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AN ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) FOR DETERMINING DIOXINS IN SEDIMENT AND SOIL SAMPLES
VAN EMON, J. M., J. C. CHUANG, B. LORDO, M. NICHKOVA, S. J. GEE, AND B. HAMMOCK. AN ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) FOR DETERMINING DIOXINS IN SEDIMENT AND SOIL SAMPLES. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
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
The dioxins comprise a family of compounds chemically referred to as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The most toxic of these compounds is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a known human carcinogen. Dioxins are formed mainly as by-products of industrial processes (e.g., waste incineration) and can also be produced from natural processes (e.g., volcanic eruption or forest fire). Exposure to dioxins has been linked to various adverse health effects such as severe skin disease (chloracne), birth defects, and an increased risk of cancer. Non-occupational routes of exposure to dioxins include inhalation of contaminated air, ingestion of contaminated food and non-food items, and dermal contact. Conventional analytical methods for determining dioxins rely on sophisticated instrumentation, such as gas chromatographs and high resolution mass spectrometers. These methods are typically time consuming and costly, severely limiting the number of samples that can be processed. Low-cost field screening methods and efficient high-capacity laboratory methods are needed to support large-scale environmental monitoring and human exposure assessment studies. Immunoassays, such as the enzyme-linked immunosorbent assay (ELISA), use antibodies to analyze samples rapidly and cost effectively. An ELISA was developed at the University of California, Davis for the detection of various dioxins. More than 80 sediment and soil samples from a U.S. Environmental Protection Agency (U.S. EPA) Superfund site were analyzed by the ELISA and compared with an instrumental method. The findings suggest that the ELISA method can be used as a quantitative monitoring tool for determining dioxin levels in monitoring studies and to determine dioxin toxic equivalent values in environmental samples.