Behavior and occurrence of estrogens in municipal sewage treatment plants — I. Investigations in Germany, Canada and Brazil

Abstract

The developed method enables the quantification of estrogens in sewage samples down to 1 ng/l and in river water down to 0.5 ng/l. Mean recoveries of the analytes in ground water after SPE extraction, clean-up and derivatization generally exceeded 75%. The determined R.S.D. varied from 0 to 14% at a spiking level of 0.05 μg/l. Even in the raw influent and the final effluent from municipal STPs the mean recoveries of estrogens were mostly above 70%. Using this method the behavior and occurrence of natural estrogens and synthetic contraceptives in municipal sewage treatment plants (STP) were investigated in German and Canadian facilities. In the sewage of a German municipal STP close to Frankfurt/Main 17β-estradiol and estrone were determined, with mean concentrations of 0.015 μg/l and 0.027 μg/l, respectively. In two investigated municipal STPs, 17β-estradiol and 16α-hydroxyestrone were eliminated with a higher efficiency than 17α-ethinylestradiol and estrone. In Canadian and German STP discharges estrone, 17β-estradiol, 17α-ethinylestradiol and 16α-hydroxyestrone were frequently detected within the lower ng/l-range. A maximum concentration was found for estrone with 70 ng/l. In 15 investigated German rivers and streams only estrone was present with a maximum concentration of 1.6 ng/l.

Introduction

Many effects observed in the aquatic environment concerning the reproductive system, for instance the feminisation of male fish within sewage treatment plant (STP) effluents, are attributed to the presence of endocrine disrupters (Purdom et al., 1994, Sumpter and Jobling, 1995). The individual compounds which are responsible for these harmful effects are currently unknown, whereas many substances like nonylphenols, phthalic esters, PCBs, dioxins, phytoestrogens and human estrogens are suspected to influence the hormonal system (Roembke et al., 1996). Recently, it has been hypothesized that the statistically derived decrease in sperm counts over the last decades, increasing incidents of testicular cancer and other disorders regarding male infertility may be caused by the intake of estrogens via food or drinking water (Sharpe and Skakkebaek, 1993). However, there is a lack of data about the exposure of the aquatic environment as well as food and drinking water to estrogens, although the first results had already been published in 1970 (Tabak and Bunch, 1970).

Several drugs are used in medicine to influence the endocrine (hormonal) system. One well known example are the contraceptives utilized as ingredients of birth control pills. In general, municipal sewage and therefore excreted human pharmaceuticals and natural hormones have to pass through an STP prior to entering rivers or streams. In the literature little information is available dealing with the behavior of natural and synthetic estrogens in STPs (Norpoth et al., 1973, Tabak et al., 1981, Shore et al., 1993).

A potential contamination of soil and ground water may be caused by the application of digested sludge from municipal STP on agricultural fields. Additionally, transport of hormones via bank filtration from contaminated surface water into ground water, as well as the infiltration of waste waters directly from leakage in drains is possible. However, the principal pathway should lead to the municipal STP and after incomplete removal release into the receiving waters. In order to evaluate the potential risk of the endocrine disrupting, the occurrence of individual compounds needs to be documented. In vitro test systems like competitive ligand binding assays (e.g. yeast cell assay) or cell proliferation assays (e.g. E-screen assay) exhibited at least two orders of magnitude higher estrogenic activity for 17β-estradiol than for other potential endocrine disrupters like nonylphenols or PCBs (Jobling and Sumpter, 1993, Soto et al., 1994, Soto et al., 1995, Jobling et al., 1995, Arnold et al., 1996a, Arnold et al., 1996b, Zacharewski, 1997). Therefore, a precise quantitation of natural estrogens and contraceptives in the STP effluents is essential for a risk assessment regarding endocrine disrupting effects in the aquatic environment.