Contaminants of emerging concern in drinking water: Quality assessment by combining chemical and biological analysis

Abstract

Drinking water quality is a priority issue of the environmental policy agenda, however regulation on Contaminants of Emerging Concern (CECs) is limited. A proposal to revise the Drinking Water Directive has recently been approved (EU Council 2020), which updates the quality standards and introduces the watch list mechanism, including for the first time endocrine disruptors and pharmaceuticals. The purpose of this study was to evaluate the occurrence of selected CECs in surface water at the entrance of drinking water treatment plants (DWTPs) and in treated water, ready for distribution in the network. Samples were collected at three different DWTPs (Italy) and CECs assessed by LC-MS/MS were the following: bisphenol A (BPA), nonylphenol (NP), octylphenol, perfluorooctanesulfonic and perfluorooctanoic acids (PFOS and PFOA), atenolol, caffeine (CFF), carbamazepine (CBZ), estrone, 17-β-estradiol, 17-α-ethinyl estradiol, diclofenac, and ibuprofen. In addition, biological analyses were performed to ascertain cumulative estrogenic and/or genotoxic potential of the samples. CFF, NP, PFOA, BPA, and CBZ were the most frequently detected contaminants, found in treated water in the following ranges: CFF 12.47-66.33 ng/L, NP 7.90-53.62 ng/L, PFOA <LOQ-12.66, ng/L, BPA <LOQ-6.27 ng/L, and CBZ <LOQ-1.20 ng/L. While treatments were generally efficacious in reducing BPA, CFF and CBZ, they were sometimes ineffective for NP and PFOA. According to the low concentrations and/or regulation limit for each single contaminant, the water analyzed met the criteria of good quality. No estrogenic or genotoxic activities were induced by the water assessed, with the exception of one sample. It has been suggested that drinking water may not represent a significant source of human exposure to CECs, however co-occurrence of different compounds may lead to additive/synergistic interactions causing unexpected effects on human health and the environment, and deserve implementation of strategies for detection and removal.

Keywords: Contaminants of emerging concern; Drinking water; E-screen assay; LC-MS/MS; Micronuclei test.