Endocrine disrupting compounds in effluent waters : Chemical analysis to evaluate exposure of fish

Abstract: The aim of this thesis was to investigate if endocrine disruption related to the release of estrogenic and/or androgenic substances via sewage treatment plant and pulp mill effluents is significant in Swedish waters. Chemical analysis of bile fluid in combination with measurement of biomarkers was used for the evaluation of internal exposure and effects in fish.Exposure to estrogenic substances was demonstrated by pronounced induction of the yolk protein precursor vitellogenin in fish exposed in cages downstream of a small domestic Swedish sewage treatment plant. Estrogenic substances identified in bile from the fish included the natural estrogens, the synthetic estrogen ethinylestradiol and some estrogenic phenols. The bile levels of estrogenic substances corresponded well with the plasma levels of vitellogenin. Significant concentrations of the estrogenic substances were also determined in the effluent water, and it was suggested that the level of ethinylestradiol was sufficient to explain a major part of the observed estrogenicity. Low or no induction of vitellogenin was observed in fish when exposed to final effluent from two modern Swedish sewage treatment plants, and it was concluded that a well functioning biological treatment reduces the amounts of estrogenic substances from the sewage water and that slow sand filtration contributes to further reduction. A field survey along the Baltic Sea coast revealed no signs of estrogenic or androgenic disruption in recipients of sewage treatment plants or pulp mills. This is likely due to efficient water treatment and high dilution rates in the recipients. Endocrine disruption might still be of local concern in receiving waters of less treated effluents that have low dilution rates.A sensitive method for determination of estrogenic substances in water was developed, which will make it possible to establish bioconcentration relationships between water and fish, and dose-response relationships with biomarkers in fish.