Presentation of a general algorithm to include secondary poisoning in effect assessment.

A general algorithm for effect assessment on secondary poisoning for birds and mammals is presented. This algorithm (Maximum Permissible Concentration = NOECbird/mammal/BCF) was drawn up by analysing an aquatic food chain (water--fish--bird or mammal) and a terrestrial food chain (soil--worm--bird or mammal). NOECs and bioconcentration factors (BCFs) were collected for a set of selected compounds: lindane, dieldrin, cadmium and mercury in both water and soil, PCB153 only in water and DDT and PCP only in soil. BCFs for the terrestrial pathway are frequently < 1 and rarely above 10, though for the aquatic pathway BCFs up to 10(4) were found for the same compounds. By calculating MPCs for fish-eaters and comparing these to MPCs calculated for aquatic organisms, secondary poisoning could be a critical pathway for methyl-mercury and PCB153. For lindane the conclusion depends on whether a separate or combined data set is chosen for birds and mammals. By calculating MPCs for a standard soil situation and comparing these to MPCs for terrestrial organisms, secondary poisoning could be a critical pathway for cadmium and methyl-mercury.