BIOACCUMULATION, GROWTH AND LARVAL SETTLEMENT EFFECTS OF SEDIMENT-ASSOCIATED POLYNUCLEAR AROMATIC-HYDROCARBONS ON THE ESTUARINE POLYCHAETE,STREBLOSPIO-BENEDICTI (WEBSTER)

Macrobenthos of the pristine North Inlet, SC, USA and urbanized Murrel l's Inlet, SC, estuaries are predominated by the cosmopolitan spionid polychaete Streblospio benedicti. (Webster) Laboratory experiments wer e conducted to measure larval settlement and metamorphosis, and sub-ad ult bioaccumulation/growth rates of S. benedicti when exposed to contr olled concentrations of sediment-associated polynuclear aromatic hydro carbons. Larval settlement/metamorphosis was reduced, but not signific antly affected (relative to controls) by 1X, 5X and 10X background PAH mixture concentrations of the six most abundant sediment-associated P AHs found in urbanized Murrell's Inlet (1X = 0.9 mu g PAH per g dry se diment). Bioaccumulation of the most abundant sediment-associated PAH, fluoranthene (FL), was very high in this PAH tolerant species-9.5-13. 7X FL sediment concentrations after 28-day exposures. 28-day exposures to 0.26 and 2.4 mu g FL.g(-1) caused no significant mortality, and si gnificantly effected positive average weight gains in S. benedicti up to 18 days exposure. However, dramatic and significant weight declines occurred from days 18-28 in both FL treatments. Such a strong toleran ce of PAH may explain why these polychaetes are not limited to pristin e geographic areas, but can, as numerous field studies have shown, rec ruit well into hydrocarbon-contaminated and organically enriched sedim ents. (C) 1997 Elsevier Science B.V.