Acute cadmium toxicity values ranged from 0.5 mg/L for rainbow trout [14] to 18,000,000 mg/L for an alterfly [60]. Within the benthic trophic group, various species of amphipods were more sensitive than others. The 10th percentile values for all species,zooplankton, ben thos, and fish were 5.1, 4.0, 12.3, and 0.9 mg/L, respectively (Table 4)