Conclusions

The natural waters of the Hudson Basin provide some of the best examples of the use of dated sediment cores to derive contaminant chronologies. The chronologies provide a basinwide, multicon-taminant perspective that has significantly added to our understanding of the sources, fate, and transport of particles and associated contaminants in the Hudson. The success of regulatory efforts is evidenced in the significant declines in concentration of many contaminants over the past few decades. Analyses of dated sediments also play a central role in areas of continuing concern and research interest, including the transport of PCBs and metals from the Upper Hudson, the spread of contaminants from other Superfund sites, biologically mediated transformations of contaminants, and atmospheric fluxes of contaminants.

The archiving of well-dated sediment samples is a critical component of our research approach. Samples initially collected and analyzed for PCBs, chlorinated hydrocarbon pesticides, and a few metals (Cu, Pb, and Zn) have formed the basis of our studies of dioxins, PAH, APEO, and a number of additional trace metals (Hg, Cr, As, Sn, Cd, Sb, Ag and others). We are currently using archived harbor sediment samples to provide historicalperspective on levels of polybrominated diphenyl ethers, contaminants associated with the World Trade Center disaster. We look forward to more detailed studies of several contaminants (Hg, APEOs, chlordane) and to continued application of state of the art analytical techniques (for example, compound specific GC/IRMS) to extract the maximum amount of information from a unique set of sediment samples.

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