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ENVIRONMENTAL IMMUNOCHEMISTRY AT THE U.S. EPA, NATIONAL EXPOSURE RESEARCH LABORATORY'S HUMAN EXPOSURE BRANCH
Van Emon, J M. ENVIRONMENTAL IMMUNOCHEMISTRY AT THE U.S. EPA, NATIONAL EXPOSURE RESEARCH LABORATORY'S HUMAN EXPOSURE BRANCH. Presented at UN/International Atomic Energy Agency Meeting, Vienna, Austria, September 25-28, 2000.
More cost-effective field screening and monitoring methods will be provided to increase the amount of information available concerning the location, source, and concentration of pollutants. Rapid and sensitive immunoassays such as enzyme-linked immunosorbent assays (ELISAs) to monitor remediation and cleanup activities at Superfund sites will be developed. Each new method will be tested on real-world samples from monitoring studies. Field studies will be conducted when time and resources permit. The feasibility and application of immunosensors to provide field analytical methods for the dynamic monitoring of hazardous substances of interest to the EPA will also be investigated. Concern has been expressed for the potential exposure of individuals to toxic compounds who live near hazardous waste sites or who may become exposed through other means. Thus, the development of methods for measuring biomarkers for human exposure assessment studies is also addressed.
During the remainder of the Task several projects will be undertaken including:
- Complete the development and evaluation of bioanalytical methods for dioxin and related compounds
- Perform dioxin immunoassay analysis on samples from a dioxin SITE demonstration
- Comparison of an ELISA with gas chromatography (GC) for monitoring polychlorinated biphenyls (PCBs) in soils/sediments collected from a Superfund field demonstration
- Survey of bioanalytical methods and sensor technologies for environmental monitoring
- Development of immunoaffinity chromatography sample preparations for PCBs
- Preparation of standard operating procedures (SOPs) for each bioanalytical method developed
- Conduct yearly research meeting
- Conduct survey of high priority chemicals at National Priorities List (NPL) sites for bioanalysis suitability
- Develop new bioanalytical methods for hazardous compounds of public concern
- Perform PCP immunoassay analysis on soil and sediment samples from a Superfund site and compare with GC data
- Preparation of fact sheets and journal articles
Immunoehemical methods are responding to the changing needs of regulatory and monitoring programs and are meeting new analytical challenges as they arise. Recent advances in environmental immunoehemistry have expanded the role of immunoassays from field screening methods to highly quantitative procedures that can compete with chromatographic methods in the laboratory.
The first field trial of an immunoassay under the EPA Superfund Innovative Technology Evaluation (SITE) Program was conducted by the immunoehemistry research program of the U.S.EPA, NERL-Las Vegas. Four immunoassays to detect pentachlorophenol were evaluated and compared with a gas chromatography/mass spectrometry (GC/MS) method. Much was learned from this first field trial including appropriate quality control measures, data comparability, and how to perform a sensitive analytical method at a contaminated site. This study has become a model for subsequent field trials including immunoassays for the polychlorinated biphenyls (PCBs). Soil samples collected from a Superfund site were analyzed by a quantitative 96-well plate enzyme-linked immunosorbent assay (ELISA) developed by the NERL-Las Vegas. The performance of the ELISA was compared with that of gas chromatography (GC) using an electron capture detector (ECD). Very limited cross-reactivity was seen with 37 structurally related co-contaminants. Three extraction procedures were evaluated: an abbreviated methanol shake procedure, supercritical fluid extraction samples extracted by SFE and by Soxhiet were in close agreement with (SFE) with carbon dioxide, and Soxhiet extraction with methanol. The GC/ECD results. The simple methanol shake method yielded lower ELISA results, supporting the importance of extraction procedures in the overall analysis scheme.
This work has been funded wholly or in part by the U.S. Environmental Protection Agency and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.