Impact/Purpose:

The goal of this task is to contribute to a better understanding of human exposure to pesticides, especially for small children by developing methods to characterize sources and pathways in and around the residential environment. We will support the science behind FQPA and assist the Office of Pesticide Programs (OPP) in the development of guidelines for the assessment of residential exposure to pesticides. Specific research objectives include: (i) to evaluate and develop methods for measuring pesticides in air using passive/diffusive samplers. Assess and refine devices for the collection of surface transferable pesticide residues and to establish transfer efficiencies; (ii) to develop and apply analytical methods for new and emerging pesticides using both gas and liquid chromatographic methods in support of the National Exposure Research Laboratory's (NERL) Human Exposure Measurement Project; and, (iii) to conduct pilot studies investigating chiral chromatographic methods.

Description:

Note: this task is schedule to end September 2003. Two tasks will take its place: method development for emerging pesticides including chiral chemistry applications, and in-house laboratory operations. Field sampling methods are covered under a new task proposed this year.

This research involves the development, validation, and application of methods that can be used for the estimation of human exposure to pesticides, with emphasis on infants and toddlers. Methods that can be used to accurately measure pesticides in environmental media that can be used to estimate respiratory, dermal and nondietary oral exposures, as well as transport mechanisms leading to exposure, are being developed. Methods research under this task includes the measurement of pesticides in air over two-week or longer periods by means of passive/diffusive sampling devices, the measurement of transferable residues using established and novel collection tools to determine transfer efficiencies from common residential surfaces, the development of analytical methodologies for current and new pesticides using gas and liquid chromatographic techniques and finally the evaluation of methods for measuring chiral pesticides in residential exposure media. These measurement methods are needed for a better understanding of children's exposures and to support the requirements of the Food Quality Protection Act (FQPA). In addition, a better understanding is being sought of the transport routes of pesticides within residences and from the outdoors to the indoor environment.

Record Details:

Record Type:PROJECT

Start Date:11/01/2001

Completion Date:09/01/2003

Record ID: 56192

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Project Information:

Progress :Residential samples were collected to be analyzed by LC/MS/MS (liquid chromatography/mass spectronmetry). Some report delays for FY 02 are due to the shift of resources (contract hours) to the World Trade Center sample collection and analysis.

There has been significant work by NERL researchers in related areas of methods research. The in-house laboratory operation has been completed and personnel assigned and hired. Two Senior Environmental Employment Program (SEEP) technical employees started work November 4, 2002 to aid in the lab analysis. Work was performed to evaluate methods for collecting surface pesticide residues. Particle fate and transport studies designed to determine the potential for residential exposure to pesticides associated with house dust and tracked-in soil were completed and two journal articles were submitted. Three methods for determining dislodgeable pesticide residues from floors have been subjected to round-robin testing and the results published. A hand wipe procedure that is very acceptable to small children has been developed, field-tested, and published. Human volunteers have been used to measure dislodgeable residues by pressing their hands on both untreated and freshly-treated carpets; three research reports have, a book chapter, and a journal article have resulted. Research has been completed and an EPA report published on the evaluation of saliva surrogates that will provide a better means of determining the potential for residues picked up on the skin to be transferred to the mouth and ingested. A conference paper was published in June, 2000 and a journal article was subsequently submitted on the fate and transport of pesticides applied simultaneously by crack and crevice and perimeter treatments.

Work under a cooperative agreement with Battelle to study the track-in and indoor redistribution of lawn-applied herbicides was completed. Twelve homes, including homes in which homeowners applied pesticides themselves and those who employed commercial applicators, were examined to assess the relative importance of air, house dust, and dermal contact as routes of exposure for small children. A final report, and several journal articles and conference paper have resulted.

Research on passive air sampling methods was initiated under an on-site contract to ManTech Environmental Technology, Inc. A study design was developed and implemented which has allowed for the testing of passive/diffusive air samplers in a controlled setting . Currently several passive/diffusive air samplers have been evaluated and further evaluations are planned. Findings have resulted in presentations at several national and international conferences.

Studies to develop methods to analyze new and upcoming pesticides in support of the Exposure Measurements and Analysis Branch (EMAB) are in their infancy. A state-of -the-art LC/MS/MS instrument has been purchased and will be evaluated upon arrival for the analysis of samples collected from pilot scale residential studies. An in-house analytical capability for pesticide analysis is being developed by the Methods Development and Application Branch (MDAB) to support EMAB field studies. A GC/MS (gas chromatograph/mass spectrometer) is currently under evaluation with plans to provide additional analytical support through contract with ManTech Environmental Technology, Inc. A post-doctoral position, whose FTE's will be linked to this effort, has recently been filled. Planning by MDAB has intensified to develop an in-house capability for the analysis of pesticide residues in support of EMAB's field studies.

A study of chiral pesticides in human breast milk was initiated using sample extracts acquired from the National Institute of Environmental Health Sciences (NIEHS). The samples were found to be too old to provide meaningful results.

Relevance :Work to be performed under this task will directly support the NERL human exposure measurements program by development and validation of sampling and analysis methods for current use residential pesticides and new and emerging pesticides. The work directly links to Task 7040, Human Exposure Measurements - Children's Focus in Support of FQPA - Field Verification Studies. Under this task sampling methods that are planned for use in the field verification studies will be evaluated, refined, and validated. Their performance will be documented prior to use in the field measurement studies. Multi-residue analytical methods will be developed and validated that will be used to analyze multi-media samples in ongoing field studies that are conducted in the Human Exposure and Analysis Branch. The research completed in this task will allow NERL to determine if chirality infers enantomeric selectivity when partitioning into human adipose tissues and analyze environmental samples from Children's Total Exposure to Persistent Pesticides (CTEPP) study for chiral pesticides.

The results of studies performed under this task will contribute to the goals of the Office of Pesticide Programs by providing data that can be used to upgrade the risk assessment procedures pertaining to cumulative and aggregate risk. The work conducted under this task will provide information to meet GPRA Goals 3 and 8. This task will contribute to these goals by providing methods needed to collect exposure concentration data and exposure factor data on children's non-occupational exposures to pesticides. The work under this task will provide information to meet GPRA Goal #3, Safe Food, Subobjective 3.2.4 - By 2005, provide problem-driven research results to support the new FQPA regulatory standard of "a reasonable certainty of no harm" for pesticides used on food. It responds to the FQPA provision that requires consideration of children's exposure to pesticide residues from all sources, including foods, drinking water, and pesticide applications in homes, schools, day-care centers, and other microenvironments. The distributional data collected in the field verification studies using methods developed in this task will reduce the reliance on default human exposure assessment assumptions and provide inputs for multipathway models of children's exposure to pesticides. In addition, outputs of this task are intimately linked with the core human exposure research conducted under GPRA Goal 8 which integrates the advances in exposure science from all of the NERL problem-driven research through the development of multimedia exposure model and dose models. This task will contribute to the collection and analysis of samples for aggregate exposure assessments for children. Data generated from the field measurement studies will be used both as inputs and for evaluation of multimedia, multipathway human exposure models that are under development.

Clients :EPA NERL, EPA OPPTS, EPA OPP, EPA NCEA, pesticide industry

Project IDs:

ID Code :6960

Project type :OMIS