Occurrence, fate, and risk of the organic pollutants of the surface water watch List in European groundwaters: a review

Groundwater is the main source of freshwater in the European Union, yet freshwaters are polluted by organic contaminants if contaminants are not efficiently removed in wastewater treatment plants. Here we review the occurrence, fate, and risk assessment of organic contaminants included in the surface water watch list of the European groundwater bodies. This list includes 15 compounds: the hormones estrone, 17˗β˗estradiol and 17˗α˗ethinylestradiol; the pesticides methiocarb, metaflumizone, imidacloprid, thiacloprid, thiamethoxam, clothianidin and acetamiprid; and the antibiotics amoxicillin, ciprofloxacin, azithromycin, clarithromycin and erythromycin. We found that while contaminants commonly occur at low levels of few nanograms per L or are not detected in natural waters, there is an increasing number of reports displaying concentrations above 100 ng/L. Surface waters are commonly more contaminated than groundwater, suggesting that contaminants are removed in groundwater aquifers, e.g. by sorption or biodegradation. The estimated risk following water drinking by humans is higher for infants than for adults. Nonetheless, on the average, groundwater consumption does not pose a risk for human health at the reported groundwater concentrations. Risk assessment using fish, plants, algae, and invertebrates shows that only few species are impacted by contaminants, e.g. Americamysis bahia, Mysidopsis bahia, and Daphnia magna by pesticides; and the plant Lemna minor and the algae Microcystis aeruginosa by the antibiotics ciprofloxacin and erythromycin.

This research has been supported through the Grant CEX2018-000794-S funded by MCIN/AEI/https://doi.org/10.13039/501100011033. Anna Jurado thanks the Ministry of Science, Innovation and Universities for funding the project INTEGRATE (Ref: PID2019-107945RJ-I00) under the 2019 call of the "Proyectos de I+D Retos Investigación”. Estanislao Pujades gratefully acknowledges the support received through the grant RYC2020-029225-I funded by MCIN/AEI/https://doi.org/10.13039/501100011033 and by “ESF Investing in your future”, and the Award for Scientific Research into Urban Challenges in the City of Barcelona 2020 (20S08708) from the Barcelona city council. M. Silvia Díaz˗Cruz acknowledges the Generalitat de Catalunya (Water and Soil Quality Unit 2017-SGR-1404) and the EU (LIFE20 ENV/ES/000284—LIFE REMAR project).

Peer reviewed