Research & reports

Michelle L. Kaiser, Michele L. Williams, Nicholas T. Basta, Michelle D. Hand, Sarah Huber · Journal of Food Protection · 米国・オハイオ

Focus groups (n=67) in four low-income Ohio neighbourhoods plus soil tests at six sites. Residents wanted gardens for fresh produce but worried about soil. Lead, zinc, cadmium and copper were present (paint likely main source); arsenic/chromium and PAHs were low. Further management to cut Pb/Cd bioavailability is needed before food crops; longer-established gardens showed lower contaminant signals. Critical evidence that vacant-lot gardening requires soil risk assessment.

Daniel Andrés Vega Castro, Ángela Patricia Salamanca Rivera · Luna Azul · Colombia (Bogotá)

A study measured lead content in common chard (Beta vulgaris L., acelga) grown in an urban garden within 500 meters of two major roads in Bogotá, Colombia (at coordinates 4°42'39.6"N, 74°5'46.6"W). Before planting, lead content in the cultivated soil and irrigation water was analyzed as a preliminary diagnosis of possible contamination sources. Cultivation was done by hand, with no fertilizer or pest-control products applied to avoid bias. At harvest, 10% of the total planted population was randomly sampled and analyzed by atomic absorption spectrophotometry following AOAC official method 968.08, yielding 0 ppm lead. Based on this result, the authors conclude that urban agricultural production can be an option that supports food security, not only through macro- and micronutrient intake but also through food quality and safety, since no lead was detected in the plant tissue.

Nimoh Fred, Ohene-Yankyera Kwasi, Poku Kofi, Konradsen Flemming, Claude-François Robert · Journal of Development and Agricultural Economics · Ghana

A study in Ghana's Shai-Osudoku district investigated farmers' attitudes toward excreta reuse for peri-urban agriculture, surveying 400 randomly selected respondents. A majority of respondents disagreed that excreta are waste and were willing to use them as fertilizer. However, a majority also agreed that excreta can pose health risks, and perceptions on reuse differed among households.

Aminata Koné, Kouamé M. Adou · Zenodo (CERN European Organization for Nuclear Research) · Congo (Kinshasa)

This article details a methodology developed in 2014 to assess the association between heavy metal contamination in market-sold vegetables and consumer biomarker exposure in Kinshasa, Congo. The cross-sectional design includes stratified random sampling of vendors, laboratory analysis of leafy vegetables for lead, cadmium, and mercury, recruitment of regular consumers for interviews and blood/urine sample collection, and statistical analysis using multiple regression. The described protocol was successfully piloted, demonstrating feasibility with a high participant recruitment rate.

Muhammad Zaman, Faqir Muhammad Anjum, Ali Asghar, Muhammad Sajid · · Pakistan

This study estimated organophosphate pesticide exposure from okra and brinjal consumption in urban populations of Punjab, Pakistan. 90 samples each of okra and brinjal were collected from peri-urban areas of Faisalabad, Multan, and Gujranwala and analyzed for chlorpyrifos, profenophos, and triazophos residues. Findings showed that 85 (47.22%) of the 180 samples were contaminated, and 15 (8.33%) samples had residue values higher than Maximum Residue Limits (MRLs).

Pay Drechsel, Andrew Adam‐Bradford, Liqa Raschid-Sally, Drechsel, Pay, Adam-Bradford, A., Raschid-Sally, Liqa · AgEcon Search (University of Minnesota, USA) · Ghana

This chapter introduces urbanization in West Africa, particularly Ghana, the general role of urban agriculture, and the common use of polluted irrigation water. It focuses on irrigated smallholder vegetable production, reflecting on the key challenges, dynamics, and resilience of this farming system.

Gideon Aghaindum Ajeagah, Yaka Diane Armelle Moussima · Journal of Ecology and the Natural Environment · Cameroon

A study in an urban stream in Yaoundé, Cameroon, characterized Balantidium coli cysts and evaluated environmental factors influencing their dispersal. Round (825 ± 610 cysts/L) and oval (246 ± 300 cysts/L) cysts were found. High abundances of cysts were observed in stations along a piggery effluent near a major market, with higher densities recorded during the short rainy season. The lowest cyst densities were found upstream and downstream.

Abdirahman Osman Warsame, Fadumo Abdi Mohamud, Ahmed Hassan Ali · Zenodo (CERN European Organization for Nuclear Research) · Democratic Republic of the Congo (Kinshasa)

This scoping review synthesized evidence on the association between heavy metal contamination in vegetables sold in Kinshasa's urban markets, Democratic Republic of the Congo, and human biomarkers of consumer exposure. Available evidence consistently showed that vegetables, particularly leafy greens, from Kinshasa markets contained elevated levels of lead and cadmium, often exceeding international safety limits. However, studies directly linking vegetable contamination with human biomarkers are notably scarce, suggesting a potential exposure pathway but not establishing definitive causation.

Rebecca Kessler · Environmental Health Perspectives · Global

As interest in urban agriculture grows, researchers are working to manage the risks of contaminated urban soils. The focus is on maximizing the benefits of urban gardening while minimizing the potential hazards associated with soil contamination.

Robert Garey Stewart, Marcel Korth, Laurenz Langer, Shannon Rafferty, N Rebelo Da Silva · · Global

This paper is a protocol for a systematic review on the impacts of urban agriculture programs on food security and nutrition in low and middle-income countries. It notes potential disadvantages of urban agriculture, including contamination, spread of diseases, depletion of water supplies, soil erosion, and health risks from pesticides. The review aims to identify, appraise, and synthesize evidence on these impacts comprehensively and transparently, given that the existing evidence-base is not well understood.

Susana Olivares Reumont, Damarys García Céspedes, Lázaro Lima Cazorla, Israel Saborit Sánchez, Axel Llizo Casals, Pedro Pérez Álvarez · Revista Internacional de Contaminación Ambiental · Cuba (Havana)

This study investigated levels of Cu, Pb, Cd, and Zn in soils and vegetables from 17 urban agriculture farms around the "Calle 100" landfill in Havana, Cuba, during 2006-2007. Findings showed that 35% of soils exceeded typical Cuban agricultural ranges for Zn, and 52% for Pb. Critically, 23% of soils surpassed phytotoxic and international limit levels for Pb, and 12.5% of vegetable samples exceeded Cuban maximum permissible limits for Pb in food for human consumption. The results indicate a need for strict monitoring of horticultural crops in the area due to contamination.

Shazia Iram, Ayesha Zaman, Zaiba Iqbal, Rabia Shabbir · Polish Journal of Environmental Studies · Global

This study screened soil samples from peri-urban agricultural areas to investigate heavy metal contamination and identify heavy metal-tolerant fungi. Results showed that the majority of isolated fungi were resistant to lead (Pb) and chromium (Cr). Among the strains, Aspergillus niger was the most tolerant to Pb with an MIC of 600 mg/l, and Aspergillus flavus was the most tolerant to Cr with an MIC of 400 mg/l.

Kibassa, Kimaro, Shemdoe · Scientific Research and Essays · Tanzania (Dar es Salaam)

A study assessing heavy metal concentrations in soils from selected urban agriculture areas in Dar es Salaam, Tanzania, found that zinc, chromium, cadmium, lead, and copper levels in all six investigated sites were within the Tanzania Bureau of Standards permissible limits. The highest values for copper, zinc, and lead were observed in Tazara Mchichani, potentially indicating pollution from surrounding manufacturing industries. Flooding did not appear to influence the distribution of these heavy metals.

Ines Vlahović, Ksenija Karlović · Agronomski glasnik ·

A survey conducted from May to August 2011 examined the frequency of poisonous and allergenic plant species at nine educational institutions in the town of Samobor, Croatia — three kindergartens, four elementary schools, one high school and one library. The survey identified 15 poisonous plant species, represented by 182 specimens, and 17 allergenic plant species, represented by 129 specimens.

Ghulam Murtaza, Abdul Ghafoor, Muhammad Zia‐ur‐Rehman, Muḥammad Ṣābir, Asif Naeem · Communications in Soil Science and Plant Analysis · Global

This study investigated metal accumulation in plants grown in urban agricultural lands irrigated with untreated city effluent in developing countries. Sewage samples showed hazardous electrical conductivities, sodium adsorption ratios, and residual sodium carbonate for irrigation, although metal levels were near permissible limits. Critically, plants acquired metal contents that were greater than those found in the raw sewage or soils, indicating significant metal uptake.

Lori Leonard, W. J. S. Mwegoha, Charles Kihampa · International Journal of Plant Animal and Environmental Sciences · Tanzania (Dar es Salaam)

This study investigated public awareness and health risks from heavy metal pollution in vegetables irrigated with Msimbazi River water in Dar es Salaam, Tanzania. Over 71% of 35 respondents used the river for irrigation, and high levels of chromium, lead, and copper were detected in popular vegetables. 69% of respondents were unaware of industrial pollution, and 63% were unaware of potential health effects. The study found that 95.6% of adults, 30.7% of children aged 6-12, and 12.5% of children aged 2-6 were at risk of lead carcinogenic effects, while 5% of children aged 2-6, 2.8% of children aged 6-12, and 1.2% of adults were at risk from carcinogenic cadmium effects.

Aubin Ondo, Pascale Prudent, C. Massiani, Menye Biyogo, Mariane Domeizel, Jacques Rabier, François Eba · Journal of the Serbian Chemical Society · Gabon (Libreville)

An assessment of urban agriculture's impact on soil properties and metal uptake by leafy vegetables in Libreville, Gabon, found strong soil acidification and decreased nutrient/metal concentrations due to agricultural practices. Metal transfer to plants was significant, with amaranth accumulating more metals than other vegetables, though cadmium and lead were not detectable in plant tissues. Amaranth and roselle preferentially concentrated metals in their leaves.

Evaristo Mwaba Kapungwe · Indonesian Journal of Biotechnology (Universitas Gadjah Mada) · Zambia

This study investigated farming practices related to heavy metal contaminated wastewater irrigated farming in two peri-urban areas of Zambia: New Farm in Mufulira and Chilumba Gardens in Kafue. Data was collected by observing crop cultivation activities at field plots along transects in stratified land zones. The results revealed that farming practices were characterized by traditional land management and multiple cropping systems, influenced by agro-ecological factors and the availability of heavy metal contaminated wastewater, which has the potential to contaminate soils and crops.

Y. Niang, S. Niang, Saliou Niassy, Y Dieng, Mohamed Gaye, K. Diarra · International Journal of Biological and Chemical Sciences · Senegal

This study assessed the effect of wastewater on the agronomical performance and hygienic quality of tomato and lettuce in Senegal, comparing it to tap water, irrigation modes, and fertilizers. While tomato showed no pathogenic germs with wastewater, lettuce watered with wastewater via aspersion contained significantly more pathogenic germs than those watered in draining mode. Significant differences in yield and fruit size were observed between lettuce treated with tap water and wastewater.

Iwona Makuch · Soil Science Annual · Global

This study investigated the influence of intensive horticulture on lead content and its fractions in soil profiles from house gardens, allotment gardens, and arable fields. It was not determined that the manner of usage had any influence on total lead content or its distribution in soil profiles. However, the usage manner did influence the content and distribution of lead fraction III, which is connected with organic matter, with humus horizons of garden soils showing the highest content.

Mirelys Rodríguez Alfaro, Olegário Muñiz Ugarte, Bernardo Calero Martín, A. Álvarez, Francisco Martínez Rodríguez, Teudys Limeres Jiménez, Mercedes Orphee Montoya, Adriana M. de Aguilar Accioly · DOAJ (DOAJ: Directory of Open Access Journals) · Cuba

This study evaluated the heavy metal content of Cadmium, Lead, and Nickel in organic fertilizers (composts from urban solid waste) and substrates, and their effect on vegetables grown in organoponics in Havana and Guantánamo, Cuba. Composts obtained from unsorted urban solid waste and the substrates prepared from them were found to contain heavy metals, especially Cadmium and Lead, above maximum permissible limits. It was concluded that these products should not be used for food production, as these metals translocate to the edible parts of the cultivated vegetables.

Sally Brown, Ingrid Clausen, Mark A. Chappell, Kirk G. Scheckel, M. Newville, Ganga M. Hettiarachchi · Journal of Environmental Quality · Global

Against a background in which the safety of urban farming has been questioned because of possible contamination in urban soils, this study tested whether high-iron biosolids-based composts could reduce the bioaccessibility of soil lead (Pb) and arsenic (As), using two laboratory incubations and a field trial. Pb and As bioaccessibility were assessed with an in vitro assay, and changes in Pb, As, and Fe speciation were analyzed on select samples using micro-X-ray fluorescence mapping and micro-XANES. A compost with iron added to wastewater-treatment residuals (Fe WTR compost), applied to soil at 100 g/kg, decreased Pb bioaccessibility in both laboratory incubations, though results for As were mixed. In contrast, the composts tested in the field trial (with iron added as Fe powder or FeCl) did not reduce bioaccessible Pb and showed only limited reductions in bioaccessible As; these same composts also had no effect on Pb bioaccessibility in the second laboratory incubation. The study concludes that high-iron biosolids compost is effective at reducing Pb accessibility only for certain types of iron-rich materials.

R. Plant, Jeremy Walker, Scott Rayburg, J Gothe, Teresa Leung · Australian Geographer · Australia

A study of the Hawkesbury-Nepean River in Sydney, Australia, examines the effects of pesticide use by the small-scale horticulturalists supplying the city's fresh vegetable markets on aquatic biodiversity. Through interviews with actors across the institutions responsible for agriculture, water quality, and environmental protection, it assesses the effectiveness of pesticide governance in the Greater Sydney Basin. It finds that pesticide pollution is rarely measured or monitored and is not a priority for any particular agency, meaning the pollution remains effectively uncontrolled. The study concludes that although public health, the long-term viability of local farming, and the ecological health of the river are compatible goals, they currently exist under a system of "organised irresponsibility."

Leigh Whittinghill, D. Bradley Rowe · Renewable Agriculture and Food Systems · Global

Urban agriculture faces limitations including competition for space, lack of formalized land use rights, and health hazards from food contamination. Green roof technology is proposed as a method to alleviate these issues, potentially reducing the use of contaminated land and water at ground level. However, for large-scale implementation, installation costs must be reduced, roof weight limitations assessed, and appropriate management practices developed.

L Ndiaye M, Y Dieng, S. Niang, Rak H, Mauro Tonolla, Raffaele Peduzzi · African Journal of Microbiology Research · Senegal (Dakar)

A survey in Dakar, Senegal, assessed the effect of irrigation water quality on Salmonella spp. incidence in lettuce. Microbiological analysis revealed that 35% of irrigation water was contaminated by Salmonella spp., with no significant difference between groundwater and wastewater. Lettuce from Dalifort and Grand-Yoff markets showed significantly higher contamination rates than those from Sham and Zinc markets. The study concluded that irrigation water and manure are potential sources of contamination, and lettuce may serve as a vector for pathogen transmission to consumers.