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Woods Hole Coastal and Marine Science Center > USGS Studies in Long Island Sound > Geochemistry in Long Island Sound

U.S. Geological Survey Studies in Long Island Sound:
Geology, Contaminants, and Environmental Issues

Geochemistry in Long Island Sound:
Sample Sites and Collection

Sediment cores and surficial grab samples (click here for a map showing locations) were collected in Long Island Sound for geochemical analysis (1) in North-South transects within Long Island Sound, (2) throughout the Sound for verification of sidescan sonar interpretations, (3) in study areas targeting critical habitats, and (4) in areas with good preservation of historical signals. Sampling cruises encompassed the period from 1993 to 2001.

Sediment cores were collected in 1996 using the U.S. Geological Survey's hydrostatically-damped gravity corer (HDGC), and in 2001 with a free-falling gravity corer. The HDGC collected 11-cm diameter cores of 15 to 70 cm in length in clear, polycarbonate tubing. There was minimal disturbance of the sediment surface and 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 2001 were acquired with a free-falling gravity core that sampled up to 245 cm of sediment in a PVC barrel. Cores were x-rayed, 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), pollen, foraminifera, toxicity, organic contaminants, and magnetic properties. Data and samples are archived at the USGS Woods Hole Field Center and will be made available through this website.

Chemical, Physical and Bacterial Measurements Made on Sediment Cores and Samples
Major and Trace Elements Carbon Parameters
Aluminum
Barium
Cadmium
Calcium
Chromium
Copper
Mercury
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Potassium
Silver
Sodium
Stronium
Titanium
Vanadium
Zinc
Zirconium
Total carbon
Organic carbon
Carbonate carbon
Hydrogen
Nitrogen
Physical Properties Biological Indicators Toxicity Assessment

Water Content
Grain-size distribution
Magnetic properties
Bulk Density
Gamma-emitting radionuclidies
X-radiographs

Clostridium perfringens
Foraminifera
Pollen
Sea Urchin Fertilization Toxicity Test
Sea Urchin Embryological Development Toxicity Test
10-Day Marine Amphipod Survival Test
Qualitative benthic community health
Exceedence of quantitative Sediment Quality Guidelines

 

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