UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

Date: September 15, 2015 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJECT: Tcrbufos. Acute and Steady State Aggregate Dietary Exposure and Risk Assessment of 

Food and Drinking Water to Support Registration Review. 

PC Code: 105001 DP Barcodc: 0422672 

Decision No.: ~72CJL// Registration No.: 5481-545 & 5481-547 

Petition No.: NA Rc2ulatory Action: Registration Review 

Risk Assessment Type: Dietary Case No.: 27605 

TXR No.: NA CAS No.: 13071-79-9 

M RID No.: None 40 CFR: § 180.352 

FROM: Peter 

Risk Assessment 

Savoia, Chemist 

Branch 

Q-fcJ'._

V 

- L~~ 

THRU: 

TO: 

Health Effects Division (7509P) 

Michael S. Metzger, Branch Chief I J (} J) Risk Assessment Branch V J/~' V 

1 ~ {-/ 

Health Effects Division (7509P) ~ 

Thurston

Sheila Pip

. Morton

er, Chem

And , Chemist 

ist Sl .t 

~ - r'1' 

Dietary Exposure Scie~~Advisory Council 

Health Effects Division (7509P) 

Matthew Lloyd, Risk Assessor 

Risk Assessment Branch V N II 

Health Effects Division (7509P) 

And 

Matthew Manupclla, Risk Manager Reviewer 

Risk Management and Implementation Branch II 

Pesticide Re-Evaluation Division (7508P) 

Executive Summary 

Acute and steady state (acute 2-day average) aggregate food and drinking water dietary exposure and 

risk assessments for terbufos were conducted using the Dietary Exposure Evaluation Model software 

with the Food Commodity Intake Database (DEEM-FCID) Version 3. 16. This software uses 2003-

2008 food consumption data from the U.S. Department of Agriculture's (USDA's) National Health 

and Nutrition Examination Survey/What We Eat in America, (NHANES/WWEJA). These analyses 

reflect the latest consumption data which are being made to support the registration review risk 

assessment ofterbufos. This memorandum was reviewed by two peer reviewers of the DESAC (and 

Page I of 44 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 2 of 44

the entire DESAC on 10/02/2014), per DESAC Standard Operating Procedures (SOP) 2012.1. 

Acute Dietary (Food and Water) Exposure Results and Characterization

Terbufos is an organophosphate (OP) insecticide that is marketed in closed loading systems as 

granular products intended for use in agriculture as a soil incorporated insecticide. It is used to 

control a variety of pests which affect bananas, coffee, corn, sugar beets, and sorghum. Terbufos is 

typically applied at planting with concurrent soil incorporation using ground based application 

equipment, but can also be applied at post-emergence or during cultivation activities. 

An unrefined acute dietary exposure assessment was conducted to estimate the dietary exposure and 

risk for registration review. The acute dietary exposure assessment was conducted using field trial 

residues and 100% crop treated data. The distribution of drinking water concentrations was based on 

the maximum use rate (max rate) of terbufos from the Texas sorghum application scenario.

The acute aggregate dietary exposure estimates are above HED’s level of concern (>100%) for the 

acute population adjusted dose (aPAD) for the U.S. population and all population subgroups. 

Combined dietary exposure for the U.S. population from food and drinking water (max rate) is 

1900% of the aPAD with an exposure of 0.000389 mg/kg/day at the 95th percentile. The most highly 

exposed population subgroup is all infants (<1 year old) having an estimate of 5300% of the aPAD

with an exposure of 0.001055 mg/kg/day at the 95th percentile.

Steady-State Dietary (Food and Drinking Water) Exposure Results and Characterization

OP insecticide active ingredients can exhibit a phenomenon known as “steady-state”

acetylcholinesterase (AChE) inhibition which is the most sensitive endpoint for all lifestages. After 

repeated dosing at the same level, the amount of AChE inhibition in a given dose remains consistent 

across duration. For this reason, a steady-state point of departure (PoD) was selected for oral 

exposure to terbufos (Table 4).

 

An unrefined steady-state dietary exposure assessment was conducted to estimate the dietary risks 

associated with the registration of terbufos. For this analysis, the DEEM acute module is used to 

conduct a 2-day average assessment of the OP active ingredient using the steady-state PoD, 2-day 

average food consumptions, and 21-day forward rolling drinking water averages. These 2-day 

average assessments provide an estimate of 21-day (“steady-state”) average daily food and drinking 

water exposures. The steady-state exposure assessment was also conducted using field trial residues 

and 100% crop treated data. The distribution of drinking water concentrations is calculated as a 21-

day forward rolling average based on the maximum use rate of terbufos from the Texas sorghum 

application scenario.

The resulting steady-state (ss) aggregate dietary exposures are all above HED’s level of concern 

(>100%) of the ssPAD for the U.S. population and all population subgroups. Combined dietary 

exposure for the U.S. population from food and drinking water (max rate) is 3800% of the ssPAD 

with an exposure of 0.000380 mg/kg/day at the 95th percentile. The most highly exposed population 

subgroup is all infants (<1 year old) having an estimate of >10000% of the ssPAD with an exposure 

of 0.001038 mg/kg/day at the 95th percentile.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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Cancer Dietary (Food and Drinking Water) Exposure Result and Characterization

A cancer dietary exposure and risk assessment was not conducted for terbufos since it is classified as 

“not likely to pose a carcinogenic hazard to humans”.

I. Introduction

Dietary risk assessment incorporates both exposure and toxicity of a given pesticide. For the acute 

and steady state (acute 2-day average) assessments, the risk is expressed as a percentage of a 

maximum acceptable dose (i.e., the dose that HED has concluded will result in no unreasonable 

adverse health effects). This dose is referred to as the population adjusted dose (PAD). The PAD is 

equivalent to the point of departure (PoD, NOAEL, LOAEL, e.g.) divided by the required uncertainty 

or safety factors.

For the acute and steady state (acute 2-day average) assessments, HED is concerned when estimated 

dietary risk exceeds 100% of the PAD. References that discuss dietary risk assessments in more 

detail are available on the EPA/pesticides web site: “Available Information on Assessing Exposure 

from Pesticides, A User’s Guide,” 21-JUN-2000, web link: 

http://www.regulation.gov/#!documentDetail;D=EPA-HQ-OPP-2007-0780-0001; or see SOP 99.6 

(20-AUG-1999).

For the OP insecticide terbufos, HED has conducted unrefined acute and steady-state (acute 2-day 

average) dietary risk assessments using DEEM-FCID Version 3.16 modeling software. OPs exhibit a 

phenomenon known as steady-state AChE inhibition. After repeated dosing at the same dose level, 

the degree of inhibition comes into equilibrium with the production of new, uninhibited enzyme. 

Therefore, 2-day average assessments were conducted instead of traditional chronic assessments.

The DEEM acute model is typically used to conduct 2-day average assessments for the OPs using the 

steady-state PoD, 2-day food consumptions, and 21-day forward-rolling water averages. These 2-day 

average assessments provide an estimate of 21-day (“steady-state”) average daily food and drinking 

water exposures. For terbufos, a screening level high-end point estimate was used for the drinking 

water concentrations as opposed to a distribution of the 21-day forward-rolling averages. For food, 

the 2-day average assessments reflect an average daily exposure for a 2-day exposure duration rather 

than a 21-day exposure duration. Since the DEEM 2-day average assessment does not capture dayto-day variation in food residues, it will generally result in higher food-only exposure estimates than a 

model that calculates 21-day rolling averages for food. Although the DEEM 2-day average 

assessment for terbufos may result in higher exposure estimates for both drinking water and food, the 

assessment provides an acceptable estimate of 21-day (“steady-state”) average daily exposure for 

food and drinking water for use in risk assessment. 

The most recent dietary exposure analysis of terbufos was conducted in support of the interim 

registration eligibility decision (IRED) issued in 1999 (D258668, C. Swartz, 08/26/1999).

II. Residue Information

Terbufos (S-[[(1,1-Dimethylethyl)thio]0,0-diethyl phosphorodithioate) is an organophosphate 

insecticide used in agriculture to control pests which affect bananas, coffee, corn, sugar beets, and 

sorghum. Existing and reassessed tolerances are established for the combined residues of terbufos 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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and its cholinesterase-inhibiting metabolites in or on plant commodities under 40 CFR §180.352. 

The cholinesterase-inhibiting metabolites of terbufos include terbufos oxygen analog (oxon), terbufos 

sulfoxide, terbufos sulfone, terbufos oxygen analog sulfoxide, and terbufos oxygen analog sulfone. 

Adequate data collection and enforcement methods are available to detect terbufos residues in plant 

commodities. Tolerances are not required for residues in livestock commodities since there is no 

reasonable expectation of detectable residues, 40 CFR §180.6(a)3.

Residues of Concern in Plants and Drinking Water: The terbufos residues of concern for plants and 

drinking water are shown below in Table 1. 

Table 1. Summary of Terbufos Residues of Concern.

Matrix Residues included in Risk 

Assessment

Residues included in 

Tolerance Expression

Plants

Terbufos (parent), Terbufos 

Oxygen Analog (Oxon), 

Terbufos Sulfoxide, 

Terbufos Sulfone, Terbufos 

Oxygen Analog Sulfoxide, 

and Terbufos Oxygen 

Analog Sulfone. 

Terbufos (parent), Terbufos 

Oxygen Analog (Oxon), 

Terbufos Sulfoxide, 

Terbufos Sulfone, Terbufos 

Oxygen Analog Sulfoxide, 

and Terbufos Oxygen 

Analog Sulfone. 

Drinking Water

Terbufos (parent), Terbufos 

Sulfoxide, and Terbufos 

Sulfone.1

Not applicable

1 Upon submission of additional information, the ROCKS Committee revisited the residues of concern in drinking water 

and determined the residues of concern to be parent, terbufos sulfoxide, and terbufos sulfone since the oxon degradates 

are not being detected in surface or ground water (D417464, E. Scollon, 02/03/14).

Residues used in Acute and Steady-State (Acute 2-Day Average) Dietary Analyses: Unrefined acute 

and steady-state (acute 2-day average) dietary exposure assessments were conducted with 100% crop 

treated data which used residue inputs from field trial results. USDA PDP data were not used for 

dietary assessment because all of the metabolites of concern were not analyzed. No new residue data 

have been generated for this assessment and there are no changes in the residue inputs from the 

existing field trial data. Therefore, residue inputs from the previous dietary analyses have been used 

in this assessment. These data are summarized below in Table 2 with the residue distribution files 

(RDFs) used in the current acute analysis shown in detail in Appendix 1. 

Table 2. Data Sources and Residue Estimates for Terbufos Dietary Analysis.

Commodity DEEM 

Food Form 

(Classificat

ion)

Data Source

(MRID No.)

# of Samples/#of 

Detects

1⁄2 LOQ 

(ppm)

Processing 

Factor

% Crop 

Treated

Anticipated 

Residue

(ppm)

(Tol., AR, or 

RDF)

Bananas NB/PB Field Trials/

44629302

00158608

00158610

00158612

00158613

“13”samples/”1” 

detects

NA1 NA 100 RDF #1

Totalz=0

Totalnz=13
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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Table 2. Data Sources and Residue Estimates for Terbufos Dietary Analysis.

Commodity DEEM 

Food Form 

(Classificat

ion)

Data Source

(MRID No.)

# of Samples/#of 

Detects

1⁄2 LOQ 

(ppm)

Processing 

Factor

% Crop 

Treated

Anticipated 

Residue

(ppm)

(Tol., AR, or 

RDF)

Bananas, dried B Field Trials/

44629302

00158608

00158610

00158612

00158613

“13”samples/”1” 

detects

NA 3.9

(default 

value)

100 0.0043 avg.

(blended 

commodity; 

avg. of 13 

field trials)

Field Corn B Field Trials/

44629303

“10” samples/”0” 

detects

0.005 1 100 0.005 

Sweet Corn NB/PB Field Trials/

43237802

“10” samples/”0” 

detects

0.005 1 100 RDF #2

Totalz= 0

Totalnz=10

Sugar Beets B Field Trials/

00036127

“11” samples/”0” 

detects

0.025 1 100 0.025

Sorghum, grain B Field Trials/

00079431

Not Noted/”0” 

detects

0.025 NA 100 0.025

Coffee B 40365901 “8” samples/”1” 

detect

NA 1 100 0.028

(blended 

commodity; 

avg. of 8 

field trials)

1 NA – Not Applicable

Anticipated residues (ARs) were previously calculated for a prior dietary assessment made for 

terbufos (D244268, W. J. Hazel, 03/19/1998). 

Banana

Using these data, banana pulp results totaling 13 data points were used to create a residue data file 

(RDF) for assessment which includes plantains since cultural practices are similar for both 

commodities. This data set did include one positive detected result of 0.015 ppm. Dried banana is a 

blended commodity and the average of the 13 field trial results are used for this residue input. 

Corn

The residue values used for field corn and popcorn are based on non-detectable residues and a half 

LOQ value is used for the assessment of these blended commodities. Because these data were 

acquired as exaggerated rate field trials, there is no expectation of residues in any byproducts and the 

corn processing study was thus waived. For sweet corn, 10 data points acquired from prior field trial 

studies were used to create an RDF for assessment. 

Sugar beet

The prior field trials made for sugar beet showed no detectable residues of terbufos which results in a 

half LOQ value of 0.025 ppm to be used for assessment. In regard to sugar beet byproducts, no 

residues were detected in the processing study made on thick juice as noted in the 1983 registration 

standard. As a result, there is no expectation of residues in sugar beet molasses and syrup. 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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Sorghum

The prior field trials made for sorghum grain showed no detectable residues of terbufos which results 

in a half LOQ value of 0.025 ppm to be used for assessment. Since no detectable residues are found 

in sorghum grain, there is no reasonable expectation that detectable residues will be found in any 

byproducts (Terbufos Registration Standard, C. Trichilo, 01/19/1983). 

Coffee

For coffee, the average of 8 field trial results were used as the residue input of this blended 

commodity for assessment. 

Fish: The USDA PDP monitored pesticides data in catfish between 2008 through 2010. PDP 

analyzed 1479 samples of catfish for terbufos residues. None of these samples contained detectable 

residues and fish is not included in the assessment.

III. Percent Crop Treated Information

The acute and steady-state (acute 2-day average) aggregate dietary analyses were performed 

assuming 100% of each commodity was treated with terbufos. The use of percent crop treated data 

would not further refine these dietary analyses since the majority of the field trial data are non-detect

results. Irrespective, the Biological and Economic Analysis Division (BEAD) has recommended that 

100% crop treated data be used for the representation of banana and coffee residues (D419906, J. 

Alsadek, 06/11/2014). 

IV. Drinking Water Data

The drinking water residues determined for terbufos used for dietary risk assessment were provided 

by the Environmental Fate and Effects Division (EFED). The EFED determination uses maximum 

application rates but also considers typical application rates and reduction through bounding from 

vegetative buffers for the additional characterization of dietary risk. It provides estimated drinking 

water concentrations (EDWCs) for terbufos and its two major oxidative degradates, terbufos 

sulfoxide and terbufos sulfone in both surface water and groundwater. It considers a parent only 

approach but also considers the oxidative degradates of terbufos as parent in a total toxic residue 

(TTR) approach. Inclusion of the TTR approach is provided for a complete characterization of 

EDWCs. Some OPs require metabolic activation to the oxon metabolite. However, terbufos is not 

one of these OPs and is already in the oxon form.

Registered use sites include corn at the maximum application rate of 1.3 lbs. a.i./A, sorghum at 1.68 

lbs. a.i./A, and sugar beet at 1.98 lbs. a.i./A. Modeling for these ground application scenarios of 

terbufos used the coupled models PRZM and EXAMS for surface water and SCI-GROW as well as 

PRZM-GW for groundwater. The highest EDWCs for the TTR of terbufos result from the Texas 

sorghum OP scenario (D418656, F. Khan, 04/08/2014). For the characterization of dietary risk, an 

amended time-series of TTR using a typical application rate for sorghum was also provided by EFED 

(D423572, F. Khan, 10/29/2014). In this amended assessment, the reported time-series values were 

adjusted based on a typical use rate of 0.895 lbs a.i./A for sorghum, which is 53 percent of the 

maximum rate of 1.68 lbs a.i./A. Since there is a linear relationship between the application rate and 

modeled EDWCs, previously reported time-series values for the Texas sorghum scenario were 

adjusted simply by multiplying with 0.53 to represent the typical rate for sorghum. An additional 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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characterization scenario also considered by EFED for use in dietary assessment was an assumed 

90% reduction in the EDWCs determined for terbufos through the bounding of residues in vegetative 

buffers (D428089, F. Khan, 07/10/2015). No additional modeling was considered since all of the 

input parameters from previous modeling using the maximum use rates remain unchanged. 

Recommended EDWCs for terbufos and TTRs of terbufos in surface water and ground are 

summarized below in Table 3. Daily time series outputs for the thirty year simulation were provided 

to HED for use in dietary exposure modeling. 

Table 3. Recommended EDWCs for Drinking Water Risk Assessment for Terbufos and its Degrates.

Source of Drinking Water Estimated Drinking Water Concentration (μg/L)

1-in-10-year Peak 

Exposure

1-in-10-year Annual Mean 

Exposure

30-year Mean Exposure

Total Toxic Residues of Terbufos (Terbufos plus Terbufos Sulfoxide and terbufos Sulfone)

Surface Water (Max Rate 

for sorghum)1, 2

63.06 11.53 6.13

Surface Water (Typical 

Rate for sorghum)1, 2, 3

33.42 6.11 3.25

Groundwater4 33.54 -- 14.02

Terbufos (Parent only)

Surface Water2, 5 46.02 0.28 0.12

Groundwater6 0.02 0.02 0.02

1 EDWCs based on PRZM/EXAMS model and residue summation method for TX sorghum OP scenario.

2 PCA adjusted modeled values.

3 0.53 adjustment factor used in calculating EDWCs.

4 Highest EDWCs based summation of terbufos, terbufos sulfoxide, and terbufos sulfone derived from PRZM-GW 

model for Delmarva scenario.

5 EDWCs based on PRZM/EXAMS model for parent terbufos alone for MS corn STD scenario.

6 EDWCs for parent terbufos were derived from SCI-GROW model.

 

V. DEEM-FCIDTM Program and Consumption Information

The terbufos acute and steady-state (acute 2-day average) dietary exposure and risk assessments were

conducted using the DEEM-FCIDTM, Version 3.16. This software uses 2003-2008 food consumption 

data from the U.S. Department of Agriculture’s (USDA’s) National Health and Nutrition 

Examination Survey, What We Eat in America, (NHANES/WWEIA). These data are based on the 

reported consumption of more than 20,000 individuals over two non-consecutive survey days. Foods 

“as consumed” (e.g., apple pie) are linked to EPA-defined food commodities (e.g. apples, peeled fruit 

- cooked; fresh or N/S; baked; or wheat flour - cooked; fresh or N/S, baked) using publicly available 

recipe translation files developed jointly by USDA/ARS and EPA. For chronic exposure assessment, 

consumption data are averaged for the entire U.S. population and within population subgroups, but 

for acute exposure assessment are retained as individual consumption events. Based on analysis of 

the 2003-2008 WWEIA consumption data, which took into account dietary patterns and survey 

respondents, HED concluded that it is most appropriate to report risk for the following population 

subgroups: the general U.S. population, all infants (<1 year old), children 1-2, children 3-5, children 

6-12, youth 13-19, adults 20-49, females 13-49, and adults 50-99 years old.

For an acute exposure assessment, individual one-day food consumption data are used on an 

individual-by-individual basis. The reported consumption amounts of each food item can be 

multiplied by a residue point estimate and summed to obtain a total daily pesticide exposure for a 

deterministic exposure assessment, or “matched” in multiple random pairings with residue values and 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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thgen summed in a probabilistic assessment. The resulting distribution of exposures is expressed as a 

percentage of the aPAD on both a user (i.e.; only those who reported eating relevant 

commodities/food forms) and a per-capita (i.e.; those who reported eating the relevant commodities 

as well as those who did not) basis. In accordance with HED policy, per-capita exposure and risk are 

reported for analyses performed at all levels of refinement. However, for deterministic assessments, 

any significant differences in user vs. per-capita exposure and risk are specifically identified and 

noted in the risk assessment. 

For the steady-state (acute 2-day average) exposure assessment, 2-day average food consumptions are 

calculated on an individual-by-individual basis. The reported consumption amounts of each food 

item for each day are added together and then divided by two (2) days. For example, if an individual 

reports eating 100 grams of apple on the first day and 0 grams of apple on the second day, the 2-day 

average consumption amount would be 50 grams/day of apple [(100 grams + 0 grams)/2-days = 50 

grams/day]. The resulting 2-day average consumption amount can then be multiplied by a residue 

point estimate and summed to obtain a total daily pesticide exposure for a deterministic exposure 

assessment, or “matched” in multiple random pairings with residue values and then summed in a 

probabilistic assessment. The resulting distribution of exposures is expressed as a percentage of the 

PAD on both a user (i.e., only those who reported eating relevant commodities/food forms) and percapita (i.e., those who reported eating the relevant commodities as well as those who did not) basis. 

In accordance with HED policy, per capita exposure and risk are reported for analyses performed at 

all levels of refinement. However, for deterministic assessments, any significant differences in user 

vs. per capita exposure and risk are specifically identified and noted in the risk assessment. 

VI. Toxicological Information

Terbufos is a member of the OP class of pesticides. Like other OPs, the initiating event in the 

adverse outcome pathway (AOP), also often called the mode of action (MOA), for terbufos involves 

inhibition of the enzyme acetylcholinesterase (AChE) via phosphorylation of the serine residue at the 

active site of the enzyme. This inhibition leads to accumulation of acetylcholine and ultimately to 

neurotoxicity in the central and/or peripheral nervous system. For terbufos, AChE inhibition is the 

most sensitive endpoint in the toxicology database in multiple species, durations, lifestages, and 

routes. After repeated dosing at the same dose, the degree of inhibition comes into equilibrium with 

the production of new, uninhibited enzyme. At this point the amount of AChE inhibition at a given 

dose remains consistent across duration.

The RABV/VII toxicologists have re-evaluated the terbufos database and updated the endpoints as 

necessary. In the case of terbufos, many of the data sets were not amenable to benchmark dose 

(BMD) modeling. For the BMD analyses that were made, there is no pattern of increasing toxicity 

apparent with time; the BMD values vary within a narrow range. In general, following terbufos 

exposure, RBC and brain ChE inhibition are similarly/equally sensitive. In addition to the 

consistency across durations, the data across multiple studies (repeat CCA study, gestational data 

from the DNT, subchronic neurotoxicity study) are similar. These data are concluded to be consistent 

with the OP cumulative risk assessment, which included subchronic and chronic data for 

terbufos. Given the results for terbufos, acute (single day) and steady state durations are appropriate 

for human health risk assessment. HED’s ToxSAC met (04/03/2014) to consider the endpoints of 

toxicological concern for dietary exposure. 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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An uncertainty factor of 100X (10X to account for interspecies extrapolation and 10X for intraspecies 

variation) is applied to the BMDL10 to obtain the resulting endpoint. The 10X for FQPA SF due to 

uncertainty in the human dose-response relationship for neurodevelopmental effects will be retained 

for the population subgroups that include infants, children, youths, and women of child-bearing age 

for all exposure scenarios. A summary of the endpoint selection is presented below in Table 4 which 

focuses on presenting the acute, single day effects and steady state effects. For purposes of 

consistency with the OP cumulative risk assessment (CRA) and other OPs, exposure assessments of 

21 days and longer will be conducted.

 Table 4. Summary of Toxicological Doses and Endpoints for Terbufos for Use in Dietary Exposure Risk 

Assessment.

Exposure/

Scenario

Point of 

Departure

Uncertainty/FQP

A Safety Factors

RfD, PAD, Level 

of Concern Study and Toxicological Effects

Acute Dietary (All 

Populations except 

adults 50-99 years old)

BMDL10 = 

0.02

mg/kg/day

UF = 100x

FQPA SF = 10x

aRfD = aPAD = 

0.00002 mg/kg/day

CCA Study (MRID No. 46247601) 

in the rat – RBC inhibition in PND 

11 males.

Acute Dietary (adults 

50-99 years old)

BMDL10 = 

0.02 

mg/kg/day

UF = 100x

FQPA SF = 1x

aRfD = aPAD = 

0.0002 mg/kg/day

CCA Study (MRID No. 46247601) 

in the rat – RBC inhibition in PND 

11 males.

Steady-State Dietary 

(All Populations

except adults 50-99 

years old)

BMDL10 = 

0.01 

mg/kg/day

UF = 100x

FQPA SF = 10X

ssRfD = ssPAD = 

0.00001 mg/kg/day

Neurotoxicity Studies (MRID Nos. 

46240802 & 46214301) in the rat -

RBC ChE inhibition in female 

PND 21 pups & GD 20 male 

fetuses, and brain cholinesterase 

inhibition in PND 21 males & GD 

20 dams.

Steady-State Dietary 

(adults 50-99 years 

old)

BMDL10 = 

0.01 

mg/kg/day

UF = 100x

FQPA SF = 1X

ssRfD = ssPAD = 

0.0001 mg/kg/day

Neurotoxicity Studies (MRID Nos. 

46240802 & 46214301) in the rat -

RBC ChE inhibition in female 

PND 21 pups & GD 20 male 

fetuses, and brain cholinesterase 

inhibition in PND 21 males & GD 

20 dams.

Cancer (oral, dermal, 

inhalation) Classification: “Not Likely to be Carcinogenic to Humans”

Point of Departure (PoD) = A data point or an estimated point that is derived from observed dose-response data and used 

to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human 

exposures. BMDL10 = benchmark dose lower limit 10% response. UF = uncertainty factor. FQPA SF = FQPA Safety 

Factor. PAD = population adjusted dose (a = acute, and ss = steady-state). RfD = reference dose. 

VII. Results/Discussion 

As stated above, for acute and steady-state assessments, HED is concerned when dietary risk exceeds 

100% of the PAD. The DEEM-FCID (ver. 3.16) analyses estimate the dietary exposure of the U.S. 

population and all its various population subgroups. The results reported in Tables 5 and 6 are for 

estimating the dietary exposure of the U.S. population and all its various population subgroups. The 

results reported below are for the general U.S. Population, all infants (<1 year old), children 1-2, 

children 3-5, children 6-12, youth 13-19, females 13-49, adults 20-49, and adults 50-99 years. 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

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Results of Acute Dietary (Food plus Drinking Water) Exposure Analysis

For food plus drinking water, the acute dietary risk estimate exceeded HED’s level of concern at the 

95th percentile of exposure. The acute dietary exposure was estimated for the U.S. population to be 

1900% of the aPAD with an exposure of 0.000389 mg/kg/day at the 95th percentile. The most highly 

exposed population subgroup is all infants (<1 year old) having an estimate of 5300% of the aPAD

with an exposure of 0.001055 mg/kg/day at the 95th percentile. 

 Table 5. Results of Acute Dietary Exposure Analysis for Terbufos (Food and Drinking 

Water-Max Rate).

Population Subgroup aPAD

(mg/kg/day)

95th Percentile

Exposure (mg/kg/day) % aPAD

General U.S. Population 0.00002 0.000389 1900

All Infants (<1 year old) 0.00002 0.001055 5300

Children 1-2 years old 0.00002 0.000587 2900

Children 3-5 years old 0.00002 0.000502 2500

Children 6-12 years old 0.00002 0.000359 1800

Youth 13-19 years old 0.00002 0.000289 1400

Adults 20-49 years old 0.00002 0.000388 1900

Adults 50-99 years old 0.0002 0.000378 190

Females 13-49 years old 0.00002 0.000387 1900

1 Acute dietary analysis derived from a 0.00002 mg/kg/day aPAD for the general population except for adults 50-99 years 

old which use a 0.0002 mg/kg/day aPAD. 

2 Highest exposures found for assessment is noted in bold.

Results of Steady-State Acute 2-Day Average Dietary (Food plus Drinking Water) Exposure Analysis

The steady-state aggregate dietary (food plus drinking water) exposure estimates are above HED’s 

level of concern for the U.S. population and all populations subgroups. Combined dietary exposure 

for the U.S. population from food and drinking water is 3800% of the ssPAD with an exposure of 

0.000380 mg/kg/day at the 95th percentile. The most highly exposed population subgroup is all 

infants (<1 year old) having an estimate of >10000% of the ssPAD with an exposure of 0.001038

mg/kg/day at the 95th percentile.

 Table 6. Results of Steady-State Dietary Exposure Analysis for Terbufos (Food and Drinking 

Water-TX Sorghum Maximum Rate) using the Acute 2-Day Avereage Analysis.

Population Subgroup aPAD

(mg/kg/day)

95th Percentile

Exposure (mg/kg/day) % aPAD

General U.S. Population 0.00001 0.000380 3800

All Infants (<1 year old) 0.00001 0.001038 >10000

Children 1-2 years old 0.00001 0.000574 5700

Children 3-5 years old 0.00001 0.000486 4900

Children 6-12 years old 0.00001 0.000350 3500

Youth 13-19 years old 0.00001 0.000284 2800

Adults 20-49 years old 0.00001 0.000377 3800

Adults 50-99 years old 0.0001 0.000368 370

Females 13-49 years old 0.00001 0.000378 3800

1 Acute 2-day dietary analysis derived from a 0.00001 mg/kg/day ssPAD for the general population except for adults 50-

99 years old which use a 0.0001 mg/kg/day ssPAD.

2 Highest exposures found for assessment is noted in bold.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 11 of 44

VIII.Characterization of Inputs/Outputs

HED has conducted unrefined acute and steady-state dietary risk assessments for terbufos using 

100% crop treated data with residue inputs from field trial results. USDA PDP data were not used for 

dietary assessment because all of the metabolites of concern were not analyzed. The use of percent 

crop treated data were not used to further refine these dietary analyses since the majority of the field 

trial data are non-detect results. Although averaging the 2 consumption days for each individual 

consumer in the DEEM consumption database e assessments may result in higher exposure estimates 

for food than in a typical chronic DEEM analysis, this provides a high-end estimate of 21-day 

(“steady-state”) exposure for food and drinking water. Exposures were above HED’s level of 

concern for the U.S population and all population subgroups. The critical exposure contribution 

(CEC) analysis performed for all infants <1 year of age (the population subgroup with the highest 

dietary exposure) shows that drinking water is the driver of dietary risk (Attachment 10). The CEC 

analyses for all infants < 1 year of age also shows that the greatest contribution to dietary risk from 

food, although minor in comparison to that of drinking water, is from bananas. 

Characterization of Acute Dietary Risk Assessed with Maximum Rate EDWCs

The highest EDWCs for the TTR of terbufos result from the Texas sorghum scenario using the 

highest maximum application rate. These analyses presented in Table 7 show acute dietary exposure 

estimates for food only, water only, as well as for food and drinking water are all above HED’s level 

of concern for the U.S. population and all its population subgroups at the 95th percentile. For the U.S. 

population, the combined dietary exposure from food plus drinking water is 1900% of the aPAD with 

an exposure of 0.000389 mg/kg/day at the 95th percentile. All infants <1 year old was the population 

subgroup with the highest combined exposure from food plus drinking water at 5300% of the aPAD 

with an exposure of 0.001055 mg/kg/day at the 95th percentile.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 12 of 44

Table 7. Results of Acute Dietary Exposure Analysis for Terbufos Food only and Drinking Water only, 

and Food plus Drinking Water using Maximum Rate EDWCs.

Population 

Subgroup

aPAD

(mg/kg/day)

Food only Drinking Water only 

(Maximum Rate)

Food plus Drinking 

Water (Maximum Rate)

95th Percentile 95th Percentile 95th Percentile

Exposure 

(mg/kg/day)

% aPAD Exposure 

(mg/kg/day)

% aPAD Exposure 

(mg/kg/day)

% aPAD

General U.S. 

Population

0.00002 0.000056 280 0.000366 1800 0.000389 1900

All Infants (<1 

year old)

0.00002 0.000122 610 0.001020 5100 0.001055 5300

Children 1-2 

years old

0.00002 0.000126 630 0.000527 2600 0.000587 2900

Children 3-5 

years old

0.00002 0.000109 540 0.000450 2200 0.000502 2500

Children 6-12 

years old

0.00002 0.000079 390 0.000323 1600 0.000359 1800

Youth 13-19 

years old

0.00002 0.000049 240 0.000269 1300 0.000289 1400

Adults 20-49 

years old

0.00002 0.000042 210 0.000370 1800 0.000388 1900

Adults 50-99 

years old

0.0002 0.000035 18 0.000362 180 0.000378 190

Females 13-49 

years old

0.00002 0.000040 200 0.000370 1800 0.000387 1900

1 Acute dietary analysis derived from a 0.00002 mg/kg/day aPAD for the general population except for adults 50-99 years 

old which use a 0.0002 mg/kg/day aPAD.

2 Highest exposures found for assessment is noted in bold.

Characterization of Acute Dietary Risk Assessed with Typical Rate EDWCs

To further depict dietary exposure, typical application rates were also considered to provide for a 

complete characterization of the EDWCs. For the Texas sorghum scenario modeled for terbufos, a 

0.53 reduction factor is realized in determining these EDWCs. The acute dietary results at the 95th

percentile for the analysis of food only, drinking water only, and food plus drinking water determined 

using typical rate EDWCs are presented in Table 8. Although lower results are obtained, all acute 

analyses still exceed HED’s level of concern at the 95th percentile of exposure (except for adults 50-

99 years old for food only). These analyses show that for the U.S. population the combined dietary 

exposure from food plus drinking water is 1100% of the aPAD with an exposure of 0.000220 

mg/kg/day at the 95th percentile. All infants <1 year old was the population subgroup with the 

highest combined exposure from food plus drinking water at 2900% of the aPAD with an exposure of 

0.000580 mg/kg/day at the 95th percentile.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 13 of 44

 Table 8. Results of Acute Dietary Exposure Analysis for Terbufos Food only, Drinking Water only, and 

Food plus Drinking Water using Typical Rate EDWCs.

Population 

Subgroup

aPAD

(mg/kg/day)

Food only Drinking Water only 

(Typical Rate)

Food plus Drinking 

Water (Typical Rate)

95th Percentile 95th Percentile 95th Percentile

Exposure 

(mg/kg/day)

% 

aPAD

Exposure 

(mg/kg/day)

% aPAD Exposure 

(mg/kg/day)

% aPAD

General U.S. 

Population

0.00002 0.000056 280 0.000195 980 0.000220 1100

All Infants (<1 

year old)

0.00002 0.000122 610 0.000543 2700 0.000580 2900

Children 1-2 

years old

0.00002 0.000126 630 0.000281 1400 0.000347 1700

Children 3-5 

years old

0.00002 0.000109 540 0.000239 1200 0.000294 1500

Children 6-12 

years old

0.00002 0.000079 390 0.000171 860 0.000212 1100

Youth 13-19 

years old

0.00002 0.000049 240 0.000143 720 0.000165 820

Adults 20-49 

years old

0.00002 0.000042 210 0.000197 980 0.000215 1100

Adults 50-99 

years old

0.0002 0.000035 18 0.000193 96 0.000209 100

Females 13-49 

years old

0.00002 0.000040 200 0.000197 980 0.000214 1100

1 Acute dietary analysis derived from a 0.00002 mg/kg/day aPAD for the general population except for adults 50-99 years 

old which use a 0.0002 mg/kg/day aPAD.

2 Highest exposures found for assessment is noted in bold.

Characterization of Acute Dietary Risk Assessed with a Vegetative Buffer Reduction of EDWCs

An additional characterization scenario was also considered by EFED for use in dietary assessment 

which assumes a 90% reduction in the EDWCs through the use of vegetative buffers. The acute 

dietary results at the 95th percentile for the analysis of food only, drinking water only, and food plus

drinking water determined using 90% reduced EDWCs are presented in Table 9. Although much 

lower, all acute analyses still exceed HED’s level of concern at the 95th percentile of exposure (except 

for adults 50-99 years old). These analyses show that for the U.S. population the combined dietary 

exposure from food plus drinking water is 400% of the aPAD with an exposure of 0.000079 

mg/kg/day at the 95th percentile. All infants <1 year old was the population subgroup with the 

highest combined exposure from food plus drinking water at 870% of the aPAD with an exposure of 

0.000175 mg/kg/day at the 95th percentile.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 14 of 44

 Table 9. Results of Acute Dietary Exposure Analysis for Terbufos Food only, Drinking Water only, and 

Food plus Drinking Water using 90% Reduced EDWCs for a Vegetative Buffer.

Population 

Subgroup

aPAD

(mg/kg/day)

Food only Drinking Water only 

(90% Reduced EDWCs 

for a Vegetative Buffer)

Food plus Drinking 

Water (90% Reduced 

EDWCs for a Vegetative 

Buffer)

95th Percentile 95th Percentile 95th Percentile

Exposure 

(mg/kg/day)

% aPAD Exposure 

(mg/kg/day)

% aPAD Exposure 

(mg/kg/day)

% aPAD

General U.S. 

Population

0.00002 0.000056 280 0.000037 180 0.000079 400

All Infants (<1 

year old)

0.00002 0.000122 610 0.000102 510 0.000175 870

Children 1-2 

years old

0.00002 0.000126 630 0.000053 260 0.000157 790

Children 3-5 

years old

0.00002 0.000109 540 0.000045 220 0.000133 660

Children 6-12 

years old

0.00002 0.000079 390 0.000032 160 0.000095 480

Youth 13-19 

years old

0.00002 0.000049 240 0.000027 130 0.000064 320

Adults 20-49 

years old

0.00002 0.000042 210 0.000037 180 0.000064 320

Adults 50-99 

years old

0.0002 0.000035 18 0.000036 18 0.000059 29

Females 13-49 

years old

0.00002 0.000040 200 0.000037 180 0.000063 310

1 Acute dietary analysis derived from a 0.00002 mg/kg/day aPAD for the general population except for adults 50-99 years 

old which use a 0.0002 mg/kg/day aPAD.

2 Highest exposures found for assessment is noted in bold.

Characterization of Steady-State Dietary Risk Assessed with Maximum Rate EDWCs

For the steady-state dietary analyses determined using maximum application rate derived EDWCs, 

the results of food only, drinking water only, and food plus drinking water at the 95th percentile are 

presented in Table 10. Risks are all above HED’s level of concern for the U.S. population and all its 

population subgroups at the 95th percentile (except for adults 50-99 years old for food only). For the 

U.S. population the combined dietary exposure from food plus drinking water is 3800% of the ssPAD 

with an exposure of 0.000380 mg/kg/day at the 95th percentile. All infants <1 yr old was the 

population subgroup with the highest combined exposure from food plus drinking water at >10000% 

of the ssPAD with an exposure of 0.001038 mg/kg/day at the 95th percentile.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 15 of 44

 Table 10. Results of Steady-State Dietary Exposure Analysis for Terbufos Food only, Drinking Water 

only, and Food plus Drinking Water-using Maximum Rate EDWCs.

Population 

Subgroup

ssPAD

(mg/kg/day)

Food only Drinking Water only 

(Maximum Rate)

Food plus Drinking 

Water (Maximum Rate)

95th Percentile 95th Percentile 95th Percentile

Exposure 

(mg/kg/day)

% ssPAD Exposure 

(mg/kg/day)

% ssPAD Exposure 

(mg/kg/day)

% ssPAD

General U.S. 

Population

0.00001 0.000053 530 0.000357 3600 0.000380 3800

All Infants (<1 

year old)

0.00001 0.000111 1100 0.000999 10000 0.001038 >10000

Children 1-2 

years old

0.00001 0.000113 1100 0.000517 5200 0.000574 5700

Children 3-5 

years old

0.00001 0.000097 970 0.000436 4400 0.000486 4900

Children 6-12 

years old

0.00001 0.000072 720 0.000314 3100 0.000350 3500

Youth 13-19 

years old

0.00001 0.000044 440 0.000263 2600 0.000284 2800

Adults 20-49 

years old

0.00001 0.000039 390 0.000360 3600 0.000377 3800

Adults 50-99 

years old

0.0001 0.000032 32 0.000351 350 0.000368 370

Females 13-49 

years old

0.00001 0.000037 370 0.000360 3600 0.000378 3800

1 Steady-State dietary analysis derived from a 0.00001 mg/kg/day ssPAD for the general population except for adults 50-

99 years old which use a 0.0001 mg/kg/day ssPAD.

2 Highest exposures found for assessment is noted in bold.

Characterization of Steady-State Dietary Risk Assessed with Typical Rate EDWCs

In order to provide a complete characterization of the steady-state dietary exposure of terbufos, 

EDWCs derived using typical application rates are also considered for assessment. In accordance, 

the steady-state dietary results for the analysis of food only, drinking water only, food plus drinking

water at the 95th percentile determined with typical rate EDWCs are presented in Table 11. Although 

lower results are obtained, steady-state dietary exposure estimates for food only, water only, as well 

as for food plus drinking water are also all above HED’s level of concern for the U.S. population and 

all its population subgroups at the 95th percentile (except for adults 50-99 years old for food only). 

These analyses show that for the U.S. population the combined dietary exposure from food plus

drinking water is 2100% of the ssPAD with an exposure of 0.000213 mg/kg/day at the 95th percentile. 

All infants <1 yr old was the population subgroup with the highest combined exposure from food plus

drinking water at 5700% of the ssPAD with an exposure of 0.000569 mg/kg/day at the 95th percentile.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 16 of 44

 Table 11. Results of Steady-State Dietary Exposure Analysis for Terbufos Food only, Drinking Water 

only, and Food plus Drinking Water-using Typical Rate EDWCs.

Population 

Subgroup

ssPAD

(mg/kg/day)

Food only Drinking Water only 

(Typical Rate)

Food plus Drinking 

Water (Typical Rate)

95th Percentile 95th Percentile 95th Percentile

Exposure 

(mg/kg/day)

% ssPAD Exposure 

(mg/kg/day)

% ssPAD Exposure 

(mg/kg/day)

% ssPAD

General U.S. 

Population

0.00001 0.000053 530 0.000189 1900 0.000213 2100

All Infants (<1 

year old)

0.00001 0.000111 1100 0.000529 5300 0.000569 5700

Children 1-2 

years old

0.00001 0.000113 1100 0.000274 2700 0.000335 3300

Children 3-5 

years old

0.00001 0.000097 970 0.000231 2300 0.000284 2900

Children 6-12 

years old

0.00001 0.000072 720 0.000166 1700 0.000205 2000

Youth 13-19 

years old

0.00001 0.000044 440 0.000139 1400 0.000161 1600

Adults 20-49 

years old

0.00001 0.000039 390 0.000191 1900 0.000209 2100

Adults 50-99 

years old

0.0001 0.000032 32 0.000186 190 0.000203 200

Females 13-49 

years old

0.00001 0.000037 370 0.000190 1900 0.000208 2100

1 Steady-State dietary analysis derived from a 0.00001 mg/kg/day ssPAD for the general population except for adults 50-

99 years old which use a 0.0001 mg/kg/day ssPAD.

2 Highest exposures found for assessment is noted in bold.

Characterization of Steady-State Dietary Risk Assessed with a Vegetative Buffer Reduction of 

EDWCs

Steady-state dietary analyses were also performed to consider the additional characterization scenario 

developed by EFED which assumes a 90% reduction in the EDWCs through the use of vegetative 

buffers. The steady-state dietary results at the 95th percentile for the analysis of food only, drinking 

water only, and food plus drinking water determined using 90% reduced EDWCs are presented in 

Table 12. Although much lower, all steady-state analyses still exceed HED’s level of concern at the 

95th percentile of exposure (except for adults 50-99 years old). These analyses show that for the U.S. 

population the combined dietary exposure from food plus drinking water is 750% of the ssPAD with 

an exposure of 0.000075 mg/kg/day at the 95th percentile. All infants <1 year old was the population 

subgroup with the highest combined exposure from food plus drinking water at 1600% of the ssPAD 

with an exposure of 0.000164 mg/kg/day at the 95th percentile.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 17 of 44

 Table 12. Results of Steady-State Dietary Exposure Analysis for Terbufos Food only, Drinking Water 

only, and Food plus Drinking Water using 90% Reduced EDWCs for a Vegetative Buffer.

Population 

Subgroup

ssPAD

(mg/kg/day)

Food only Drinking Water only 

(90% Reduced EDWCs 

for a Vegetative Buffer)

Food plus Drinking 

Water (90% Reduced 

EDWCs for a Vegetative 

Buffer)

95th Percentile 95th Percentile 95th Percentile

Exposure 

(mg/kg/day)

% aPAD Exposure 

(mg/kg/day)

% aPAD Exposure 

(mg/kg/day)

% aPAD

General U.S. 

Population

0.00001 0.000053 530 0.000036 360 0.000075 750

All Infants (<1 

year old)

0.00001 0.000111 1100 0.000100 1000 0.000164 1600

Children 1-2 

years old

0.00001 0.000113 1100 0.000052 520 0.000144 1400

Children 3-5 

years old

0.00001 0.000097 970 0.000044 440 0.000119 1200

Children 6-12 

years old

0.00001 0.000072 720 0.000031 310 0.000089 890

Youth 13-19 

years old

0.00001 0.000044 440 0.000026 260 0.000058 580

Adults 20-49 

years old

0.00001 0.000039 390 0.000036 360 0.000061 600

Adults 50-99 

years old

0.0001 0.000032 32 0.000035 35 0.000056 56

Females 13-49 

years old

0.00001 0.000037 370 0.000036 360 0.000059 590

1 Steady-State dietary analysis derived from a 0.00001 mg/kg/day ssPAD for the general population except for adults 50-

99 years old which use a 0.0001 mg/kg/day ssPAD.

2 Highest exposures found for assessment is noted in bold.

Drinking Water Level of Comparison (DWLOC)

The acute CEC analysis made for all infants <1 year of age shows that drinking water is the driver of 

dietary risk from terbufos. As a further characterization of dietary exposure, a drinking water level of 

comparison (DWLOC) was determined for the general U.S. population and the sentinel population 

subgroups of all infants < 1 year old and females 13- 49 years old. The DWLOC calculation is a 

function of the PoD and daily water consumption used to provide the EDWC at the targeted level of 

concern for dietary assessment (≤100% of the PAD). The DWLOC calculation characterizes the

amount of exposure available in the total ‘risk cup’ for the residues of terbufos in drinking water 

irrespective of its exposures from food. It provides a rough estimate to determine the potential need 

for further drinking water refinement of the calculated peak EDWCs determined for assessment. 

Because the sentinel population subgroups of all infants <1 year old and females 13-49 years old have 

the highest exposures to residues in drinking water, mitigating the acute and steady-state risks for 

these population subgroups would therefore be protective of all others. For terbufos, Table 13 shows 

the lowest DWLOC calculated in Attachment 19 was for all infants <1 year old at a peak 

concentration of 0.1093 ppb for the acute and 0.0546 ppb for the steady-state determinations at the 

95th percentile.

 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 18 of 44

Table 13. Acute and Steady-State Calculation of DWLOCs1for Terbufos2

Population Acute Terbufos DWLOC (ppb) Steady-State Terbufos DWLOC (ppb)

General Population 0.37594 0.20367

All Infants <1 years old 0.10929 0.05464

Females 13-49 years old 0.38023 0.20661

1 DWLOC – drinking water level of comparison. 

2 DWLOC: DWLOC (EDWC ppb)= (% aPAD or %ssPAD)(1000ug/mg)(PoD)/(water consumption L/kgBW/day )(100).

3 Concentrations are represented in ppb for the drinking water residues of concern of terbufos parent, and its two oxidative 

degradates terbufos sulfoxide and terbufos sulfone. 

IX. Conclusions

These unrefined analyses demonstrate that the current uses of terbufos will result in acute dietary risk 

estimates for food and drinking water which exceed HED’s level of concern for any of the regulated 

population subgroups, including those comprised of infants and children. Steady-state dietary 

exposure estimates are also above HED’s level of concern for the U.S. population and all population 

subgroups. 

References

DP No.: D258668

Subject: Terbufos. List A Reregistration Case No. 0109/Chemical ID No. 105001. Revised 

Acute and Chronic Dietary Exposure Analysis for the HED Revised Risk Assessment. 

No MRID No. DP Barcode No. D258668. 

From: C. Swartz

To: W. J. Hazel

Dated: 08/26/1999

MRID No.: None

DP No.: D417464

Subject: Terbufos. Report of the Residues of Concern Knowledgebase Subcommittee

(ROCKS). 

From: E. Scollon

To: Terbufos Risk Assessment Team

Dated: 02/03/2014

MRID No.: None

DP No.: D244268

Subject: Terbufos. List A Reregistration Case No. 0109/Chemical ID No. 105001. 

Anticipated Residue Assessment. No MRID No. DP Barcode D244268. 

From: W. J. Hazel

To: C. Swartz/F. Fort

Dated: 03/19/1998

MRID No.: None
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 19 of 44

DP No.: None

Subject: Terbufos Registration Standard

From: C. Trichilo

To: A. Rispin

Dated: 01/19/1983

MRID No.: 00036127, 00036246, 00079431, 00062872, 00042020, 00088211, 00049235, 

00087687, 00036242, 00036241, 00087702, 00087703, and 00087704

DP No.: D419906

Subject: Percent of Banana and Coffee Imports Treated with Terbufos, BEAN DP No. 419906, 

and PC Code # 105001.

From: J. Alsadek

To: P. Savoia

Dated: 06/11/2014

MRID No.: None

DP No.: D418656

Subject: Drinking Water Assessment for the registration Review of Terbufos.

From: F. Khan

To: D. Friedman

Dated: 04/08/2014

MRID No.: None

DP No.: D423572

Subject: Adjusted Time-Series Distribution of Total Toxic Residues for Estimated Drinking 

Water Concentrations Based on Typical Rate of Sorghum for Terbufos 

From: F. Khan

To: D. Friedman, T. Myers, K. Costello, P. Savoia & M. Metzger

Dated: 10/29/2014

MRID No.: None

DP No.: D428089

Subject: Adjusted Time-Series Distribution of the Total Toxic Residues of Terbufos from Use 

on Sorghum to Account for the Theoretical Loading Reduction of Terbufos and its 

Degradates to Surface Water in the Presence of Label-Prescribed Vegetative Buffers.

From: F. Khan

To: M. Manupella, T. Myers, K. Costello, P. Savoia & M. Metzger

Dated: 07/10/2015

MRID No.: None
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 20 of 44

XI. List of Attachments

1. Attachment 1: Terbufos Residue Distribution Files (RDFs) for Existing Food Uses based on 

Field Trial Data and those modeled for Drinking Water based on time-series 

simulation.

2. Attachment 2: Acute (Food + Drinking Water-Max Rate) Residue Input File and Summation of 

the Additional Residue Input Files used for the Characterization of Acute Dietary 

Risk.

3. Attachment 3: Acute Analysis (Food + Drinking Water-Max Rate) Results File.

4. Attachment 4: Acute Analysis (Food only) Results File.

5. Attachment 5: Acute Analysis (Drinking Water only-Max Rate) Results File.

6. Attachment 6: Acute Analysis (Drinking Water only-Typical Rate) Results File.

7. Attachment 7: Acute Analysis (Food + Drinking Water-Typical Rate) Results File.

8. Attachment 8: Acute Analysis (Drinking Water only-Vegetative Buffer Reduction of EDWCs) 

Results File.

9. Attachment 9: Acute Analysis (Food + Drinking Water only-Vegetative Buffer Reduction of 

EDWCs) Results File.

10. Attachment 10: Critical Exposure Contribution (CEC) Analysis for the Acute Analysis of Food + 

Drinking Water-Max Rate of All Infants.

11. Attachment 11: Steady-State Analysis (Food + Drinking Water-Max Rate) Residue Input File 

and Summation of the Additional Residue Input Files used for the 

Characterization of Steady-State Dietary Risk.

12. Attachment 12: Steady-State Analysis (Food + Drinking Water-Max Rate) Results File.

13. Attachment 13: Steady-State Analysis (Food only) Results File.

14. Attachment 14: Steady-State Analysis (Drinking Water only-Max Rate) Results File.

15. Attachment 15: Steady-State Analysis (Drinking Water only-Typical Rate) Results File.

16. Attachment 16: Steady-State Analysis (Food + Drinking Water-Typical Rate) Results File.

17. Attachment 17: Steady-State Analysis (Drinking Water only-Vegetative Buffer Reduction of 

EDWCs) Results File.

18. Attachment 18: Steady-State Analysis (Food + Drinking Water only-Vegetative Buffer 

Reduction of EDWCs) Results File.

19. Attachment 19: DWLOC Calculation for Screening the Dietary Risk Contribution of Terbufos 

from Drinking Water.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 21 of 44

ATTACHMENT 1

Terbufos Residue Distribution Files (RDFs) for Existing Uses based on Field Trial Data

A. Residue Data Files for Food

Terbufos Food Residue Data Files for Acute Dietary Analysis

Banana

(Data File; Banana_pulp_2014Reregistration.rdf

Sweet Corn

Data File; Sweet Corn_100 CT_2014 

Reregistration.rdf

Field trials - Bananas pulp (half lod/loq)

3 g ai and 4 g ai rates 100% CT

totalz=0

0.015

0.005

0.005

0.01

0.005

0.005

0.005

0.001

0.001

0.001

0.001

0.001

0.001

CORN, SWEET 100% CT 

Totalz = 0

Totalnz = 10

0.005

0.005

0.005

0.005

0.005

0.01

0.01

0.01

0.005

0.005

B. Residue Data Files for Drinking Water

For utilization in dietary analysis, EFED generated daily time-series outputs that simulate 29 years (1962-

1990) of terbufos residues in surface drinking water. This modeling used the highest EDWCs determined for 

terbufos which are found to result from the maximum application rate of the Texas sorghum OP scenario. In 

addition, the terbufos time-series developed by EFED was also amended for analysis using a typical sorghum 

application rate (53% of the maximum rate) and a 90% reduction implied through the bounding of residues in 

vegetative buffers to provide for a complete characterization of dietary risk. No further adjustments were 

made to the acute distribution files. Since the two-day average dietary assessments used 21-day rolling 

averages for drinking water, the steady-state distributions were further adjusted by HED to be 21-day rolling 

averages. In the 21-day rolling average distributions, the first data point is the average of days 1-21, the 

second data point is the average of days 2-22, the third data point is the average of days 3-23, etc. The 21-day 

rolling average continues until the last 20 days of residues of the final distribution year (1990). For these 

residues, the average was taken only of the remaining days, resulting in residue values that are not 21-day 

averages. This is not expected to have a large impact on the dietary exposure assessment since the data points 

which are not true 21-day rolling averages represent only 20 days out of 29 years and the simulated drinking 

water estimates do not include applications at the end of the year. 

Dietary assessments were not completed using groundwater values since the peak EDWCs for groundwater 

were substantially lower than for surface waters.

Water Data Files for Acute Analyses

1. Terbufos Texas Surghum_Drinking Water.rdf – Maximum rate data file

2. Terbufos Texas Surghum_Drinking Water_with point 53 multiplier.rdf – Typical rate data file

3. Sorghum_TTR_PCA and 90% reduction adjusted.rdf – Vegetative buffer reduction data file 

Water Data Files for Steady-State Acute 2-Day Analyses

1. DrinkingWaterTerbufosTXsorghumMaxRate Parent plus Metabolites For Acute 2day.rdf – Maximum rate 

data file

2. DrinkingWaterTerbufosTXsorghumTypicalRate with Point 53 Multiplier Parent plus Metabolites For 

Acute 2day.rdf – Typical rate data file
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 22 of 44

3. Sorghum_TTR_PCA and 90% reduction adjusted for 2 day acute.rdf – Vegetative buffer reduction data 

file

ATTACHMENT 2

Acute (Food + Drinking Water-Max Rate) Residue Input File

Filename: E:\Terbufos Dietary\2015 Revised Analyses Using a 10x FQPA Safety Factor\Terbufos Acute 

Files with 10x FQPA_June 2015\105001_Terbufos_Reregistration June 2015_Acute_Food and Water Max 

Rate_100 CT_with 10x FQPA .r08

Chemical: 105001 Terbufos

RfD(Chronic): 0 mg/kg bw/day NOEL(Chronic): 0 mg/kg bw/day

RfD(Acute): .00002 mg/kg bw/day NOEL(Acute): 0 mg/kg bw/day

Date created/last modified: 06-16-2015/11:04:21 Program ver. 3.16, 03-08-d

Comment: 105001 Terbufos Reregistration includes EWDCs and revised PODs with 10x FQPA Safety Factor 

and 100%CT data

-----------------------------------------------------------------------------------

RDL indices and parameters for Monte Carlo Analysis:

Index Dist Parameter #1 Param #2 Param #3 Comment

 # Code 

----- ---- ------------ -------- -------- -------

 1 6 Banana_pulp_2014Reregistration.rdf

 2 6 Sweet Corn_100 CT_2014 Reregistration.rdf

 3 6 Terbufos Texas Surghum_Drinking Water.rdf

 EPA Crop Commodity Name Def Res Adj.Factors RDLComment

 Code Grp (ppm) #1 #2 Pntr

---------- ---- ------------------------------- ---------- ------ ------ --- -------

0101052000 1A Beet, sugar 0.025000 1.000 1.000 

0101052001 1A Beet, sugar-babyfood 0.025000 1.000 1.000 

1500120000 15 Corn, field, flour 0.005000 1.000 1.000 

1500120001 15 Corn, field, flour-babyfood 0.005000 1.000 1.000 

1500121000 15 Corn, field, meal 0.005000 1.000 1.000 

1500121001 15 Corn, field, meal-babyfood 0.005000 1.000 1.000 

1500122000 15 Corn, field, bran 0.005000 1.000 1.000 

1500123000 15 Corn, field, starch 0.005000 1.000 1.000 

1500123001 15 Corn, field, starch-babyfood 0.005000 1.000 1.000 

1500124000 15 Corn, field, syrup 0.005000 1.500 1.000 

1500124001 15 Corn, field, syrup-babyfood 0.005000 1.500 1.000 

1500125000 15 Corn, field, oil 0.005000 1.000 1.000 

1500125001 15 Corn, field, oil-babyfood 0.005000 1.000 1.000 

1500126000 15 Corn, pop 0.005000 1.000 1.000 

1500127000 15 Corn, sweet 0.005000 1.000 1.000 2 

1500127001 15 Corn, sweet-babyfood 0.005000 1.000 1.000 2 

1500344000 15 Sorghum, grain 0.025000 1.000 1.000 

8601000000 86A Water, direct, all sources 0.063060 1.000 1.000 3 

8602000000 86B Water, indirect, all sources 0.063060 1.000 1.000 3 

9500023000 O Banana 0.025000 1.000 1.000 1 

9500023001 O Banana-babyfood 0.025000 1.000 1.000 1 

9500024000 O Banana, dried 0.004300 3.900 1.000 

9500024001 O Banana, dried-babyfood 0.004300 3.900 1.000 

9500115000 O Coffee, roasted bean 0.028000 1.000 1.000 

9500116000 O Coffee, instant 0.028000 1.000 1.000 

9500283000 O Plantain 0.025000 1.000 1.000 1 

9500284000 O Plantain, dried 0.004300 3.900 1.000 

Additional Residue Input Files used for the Characterization of Acute Dietary Risk

To provide for the complete characterization of acute dietary risk, analyses were also made which considered 

EDWCs determined using a typical rate of application as well as a 90% implied reduction of EDWCs through 

bounding in vegetative buffers. For each scenario, food only, drinking water only, and food plus drinking 

water were determined using derivatives of the Acute (Food + Drinking Water-Max Rate) Residue Input File.

Residue Input Files used for Acute Dietary Characterization

1. 105001_Terbufos_Reregistration June 2015_Acute_Food only_100 CT_with 10x FQPA.r08

2. 105001_Terbufos_Reregistration June 2015_Acute_Water Max Rate only_with 10x FQPA .r08

3. 105001_Terbufos_Reregistration June 2015_Acute_Water Typical Rate only_with point 53 

multiplier_with 10x FQPA.r08
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 23 of 44

4. 105001_Terbufos_Reregistration June 2015_Acute_Food and Water Typical Rate_100 CT_with point 53 

multiplier_with 10x FQPA.r08

5. 105001_Terbufos_Reregistration June 2015_Acute_Water only using 90% Reduced EDWCs for a Vegetative 

Buffer_with 10x FQPA .r08

6. 105001_Terbufos_Reregistration June 2015_Acute_Food and Water using 90% Reduced EDWCs for a 

Vegetative Buffer_100 CT_with 10x FQPA .r08

 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 24 of 44

ATTACHMENT 3

Acute Analysis (Food + Drinking Water-Max Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration June 2015_Acute_Food and Water Max Rate_

100 CT_with 10x FQPA .r08

 Adjustment factor #2 used.

Analysis Date: 06-16-2015/11:40:21 Residue file dated: 06-16-2015/11:04:21

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

RAC/FF intake summed over 24 hours

MC iterations = 1000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000389 1947.15 0.001103 5513.49 0.003205 >10000 

All Infants:

 0.001055 5273.27 0.003177 >10000 0.009678 >10000 

Female 13-50:

 0.000387 1936.15 0.001090 5447.67 0.003103 >10000 

Children 1-2:

 0.000587 2934.96 0.001658 8291.71 0.004974 >10000 

Children 3-5:

 0.000502 2509.14 0.001360 6799.84 0.003915 >10000 

Children 6-12:

 0.000359 1793.60 0.000998 4992.11 0.002941 >10000 

Youth 13-19:

 0.000289 1447.26 0.000843 4216.85 0.002529 >10000 

Adults 20-49:

 0.000388 1939.89 0.001086 5429.74 0.003082 >10000 

Adults 50-99:

 0.000378 189.23 0.001031 515.50 0.002842 1421.19 

Female 13-49:

 0.000387 1934.76 0.001090 5449.42 0.003106 >10000 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 25 of 44

ATTACHMENT 4

Acute Analysis (Food only) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration June 2015_Acute_Food only_100 CT_with

10x FQPA.r08

 Adjustment factor #2 used.

Analysis Date: 06-16-2015/11:22:59 Residue file dated: 06-16-2015/11:03:02

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

RAC/FF intake summed over 24 hours

MC iterations = 1000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

 Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000056 281.90 0.000098 489.74 0.000173 866.50 

All Infants:

 0.000122 611.47 0.000181 903.48 0.000366 1831.44 

Female 13-50:

 0.000040 200.93 0.000060 301.31 0.000096 481.86

Children 1-2:

 0.000126 631.99 0.000197 986.74 0.000419 2094.02 

Children 3-5:

 0.000109 544.03 0.000152 758.73 0.000223 1115.74 

Children 6-12:

 0.000079 393.68 0.000120 599.89 0.000174 871.47 

Youth 13-19:

 0.000049 244.39 0.000072 358.49 0.000123 616.37 

Adults 20-49:

 0.000042 210.85 0.000063 316.43 0.000103 512.55 

Adults 50-99:

 0.000035 17.54 0.000052 26.20 0.000080 40.00 

Female 13-49:

 0.000040 200.39 0.000060 299.17 0.000096 482.46 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 26 of 44

ATTACHMENT 5

Acute Analysis (Drinking Water only-Max Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration June 2015_Acute_Water Max Rate only

_with 10x FQPA .r08

 Adjustment factor #2 used.

Analysis Date: 06-16-2015/11:31:07 Residue file dated: 06-16-2015/11:03:49

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

RAC/FF intake summed over 24 hours

MC iterations = 1000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000366 1832.39 0.001075 5373.07 0.003167 >10000 

All Infants:

 0.001020 5098.54 0.003171 >10000 0.009774 >10000 

Female 13-50:

 0.000371 1853.18 0.001069 5344.72 0.003077 >10000 

Children 1-2:

 0.000527 2634.30 0.001575 7876.23 0.004743 >10000 

Children 3-5:

 0.000450 2251.79 0.001324 6618.07 0.003875 >10000 

Children 6-12:

 0.000323 1616.45 0.000963 4812.94 0.002884 >10000 

Youth 13-19:

 0.000269 1345.00 0.000823 4114.29 0.002516 >10000 

Adults 20-49:

 0.000370 1852.42 0.001062 5311.48 0.003042 >10000 

Adults 50-99:

 0.000362 180.90 0.001009 504.48 0.002797 1398.38 

Female 13-49:

 0.000370 1851.95 0.001070 5348.03 0.003081 >10000 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 27 of 44

ATTACHMENT 6

Acute Analysis (Drinking Water only-Typical Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration June 2015_Acute_Water Typical Rate only

_with point 53 multiplier.r08

 Adjustment factor #2 used.

Analysis Date: 06-16-2015/12:30:03 Residue file dated: 06-16-2015/11:05:31

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

RAC/FF intake summed over 24 hours

MC iterations = 1000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes Typical Rate EWDCs and 

revised PODs with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000195 975.20 0.000578 2888.20 0.001710 8551.01 

All Infants:

 0.000543 2716.64 0.001705 8526.96 0.005129 >10000 

Female 13-50:

 0.000197 985.40 0.000574 2869.08 0.001663 8316.21 

Children 1-2:

 0.000281 1405.01 0.000860 4297.74 0.002618 >10000 

Children 3-5:

 0.000239 1194.84 0.000705 3526.92 0.002102 >10000 

Children 6-12:

 0.000171 856.58 0.000519 2596.23 0.001549 7745.36 

Youth 13-19:

 0.000143 716.94 0.000446 2229.16 0.001360 6801.10 

Adults 20-49:

 0.000197 984.63 0.000571 2855.07 0.001647 8236.17 

Adults 50-99:

 0.000193 96.42 0.000542 270.91 0.001504 752.09 

Female 13-49:

 0.000197 984.95 0.000575 2873.05 0.001667 8334.95 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 28 of 44

ATTACHMENT 7

Acute Analysis (Food + Drinking Water only-Typical Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration June 2015_Acute_Food and Water Typical 

Rate_100 CT_with point 53 multiplier.r08

 Adjustment factor #2 used.

Analysis Date: 06-16-2015/12:48:35 Residue file dated: 06-16-2015/11:06:26

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

RAC/FF intake summed over 24 hours

MC iterations = 1000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes Typical Rate EWDCs and 

revised PODs with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

 Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000220 1099.30 0.000604 3021.87 0.001731 8657.00 

All Infants:

 0.000580 2900.82 0.001721 8606.64 0.005117 >10000 

Female 13-50:

 0.000214 1069.87 0.000595 2973.34 0.001686 8429.60 

Children 1-2:

 0.000347 1733.50 0.000926 4629.14 0.002691 >10000 

Children 3-5:

 0.000294 1471.55 0.000765 3824.49 0.002149 >10000 

Children 6-12:

 0.000212 1059.67 0.000557 2784.14 0.001595 7977.33 

Youth 13-19:

 0.000165 824.45 0.000464 2321.91 0.001375 6874.00 

Adults 20-49:

 0.000215 1074.78 0.000592 2959.54 0.001667 8332.95 

Adults 50-99:

 0.000209 104.72 0.000561 280.49 0.001510 754.83 

Female 13-49:

 0.000214 1068.66 0.000594 2972.16 0.001689 8445.64 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 29 of 44

ATTACHMENT 8

Acute Analysis (Drinking Water only-Vegetative Buffer Reduction of EDWCs) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration June 2015_Acute_Water only using 90% 

Reduced EDWCs for a Vegetative Buffer_with 10x FQPA .r08

 Adjustment factor #2 used.

Analysis Date: 06-16-2015/14:08:16 Residue file dated: 06-16-2015/11:09:20

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

RAC/FF intake summed over 24 hours

MC iterations = 1000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000037 183.24 0.000107 537.31 0.000317 1583.61 

All Infants:

 0.000102 509.85 0.000317 1585.39 0.000977 4886.84 

Female 13-50:

 0.000037 185.32 0.000107 534.47 0.000308 1538.64 

Children 1-2:

 0.000053 263.43 0.000158 787.62 0.000474 2371.27 

Children 3-5:

 0.000045 225.18 0.000132 661.81 0.000387 1937.35 

Children 6-12:

 0.000032 161.64 0.000096 481.29 0.000288 1441.96 

Youth 13-19:

 0.000027 134.50 0.000082 411.43 0.000252 1258.11 

Adults 20-49:

 0.000037 185.24 0.000106 531.15 0.000304 1520.89 

Adults 50-99:

 0.000036 18.09 0.000101 50.45 0.000280 139.84 

Female 13-49:

 0.000037 185.19 0.000107 534.80 0.000308 1540.67 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 30 of 44

ATTACHMENT 9

Acute Analysis (Food + Drinking Water only-Vegetative Buffer Reduction of EDWCs) Results 

File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration June 2015_Acute_Food and Water using 

90% Reduced EDWCs for a Vegetative Buffer_100 CT_with 10x FQPA .r08

 Adjustment factor #2 used.

Analysis Date: 06-16-2015/14:43:10 Residue file dated: 06-16-2015/11:10:25

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

RAC/FF intake summed over 24 hours

MC iterations = 1000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000079 396.59 0.000153 763.64 0.000359 1794.04 

All Infants:

 0.000175 873.39 0.000377 1884.59 0.001023 5116.57 

Female 13-50:

 0.000063 314.07 0.000128 641.28 0.000328 1639.86 

Children 1-2:

 0.000157 787.32 0.000271 1353.46 0.000635 3174.25 

Children 3-5:

 0.000133 664.16 0.000213 1062.54 0.000449 2243.23 

Children 6-12:

 0.000095 477.08 0.000159 796.29 0.000338 1689.64 

Youth 13-19:

 0.000064 318.45 0.000118 588.55 0.000275 1374.41 

Adults 20-49:

 0.000064 321.22 0.000130 648.56 0.000327 1634.87 

Adults 50-99:

 0.000059 29.43 0.000122 60.84 0.000302 151.22 

Female 13-49:

 0.000063 313.13 0.000128 640.74 0.000328 1641.01 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 31 of 44

ATTACHMENT 10

Critical Exposure Contribution (CEC) Analysis for the Acute Analysis of Food + Drinking 

Water –Max Rate of All Infants

All Infants

Low percentile for CEC records: 99.9 Exposure (mg/day) = 0.009678

High percentile for CEC records: 100 Exposure (mg/day) = 0.033353

Number of actual records in this interval: 2251

Critical foods with foodforms for this population (as derived from these records):

 N=number of appearances in all records (including duplicates)

 %=percent of total exposure for all records (including duplicates)

Food FF N Percent Food Name 

---------- --- ----- ------- -------------

8.6E+09 130 1902 77.20% Water indirect all sources-Uncooked; Dried; Cook Meth N/S

8.6E+09 110 811 7.79% Water direct all sources-Uncooked; Fresh or N/S; Cook Meth N/S

8.6E+09 240 185 6.18% Water indirect all sources-Cooked; Canned; Cook Meth N/S

8.6E+09 230 189 6.15% Water indirect all sources-Cooked; Dried; Cook Meth N/S

8.6E+09 110 320 1.72% Water indirect all sources-Uncooked; Fresh or N/S; Cook Meth N/S

8.6E+09 232 98 0.39% Water indirect all sources-Cooked; Dried; Boiled

8.6E+09 212 59 0.14% Water indirect all sources-Cooked; Fresh or N/S; Boiled

8.6E+09 210 7 0.02% Water indirect all sources-Cooked; Fresh or N/S; Cook Meth N/S

8.6E+09 242 7 0.01% Water indirect all sources-Cooked; Canned; Boiled

9.5E+09 240 4 0.01% Banana-babyfood-Cooked; Canned; Cook Meth N/S

Critical foods (without foodforms) for this population (as derived from these records):

 N=number of appearances in all records (including duplicates)

 %=percent of total exposure for all records (including duplicates)

Food N Percent Food Name 

---------- ----- ------- -------------

8.6E+09 2767 91.81% Water indirect all sources

8.6E+09 811 7.79% Water direct all sources

9.5E+09 4 0.01% Banana-babyfood

Number of printed records = 10 

Number of records represented = 12 

(nf = number of foods/ff reported for this daily exposure amount (exceeding minimum contribution)

(nx = number of times this exposure amount was computed for the same person on the same day.)
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 32 of 44

ATTACHMENT 11

Steady-State Analysis (Food + Drinking Water-Max Rate) Residue Input File

Filename: E:\Terbufos Dietary\2015 Revised Analyses Using a 10x FQPA Safety Factor\Terbufos 2 Day 

Acute Files with 10x FQPA June 2015\105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady 

State_Food only_100 CT_with 10x FQPA.r08

Chemical: 105001 Terbufos

RfD(Chronic): 0 mg/kg bw/day NOEL(Chronic): 0 mg/kg bw/day

RfD(Acute): .00001 mg/kg bw/day NOEL(Acute): 0 mg/kg bw/day

Date created/last modified: 06-17-2015/14:18:51 Program ver. 3.16, 03-08-d

Comment: 105001 Terbufos Reregistration includes EWDCs and revised PODs with a 10x FQPA Safety Factor 

and 100%CT data

-----------------------------------------------------------------------------------

RDL indices and parameters for Monte Carlo Analysis:

Index Dist Parameter #1 Param #2 Param #3 Comment

 # Code 

----- ---- ------------ -------- -------- -------

 1 6 Banana_pulp_2014Reregistration.rdf

 2 6 Sweet Corn_100 CT_2014 Reregistration.rdf

 3 6 DrinkingWaterTerbufosTXsorghumMaxRate Parent plus Metabolites For Acute 2day.rdf

 EPA Crop Commodity Name Def Res Adj.Factors RDLComment

 Code Grp (ppm) #1 #2 Pntr

---------- ---- ------------------------------- ---------- ------ ------ --- -------

0101052000 1A Beet, sugar 0.025000 1.000 1.000 

0101052001 1A Beet, sugar-babyfood 0.025000 1.000 1.000 

1500120000 15 Corn, field, flour 0.005000 1.000 1.000 

1500120001 15 Corn, field, flour-babyfood 0.005000 1.000 1.000 

1500121000 15 Corn, field, meal 0.005000 1.000 1.000 

1500121001 15 Corn, field, meal-babyfood 0.005000 1.000 1.000 

1500122000 15 Corn, field, bran 0.005000 1.000 1.000 

1500123000 15 Corn, field, starch 0.005000 1.000 1.000 

1500123001 15 Corn, field, starch-babyfood 0.005000 1.000 1.000 

1500124000 15 Corn, field, syrup 0.005000 1.500 1.000 

1500124001 15 Corn, field, syrup-babyfood 0.005000 1.500 1.000 

1500125000 15 Corn, field, oil 0.005000 1.000 1.000 

1500125001 15 Corn, field, oil-babyfood 0.005000 1.000 1.000 

1500126000 15 Corn, pop 0.005000 1.000 1.000 

1500127000 15 Corn, sweet 0.005000 1.000 1.000 2 

1500127001 15 Corn, sweet-babyfood 0.005000 1.000 1.000 2 

1500344000 15 Sorghum, grain 0.025000 1.000 1.000 

9500023000 O Banana 0.025000 1.000 1.000 1 

9500023001 O Banana-babyfood 0.025000 1.000 1.000 1 

9500024000 O Banana, dried 0.004300 3.900 1.000 

9500024001 O Banana, dried-babyfood 0.004300 3.900 1.000 

9500115000 O Coffee, roasted bean 0.028000 1.000 1.000 

9500116000 O Coffee, instant 0.028000 1.000 1.000 

9500283000 O Plantain 0.025000 1.000 1.000 1 

9500284000 O Plantain, dried 0.004300 3.900 1.000 

Additional Residue Input Files used for the characterization of Steady-State Dietary Risk

To provide for the complete characterization of the steady-state dietary risk, analyses were also made which 

considered EDWCs determined using a typical rate of application as well as a 90% implied reduction of 

EDWCs through bounding in vegetative buffers. For each scenario, food only, drinking water only, and food 

plus drinking water were determined using derivatives of the Acute (Food + Drinking Water-Max Rate) 

Residue Input File.

Acute 2-Day Analysis Residue Input Files used for Steady-State Dietary Characterization

1. 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_Food only_100 CT_with 10x

FQPA.r08

2. 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_Water only_Max Rate_with 10x

FQPA.r08

3. 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_Water only_Typical Rate with 

point 53 multiplier_with a 10x FQPA.r08
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 33 of 44

4. 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_Food 100 CT and Water Typical 

Rate with point 53 multiplier_with a 10x FQPA.r08

5. 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_Water only using 90% Reduced 

EDWCs for a Vegetative Buffer_with 10x FQPA.r08

6. 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_Food 100 CT and Water using 90% 

Reduced EDWCs for a Vegetative Buffer_with a 10x FQPA.r08
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 34 of 44

ATTACHMENT 12

Steady-State Analysis (Food + Drinking Water-Max Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_

Food and Water Max Rate_100 CT_with 10xFQPA.r08

 Adjustment factor #2 used.

Analysis Date: 07-22-2015/07:13:22 Residue file dated: 06-17-2015/13:43:24

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

Two-Day Average Results Reported

RAC/FF intake summed over 24 hours

MC iterations = 2000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000380 3796.30 0.001023 >10000 0.002764 >10000 

All Infants:

 0.001038 >10000 0.002962 >10000 0.008518 >10000 

Children 1-2:

 0.000574 5737.53 0.001516 >10000 0.004234 >10000 

Children 3-5:

 0.000486 4863.65 0.001255 >10000 0.003311 >10000 

Children 6-12:

 0.000350 3504.11 0.000923 9233.28 0.002488 >10000 

Youth 13-19:

 0.000284 2836.49 0.000777 7768.37 0.002166 >10000 

Adults 20-49:

 0.000377 3772.85 0.001001 >10000 0.002624 >10000 

Adults 50-99:

 0.000368 367.87 0.000965 964.61 0.002472 2471.99 

Female 13-49:

 0.000378 3775.73 0.001005 >10000 0.002672 >10000 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 35 of 44

ATTACHMENT 13

Steady-State Analysis (Food only) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_

Food only_100 CT_with 10xFQPA.r08

 Adjustment factor #2 used.

Analysis Date: 07-22-2015/07:23:16 Residue file dated: 06-17-2015/14:18:51

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

Two-Day Average Results Reported

RAC/FF intake summed over 24 hours

MC iterations = 2000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000053 531.77 0.000089 891.85 0.000148 1482.88 

All Infants:

 0.000111 1109.99 0.000161 1606.25 0.000283 2833.39 

Children 1-2:

 0.000113 1130.51 0.000173 1733.20 0.000303 3026.76 

Children 3-5:

 0.000097 966.06 0.000134 1340.33 0.000182 1818.91 

Children 6-12:

 0.000072 721.82 0.000103 1032.55 0.000132 1319.61 

Youth 13-19:

 0.000044 435.87 0.000062 622.75 0.000121 1207.98 

Adults 20-49:

 0.000039 386.35 0.000055 547.31 0.000088 882.69 

Adults 50-99:

 0.000032 32.28 0.000046 46.43 0.000065 64.79 

Female 13-49:

 0.000037 366.55 0.000052 517.92 0.000088 882.76 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 36 of 44

ATTACHMENT 14

Steady-State Analysis (Drinking Water only-Max Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_

Water only_Max Rate_with 10xFQPA.r08

 Adjustment factor #2 used.

Analysis Date: 07-22-2015/07:29:14 Residue file dated: 06-17-2015/13:48:51

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

Two-Day Average Results Reported

RAC/FF intake summed over 24 hours

MC iterations = 2000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000357 3567.51 0.000997 9969.18 0.002748 >10000 

All Infants:

 0.000999 9986.03 0.002932 >10000 0.008515 >10000 

Children 1-2:

 0.000517 5169.20 0.001456 >10000 0.004146 >10000 

Children 3-5:

 0.000436 4357.00 0.001207 >10000 0.003203 >10000 

Children 6-12:

 0.000314 3135.35 0.000882 8821.89 0.002432 >10000 

Youth 13-19:

 0.000263 2626.75 0.000752 7519.61 0.002125 >10000 

Adults 20-49:

 0.000360 3597.68 0.000981 9814.27 0.002620 >10000 

Adults 50-99:

 0.000351 351.27 0.000946 946.32 0.002489 2488.90 

Female 13-49:

 0.000359 3593.83 0.000987 9865.37 0.002680 >10000 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 37 of 44

ATTACHMENT 15

Steady-State Analysis (Drinking Water only-Typical Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_

Water only_Typical Rate with point 53 multiplier_with a 10xFQPA.r08

 Adjustment factor #2 used.

Analysis Date: 07-22-2015/07:59:33 Residue file dated: 06-17-2015/13:49:43

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

Two-Day Average Results Reported

RAC/FF intake summed over 24 hours

MC iterations = 2000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000189 1890.83 0.000528 5283.27 0.001456 >10000 

All Infants:

 0.000529 5292.04 0.001554 >10000 0.004513 >10000 

Children 1-2:

 0.000274 2739.34 0.000772 7716.19 0.002198 >10000 

Children 3-5:

 0.000231 2309.31 0.000640 6396.50 0.001698 >10000 

Children 6-12:

 0.000166 1661.62 0.000467 4674.47 0.001290 >10000 

Youth 13-19:

 0.000139 1392.20 0.000398 3984.99 0.001127 >10000 

Adults 20-49:

 0.000191 1906.68 0.000520 5201.70 0.001389 >10000 

Adults 50-99:

 0.000186 186.17 0.000502 501.59 0.001319 1319.38 

Female 13-49:

 0.000190 1904.64 0.000523 5228.83 0.001420 >10000 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 38 of 44

ATTACHMENT 16

Steady-State Analysis (Food + Drinking Water-Typical Rate) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_

Food 100 CT and Water Typical Rate with point 53 multiplier_with a 10xFQPA.r08

 Adjustment factor #2 used.

Analysis Date: 07-22-2015/08:08:46 Residue file dated: 06-17-2015/13:52:38

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

Two-Day Average Results Reported

RAC/FF intake summed over 24 hours

MC iterations = 2000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

 Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000213 2133.27 0.000554 5543.06 0.001479 >10000 

All Infants:

 0.000569 5689.89 0.001587 >10000 0.004541 >10000 

Children 1-2:

 0.000335 3346.96 0.000837 8371.14 0.002275 >10000 

Children 3-5:

 0.000284 2835.66 0.000690 6903.94 0.001785 >10000 

Children 6-12:

 0.000205 2046.13 0.000508 5078.13 0.001338 >10000 

Youth 13-19:

 0.000161 1607.37 0.000422 4216.66 0.001159 >10000 

Adults 20-49:

 0.000209 2085.82 0.000539 5393.24 0.001400 >10000 

Adults 50-99:

 0.000203 202.76 0.000519 519.44 0.001319 1318.95 

Female 13-49:

 0.000208 2083.21 0.000541 5407.18 0.001423 >10000 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 39 of 44

ATTACHMENT 17

Steady-State Analysis (Drinking Water only- Vegetative Buffer Reduction of EDWCs) Results 

File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_

Water only using 90% Reduced EDWCs for a Vegetative Buffer_with 10xFQPA.r08

 Adjustment factor #2 used.

Analysis Date: 07-22-2015/08:14:30 Residue file dated: 06-17-2015/13:55:06

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

Two-Day Average Results Reported

RAC/FF intake summed over 24 hours

MC iterations = 2000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000036 356.72 0.000100 996.81 0.000275 2747.93 

All Infants:

 0.000100 998.31 0.000293 2930.31 0.000853 8530.06 

Children 1-2:

 0.000052 517.17 0.000146 1457.02 0.000415 4150.46 

Children 3-5:

 0.000044 435.62 0.000121 1205.25 0.000320 3202.30 

Children 6-12:

 0.000031 313.55 0.000088 882.57 0.000243 2430.19 

Youth 13-19:

 0.000026 262.70 0.000075 751.71 0.000213 2126.43 

Adults 20-49:

 0.000036 359.82 0.000098 981.29 0.000262 2621.38 

Adults 50-99:

 0.000035 35.13 0.000095 94.62 0.000249 248.75 

Female 13-49:

 0.000036 359.48 0.000099 986.54 0.000268 2682.21 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 40 of 44

ATTACHMENT 18

Steady-State Analysis (Food plus Drinking Water only- Vegetative Buffer Reduction of 

EDWCs) Results File

US EPA Ver. 3.18, 03-08-d

DEEM-FCID ACUTE Analysis for 105001 TERBUFOS NHANES 2003-2008 2-Day

Residue file: 105001_Terbufos_Reregistration_June 2015_Acute 2 Day Steady State_

Food 100 CT and Water using 90% Reduced EDWCs for a Vegetative Buffer_with a 

10xFQPA.r08

 Adjustment factor #2 used.

Analysis Date: 07-22-2015/08:23:19 Residue file dated: 06-17-2015/13:58:37

Acute Pop Adjusted Dose (aPAD) varies with population; see individual reports

Two-Day Average Results Reported

RAC/FF intake summed over 24 hours

MC iterations = 2000; MC list in residue file; MC seed = 10281; RNG = MS VB

Run Comment: "105001 Terbufos Reregistration includes EWDCs and revised PODs 

with a 10x FQPA Safety Factor and 100%CT data"

===============================================================================

Summary calculations--per capita:

 95th Percentile 99th Percentile 99.9th Percentile

Exposure % aPAD Exposure % aPAD Exposure % aPAD 

 ---------- -------- ---------- -------- ---------- --------

Total US Population:

 0.000075 751.08 0.000139 1391.06 0.000310 3099.00 

All Infants:

 0.000164 1639.16 0.000344 3441.93 0.000894 8937.41 

Children 1-2:

 0.000144 1441.67 0.000245 2447.54 0.000538 5377.85 

Children 3-5:

 0.000119 1192.50 0.000188 1882.67 0.000383 3834.69 

Children 6-12:

 0.000089 891.11 0.000140 1395.06 0.000289 2894.32 

Youth 13-19:

 0.000058 584.20 0.000107 1071.02 0.000238 2375.67 

Adults 20-49:

 0.000061 605.63 0.000118 1184.57 0.000281 2806.57 

Adults 50-99:

 0.000056 55.55 0.000114 113.75 0.000265 265.29 

Female 13-49:

 0.000059 588.89 0.000118 1178.96 0.000283 2834.43 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 41 of 44

ATTACHMENT 19

DWLOC Calculation for Screening the Dietary Risk Contribution of Terbufos from Drinking 

Water

Screening of the Dietary Risk Contribution from Drinking Water

This tool aims to provide a quick estimate of the contribution of pesticide residues in drinking water to the dietary risk 

pesticide. This screening level tool is designed to provide rough estimates that are helpful to determine the potential n

further refinement of the estimated drinking water concentration (EDWC). Food and residential exposures are not 

considered; therefore, even if estimated DW risks are relatively low, aggregate risk concerns may still result, and refine

to the DW residue estimates may still be necessary. The formulas used to estimate the dietary risk are presented below

HED’s toxicologist and/or risk assessor would be able to provide the acute, steady state and/or chronic population adju

dose in mg ai/kg-bw/day, the cancer Q* in (mg ai/kg-bw/day)-1 and information about the level of refinement (if percen

crop treated assumptions are made). EFED’s drinking water assessor would be able to provide the EDWC for acute/st

state, chronic or cancer assessments expressed in terms of the pesticide, e.g. residues of acephate and it degradate 

methamidophos expressed as parent acephate. The water consumption values (see Input Values tab) were obtained u

dietary exposure and risk model, DEEM-FCID Version 4.02, which uses food consumption data from the USDA National 

and Nutrition Examination Survey, What We Eat in America, conducted from 2005 to 2010. In general, the population 

subgroup with higher exposure to residues in drinking water is infants (<1 yr old); therefore, acute or chronic risks for t

subgroup would be protective of other subgroups. Occasionally, a different PAD is selected for females in reproductive 

other population subgroups. In such case a separate calculation for that population subgroup would be needed. 

Screening of the Dietary Risk Contribution from Drinking Water

This tool aims to provide a quick estimate of the contribution of pesticide residues in drinking water to the 

dietary risk of the pesticide. This screening level tool is designed to provide rough estimates that are helpful to 

determine the potential need for further refinement of the estimated drinking water concentration (EDWC). 

Food and residential exposures are not considered; therefore, even if estimated DW risks are relatively low, 

aggregate risk concerns may still result, and refinement to the DW residue estimates may still be necessary. 

The formulas used to estimate the dietary risk are presented below.

%aPAD, %ssPAD or %cPAD (Water) = (Water Consumption, L/kgbw/day) (EDWC, ppb) x 100

(1000 ug/mg) (aPAD, ssPAD or cPAD, mg/kg/day)

%aPAD, %ssPAD or %cPAD Water =

 Water Consumption, L/kgbw/day EDWC, ppb 

 1000 μg

mg (aPAD, ssPAD or cPAD, mg/kg/day)

x100
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 42 of 44

Therefore; EDWC, ppb = (%aPAD, %ssPAD or %cPAD) (1000 ug/mg) (aPAD, ssPAD or cPAD, mg/kg/day)

(Water Consumption, L/kgbw/day) (100)

Example; EDWC, ppb Gen. Pop. aPAD 0f 100 = (100) (1000 ug/mg) (0.00002 mg/kg/day) = 0.37594

(0.0532) (100)

HED’s toxicologist and/or risk assessor would be able to provide the acute, steady state and/or chronic 

population adjusted dose in mg ai/kg-bw/day, the cancer Q* in (mg ai/kg-bw/day)-1 and information about the 

level of refinement (if percent of crop treated assumptions are made). EFED’s drinking water assessor would 

be able to provide the EDWC for acute/steady state, chronic or cancer assessments expressed in terms of the 

pesticide, e.g. residues of acephate and it degradate methamidophos expressed as parent acephate. The water 

consumption values (see Input Values tab) were obtained using the dietary exposure and risk model, DEEMFCID Version 4.02, which uses food consumption data from the USDA National Health and Nutrition 

Examination Survey, What We Eat in America, conducted from 2005 to 2010. In general, the population 

subgroup with higher exposure to residues in drinking water is infants (<1 yr old); therefore, acute or chronic 

risks for this subgroup would be protective of other subgroups. Occasionally, a different PAD is selected for 

females in reproductive age or other population subgroups. In such case a separate calculation for that 

population subgroup would be needed. 
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 43 of 44

Risk is f(Toxicity, Exposure)

Toxicity Input Values

HED's risk assessor or toxicologist would be able to provide the safe dietary intake(s) to be considered for 

dietary assessments. In cases that the chemical toxicology database will be re-evaluated the division may 

not be able to provide these values. 

(1) The exposure of the general population is used for cancer risk assessments. 

(2) The population subgroup with highest exposure to drinking water is All Infants (<1 yr old). Generally, a risk calculation for All 

Infants will cover the risk of other subgroups and the general population. In the case that a separate endpoint is available for females in 

reproductive age (13-49 yrs) then the water consumption for that population subgroup should be used to estimate the risk. 

(3) The water consumption for steady state was obtained using the two-day average consumption from individuals participating in the 

WWEIA survey. The EDWC used for steady state screening may be the same used for acute exposure or that corresponding to the 21-

day average.
Terbufos Aggregate Dietary Exposure Assessment DP No. D422672

Page 44 of 44

Value Units 95th 99.9th 95th 99.9th

63.06 General 0.00002 mg/kg/day 16773.96 56754 %aPAD 0.37594 0.111111

63.06 All Infants 0.00002 mg/kg/day 57699.9 107202 %aPAD 0.10929 0.058824

63.06 Females 0.00002 mg/kg/day 16584.78 36259.5 %aPAD 0.380228 0.173913

63.06 General 0.00001 mg/kg/day 30962.46 110355 %ssPAD 0.203666 0.057143

63.06 All Infants 0.00001 mg/kg/day 115399.8 187288.2 %ssPAD 0.054645 0.03367

63.06 Females 0.00001 mg/kg/day 30521.04 59528.64 %ssPAD 0.206612 0.105932

General mg/kg/day %cPAD 0

All Infants mg/kg/day %cPAD 0

Females mg/kg/day %cPAD 0

Cancer General (mg/kg/day)-1 0.00E+00

Screening of the Dietary Risk Contribution from Drinking Water

Please, populate the values in the yellow cells.

Acute

Chronic

Dietary Risk (Water Only)

Acute/Steady State(1) Chronic 

or Cancer

Units

Acute/Steady State Chronic or 

Cancer

Assessment EDWC (ppb) Population aPAD, ssPAD, cPAD or Q*

Steady 

State

EDWC at Level of Concern (ppb)(2)

%aPAD, %ssPAD or %cPAD > 100% - Drinking water assessor considers refinement. 

%aPAD, %ssPAD or %cPAD < 100% - Dietary assessor aggregates exposure through drinking water, food 

and residential uses and communicates concerns to the drinking water assessor if necessary. 

This screening level tool is designed to provide rough estimates to determine the potential need for 

further refinement of the estimated drinking water concentration (EDWC). The risk and EDWC at the LOC 

estimates do not consider exposure through food and residential uses. If the risk estimate is below or 

close to the LOC, please, communicate with HED's risk assessor to determine the contribution of food and 

residential uses to the aggregate risk. 

Implementation

(1) The acute and steady state risks are regulated at the 95th percentile if 100% of the crop is assumed to be treated and at the 99.9th 

percentile if percent of crop treated assumptions provided by the Biological and Economic Analysis Division are incorporated. 

(2) The EDWC at the level of concern estimated by this method is calculated by assuming a risk of 100% of the aPAD, ssPAD or cPAD, or a 

cancer risk of 3x10-6. Thus, all the dietary risk is attributed to exposure through drinking water.