Bulk Atmospheric Deposition in the Charleston Harbor Watershed

Abstract

Nutrient levels in coastal waters are significantly enhanced through atmospheric deposition. Bulk atmospheric deposition was sampled at 10 different sites throughout the Charleston Harbor watershed. Fluoride, chloride, phosphate, nitrate, and sulfate concentrations in the samples were determined with ion chromatography. Sulfate concentrations showed no statistically significant spatial variability. However, chloride and fluoride concentrations are found to be higher in samples from oceanside sites vs. the inland sites, presumably because of higher concentrations of sea spray aerosols. Samples from inland sites had higher concentrations of nitrates, presumably because of stronger influences of anthropogenic sources and continental dust aerosols. Samples from urban oceanside sites had higher fluoride, chloride, and nitrate concentrations than did samples from rural oceanside sites, suggesting an anthropogenic influence. Higher chloride and nitrate concentrations were noted in samples associated with Hurricane Opal.