Dietary transfer of fluoranthene from an estuarine oligochaete (Monopylephorus rubroniveus) to grass shrimp (Palaemonetes pugio): Influence of piperonyl butoxide.

The objective of this study was to determine the potential for dietary transfer of sediment-associated fluoranthene from tubificid oligochaetes (Monopylephorus rubroniveus) to grass shrimp (Palaemonetes pugio). Grass shrimp, either in the presence or absence of sublethal waterborne concentrations of the metabolic inhibitor, piperonyl butoxide (PBO), were fed fluoranthene-dosed oligochaetes for 5-days. All grass shrimp bioaccumulated fluoranthene; however, bioaccumulation was 3X higher in the presence of PBO. Trophic transfer coefficients (TTCs) were 0.02 and 0.01 in the presence and absence of PBO, respectively. Following the 5-day accumulation period, shrimp in both treatments were allowed to depurate for 3 days. Depuration rates were significantly higher in PBO-exposed shrimp. These results demonstrated that sediment-associated fluoranthene can be transferred through the diet from oligochaetes to grass shrimp, and the presence of PBO enhanced fluoranthene bioaccumulation. However, the comparatively low TTCs suggest that biomagnification of fluoranthene in estuarine food webs is low.

An evaluation of polycyclic aromatic hydrocarbon (PAH) runoff from highways into estuarine wetlands of South Carolina.

This study investigated the concentrations and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) associated with highway runoff into adjacent estuarine wetlands from road segments representing three levels of average daily traffic (ADT): low (<5,000 ADT), moderate (10,000-15,000 ADT), and high use (>25,000 ADT) based on SC Department of Transportation data. Sediments from three estuarine wetland habitats (tidal creeks, Spartina marsh, and mud flats) adjacent to these road segments were sampled to represent nine highway use class/habitat type combinations. Surficial sediments were collected at 3, 25, and 50 meters from the upland/wetland interface along transects established perpendicular to the road at each site, with additional samples taken from the road berm. Average PAH concentrations, representing 25 compounds, ranged from 3.9 to 11,000 ng/g dry weight. Berm samples had significantly greater total PAH concentrations than samples taken in any of the wetland habitats. Average total PAH concentrations decreased with increasing distance from the road berm within the wetland habitats sampled, but the differences were not statistically significant. Average total PAH concentrations also were not significantly different among the wetland habitats compared. Analysis of PAH profiles indicated that the PAH source was dominated by pyrogenic combustion products rather than from petrogenic sources. This, combined with the presence of dibenzothio-phene, which is a tire oxidation product, indicated that the primary source of PAHs was related to vehicles. Two sites with total PAH concentrations exceeding published bioeffects levels were resampled for bioassay tests using the amphipod Ampelisca verrilli, the polychaete Streblospio benedicti, and the clam, Mercenaria mercenaria, with the first two assays conducted under UV lighting since previous studies had demonstrated enhanced UV toxicity of PAHs for these species. No toxicity was observed in the amphipod or polychaete assays. Toxicity was observed in the juvenile clam assay at one site, possibly due to the combined effects of PAHs and other contaminants present.

Tidal creek and salt marsh sediments in South Carolina coastal estuaries: I. Distribution of trace metals.

Twenty-eight tidal creeks were sampled along the South Carolina coast in the summer of 1995 to determine the levels of sediment trace metal contamination associated with different types and varying levels of human development in their watersheds. The particle size and total organic carbon (TOC) content of creek sediments in developed watersheds (i.e., industrial, urban, and suburban) were similar to that in watersheds with little or no development (i.e., forested or reference). Those trace metals commonly associated with urban and industrial sources, including Cu, Cr, Pb, Zn, Cd, and Hg, were in significantly higher concentrations in tidal creeks located in industrial/urban watersheds compared to the suburban and forested watersheds. Sediment trace metal concentrations were similar for creeks located in suburban and forested watersheds and 2 to 10 times lower than the creeks located in industrial/urban watersheds. Concentrations of trace metals primarily associated with the natural weathering of basement rock, including Al, Fe, As, Ni, and Mn, were not significantly different among watershed types. Four of the tidal creek-salt marsh systems were extensively sampled from the creek channel to the marsh-upland interface to characterize sediment trace metal spatial distributions within creek-marsh systems. Sediment particle size, TOC, and trace metal concentrations varied spatially within each creek-marsh system depending on the type of development in the watershed and the probable source of metals. The creek-marsh system selected to represent the industrial development had significantly higher "anthropogenic" trace metal concentrations compared to the other creek-marsh systems. This system also had trace metal distributional patterns that appeared to be associated with several localized sources of metals on the marsh surface. Both the "anthropogenic" and "natural" trace metal concentrations and spatial distributions were similar among and within the forested and suburban creek-marsh systems.http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p445.html

Tidal creek and salt marsh sediments in South Carolina coastal estuaries: II. Distribution of organic contaminants.

Twenty-eight tidal creeks along the South Carolina coast were sampled during the summer of 1995 to determine the levels of sediment contamination including organic chemicals (i.e., polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and DDT and its metabolites) associated with different types and varying levels of watershed development (i.e., industrial/urban, suburban, forested, and salt marsh). Organic analysis utilized high-performance liquid chromatography (HPLC) with fluorescence detection and capillary gas chromatography-ion trap mass spectrometry (GC-ITMS) for PAHs, and gas chromatography with electron capture detection (GC-ECD) for pesticides and PCBs. Results indicated that creeks with industrial/urban watersheds had significantly higher concentrations of PAHs, PCBs, and DDT compared with creeks with suburban and forested (reference) watersheds. The suburban watershed class of creeks had concentrations of half the PAH analytes and the total PCBs which exceeded the concentrations found in the forested watershed class of creeks. The spatial distribution of organic contaminants was evaluated in four of these tidal creek-salt marsh systems representing urban/industrial, suburban, and forested watersheds, from the creek channel to the adjacent uplands. The distribution of organic contaminants within each representative creek was not concordant with the total organic carbon or the clay content of the sediment. The representative industrial/urban creek-marsh system, Diesel Creek, had the highest concentration of PAHs in the creek channel and the highest concentration of PCBs and DDT on the marsh surface, primarily in the upper portion of the system. The representative suburban creek-marsh system, Shem Creek, had elevated levels of both PAHs and PCBs throughout the entire system. This system also had one site with a total PAH concentration of 324,000 ppb and a total DDT concentration that was 20-100 times higher than the other sites. One of the representative forested creek-marsh systems, Rathall Creek, had low levels of the three organic contaminants except for one sampling site that had PAH concentrations a factor of 10 higher than the other sites. The other representative forested creek-marsh system, Long Creek, had low levels of PAHs and PCBs, but elevated levels of DDT were observed, particularly in the upper portion on the marsh surface. The results of this study suggest that (1) anthropogenic alteration of the land cover in the watersheds of tidal creek-salt marsh systems may increase the organic contaminant loadings in the sediment, and (2) tidal creek-salt marsh sediments, particularly in the creek channel, are repositories and potentially conduits of organic contaminants from the upland environment to the deeper estuarine areas.http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p458.html