EFFECTS ON MARINE ORGANISMS FROM POLYCYCLIC AROMATIC-HYDROCARBONS (PAH) AND OTHER CONSTITUENTS OF WASTE-WATER FROM ALUMINUM SMELTERS WITH EXAMPLES FROM NORWAY

A brief review is presented of the effects from the main stress factors in Norwegian aluminium smelter effluents: PAH, fluoride and depressed pH from the combination of Soderberg technology with treatment of gases in seawater scrubbers. The main focus is on PAH. It is shown that toxic effects from fluoride or depressed pH are usually not to be expected outside the primary dilution zone. Generally, ecological effects in the recipients are restricted to 1-2 km from the waste outfalls. The apparent discrepancy between toxicity thresholds of PAH from the literature and the merely moderate adverse effects in Norwegian recipients is considered to be due to (i) the inadequate relevancy of tests with dissolved PAH for effluents dominated by PAH in the particulate state and (ii) less availability of soot associated with oil derived PAH in sediments, and the probable role of dissolved organic matter in making pore water PAH less available than unassociated PAH in solution.