Uptake and transfer of high PCB concentrations from phytoplankton to aquatic biota

The uptake and transfer of 2,2′,4,4′-tetrachlorobiphenyl (an isomer of polychlorinated biphenyls, PCBs) in the culture of two species of phytoplankton, Nannochloropsis oculata and Isochrysis galbana, to brine shrimp (Artemia sp.) nauplii and hard shell clam (Meretrix lusoria) were investigated in a short-term laboratory ecosystem. Three PCB concentrations, 0 ppb, 50 ppb and 500 ppb, were prepared in the algal culture for examing the levels of PCB bioaccumulation and growth effects on these biota. Artemia and hard shell clam each when exposed to 500 ppb contaminated Nannochloropsis and Isochrysis for 4 d could significantly bioaccumulate PCB concentrations up to 318.81 ppm and 22.55 ppm (dry basis), respectively. This may account for the high PCB residues that bioaccumulated in contaminated Nannochloropsis (257.52 ppm) and Isochrysis (64.22 ppm) through the aquatic food chain. Biomass of PCB treated algae were apparently depressed (p < 0.05) relative to that of the control group (0 ppb). Growth conditions (length and larva/mL) of Artemia when fed with Nannochloropsis under PCB environments also showed stronger inhibition effects compared to that of the control group (p < 0.05).