EFFECTS OF BLACK ROCK HARBOR SEDIMENTS ON INDEXES OF BIOTRANSFORMATION, OXIDATIVE STRESS, AND DNA INTEGRITY IN CHANNEL CATFISH

Selected biochemical responses were measured in channel catfish (Ictal urus punctatus) exposed in the laboratory to sediments obtained from e ither of two sites in Long Island Sound, CT. These sites were Black Ro ck Harbor, which is highly contaminated with various aromatic hydrocar bons, and a relatively uncontaminated reference site. Livers and bile were removed from fish on days 2, 7, 14, and 28 following the initiati on of sediment exposures and examined for responses associated with (1 ) xenobiotic biotransformation, (2) oxidative stress, and (3) DNA inte grity. Relative to reference sediment exposures in fish, exposures to Black Rock Harbor sediments elicited on at least two of the four sampl ing points significant (P < 0.05) increases in: (1) phase I biotransfo rmation enzyme activities (EROD and ECOD) and concentrations of bile m etabolites of polycyclic aromatic hydrocarbons (PAHs); (2) antioxidant enzyme activities (SOD and catalase), concentrations of reduced and o xidized glutathione, and malondialdehyde (an index of lipid peroxidati on); and (3) the fraction of DNA as single-stranded DNA following alka line unwinding (an index of strand breaks). The results of this study support hypotheses concerning mechanistic relationships in benthic fis h among the metabolism of sediment-associated aromatic hydrocarbons, t he generation of free radical intermediates, and mutagenesis. Furtherm ore, these results support the utility of biochemical responses as too ls for assessing contaminant exposures and sublethal effects in aquati c animals.