Research & reports

Ndiaye Awa, Diallo Ibrahima, Dieng Amadou, Ba Ibrahima, Sembene Mbacke · African Journal of Environmental Science and Technology · Senegal

This study in Dakar, Senegal, assessed Salmonella contamination in irrigation water and lettuce across three urban agricultural sites. Sites using wastewater (Pikine and Patte d’Oie) showed high Salmonella prevalence in water (70-90%) and vegetables (20-80%), while a tap water site (Lendeng) had no contamination. Market-sourced lettuce also tested positive (28.57%), indicating public health risks from untreated wastewater use.

Réné Kasende Disashi, Belloty Mundadi Ngeteke, Dorcas Sola Tabitha, Prescilia Mabubu Pembe, Fanny BAKOMBA KIKOBO, Denise OKITO WIKANU, Esther MPIANA MUKANIA, Sarah Kinsona Bombili, Esther Kimpala Karuna, Clément Munganga Kilingwa, Rosie Mubindukila Nzamba · European Scientific Journal ESJ · Congo (Kinshasa)

A study conducted from June 10 to July 20, 2025, in peri-urban market gardens of Kimwenza and Ndjili Cecomaf in Kinshasa, Democratic Republic of Congo, surveyed 68 market gardeners on the use of prohibited and unauthorized pesticides. The findings revealed an alarming reliance on informal supply channels, with six out of 27 identified pesticides being formally prohibited. Despite 94.3% of gardeners acknowledging risks, only 9.6% used full protective equipment, and 32.7% took no precautions.

Bahi Aristide Armand, Ohou-Yao Marie Jeanne, Kouamé Leonard Kouadio, Sahiri Grâces Kérène, Akpètou Lazare, Akessé Djamatché Paul, Koné Oumar, Dongui Bini Kouamé · International Journal of Environment and Climate Change · Côte d’Ivoire (Daloa)

This study characterized the physicochemical quality of surface waters at 30 sampling points in lettuce and rice cultivation areas in Daloa, Côte d’Ivoire, from January 2024 to January 2025. Physicochemical analyses revealed spatial variability in water quality parameters, with marked fluctuations influenced by agricultural activities. The findings indicate that surface waters are exposed to contamination from farming practices, domestic activities, and rapid urbanization.

Nelson Joseph Msacky, Amelia Alfred, Oscar Punguti, Edson Protas, Iddi Mapande, Novatus, Shukrani Phillip, January G Msemakweli · Open MIND · Global

This systematic review aims to synthesize current scientific evidence on the effectiveness of fruit-waste-derived biochar in immobilizing potentially toxic elements (PTEs) in contaminated agricultural soils. It will evaluate how fruit-waste biochar reduces metal bioavailability, plant uptake, and associated human health risks from vegetable consumption. The review also seeks to identify which fruit wastes are used as biochar feedstocks and which biochar properties and production conditions influence immobilization performance, noting that existing research is fragmented.

Hajra Kanwal, Qudrat Ullah, Waqas Haider, Mujahid Farid, Zaki Ul Zaman Asam, Muhammad Zubair, Abdulrahman Alasmari, Sarah Owdah Alomrani, Muhammad Munir, Shafaqat Ali · Open MIND · Global

This study investigated the interactive effects of contaminated wastewater with cadmium, mercury, lead, and polyethylene microplastics from exfoliating personal care products on chili plants (Capsicum annuum). Plant growth parameters were reduced by 71–82% at high wastewater and microplastic levels, accompanied by significant losses in photosynthetic pigments and soluble proteins. Oxidative stress markers increased by 124–230%, and heavy metal uptake was significantly increased, facilitated by microplastics.

hawamkwela@yahoo.com MKWELA · Social Sciences & Humanities Open · Tanzania (Dar es Salaam)

This systematic review analyzed 42 studies from 1990 to 2024, examining urban agriculture practices, scale, socio-economic contributions, health and environmental impacts, and governance constraints in Dar es Salaam, Tanzania. Urban agriculture involves 36,000–60,000 households cultivating 1,800–6,000 hectares annually, supplying 90% of city vegetables, providing 20–70% of household income, and employing over 100,000 people. However, 85–95% of farmers lack secure land tenure, 78% of vegetable samples exceed WHO E. coli limits, and 90% of produce is sold informally with high post-harvest losses of 20–40%.

Jenkins E. M., Heafner H., Montgomery J., Soumano V., Paltseva A. A. · iScience · 米国・シカゴ

Portable X-ray fluorescence measurement of seven trace elements in 233 topsoil samples from five Chicago parks. Lead, arsenic, copper, zinc and chromium exceeded Illinois background levels in 89–100% of samples; arsenic exceeded EPA screening levels in 94% of samples and lead in 7%. Contamination was higher at parks farther from the city centre — Douglass and Humboldt parks, in predominantly minority, lower-income neighbourhoods — than at Cottontail, Grant and Webster. Principal-component analysis identified an anthropogenic signature (PC1, 51.7%) driven by Pb, Zn, Cu and As and a geogenic signature (PC2, 17.0%) associated with Mn and Ni. Areas of Douglass and Humboldt parks were classified as not safe for gardening in native soil; Webster as safe with minor restrictions. The authors conclude that park-soil contamination follows socioeconomic gradients, reflecting environmental injustice and a need for targeted remediation.

Malsha Samarasiri, Wei Ning Chen · Sustainable Microbiology · Global

This review discusses advances in urban mushroom farming, its integration with computer-based technologies, safety considerations, and the potential of mushrooms and mycelium-based foods as future foods. Key safety considerations for urban mushroom farming systems include biological hazards, mycotoxins, heavy metal accumulation, and potential allergenicity. Macrofungal mycelium-based foods may be regarded as novel foods and require evaluation under novel food safety regulations.

Djim-adjim Tabo, Fissou Henry YANDAI, BONGO NARE Ngandolo, GRANIER Sophie, ABAKAR Brahim, MILLEMANN Yves · European Journal of Nutrition & Food Safety · Chad

A study in N'Djamena, Chad, isolated Salmonella and Escherichia coli from wastewater discharged into the Chari River and from market garden crops irrigated with it. E. coli was found in 29.66% of wastewater samples and Salmonella sp. in 19.49%, with raw vegetables showing very high contamination. Wastewater results exceeded WHO standards, indicating that re-use of this wastewater for market gardening is not recommended due to significant contamination risks.

Gabson Baguma, Gadson Bamanya, Allan Gonzaga, Hannington Twinomuhwezi, Barnabas Mubangizi, Eric Niringiyimana · Pollutants · Uganda

This review synthesized literature on the occurrence of cadmium, chromium, nickel, lead, and arsenic in foods consumed in Uganda. Contamination was concentrated in mining-influenced agricultural areas, wastewater-irrigated farms, municipal dumpsites, industrial corridors, and urban food markets, with vegetables, cereals, livestock products, fish, and street-vended foods exhibiting the greatest contamination burdens. Lead and cadmium most frequently exceeded WHO/FAO, Codex Alimentarius, and Ugandan food safety limits, and children consistently showed higher dietary exposure than adults.

Jennifer Newell, Rory Doherty, Gary Lyons, Siobhan F. Cox · Environmental Geochemistry and Health · Global

A controlled experiment investigated the effects of 5%w/w digestate biochar on lead (Pb) ingestion risks in urban vegetable agrisystems with varying soil Pb concentrations, high pH, and organic matter. Biochar significantly reduced soil-derived Pb ingestion risks in some systems but had no effect on vegetable-derived Pb ingestion risks for any agrisystem. Overall, biochar showed limited and variable effects on reducing Pb ingestion risks, suggesting its remediation potential is context-dependent and may offer limited protection in soils with elevated pH and organic matter.

Eric Vukicevich · Urban Ecosystems · Global

This paper describes a class-based soil testing project where undergraduate students partner with local community gardeners to investigate urban soil health. The project involves students examining soil properties such as pH, organic matter, nutrients, and toxic elements, and ensuring crop safety. Students develop project plans, interpret data, and make recommendations for soil management.

Kamil Pająk, Alicja Trawińska, Marcin Łapicz, Andrzej R. Reindl · Toxics · Global

This study quantified emissions and toxicological consequences of a large-scale tire fire in an urban ecosystem by analyzing soil samples from the fireground and surrounding urban allotment gardens for zinc and 16 polycyclic aromatic hydrocarbons (PAHs). Soil at the fire site showed severe contamination with PAHs (Σ PAHs: 148.9 mg/kg), and the cumulative Incremental Lifetime Cancer Risk (ILCR) for children reached 9.7 × 10−4, exceeding the regulatory benchmark. Elevated risk levels persisted at distal residential sites, indicating long-term environmental contamination and persistent terrestrial health hazards.

Karina Corada, Caroline Nash, Prashant Kumar, Stuart Connop, Laura Wendling · Nature-Based Solutions · Global

A synthesis paper on the largely unexplored role of domestic gardens in influencing local air quality. While gardens are widely recognized for cultural and health benefits, particularly mental well-being and everyday contact with nature, the paper states few studies have examined air quality dynamics within residential garden settings. It notes that general urban green infrastructure research suggests vegetation structure, plant traits, and spatial configuration shape pollutant capture, but these findings have not been tested in domestic gardens, where microclimates and spatial constraints differ markedly. Evidence from food-growing gardens and allotments further suggests edible crops cultivated near roads may accumulate airborne pollutants, particularly metals, underscoring the need for research on exposure pathways and allotment locations. The paper identifies a significant gap in current green infrastructure and air-pollution research: the lack of empirical evidence on how domestic gardens function as socio-ecological systems with implications for air-quality regulation.

Nwanaforo E., Obasi C. N., Akande I. O., Nduka J. K., Offor C. C., Abdulai P. M., Udom G. J., Orisakwe O. E. · Biological Trace Element Research · ナイジェリア（オウェリ・アバ・ポートハーコート）

A study of lead, cadmium and copper in urban agricultural systems in three industrial-area Nigerian cities (Owerri, Aba and Port Harcourt), assessing spatial distribution, bioaccumulation and health risks using both deterministic and stochastic (Monte Carlo) approaches. Atomic absorption spectrophotometry found soil concentrations following Pb > Cu > Cd in Owerri and Port Harcourt but Pb > Cd > Cu in Aba, while fish and vegetables followed Pb > Cd > Cu at all three sites. The deterministic assessment found cadmium's incremental lifetime cancer risk exceeded the US EPA acceptable threshold of 1×10⁻⁶ at every site for every sample examined, identifying cadmium as the metal of greatest concern.

Hoque MN, Rana ML, Gilman MAA, Pramanik PK, Islam MS, Punom SA, Rahman R, Hassan J, Rahman MS, Ramasamy S, Schreinemachers P, Oliva R, Rahman MT · Environmental Monitoring and Assessment · バングラデシュ・ダッカ／ガジプール

A shotgun metagenomic study motivated by how little is known about the microbial communities and antimicrobial resistance (AMR) profiles of rooftop and surface garden soils in Bangladesh, and their potential role as reservoirs and disseminators of AMR, despite the growing expansion of urban agriculture. Twenty-seven soil samples were sequenced — 7 from Dhaka rooftop gardens, 6 from Dhaka surface gardens, 8 from Gazipur rooftop gardens and 6 from Gazipur surface gardens. The work identified 88 antibiotic resistance genes (ARGs), of which 19 (21.6%) were shared across all sites, and found significant differences in resistome composition by garden type (p = 0.04). Rooftop soils harboured more ARGs (Dhaka 50, Gazipur 48) than surface soils (Dhaka 40, Gazipur 41) and were dominated by glycopeptide resistance genes, collectively 62.43-74.07% of ARGs; rooftop soils were also enriched in efflux pumps (adeF, 45.21% of rooftop ARGs) and the ribosomal-protection oxazolidinone resistance gene O23S (62.13% in Gazipur rooftops). Surface soils instead featured more genes mediating antibiotic inactivation, such as CATA (11.64% in Dhaka surface gardens) and fosBx1 (5.94% of surface ARGs).

Oyewole Michelle T., Pellow David N., Cassels Susie · Environmental Justice · 米国

A study measuring soil lead by X-ray fluorescence at 31 Brooklyn public schools with active garden programmes, sampling both garden beds and adjacent school grounds. Proximity to 306 known environmental hazard sites was mapped geostatistically and combined with demographic data and soil-management surveys. Of the samples, 42% exceeded the US EPA's minimum screening level for child-accessible soils near known lead sources (100 ppm); garden soils showed lower average lead concentrations than adjacent school-ground soils. The authors argue that soil lead in schools, and the disparities in it, have received far less attention than lead in paint and water.

Olabode K., Lewińska K., Komorowicz I. · Environmental Geochemistry and Health · ポーランド南部・ズウォティストク（旧鉱山地域）

Quantifies total arsenic, gastric-phase in vitro bioaccessible arsenic (IVBA) and direct-soil-exposure risks for children and adults in mining-affected allotment gardens in Złoty Stok, southern Poland, applying deterministic calculations and Monte Carlo simulation to incidental soil ingestion, dermal contact and inhalation of resuspended particles. Total As ranged 433–1148 mg/kg and IVBA 4.5–23.5%. Under the total-As multi-pathway scenario median hazard indices were 5.50 for children and 0.62 for adults (P05/P95: 2.26/15.18 and 0.29/1.89). Median total cancer risk was 1.78×10⁻⁴ for children and 1.06×10⁻⁴ for adults, with 80.0% of simulated child profiles and 54.0% of adult profiles at or above 10⁻⁴. Ingestion and dermal contact accounted for nearly all modeled risk while inhalation was negligible; applying IVBA to the ingestion pathway alone cut the median ingestion-related hazard quotient and cancer risk by 89.3%. Total soil As and soil ingestion rate were the principal positive risk drivers, body weight inversely associated.

Pritom Kumar Pramanik, M. Nazmul Hoque, Md. Liton Rana, Md. Saiful Islam, Md. Ashek Ullah, Fahim Haque Neloy, Srinivasan Ramasamy, Pepijn Schreinemachers, Ricardo Oliva, Md. Tanvir Rahman · PLOS ONE · Bangladesh (Dhaka)

Researchers sampled 145 items — 88 raw vegetables, 27 water and 30 soil samples — from rooftop and surface gardens in urban Dhaka North and Dhaka South City Corporations and peri-urban Gazipur City Corporation, Bangladesh, testing for Escherichia coli by culture, biochemical tests and malB-gene PCR. Overall prevalence was 58.62% (95% CI 50.48–66.31): 80.0% in Dhaka South, 44.70% in Dhaka North and 76.7% in Gazipur. In Dhaka, surface gardens were more contaminated (70.83%) than rooftop gardens (46.57%), while in Gazipur rooftop gardens were worse (93.33% vs 60.0%). Of 54 randomly selected isolates, 100% were resistant to ampicillin, with resistance to ciprofloxacin (25.92%), tetracycline (14.81%) and imipenem (9.25%); 14.81% were multidrug resistant and 81.48% carried blaTEM. Home-grown urban vegetables are not automatically hygienically safe.

Paula Marques Crelier, Manoel Jerônimo Moreira Cruz, Danusia Ferreira Lima · Seven Editora eBooks · Global

A controlled laboratory experiment cultivated BRS Leila lettuce (L. sativa) in samples contaminated with lithium carbonate (Li₂CO₃) at concentrations of 150 and 200 mol/L. The study found that lithium correlates with other alkaline and alkaline earth elements in the leaves and roots of the lettuce. This indicates a contamination pathway where lithium is absorbed by the plant.

Godswill Ntsomboh Ntsefong · IntechOpen eBooks · Global

This chapter examines the global growth and implications of urban agriculture. While urban agriculture enhances food security, it also introduces food safety risks from contaminated soils and infrastructure gaps. Challenges related to heavy metals, waste, and inadequate land planning are evaluated, and barriers such as land access and limited training for producers persist.

Christian Valderrama, Hernan Zarate · Ambiente & sociedade · Colombia (Neiva)

This research characterized the presence and spatial distribution of lead (Pb) concentrations in Mangifera indica and Syzygium malaccense fruit trees on public roads in Neiva, Colombia. Using a census, fruit sampling, and spatial interpolation methods, lead levels were detected in all samples. Five samples exceeded the permissible limit of 0.1 mg/kg, with higher concentrations observed in industrial areas.

Ebenezer Boahen · Discover Agriculture · Ghana

This study assessed the awareness and practices of 50 purposively selected vegetable farmers along the Accra-Tema Motorway, Ghana, regarding heavy metal contamination from vehicular emissions and its potential health implications. Data were collected through structured questionnaires and one-on-one interviews. Results showed that 96% of the farmers were unaware of heavy metal contamination, though 80% expressed a willingness to discontinue farming near the motorway if they were informed of the risks. Farmers face challenges such as limited access to clean irrigation water and dependence on informal agricultural knowledge. The study highlights the urgent need for targeted educational interventions to raise awareness about the risks of heavy metal exposure and to encourage safer farming practices.

YAO, Kouadio Assemien François, OUEDRAOGO, Moussa, BROU, Konan Richmond, COULIBALY, Léréyaha, OUATTARA, Ismaïla, N'CHO, Odon Clément, YAO, Koffi Blaise · Zenodo (CERN European Organization for Nuclear Research) · Côte d'Ivoire

Nine groundwater samples were collected in March 2025 from urban farming areas of the Man municipality, western Côte d’Ivoire, to assess their physicochemical and metallic quality. Analysis revealed high concentrations of major ions and nitrites (up to 101.7 mg/L) in the groundwater, exceeding WHO standards. Extreme pollution by cadmium, iron, and zinc was confirmed, with an overall contamination degree of 793.6. These groundwaters are unsuitable for human consumption and require regular monitoring and sustainable water resource management.

K M Tanjida Islam, Md Shahin Mahmud · Pharmacon Jurnal Farmasi Indonesia · Bangladesh

This study characterized multidrug-resistant (MDR) Shigella flexneri strains from contaminated raw vegetables in Bangladesh, retrieved from the NCBI genome database. Whole-genome sequences of four S. flexneri strains from tomatoes and green chilies in Gazipur and Dhaka were analyzed. The analysis identified 4273 core genes and 44 antibiotic resistance genes, with five essential hub genes (tolC, acrA, emrK, emrB, evgS) identified as high-priority therapeutic targets for compromising MDR mechanisms in food-borne S. flexneri.