A community-guided approach to monitoring contaminants of emerging concern in freshwater systems using passive samplers.

Chemical pollution in the aquatic environment is a global issue, representing a threat to human and environmental health, especially for unregulated contaminants of emerging concern (CECs). Identifying and prioritising pollution sources requires high spatio-temporal resolution data and strategic site selection; here, local knowledge provides valuable insight. This study evaluated a community-guided approach for monitoring CECs in freshwater systems using a miniaturised 3D-printed passive sampler device (3D-PSD). Seventeen citizen scientists from Sheffield, Norwich, and London (England) selected sites along their local rivers and were trained to deploy 3D-PSDs and collect water samples. A total of 51 CECs were quantified in the water and passive sampler extracts, with ketamine, lidocaine, tramadol, and venlafaxine occurring in over 50% of samples. All compounds were present below the medium-risk threshold. Results were shared via an online meeting and a public-facing report. Participants highlighted the importance of rivers and other blue-green spaces in their daily lives and reported spending up to four hours at their local rivers per visit. They identified key areas for improving the field deployment procedure and the data collection system. This work demonstrates the applicability of the 3D-PSD to large-scale citizen science and other community engagement projects for freshwater monitoring.