RELATIONSHIP BETWEEN SOFT-BOTTOM MACROFAUNA AND POLYCYCLIC AROMATIC-HYDROCARBONS (PAH) FROM SMELTER DISCHARGE IN NORWEGIAN FJORDS AND COASTAL WATERS

Data from monitoring surveys were used to test the responses of soft b ottom fauna in Norwegian fjords and coastal waters affected by effluen ts from aluminium and manganese alloy smelters to effluent discharges. Generally, polycyclic aromatic hydrocarbons (PAHs) have been consider ed the main threat to the biota in the receiving waters. Data from a t otal of 57 quantitative stations, of which 30 were simultaneously samp led for sedimentary PAHs, were analysed. Canonical Correspondence Anal ysis (CCA) was used to evaluate species patterns in relation to sedime nt PAH concentrations and natural environmental variables such as dept h, sediment characteristics and riverine input. The PAHs varied from v ery high concentrations (760 pg g(-1) total PAH) at the most impacted sites to background levels in reference areas. Despite previous report s of little to no effects of the effluent discharges, the analyses ide ntified significant species changes along PAH gradients, which could b e associated with feeding modes. In particular, a number of carnivorou s polychaetes had their distribution optima in the most affected areas . Based on species statistics calculated by CCA, response functions we re fitted for the species on PAH and used to establish a generalised e xpression of trophic community structure in relation to PAH concentrat ions. At low PAH levels, the carnivores represented 15 to 20 % of:the specimens in the communities, but the proportion began to increase fro m about 10 mu g g(-1) and exceeded 50 % at 100 mu g g(-1) total PAH. T he faunal changes were most evident in shallow waters, possibly reflec ting the effects of dissolved PAHs to which the species may react more directly than they do to sedimentary particle-associated PAHs.