Water quality conditions near Cumberland Island, Georgia
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This paper describes water quality information compiled as part of a report to the National Park Service on the water resources and habitat conditions of Cumberland Island National Seashore. Observations of nutrients, bacteria, dissolved oxygen, and contaminants in Cumberland Sound were obtained from state and federal agencies (particularly data collected by the Coastal Resources Division (CRD) of the Georgia Dept. of Natural Resources) and from the literature. Dissolved nutrient concentrations (orthophosphate, total dissolved phosphorus, nitrate plus nitrite) were considered fair to good according to the U. S. Environmental Protection Agency (EPA) National Coastal Condition Report II criteria. Bacterial concentrations (fecal coliform) did not show evidence of problems. Dissolved oxygen levels were sometimes critically low, particularly during summer: measurements made by CRD at 20 stations between 2000 and 2004 were less than 4 mg/L 18% of the time. Although it is not clear the extent to which this is a natural phenomenon, these low values warrant continued observation. This review also suggests potential problems in terms of mercury and several pesticides (i.e. dieldrin, lindane, 4,4′-DDD), which may be due to legacy contamination of the sediment or to continued input from both point and non-point sources. Continued monitoring of water conditions (particularly dissolved oxygen) and forthcoming observations of contaminant concentrations in organisms and sediment taken as part of the EPA National Coastal Assessment Program will enable better evaluation of coastal water resources in the region.