Polycyclic aromatic hydrocarbon contamination in South Carolina salt marsh-tidal creek systems: relationships among sediments, biota, and watershed land use.

Sediments and biota from 11 tidal creeks were sampled and classified into forested, suburban, and urban/industrial watershed land-use categories. Total PAH levels ( summation operatorPAH(16)) in sediments were significantly higher in urban/industrialized creeks (5,795 +/- 1,173 ng/g) compared to suburban (793 +/- 131 ng/g) and forested (238 +/- 34 ng/g) creeks. No differences in summation operatorPAH(16) levels among land-use classifications were found for either oligochaetes (Monopylephorus rubroniveus) or grass shrimp (Palaemonetes pugio). However, summation operatorPAH(16) levels in grass shrimp were related to sediment summation operatorPAH(16) levels and summation operatorPAH(16) levels in oligochaetes and grass shrimp eggs were related to impervious cover in the watershed. Diagnostic ratios suggest that the primary sources of PAH in suburban and urban/industrialized creeks are pyrogenic. Carcinogenic PAH contents of sediments and biota were related to impervious cover. While human exposures to these sediment-associated carcinogens were not assessed, levels of several carcinogenic PAHs in sediments of urban/industrial tidal creeks were above the levels that represent an increased cancer risk in humans.