Impact/Purpose:

The overall objective of this research 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 provides the tools needed to collect and analyze food samples and to design and understand dietary measurements. The current specific objectives are:

1. to investigate more efficient methods for characterizing population exposures in dietary measurements studies (short-term subtask initiated in FY00; extramural);

2. to develop and improve analytical methods for contaminants in composite food samples collected in dietary measurements studies (long-term subtask; in-house);

3. to improve the model and food database system used in measurements studies for estimating dietary exposure and identifying sources (long-term subtask; extramural).

Description:

The research reported in this task description constitutes the MCEARD base dietary exposure research program and 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 is conducted as subtasks in the methods, measurements and modeling areas which are both short-term (3 yr or less) or longer-term in nature. Methods development consists of the infrastructure for an ongoing in-house program to develop and improve analytical methods for determination of environmental contaminants in dietary samples. Exposure measurements research consists of developing protocols and procedures to make dietary exposure measurements to support aggregate and cumulative measurements of exposure. Modeling-related research is a longer-term effort of refining and updating the existing Dietary Exposure Potential Model and food database system for predicting and interpreting measurements of exposure to environmental chemicals for various populations from total diets, food categories and/or food items, including drinking water. This research directly supports the requirements of FQPA by providing dietary exposure expertise for aggregate and cumulative exposure studies and assessments.

Record Details:

Record Type:PROJECT

Start Date:07/01/1998

Projected Completion Date:09/01/2004

Record ID: 29209

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Project Information:

Progress :Subtask 1: A contract was initiated in FY00 to begin work on alternative dietary monitoring protocols. Proposals from two potential contractors were received and work began in mid-FY01 to formulate alternative monitoring procedures for prioritization for further protocol development. A workshop is planned for early FY02.

Subtask 2: Comparison of state-of-the-art extraction techniques (ASE, SFE, microwave) used in the analysis of a chemically diverse group of pesticides was the topic of a presentation at the Florida Department of Agriculture Pesticide Residue Workshop, July 15-18, 2001, at St. Pete Beach FL. A manuscript based on this work has been submitted to the Journal of AOAC International. Development of a method for organophosphate pesticides in composite diets using automated pressurized fluid extraction with in-line clean-up was the topic of a presentation at the AOAC International Annual Meeting, September 9-13, 2001, at Kansas City, MO. A manuscript based on organophosphate pesticide method development work is anticipated.

Subtask 3: A new version of the Dietary Exposure Potential Model (DEPM) was made available in 2000 via the Internet, replacing the 1996 version. A presentation on the new version, entitled "Recent Enhancements to the Dietary Exposure Potential Model" by EA Julien, MR Berry, JR Tomerlin, MY Sert, KD Tucker, and DK Waylett, was made in early FY01 at the ISEA annual meeting. The newer version incorporates a facility to assign tap-water residues to food items to determine the impact of drinking water contaminants, such as disinfection by-products (DBPs), on total dietary exposure which was used to identify foods for methods development and analysis of DBPs.

Publications:

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 using a temperature programmable large volume injector with preseparation column. JAOAC International 84(3): 891-900.

Rosenblum, L., Garris, S.T. and Morgan, J.N. (2001). Comparison of five extraction methods for determining incurred and fortified pesticides in dietary composites. Submitted to JAOAC International.

Melnyk, L.J., Morgan, J.N., Fernando, R., Akinbo, O. and Pellizzari, E.D. (2001). Determination of metals in composite diet samples by ICP-MS. In preparation for submission to JAOAC International.

Presentations:

Rosenblum, L., Garris, S.T. and Morgan, J.N. Extraction of pesticides from fatty and non-fatty foods in composite dietary samples. Presented at the Florida Pesticide Residue Workshop, St. Pete Beach, FL, July 15-18, 2001.

Morgan, J.N., Hieber, T.E. and Kauffman, P.E. Automated pressurized fluid extraction with in-line clean-up for determination of pesticides in composite diets. Presented at the AOAC International Annual Meeting, Kansas City, MO, September 9-13, 2001.

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. Each subtask addressed 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 (LTG) as depicted by the Goal 3 (FQPA) Overview and Multi-Year Plan. Research conducted will improve 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 which are the LTGs of GPRA Goal 8.2 (Sound Science - Human Health) for NERL. Research to develop and improve measurement protocols for dietary exposure and analytical methods address three specific Goal 3 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. The dietary model and database system will develop scientifically sound approaches to provide improved exposure assessment and information for guidance on exposure evaluations and measurements. These activities are communicated to other NERL personnel through bi-weekly FQPA conference calls and planning meetings with HEASD; to the scientific community by publications and presentations at international meetings; and to OPPTS through program discussions with ALDs.

Clients :NERL multimedia field programs, OPPTS, OW

Project IDs:

ID Code :239

Project type :OMIS