EXPOSURE OF ABARENICOLA PACIFICA TO OILED SEDIMENT: EFFECTS ON GLYCOGEN CONTENT AND ALTERATIONS IN SEDIMENT-BOUND HYDROCARBONS1

Abstract

ABSTRACT A one-month field experiment was conducted to determine the alterations of specific hydrocarbons within a fine sediment mixed with oil and to assess the impact of this contamination on the deposit-feeding polychaete, Abarenicola pacifica. Fresh or weathered Prudhoe Bay crude oil was mixed with sediment in nominal concentrations between zero and 1,000 parts per million (ppm). Oiled sediment filled the exposure chambers or was placed in a layer over clean sediment. After one month of exposure under field conditions, concentrations of individual saturate and aromatic hydrocarbons in the worms’ body wall muscles were below the limits of detection (less than 0.2 ppm saturates and less than 0.08 ppm aromatics). Analyses of both saturates and aromatics in core samples of sediment systems containing or lacking worms indicated that bioturbation occurred in some instances. The relative release rates of specific aromatic hydrocarbons from sediments were greater at the surface and appeared to decrease with increasing molecular weight. The effect of exposure to oiled sediment on glycogen content of Abarenicola body wall was significant (p <0.02). Analysis of individual variability in populations sampled between February and August showed that test groups of 12 control and 12 exposed animals could be used to demonstrate a reduction of 10 milligrams per gram (mg/g) in glycogen levels resulting from environmental conditions. Within the proper testing framework, analysis of Abarenicola glycogen content could be used to assess the effects of oil spills on benthic infauna.