Evaluation of non-specific immune functions in dab, Limanda limanda L., following short-term exposure to sediments contaminated with polyaromatic hydrocarbons and/or polychlorinated biphenyls

Experimental exposure tanks were set up containing ‘clean’ marine sediment spiked with set doses of polyaromatic hydrocarbons (PAH), or polychlorinated biphenyls (PCB), or both. Reference tanks contained only ‘clean’ sediment. Female dab Limanda limanda L., exposed to these sediments for 7 days showed no differences in serum total protein concentration, serum lysozyme activity or body growth. Their kidney leucocytes were assayed for extracellular production of reactive oxygen species of the phagocytic respiratory burst. No significant differences in superoxide anion (O2−) production were found between fish exposed to the ‘spiked’ sediments and those on the ‘clean’ reference sediment. The production of hydrogen peroxide (H2O2) was, however, reduced in the fish held on the PAH and PAH/PCB spiked sediments. H2O2 levels for fish exposed to PCBs alone, did not differ significantly from those of control fish. Our results suggest that the decrease in H2O2 production was due to exposure to PAHs, rather than to PCBs.