Krahn and Straub (1990), the
concentration of Diiodomethyl p-tolyl sulfone in storm water runoff from
a wood treatment facility is calculated by dividing the concentration of
Diiodomethyl p-tolyl sulfone in leachate by a storm water dilution
factor, as shown in Equation 1.

This report presents Diiodomethyl p-tolyl sulfone storm water
concentration calculated with three dilution factor assumptions, 6, 15,
and 23, obtained from Krahn and Strub (1990).  For example, with the
dilution factor of 15, Diiodomethyl p-tolyl sulfone -bearing leachate
(Cleachate) entering the storm drain is assumed to be diluted with
uncontaminated runoff water at a 1:15 ratio.  This dilution factor value
is based on measurements of runoff in storm drains at facilities using
antisapstain chemicals in British Columbia.  The dilution factor ratios
of 1:6 and 1:23 were used by Krahn and Strub (1990) to represent a
“general industry wide” range of predicted runoff concentrations.  

Equation 1

 

Where:

Crunoff	=	Concentration of Diiodomethyl p-tolyl sulfone in runoff from
the facility (ppm) 

Cleachate	=	Concentration of Diiodomethyl p-tolyl sulfone in leachate
(i.e., the rainwater dripping directly off the wood, see Equation 2)

D	=	Dilution Factor (either 6, 15, or 23, unitless) 

To calculate the concentration of Diiodomethyl p-tolyl sulfone in runoff
from the facility (Crunoff), it is first necessary to calculate the
concentration of Diiodomethyl p-tolyl sulfone in leachate (Cleachate). 
Cleachate was calculated based on an approach developed by Krahn and
Strub (1990).  This approach assumes that the lumber yard consists of 16
sections with one stack each of treated lumber of various ages.  Each
stack of lumber is assumed to measure 2 feet high by 4 feet wide by 16
feet long.  Prior to any rain event, 1/16th of the yard inventory (i.e.,
one lumber stack) has never been exposed to rain, 1/16th of the yard
inventory has been exposed to 1 rain event, 1/16th of the yard inventory
has been exposed to 2 rain events, etc.  Therefore, the total leaching
period can be split into sixteen leaching cycles, each of which is
assumed to correspond to incremental 5-hour of leaching events (i.e.,
rainfall events).  The maximum leaching cycle (i.e., for the lumber
stack that has been exposed to 16 rain events) is 80 hours (i.e., 16
leaching cycles x 5 hours per cycle).  The leachate concentration
(Cleachate) is calculated by averaging the concentrations of
Diiodomethyl p-tolyl sulfone determined for each of the 16 leaching
cycles (Ci), as shown in Equation 2 below.

Equation 2

 

Where:

Cleachate	=       Concentration of Diiodomethyl p-tolyl sulfone in
leachate (ppm)

Ci	   =	Leachate concentration of Diiodomethyl p-tolyl sulfone
associated with leaching cycle i 	(see Equation 3)

Leachate concentrations of Diiodomethyl p-tolyl sulfone for leaching
cycles 1 through 16 (Ci) are calculated with Equation 3, which was
obtained from the antisapstain leachate analysis for ADBAC (Versar
2005).  It is necessary to estimate leachate concentrations using
Equation 3 because no leaching studies are available for Diiodomethyl
p-tolyl sulfone.   

Equation 3

 

Where:

Ci	=	Concentration of Diiodomethyl p-tolyl sulfone associated with
leaching cycle i (ppm or mg/L)

Mo            =        Mass of chemical applied to leachable portion of
wood at time t=0 (21,8422 mg) (See Equation 4)

ti	=	Time at which leaching cycle i ends (each leaching cycle is 5
hours) (5-80 hrs) 

Vleachate	=	Volume of leachate per stack of lumber (119 L) 

SAtop	=	Surface area of the top of a stack of lumber (5.95 m2)

SAtotal	=	Total surface area of the exposed to rain (i.e., all surfaces
except bottom) (13.4 m2)

I	=	Rainfall Intensity (0.003 m/hr)

KOC	=	Organic carbon partition coefficient(615 mg/L) 

Z	=	Surface thickness of leachable wood (0.01 m)

	The assumed values of Vleachate, SAtop, SAtotal, and I, which are shown
above, were obtained from Krahn and Strub (1990).  Koc is a
chemical-specific property, and was provided by EPA (2007).  The organic
carbon partition coefficient (Koc) is used in the methodology as a
screening-level predictor of the leaching behavior of Diiodomethyl
p-tolyl sulfone .  The assumed surface thickness of leachable wood
(i.e., 0.01 m) was obtained from EPA (2004).  Refer to Versar (2005) for
further details on the derivation of Equation 3. 

1.2 	Diiodomethyl p-tolyl sulfone Application Rate 

ICF reviewed product labels provided by EPA to identify antisapstain
application rates needed to calculate the mass of Diiodomethyl p-tolyl
sulfone applied to the leachable portion of the wood (Mo).  Application
rates were identified specifically for wood preservation uses of
Diiodomethyl p-tolyl sulfone, and these rates are summarized in Table 1.
 Treatment methods include spray or dip applications and pressure
treatments.  For this analysis, ICF based the Diiodomethyl p-tolyl
sulfone application rate on the highest rate of active ingredient
application indicated by the product labels.  For the products listed in
Table 1, the maximum application rate of the active ingredient is 1
percent (i.e., for Diiodomethyl p-tolyl sulfone Flowable or
Ultra-Fresh*15).

Table 1

Diiodomethyl p-tolyl sulfone Application Rates for Wood Preservation 

Product	Percent Active Ingredient	Application Rate for Analysis

AMICAL 48	95 percent

	0.3-1.0% (w/w) 



AMICAL WP	48.85 percent

	0.61-2.0% (w/w)



AMICAL Flowable	40 percent	0.3-1.0% (w/w a.i.) for typical end uses;
Minimum 0.5% (w/w a.i.) concentration for spray applications; For
pressure treatment, retention levels of 0.05-1.0 lb pcf are recommended;
Used with other wood preservatives at levels of 25-5,000 ppm.

Ultra-Fresh*15	15 percent	0.1-1.0% (w/w a.i.) for typical end uses; dip
applications must be submerged for at least one minute; Minimum 0.5%
(w/w a.i.) concentration for spray applications; Pressure treatment at
retention levels of 0.13-2.7 lb pcf. Used with other wood preservatives
at levels of 67-13,000 ppm.

Bazooka	0.95 percent	One gallon product per 2 to 500 gallons of water
for high-pressure spray applications; One gallon product per 20 to 1,000
gallons of water for dip applications

Wolman Clear	0.38 percent	150 to 300 square feet per gallon using brush,
dip roller, or spray



Equation 4, which was adapted from Versar (2005), was used to calculate
mass of Diiodomethyl p-tolyl sulfone applied to the leachable portion of
the wood (Mo).  Using this equation, Mo equals the product of the
maximum application rate of active ingredient, the uptake rate of the
wood, and the surface area of the leachable wood.  The assumed rate of
antisapstain uptake by wood (Uw) is based on the observed uptake rate
for Busan applied to freshly sawn pine boards by the dipping method
(Aschacher and Grundlinger 2000).  The surface area of leachable wood
was calculated using the lumber stack dimensions assumed by Krahn and
Straub (1990).  The leachable surface area is assumed not to include the
bottom of the lumber stack.

Equation 4

Mo=ARmax*Uw*SAlw*CONVgmg 

Where:

Mo		=	Mass of chemical applied to leachable portion of wood at time t=0
(21,842 mg)

ARmax		=	Maximum application rate of Diiodomethyl p-tolyl sulfone (1
percent)

Uw		=	Uptake rate of antisapstain solution by wood (163 g solution/ m2) 

SAlw 		=	Surface area of leachable wood (13.4 m2) 

CONVgmg 	=	Conversion factor from kilograms to milligrams (1,000 mg/g)

2. 	Results

Using the methods and inputs identified above, an Excel spreadsheet was
contructed to estimate the average concentration associated with each
leaching cycle.  As determined with Equation 3, the concentration of
leachate (Ci) for each of the sixteen leaching cycles is presented in
Table 2.  Due to chemical properties, Ci is constant for all leaching
cycles.

Table 2 

Estimated Leachate Concentration of Diiodomethyl p-tolyl sulfone for 

Each Leaching Cycle 

Leaching Cycle	Hours of Leaching	Leachate Concentration of Diiodomethyl
p-tolyl sulfone for Leaching Cycle i (Ci) (mg/L)

1	5	0.199

2	10	0.198

3	15	0.198

4	20	0.198

5	25	0.198

6	30	0.198

7	35	0.197

8	40	0.197

9	45	0.197

10	50	0.197

11	55	0.197

12	60	0.196

13	65	0.196

14	70	0.196

15	75	0.196

16	80	0.195



Using the Ci values identified in Table 2 and Equation 2, the
concentration of Diiodomethyl p-tolyl sulfone in leachate from all 16
sections of the lumber yard (i.e., Cleachate) was determined to be 0.197
mg/L.  Finally, the concentrations of Diiodomethyl p-tolyl sulfone in
storm water runoff from the lumber yard (Crunoff) were estimated using
Equation 1 and the dilution factors discussed in Section 1.1.  The
estimated runoff concentrations are presented in Table 3.

Table 3

Estimated Runoff Concentrations

Parameter	Dilution Factor	Estimated Runoff Concentration (ppm)

High-end dilution	23	0.009

Typical dilution	15	0.013

Low-end dilution	6	0.033



3. 	Assumptions and Limitations

Because no wood leaching studies are available for Diiodomethyl p-tolyl
sulfone, storm water runoff concentrations were estimated based on
methods previously developed by Krahn and Strub (1990) and Versar
(2005).  These methods involve various assumptions that may cause the
storm water runoff concentration to be over- or under-estimated.  Key
assumptions and limitations are identified below.  See the referenced
methodologies for further discussion of these and other limitations.

Concentrations of antisapstain chemical in runoff may be affected by
numerous variables including chemical formulation, chemical retention in
wood, rough vs. planed lumber cut, lumber packaging and stacking, drying
time prior to exposure to precipitation, precipitation duration,
precipitation intensity, precipitation frequency, precipitation pH,
quantity of treated lumber on the storage site, species of lumber
treated, general house keeping practices, whether the lumber is 1st,
2nd, or 3rd growth, solubility of the chemical in water, diffusion of
the chemical into the wood, additives in the formulations, exposure and
degradation due to ultraviolet light, microbial action, ambient
temperatures, and affinity of the chemical to soils and to yard surfaces
(Versar 2005). 

All rain events are assumed to be of equal intensity and duration.   

A dilution factor of 15 was obtained based on a study of antisapstain
facilities in British Columbia2.  The dilution factor is dependent on
the intensity of rainfall events.  It cannot be assumed that the average
rainfall intensity in British Columbia is representative of the average
rainfall intensity of the United States.  However, due to a lack of
better data, the average rainfall intensity in British Columbia was
used.  

Because uptake data for Diiodomethyl p-tolyl sulfone were not available,
the assumed rate of uptake by wood (163 g solution/m2) was based on the
observed uptake rate for Busan obtained from a study by Aschacher and
Grundlinger (2000).  This value may over- or under-estimate the uptake
rate for Diiodomethyl p-tolyl sulfone due to differences in
chemical-specific properties and experimental conditions (e.g.,
application method, environmental conditions).

.  

The model is sensitive to the selection of Z, the thickness of the
leachable region, and the depth to which the antisapstain is assumed to
penetrate.  Although the value of 0.01 m is based on the value used in
the Wood Leaching Model (WLM), it is unclear how this value was derived
and if use of the value is reasonable for a dipping treatment.

4. 	References

Aschacher G and Gruendlinger R, 2000.  Methods to evaluate the
ecotoxicological risks of anti-sapstain preservatives.  Holzforschung,
Austria Research and Development. 
www.holzforschung.at/english/img_eng/ascha200.pdf.

EPA, 2007.  “Amical Environmental Fate Data Based on Jim Breithaupt
Power Point Presentation,” document provided by Siroos Mostaghimi,
U.S. Environmental Protection Agency, October 4, 2007.

EPA, 2004. Wood Leaching Model: Chemical Concentration Screening Tool,
v1.0. USEPA/OPPT/AD.

Krahn P and Strub R, 1990.  Standard Leaching Test for Antisapstain
Chemicals:  Regional Program Report 90-10.  Environment Canada,
Conservation and Protection, Pacific and Yukon Region North Vancouver,
BC.

Lee R, 2004.  WLM recommendation regarding chemical generalization. 
Memorandum to Siroos Mostaghimi, USEPA.  December 15, 2004.

Versar, 2005. "ADBAC Antisapstain Modeling (TAF 1-4-10, CM-43),"
memorandum to Najim Shamim, U.S. EPA, from Ron Lee and Jignasha Patel,
Versar, Inc., December 5, 2005.

Attachment C:  EECs for Diiodomethyl p-tolyl sulfone Leached from Wood
into Soil and Water

	UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

	WASHINGTON, D.C.  20460

	10/24/2007

						

	MEMORANDUM

	SUBJECT:	Estimated Environmental Concentrations for Diiodomethyl
p-tolyl sulfone Leached from Wood into Soil and Water 

		From:		Siroos Mostaghimi, Ph.D., Senior Scientist

		Risk Assessment and Science Support Branch (RASSB)

		Antimicrobials Division (7510P)

			To:	Norm Cook, Chief

		Risk Assessment and Science Support Branch (RASSB)

					Antimicrobials Division (7510P) 	 

			Compound: Diiodomethyl p-tolyl sulfone

			Chemical No. : 101002

			Barcode:  345893

					  SEQ CHAPTER \h \r 1 Attached please find the estimated
environmental concentrations (EECs) for Diiodomethyl p-tolyl sulfone
leached from wood into soil and water.  

 

Introduction

This report presents estimated environmental concentrations of
Diiodomethyl p-tolyl sulfone in soil, surface water, and sediment pore
water resulting from the use of Diiodomethyl p-tolyl sulfone as a wood
preservative.  Diiodomethyl p-tolyl sulfone is registered for use as a
fungicide, algaecide, bacteriostat, insecticide, and miticide.  In
addition to its use as a wood preservative, it is registered for use in
coatings, paints, metalworking fluids, paper, textiles, septic systems,
drains, and pipes.  

The methodology for this analysis was based on an environmental risk
assessment previously prepared by the Rohm and Haas (2006) for
4,5-dichloro-2-n-octyl-3(2H)-isothiazolone (DCOIT).  In this
methodology, leaching of Diiodomethyl p-tolyl sulfone from treated wood
surfaces is modeled to estimate soil loadings and concentrations.  Next,
soil concentrations and other input data are used with EPA’s Express
model EXAMS-PRZM Exposure Simulation Shell (version 1.03.02) to estimate
concentrations in surface water and sediment pore water.  

Section 1 of this report presents the EECs for  Diiodomethyl p-tolyl
sulfone in soil.  Estimation of dissolved surface water and sediment
pore water concentrations of Diiodomethyl p-tolyl sulfone is presented
in Section 2.  Section 3 identifies assumptions, limitations, and
uncertainties of this analysis, and Section 4 identifies referenced
literature.

1. 	Estimation of Diiodomethyl p-tolyl sulfone Concentrations in Soil

This section describes the estimation of environmental concentrations of
Diiodomethyl p-tolyl sulfone in soil.  Soil concentrations of
Diiodomethyl p-tolyl sulfone are estimated for six wood preservative use
scenarios:  

a. transmission pole, 

b. fence post, 

c. fence, 

d. deck post, 

e. deck and,

f. house.  

Data, assumptions, and calculations for these use scenarios are
presented in Section 1.2.  Section 1.1 describes the approach used with
all use scenarios to estimate Diiodomethyl p-tolyl sulfone leaching from
treated wood surfaces.  Section 1.3 describes how soil concentrations
estimated for each use scenario were used to estimate soil compartment
loading rates for use with the Express model.

 

Cumulative Quantity of Diiodomethyl p-tolyl sulfone Leached Out of Wood

Leaching of Diiodomethyl p-tolyl sulfone from treated wood surfaces was
estimated based on chemical properties and a treated lumber leaching
methodology developed by Krahn and Strub (1990) and adapted by Versar
(2005).  The application of these methodologies is documented further
below and in EPA (2007).  Although one study of aqueous availability of
Diiodomethyl p-tolyl sulfone from treated wood is available (Williams
and Bradley, 1996), desorption rates from this study were not used
because the study has been rejected by EPA due to nonconformity with
standard methods.

All six wood preservative use scenarios were evaluated using an estimate
of the maximum cumulative aqueous release of Diiodomethyl p-tolyl
sulfone from a treated wood over a 14 day period.  This estimate, 114
mg/m2 (i.e., 114 mg of Diiodomethyl p-tolyl sulfone released per m2 of
treated wood surface), is calculated using an Excel spreadsheet.  The
data, assumptions, and methods used to calculate the leaching rate are
consistent with a separate analysis to estimate Diiodomethyl p-tolyl
sulfone runoff concentrations from antisapstain treatment facilities
(EPA, 2007).  The assumed leaching duration of 14 days was chosen to be
consistent with the Rohm and Haas (2006) methodology, as described
further below.

Krahn and Strub (1990) developed a methodology to measure rainfall
leaching of antisapstain chemicals from treated wood.  Stacks of treated
lumber (2 feet x 4 feet x 16 feet) were placed outdoors above leachate
collection trays, and leachate was collected following a five hour
rainfall event.  The volume of leachate collected, the concentration of
the leachate, and the surface area of lumber exposed to rainfall may
then be used to calculate the mass of antisapstain chemical released per
square meter of wood surface during the 5-hour rain cycle.  Kahn and
Strub (1990) then used this experiment to devise a protocol for
estimating leaching and surface runoff from a lumber yard containing 16
lumber stacks of various ages.  

The Krahn and Strub (1990) methodology was used to estimate runoff of
the antisapstain chemical ADBAC from a hypothetical lumber yard. 
However, actual field tests were not performed and no wood leaching
studies were available to estimate leaching from a lumber stack. 
Therefore, Equation 1 was developed to estimate leaching from a lumber
stack and leaching cycle as defined by Krahn and Strub (1990).

Equation 1

 

Where:

Ci	=	Concentration of leachate produced during a five-hour leaching
cycle i (ppm or 

		mg/L)

Mo            =      Mass of chemical applied to leachable portion of
wood at time t = 0 (21,842 mg from ICF, 2007)

ti	=	Time at which leaching cycle i ends (each leaching cycle is 5
hours) (i + 5 hrs) 

Vleachate	=	Volume of leachate per stack of lumber (119 L calculated
from Krahn and 

		Strub, 1990) 

SAtop	=	Surface area of the top of a stack of lumber (5.95 m2 calculated
from 

		Krahn and Strub, 1990)

SAtotal	=	Total surface area of the exposed to rain (i.e., all surfaces
except bottom; 13.4 

		m2 calculated from Krahn and Strub, 1990)

I	=	Rainfall Intensity (0.003 m/hr from Versar, 2005)

KOC	=	Organic carbon partition coefficient(615 mL/g from EPA, 2007) 

Z	=	Surface thickness of leachable wood (0.01 m from Versar, 2005)

	Parameter values and sources for this Equation 1 are shown with the
parameter definitions.  In this equation, the chemical specific leaching
behavior is predicted using the organic carbon partition coefficient
(Koc).  For more explanation of how this Equation 1 was derived, refer
to EPA (2007) and Versar (2005). 

Rohm and Hass (2006) estimated soil environmental concentrations using
leaching rates obtained from an aqueous leaching study in which a
treated block of wood was immersed for 14 days.  To make the
Diiodomethyl p-tolyl sulfone analysis consistent with this approach, the
rainfall leaching methodology described above used to calculate leaching
for 67 rainfall cycles of 5 hours each, which total 13.9 days.  The
cumulative quantity of Diiodomethyl p-tolyl sulfone leached per m2 of
treated wood over the 14 day time period was then calculated to be 114
mg/m2.  All calculations are provided in an Excel spreadsheet submitted
with this memorandum.  

Diiodomethyl p-tolyl sulfone Use Scenarios

Six Diiodomethyl p-tolyl sulfone use scenarios were used to estimate
post-application environmental concentrations in soil.  The use
scenarios included application of Diiodomethyl p-tolyl sulfone to
transmission poles, fence posts, fencing, deck posts, decking, and wood
clad houses. 

Transmission Poles

The environmental concentrations in soil following application of
Diiodomethyl p-tolyl sulfone to a transmission pole was estimated by
first calculating the quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of the soil surrounding a transmission pole, as shown in
Equation 2.  This value (Qpole) is the product of the sum of the treated
wood surface areas above and below ground and the cumulative quantity of
Diiodomethyl p-tolyl sulfone leached per 1 m2 of treated wood over a 14
day period (Rohm and Haas, 2006). 

Equation 2:

 Qpole = (AreaAG+AreaBG)*QLT

Where:

Qpole	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached into
the volume of soil surrounding a transmission pole (8.09E-04 kg)

AreaAG	= 	Wood surface area above ground (5.5 m2 from Rohm and Haas,
2006)

AreaBG	= 	Wood surface area below ground (1.6 m2 from Rohm and Haas,
2006)

QLT	= 	Cumulative quantity of Diiodomethyl p-tolyl sulfone leached out
of 1 m2 of treated wood over a 14 day period (1.14E-04 kg/m2 from
Section 1.1)

Next, the concentration of Diiodomethyl p-tolyl sulfone in the soil
surrounding the transmission pole was calculated by dividing the
estimated quantity of Diiodomethyl p-tolyl sulfone leached into the soil
surrounding the transmission pole (Qpole) by the product of the volume
of wet soil and the bulk density of wet soil (Rohm and Haas, 2006).  A
conversion factor was used to convert kilograms to milligrams.  The
equation for this step is shown below (Equation 3.)

Equation 3:

 Csoilpole = (Qpole*CONVkgmg)/(Vsoil*RHOsoil)

Where: 

Csoilpole	= 	Estimated concentration of Diiodomethyl p-tolyl sulfone in
soil surrounding a transmission pole (1.98 mg/kg)

Qpole	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached into
the volume of soil surrounding a transmission pole (8.09E-04 kg from
Equation 2)

CONVkgmg	= 	Conversion factor from kilograms to milligrams (1.00E+6
mg/kg)

Vsoil	= 	Wet soil volume (0.24 m3 from Rohm and Haas, 2006)

RHOsoil	= 	Bulk density of wet soil (1,700 kgww/m3 from Rohm and Haas,
2006)

Fence Posts

Environmental concentrations of Diiodomethyl p-tolyl sulfone in soil
from treated fence posts were estimated by first calculating the
quantity of the Diiodomethyl p-tolyl sulfone leached into the volume of
the soil surrounding a fence post, as shown in Equation 4.  QFencePost
is the product of the sum of the wood surface area above and below
ground and the cumulative quantity of Diiodomethyl p-tolyl sulfone
leached per m2 of treated wood over a 14 day period (Rohm and Haas,
2006). 

Equation 4:

 QFencePost = (AreaAG+AreaBG)*QLT

Where:

QFencePost	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of soil surrounding a fence post (9.12E-05 kg)

AreaAG	= 	Wood surface area above ground (0.6 m2 from Rohm and Haas,
2006)

AreaBG	= 	Wood surface area below ground (0.2 m2 from Rohm and Haas,
2006)

QLT	= 	Cumulative quantity of Diiodomethyl p-tolyl sulfone leached from
1 m2 of treated wood over a 14 day period (1.14E-04 kg/m2 from Section
1.1)

Using Equation 5, the concentration of Diiodomethyl p-tolyl sulfone in
the soil surrounding the fence post was then calculated by dividing the
estimated quantity of Diiodomethyl p-tolyl sulfone leached into the soil
surrounding the fence post (QFencePost) by the product of the volume of
wet soil and the bulk density of wet soil (Rohm and Haas, 2006).  A
conversion factor was used to convert kilograms to milligrams.  

Equation 5:

 CsoilFencePost = (QFencePost*CONVkgmg)/(Vsoil*RHOsoil)

Where:

CsoilFencePost	= 	Estimated concentration of Diiodomethyl p-tolyl
sulfone in soil surrounding a fence post (1.09 mg/kg)

QFencePost	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of soil surrounding 

			a fence post (9.12E-05 kg from Equation 4)

CONVkgmg		= 	Conversion factor from kilograms to milligrams (1.00E+6
mg/kg)

Vsoil	= 	Wet soil volume (0.049 m3 from Rohm and Haas, 2006)

RHOsoil	= 	Bulk density of wet soil (1,700 kgww/m3 from Rohm and Haas,
2006)

Fence

The environmental concentration of Diiodomethyl p-tolyl sulfone in soil
following application to a fence was estimated by first calculating the
quantity of the Diiodomethyl p-tolyl sulfone leached into the volume of
the soil surrounding a one meter length of fence.  As shown in Equation
6, this value (QFence) is the product of the surface area of wood per
meter of fence and the cumulative quantity of Diiodomethyl p-tolyl
sulfone leached per m2 of treated wood over a 14 day period (Rohm and
Haas, 2006). 

Equation 6:

 

QFence = AreaFence*QLT

Where:

QFence	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of soil surrounding a one meter length of fence
(2.28E-04 kg)

AreaFence	= 	Wood surface area per meter of fence (2 m2 from Rohm and
Haas, 2006)

QLT	= 	Cumulative quantity of Diiodomethyl p-tolyl sulfone leached per
m2 of treated wood over a 14 day period (1.14E-04 kg/m2 from Section
1.1)

Using Equation 7, the concentration of Diiodomethyl p-tolyl sulfone in
the soil surrounding the fence was calculated by dividing the estimated
quantity of Diiodomethyl p-tolyl sulfone leached into the soil
surrounding the fence (QFence) by the product of the volume of wet soil
and the bulk density of wet soil (Rohm and Haas, 2006).  A conversion
factor was used to convert kilograms to milligrams.  

Equation 7: 

CsoilFence= (QFence*CONVkgmg)/(Vsoil*RHOsoil)

Where:

CsoilFence	= 	Estimated concentration of Diiodomethyl p-tolyl sulfone in
soil surrounding a 1 m length of fence (13.41 mg/kg)

QFence	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of soil surrounding the fence (2.28E-04 kg from Equation
6)

CONVkgmg	= 	Conversion factor from kilograms to milligrams (1.00E+6
mg/kg)

Vsoil	= 	Wet soil volume (0.01 m3 from Rohm and Haas, 2006)

RHOsoil	= 	Bulk density of wet soil (1,700 kgww/m3 from Rohm and Haas,
2006)

Deck Post

The concentration of Diiodomethyl p-tolyl sulfone in soil surrounding a
treated deck posts was estimated by first calculating the quantity of
the Diiodomethyl p-tolyl sulfone leached into the volume of the soil
surrounding a deck post.  As shown in Equation 8, this value (QDeckPost)
is the product of the sum of the surface area of treated wood above and
below ground and the cumulative quantity of Diiodomethyl p-tolyl sulfone
leached per m2 of treated wood over a 14 day period (Rohm and Haas,
2006). 

Equation 8:

 QDeckPost = (AreaAG+AreaBG)*QLT

Where:

QDeckPost	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of soil surrounding 

a deck post (1.37E-04 kg)

AreaAG	= 	Wood surface area above ground (0.9 m2 from Rohm and Haas,
2006)

AreaBG	= 	Wood surface area below ground (0.3 m2 from Rohm and Haas,
2006)

QLT	= 	Cumulative quantity of Diiodomethyl p-tolyl sulfone leached out
of 1 m2 of treated wood over a 14 day period (1.14E-04 kg/m2 from
Section 1.1)

Then, Equation 9 was used to calculate the concentration of Diiodomethyl
p-tolyl sulfone in the soil surrounding the deck post.  In Equation 9
the estimated quantity of Diiodomethyl p-tolyl sulfone leached into the
soil surrounding the deck posts (QDeckPost) is divided by the product of
the volume of wet soil and the bulk density of wet soil (Rohm and Haas,
2006).  A conversion factor was used to convert kilograms to milligrams.
 

Equation 9:

 

CSoilDeckPost = (QDeckPost*CONVkgmg)/(Vsoil*RHOsoil)

Where:

CsoilDeckPost	= 	Estimated concentration of Diiodomethyl p-tolyl sulfone
in soil surrounding a deck post (1.30 mg/kg)

QDeckPost	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of soil surrounding a deck post (1.37E-04 kg from
Equation 8)

CONVkgmg	= 	Conversion factor from kilograms to milligrams (1.00E+6
mg/kg)

Vsoil	= 	Wet soil volume (0.062 m3 from Rohm and Haas, 2006)

RHOsoil	= 	Bulk density of wet soil (1,700 kgww/m3 from Rohm and Haas,
2006)

Deck

The environmental concentration of Diiodomethyl p-tolyl sulfone in soil
associated with a treated deck was estimated by first calculating the
quantity of the Diiodomethyl p-tolyl sulfone leached into the volume of
the soil surrounding a deck.  As shown in Equation 10, QDeck is the
product of the wood surface area above the soil and the cumulative
quantity of Diiodomethyl p-tolyl sulfone leached from 1 m2 of treated
wood over a 14 day period (Rohm and Haas, 2006). 

Equation 10: 

QDeck = AreaDeck*QLT

Where:

QDeck	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached into
the volume of soil surrounding the deck (2.74E-03 kg)

AreaDeck	= 	Wood surface area above soil (24 m2 from Rohm and Haas,
2006)

QLT	= 	Cumulative quantity of Diiodomethyl p-tolyl sulfone leached per
m2 of treated wood over 	a 14 day period (1.14E-04 kg/m2 from Section
1.1)

The concentration of Diiodomethyl p-tolyl sulfone in the soil
surrounding the deck was then calculated with Equation 11, in which the
estimated quantity of Diiodomethyl p-tolyl sulfone leached into the soil
surrounding the deck (QDeck) is divided by the product of the volume of
wet soil and the bulk density of wet soil (Rohm and Haas, 2006).  A
conversion factor was used to convert kilograms to milligrams.  

Equation 11: 

CsoilDeck= (QDeck*CONVkgmg)/(Vsoil*RHOsoil)

Where:

CsoilDeck	= 	Estimated concentration of Diiodomethyl p-tolyl sulfone in
soil surrounding the deck (0.67 mg/kg)

QDeck	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached into
the volume of soil surrounding the deck (2.74E-03 kg from Equation 10)

CONVkgmg	= 	Conversion factor from kilograms to milligrams (1.00E+6
mg/kg)

Vsoil	= 	Wet soil volume (2.4 m3 from Rohm and Haas, 2006)

RHOsoil	= 	Bulk density of wet soil (1,700 kgww/m3 from Rohm and Haas,
2006)

House

The environmental concentrations of Diiodomethyl p-tolyl sulfone in soil
surrounding a treated, wood-clad house was estimated by first
calculating the quantity of the Diiodomethyl p-tolyl sulfone leached
into the volume of the soil surrounding a house.  This quantity, which
is estimated with Equation 12, is the product of the treated wood
surface area above the soil and the cumulative quantity of Diiodomethyl
p-tolyl sulfone leached per m2 of treated wood over a 14 day period
(Rohm and Haas, 2006). 

Equation 12:

QHouse = AreaHouse*QLT

Where:

QHouse	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached
into the volume of soil surrounding a house (1.43E-02 kg)

AreaHouse	= 	Wood surface area above soil (125 m2 from Rohm and Haas,
2006)

QLT	= 	Cumulative quantity of Diiodomethyl p-tolyl sulfone leached per
m2 of treated wood over 	a 14 day period (1.14E-04 kg/m2 from Section
1.1)

Then, the concentration of Diiodomethyl p-tolyl sulfone in the soil
surrounding the house was calculated (see Equation 13) by dividing the
estimated quantity of Diiodomethyl p-tolyl sulfone leached into the soil
surrounding the house (QHouse) by the product of the volume of wet soil
and the bulk density of wet soil (Rohm and Haas, 2006).  A conversion
factor was used to convert kilograms to milligrams.  

Equation 13: 

CsoilHouse = (QHouse*CONVkgmg)/(Vsoil*RHOsoil)

Where:

CsoilHouse	= 	Estimated concentration of Diiodomethyl p-tolyl sulfone in
soil surrounding the house (16.76 mg/kg)

QDeck	= 	Estimated quantity of Diiodomethyl p-tolyl sulfone leached into
the volume of soil surrounding the house (1.43E-02 kg from Equation 12)

CONVkgmg	= 	Conversion factor from kilograms to milligrams (1.00E+6
mg/kg)

Vsoil	= 	Wet soil volume (0.5 m3 from Rohm and Haas, 2006)

RHOsoil	= 	Bulk density of wet soil (1700 kgww/m3 from Rohm and Haas,
2006)

Soil concentrations calculated for the six use scenarios are summarized
in Table 1.

Table 1.  Summary of Estimated Environmental Concentrations of
Diiodomethyl p-tolyl sulfone in Soil for Six Use Scenarios

Diiodomethyl p-tolyl sulfone Use scenario	Diiodomethyl p-tolyl sulfone
Mass (ai) Leached into Soil Associated with Treated Wood Surface (kg)1
Diiodomethyl p-tolyl sulfone Concentration in Soil (mg/kg wet weight)2

Transmission Pole	8.09E-04	1.98

Fence Post	9.12E-05  	1.09

Fence	2.28E-04	13.41

Deck Post	1.37E-04	1.3

Deck	2.74E-03	0.67

House	1.43E-02	16.76

1 Diiodomethyl p-tolyl sulfone mass leached into soil associated with
treated wood surfaces is calculated with Equations 2, 4, 6, 8, 10, and
12.

2 Diiodomethyl p-tolyl sulfone mass leached into soil associated with
treated wood surfaces is calculated with Equations 3, 5, 7, 9, 11, and
13.



2.	Dissolved Surface Water and Sediment Pore Water Concentration
Modeling

EPA’s Express model was used to estimate concentrations of
Diiodomethyl p-tolyl sulfone in dissolved surface water and sediment
pore water.  The Express model was run for each of the six Diiodomethyl
p-tolyl sulfone use scenarios identified in Section 1.2, and the soil
compartment loading estimates from Section 1.2 were used to develop
Diiodomethyl p-tolyl sulfone loading inputs for the Express runs.

The Express model requires hectare-scale Diiodomethyl p-tolyl sulfone
loading from soil (kg Diiodomethyl p-tolyl sulfone per ha) as an input
value.  The hectare-scale loading rates are the amount of Diiodomethyl
p-tolyl sulfone released into the soil compartment in a one-hectare
area.  For all use scenarios, it was assumed that five treated wood
units (e.g., transmission poles, houses) are present per hectare. 
Therefore, the hectare-scale loadings were calculating by multiplying
the Diiodomethyl p-tolyl sulfone mass leached into soil per treated wood
unit (i.e., the middle column in Table 1) by five units per hectare. 
Table 2 shows the resulting Diiodomethyl p-tolyl sulfone loadings per
hectare.

  Additional inputs for the Express runs include various
chemical-specific properties and assumptions.  Table 3 lists the inputs
to the Express runs, including input values, units, and information
sources.    

Express calculates multiple-year chemical concentrations in the water
and benthic sediments, which are then reported, for each year, the
single-day peak concentration, the maximum 24-hour, 96-hour, 21-day,
60-day, and 90-day mean concentrations, and the mean annual
concentration (EPA, 2006).  Model outputs display the upper 10
percentiles of the single-year results (e.g., the upper tenth percentile
of the mean annual concentrations).

Table 2.  Calculation of Diiodomethyl p-tolyl sulfone Loading Rates in
Soil per Hectare 

Soil Loading	Diiodomethyl p-tolyl sulfone Use Scenario

	Transmission Pole	Fence Post	Fence	Deck Post	Deck	House

Diiodomethyl p-tolyl sulfone Mass Leached into Soil Associated One Unit
of Treated Wood Surface (kg)	8.09E-04	9.12E-05	2.28E-04	1.37E-04
2.74E-03	1.43E-02

Diiodomethyl p-tolyl sulfone Mass Loading per Hectare (kg/ha)1	4.05E-03
4.56E-04	1.14E-03	6.85E-04	1.37E-02	7.15E-02

1 Mass loadings per hectare equal the Diiodomethyl p-tolyl sulfone mass
leached into soil per unit (e.g., transmission pole) times five units
per hectare.



Table 3. Express Model Inputs

Parameter	Value	Units	Source

OPP/EFED Scenario: Mississippi cotton scenario	MLRA 134	 	Rohm and
Haas, 2006

Molecular weight	422.02	g/mole	EPA, 2007

Vapor pressure	8.70E-07	mm Hg	EPA, 2007

Solubility	8.70E-02	mg/L	EPA, 2007

Soil Partition Coefficient (Koc)	615	ml/g	EPA, 2007

Aerobic soil metabolism	1.5	days	EPA, 2007

Aerobic aquatic metabolism	9.6	days	No data, used anaerobic aquatic
metabolism

Anaerobic aquatic metabolism	9.6	days	EPA, 2007

Hydrolysis test temperature	25	° Celsius	No data, Express default

Hydrolysis half life (pH 5)	4560	days	EPA, 2007

Hydrolysis half life (pH 7)	2.1	days	EPA, 2007

Hydrolysis half life (pH 9)	9.6	days	EPA, 2007

Aquatic direct photolysis	0, 10, 100	days	No data, three analyses with
three distinct values generated identical results.  Therefore, the
uncertainty associated with this parameter does not significantly affect
the results.

Sediment Partition Coefficient (Koc)	615	mg/L	No data, used Soil Koc

Number of applications	1	NA	Rohm and Haas, 2006

Application timing	Relative to emergence	NA	Rohm and Haas, 2006

Application method	Ground sprayer	NA	Rohm and Haas, 2006

Days relative to emergence	-1	days	No data, Express default

Chemical application model (CAM: Specifies method of pesticide
application to soil or foliage)	1	NA	Rohm and Haas, 2006

Application rate	See Table 2	kg/ha	See Equation 15

The results of the Express model runs for Diiodomethyl p-tolyl sulfone
are presented in Tables 4 and 5.  Table 4 show surface water
concentrations in µg/L and Table 5 shows sediment pore water
concentrations in µg/L.

Table 4. 10th Percentile Estimated Environmental Concentrations of
Diiodomethyl p-tolyl sulfone in Surface Water (µg/L) from Runoff as a
Consequence of Leaching from Treated Wood

Use scenario	Instantaneous	96-Hour (µg/L)	21-Day (µg/L)	60-Day (µg/L)
90-Day (µg/L)	Annual (µg/L)

Transmission Pole	7.10E-03	4.58E-03	1.59E-03	5.66E-04	3.77E-04	9.31E-05



Fence Post

	8.87E-04	5.72E-04	1.99E-04	7.07E-05	4.72E-05	1.17E-05



Fence

	1.96E-03	1.26E-03	4.38E-04	1.56E-04	1.04E-05	2.56E-05



Deck Post

	1.25E-03	8.01E-04	2.78E-04	9.90E-05	6.60E-05	1.63E-05



Deck

	2.43E-02	1.57E-02	5.45E-03	1.94E-03	1.29E-03	3.18E-04



House

	1.27E-01	8.15E-02	2.83E-02	1.01E-02	6.72E-03	1.66E-03



Table 5. 10th Percentile Estimated Environmental Concentrations of
Diiodomethyl p-tolyl sulfone in Sediment Pore Water (µg/L) from Runoff
as a Consequence of Leaching from Treated Wood

Use scenario	Instantaneous	96-Hour (µg/L)	21-Day (µg/L)	60-Day (µg/L)
90-Day (µg/L)	Annual (µg/L)



Transmission Pole	6.50E-04	6.42E-04	4.83E-04	2.19E-04	1.48E-04	3.64E-05



Fence Post

	8.13E-05	8.01E-05	6.03E-05	2.75E-05	1.84E-05	4.55E-06



Fence

	1.79E-04	1.76E-04	1.32E-04	6.04E-05	4.05E-05	1.00E-05



Deck Post

	1.14E-04	1.12E-04	8.44E-05	3.85E-05	2.58E-05	6.37E-06

Deck

	2.23E-03	2.20E-03	1.65E-03	7.53E-04	5.06E-04	1.25E-04



House

	1.16E-02	1.14E-02	8.59E-03	3.91E-03	2.63E-03	6.48E-04



3.	Assumptions/Limitations

Because wood leaching studies are not available for Diiodomethyl p-tolyl
sulfone, the cumulative release of Diiodomethyl p-tolyl sulfone from
treated wood was derived using a method developed by Krahn and Strub
(1990) which estimates leaching from wood treated with antisapstain
chemicals.  This methodology simulates leaching of Diiodomethyl p-tolyl
sulfone from treated wood exposed to rainfall.

The methodology used to simulate Diiodomethyl p-tolyl sulfone leaching
from treated wood (Krahn and Strub, 1990) uses the chemical uptake for
another antisapstain chemical, Busan, reported by Aschacher and
Grundlinger (2000).  This value may over- or under-estimate the uptake
rate for Diiodomethyl p-tolyl sulfone due to differences in
chemical-specific properties and experimental conditions (e.g.,
application method or environmental conditions).  

This methodology does not address a number of physical and environmental
variables (e.g., chemical formulation, wood surface texture, ambient
temperature, soil type, soil moisture, and soil pH) that may affect the
release of Diiodomethyl p-tolyl sulfone from treated wood and subsequent
movement in environmental media.  In addition, the methodology does not
address chemical or biological degradation. 

This analysis uses assumptions about the surface areas of wood treated
for six Diiodomethyl p-tolyl sulfone use scenarios, as well as
assumptions about the number of treated surfaces per hectare.  These
assumptions, which were obtained from Rohm and Haas (2006) may over- or
under-estimate the potential for Diiodomethyl p-tolyl sulfone releases
to soil associated with the six scenarios.  

The methodology includes an assumption that soil, surface water, and
sediment pore water concentrations are affected by only one of the six
Diiodomethyl p-tolyl sulfone use scenarios at a time.

The Express model estimates concentrations in sediment pore water. 
Concentrations of Diiodomethyl p-tolyl sulfone adsorbed to sediment are
not calculated.

The Express analyses for both dissolved surface water and sediment pore
water were limited due to unavailable data for the following inputs:
aerobic aquatic metabolism, hydrolysis test temperature, aquatic direct
photolysis, and sediment Koc.  Assumption and approaches used to address
these uncertainties are shown below:

The anaerobic aquatic metabolism (9.6 days) was used in place of the
aerobic aquatic metabolism.  

The Express default of 25° Celsius was used for the hydrolysis test
temperature.

Analyses were run using values of 0, 10, and 100 days for aquatic direct
photolysis and yielded identical dissolved surface water and sediment
pore water concentrations for all use scenarios.  Therefore, this
uncertainty was determined not to significantly affect the results of
the analysis.

The soil Koc (615 mL/g) was used in place of the sediment Koc.

4.	References

Aschacher G. and Gruendlinger R., 2000.  Methods to evaluate the
ecotoxicological risks of anti-sapstain preservatives.  Holzforschung,
Austria Research and Development. 
www.holzforschung.at/english/img_eng/ascha200.pdf.

Carbone, J. and Jacobson, A.. 2006. Environmental risk assessment of
DCOIT for wood preservative applications. Report # 06R-1006. Rohm and
Haas Company. 9 February 2006.

EPA, 2007.  “Amical Environmental Fate Data Based on Jim Breithaupt
Power Point Presentation,” document provided by Siroos Mostaghimi,
U.S. Environmental Protection Agency, October 4, 2007.

EPA, 2006.  “User Manual for EXPRESS, the EXAMS-PRZM Exposure
Simulation Shell, Version 1.03.02.”  Prepared by Lawrence A. Burns,
National Exposure Research Laboratory, U.S. Environmental Protection
Agency, Athens, GA.  EPA/600/R-06/095.  September 2006.

EPA, 2007.  Exposure Assessment for the use of AMICAL ((Benzene, 1-
(diiodomethyl)sulfonyl)-4-methyl ) on  Heating, Ventilation, and Air
Conditioning Systems” 

 Memorandum from Siroos Mostaghimi to Norm Cook, October 22, 2007.

Krahn, P. and Strub R. 1990. Standard leaching test for antisapstain
chemicals: Regional Program Report 90-10. Environment Canada.
Conservation and Protection, Pacific and Yukon Region North Vancouver,
BC. 1990.

Rohm and Haas, 2006.  Environmental Risk Assessment of DCOIT for Wood
Preservative Applications.  Prepared by John P Carbone and Andrew H.
Jacobson, Rohm and Haas Company, Spring House, PA.  Company Report
06R-1006.  February 9, 2006.

Williams, M. and Bradley, A., 1996. Aqueous Availability of AMICAL 48:
Final Report: Lab Project Number: 42782: ABC 42782.  Unpublished study
prepared by ABC Laboratories Europe, Ltd. 78 p.  MRID 43997001.

Versar, 2005. "ADBAC Antisapstain Modeling (TAF 1-4-10, CM-43),"
memorandum to Najm Shamim, U.S. EPA, from Ron Lee and Jignasha Patel,
Versar, Inc., December 5, 2005.

 Note that in the antisapstain leachate analysis for ADBAC (Versar
2005), the height and width of the lumber stack assumed by Krahn and
Strub (1990) were reversed resulting in incorrect SAtop, SAtotal values.
 The correct values are used in this analysis. 

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