2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in extracts of Baltic white-tailed sea eagles
Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin-(TCDD) equivalents were measured in extracts of Baltic white-tailed sea eagle tissues. Extracts of salmon, ringed seal, and grey seal were analyzed as other predatory species of the same area. Concentrations in eagle and seal tissues were greater than those in salmon. Concentrations of TCDD equivalents (TCDD-EQs) determined by the H4IIE bioassay were compared with toxic equivalents (TEQs) derived from instrumental chemical analyses in fractions containing polychlorinated dibenzo-P-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) or coplanar polychlorinated biphenyls (PCBs). Toxic equivalents were calculated by use of an additive mod…
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 clarifiers of an activated sludge treatment plant at a Finnish bleached kraft pulp and paper mill were analyzed in two cell bioassays. Total dioxin-like activities were determined by measuring the induction of ethoxyresorufin-O-deethylase (EROD) activity in Hepa-1 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. Sediments collected near the pulp mill and from other sites in Lake Saimaa as well as fillets of whitefish exposed to effluents were examine…
Ethoxyresorufin-O-deethylase induction potency of polychlorinated diphenyl ethers in H4IIE rat hepatoma cells
Polychlorinated diphenyl ethers (PCDEs) are structurally similar to polychlorinated biphenyls (PCBs), and some PCDE congeners have been reported to cause toxic responses similar to those caused by some of the non-ortho-substituted PCBs, which are mediated by the aryl hydrocarbon receptor (AhR). Twenty-nine PCDEs were tested for their potency as AhR agonists relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) by measuring their ability to induce the cytochrome P-450 1A1-associated enzyme activity, ethoxyresorufin-O-deethylase (EROD), in the H4IIE rat hepatoma cell bioassay. All PCDE congeners tested were found to be inactive as EROD inducers except for PCDE 156, which was a weak E…