Daily variation of heavy metal contamination and its potential sources along the major urban wastewater channel in Kampala, Uganda
- 35 Downloads
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.
KeywordsEnvironmental pollution Industrial wastewater Lead Mercury Chromium Nakivubo Channel
This work was funded by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH (grant number 81194938). We want to thank the German Development Cooperation (GIZ) for their thrust and support for this study.
Special thanks go to Catherine, Sammy, and Simon for their diligent work in the field and to Dean for his flexibility with the analysis of the samples. Further, we want to express our gratitude to all people from the Directorate of Water Resources Management (DWRM), the National Water and Sewerage Corporation (NWSC), and the Kampala Capital City Authority (KCCA) for our fruitful interactions.
SF, DD, and GC initiated and elaborated the design of the study in interaction with partners in Uganda. DD, SF, and EM conducted the water sampling in the field in collaboration with MB and AA. EM mapped industries and conducted the key informant interviews. DD and SF undertook data analysis and wrote the manuscript. All the co-authors provided inputs to the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare no personal, financial, or other conflict of interest.
- APHA, AWWA, WEF. (1995). Standard methods for the examination of water and wastewater. Washington DC: American Public Health Association/American Water Works Association/Water Environment Federation.Google Scholar
- Baran, A., & Antonkiewicz, J. (2017). Phytotoxicity and extractability of heavy metals from industrial wastes. Environment Protection Engineering, 43, 143–155.Google Scholar
- Barrenha, P. I. I., Tanaka, M. O., Hanai, F. Y., Pantano, G., Moraes, G. H., Xavier, C., Awan, A. T., Grosseli, G. M., Fadini, P. S., & Mozeto, A. A. (2018). Multivariate analyses of the effect of an urban wastewater treatment plant on spatial and temporal variation of water quality and nutrient distribution of a tropical mid-order river. Environmental Monitoring and Assessment, 190, 43. https://doi.org/10.1007/s10661-017-6386-4.CrossRefGoogle Scholar
- Calamari, D., & Naeve, H. (Eds.). (1994). Review of pollution in the African aquatic environment. Rome: Food and Agriculture Organization of the United Nations, Committee for Inland Fisheries of Africa (CIFA).Google Scholar
- Camacho-Muñoz, D., Martín, J., Santos, J. L., Aparicio, I., & Alonso, E. (2014). Occurrence of surfactants in wastewater: Hourly and seasonal variations in urban and industrial wastewaters from Seville (Southern Spain). The Science of the Total Environment, 468–469, 977–984. https://doi.org/10.1016/j.scitotenv.2013.09.020.CrossRefGoogle Scholar
- Dafforn, K. A., Simpson, S. L., Kelaher, B. P., Clark, G. F., Komyakova, V., Wong, C. K. C., & Johnston, E. L. (2012). The challenge of choosing environmental indicators of anthropogenic impacts in estuaries. Environmental Pollution, 163, 207–217. https://doi.org/10.1016/j.envpol.2011.12.029.CrossRefGoogle Scholar
- Deycard, V. N., Schäfer, J., Blanc, G., Coynel, A., Petit, J. C. J., Lanceleur, L., Dutruch, L., Bossy, C., & Ventura, A. (2014). Contributions and potential impacts of seven priority substances (As, Cd, Cu, Cr, Ni, Pb, and Zn) to a major European Estuary (Gironde Estuary, France) from urban wastewater. Marine Chemistry, 167, 123–134. https://doi.org/10.1016/j.marchem.2014.05.005.CrossRefGoogle Scholar
- Dhokpande, S. R., & Kaware, J. P. (2013). Biological methods for heavy metal removal—a review. International Journal of Engineering Science and Innovative Technology, 2, 304–309.Google Scholar
- Fuhrimann, S., Stalder, M., Winkler, M. S., Niwagaba, C. B., Babu, M., Masaba, G., Kabatereine, N. B., Halage, A. A., Schneeberger, P. H. H., Utzinger, J., & Cissé, G. (2015). Microbial and chemical contamination of water, sediment and soil in the Nakivubo wetland area in Kampala, Uganda. Environmental Monitoring and Assessment, 187, 475. https://doi.org/10.1007/s10661-015-4689-x.CrossRefGoogle Scholar
- Kayima, J., Kyakula, M., Komakech, W., & Echimu, S. P. (2008). A study of the degree of pollution in Nakivubo Channel, Kampala, Uganda. Journal of Applied Sciences and Environmental Management, 12.Google Scholar
- Khan, A., Khan, S., Khan, M. A., Qamar, Z., & Waqas, M. (2015). The uptake and bioaccumulation of heavy metals by food plants, their effects on plants nutrients, and associated health risk: a review. Environmental Science and Pollution Research, 22, 13772–13799. https://doi.org/10.1007/s11356-015-4881-0.CrossRefGoogle Scholar
- Mbabazi, J., Kwetegyeka, J., Ntale, M., & Wasswa, J. (2010). Ineffectiveness of Nakivubo wetland in filtering out heavy metals from untreated Kampala urban effluent prior to discharge into Lake Victoria, Uganda. African Journal of Agricultural Research, 5, 3431–3439.Google Scholar
- Meghea, I., Mihai, M., & Craciun, E. (2012). Statistical control of mercury in surface water of Bucharest. Journal of Environmental Protection and Ecology, 13, 1242–1252.Google Scholar
- Muwanga, A., & Barifaijo, E. (2006). Impact of industrial activities on heavy metal loading and their physico-chemical effects on wetlands of lake Victoria basin (Uganda). African Journal of Science and Technology, 7. https://doi.org/10.4314/ajst.v7i1.55197.
- NEMA. (1999). Standards for discharge of effluent into water or on land. Kampala: National Environment Management Authority.Google Scholar
- Sekabira, K., Origa, H. O., Basamba, T. A., Mutumba, G., & Kakudidi, E. (2010a). Assessment of heavy metal pollution in the urban stream sediments and its tributaries. International journal of Environmental Science and Technology, 7, 435–446. https://doi.org/10.1007/BF03326153.CrossRefGoogle Scholar
- Stewart, M., Cameron, M., McMurtry, M., Sander, S. G., Benedict, B., Graham, L., Hosie, M., & Green, T. (2016). Development of passive sampling devices for bioavailable contaminants of current and emerging concern: Waitemata Harbour case study. New Zealand Journal of Marine and Freshwater Research, 50, 526–548.CrossRefGoogle Scholar
- Tilley, E., Ulrich, L., Lüthi, C., et al. (2014). Compendium of sanitation systems and technologies. Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf.Google Scholar
- UBOS. (2016). The national population and housing census 2014—main report. Kampala: Uganda Bureau of Statistics.Google Scholar
- UBOS. (2017). 2016 statistical abstract. Kampala: Uganda Bureau of Statistics.Google Scholar
- UN. (2014). World urbanization prospects: the 2014 Revision. New York: United Nations, Department of Economic and Social Affairs, Population Division.Google Scholar
- UN. (2017). World population prospects: the 2017 revision, key findings and advance tables. New York: United Nations, Department of Economic and Social Affairs, Population Division.Google Scholar
- UN Habitat. (2014). The state of African cities, 2014: re-imagining sustainable urban transitions. Nairobi: United Nations Human Settlements Programme.Google Scholar
- United States Environmental Protection Agency. (2002). Federal Water Pollution Act, As Amended Through P.L. 107–303, November 27, 2002.Google Scholar
- Weiss FT, Leuzinger M, Zurbrügg C, et al. (2016). Chemical pollution in low- and middle-income countries. Eawag.Google Scholar
- WHO, A. F. R. O. (2016). Chemicals of public health concern and their management in the African region. Brazzaville: WHO Regional Office for Africa.Google Scholar
- WHO IARC. (1993). IARC monographs on the evaluation of carcinogenic risks to humans. Lyon: International Agency for Research on Cancer.Google Scholar
- WHO IARC. (2006). IARC monographs on the evaluation of carcinogenic risks to humans. Lyon: International Agency for Research on Cancer.Google Scholar
- WHO IARC. (2012). IARC monographs on the evaluation of carcinogenic risks to humans. Lyon: International Agency for Research on Cancer.Google Scholar