National park index sites are being used as platforms for studying the occurrence of anthropogenic chemical contamination at continental U.S. sites that are minimally impacted by direct human activity. Two fish species (bottom feeding and higher predator), sediment, water, and plant tissue collected at twelve parks will be analyzed for a suite of contaminants including volatile organic compounds, polynuclear aromatic hydrocarbons, individual congeners of polychlorinated biphenyls, selected pesticides, and mercury. Most of this target list comprises chemicals suspected to be endocrine disrupting compounds (EDCs). Fish from a probability sample of wadeable stream sites from the Mid-Atlantic Integrated Assessment (MAIA) Project will be subjected to the same protocol as the index site fish. The concentrations of contaminants found in the index site fish will be compared to the distributions of concentrations found in the MAIA fish, the latter being assumed to be exposed to a broad range of stressors and to be representative of a large region of the U.S. Results from the media other than fish collected at the index sites cannot be compared to distributions obtained for MAIA sites; available literature data for similar matrices will be used to assess the relative magnitude of these contaminant loads.
Because the index sites are purportedly less subject than typical continental U.S. ecosystems to chemical contamination, conventional analytical approaches would be expected to produce many results below method detection limits. Maximizing the percentage of useable data by improving detection limits would allow more detailed interpretation of the results. Therefore, new analytical techniques with potentially superior performance to conventional methods will be developed and used. The emergent analytical techniques will be compared with conventional methods to assess the relative figures of merit of the methodologies. New analytical approaches to be tested include accelerated-solvent, solid-phase, and microwave-assisted extraction procedures; vacuum distillation of volatile organic compounds; multidimensional separation methods; state-of-the-science mass spectrometry techniques; direct analysis of solid samples for mercury; rapid screening approaches including direct aqueous injection analysis and capillary electrophoresis/laser induced fluorescence; and elemental speciation. A screening procedure for contaminants not in the target suite will also be developed.
The contaminant levels found
in the index site fish will be analyzed, using data on regional chemical
contaminant sources, geochemistry, and meteorology, in an attempt to
assess the relative importance of local and regional sources, compared
to long-range transport. It is also hoped that some Index Sites will
become long-term platforms to develop and evaluate new monitoring approaches.
Report on Contaminant Screening Study