Detection of dioxin-like compounds with a human cell line biomarker to assess risk
- Columbia Analytical Services, Carlsbad, CA (United States)
- MEC Analytical Systems, Inc., Carlsbad, CA (United States)
A reporter gene system (RGS) assay, derived from a human liver cancer cell line, has been developed such that induction of the CYP1A1 gene and the combined firefly plasmid results in the production of the luminescent enzyme, luciferase. The assay consists of exposure of the cells to solvent controls, reference toxicants (TCDD), and organic extracts (dichloromethane) of water, tissue, or soil, for 6 to 18 hours, with the subsequent measurement of luminescence. Induction of this test system by such compounds as dioxins, furans, coplanar PCB congeners, and 4- to 6-ring polycyclic aromatic hydrocarbons (PAHs) infers these xenobiotics are present at levels that are potentially toxic, carcinogenic, or mutagenic to organisms. Test results show significant RGS induction from concentrations of inducer compounds, that if present in a typical 40 g sample, would be (in ng/g or ppb): 0.008 for Dioxin; 6.2--2,000 for a range of coplanar PCB congeners; 6.2--7,500 for specific PAHs; and 250 for a mixture of PAHs. Comparisons between the EPA Toxic Equivalent Factors (TEFs) and those generated from P450 RGS testing differ considerably. The TEFs for PCBs are significantly lower than those estimated by EPA. Some of the PAHs tested exhibit higher TEFs than the coplanar PCBs. RGS responses show a strong correlation with detailed chemical analyses of dioxins, furans, and PAHs of the same environmental samples. The RGS responses to dioxins and furans more closely compare with the total of all analytes than the TEQ values, produced after application of TEFs. Results presented will show that screening a wide area for the presence of the above chemicals is a cost-effective approach to rapidly determine the most appropriate samples to receive complete chemical characterization.
- OSTI ID:
- 452023
- Report Number(s):
- CONF-9611118--
- Country of Publication:
- United States
- Language:
- English
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