Quiero saber acerca de...

khammond on DSKJM1Z7X2PROD with RULES

48328

Federal Register / Vol. 86, No. 165 / Monday, August 30, 2021 / Rules and Regulations
DEEMFCID version 3.16/Calendex to estimate exposure by combining data on human consumption amounts with residue values in food commodities.
The model incorporates 20032008
consumption data from USDAs NHANES/WWEIA. The data are based on the reported consumption of more than 20,000 individuals over two nonconsecutive survey days. Foods as consumed e.g., apple pie are linked to EPA-defined food commodities e.g., apples, peeled fruitcooked; fresh or N/
S Not Specified; baked; or wheat flourcooked; fresh or N/S, baked using publicly available recipe translation files developed jointly by USDA Agricultural Research Service ARS and EPA. For chronic exposure assessment or in the case of chlorpyrifos, for steady-state exposure assessment, consumption data are averaged for the entire U.S. population and within population subgroups;
however, for acute exposure assessment, consumption data are retained as individual consumption events. Using this consumption information and residue data, the exposure estimates are calculated for the general U.S.
population and specific subgroups based on age, sex, ethnicity, and region.
For chlorpyrifos, EPA determined that acute and steady-state exposure durations were relevant for assessing risk from food consumption. EPA
calculates potential risk by using probabilistic techniques to combine distributions of potential exposures in sentinel populations. The resulting probabilistic assessments present a range of dietary exposure/risk estimates.
Because probabilistic assessments generally present a realistic range of residue values to which the population may be exposed, EPAs starting point for estimating exposure and risk for such assessments is the 99.9th percentile of the population under evaluation. When using a probabilistic method of estimating acute dietary exposure, EPA
typically assumes that, when the 99.9th percentile of acute exposure is equal to or less than the aPAD, the level of concern for acute risk has not been exceeded. By contrast, where the analysis indicates that estimated exposure at the 99.9th percentile exceeds the aPAD, EPA would generally conduct one or more sensitivity analyses to determine the extent to which the estimated exposures at the high-end percentiles may be affected by unusually high food consumption or residue values. The same assumptions apply to estimates for steady state dietary exposure and the ssPAD. To the extent that one or a few values seem to drive the exposure estimates at the
VerDate Sep<11>2014

16:13 Aug 27, 2021

Jkt 253001

high-end of exposure, EPA would consider whether these values are reasonable and should be used as the primary basis for regulatory decision making Ref. 20.
2. Estimating Chlorpyrifos Exposures in Food The residue of concern, for tolerance expression and risk assessment, in plants food and feed and livestock commodities is the parent compound chlorpyrifos. EPA has determined that the metabolite chlorpyrifos oxon is not a residue of concern in food or feed, based on available field trial data and metabolism studies that indicate that the oxon is not present in the edible portions of the crops. In addition, the chlorpyrifos oxon is not found on samples in the USDA PDP monitoring data. Furthermore, the oxon metabolite was not found in milk or livestock tissues Ref. 9 at 33.
Acute and steady-state dietary food only exposure analyses for chlorpyrifos were conducted using the DEEMFCID
version 3.16/Calendex software Ref.
23. These analyses were performed for the purpose of obtaining food exposure values for comparison to the chlorpyrifos doses predicted by the PBPKPD model to cause RBC AChE
Inhibition. The acute and steady-state dietary food only exposure analyses do not include drinking water exposures, which were assessed separately, see Unit VII.B.2.
Both the acute and steady state dietary exposure analyses are highly refined. The large majority of food residues used were based upon PDP
monitoring data except in a few instances where no appropriate PDP
data were available. In those cases, field trial data or tolerance level residues were assumed. EPA also used food processing factors from submitted studies as appropriate. In addition, EPAs acute and steady state dietary exposure assessments used percent crop treated PCT information. Ref. 23
The chlorpyrifos acute dietary exposure analysis was conducted using the DEEMFCID, version 3.16, which incorporates 20032008 survey consumption data from USDAs NHANES/WWEIA. The acute risk estimates were presented for the sentinel populations for infants less than 1 yr old; children 12 years old;
youths 612 years old; and adults females 1349 years old. The assessment of these index lifestages is protective of other population subgroups.
The chlorpyrifos steady-state dietary exposure analysis was conducted using the Calendex component of DEEMFCID

PO 00000

Frm 00034

Fmt 4700

Sfmt 4700

with 20032008 survey consumption data from USDAs NHANES/WWEIA.
Calendex provides a focus detailed profile of potential exposures to individuals across a calendar year. A
calendar-based approach provides the ability to estimate daily exposures from multiple sources over time to an individual and is in keeping with two key tenets of aggregate risk assessment:
1 That exposures when aggregated are internally consistent and realistic; and 2 that appropriate temporal and geographic linkages or correlations/
associations between exposure scenarios are maintained.
The chlorpyrifos steady state assessment considers the potential risk from a 21-day exposure duration using a 3-week rolling average sliding by day across the year. For this assessment, the same food residue values used in the acute assessment were used for the 21day duration. In the Calendex software, one diary for each individual in the WWEIA is selected to be paired with a randomly selected set of residue values for each food consumed. The steadystate analysis calculated exposures for the sentinel populations for infants less than 1 year old; children 12 years old; youths 612 years old; and adults females 1349 years old. The assessment of these index lifestages is protective of other population subgroups.
B. Exposure From Drinking Water 1. General Approach for Assessing Exposure From Drinking Water a. Modeling and Monitoring Data Monitoring and modeling are both important tools for estimating pesticide concentrations in water and can provide different types of information.
Monitoring data can provide estimates of pesticide concentrations in water that are representative of the specific agricultural or residential pesticide practices in specific locations, under the environmental conditions associated with a sampling design i.e., the locations of sampling, the times of the year samples were taken, and the frequency by which samples were collected. Although monitoring data can provide a direct measure of the concentration of a pesticide in water, it does not always provide a reliable basis for estimating spatial and temporal variability in exposures because sampling may not occur in areas with the highest pesticide use, and/or when the pesticides are being used and/or at an appropriate sampling frequency to detect high concentrations of a pesticide that occur over the period of a day to several days.

E:FRFM30AUR1.SGM

30AUR1