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BIOAVAILABILITY OF ARSENIC, CHROMIUM, AND COPPER FROM CCA CONTAMINATED SOILS AND DUSTS
Citation:
Coppedge, E A., S L. Harper, K Bradham, AND R. Keys. BIOAVAILABILITY OF ARSENIC, CHROMIUM, AND COPPER FROM CCA CONTAMINATED SOILS AND DUSTS. Presented at The Southeastern Regional Meeting of the American Chemical Society, Research Triangle Park, NC, November 10-13, 2004.
Impact/Purpose:
The objective of this task is to develop state-of-the-science methods for evaluating toxic elements. These methods will include measuring bioavailable concentrations of toxic elements as well as enhanced traditional methods. Once established, the performance of these methods will be demonstrated on a small set of samples. Procedures will be documented such that they are readily transferable to EPA and non-EPA researchers.
Specific objectives of this task include:
1) Development of more sensitive and rapid quantitative procedures for evaluating exposure to toxic elements.
2) Assessment of the bioavailability of toxic elements in environmental media using bioavailability tools.
3) Application of this data to improve the scientific basis of site and source specific risk assessments.
4) Application of these methods to fill critical data gaps identified in the aggregate/cumulative exposure and risk research area of the Human Health Risk Assessment research plan.
Description:
It is estimated that 70% of single family homes have pressure-treated wood decks or porches and 14% of playground equipment uses pressure-treated wood. This popular form of wood contains chromated copper arsenate (CCA), which is an antimicrobial pesticide and is currently undergoing a rigorous risk assessment by the U.S. Environmental Protection Agency (EPA). Although manufacturers signed an agreement with EPA for voluntary cancellation of the registration of CCA-treated wood for residential uses beginning January 1, 2004, pressure-treated wood typically lasts 20 - 40 years, thus posing a potential for long-term exposure. The following projects will produce data under varying environmental conditions to help establish relationships between total concentrations and bioavailable concentrations to yield a better understanding of the absorbed dose of toxic elements. The bioavailability approach seeks to reduce uncertainty of total concentration analyses, which may over or under estimate health hazard, provide inaccurate risk assessments, and inappropriate risk-reduction expenses.
EPA's National Exposure Research Laboratory (NERL) is collaborating with the U.S. Department of Housing and Urban Development in the nationwide "American Healthy Homes Survey", which will provide data from a national cross-section of residential soils collected near CCA-treated wood outside homes and indoor house dusts. NERL is also collaborating with EPA's National Risk Management Research Laboratory (NRMRL) on a research project evaluating the effectiveness of coatings in reducing dislodgeable arsenic (As) from CCA-treated wood. NERL's main role in the project is to use bioassays, including earthworms and lettuce, to investigate the bioavailability of As, Chromium (Cr), and Copper (Cu) in the soil below coated CCA mini decks. Results to date show that total arsenic in the mini decks field control soils are below background concentrations. The results to date for both projects will be presented.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.