Analysis of Trace Metals in Bottom Sediments in Support of Deepwater Biological Processes Studies on the U.S. Mid-Atlantic Continental Slope and Rise

摘要

Sediment samples collected during the first four cruises to the continental slope and rise off the Mid-Atlantic states have been analyzed for 12 metals (Al, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V, and Zn). Because of its high concentration in drilling mud, Ba is most commonly measured to trace drilling mud in the marine environment. In the study only small changes in Ba concentrations in sediments have been noted to date. In one core collected on Cruise 3 from Station 1 adjacent to the drilling in Block 372, the concentration of Ba was 13 percent higher in the surface sediment than deeper sediment. This enrichment is probably not harmful to benthic organisms. The strongest signal from drilling mud was observed in sediment trap samples placed within the upper 850 m of the water column on a subsurface mooring 1.8 km south-southwest of the drilling rig.