  SEQ CHAPTER \h \r 1 

     

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

                                                                        
                                                                        
                                    OFFICE 

OF CHEMICAL SAFETY

 AND POLLUTION PREVENTION

MEMORANDUM

DATE:  	1-December-2010

SUBJECT:	Mefenoxam.  Second Amendment to Human Health Risk Assessment
Document DP# D369043.  

  

PC Code: 113502	DP Barcodes: D369043, D384459

Decision No.: 416985	Registration Nos.: 100-801, 100-804, 100-1202 

Petition No.: 9E7591	Regulatory Actions: Section 3/Amended Section 3
Registration

Case No.: NA	Risk Assessment Type: Single Chemical/Aggregate

TXR No.: NA	CAS No.: 70630-17-0

MRID No.: NA	40 CFR: §180.546 (Mefenoxam)

		              									

FROM:	Meheret Negussie, Chemist, Risk Assessor

		Nancy Dodd, Chemist

		Nancy Tsaur, Chemist, ORE Assessor

		Whang Phang, Toxicologist

		Risk Assessment Branch III

		Health Effects Division (HED) (7509P)	  SEQ CHAPTER \h \r 1 

		

THROUGH:	Paula Deschamp, Branch Chief	

		Risk Assessment Branch III

		Health Effects Division (7509P)

		

TO:		Barbara Madden/Laura Nollen, RM #5

		Registration Division (RD) (7505P)  SEQ CHAPTER \h \r 1   SEQ CHAPTER
\h \r 1 

This memorandum amends the Human Health Risk Assessment Document (DP#
D369043, M. Negussie, 07/28/10), to correct percent crop treated (PCT)
assumptions for the proposed uses on snap bean, caneberry (raspberry)
and spinach; correct PCT input for pumpkin; and revise dietary inputs to
the aggregate exposure (short-term and long-term) according to the
revised dietary assessment; and incorporates additional clarification
regarding residential exposure pathways.

 

Percent Crop Treated Data used for the Chronic Assessment:  

1. Mefenoxam average %CT values are all higher than metalaxyl average
%CT values, so the mefenoxam SLUA (5/5/2009) was incorporated into the
dietary assessment. 

Table 5.3.4.  Percent Crop Treated Data for Mefenoxam.*

Commodity	Average Percent Crop Treated Data	Commodity	Average Percent
Crop Treated Data

Almonds	<1	Lemons	5

Apples	<1	Lettuce	10

Artichokes	5	Onions	30

Asparagus	10	Oranges	5

Avocados	<2.5	Peaches	<1

Beans, green	10	Peanuts	<1

Blueberries	<1	Peas, green	<2.5

Broccoli	10	Peppers	15

Cabbage	10	Potatoes	20

Caneberries	15	Pumpkins	<5

Cantaloupes	10	Raspberries	20

Carrots	35	Rice	<1

Cauliflower	5	Soybeans	10

Celery	5	Spinach	55

Cherries	<1	Squash	10

Cotton	5	Strawberries	10

Cucumbers	10	Sugar beets	<1

Dry Beans/Peas	<1	Sweet corn	<1

Garlic	15	Tangerines	10

Grapefruit	5	Tomatoes	15

Grapes	<1	Walnuts	<1

Honeydew	5	Watermelons	15

* Mefenoxam Screening Level Usage Analysis, 05/05/2009.

2. For the proposed uses on snap bean, caneberry (including raspberry)
and spinach, the dietary risk assessment was re-evaluated assuming 100%
CT.  Estimated average PCT for mefenoxam was used for onion, garlic and
blueberry.  

3. The dietary exposure was re-evaluated using 5% CT for pumpkin.

4. Table 5.3.4 as shown above reflects the corrected average % CT (5%)
for pumpkin. 

Results of the revised dietary exposure assessment are summarized below
in Table 5.3.

Table 5.3.  Summary of Dietary (Food and Drinking Water) Exposure and
Risk for Mefenoxam/Metalaxyl.1

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	NA	0.019553	26	NA	NA

All Infants (< 1 year old)

0.022953	31



Children 1-2 years old

0.044380	60



Children 3-5 years old

0.041879	57



Children 6-12 years old

0.028401	38



Youth 13-19 years old

0.018250	25



Adults 20-49 years old

0.016353	22



Adults 50+ years old

0.014734	20



Females 13-49 years old

0.015493	21



 1	The population subgroup with the highest estimated chronic dietary
(food + drinking water) exposure and risk is indicated by bold text.

Short-Term and Intermediate-Term Aggregate Risk: TC \l2 "7.3
Intermediate-Term Aggregate Risk 

The short-term and intermediate-term aggregate risk calculations were
revised to reflect the modified dietary exposure inputs and are
summarized in Tables 7.2 and 7.3 below. The slight increase in dietary
exposure had minimal impact on the overall aggregate risk estimates. In
addition, the intermediate-term aggregate risk calculation was revised
to reflect the appropriate intermediate-term NOAEL of 7.4 mg/kg/day. The
short-term aggregate risk assessment for the general population
incorporates adult handler inhalation exposures and dietary (food +
water exposures); risk from dermal exposure is not included because no
dermal hazard was identified. Although a point of departure from an oral
study was used to assess residential handler inhalation risks for
mefenoxam, HED does not believe this aggregate assessment is
under-protective of adult handlers.  MOEs calculated for residential
handlers were all >150,000, thus providing an ample margin of safety to
account for any uncertainties in route-to-route extrapolation. 

Table 7.2.  Short-Term Aggregate Risk Calculations.		



Population	Short-Term Scenario

	NOAEL

mg/kg/day	LOC1	Average Food

& Water

Exposure

mg/kg/day	Residential Exposure2

mg/kg/day	Aggregate MOE

(food and

residential)3

General U.S. Population	50	100	0.019553	0.00033	2500

Children 1-2 years	50	100	0.044380	0.01233	880

Children 3-5 years	50	100	0.041879	0.01233	920

1	100X = 10X interspecies and 10X intraspecies uncertainty factors.

2	Residential Exposure = [Oral exposure + Inhalation Exposure]. 
Mefenoxam. Human Health Risk Assessment for Proposed Uses on Succulent
Shelled Beans and Turnip Greens. Myron Ottley, 05/31/2007.

3	Aggregate MOE = NOAEL / (Avg Food & Water Exposure + Residential
Exposure).

Table 7.3.  Intermediate-Term Aggregate Risk Calculations.



Population	Intermediate-Term Scenario

	NOAEL

mg/kg/day	LOC1	Average Food & Water

Exposure

mg/kg/day	Residential Exposure2

mg/kg/day	Aggregate MOE

(food and

residential)3

Children 1-2 years	7.4	100	0.044380	0.006933	140

Children 3-5 years	7.4	100	0.041879	0.006933	150

1	100X = 10X interspecies and 10X intraspecies uncertainty factors.

2	Residential Exposure = [Oral exposure + Inhalation Exposure]. 
Mefenoxam. Human Health Risk Assessment for Proposed Uses on Succulent
Shelled Beans and Turnip Greens. Myron Ottley, 05/31/2007.

3	Aggregate MOE = NOAEL / (Avg Food & Water Exposure + Residential
Exposure).

Conclusions:

Results of the chronic dietary assessment indicate that the general U.S.
population and all other population subgroups have exposure and risk
estimates below HED’s level of concern (LOC).  The use of 100% CT for
proposed commodities (green bean, spinach, and caneberry) resulted in a
marginal increase to the dietary exposure and risk.  The chronic dietary
exposure estimates are 26% of the cPAD for the general U.S. population
and 60% of the cPAD for the highest exposed population subgroup,
children 1-2 years of age. 

Since the short-term and intermediate-term aggregate MOEs are all
greater than 100, risk estimates do not exceed HED’s LOC.  

All other information contained in the 2010 human health risk assessment
document (DP# D369043) remains unchanged. 

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