Impact/Purpose:

The overall objectives of the task include several components: (1) develop immunochemical methods for compounds difficult to analyze by conventional methodologies; (2) tailor immunochemical methods to support specific human exposure assessment studies; (3) team immunochemical sample preparations with instrumental analysis such as mass spectrometry for in-depth sample characterization; (4) provide methods to support NERL's human exposure and environmental monitoring efforts; (5) provide analytical methods that improve risk assessments by reducing the amount of uncertainity in environmental measurements; (6) provide multimedia analytical methods to support an integrated multimedia approach to assess and characterize risk to human health and the environment; (7) provide sponsorship of annual immunochemistry research meetings as a forum for stimulating interest and discussion on current or emerging bioanalytical methods; (8) develop and incorporate rapid, cost-effective laboratory and field portable immunochemical techniques such as enzyme-linked immunosorbent assay (ELISA) methods into monitoring studies and human exposure field surveys to delineate sub-populations of "highly exposed" individuals for detailed follow-up studies.

Specific method needs have been identified through consultations with client office personnel. This Task strives to fulfill those needs as appropriate. In particular, methods for pyrethroids, e.g., permethrin, cypermethrin, and deltamethrin are being developed and evaluated. Efficient sample preparations are under development for exposure samples using pressurized liquid extraction. Confirmation will be achieved using high performance liquid chromatography (HPLC). A rapid immunoassay approach for the analysis of 2,4-D in urine will be completed and a SOP and report written. Immunoaffinity chromatography sample preparations for the pyrethroids will be developed. Work will continue on the application of antibody replacements such as molecularly imprinted polymers. Additional candidate analytes will be identified for a tiered approach and to guide development of the next Task. Flexibility will be maintained to address methods and measurement issues as they arise during the task period which ends in FY06. The objective of the Task is to develop bioanalytical methods to support exposure monitoring studies during the task period.

Description:

More data are needed to accurately determine the impact of pesticides on human health, especially for infants and young children. One of the ways to reduce uncertainties in the assessment of human exposure to pesticides, and other environmental contaminants, is through extensive environmental monitoring and dietary exposure studies. An alternate approach is to monitor distinctive urinary or serum biomarkers of exposure. A significant limitation to either approach, however, is that sampling and laboratory analysis of multi-media samples (e.g., air, water, soil, dust, body fluids, and food) are slow and expensive, limiting the number of samples that can be analyzed within time and budget constraints. Faster and more cost-effective field screening and monitoring methods can increase the amount of information available concerning the location and concentration of target analytes that might impact human health and the environment. The primary goal of this task is to develop fast, reliable, and cost-effective immunochemical and other bioanalytical methods for measuring human exposures to pesticides and other contaminants. This task specifically addresses the development of immunochemical methods to assess nonoccupational low-level pesticide exposures.

Cooperation and collaboration with EPA Program Offices and other clients are undertaken to fulfill the project objectives and goals of the Task. To facilitate communications among researchers and clients, a yearly Immunochemistry Summit meeting is held. Prioritization of projects is based on the needs expressed by Client Program Offices, NERL measurement studies, the applicability of individual immunochemical methods, available reagents and technologies, and other essential parameters such as data quality objectives. Methods to determine dislodgeable residues of chlorpyrifos from vegetation, chlorpyrifos in foods and dust, and TCP in urine and dust have been developed and applied to samples from exposure studies. Methods for determining pyrethroids and 2,4-D in samples from toxicologic and exposure studies are under development and nearing completion. As appropriate, samples from measurement Tasks such as #3913, #3943 and #15565 are sought for method evaluation and to determine method applicability to human exposure assessment monitoring. This Task will be completed in FY06 and replaced with another methods task.

Record Details:

Record Type:PROJECT

Start Date:10/01/1999

Projected Completion Date:09/01/2006

OMB Category:Other

Record ID: 29218

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Project Information:

Progress :The progress to date for this project can be summarized as follows: Immunochemical measurement methods have been developed for compounds of significance for clients and stakeholders (e.g., chlorpyrifos and the related biomarker TCP; 2,4-D and various pyrethroids). Matrices addressed include food and urine from exposure studies, soil, dust and dislodgeable foliar residues. Efficient and rapid extraction procedures such as accelerated solvent extraction and supercritical fluid extraction have been coupled with immunoassay determination. Standard Operating Procedures (SOPs) for each method have been written. Immunologic reagents have been synthesized and developed or obtained through collaborations. Task activities and results are communicated through presentations, both inhouse and at national/international meetings, peer reviewed publications and direct communications with client office personnel. The Immunochemistry Summit Meetings have been held as special symposia within the American Chemical Society national meetings. Direct contact provides feedback and guidance for establishing research objectives. This Task recently contributed to APM #226 a collection of analytical method SOPs. Some of the progress to date is listed below and is indicative of the approach taken to fulfill Task objectives.

-Completion of APM #217, Develop and Recommend Immunochemistry-based Methods for Measuring Pesticide Residues in Foods.

-Identification of target analytes based upon NERL and Client Program Office needs for immunochemical methods development. Target analytes include parent, metabolite and environmental degradation product (dependent upon goals of the particular monitoring study). Analytes identified to date include: chlorpyrifos and its major metabolite 3,5,6-trichloro-2-pyridinol (TCP); 2,4-D; permethrin; esfenvalerate; pyrethroid urinary biomarkers; class identification systems for select organophosphorus pesticides; and various triazines and carbamates.

-Databases such as TASS and DRESS have been used to help identify target analytes, matrices, and available analytical methods for dietary exposure studies. This information, in tandem with the dietary model (DEPM), was used to design the appropriate immunochemical methods for food matrices.

-An immunoassay to detect the TCP metabolite of chlorpyrifos in urine was developed and compared with GC/MS. Several hundred samples from various nonoccupational exposure studies were analyzed by the ELISA.

- SOPs were written for determining TCP in urine and chlorpyrifos in dust by immunoassay.

- A journal article describing many of the activities of this Task was published in the Journal of the Association of Official Analytical Chemists.

-Two issues of Analytical Chemica Acta have been dedicated to the Immunochemistry Summit Meetings



Relevance :Particular attention is given to methods development to determine nonoccupational exposures of children, an implementation requirement of the Food Quality Protection Act (FQPA). The task supports the NERL research framework that the most accurate exposure data are developed from direct measures of individual exposures, activity pattern data, and biological indicators of exposure. To assess pesticide exposures of children, it is necessary to either measure the contaminant at the interface between children and their environment, or measure the actual compound or metabolite(s) in body fluids. Under this task, immunochemical methods are being developed to measure contaminants in both indoor and outdoor environments, as well as to determine urinary biomarkers of exposure. This task provides direct support to the Children's Total Exposure to Pesticides and Persistent Pollutants (CTEPP) project, and the Agricultural Health Study. Cost-effective analytical methods provide support to in-depth monitoring studies to reduce uncertainities in exposure assessment measurements by allowing a larger sample capacity. Products from this Task also support cumulative and aggregate exposure monitoring studies to estimate exposures to pesticides. Techniques and methods developed and demonstrated under this Task are expected to be integrated into measurement studies. Information on research products will be disseminated to clients through presentations, publications and direct communications.



Clients :OPP; OPPTS; OSCP; Office of Children's Health Protection; OW; EPA Regions ; NCEA, NHEERL scientific community, pesticide industry

Project IDs:

ID Code :3904

Project type :OMIS