A Simple Risk Assesment Method for Continental Waters, Based on Screening Contaminants of Emerging Concern

Abstract

With the aim to build a simple alert system that may be of extended use, a screening for contaminants of emerging concern (CECs) is carried out in the Mero-Barcés hydrographic watershed, in Cecebre, A Coruña, NW Spain, which feeds the reservoir that supplies drinking water to ≈400 000 inhabitants in the area. Water samples are collected for five years (2015–2019) at six different sampling points, to assess the presence and potential risk of CECs, including some widely used drugs: clofibric acid, paracetamol carbamazepine, diclofenac, ibuprofen, ofloxacin, ketoprofen, and sotalol; an alkaloid: caffeine; synthetic flavourings: galaxolide and tonalide; and a plasticiser: bisphenol A. The most abundant CECs occurring are ibuprofen (>2µg L⁻¹), diclofenac, caffeine, and galaxolide. Samples of treated drinking water show a certain degree of CECs abatement. The presence of nonpolar substances, banned in the EU nowadays, is confirmed. A snapshot of sediments is sampled in 2018–2019, and PAHs and PCBs are quantified, the former being mainly of pyrogenic origin. Based on known properties of quantifiable substances, a traffic-light system is developed for risk assessment of the state of continental waters, a strategy that may be useful for decission-makers to implement environmental remediation policies