Carcinogenicity and mutagenicity testing of extracts from bleached kraft mill effluent

Mutagenicity and carcinogenicity assays were used to determine whether bleached kraft mill effluents (BKME) have the potential to be carcinogenic to fish. BKME extracts were prepared by adsorption of non-polar and moderately polar effluent components onto XAD-4 and XAD-7 resins, respectively. Mutagenic activity was detected in both the XAD-7 and XAD-4 extracts using the Salmonella fluctuation assay. The BKME extracts did not induce hepatic neoplasms in a carcinogenicity assay with rainbow trout (Oncorhynchus mykiss), but there was some evidence of promotional activity by XAD-4 extracts in fish previously exposed to aflatoxin B1. These data indicate that BKME is not a potent liver carcinogen in fish.