Research & reports

Amos Tomiwa Afolabi, Bridget O. Odiyi, Oluwasheun Johannah Ojeniyi · Discover Soil. · Nigeria (Ado-Ekiti)

A study in Ado-Ekiti, Nigeria, investigated heavy metal accumulation in Amaranthus hybridus and Ocimum gratissimum grown on soils from two automobile workshops. A. hybridus accumulated higher metal concentrations than O. gratissimum, with stems showing greater accumulation than leaves. While non-carcinogenic and total cancer risks were within acceptable limits, children showed higher vulnerability, indicating that continuous monitoring and soil remediation are essential for sustainable urban agriculture in these contaminated areas.

Alemseged Gerezgiher Hailu, daniel girmay, samuel ataklti · Discover Food · Sub-Saharan Africa

This scoping review analyzed 155 sources (2009–2024) on urbanization's impact on food security in Sub-Saharan Africa. Findings showed rapid urban expansion converted 30% of peri-urban agricultural land in some regions, increasing dependence on imported staples, and low-income households spend 60–80% of income on food. A policy gap was identified, with only 12% of countries having supportive policies and 19% of cities designating land for farming.

N. I. Odeh, A. T. OGAH, O. C. Odeh · Journal of African Resilience and Advancement Research · Nigeria

This study in Jos Metropolis, Nigeria, examined the urban agriculture (UA) policy framework and household food security using mixed methods, including interviews and a household survey. Findings revealed the absence of a dedicated UA policy, with UA regulated indirectly by general agricultural and land-use policies. Only 20.7% of households were food secure, while 79.3% experienced some level of food insecurity.

Michael J. Ormsby, Luke Woodford, James Joseph Mwesiga, Winnie Ernest, Dativa J. Shilla, Daniel Abel Shilla, Richard S. Quilliam · Environmental Pollution · Africa

This study investigated plastic debris as a reservoir for multidrug-resistant (MDR) enteric bacterial pathogens at two peri-urban agricultural sites in Dar es Salaam, Tanzania. Analysis of 140 environmental samples (soil, water, vegetation, plastic debris) showed higher concentrations of culturable pathogens on plastic debris, with presumptive E. coli loads of ~1 × 10^3 CFU per piece. Plastic debris harbored a greater proportion of MDR strains, including E. coli and K. pneumoniae resistant to critically important antimicrobials, indicating that plastic waste facilitates the survival of MDR pathogens and poses health risks.

Mugabo Kalisa G. · Idosr Journal of Computer and Applied Sciences. · Sub-Saharan Africa

A review article addresses how, in Sub-Saharan Africa (SSA) where malaria transmission is increasing in urban and peri-urban areas due to rapid urbanization and inadequate infrastructure, urban agriculture — a vital livelihood strategy in peri-urban SSA — often intersects with poor water management practices, creating favorable breeding grounds for malaria vectors, particularly Anopheles mosquitoes. It examines the complex relationship between urban agriculture, water management and mosquito breeding in peri-urban areas, including how irrigation systems, water storage and waste management contribute to malaria transmission, and discusses the implications for malaria control. It also reviews emerging technologies such as remote sensing, GIS and mobile health platforms that can enhance mosquito surveillance and community involvement, and calls for a multi-sectoral approach spanning urban planning, vector control and community-based interventions, along with sustainable urban agricultural practices to mitigate malaria risks in SSA.

Adnan Sirage Ali · Discover Public Health · Ethiopia

A comparative cross-sectional study of 315 urban vegetable-farming households along the Akaki Rivers in Ethiopia used structured questionnaires, multivariable logistic regression, multilevel mixed-effects models and bootstrapped mediation analysis. Two-week diarrhea prevalence was 11.4% (36/315) among children and 8.7% among adults; in this cross-sectional design, which cannot establish causality, wastewater irrigation was associated with more than double the odds of diarrhea (AOR=2.10, 95% CI 1.30-3.40), frequent contact with irrigation water with 80% higher odds (AOR=1.80), and regular raw-vegetable consumption with 60% higher odds (AOR=1.60). Handwashing with soap (57% risk reduction), bathing after farm work (41% reduction) and household water treatment (45% reduction, AOR=0.55) were protective, clustering by irrigation site was modest (ICC about 6%), and hygiene practices mediated 28% of the exposure-outcome relationship.

Aminu Zakariyau, Murtala Rabiu · International Journal of Advances in Engineering and Management · Nigeria (Katsina City)

The potential ecotoxicological impacts of municipal solid waste compost (MSWC) on soil, plants, and humans in urban Katsina, Nigeria, were assessed. Analysis of soil mixtures and plant biomass (maize and beans) revealed high phytotoxicity in beans, while maize considered MSWC as phytonutrients. No statistical difference in non-biodegradable substance concentrations in soils and plants was found, and ecological risk index (ERI) indicated low risk; however, Target Hazard Quotients (THQ) suggested a likelihood of non-carcinogenic effects to the ecosystem.

Taffere Addis, Sisay Ketema, Abayneh Melaku · Frontiers in Water · Ethiopia (Addis Ababa)

This study in Addis Ababa, Ethiopia, investigated trace metal levels in sediment, soil, and irrigated vegetables from farms along the Akaki River, evaluating public health risks. Sediment levels of arsenic, chromium, copper, nickel, lead, and zinc exceeded threshold effect levels. Soil levels of arsenic, chromium, copper, manganese, and zinc exceeded typical world soil values, with nickel at one site exceeding EEC limits for agricultural soils. Critically, arsenic, lead, and zinc levels in some vegetable samples were above WHO allowable limits, despite soil levels being acceptable, and cadmium was the most accumulated metal in vegetables.

Tinashe P. Kanosvamhira · Urban Transformations · South Africa (Cape Town)

This qualitative study investigated 13 school-based community gardens in low-income townships on the Cape Flats of Cape Town, South Africa, using semi-structured interviews. It found that while these gardens can enhance food security, nutrition, and community development, most urban community gardens in South Africa face significant challenges related to land tenure rights, often requiring negotiation for school land use. The research highlights both the advantages and the challenges of utilizing school land for community gardens.

Doreen N. Meso, Enos W. Wambu, Gelas Simiyu, Shem M. Mwasi, Thomas Munyao · Discover Environment · Kenya (Kakamega Town)

This study assessed heavy metal pollution in agricultural soils, water, and pumpkin leaves from 21 sites across three zones in peri-urban Kakamega Town, Kenya. It found cadmium pollution in all water samples, and lead and nickel pollution in sections of soil and leafy vegetable samples. Lead pollution was linked to vehicular emissions near the town center, while cadmium enrichment in informal settlements implicated inadequate waste management. Sequential extraction showed 31–35% of soil cadmium was in exchangeable fractions, posing a risk of bioavailability, highlighting persistent heavy metal contamination with implications for public health, environmental sustainability, and agricultural productivity.

Katuka, Stephen Agire, Magaji, Sule, Ismail, Yahaya · Zenodo (CERN European Organization for Nuclear Research) · Nigeria (Abuja)

This study analyzed the impact of rising food prices on the food security of different socio-economic groups in Abuja, Nigeria, using a cross-sectional survey of 400 households. Findings revealed that only 18% of households were food secure, while 56% experienced moderate to severe food insecurity. Food price inflation had a significant negative effect on food security, particularly among low-income households. Rising food prices were shown to increase the likelihood of mild, moderate, and severe food insecurity by 53%, 88%, and 132%, respectively.

Abubakar Mohd Habu, Ali Sanusi Hassan, Adeniyi Olarewaju Adeleye, Michael Edet Nkereuwem, Ijanu Emmanuel Madu, Garba Barde Bate, Olukemi Adeleye, Usman Mohammed Isah · Biological Environment and Pollution · Nigeria

This study assessed heavy-metal accumulation and non-carcinogenic health risks in commonly consumed leafy vegetables -- lettuce, spinach, and cabbage -- cultivated with wastewater in Zawaciki, Kano State, Nigeria. Vegetable and rhizospheric soil samples were analyzed for cadmium, lead, chromium, nickel, zinc, and copper using atomic absorption spectrophotometry, and bioaccumulation factors (BAFs) were calculated as the ratio of metal levels in plant tissue to soil. Metal concentrations varied significantly across the vegetables (p < 0.05), with lead in lettuce leaves exceeding the FAO/WHO permissible limit by more than 120 times; chromium in cabbage reached 32.22 mg/kg, while lettuce showed elevated zinc (19.83 mg/kg) and copper (9.26 mg/kg). Hazard-quotient risk assessments found HQs for chromium and lead both exceeding 1, and the cumulative hazard index exceeded 1 for all vegetables, reaching its highest value of 18.861 in lettuce.

Nolwazi Z. Khumalo, Melusi Sibanda, Lelethu Mdoda · Sustainability · Sub-Saharan Africa

A systematic review and bibliometric analysis examined the implications of climate-smart agriculture (CSA) practices and climate adaptation strategies for food and income security in urban Sub-Saharan Africa. The review found that CSA practices boost urban food production and income, but also recognized critical challenges and trade-offs requiring urban agriculture transformation.

Ivica Petríková, Melvine Anyango Otieno, Gertrude Were, Mahmoud Eltholth, Ana Rodriguez‐Mateos, Seeromanie Harding, Victoria Hall Morán, Odipo Osano, Jennifer Cole · Food Security · Kenya

This study investigated the links between peri-urban households' engagement in agriculture, their dietary behavior, and their children's nutrition outcomes around Eldoret, Kenya. Survey data collected from 518 households indicated that peri-urban households involved in agriculture, particularly crop growing and sales, had more diverse and nutritious diets than non-engaged households. However, a significant improvement in children’s health outcomes in these households was observed only when coupled with improved water, sanitation, and hygiene conditions.

Stefania Lovo, Samantha Rawlings · The World Bank Economic Review · Ghana, Nigeria

This study investigated the impact of e-waste dumping sites on neonatal and infant mortality, focusing on two major dumpsites in Ghana and Nigeria. Using a difference-in-differences approach, outcomes were compared for children born near and far from dumpsites before and after their creation. E-waste sites increased neonatal and and infant mortality for those living closer to the sites, with event studies suggesting effects emerge two to three years after site openings. There is suggestive evidence that contamination of water and of urban farming produce are among the drivers of the observed effects.

Hailekiros Tadesse Tekle, Desta Berhe Sbhatu, Gebreselema Gebreyohannes · H2Open Journal · Ethiopia (Mekelle)

A study in Hadnet district, Mekelle, Ethiopia, assessed heavy metal concentrations in wastewater, spring water, and three leafy vegetables (lettuce, spinach, cauliflower). Wastewater samples from four experimental sites exceeded permissible limits for 4 out of 10 heavy metals (Cd, Cr, Cu, Mn), and spring water from a comparison site also exceeded limits for 4 metals (Al, As, Cd, Cu). Leafy vegetables grown in the least contaminated experimental site showed high concentrations for 6-7 out of 10 heavy metals, with lettuce and spinach having elevated levels of As and Al, respectively. The study concluded that the wastewater used for irrigation is not safe, the farm soils may have accumulated significant heavy metals, and the cultivated vegetables are highly contaminated, necessitating regulation of wastewater use for irrigation.

ke Chinelo Gloria, Eze H.C, Obasi C.J, Euphemia Afoma Ikegwuonu, Okonkwo Ngozi Nonyelum · International Journal of Research Publication and Reviews · Nigeria

To evaluate the water quality of the Obibia River in Amawbia, Anambra State, Nigeria, water samples were collected monthly and assessed for bacteriological and physicochemical parameters. The study identified multiple bacterial isolates, including Escherichia coli, Klebsiella pneumoniae, Salmonella enterica serovar Typhi, and Vibrio cholerae. Notably, E. coli, S. Typhi, and V. cholerae were frequently observed in both rainy and dry seasons. These findings suggest the necessity of adequate treatment before use and periodic evaluation of the water's quality for drinking and urban agricultural purposes.

Arcadius Martinien Agassin Ahogle, Sammy Letema, Gertrud Schaab, Veronica Ngure, Abraham R. Mwesigye, Nicholas Kibet Korir · Frontiers in Soil Science · Kenya (Nairobi)

This study assessed heavy metal and trace element contamination risks in peri-urban farmlands in Nairobi city catchment, Kenya, by analyzing 60 soil samples from ten vegetable farming zones. Results showed elevated concentrations of elements including As, Cd, Mn, Pb, and Zn, with some exceeding permissible agricultural thresholds. As, Cd, Hg, and Pb exhibited high ecological risks, with Cd contributing 46-66% of the overall risk.

Jade Morkel, Noxolo Dumani, Nick Malherbe, Shahnaaz Suffla · Community Development · South Africa

This case study, conducted in a low-income South African community, explored how a community gardener engages with the social solidarity economy (SSE) using thematic analysis of triangulated data from an interview, participant observation, and a participatory film. The study analyzed how the community garden fostered solidarity and established alternative micro-economic practices. It also considered challenges facing community gardens when connecting with the SSE.

Adane Sirage Ali, Sirak Robele Gari, M.L. Goodson, Claire Walsh, Bitew K. Dessie, Argaw Ambelu · PLoS ONE · Ethiopia

This cross-sectional study investigated the prevalence and risk factors of diarrhea among children under five in 402 wastewater irrigation farming households in Addis Ababa, Ethiopia, from November 2021 to February 2022. The overall prevalence of diarrheal cases in children under five was 22.3%. Diarrhea was strongly associated with wastewater-related occupational exposure factors, including body washing with irrigation water, contaminated cloth with irrigation water, use of protective clothing during farm work, use of farm work cloths at home, and bringing unwashed farm tools home.

Clemêncio Nhantumbo, Nídia Cangi Vaz, Mery Rodrigues, Cândido Manuel, Sífia Rapulua, Jéssica Langa, Hélio Nhantumbo, Dominic Joaquim, Michaque Dosse, José João Sumbana, Ricardo Santos, Sílvia Monteiro, Dinis Juízo · Water · Mozambique

A study investigated fecal microbial contamination levels in river water, drainage water, and drinking water in the Infulene River Basin, Mozambique. Samples from the Infulene River and drainage showed 82% positive for Total Coliforms and 61% for Escherichia coli, while drinking water samples were 63% positive for Total Coliforms and 23% for Escherichia coli. The study confirmed a high vulnerability to microbial contamination across all investigated sources due to poor sanitation and a lack of drainage infrastructure.

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.

Njenga John Ng’ang’a, Mukundi John Bosco, Masinde Peter Wasike, Kihurani Agnes Wanjiru · Journal of Agriculture Science and Technology · Kenya (Nairobi)

A study in Nairobi's eastern zone assessed heavy metal occurrence in urban farm inputs and food crops (tomatoes, arrowroots, kales). Cadmium, manganese, lead, and zinc concentrations were analyzed in soil, water, and crop samples. The study found that heavy metal contents, particularly cadmium, manganese, lead, and zinc, were above allowable limits in several crops, and based on FAO/WHO standards, were high for health concern.

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.

Sani Abubakar Mashi, Samuel Yakubu, Sofia Yuniar Sani · Asian Research Journal of Agriculture · Africa

A study in the Kubanni basin of Zaria, Africa, evaluated the quality of wastewater used for irrigating urban agriculture soils. The wastewater contained arsenic, iron, chromium, copper, zinc, manganese, and lead. Although concentrations were generally below Nigeria's permissible limits for irrigation, the study noted the metals' tendency to accumulate in soils, raising concerns about potential heavy metal buildup in irrigated soils and crops.