INDUCTION OF EROD ACTIVITY IN HEPA-1 MOUSE HEPATOMA-CELLS AND ESTROGENICITY IN MCF-7 HUMAN BREAST-CANCER CELLS BY EXTRACTS OF PULP-MILL EFFLUENTS, SLUDGE, AND SEDIMENT EXPOSED TO EFFLUENTS

Extracts of effluents and sludges from the primary and secondary clari fiers of an activated sludge treatment plant at a Finnish bleached kra ft pulp and paper mill were analyzed in two cell bioassays. Total diox in-like activities were determined by measuring the induction of ethox yresorufin-O-deethylase (EROD) activity in Hepa-l mouse hepatoma cells . Estrogenicity was studied by measuring luciferase activity in MCF-7 ERE-luc, which are MCF-7 human breast cancer cells stably transfected with an estrogen-responsive element linked to a luciferase promoter. S ediments collected near the pulp mill and from other sites in Lake Sai maa as well as fillets of whitefish exposed to effluents were examined and EROD activity was determined for complex mixtures of compounds ex tractable with dichloromethane (DCM) from the pulp mill effluent or co mpounds collected by semipermeable membrane devices (SPMDs) from the s ame effluent. Extracts of effluents, particulates, SPMDs, and sludges all caused measurable EROD induction. Because the induction potencies of the total DCM extract and the fraction of neutral compounds were si milar, it was concluded that most of the EROD induction in pulp mill e ffluents was due to neutral compounds. Sediment collected from the vic inity of the pulp mill had greater EROD-inducing potency compared to t hat of the control sites from the same lake. Induction of EROD potenci es of muscle extracts of whitefish exposed to diluted effluents were n ot significantly greater than those of control fish exposed to dilutio n water only. All extracts contained some estrogen agonist activity wh en tested in the MCF-7 bioassay.