Geochemistry in the New York Bight:
Sample Sites and Collection

Sediment cores and surficial grab samples were collected for geochemical analysis (1) in the vicinity of discontinued dumpsites, (2) along the thalweg and basins of the Hudson Shelf Valley for approximately 100 km seaward, (3) on the shelf surrounding the 6-mile disposal site, and (4) between the Hudson-Raritan estuary and the Hudson Shelf Valley. Sampling cruises encompassed the period from 1993 to 2000.

Sediment cores were collected in 1993, 1997, and 1998 using the U.S. Geological Survey's hydrostatically- damped gravity corer, which collected 11-cm diameter cores of 20 to 70 cm in length in clear, polycarbonate tubing. There was minimal disturbance of the sediment surface and, for many cores, a video camera was mounted on the frame of the corer to record the entry of the corer into the sediment. On deck, the cores were capped, described, and stored vertically for later sectioning and analysis. Cores collected in 1994 were acquired with a free-falling gravity core that sampled up to 200 cm of sediment in a PVC barrel. Cores were xrayed, extruded in the laboratory, subsampled at selected intervals, and aliquots separated for analysis.

Surface sediment samples were collected with a teflon-coated Van-Veen grab sampler with attached bottom video. On deck, the sediment-grab was photographed, overlying water removed, and the upper 2-cm of sediment collected with a Teflon-coated flat-bottom scoop. Each sediment sample was placed in a pre-cleaned plastic container and aliquots separated for geochemical and other analysis.

Geochemical Data Collected

Physical descriptions, X-radiographs (relative density) and Multi-Sensor Core Logger Data (magnetic susceptibility, bulk density, and P-wave travel time) were collected on whole sediment cores. Sectioned core samples and surface grab samples were analyzed for physical properties (water content, sediment grain size) and for chemical composition after total digestion. Measured parameters included both contaminants and the major and trace elements that characterize natural sediments (see table). Selected samples were also analyzed for radiochemistry (210Pb and 137Cs), toxicity, organic contaminants, and magnetic properties. Data and samples are archived at the Woods Hole Field Center of the U.S. Geological Survey and will be made available through this website.