Wastewater analysis of chemical markers of public health concern at small spatial scales: A scoping review

Wastewater analysis is a promising approach to obtaining population-based health information. It has proven useful for different applications, including monitoring illicit drugs or assessing population-level exposure to chemicals. Studies have often analysed samples from wastewater treatment plants, which does not allow for small-scale intra-sewershed differentiations needed for a detailed assessment of the target population. The small-scale approach offers various benefits, but a comprehensive review of its application to chemicals has not yet been undertaken. This scoping review aims to provide a detailed overview of the current knowledge on wastewater analysis of chemical markers of public health concern, including methodological aspects. We conducted a systematic database search for peer-reviewed articles. Data were analysed using quantitative summaries and qualitative narrative synthesis. Out of 2283 articles, 99 studies were included. Most were published after 2010. The studies analysed wastewater from different settings, with a focus on points of interest such as healthcare and education facilities, and few studies at neighbourhood-level. Pharmaceuticals, industrial and environmental chemicals and stimulants were most commonly investigated. While most studies reported their sampling mode, few provided detailed specifications. Small-scale sampling sites were characterized to varying degrees, with many studies reporting only a single characterization criterion. Advancing the area of research of small-scale wastewater analysis requires consistent and transparent methodological reporting and a more detailed sampling site characterization. Wastewater analysis of chemical markers of public health concern at small spatial scales shows great potential for further public health applications, including occupational health and monitoring chemical exposure in schools.