Abstract
Micropollutants such as heavy metals or pesticides from untreated industrial or agro-industrial wastewater has become a major concern to the environment and public health around many rapidly growing cities in low-income countries. To develop reasonable context-specific wastewater discharge regulations and ultimately reduce micropollutants a better understanding of the level of contamination and discharge practices is needed. We present findings of three studies around wastewater management and reuse with a focus on micropollutants subsequently published by the presenting author between 2013 and 2019 from Kampala, Uganda. The three papers reflect critically on sustainable management of micropollutants along wastewater systems in low-income countries while providing a link to Sanitation Safety Planning and the Sustainable Development Goal (SDG) 6 (clean water and sanitation) and SDG 3 (good health and well-being).
Keywords: Industrial wastewater management and reuse; micropollutants; low-income countries
Background
Low- and middle-income countries (LMICs) in Africa, Asia and Latin America have experienced fast paced population growth and urbanization over the past decades (United Nations 2014). Around these rapidly growing cities in LMICs appropriate treatment facilities for emerging micropollutants, which are released with industrial effluents, such as heavy metals, pharmaceuticals or pesticides, are often missing (Weiss et al. 2016). Consequently, contaminated industrial and agro-industrial wastewaters are released into the environment without appropriate treatment and may lead to considerable environmental and public health risks.
In Kampala, the capital city of Uganda, several efforts have been conducted to describe the consequences of microbial water contamination (e.g., for bacteria and viruses) using quantitative microbial risk assessments (Fuhrimann, Winkler, Stalder, et al. 2016; Katukiza et al. 2013) or for parasitic infections using epidemiolocal surveys (Fuhrimann, Winkler, Kabatereine, et al. 2016) and reduce their disease burden while developing improved stepwise management plans (e.g., using a sanitation safety planning approach) (Winkler et al. 2017). However, alongside the successes to manage risks form microbial pollution little is understood about the environmental and public health burden due to micropollutants discharged by industrial and agro-industrial sources.
The aim of this paper is to provide a critical overview of the management challenges and potential environmental and public health risks due to contamination with micropollutants along the major wastewater chain in Kampala, Uganda.
Method
Study design
We present findings over three studies around wastewater management with a focus on micropollutants subsequently published by the presenting author between 2013 and 2019 from Kampala, Uganda. In addition, we reflect critically on sustainable management of micropollutants along wastewater systems in low-income countries while providing a link to Sanitation Safety Planning and the Sustainable Development Goal (SDG) 6 (clean water and sanitation) and SDG 3 (good health and well-being) (United Nations 2015).
Study area
The studies were conducted in Kampala which has an estimated population of 1.5 million people according to the 2014 census (Uganda bureau of statistics 2010). This study area focuses on the catchment area of the Nakivubo Channel. The channel stretches over 12.3 km through the whole city transporting industrial and domestic wastewater including the effluents of the wastewater treatment plant. The inner Murchison Bay is important for local fisheries and the source of Kampala’s drinking water is located about 4 km from the mouth of the Nakivubo Channel. Industries active in the Nakivubo Channel catchment area include manufacturers of paints, plastics, metal products, textiles, as well as warehouses and garages.
Results
Paper I: Health risk assessment along the wastewater and faecal sludge management and reuse chain of Kampala, Uganda: a visualization (Fuhrimann et al. 2014)
We visualise in the form of a short movie an assessment of health risks along the major wastewater channel in Kampala, Uganda. The visualization brings to bear the context of wastewater reuse activities in the Nakivubo wetlands and emphasises interconnections to disease transmission pathways and bio-accumulation of heavy metals along the food chain. The contextual features are complemented with findings from environmental sampling and a epidemiological survey in exposure groups.
Paper II: Microbial and chemical contamination of water, sediment and soil in the Nakivubo wetland area in Kampala, Uganda (Fuhrimann et al. 2015)
We assessed chemical and microbial pollutants in 23 sentinel sites along the wastewater and faecal sludge management and reuse chain of Kampala, Uganda. Water, sediment and soil samples and
edible plants (yams and sugar cane) were tested for heavy metals. Mean concentrations of iron (Fe), copper (Cu) and cadmium (Cd) were 21.5, 3.3 and 0.14 mg/L, respectively. In soil samples, we found a mean lead (Pb) concentration of 132.7 mg/L. In yams, concentrations of Cd, chromium (Cr) and Pb were 4.4, 4.0 and 0.2 mg/L while the respective concentrations in sugar cane were 8.4, 4.3 and 0.2 mg/L. Pb in soil, and Cd, Cr and Pb in the plants were above national thresholds. We conclude that there is considerable environmental pollution in the Nakivubo wetland and the Lake Victoria ecosystem in Kampala. Our findings have important public health implications, and we suggest that a system of sentinel surveillance is being implemented that, in turn, can guide adequate responses.
Paper III: Daily variation of heavy metal contamination and its potential sources along the Nakivubo Channel in Kampala, Uganda (Dietler et al. 2019)
We assessed 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 analysed 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.
Discussion and conclusions
We showed over the series of three paper and four years of research the challenges of the wastewater management and reuse system with micropollutants in Kampala. Our research helped to establish a “Pollution Task Force” in Kampala consisting of the most important public stakeholders and private industries. Their aim is to reduce industrial pollution by enforcing the discharge regulations and to create public awareness for sustainable production (www.kcca.go.ug/pollution-control-task-force).
Overall, these continued research efforts and dialogues with key stakeholders in the wastewater sector in Kampala is a practical example on how to step-by-step establish a thorough understanding of a wastewater system. This is important to i) better understand potential environmental and public health problems of emerging micropollutants; ii) prioritize management efforts in the light of the often also high disease burden due to microbial pollution around cities in low-income countries; and iii) which contributes to the achievement SDG 3 and SDG 6.
| Period | 2 Dec 2019 |
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| Event title | IWA Water and Development Congress & Exhibition 2019 |
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| Event type | Conference |
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| Location | Colombo, Sri LankaShow on map |
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| Degree of Recognition | International |
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- Water
- Heavy metals
- Uganda
- SDG 3