Detection of Estrogen- and Dioxin-like Activity in Pulp and Paper Mill Black Liquor and Effluent Using in vitro Recombinant Receptor/Reporter Gene Assays

Methanol extracts of pulp and paper mill effluent (MF) and black liquor, a recovered by-product, were examined by bioassays for dioxin-like, estrogenic and anti-estrogenic activities. Black liquor was estimated as containing 4 ppb estrogen equivalents using MCF-7 cells transiently transfected with a Gal4-estrogen receptor guchimeri construct and a Gal4-regulated luciferase reporter gene. MF had negligible estrogenic activity. A dioxin response element-regulated luciferase reporter gene (pGudLuc 1.1) transiently transfected into Hepa1c1c7 wild-type cells showed a dose-dependent increase in luciferase activity following treatment with MF, black liquor and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Black liquor and MF contained 10 and 20 ppb TCDD equivalents. MF also had significant Ah receptor-mediated anti-estrogenic activity. The effects of MF on fish could be due to Ah receptor and ER ligands not detected by chemical analysis. There are 78 references.