Chronic sensitivity of White sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) to cadmium, copper, lead, or zinc in laboratory water‐only exposures
Chronic toxicity of cadmium, copper, lead, or zinc to White Sturgeon (Acipenser transmontanus) and Rainbow Trout (Oncorhynchus mykiss) was evaluated in water‐only exposures started with newly hatched larvae or about 1‐month‐old juveniles. The 20% effect concentration (EC20) for cadmium from the sturgeon tests was higher than the EC20 from the trout tests, whereas the EC20 for copper, lead, or zinc for the sturgeon were lower than those EC20s for the trout. When the EC20s from the present study were included in compiled toxicity databases for all freshwater species, species mean chronic value (SMCV) for White sturgeon was in a relatively low percentile of the species sensitivity distribution for copper (9th percentile) and in the middle percentile for cadmium (55th percentile), zinc (40th percentile), or lead (50th percentile). However, the SMCV for Rainbow Trout was in a high percentile for copper, lead, or zinc (about 68th to 82nd percentile), but in a low percentile for cadmium (23rd percentile). The trout EC20s for each of the four metals and the sturgeon EC20s for cadmium or lead were above U.S Environmental Protection Agency chronic ambient water quality criterion (AWQC) or Washington State chronic water quality standards (WQS), whereas the sturgeon EC20s for copper or zinc were about equal to or below the chronic AWQC and WQS. In addition, acute 50% effect concentrations (EC50) for copper obtained in the first 4 days of the chronic sturgeon test was below the final acute value used to derive acute AWQC and below acute WQS for copper.