Research & reports

Nontokozo Pertunia Mkhonza, Sandisiwe Zondo, Samukelisiwe Vilakazi · Environmental Monitoring and Assessment · Africa

A systematic review synthesising 38 peer-reviewed studies (2010–2024) on heavy metals in African urban soils. Weighted mean concentrations of lead, cadmium and chromium exceeded FAO permissible limits in many countries, and industrial activity plus traffic emissions accounted for over half of the identified contamination sources. The review also documents strong geographic bias — Nigeria and Ghana are well studied while Egypt and Ethiopia are barely covered — and a shortage of measurements of bioavailable metal fractions, so the actual dietary risk from crops grown in these cities cannot be determined from this evidence base.

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.

Meron Worku, Michelle Holdsworth, Marie T. Ruel, Ana Irache, Kaleab Baye, M Catherine Spires, Nicolas Bricas, Rebecca Pradeilles · Maternal and Child Nutrition · Africa

A Photovoice study in Addis Ababa, Ethiopia, had women of reproductive age photograph challenges to healthy diets for themselves and their children under five, then discussed the images in five focus groups (n=31 women) split by lower and higher socioeconomic status, analyzed with hybrid deductive-inductive thematic coding. Financial and physical barriers to accessing healthy food, time constraints and perceived poor food safety were major shared contributors to poor diets; lower-SES women also cited limited nutrition knowledge, inadequate family support and poor home food environments, while higher-SES women cited unhealthy food preferences combined with easy access to and aggressive promotion of unhealthy foods. Proposed solutions included government-level measures (job creation, nutrition education, affordable healthy food, household infrastructure investment, expanded childcare, restrictions on unhealthy-food promotion) and societal-level measures (gender equality, community-based loan schemes, and support for urban agriculture).

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.

Lloyd Chigusiwa, Asankha Pallegedara, Terrence Kairiza · Australian Journal of Agricultural and Resource Economics · Sub-Saharan Africa

Using four pooled annual cross-sectional surveys of Zimbabwean urban households from 2019 to 2023, this analysis applied an endogenous switching model with count outcome (ESMC), with propensity score matching as a secondary robustness check, to estimate the effect of urban agriculture on household dietary diversity. Large households, and those headed by women, older heads, or married couples living together, were more likely to practice urban agriculture; practicing urban agriculture increased the likelihood of greater dietary diversity, but this effect held only for the sub-population of households that did not receive support from rural relatives.

Macharia M.W., Caproni L., Solemanegy M., Takele R., Chiulele R.M., Munisse P., Amane M., Pè M.E., Buizza R., Dell'Acqua M. · Communications Biology 8:834 · Africa

Genotypes 389 cowpea accessions (mostly landraces) from Southern Africa and identifies 36 genomic loci linked to local climate adaptation, highlighting the breeding value of farmer-conserved resources.

Mike Murphy, Githenya Wachira, Cecilia Onyango, Vivian Hoffmann · Environmental Science and Pollution Research International · Kenya (Nairobi)

A study that randomly sampled leafy greens from farms across Nairobi, Kenya, and measured lead, cadmium and mercury. Mean concentrations were 0.68 ppm lead, 0.09 ppm cadmium and 0.11 ppm mercury; plots closer to roads had higher lead and plots near industrial sites had higher mercury. Leafy greens alone pushed 71% of adults and 69% of children above safe lead exposure limits, and 52% of adults above the mercury limit. Comparison greens sourced from outside Nairobi were similarly contaminated, so the authors do not treat contamination as unique to urban farming and instead call for systematic food surveillance in low- and middle-income countries.

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.

Mumuni Adejumo · Journal of Health and Environmental Research · Nigeria (Ibadan)

This cross-sectional study surveyed 312 residents in Ibadan North Local Government Area, Nigeria, to document their knowledge and perception of using greywater for backyard cultivation of native herbs. The findings revealed that 70.7% of participants had poor knowledge about greywater and its use for cultivating local herbs, and 61% held a negative perception. Only 8% of participants reported having used greywater in their residence, with 70.8% of public servants specifically showing negative perceptions.

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.

Tinashe P. Kanosvamhira · Journal of Agriculture Food Systems and Community Development · South Africa (Cape Town)

This study investigated the motivations for urban gardening among low-income residents in Cape Town's Cape Flats, South Africa, using survey data from 97 participants and interviews across 34 community gardens. While 29 out of 34 gardens prioritized income generation, a tension was found between institutional economic objectives and individual gardeners' motivations. Although 76.3% cited economic reasons, all respondents also valued social, health, and environmental benefits, perceiving gardening as a means to enhance well-being and promote sustainable practices despite structural barriers.

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.

Ebimorboere endoni, Ibrahim Umar, Patrick Chukwuemeke Uwajeh, Timothy Onosahwo Iyendo, olawepo ibidolapo · Nile Journal of Engineering and Applied Science · Nigeria

This research investigates the role of community recreational gardens in fostering social cohesion among residents in urban housing estates in FCT Abuja, Nigeria, using a mixed-methods approach including surveys, interviews, and observational studies. Key findings indicate that community recreational gardens serve as inclusive environments, promoting cross-generational interactions, cultural exchange, and the formation of social networks in housing estates.

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.

Teófilo Etelvino do Amaral, Carlitos Luí­s Sitoie · LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) · Mozambique (Maxixe)

A school garden project was implemented at Escola Secundaria 29 de Setembro da Maxixe in Mozambique, integrating it into the geography curriculum. Research found that geography teachers only taught theoretical content, lacked practical understanding of the geographical relationship with local agricultural production, and did not value food from home gardens. Students and their parents also had no knowledge of vegetable gardens and preferred processed foods, which exacerbated hunger when they lacked money. The school garden was suggested as a means to produce healthy food and generate family income.

Abraham Woru Borku, Abera Uncha Utallo, Thomas Toma Tora · Discover Food · Ethiopia

A mixed-methods study in selected towns in Southern Ethiopia surveyed 310 households to identify determinants of urban household vulnerability to food insecurity. The results indicated that 41.3% of households were highly vulnerable, 48.3% moderately vulnerable, and 10.6% not vulnerable. Significant determinants included household ownership of houses, health status, urban agriculture, socio-cultural practices, asset ownership, age, and average monthly income.

Akuto Akpedze Konou, Kossiwa Zinsou-Klassou, Victoria M. Mwakalinga, Jean-Claude Baraka Munyaka, Armel Firmin Kemajou Mbianda, Jérôme Chenal · Sustainability · Africa

This perceptual study surveyed 733 urban farmers in Dar es Salaam and Greater Lomé to explore the psychosocial effects of urban agriculture on their well-being. Using the Mental Health Continuum–Short Form and bespoke questionnaires, the research found significant variations in urban agriculture-related happiness across city zones, with peripheral farmers reporting greater satisfaction than urban counterparts. Female farmers also reported higher levels of happiness.

Michael Rudolph, Evans Muchesa · Suid-Afrikaanse tydskrif vir landbouvoorligting/South African journal of agricultural extension · South Africa (Johannesburg)

This article explores the potential of agroecology to address health disparities in urban communities in South Africa, where approximately 34% of Johannesburg households face food insecurity. A transdisciplinary literature review, using secondary data from the University of Johannesburg and Siyakhana Growth and Development, posits that an agroecological approach can effectively address food and nutrition insecurity. The study emphasizes the importance of localized food production, personalized training, and a supportive policy framework for urban farming and agroecology.