Accumulation of organic contaminants in two sediment-dwelling shellfish with contrasting feeding modes : deposit- (Macomona liliana) and filter-feeding (Austrovenus stutchburyi)

The bioaccumulation of organochlorine pesticides, PCB, PAH and chlorophenols was determined in the tellinid Macomona liliana (deposit-feeder) and the venerid Austrovenus stutchburyi (filter-feeder) at 5 stations along a contaminant gradient in Manukau harbour, New Zealand. Both shellfish showed marked gradients of contaminant concentrations from the inner-harbour to the harbour entrance. Concentrations of contaminants were similar in both species, with slightly higher PCB and PAH levels in M. liliana. Shellfish bioaccumulation relative to sediment concentration showed no marked trends in relation to harbour location. Bioaccumulation factors were similar for both species with values of 20-30 for all contaminants, except for PAH which had a value of less than 1. Mean accumulation factor values were similar for the 2 species and were principally 1-4, except for PAH, which were 0.002 and 0.14. For individual PAH, pyrene showed the highest and anthracene the lowest concentration in both the shellfish. PCB congeners 118, 153 and 138 were predominant in sediments and each of the shellfish species. The abundance and condition of M. liliana was reduced at the more contaminated sites. There are 36 references.