PRESENTATION OF A GENERAL ALGORITHM TO INCLUDE EFFECT ASSESSMENT ON SECONDARY POISONING IN THE DERIVATION OF ENVIRONMENTAL-QUALITY CRITERIA.2. TERRESTRIAL FOOD-CHAINS

In a previous study a simple algorithm was presented for effect assess ment on secondary poisoning of birds and mammals. This algorithm (MPC = NOEC(fish-eater)/BCF(fish)) was drawn up by analyzing a two-step aqu atic food chain (water-fish-bird/mammal). The algorithm was used to te st whether quality criteria set for surface water, based on effect ass essment for aquatic organisms, constitute a ''safe'' level for seconda ry poisoning. The present study analyzes whether this algorithm can eq ually well be used for effect assessment in a terrestrial food chain. The pathway soil-earthworm-bird/mammal was used as an example for a te rrestrial food chain. Literature data of six selected compounds (linda ne, dieldrin, DDT, PCP, cadmium, and mercury) on both bioconcentration factors for earth-worms and toxicity data for birds and mammals were studied. Important differences were found between BCFs for this terres trial pathway and BCFs for the aquatic pathway analyzed in the previou s study. It was found that BCFs for earthworms were more dependent on soil-related properties than on compound-specific properties. Hence, i t was concluded that the algorithm MPC = NOEC(worm-eater)/BCF(worm) ca n be used only for effect assessment on terrestrial food chains in def ined situations. By calculating maximum permissible concentrations for secondary poisoning (MPC(sp)) for a standard soil situation and compa ring these to MPCs for soil organisms, it was concluded that secondary poisoning could be a critical pathway for cadmium and methyl mercury. For methyl mercury secondary poisoning in an aquatic food chain was a lso a critical pathway. Secondary poisoning of fish-eating birds and m ammals is not likely to occur for cadmium at concentrations in water b elow the MPC calculated for aquatic organisms. (C) 1994 Academic Press , Inc.