Identifying sources and environmental risks of emerging mobile organic pollutants in the urban groundwater of Barcelona (Spain)

Groundwater is a vital yet vulnerable resource, subject to contamination from recharge sources and water system leaks by organic pollutants, including personal care products, pharmaceuticals, sweeteners, and industrial chemicals. Despite recent European regulatory progress with the 2022 amendments to Directive 2006/118/EC, many mobile pollutants remain unregulated. This study identified 129 organic compounds, including very mobile pollutants (vM) derived from pharmaceuticals, industrial chemicals, and tyre wear, across 197 urban water samples from Barcelona city. They comprised stormwater, surface water, untreated sewage, nine groundwater samples influenced by river infiltration, rainwater, sustainable urban drainage systems infiltrates, and 32 other groundwater samples. The results showed higher detection frequencies and concentrations of highly polar pollutants (log Dow < 0). Most of the 129 detected compounds were found across all water types, with 41 occurring in stormwater, groundwater, surface water, and sewage, highlighting their widespread presence in urban waters. The study also assessed pollution sources, finding that sewage system leaks and surface water were the main contributors to groundwater contamination, with runoff-associated contaminants such as industrial compounds becoming more prominent as distance from the river increased. The environmental risk assessment highlighted significant risks from pharmaceuticals like atorvastatin, ciprofloxacin, and iopamidol, as well as melamine, showing moderate environmental risk. These findings emphasize the need for continued monitoring to better understand the threats posed by these pollutants to groundwater quality. • Detection of 129 mobile pollutants in 197 samples from six urban water types • High detection frequency of highly polar compounds in all water matrices • High detection rates for industrial chemicals, pharmaceuticals, and sweeteners • Pollution sources reveal significant impact on urban groundwater pollution. • Elevated environmental risk of atorvastatin, ciprofloxacin, and iopamidol