Bioaccumulation of polychlorinated biphenyls and metals from contaminated sediment by freshwater prawns,Macrobrachium rosenbergii and clams,Corbicula fluminea

Freshwater prawns,Macrobrachium rosenbergii, and clams,Corbicula fluminea, were exposed for 48 or 50 days to three concentrations of a river sediment that contained environmental contaminants such as polychlorinated biphenyls (PCBs) and metals. Sediment was obtained twice during 1980 from the same location. Prawns were exposed to the first batch, sediment 5–80, which contained higher concentrations of some metals and PCBs compared to sediment 11–80, used with the clams. The highest concentration of sediment 5–80 was toxic to the prawns; sediment 11–80 was not toxic to the clams. Tissue analyses of prawns for PCBs, as Aroclors® 1242 and 1254, demonstrated bioaccumulation. Maximum concentration of 1242 in prawns was achieved by day 7 while 1254 continued to accumulate in prawn tissues during the initial 40 days of the exposure period. The PCB sediment bioaccumulation factors (BAF) for prawns ranged from 0.11 to 0.90 for 1242 and 0.20 to 2.40 for 1254, and were highest for animals exposed to 10% sediment. Exposed clams also accumulated PCBs (1242 + 1254) from the sediment. Sediment BAFs for clams were 0.54 to 12.52 and were highest for animals exposed to 10% sediment. Analyses of clams for metals showed lead (Pb) in exposed animals at higher concentrations compared with controls. Bioaccumulation of Pb differed from PCB in that the Pb concentrations did not increase over time and concentrations were higher among animals exposed to 10% sediment compared to animals exposed to 100% sediment. Sediment 11–80 contained 99 mg/kg of Pb while exposed animals, at 48 days, contained approximately 2.2 mg/kg Pb. Analysis of clams for cadmium (Cd) showed exposed animals contained less Cd than controls.