APPENDIX A 

STANDARD FORMULAS, Exposure Data,   TC \l1 "

Appendix B:  Occupational Handler Exposure Data and Risk Calculations
FOR OCCUPATIONAL AND RESIDENTIAL EXPOSURES TO Mefluidide

  SEQ CHAPTER \h \r 1 APPENDIX A -1

STANDARD FORMULAS USED FOR 

CALCULATING 

OCCUPATIONAL AND RESIDENTIAL 

EXPOSURES TO Mefluidide

A.  Introduction

This document is a summary of the formulas used to calculate
occupational and residential exposures to mefluidide.   These formulas
and a basic description of how they are used were taken from References
A through E.  These references also contain more detailed information on
the rationale behind these formulas.  

B.  Occupational Handler/Applicator Exposures

	The basic rationale for these formulas is that the daily exposure is
the product of the amount of active ingredient (a.i.) handled per day
times a unit exposure value.  The amount of ai handled per day is the
product of the application rate times the area treated.  For example, if
1.0 lb/acre of MEFLUIDIDE were applied to 80 acres in one day, the
amount of mefluidide handled that day would be 80 lbs.  The unit
exposure value is the amount of exposure that results from handling a
given amount of active ingredient by a certain method while using
certain PPE.  For example, the inhalation unit exposure value for open
mixing and loading of liquids is 1.0 ug per pound of ai handled.  In
this example, the daily exposure would be 80 lbs ai handled times 1.0 ug
unit exposure per pound of ai handled which equals 80 ug per day.  The
daily absorbed dose (mg/kg BW) is calculated from the exposure by
converting the exposure from ug into mg, multiplying the exposures times
an absorption factor (usually 1.0 for inhalation) and dividing the
result by the body weight (70 kg).  In this example the daily dose is
(80 ug/day * 0.001 mg/ug *1.0)/70 kg which equals 0.0011 mg/kg/day.

Daily inhalation exposure is calculated:

Daily inhalation exposure = Unit exposure x Application rate x Area
Treated x Conversion Factor (1.0E-3)                        (mg/kg/day) 
                                                                        
                           

Where:

Unit exposure	=	(ug/lb ai handled) derived from PHED or ORETF Study Data

Application rate	=	lb ai per acre or gallon of spray solution; and

Daily treatment	=	acres or gallons applied per day).

Absorbed Daily Dose is calculated:

Absorbed daily inhalation dose = (Daily  inhalation exposure x
absorption factor) / body weight

(mg/kg/day)                                     (mg/day)                
                    (unitless)               (kg)

[Note: an absorption factor of 1.0 was used for inhalation exposures.]

	Once the absorbed daily doses are calculated, the Margins of Exposure
(MOEs) can be calculated as shown below:

Margin of Exposure is calculated:

MOE (unitless)  =   NOAEL (mg/kg/day)  /  Dose (mg/kg/day)

	The target MOE is 100 for occupational handlers. Scenarios with MOEs
greater than the target MOEs do not exceed the Agency’s level of
concern. 

C.  Residential Handler Exposures

	Residential handler exposures are calculated in the same manner as
described above for occupational handlers, however, there are a few
differences in the assumptions used.   These differences are described
in References B and C and include the following:

*PPE such as respirators are not worn.

*The areas treated are much smaller.

D.  Residential Post Application Exposure on Treated Turf

	

	The SOPs For Residential Exposure Assessment (Reference B) define three
incidental oral pathways that apply to post application toddler exposure
on treated turf.  The SOPs and the associated pathways are presented
below:

∙	Dose from hand-to-mouth activity from treated turf calculated using
SOP 2.3.2:  

	Residues ingested from a child touching turf and then putting their
hands in their mouth.

∙	Dose from object-to-mouth activity from treated turf calculated
using SOP 2.3.3:  

	Residues ingested from a child mouthing a handful of treated turf); and

∙	Dose from soil ingestion activity from treated turf calculated using
SOP 2.3.4:  

	Residues from a child touching treated soil and then putting their
hands in their mouth.

	 

	The algorithms used for each type of dose calculation are presented on
the following pages. 

	

Exposures from Hand to Mouth Behavior on Treated Turf: 

The following formula is used to calculate the incidental oral ingestion
exposures from to hand-to-mouth behavior on treated turf (SOP 2.3.2). 

			

PDR = TTR * (SE/100) * SA * Freq * Hours * (1 mg/1000 ug)

	where:

	

PDR		=	potential dose rate from hand-to-mouth activity (mg/day);

TTR		=	Turf Transferable Residue (µg/cm2);

SE		=	saliva extraction factor (50%);

SA		=	surface area of the hands (20 cm2);

Freq		=	frequency of hand-to-mouth events (20 events/hour); and

Hours	=	exposure duration (2 hours).

	When used for hand to mouth exposures, the TTR value is based upon the
default assumption of 5 percent of the application rate and not the TTR
study .

The formula for calculating the Day 0 TTR value is given below:

TTR = 	Application Rate * F * CF1 * CF2 * CF3

Where:

Application Rate	=	lbs ai/acre 	

F			= 	fraction of applied ai that is available for hand to mouth
exposure (5 percent)

CF1			= 	1.0 lb ai/acre equals 2.3 x 10-5 lbs ai per ft2

CF2			= 	4.54 x 108 ug/lb

CF3			= 	0.00108 ft2/cm2

Note:  CF1 * CF2 * CF3 = 11.23

Exposures from Object to Mouth Behaviors on Treated Turf

The following formula is used to calculate exposures from
object-to-mouth behavior on treated turf that is represented by a child
mouthing on a handful of turf (SOP 2.3.3):

PDR = TTR * IGR * (1mg/1000ug)

where:

PDR		=	potential dose rate from mouthing activity (mg/day);

TTR		=	Turf Transferable Residue where dissipation is based on TTR study
and the 0-day value is based on the 20% initial transferability factor
(µg/cm2); and

IgR		=	ingestion rate for mouthing of grass per day (25 cm2/day).

When used for object to mouth exposures, the TTR value is based upon the
default assumption of 20 percent of the application rate .



Exposures from Soil Ingestion on Treated Turf

	The following formula is used to calculate exposures from soil
ingestion (SOP 2.3.4):

PDR = SR * IgR * (0.000001 gm/ 1 ug)

Where:		

PDR	=	dose from soil ingestion activity (mg/day)

SR	=	Soil Residue where dissipation is based on TTR study and the 0-day
value is based on the application rate, 1 cm depth of surface soil, and
the density of soil (µg/cm3)

IgR	=	ingestion rate for daily soil ingestion (mg/day)

Where:

SR	=	Application rate * F*11.23*CF4

Where 

F = Faction of ai available in the uppermost cm of soil (100%/cm)

1.0 lbs/acre = 11.23 µg/cm2

CF4 = Volume to weight unit conversion factor to convert the volume
units (cm3) to weight units for the SR value (0.67 cm3/g soil)

MOE Calculations for Each Pathway

The MOEs are calculated for each individual pathway using the MOE
formula:

MOE  =   NOAIL (mg/kg/day / Dose (mg/kg/day)

MOEs Calculations for All of the Pathways Combined	

The dose from each incidental oral pathway was combined into a total
dose as shown below.

Total Dose = (Hand-to Mouth Dose + Object to Mouth Dose + Soil Ingestion
Dose)

The total dose is then used to calculate an MOE as shown above. The
target MOE is 100.

References

	PHED Surrogate Exposure Guide, V1.1.  Health Effects Division, Office
of Pesticide Program. August, 1998.

	Standard Operating Procedures for Residential Exposure Assessments. 
U.S. EPA.   December 18, 1997.

	ExpoSAC SOP #12 “Recommended Revisions to the Standard Operating
Procedures (SOPs) for Residential Exposure Assessments.  February 22,
2001

	Series 875 - Occupational and Residential Exposure Test Guidelines,
Group B - Post Application Exposure Monitoring Test Guidelines.  U.S.
EPA.   February 10, 1998.

	Overview of Issues Related to the Standard Operating Procedures for
Residential Exposure Assessment, Presented to the FIFRA Scientific
Advisory Panel on September 1999

  SEQ CHAPTER \h \r 1 Appendix A-2:  Occupational Handler Exposure Data
 TC \l1 "

Appendix B:  Occupational Handler Exposure Data 

and Risk Calculations for Mefluidide

Table A-1.  Mefluidide Formulations Used, Application Methods,
Application Rates and Daily Amounts Treated

Application Method	Use Sites	Formulations Used

	Application  Rate1

(lb ai/acre or lb ai/ga)	Daily Amount Treated or Applied2

Mixer/Loader (Turfgun)	Turf	Liquid	1.0 lbs ai/acre	100 acres/day3

Mixer/Loader (High pressure handwand)	Ornamental trees	Liquid	0.01 lbs
ai/gallon	1000 gallons/day

Mixer/Loader (Groundboom)	Golf course	Liquid	1.0 lbs ai/acre	40
acres/day

Mixer/Loader (ROW spray)	Right of way	Liquid	0.067 lbs ai/gallon	1000
gallons/day

Applicator (Groundboom Spray )	Golf Course Turf	Liquid	1.0 lb ai/acre	40
acres/day

Applicator (Right of Way Spray)	Non-Turf Areas	Liquid	0.067 lbs
ai/gallon	1000 gallons/day

Applicator (Turfgun)	PCO Turf Areas	Liquid	1.0 lb ai/acre	5 acres/day

 Mix/Load/Apply (Turfgun)	PCO Turf Areas	Liquid	1.0 lb ai/acre	5
acres/day

Mix/Load/Apply (Backpack Sprayer)	Non Turf areas	Liquid	0.067 lbs
ai/gallon	40 gallons/day

Load/Apply (Push Cyclone )	PCO Turf	Granular	0.5 lb ai/acre	5 acres/day



Notes				

1.    Application rates are from Table 1.4.  

2.	Except as noted, these values are from ExpoSAC Policy 9 “Standard
Values for Daily Acres Treated in Agriculture”, Revised 7/5/2000.

3.	Based upon a mixer loader at a central location supporting a PCO crew
of 20 applicators.



Table A-2.   Exposure Data Used for Mefluidide Occupational
Handler/Applicator Risk Assessment

Exposure Scenarios (See notes for PPE Descriptions)	Baseline Dermal
(mg/lb ai)	Baseline Inhalation (ug/lb ai)	Single Layer Dermal 

(mg/lb ai)	Double Layer Dermal 

(mg/lb ai) 	PF5 Respirator Inhalation (ug/lb ai)	PF10 Respirator
Inhalation (ug/lb ai)	Engineering Control Dermal (mg/lb ai)	Engineering
Control Inhalation (ug/lb ai) 

Mixer Loader Unit Exposure Values

Mix/Load Liquid Formulations 	2.9	1.2	0.023	0.017	0.24	0.12	0.0086	0.083

Applicator Unit Exposure Values

Groundboom Application  

Right of Way (ROW) Application 

Turf Gun Application 	0.014

1.3

No Data 	0.74

3.9

1.0	0.014

6.1

0.73	0.011

ND

0.40	0.15

10.8

0.20	0.074

5.4

0.10	0.005

NA

NA	0.043

NA

NA

Mixer/Loader/Applicator Unit Exposure Values

Mix/Load/Apply Liquid Flowables with a Turfgun 

Mix/Load/Apply Liquids with Backpack Sprayer

Load/Apply Granules with a Push Cyclone Spreader	No Data

No Data

0.35	1.9

30

7.5	0.5

2.5

0.22	0.27

1.6

0.11	0.38

6.0

1.5	0.19

3.0

0.75	N/Feasible

N/Feasible

N/Feasible	Not Feasible

Not Feasible

Not Feasible



Notes - PPE Descriptions

Badeline dermal and inhalation unit exposure values are from PHED.

Baseline Dermal - includes long sleeve shirts, long pants, shoes and
socks.

Single Layer Dermal  - includes water resistant gloves over Baseline PPE

Double Layer Dermal - includes Tyvek or cotton coveralls over Single
Layer PPE

PF5 Respirator Inhalation -  filtering facepiece disposable respirator
(i.e. dustmask) with a protection factor of 5

PF10 Respirator Inhalation - half face cartridge respirator with a
protection factor of 10



Table A-3.  Sources of Exposure Data Used for Mefluidide Occupational
Handler Exposure and Risk Calculations

Exposure Scenario 	Data Source	Comments2, 3

Mixer/Loader

Mix/Load  Liquid Formulations 

	PHED 1	Baseline: Hands, dermal, and inhalation = acceptable grades.
Hands = 53 replicates; Dermal = 72 to 122 replicates; and Inhalation =
85 replicates.  High confidence in hand, dermal, and inhalation data. No
protection factor was needed to define the unit exposures.

PPE: The same dermal data are used as for baseline coupled with a 50%
protection factor to account for an additional layer of clothing.  Hands
= acceptable grades.  Hands = 59 replicates.  High confidence in hand
data.  A respirator protection factor of 5 is applied to estimate the
use of a dust mask.  A respirator protection factor of 10 is applied to
estimate the use of a half-face respirator.

Engineering Controls:  Hands, dermal, and inhalation = acceptable
grades. Hands = 31 replicates; Dermal = 16 to 22 replicates; and
Inhalation = 27 replicates.  High confidence in hand, dermal, and
inhalation data. 

Applicator

 Groundboom Application 	PHED1	Baseline: Hand, dermal, and inhalation =
acceptable grades.  Hands =29 replicates, dermal = 23 to 42 replicates,
and inhalation = 22 replicates. High confidence in hand, dermal, and
inhalation data. No protection factors were needed to define the unit
exposure values.

PPE: The same dermal data are used as for baseline coupled with a 50%
protection factor to account for an additional layer of clothing. Hands
= ABC grades. Hands = 21 replicates. Medium  confidence in hand data.  A
respirator protection factor of 5 is applied to estimate the use of a
dust mask.  A respirator protection factor of 10 is applied to estimate
the use of a half-face respirator.

Engineering Controls: Hand and dermal = ABC grade. Inhalation =
acceptable grades.  Hands = 16 replicates; dermal = 20 to 31 replicates;
and inhalation = 16 replicates. Medium confidence in the hand and dermal
data.  High confidence in inhalation data.  No protection factor  needed
to define the unit exposure value.  Protective gloves not used.

Right of Way Sprayer Application 	PHED Right of Way Sprayer Data
Baseline:  Hands = 16 replicates with ABC grade data, dermal = 4 to 20
replicates with ABC grade data, and inhalation = 16 replicates with AB
grade data.  Low confidence due to lack of dermal replicates.   No
protection factor was needed to define the unit exposure value.

PPE:   Hands = 4 replicates with AB grade data, dermal = 4 to 20
replicates with ABC grade data.   The same dermal data are used as for
baseline coupled with a 50% protection factor to account for an
additional layer of clothing.  Low confidence due to low number of
dermal and hand replicates.  A respirator protection factor of 5 is
applied to estimate the use of a dust mask.  A respirator protection
factor of 10 is applied to estimate the use of a half-face respirator.

Engineering Controls: No data is available.

Turfgun Application 	ORETF

OMA002	Baseline: No ungloved data

PPE: Dermal and hands = B grade; Inhalation = B grade; Dermal = 10
replicates; hands = 10 replicates; and inhalation = 10 replicates. 
Medium  confidence in inhalation, dermal, and hand data due to low
number of replicates.  A 50% protection factor to account for an
additional layer of clothing. A respirator protection factor of 5 is
applied to estimate the use of a dust mask.  A respirator protection
factor of 10 is applied to estimate the use of a half-face respirator.

Engineering Controls: Not considered feasible for this exposure
scenario.

Mixer/Loader/Applicator (M/L/A)

M/L/A Liquids with a Turfgun	ORETF OMA002	Baseline: No ungloved data

PPE: Dermal and hands = B grade with 15 replicates; Inhalation = B grade
with 15 replicates.  High confidence in inhalation, dermal, and hand
data.  A 50% protection factor to account for an additional layer of
clothing. A respirator protection factor of 5 is applied to estimate the
use of a dust mask.  A respirator protection factor of 10 is applied to
estimate the use of a half-face respirator.

Engineering Controls: Not considered feasible for this exposure
scenario.

M/L/A Liquids with a Backpack Sprayer 	PHED1	Baseline: No Data

PPE: Hands = C grades. Hands = 11 replicates.  Low confidence in hand
data. The same dermal data are used as for baseline coupled with a 50%
protection factor to account for an additional layer of clothing.  A
respirator protection factor of 5 is applied to estimate the use of a
dust mask.    A respirator protection factor of 10 is applied to
estimate the use of a half-face respirator.   

Engineering Controls: Not considered feasible for this exposure
scenario.

Load/Apply Granules with a Push Cyclone Spreader 	ORETF

OMA001	Baseline: Dermal and ungloved hands = AB grade with 20
replicates; Inhalation = AB grade with 40 replicates.  High confidence
in inhalation, dermal, and hand data.

PPE: Dermal and gloved hands = AB grade with 20 replicates; High
confidence in dermal, and hand data.  A 50% protection factor to account
for an additional layer of clothing. A respirator protection factor of 5
is applied to baseline inhalation data to estimate the use of a dust
mask.  A respirator protection factor of 10 is applied to estimate the
use of a half-face respirator.

Engineering Controls: Not considered feasible for this exposure
scenario.



Notes

	PHED refers to the Pesticide Handler Exposure Database Version 1.1 PHED
Surrogate Exposure Guide of August 1998

	The data grade and confidence categories are assigned as follows:

	Grade A data	= Lab recovery is 90 to 110 percent with a CV <15.  Field
recovery is 70 to 120 percent.  Storage stability data are optional.

	Grade B data	= Lab recovery is 80 to 110 percent with a CV <25.  Field
recovery is 50 to 120 percent.  Storage stability data are optional.

	Grade C data	= Lab recovery is 70 to 120 percent with a CV <33.  Field
recovery is 30 to 120 percent or is missing.  Storage stability data is
50 to 120 percent

	Grade D data	= Lab recovery is 60 to 120 percent with a CV <33.  Field
recovery and storage stability data are optional. 

	Grade E data	= Does not meet above criteria.

	High Confidence	= grade A and B data and 15 or more replicates per body
part

	Medium Confidence	= grade A, B, and C data and 15 or more replicates
per body part

	Low Confidence	= grade A, B, C, D and E data or any combination of
grades with less than 15 replicates.

∙	PHED grading criteria only affect one aspect of the exposure
assessment.  The other exposure factors should also be considered in the
risk management decision.



Table A-4.  Exposure Factors and Formulas Used for Mefluidide



Exposure Factors	Formulas

Inhalation Absorption = 100 percent	Daily Exposure = Application Rate *
Area treated or amount applied* Unit Exposure Value

NOAIL for Short/Intermediate/Long Term Inhalation Exposures = 35
mg/kg/day 

(based upon the same study used for dermal exposures)	Daily Dose =
(Daily Exposure * Absorption factor)/Body Weight

Body Weight = 70 kg	MOE = NOAEL/Daily Dose



  SEQ CHAPTER \h \r 1 Appendix A-3: Residential  Handler Exposure Data

and Risk Calculations for Mefluidide

Table A-5.  Unit Exposure Data for Mefluidide Residential Exposure
Assessment

Scenario	Data Source	Unit Exposure Values

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Notes for Table 3

1	This study involved the application of granular and liquid
formulations of Dacthal to residential lawns.  It was reviewed by Health
Canada and Gary Bangs in Document #D261948.

2	This study involved the application of liquid carbaryl to home garden
vegetables.  It was reviewed by Jeff Dawson in Document
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