Heavy Metal Pollutants in Organic-Rich Muds of the Pamlico River Estuarine System: Their Concentration, Distribution, and Effects upon Benthic Environments and Water Quality

摘要

Analyses of major, minor, and trace elements within the organic-rich muds cored at 153 stations within the Pamlico River estuarine system document specific lateral and vertical distribution and concentration of metals within the basin and define environmental conditions favoring heavy metal enrichment. Anthropogenic sources are believed to be largely responsible for heavy metal enrichment within the Pamlico River estuarine system. Sediments in the vicinity of known point source discharges are enriched in specific metals by factors up to 14 times as compared to sediments in other portions of the Pamlico River. Surface sediments have been enriched up to and occasionally in excess of 100 times the elemental concentrations occurring in sediments deeper in the cores. These areas have surface sediments that are enriched in one or more of the critical elements and include the eight EPA priority pollutant metals (As, Cr, Cd, Cu, Ni, Pb, Zn, and Hg) and other important trace elements (Co, Mn, Mo, Ti, V, F, and the nutrient element P). Enrichment is determined by comparing the concentration for each critical element to the trimmed mean for surface samples in the estuarine system.