Steroid hormones and estrogenic activity in the wastewater outfall and receiving waters of the Chascomus chained shallow lakes system (Argentina)

Natural and synthetic steroid hormones, excreted by humans and farmed animals, have been considered as important sources of environmental endocrine disruptors. A suite of estrogens, androgens and progestogens was measured in the wastewater treatment plant outfall (WWTPO) of Chascomils city (Buenos Aires province, Argentina), and receiving waters located downstream and upstream from the WWTPO, using solid phase extraction and high-performance liquid chromatography mass spectrometry. The following natural hormones were measured: 17 beta-estradiol (E-2), estrone (E-1), estriol (E-3), testosterone (T), 5 alpha-dihydrotestos terone (DHT), progesterone (P), 17-hydroxyprogesterone (17OHP) and the synthetic estrogen 17 alpha-ethinylestradiol (EE2). Also, in order to complement the analytical method, the estrogenic activity in these surface water samples was evaluated using the in vitro transactivation bioassay that measures the estrogen receptor (ER) activity using mammalian cells. All-natural steroid hormones measured, except 170HP, were detected in all analyzed water samples. E-3, E-1, EE2 and DHT were the most abundant and frequently detected. Downstream of the WWTPO, the concentration levels of all compounds decreased reaching low levels at 4500 m from the WWTPO. Upstream, 1500 m from the WWTPO, six out of eight steroid hormones analyzed were detected: DHT, T, P, 170HP, E-3 and E-2. Moreover, water samples from the WWTPO and 200 in downstream from it showed estrogenic activity exceeding that of the EC50 of the E-2 standard curve. In sum, this work demonstrates the presence of sex steroid hormones and estrogenic activity, as measured by an in vitro assay, in superficial waters of the Pampas region. It also suggests the possibility of an unidentified source upstream of the wastewater outfall. (C) 2020 Elsevier B.V. All rights reserved.