Occurrence of persistent and mobile chemicals and other contaminants of emerging concern in Spanish and Portuguese wastewater treatment plants, transnational river basins and coastal water

This work investigated, during one year, the occurrence and fate of 52 contaminants of emerging concern (CECs) in transnational river basins and coastal areas of the North of Portugal and Galicia (NW Spain) and the wastewater treat-ment plants (WWTPs) discharging on these environments. The different CECs investigated included pharmaceuticals, personal care products, industrial chemicals, among others, of which ca. 90 % would fulfill the persistence, mobility and toxicity criteria proposed by the German Environmental Agency. The results showed the ubiquitous presence of these CECs and an incomplete removal of over 60 % of them with current conventional WWTPs. These findings high-light the requirement of a prominent and coordinated upgrade of WWTP treatments in order to meet the future European Union regulations on urban wastewater treatment and surface water quality. In fact, even some compounds exhibiting high removals, such as caffeine or xylene sulfonate, were frequently detected in river and estuarine waters at the high ng L-1 level. Thus, our preliminary risk assessment study concluded that 18 of the CECs presented a potential risk for the environment, being caffeine, sulpiride, perfluorooctanoic acid (PFOA), diclofenac, fipronil and perfluorobutanoic acid (PFBA) the most concerning ones. Yet, additional toxicity data as well as a more robust infor-mation on persistence and mobility of CECs are necessary for better estimating the magnitude of the problem and im-prove risk assessment. As an example, in the case of the antidiabetic metformin, recent research has revealed toxicity for model fish species at concentration levels below those found in 40 % of the river water samples analyzed in this work.

Automated summary

This study examined the occurrence and fate of 52 emerging contaminants in transnational river basins, coastal areas, and wastewater treatment plants in Portugal and Spain. The results showed that these contaminants were widely present and were only partially removed by conventional treatment processes. These findings highlight the need for significant upgrades and coordination of wastewater treatment plants to meet future EU regulations.