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(297) Comparison Between CYP1A1-inducing Chemicals in Sediments of San Francisco Bay and Chemical and Biological Measurements.
Anderson, Jack*,1, McCoy, Daniel1, Hartwell, Ian2, Hameedi, Jawed2, Pedersen, Joel3, Carr, Scott4, 1 Columbia Analytical Services, Vista, CA, USA2 National Oceanic and Atmospheric Administration, Silver Spring, MD, USA3 University of Wisconsin, Madison, WI, USA4 U S Geological Survey, Corpus Christi, TX, USA
ABSTRACT- The San Francisco Bay was the subject of studies by NOAA and EPA in 2000 and by NOAA in 2001. In each year, 99 sediment samples distributed within strata over the entire Bay were collected and analyzed for a range of chemical and biological parameters. A biomarker assay, P450 Human Reporter Gene System (HRGS), was used to document the occurrence and distribution of CYP1A1-inducing compounds in these samples. The assay (now EPA 4425) utilizes a stably transfected human hepatoma cell line with a plasmid containing the firefly luciferase gene downstream of CYP1A1 promoter sequences. When these cells are exposed to CYP1A1-inducing compounds (PAHs, PCBs, dioxins/furans), luciferase is produced, and can be easily measured with a luminometer. The responses, expressed as ug of benzo[a]pyrene equivalents/g (B[a]PEq) from samples collected in 2000 and 2001 were quite similar (means = 21.2, 19.9; upper 99% confidence limits = 28.0, 26.9). Each year 5 stations were over 60 ug/g B[a]PEq, and the numbers of samples above the upper confidence limit were 20 and 17. The PAHs were most highly correlated with the HRGS responses (R2 values = 0.64, 0.63). At several of the stations, but not all, a high HRGS response was observed when there was a significant reduction in normal development of sea urchin embryos. In 2000, splits of extracts were first cleaned of PAHs by silica gel before HRGS testing and the results compared to high-resolution GC/MS analyses of dioxins, furans, and PCBs of 63 samples. Most samples were less than the HRGS reporting limit of 10 ng/Kg TEQ, which was confirmed GC/MS and only one sample was significantly higher by GC/MS. HRGS is an inexpensive screening tool for determining which of the numerous sediment locations sampled contain significant levels of carcinogenic and toxic compounds, and are therefore likely to exhibit degraded biological communities.
Key words: Sediments, CYP1A1 Induction, EPA Method 4425, PAHs, dioxins, furans, PCBs
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