  SEQ CHAPTER \h \r 1 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460      

	OFFICE OF PREVENTION, PESTICIDES

                                                                        
                   AND TOXIC SUBSTANCES

	

MEMORANDUM

Date:  		8/18/09  

SUBJECT:	Chlorimuron ethyl.  Chronic Aggregate Dietary (Food and
Drinking Water) Exposure and Risk Assessment for the Section 3
Registration Action on Field Corn and Soybean.

PC Code:  128901  	DP Barcode:  365815

Decision No.:  400389	Registration No.:  352-436 

Petition No.: 8F7430 & 8F7439	Regulatory Action:  Section 3 Registration

Risk Assessment Type:  Dietary 	Case No.:  NA

TXR No.:  NA 	CAS No.:  90982-32-4

MRID No.:  NA 	40 CFR:  180.429



FROM:		W. Cutchin, Acting Senior Branch Scientist 

		Alternative Risk Integration and Assessment (ARIA)

		Risk Integration, Minor Use, and Emergency Response Branch (RIMUERB)

		Registration Division (RD; 7505P)

THRU:		Y. Barnes, Chemist

		N. Dodd, Chemist

		Dietary Exposure Science Advisory Council (DESAC)

		Health Effects Division (7509P)

TO:		S. Jackson/B. Madden

		RIMUERB/RD (7505P)

Executive Summary

A chronic dietary risk assessment was conducted using the Dietary
Exposure Evaluation Model (DEEM-FCID(, Version 2.03), which uses food
consumption data from the USDA’s Continuing Surveys of Food Intakes by
Individuals (CSFII) from 1994-1996 and 1998.  The analysis was performed
to support the Section 3 requests to add uses on corn and soybeans. 
There is an existing use for chlorimuron ethyl on soybeans; however, the
registrant is requesting a use specifically on herbicide resistant
varieties.

Acute Dietary Exposure Results and Characterization

No toxicological endpoint attributable to a single dose of
chlorimuron-ethyl has been identified; therefore, an acute dietary
exposure assessment was not conducted.

Chronic Dietary Exposure Results and Characterization

The unrefined chronic dietary analysis for chlorimuron-ethyl is a
conservative estimate of dietary exposure with tolerance level residues
and 100% crop treated.  The risk estimate from chronic dietary exposure
to chlorimuron-ethyl as represented by the population adjusted dose
(PAD) is below HED’s level of concern for the U.S. population and all
population subgroups.  The exposure estimate of the general U.S.
population is <1% of the chronic PAD (cPAD).  The exposure estimate for
the most highly exposed subpopulation, All Infants (< 1 year old), is 1%
of the cPAD.

Cancer Dietary Exposure Results and Characterization

Chlorimuron-ethyl is classified as “not likely to be carcinogenic to
humans.”  A cancer dietary exposure analysis is not required.

Water Contribution	

EFED calculated the chronic surface water Tier I expected environmental
concentrations (EEC) for chlorimuron ethyl as 6.99 ppb. 

I.	Introduction

Dietary risk assessment incorporates both exposure and toxicity of a
given pesticide.  For acute and chronic assessments, the risk is
expressed as a percentage of a maximum acceptable dose (i.e., the dose
which 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 point of departure (POD, NOAEL, LOAEL,
e.g.) divided by the required uncertainty or safety factors.

For chronic exposures, HED is concerned when estimated dietary risk
exceeds 100% of the PAD.  HED is generally concerned when estimated
cancer risk exceeds one in one million. References which discuss chronic
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:      HYPERLINK
"http://www.epa.gov/fedrgstr/EPA-PEST/2000/July/Day-12/6061.pdf" 
http://www.epa.gov/fedrgstr/EPA-PEST/2000/July/Day-12/6061.pdf  ; or see
SOP 99.6 (20-AUG-1999).

The most recent dietary risk assessment for chlorimuron-ethyl was
conducted by HED as part of a human health risk assessment (D340291, A.
Parmar, 1/6/09).

II.	Food Residue and Percent Crop Treated Information

This chronic assessment was based on the assumption of tolerance-level
residues and 100 %CT for all commodities with existing and proposed
tolerances.  Tolerances have been established for residues of
chlorimuron-ethyl in/on peanuts and soybeans at 0.02 ppm and 0.05 ppm,
respectively [40 CFR §180.429].  ARIA is currently recommending
tolerances on the following raw agricultural commodities:

Corn, field, grain	0.01 ppm

Corn, field, forage	0.05 ppm

Corn, field, stover	2.0 ppm

Soybean, hay	1.8 ppm

Soybean, forage	0.45 ppm

Soybean, seed	0.05 ppm

Aspirated grain fractions	3.0 ppm 

DEEM default processing factors (Version 7.81) were used for cranberry
juice (1.1x) and peanut butter (1.89x).  Residues of chlorimuron ethyl
are not expected to concentrate in field corn or soybean processed
commodities.  At present, residues are not expected in livestock
commodities.

III.	Drinking Water Data

An updated drinking water assessment was conducted for the proposed uses
on the herbicide tolerant corn and soybeans (D358804, W. Shaughnessy,
6/15/09).  To account for exposure to residues in water under the most
conservative scenario, the value of 6.99 ppb (one-in-10-year mean) was
used in the dietary exposure assessment.  Water residues were
incorporated in the DEEM-FCID into the food categories “water, direct,
all sources” and “water, indirect, all sources.”   

EFED used the SCI-GROW (Screening Concentration In Ground Water) Model
to estimate the EEC of chlorimuron-ethyl residues in ground water.  The
EEC reported for chlorimuron-ethyl residues in ground water using
SCI-GROW is 6.99 ppb.  EFED used the FIRST (FQPA Index Reservoir
Screening Tool) Model to estimate the chronic EEC of chlorimuron-ethyl
residues in surface water.  EFED calculated the chronic surface water
Tier I estimated EEC’s for chlorimuron-ethyl as 5.02 ppb. 

The model and its description are available at the EPA internet site:  
HYPERLINK "http://www.epa.gov/oppefed1/models/water/" 
http://www.epa.gov/oppefed1/models/water/ .  

IV.		DEEM-FCID™ Program and Consumption Information

The chlorimuron-ethyl chronic dietary exposure assessment was conducted
using the Dietary Exposure Evaluation Model software with the Food
Commodity Intake Database DEEM-FCID™, Version 2.03, which incorporates
consumption data from USDA’s Continuing Surveys of Food Intakes by
Individuals (CSFII), 1994-1996 and 1998.  The 1994-96, 98 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 1994-96, 98
CSFII 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+
years old.

For chronic dietary exposure assessment, an estimate of the residue
level in each food or food-form (e.g., orange or orange juice) on the
food commodity residue list is multiplied by the average daily
consumption estimate for that food/food form to produce a residue intake
estimate.  The resulting residue intake estimate for each food/food form
is summed with the residue intake estimates for all other food/food
forms on the commodity residue list to arrive at the total average
estimated exposure.  Exposure is expressed in mg/kg body weight/day and
as a percent of the cPAD.  This procedure is performed for each
population subgroup.

V.		Toxicological Information

The Chlorimuron-ethyl Risk Assessment Team reviewed the most recent
endpoints, doses and uncertainty factors selected for risk assessment
and concluded that the toxicity endpoints and safety factors are
consistent with current policy.  No acute dietary toxicity endpoints
were identified; therefore, no risk assessments for acute exposure were
performed.  For chronic dietary exposure, a chronic toxicity study in
dogs was used to select the dose and endpoint for establishing the cRfD
of 0.09 mg/kg/day.  The endpoints and safety factors used for this risk
assessment are summarized in Table 1 below.

Table 1.  Toxicological Doses and Endpoints for Chlorimuron-ethyl. 

Exposure/

Scenario	Point of Departure	Uncertainty/

FQPA Safety Factors	RfD, PAD, Level of Concern for Risk Assessment	Study
and Toxicological Effects

Acute Dietary (General Population, including Infants and Children)	N/A

	N/A

	N/A

	The risk assessment was not conducted. No appropriate endpoint
identified.

Acute Dietary

(Females 13-49 years of age)	N/A

	N/A

	N/A

	The risk assessment was not conducted. No appropriate endpoint
identified.

Chronic Dietary (All Populations)	NOAEL = 9 mg/kg/day	UFA = 10X

UFH = 10X

FQPA SF = 1X	Chronic RfD = 0.09 mg/kg/day

cPAD = 0.09 mg/kg/day	Chronic toxicity – dogs

LOAEL = 50 mg/kg/day, based on mild anemia.

Cancer (oral, dermal, inhalation)	“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.  NOAEL = no observed adverse effect level. 
LOAEL = lowest observed adverse effect level.  UF = uncertainty factor. 
UFA = extrapolation from animal to human (interspecies).  UFH =
potential variation in sensitivity among members of the human population
(intraspecies).  FQPA SF = FQPA Safety Factor.  PAD = population
adjusted dose (a = acute, c = chronic).  RfD = reference dose.  N/A =
not applicable.

VI.		Results/Discussion 

As stated above, for chronic assessments, HED is concerned when dietary
risk exceeds 100% of the PAD.  The DEEM-FCID( analyses estimate the
dietary exposure of the general U.S. population and various population
subgroups.  The results reported in Table 2 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+
years old.  The dietary risk estimates in Table 2 are all below 100% of
the cPAD.  The most highly exposed subpopulation is All Infants (<1 year
old) at 1% of the cPAD.

This analysis is a highly conservative, unrefined dietary exposure
assessment.  Further refinement to the analysis could be made through
the use of anticipated residues, incorporation of percentages of crops
treated with chlorimuron-ethyl, and/or monitoring data that better
reflect residues at the time of consumption.  Since risk estimates are
well below HED’s level of concern, a more highly refined analysis is
not needed at this time.

Table 2.  Summary of Dietary Exposure and Risk for Chlorimuron-ethyl

Population Subgroup	Acute Dietary	Chronic Dietary	Cancer

	Dietary Exposure (mg/kg/day)	% aPAD*	Dietary Exposure

(mg/kg/day)	% cPAD*	Dietary Exposure

(mg/kg/day)	Risk

General U.S. Population	N/A	0.000188	<1	N/A

All Infants (< 1 year old)

0.000570	1

	Children 1-2 years old

0.000310	<1

	Children 3-5 years old

0.000300	<1

	Children 6-12 years old

0.000209	<1

	Youth 13-19 years old

0.000151	<1

	Adults 20-49 years old

0.000170	<1

	Adults 50+ years old

0.000168	<1

	Females 13-49 years old

0.000168	<1

	

VII.		Conclusions

This highly conservative, unrefined analysis demonstrates that the
requested uses for chlorimuron-ethyl will not result in chronic dietary
risk estimates that exceed HED’s level of concern for any of the
regulated population subgroups, including those comprised of infants and
children.  Chlorimuron-ethyl does not have acute or cancer dietary
endpoints; therefore, the results of the chronic analysis only are given
in the table above.

IX.	List of Attachments

Chronic Food And Drinking Water Residue Input file.

Chronic Results file.

Attachment 1: Chronic And Drinking Water Residue Input File

Filename: G:\chlorimuron\128901.R98                 Chemical:
Chlorimuron-ethyl

RfD(Chronic): .09 mg/kg bw/day  NOEL(Chronic): 9 mg/kg bw/day

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

Date created/last modified: 08-06-2009/14:11:29/8          Program ver.
2.03

Comment: CPAD = 0.09 mg/kg/day - Tolerance and 100%CT

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

  EPA    Crop                                   Def Res     Adj.Factors 
 Comment

  Code    Grp  Commodity Name                    (ppm)       #1    #2   

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

13020570 13B  Blueberry                          0.020000   1.000  1.000
 TOL

13020571 13B  Blueberry-babyfood                 0.020000   1.000  1.000
 TOL

15001200 15   Corn, field, flour                 0.010000   1.000  1.000
 

15001201 15   Corn, field, flour-babyfood        0.010000   1.000  1.000
 

15001210 15   Corn, field, meal                  0.010000   1.000  1.000
 

15001211 15   Corn, field, meal-babyfood         0.010000   1.000  1.000
 

15001220 15   Corn, field, bran                  0.010000   1.000  1.000
 

15001230 15   Corn, field, starch                0.010000   1.000  1.000
 

15001231 15   Corn, field, starch-babyfood       0.010000   1.000  1.000
 

15001240 15   Corn, field, syrup                 0.010000   1.000  1.000
 

15001241 15   Corn, field, syrup-babyfood        0.010000   1.000  1.000
 

15001250 15   Corn, field, oil                   0.010000   1.000  1.000
 

15001251 15   Corn, field, oil-babyfood          0.010000   1.000  1.000
 

95001300 O    Cranberry                          0.020000   1.000  1.000
 TOL

95001301 O    Cranberry-babyfood                 0.020000   1.000  1.000
 TOL

95001310 O    Cranberry, dried                   0.020000   1.000  1.000
 TOL

95001320 O    Cranberry, juice                   0.020000   1.100  1.000
 TOL

95001321 O    Cranberry, juice-babyfood          0.020000   1.100  1.000
 TOL

95002630 O    Peanut                             0.020000   1.000  1.000
 TOL

95002640 O    Peanut, butter                     0.020000   1.890  1.000
 TOL

95002650 O    Peanut, oil                        0.020000   1.000  1.000
 TOL

06003470 6    Soybean, seed                      0.050000   1.000  1.000
 TOL

06003480 6    Soybean, flour                     0.050000   1.000  1.000
 TOL

06003481 6    Soybean, flour-babyfood            0.050000   1.000  1.000
 TOL

06003490 6    Soybean, soy milk                  0.050000   1.000  1.000
 TOL

06003491 6    Soybean, soy milk-babyfood or in   0.050000   1.000  1.000
 TOL

06003500 6    Soybean, oil                       0.050000   1.000  1.000
 TOL

06003501 6    Soybean, oil-babyfood              0.050000   1.000  1.000
 TOL

86010000 O    Water, direct, all sources         0.006990   1.000  1.000
 EEC

86020000 O    Water, indirect, all sources       0.006990   1.000  1.000
 EEC

Attachment 2: Chronic Results File

U.S. Environmental Protection Agency                                
Ver. 2.00

DEEM-FCID Chronic analysis for CHLORIMURON-ETHYL                (1994-98
data)

Residue file name: G:\chlorimuron\128901.R98     Adjustment factor #2
NOT used.

Analysis Date 08-06-2009/14:45:10     Residue file dated:
08-06-2009/14:44:25/8

Reference dose (RfD, Chronic) = .09 mg/kg bw/day

COMMENT 1: CPAD = 0.09 mg/kg/day - Tolerance and 100%CT

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

                    Total exposure by population subgroup

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

                                                    Total Exposure

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

          Population                         mg/kg             Percent
of   

           Subgroup                       body wt/day             Rfd   
   

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

U.S. Population (total)                     0.000188                
0.2%

U.S. Population (spring season)             0.000187                
0.2%

U.S. Population (summer season)             0.000199                
0.2%

U.S. Population (autumn season)             0.000183                
0.2%

U.S. Population (winter season)             0.000183                
0.2%

Northeast region                            0.000172                
0.2%

Midwest region                              0.000192                
0.2%

Southern region                             0.000180                
0.2%

Western region                              0.000211                
0.2%

Hispanics                                   0.000210                
0.2%

Non-hispanic whites                         0.000183                
0.2%

Non-hispanic blacks                         0.000183                
0.2%

Non-hisp/non-white/non-black                0.000225                
0.3%

All infants (< 1 year)                      0.000570                
0.6%

Nursing infants                             0.000207                
0.2%

Non-nursing infants                         0.000707                
0.8%

Children 1-6  yrs                           0.000298                
0.3%

Children 7-12 yrs                           0.000199                
0.2%

Females 13-19 (not preg or nursing)         0.000142                
0.2%

Females 20+ (not preg or nursing)           0.000173                
0.2%

Females 13-50 yrs                           0.000176                
0.2%

Females 13+ (preg/not nursing)              0.000178                
0.2%

Females 13+ (nursing)                       0.000239                
0.3%

Males 13-19 yrs                             0.000159                
0.2%

Males 20+ yrs                               0.000164                
0.2%

Seniors 55+                                 0.000167                
0.2%

Children 1-2 yrs                            0.000310                
0.3%

Children 3-5 yrs                            0.000300                
0.3%

Children 6-12 yrs                           0.000209                
0.2%

Youth 13-19 yrs                             0.000151                
0.2%

Adults 20-49 yrs                            0.000170                
0.2%

Adults 50+ yrs                              0.000168                
0.2%

Females 13-49 yrs                           0.000168                
0.2%

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

Chlorimuron-ethyl	Dietary Exposure and Risk Assessment	DP Number: 365815


PC Code:  128901		

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