Clarity tubes as effective citizen science tools for monitoring wastewater treatment works and rivers

Abstract Improved freshwater resource management requires the implementation of widespread, effective, and timely water quality monitoring. Conventional monitoring methods are often inhibited by financial, infrastructural, and human capacity limitations, especially in developing regions. This study aimed to validate the citizen-scientist-operated transparency or clarity tube (hereafter “clarity tube”) for measuring water clarity as a proxy for total suspended solids (TSS) concentration, a critical quality metric in river systems and wastewater treatment works (WWTW) effluent in Southern Africa. Clarity tubes provided a relatively accurate and precise proxy for TSS in riverine lotic systems and WWTW effluent, revealing significant inverse log-linear relationships between clarity and TSS with r2 = 0.715 and 0.503, respectively. We demonstrate that clarity-derived estimates of TSS concentration (TSScde) can be used to estimate WWTW compliance with WWTW effluent TSS concentration regulations. The measurements can then be used to engage with WWTW management, potentially affecting WWTW performance. Overall, these findings demonstrate the usefulness of clarity tubes as low-cost, accessible, and easy-to-use citizen science tools for high spatial and temporal resolution water quality monitoring, not only in rivers in Southern Africa but also in WWTW effluent for estimating compliance, with strong global relevance to the sustainable development goals (SDGs). Integr Environ Assess Manag 2024;20:1463–1472. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points Clarity tubes provide a relatively accurate and precise proxy for total suspended solids (TSS) in riverine lotic systems and wastewater treatment works (WWTW) effluent, revealing significant inverse log-linear relationships between clarity and TSS. Clarity-derived estimates of TSS concentration (TSScde) can be used to estimate WWTW compliance with WWTW effluent TSS concentration regulations, which can then be used to engage with WWTW management, potentially affecting WWTW performance. These findings demonstrate the usefulness of clarity tubes as low-cost, accessible, and easy-to-use citizen science tools for high spatial and temporal resolution water quality monitoring in rivers in Southern Africa and in WWTW effluent for estimating compliance. Using clarity tubes for river and WWTW monitoring is a decisive step toward achieving significant progress in meeting sustainable development goal (SDG) 6 for ensuring safe access to water and sanitation for all, specifically SDG 6.3.2 and SDG 6b, by involving communities in water and sanitation monitoring and management.