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IMMUNOCHEMICAL DETERMINATION OF DIOXINS IN SEDIMENT AND SERUM SAMPLES
Nichkova, M., E. Park, M. E. Koivunen, Kamita, S,G., S. J. Gee, J. C. Chuang, J M. Van Emon, AND B. D. Hammock. IMMUNOCHEMICAL DETERMINATION OF DIOXINS IN SEDIMENT AND SERUM SAMPLES. TALANTA 63(5):1213-1223, (2004).
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
Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are considered highly toxic contaminants and the environmental and biological monitoring of these compounds is of great concern. Immunoassays may be used as screening methods to satisfy the growing demand for rapid and low cost analysis. In this work we describe the application of an immunoassay that uses 2,3,7-trichloro-8-methyldibenzo-p-dioxin (TMDD) as a surrogate standard for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to sediment and human serum samples. Sample extraction and preparation methods were developed with the aim to establish the simplest, cost-effective and efficient removal of the matrix interferences in the Enzyme-Linked Immunosorbent Assay (ELISA). The overall method for sediments is based on a hexane extraction; clean up by a multilayered silica gel column and an activated carbon column; an organic solvent exchange with DMSO-Triton X-100 and ELISA measurement. The gas chromatography - high resolution mass spectrometry (GC-HRMS) validation studies (n=13) revealed that the method is suitable for the TEQ (toxic equivalents) screening of dioxin in sediments with a method detection limit of about 100 pg g-1 dry sediment with a precision of 13-33%RSD. The analysis of a large number of samples originating from different sources would be required to establish more precisely the screening level, as well as the number of false positives and negatives of dioxin TEQ by the immunoassay for sediments. The immunoassay method for sediment analysis offers improvement in speed, sample throughput, and cost in comparison to GC-HRMS. Dioxins were determined in serum samples after a simple liquid-liquid extraction and solvent exchange into DMSO-Triton X-100 without further dilution. The current method (approximate method LOQ of 200 pg ml-1serum) is not sufficiently sensitive for the determination of dioxins in serum to measure acceptable exposure limit.
The U.S. Environmental Protection Agency through its Office of Research and Development (ORD) partially funded and collaborated in the research described here under contract No. GS-10F-00275K to Battelle. It has been subjected to the Agency's review and approved for publication. Mention of trade names and commercial products does not constitute endorsement or recommendation for use. This research is also funded by grants from the National Institute of Environmental Health Sciences 5 P42 ES04699 and NIEHS Center for Environmental Health Sciences P30 ES05707.