Developing meaningful water-energy-food-environment (WEFE) nexus indicators with stakeholders: An Upper White Nile case study.

The Upper White Nile (UWN) basin plays a critical role in supporting essential ecosystem services and the livelihoods of millions of people in East Africa. The basin has been exposed to tremendous environmental pressures following high population growth, urbanisation, and land use change, all of which are compounded by the threats posed by climate change and insufficient financial and human resources. The water-energy-food-environment (WEFE) nexus provides a framework to assess solution options towards sustainable development by minimising the trade-offs between water, energy, and food resources. However, the majority of existing WEFE nexus indicators and tools tend to be developed without consideration of practitioners at the local level, thus constraining the practical application within real-world contexts. To try to address this gap and operationalise the WEFE nexus, we examined how local stakeholders frame the most pressing WEFE nexus challenges within the UWN basin, how these can be represented as indicators, and how existing WEFE nexus modelling tools could address this. The findings highlight the importance of declining water quality and aquatic ecosystem health as a result of deforestation and increasing agricultural intensity, with stakeholders expressing concerns for the uncertain impacts from climate change. Furthermore, a review of current WEFE nexus modelling tools reveals how they tend to be insufficient in addressing the most pressing environmental challenges within the basin, with a significant gap regarding the inclusion of water quality and aquatic ecosystem indicators. Subsequently, these findings are combined in order to guide the development of WEFE nexus indicators that have the potential to spatially model the trade-offs within the WEFE nexus in the UWN basin under climate change scenarios. This work provides an example of how incorporating local stakeholder's values and concerns can contribute to the development of meaningful indicators, that are fit-for-purpose and respond to the actual local needs.

Evaluation of formation and health risks of disinfection by-products in drinking water supply of Ggaba waterworks, Kampala, Uganda.

In developing countries, the evaluation of disinfection by-products in drinking water has been neglected because most water utility companies focus on microbial elimination. As a result, this study aimed at evaluating trihalomethane formation, the relation between water quality parameters and trihalomethane formation, and the estimation of the associated potential health risks in drinking water. The headspace purge and trap coupled with a gas chromatography-mass spectrometry technique was used to quantify trihalomethane. The concentrations of trihalomethane found in the water were within the National Water and Sewerage Corporation, World Health Organization guidelines, and the United States Environmental Protection Agency standards. Total organic carbon, ultraviolet absorbance at 254 nm, bromide concentration, and the temperature had a positive and significant correlation, pH had a positive but non-significant correlation, while the residual chlorine had a negative but significant correlation with trihalomethane formation. The potential health risk using the WHO index was 0.4, indicating no noncarcinogenic risk to human health in the study area. The lifetime carcinogenic risks of trihalomethane due to oral ingestion, dermal, and inhalation were 2.5×10-5, 9.1×10-6, and 8.3×10-6 for females and 2.4×10-5, 1×10-5, and 7.9×10-6 for males, and the values were within the USEPA acceptable low-risk range of 1×10-6

Daily variation of heavy metal contamination and its potential sources along the major urban wastewater channel in Kampala, Uganda.

Heavy metal pollution from untreated industrial wastewater has become a major concern to the environment and public health in many rapidly growing cities in low-income countries. Previous studies on heavy metals of urban wastewater systems have focused on long-term (weekly or seasonal) variations, while only few studies investigated short-term (daily) variation to capture potential bulk discharges. To monitor and enforce wastewater discharge regulations and reduce industrial pollution, a better understanding of the short-term variation of these pollutants and industrial discharge practices is needed. The aim of this study is to assess the daily variation of heavy metals and physicochemical parameters along the major urban wastewater system in Kampala, Uganda. Over 1 week, daily water samples were collected at 16 locations and analyzed for lead (Pb), mercury (Hg), copper (Cu), and chromium (Cr) and a range of physicochemical parameters. Additionally, 25 key informant interviews with industries were administered to investigate their potential to contaminate the environment. Among 78 water samples, 29 exceeded the national standards for Pb (> 0.1 mg/L) and one for Hg (> 0.01 mg/L). High daily variation and peak concentrations were detected which are likely due to industries retaining their effluents and discharging them irregularly. Although 24 industries used heavy metals in their manufacturing processes and are likely to discharge heavy metals, only ten industries had a wastewater treatment system in place. Our results show that repeated measurements of heavy metals over short time intervals are needed to capture their high daily variation in an urban wastewater system. Furthermore, there is an urgent need to register industries and to assess their effluent composition in order to select appropriate wastewater management measures.