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December 2000 Agenda

December 4, 2000

FIFRA SAP WEB SITE: http://www.epa.gov/scipoly/sap/
OPP Docket Telephone: (703) 305-5805


THURSDAY, DECEMBER 7, 2000
Sheraton Crystal City Hotel
1800 Jefferson Davis Highway
Arlington, VA 22202
(703) 486-1111

8:30 AM Introduction of Panel Members - Ronald Kendall, Ph.D. (FIFRA SAP Session Chair)

8:45 AM Administrative Procedures by Designated Federal Official - Ms. Olga Odiott

8:50 AM Welcome - Steven K. Galson, M.D., M.P.H. (Director, Office of Science Coordination and Policy, Office of Prevention, Pesticides and Toxic Substances, EPA)

8:55 AM Opening Remarks - Ms. Marcia Mulkey, (Director, Office of Pesticide Programs, Office of Prevention, Pesticides and Toxic Substances, EPA)

A CASE STUDY OF THE CUMULATIVE RISK OF 24 ORGANOPHOSPHATE PESTICIDES

9:00 AM Introduction and Overview - Elizabeth Doyle, Ph.D., Health Effects Division, Office of Pesticide Programs, EPA

SESSION I: CUMULATIVE RISK ASSESSMENT METHOD FOR DIETARY (FOOD) EXPOSURE

9:30 AM Dietary Protocols, Assumptions and Rationale - William Smith, Ph.D. and Mohsen Sahafeyan, Health Effects Division, Office of Pesticide Programs, EPA

10:15 AM Break

10:30 AM Public Comments

  • Chris Wilkinson, Ph.D., Wilkinson, LLC, on behalf of the Alliance for Reasonable Regulation of Insecticides (ARRI), FMC Corporation
  • Ray Layton, Ph.D., Du Pont Agricultural Products, on behalf of the American Crop Protection Association
  • 11:30 AM Panel Discussion

    Question 1: The OP case study uses PDP monitoring data only. Data for pesticide residues in foods from market basket surveys and FDA data are of similar quality and reflect the co-occurrence of multiple OPs. OPP considers it reasonable to combine these types of data in as much as they reflect similar data quality. However, these data sets combined reflect only a limited number of crops. How might data from field trials that are designed to reflect exaggerated use rates (maximum application rates and minimum pre-harvest intervals) be adjusted to reflect a more realistic estimate of pesticide residues to which the public is likely to be exposed?
    Discussants: Drs. Heeringa, McKone, and Ferson

    Question 2: The use of surrogate data and translation of residue data between crops with similar pest pressures and agronomic practices is common across commodities in single pesticide assessments. Under what practices can this approach be applied to multi-chemical assessments?
    Discussants: Drs. Reed, Whalon, and Portier

    12:30 PM LUNCH

    1:30 PM Panel Discussion (continued)

    Question 3: PDP and market basket surveys implicitly reflect usage of pesticides for the crops for which they are available and the co-occurrence of pesticides in those commodities. However, for commodities for which these types of data are not available, no direct measure of co-occurrence is available. OPP has considered assuming the independence of pesticide use weighted for the percent of the crop treated. What alternatives can the Panel suggest to estimate co-occurrence when direct measures are not available?
    Discussants: Drs. Portier, Macdonald, and Van Es

    SESSION II: CUMULATIVE RISK ASSESSMENT FOR RESIDENTIAL EXPOSURE

    2:00 PM Introduction, Surrogate Data Use, Assumptions, Use/Usage Data - Jeffrey Evans, Health Effects Division, Office of Pesticide Programs, EPA

    2:45 PM BREAK

    3:00 PM Public Comments

    Jack Zabik, Ph.D., Dow AgroScience, on behalf of the American Crop Protection Association

    4:00 PM Panel Discussion

    Question 4: Current methods for estimating residential exposures to single chemicals in residential settings rely upon the use of standard values derived from the literature or from studies submitted in support of pesticide registration. This approach was applied to the current cumulative case study, relying upon use instructions to determine the frequency, period of re-treatment, rate of pesticide application and dates of onset and discontinuance of use. No information is available for estimating likelihood of co-occurrence of pesticides in a residential setting. Is the adaptation of this single chemical assessment approach to a multi-chemical assessment reasonable? What aspects of this approach are appropriate? What aspects of this approach require development of better data?
    Discussants: Drs. Ferson, Portier, and Powell

    Question 5:Distributions of exposure parameters were introduced into the residential assessment in this case study, but only in the form of uniform distributions due to data limitations. OPP has little experience in the use of distributional analyses for residential exposures. What guidance can the Panel provide for determining the appropriateness of using point estimates, uniform distributions and fitted distributions?
    Discussants: Drs. Adgate, Heeringa, and McKone

    Question 6: Many data types are needed to improve the accuracy and precision of residential cumulative assessments. What types of data would be the most useful to further the ability to develop reasonable estimates of cumulative risk from residential use of pesticides?
    Discussants: Drs. Freeman, Kissel, and Needleman

    5:30 PM ADJOURNMENT


    FRIDAY, DECEMBER 8, 2000
    Sheraton Crystal City Hotel
    1800 Jefferson Davis Highway
    Arlington, VA 22202
    (703) 486-1111

    8:30 AM Introduction of Panel Members - Stephen Roberts, Ph.D. (FIFRA SAP Session Chair)

    8:45 AM Administrative Procedures by Designated Federal Official - Ms. Olga Odiott

    8:50 AM Welcome - Steven K. Galson, M.D. M.P.H. (Director, Office of Science Coordination and Policy, Office of Prevention, Pesticides and Toxic Substances, EPA)

    SESSION III: CUMULATIVE RISK ASSESSMENT FOR DRINKING WATER

    9:00 AM Introduction and Overview - David Miller, Health Effects Division, Office of Pesticide Programs, EPA

    9:10 AM Outputs from Regresion Model, Regional Breakouts from NAWQA - David Miller, Health Effects Division; Ronald Parker, Ph.D., and Nelson Thurman, Environmental Fate and Effects Division; Office of Pesticide Programs, EPA

    9:50 AM Public Comments

    Tom Gilding, on behalf of the American Crop Protection Association

    10:50 AM Break

    11:00 AM Panel Discussion

    Question 7: Current modeling procedures for estimating pesticide residues in drinking water rely upon a clear understanding of pesticide use patterns for agricultural and urban uses. In the absence of these data, it may be possible to back calculate use rates in urban environments from water concentration data and urban density data. This process was used in the current case study to estimate contribution from urban use. Is this approach a reasonable method for estimating urban use for the purposes of modeling water concentrations as a function of pesticide use? What alternative methods for estimating urban use of pesticides might OPP consider?
    Discussants: Drs. Tumeo, Van Es, and Powell

    Question 8: Assuming that the WARP model is adequately developed for use in risk assessments, is the approach taken in this example of a cumulative case study to incorporate exposure through drinking water appropriate? Can the Panel make any suggestions for improving the method by which drinking water is incorporated in cumulative assessments, given the limited availability of monitoring data?
    Discussants: Drs. Ferson, Heeringa, and Reed

    Question 9: In the case study, the 95th percentile upper bound prediction interval on the 95th percentile concentration estimate was used as the basis for year round estimates of pesticide exposure in drinking water. This approach was adopted because available estimates of concentrations of pesticides in drinking water are annualized, with no indication of seasonal variation. Is this approach a reasonable, health protective approach? What is the potential for this approach to underestimate short term exposure? If this approach produces an exceedance of essentially safe exposure levels, in what manner could a better estimate of exposure to pesticides in water be derived from existing data and modeling approaches?
    Discussants: Drs. Heeringa, Van Es, and Portier

    12:30 PM LUNCH

    SESSION IV: INTEGRATED CUMULATIVE RISK ASSESSMENT

    1:30 PM Presentation - David Hrdy, Health Effects Division, Office of Pesticide Programs, EPA

    2:30 PM BREAK

    2:45 PM Public Comments

    Robert Morris, Ph.D., FMC, on behalf of the American Crop Protection Association

    3:45 PM Panel Discussion

    Question 10: The case study demonstrates the combination of data for food, water and residential exposures that reflect differences in the quantity of available data. Does the Panel have any concerns about combining data for different exposure sources that differ in the extent to which they describe anticipated real world exposures?
    Discussants: Drs. Kissel, Portier, and Whalon

    Question 11: In the current integrated case study, the contribution of water relative to other sources of exposure is very small. This pattern was evident from the initial single source assessment that preceded the integrated cumulative assessment. This approach could be used as a form of sensitivity analysis to simplify of the overall assessment. Can the Panel recommend any considerations in determining the extent to which minor contributors to risk can be eliminated from an integrated cumulative risk assessment? Generically, can the Panel identify any major concerns or pitfalls in this approach?
    Discussants: Drs. Ferson, Adgate, and McConnell

    Question 12: The cumulative assessment in the case study was limited in geographic scale to the Piedmont areas of Virginia, North Carolina and South Carolina in an attempt to focus the scale of the assessment on an area of consistent seasonal variation and pest pressure. In this way, OPP hopes to develop an integrated assessment within which the water and residential uses are relative constant, making the risk assessment relevant for that particular area and other areas like it. Does the Panel find the geographic scale to be appropriately limited such that the results of the risk assessment are applicable across the entire area? What considerations should OPP apply to define the appropriate geographic scale for drinking water and residential cumulative risk assessments? Does the Panel see major pitfalls to this approach?
    Discussants: Drs. Van Es, Tumeo, and Powell

    Question 13: The data used in single chemical assessments often contains many sources of overestimation bias. However, because the cumulative risk assessment is developed from combining data from many sources and describing many pesticides, concerns for compounding conservatisms is greater than for single chemical assessments. In the current case study, OPP has taken the approach of depending to the extent possible on monitoring data which most closely approximates real world exposures and has applied the value of zero where no detectable residues were available for food residues. Are these conventions reasonable given the complexities and uncertainties inherent in combining many data sets to develop an integrated, multi-chemical, multi-pathway risk assessment?
    Discussants: Drs. Reed, Heeringa, and Freeman

    5:30 PM ADJOURNMENT

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    FIFRA SCIENTIFIC ADVISORY PANEL (SAP) OPEN MEETING DECEMBER 7 - 8, 2000


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