Research & reports

Mwangi Kamau, Wanjiku Otieno · International Journal of Veterinary Sciences and Animal Husbandry · Kenya

This study characterized the physicochemical quality of untreated wastewater from three small-scale slaughterhouses on the outskirts of Nairobi, Kenya, and measured its effect on soil microbiology at 0, 50, and 200 meters from the discharge point during both wet and dry seasons. Wastewater biochemical oxygen demand (BOD5) ranged from 1,840 to 2,620 mg/L and chemical oxygen demand (COD) from 3,410 to 4,870 mg/L, exceeding Kenyan discharge standards by 6- to 10-fold. Total bacterial counts in soil at the discharge point were 2.7 times higher than at 200 m (p<0.001), and total coliform counts were 4.1 times higher (p<0.001). The Shannon-Wiener diversity index rose significantly with distance from the discharge point (1.42±0.14 at 0 m vs. 2.34±0.18 at 200 m; p<0.001), indicating that wastewater irrigation selects for a less diverse, coliform-dominated soil microbial community. Seasonal variation was significant for BOD5 and coliform loading but not for the diversity index.

Gizaw Ebissa, Aramde Fetene, Hayal Desta · City and Environment Interactions · Ethiopia

Treated wastewater from the plant serving Bole Lemi Industrial Park (BLIP) in Addis Ababa, Ethiopia was sampled at the treatment plant's influent and effluent and analyzed using a treated wastewater quality index (TWWQI) to assess suitability for urban irrigation agriculture. The aggregate TWWQI classified the water as 'very poor' for urban irrigation agriculture, with heavy metals contributing 85% of that grade, nutrient load 4%, salinity 8%, and miscellaneous contaminants 4%. Discrete indices varied: heavy metals scored 'very polluted', nutrients 'excellent', salinity 'poor', and miscellaneous contaminants 'good'. Contaminant removal efficiency ranged from 30% to 100% (58% in aggregate), and some contaminants showed higher concentrations in the effluent than the influent, indicating the treatment plant failed to remove them. Cr3+, Cl− and TDS contributed most to the poor rating, and the plant was found to need upgrading to increase removal efficiency.

Yosef Abebe, Mulugeta Gashaw, Asenake Kefale, Tim Brewer · Water Reuse · Ethiopia

A study on wastewater governance in the upstream catchment of the Awash Basin, Ethiopia, found that untreated wastewater discharged from industries is polluting rivers and the surrounding environment. Regulatory bodies have done little to enforce rules and directives for wastewater regulation, and due to poor implementation of laws, urban agriculture is expanding without concern for its negative health and socioeconomic impacts.

Ambroise Dalecky, Madougou Garba, Abdoulaziz Ibrahim Danzabarma, Jonas Etougbétché, Sylvestre Badou, Henri‐Joël Dossou, Ibrahima Sow, Cheikh Tidiane Niang, Ousmane Diene, Idrissa Diallo, Mohamed Seyidna Ali Saghiri, Mohamed El Hady Sidatt, Frank van Steenbergen, Amadou Bocar Bal, Luwieke Bosma, Gualbert Houémènou, Solimane Ag Atteynine, Karmadine Hima, Gauthier Dobigny, Yonas Meheretu · Environnement Risques Santé · Sub-Saharan Africa

The abstract text provided consists only of acknowledgments—thanking Valérie Golaz (INED-LPED), Marc Egrot (IRD-LPED), and the organizers of the international conference "Implementation of public policies and pesticides in the Souths" (PoPPesCI project, on public policies and pesticides in urban agriculture), held in October 2021 in Bouaké, Côte d'Ivoire, for prompting the article's writing. It contains no actual findings or content about rodent proliferation or synthetic chemical rodenticides despite what the title suggests.

I. K. Adewumi, Adebanji Samuel Ogbiye, E. O. Longe, David O. Omole · Covenant University Repository (Covenant University) · Nigeria (Ota)

This study assessed the impact of industrial wastewaters discharged into River Atuwara in Ota, Nigeria, on water quality using standard physical and chemical analyses and QUAL2K software. The majority of water quality parameters exceeded maximum permissible concentrations, with BOD at ≥ 31 mg/L, COD at ≥ 181 mg/L, and alkalinity at ≥ 138.4 mg/L. High concentrations of heavy metals, including Cadmium, Pb, Zn, Fe, and Mn, were detected, indicating an environmental hazard for riparian users.

Mark Matsa, Thomas Marambanyika · Journal of Environmental Extension · Africa

A study assessing concentration levels of lead (Pb), cadmium (Cd) and sulphides (SO2) within and around Gweru's sole official waste dumpsite in Zimbabwe. Harsh economic conditions in the city have driven further expansion of urban agriculture on open spaces, with residents growing staple food crops such as maize and sweet potatoes for subsistence on numerous plots surrounding the dumpsite; the study states that ingesting crops grown near the dumpsite is likely to put residents' lives at risk. Soil sampling points along transects on and around the dumpsite were randomly selected using ArcView GIS, with sulphide concentrations measured by Leco machine and lead and cadmium by atomic absorption spectrometer. Independent t-test results showed the concentration levels of the three pollutants were significantly elevated from one sampling point to the next, within and around the dumpsite.

Adedeji Adedeji, H Oludare, Ademiluyi · Journal of Geography and Regional Planning · Nigeria

This discussion of urban agriculture and urban land use planning in metropolitan Lagos, Nigeria, frames urban agriculture as a crisis response and survival strategy for the urban poor that contributes to food security, while stating that urban agriculture production systems can pose risks to public health and the environment through inappropriate or excessive use of agricultural inputs — including pesticides, nitrogen, and raw organic matter containing heavy metal residues. It recommends that urban land use planners promote multifunctional land use and greater community participation in managing urban open spaces.

Erastus K. Kang’ethe, Delia Grace, Thomas F. Randolph · East African Medical Journal · East Africa

This study synthesizes current knowledge on urban agriculture (UA) in East Africa, focusing on its human health impact. It identifies UA as an important source of food security, but notes that many zoonotic and food-borne diseases are associated with it, with a lack of evidence on human health impact and management. Major constraints include illegality and limited access to inputs and markets, indicating a need for more research to understand both positive and negative health impacts.

Pay Drechsel, Olufunke Cofie, R. van Veenhuizen, Theophilus O. Larbi · Irrigation and Drainage · West Africa

Informal irrigation in urban and peri-urban agriculture (UPA) in West Africa offers benefits but is often hindered by water pollution, threatening public health. A multi-stakeholder process implemented since 2005 in six West African cities, including Accra, Ghana, aimed to integrate UPA into sustainable urban development. However, an internal lesson learned was that local partners may not prioritize every project, and capacity-building efforts might not provide expected incentives for commitment.

Halidou Koanda · Infoscience (Ecole Polytechnique Fédérale de Lausanne) · Sub-Saharan Africa

In Sub-Saharan Africa, faecal sludge management practices are often financially unviable due to widespread lack of municipal involvement, paucity of legal provisions, and absence of stakeholder coordination. This leads to indiscriminate dumping of faecal sludge in urban areas or its untreated use in urban agriculture. These practices pose permanent and serious health risks and contaminate scarce ground and surface water. This research aims to develop an innovative strategic planning approach for sustainable urban faecal sludge management to minimize public health and environmental risks.

Tony Binns, Roy Maconachie, Adamu Idris Tanko · Land Degradation and Development · Nigeria (Kano)

This paper examines health and environmental concerns associated with urban and peri-urban agriculture (UPA) in Kano, Nigeria. Empirical evidence indicates that industrial and domestic toxins are reaching dangerously high levels, leading to significant pollution of soils and water channels. This raises serious questions about the sustainability of UPA and the long-term health implications of toxin exposure.