Impact/Purpose:

The overall objective of the MCEARD dietary exposure research program is to support NERL's human exposure measurement and exposure modeling efforts by reducing the amount of uncertainty in the dietary measurements critically needed for improved risk assessment. Specifically, the research conducted under this task provides the tools needed to analyze composite food and beverage samples for the presence of pesticides, starting with pyrethroids. The specific objectives of this task are to develop and improve analytical methods for contaminants in composite food and beverage samples collected in dietary measurements studies and to analyze small numbers of samples in support of these studies. A series of analytical methods and/or journal articles are anticipated through FY07.

Description:

The Microbiological and Chemical Exposure Assessment Research Division's (MCEARD) dietary exposure research program is conducted to complement the NERL aggregate and cumulative exposure program. Its purpose is to reduce the level of uncertainty in exposure assessment by improving NERL's ability to evaluate dietary exposure relative to other pathways. Research focuses on improving procedures to measure and understand dietary exposure in NERL field studies. The research conducted under this task constitutes the analytical method development component of the MCEARD dietary exposure research program. The analytical method development component consists of the infrastructure for an ongoing in-house and extramural program to develop and improve analytical methods for determination of environmental contaminants in dietary samples as well as maintaining a capacity to perform routine sample analysis on small numbers of samples using methods developed under the program. This research directly supports the requirements of Food Quality Protection Act (FQPA) by providing dietary exposure expertise for aggregate and cumulative exposure studies and assessments.

Record Details:

Record Type:PROJECT

Start Date:10/01/2002

Projected Completion Date:09/01/2007

OMB Category:Other

Record ID: 56098

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Project Information:

Progress :Two methods developed under this task were used in the analysis of food and beverage samples collected in a children's study in California's Salinas Valley. These analyses were completed in FY04 using a method for organophosphorus pesticides and a multiclass, multiresidue method. Results of this study, including results of dietary analyses conducted under this task, were presented at the 14th Annual Conference of the International Society of Exposure Analysis, October 17 - 21, 2004, Philadelphia, PA. The paper was entitled "Quantitative Pesticide Exposure Assessment of Children Living in an Agricultural Community" by Asa Bradman et al. (Morgan is co-author).

Work on the development of a method for synthetic pyrethroids in foods and beverages was initiated. Preliminary results have been presented at the Florida Pesticide Residue Workshop (see TIMS report below). Accelerated solvent extraction followed by alumina and diatomaceous earth cleanup steps and GC/MS analysis have shown good recoveries with detection limits for most analytes in the 10-20 ppb range.

Two methods developed under this task were included in a compilation of methods for characterizing children's exposures to pesticides and other environmental contaminants. These methods were also included in a presentation entitled "Analytical Methods for the Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) Study," by Myriam Medina-Vera et al. (Morgan is co-author) presented at the 56th Southeast Regional Meeting of the American Chemical Society, November 10 - 13, 2004, Research Triangle Park, NC.

RELATED PUBLICATION

The following publication is associated with a previously completed NERL research task. It is included here because it forms the basis for one of the methods included in the compilation of methods for characterizing children's exposures to pesticides and other environmental contaminants:

Rosenblum, L., Hieber, T. and Morgan, J.N. 2001. Determination of pesticides in composite dietary samples by gas chromatography/mass spectrometry in the selected ion monitoring mode by using a temperature-programmable large volume injector with preseparation column. JAOAC International 84:891-900.

Relevance :This research directly supports USEPA's multimedia approach to human exposure and risk assessment and the goals of FQPA, which requires aggregate and cumulative exposure assessments for pesticides, and specifically, assessments of children's exposures. Research conducted under this task will provide information fundamental to an improved understanding of dietary exposure which supports NERL's multimedia human exposure program and long-term goal FQ-1. Research conducted will improve the Office of Prevention, Pesticides, and Toxic Substances' (OPPTS) and NERL's understanding of dietary exposure by reducing the uncertainties and reliance on current default assumptions which, in turn, will allow these clients to regulate and conduct accurate risk assessments. Research conducted under this task also provides important input to the guidance and guidelines documents to assess aggregate and cumulative exposures. Research to develop and improve measurement protocols for dietary exposure and analytical methods address three objectives by providing: consistent and scientifically sound methods and approaches for measuring exposure; major factors that contribute to variability in exposure; and, support for measurement studies to determine distributions of aggregate and cumulative exposures for infants and children. Applied methods development that provides quality assured data for environmental assessments consistent with methods for other exposure media supports NERL's integrated multimedia approach to risk assessment. These activities are communicated to other NERL personnel through biweekly FQPA conference calls and planning meetings with NERL's Human Exposure and Atmospheric Sciences Division; to the scientific community by publications and presentations at international meetings; and to OPPTS through program discussions with Assistant Laboratory Directors.

Clients :NERL multimedia field programs, Office of Prevention, Pesticides, and Toxic Substances (OPPTS)

Project IDs:

ID Code :15037

Project type :OMIS