The impact of toxic waste dumping on the submarine environment: New York Bight, New York.

摘要

The goal of this study was to determine the impact of toxic waste dumping on the submarine environment. Water samples from ten core sections collected from the Mud Dump and Sewage Sludge Sites in the New York Bight and their adjacent areas were analyzed for metal contents. The water samples included surface, bottom, and interstitial waters.; Measurements of pH and Eh of surface and bottom waters indicated a downward trend in pH values and a positive trend in Eh values. The decrease of pH values can be attributed to the decay of organic matter at the water/sediment interface. The positive trends of Eh indicate the presence of oxidizing agents in surface and bottom waters.; Although decreasing values of pH and Eh were recorded below the water/sediment interface, in some cores the values increased. Decreasing values of the pH and Eh below the water/sediment interface are due to anaerobic-bacterial activities that result in anoxic conditions, whereas, increasing values of pH and Eh are caused by a higher concentration of dissolved oxygen in the collected samples that may have come from strong oxidizing agents.; The following metals: Cd, Co, Cs, Cr, Cu, and Zn were recorded in varied concentrations in the surface, bottom, and interstitial waters of the collected core samples. The high concentrations of these metals in surface and bottom waters may be the result of streets runoff induced by rainfall in the source areas for dredged-material. The metals would have transferred from this dredged material to the overlying water across the water/sediment interface. On the other hand, the high concentrations of these metals in the interstitial waters may be related to the dumped materials in these two sites.; Metal fluxes of Cu, Mn, and Zn from the dredged materials to the overlying waters were calculated and evaluated. The research indicated that the Cu, Mn, and Zn were transferred from the sediments to the overlying waters at almost all stations. However, two stations showed an opposite trend where Cu was transferred from the overlying waters into the sediments.; Diagenetic modifications affected the physical and chemical properties of the bottom sediments. These diagenetic modifications include dissolution, compaction, oxidization, reduction, and particle size distribution.; Radionuclide dating using Cs137, K40, and Pb210 in three selected stations indicate two major types of dumping events. The first event is prior to 1950 and is recorded in the bottom portion of the cores where these elements are represented by low values. The second event is post 1950 and is recorded in the top portion of the core, where these elements are detected in high values.