Estimation of community-wide multi-chemical exposure via water-based chemical mining: Key research gaps drawn from a comprehensive multi-biomarker multi-city dataset

This paper explores the strong potential of chemical mining of wastewater for markers of community-wide intake of wide-ranging harmful chemicals belonging to several usage groups: industrial chemicals, personal care products, pesticides, illicit drugs, lifestyle chemicals and prescription pharmaceuticals as a proxy for multi-chemical community-wide exposure. An estimation of chemical intake in five contrasting town/cities based in the Avon River catchment in the South-West UK was undertaken. High-resolution spatiotemporal pharmaceutical prescription databases were used for system calibration, both in terms of biomarker selection and its correction factor, as well as for the overall system performance evaluation, both spatially and temporality. Only metabolism data accounting for phase two metabolism provided correct estimates of pharma intake. Using parent compounds as XCRs (xenobiotic compounds residue) was found to overestimate exposure due to an inclusion of directly disposed (unused) drugs. Spatiotemporal trends in XC intake were observed as a result of occupational exposure (higher bisphenol A (BPA) intake during weekday), and lifestyle choices (higher cocaine and pyrethroid pesticides intake during weekend). WBE is not intended to estimate individual exposure to chemicals. It can however provide estimates at a community level, and as a result, it has the potential to be developed into an early warning system, a powerful tool for large scale screening studies identifying communities at risk and in need of high resolution individual testing at a localised scale.