Estrogenic activity of wastewater,bottled waters and tap water in Finland as assessed by a yeast bio-reporter assay

Abstract

Aims: Environmental pollutants appearing in wastewater, bottled mineral water, tap water, and bottled drinking water are potential, but yet poorly characterized, sources of human exposure to endocrine disrupting chemicals globally. Here, we investigated the current situation in the most densely populated region in Finland. Methods: Influent and effluent bi-monthly samples from a major wastewater treatment plant in Helsinki were obtained over a preceding 2-year period at two time-points (in 2011 and 2014). Equivalent samples from a household water purification plant (located in the same region) were also analyzed, together with various brands of bottled still and mineral water as well as tap water from residential buildings. Samples were obtained in one liter sterile containers, extracted by solid-phase extraction method, and their estrogenic potential determined by a yeast bioluminescent assay. Results: The estrogenic activities of influent samples from the wastewater treatment plant in Helsinki were generally low (from less than limit of detection to 0.7 ng/L estrogen equivalent quantities (EEQ)), except in March and August 2011, when relatively high levels (14.0 and 7.8 ng/L EEQ, respectively) were obtained. Meanwhile, no estrogenic activity was recorded in any of the treated effluent samples from the wastewater treatment plant, influent and effluent samples from the drinking water plant, as well as tap water, bottled still, and mineral waters. Conclusions: These findings indicate that the purification method applied in Helsinki wastewater treatment plant, activated sludge with mechanical, chemical and biological purification steps, is effective in reducing estrogenic activity, and that tap or bottled waters are not a significant source of these compounds to the population in this region.