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.

Brent F. Kim, Melissa N. Poulsen, Jared D. Margulies, Katie L. Dix, Anne Palmer, Keeve E. Nachman · PLoS ONE · United States (Baltimore, Maryland)

This study characterized urban community gardeners' knowledge and perceptions of soil contaminant risks in Baltimore, Maryland, United States, through surveys with 70 gardeners from 15 gardens and interviews with 18 key informants. It found low levels of concern and inconsistent knowledge regarding heavy metal and organic chemical contaminants among gardeners. Furthermore, barriers to investigating garden site history and conducting soil tests, along with limited knowledge of best practices for reducing exposure, were identified.

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.

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.

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.

Dieudonné E. Musibono, E.M. Biey, M. Kisangala, Camille Ipey Nsimanda, B.A. Munzundu, V. Kekolemba, J.J Palus · VertigO · Democratic Republic of Congo (Kinshasa)

Urban agriculture in Kinshasa, Democratic Republic of Congo, serves as a palliative solution for social survival constraints such as a lack of remunerative salaries and sustainable jobs. However, poorly supervised urban farmers cultivate along busy roads, exposing vegetables to various contaminations, including lead. This practice highlights issues with site selection and supervision.

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.

Kohei Makita, Eric M. Fèvre, Charles Waiswa, Mark Bronsvoort, Mark C. Eisler, Susan C. Welburn · Land Use Policy · Uganda

This paper describes a spatial representation of the peri-urban interface (PUI) of Kampala, Uganda, and identifies socio-economic factors related to peri-urbanicity using rapid rural mapping. It notes that urban and peri-urban agriculture (UPA) in rapidly expanding cities carries public health risks, such as zoonotic disease transmission. The study provides a methodology for describing the PUI in developing countries.

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.

Shahzad Kouser, Mr. Abedullah, Abdus Samie · The Pakistan Development Review · Pakistan (Faisalabad)

This study, conducted in 2006 with 200 farmers in two peri-urban villages of Faisalabad, Pakistan, estimated the economic values of negative health externalities from wastewater use in cauliflower production. While wastewater use appeared profitable without considering externalities, factoring in health costs strongly discouraged its use. The health externalities for a three-month cauliflower crop on 741 acres amounted to Rs 3.2 million, and for 5,283 acres of vegetables cultivated with wastewater in Faisalabad, the annual total was Rs 90.7 million. The findings indicate a significant economic loss due to wastewater use, suggesting that installing a water treatment plant is a viable option to minimize these external effects.

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.

Stephanie Buechler, Gayathri Devi Mekala, B. Keraita · Victoria University Research Repository (Victoria University) · Global

This 2006 global study from Victoria University discusses wastewater use in urban and peri-urban agriculture for crop production and aquaculture, noting its role in generating livelihoods and providing cheap produce. However, the study emphasizes that clear policy guidelines and careful research are needed to prevent potential negative impacts on human health and the environment from wastewater reuse.

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.

Samantha Langley-Turnbaugh, David E. Wilkinson, D. Rocque · Soil Survey Horizons · United States

This study characterized urban soils in a low-income neighborhood of Portland, Maine, that was heavily industrialized in the late 1800s, examining seven pedons for particle size, cation exchange capacity (CEC), base saturation, exchangeable bases, pH, and trace elements (Pb, Cr, Cu, Co, Cd, Ni, Zn, Hg, Ti, Zr). The soils contained numerous artifacts and showed a high degree of horizontal and vertical spatial variability; several trace elements were present at elevated levels, with lead (Pb) the dominant metal in surface horizons (600 mg/kg), and many metals correlated with each other and with iron and aluminum, and some with clay content and pH, though the study concludes that mapping soil units by specific trace element ranges would be difficult given the extreme variability observed.

Tanja Pless‐Mulloli, Vivienne S. Air, Catherine Vizard, Ian Singleton, D. L. Rimmer, Philip Hartley · Epidemiology · United Kingdom

A study in an urban, industrial allotment site in the UK's northeast assessed the potential for public health impact related to soil contamination by taking 86 soil samples and analyzing vegetables and eggs. All 18 initial soil samples exceeded UK guidelines for lead (median 869 mg/kg) and arsenic (median 40 mg/kg), and widespread contamination with PCDD/F was also found. Despite high soil contamination, the uptake of lead and arsenic into vegetables and eggs was low, and these were not deemed major exposure pathways.

Jianguo Dai · Journal of Shenzhen Polytechnic · China (Shenzhen)

Urban agriculture in Shenzhen faces problems including decreasing farmland, inadequate skilled farmers, poor disaster resistance, immature insurance, increasing contamination of water, soil, air, and agricultural products, and poor modern enterprise management. Strategies proposed for sustainable development include specific laws, pollution protection, education, research, technology application, industrial technology application, leisure agriculture development, and diversification.

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.

Tanja Pless‐Mulloli, Karen L. Foster, J Bush · Epidemiology · United Kingdom (Newcastle upon Tyne)

Investigations in Newcastle upon Tyne, UK, analyzed the extent and consequences of disposing 2000 tons of incinerator ash on over forty allotments. Soil, egg, and vegetable samples (75 soil, 21 egg, 65 vegetable) revealed contamination of footpaths with dioxin/furan (max 9000 ng/kg I-TEQ) and high levels of copper, lead, and zinc. Mean dioxin/furan levels in soil were 38 ng/kg I-TEQ and in eggs were 16.4 ng/kg I-TEQ, indicating significant contamination and potential exposure pathways for allotment gardeners and children.

Bernard Keraita, Pay Drechsel, Philip Amoah · Environment and Urbanization · Ghana (Kumasi)

This study in Kumasi, Ghana, investigated the influence of urban wastewater on stream water quality and peri-urban agriculture through interviews and water quality assessments. It found that population increase and underinvestment in sanitation facilities led to large volumes of untreated wastewater entering streams. High levels of faecal coliform were recorded in the city's streams, downstream areas, and on vegetables sold in Kumasi’s markets due to contaminated wastewater.

Nigel Poole, DS Bhupal, Fiona Marshall, Dolf te Lintelo · · India

New knowledge is presented on the impacts of urban and peri-urban (UPU) environmental pollution on food safety attributes of vegetable marketing systems in India. Air pollution reduces crop yield and nutritional quality, and is a major source of particulate contaminants that accumulate at toxic levels in edible crops. The study explores the balance between public and private quality assurance initiatives and identifies wholesale markets as a potential entry point for quality assurance.

L.M. van den Berg · WIT transactions on ecology and the environment · Africa, Asia

Urban agriculture, despite severe competition for space, plays roles such as fresh food supply, leisure, supplementary income for the urban poor, and green space management. Case studies in Africa and Southeast Asia demonstrate the difficulty of maintaining these roles due to public health and environmental degradation concerns. Urban agricultural producers may rely on polluted streams for irrigation, cause soil erosion through inappropriate farming techniques, or poison surrounding residents with pesticides. The paper suggests that urban agriculture could be more beneficial to the urban system if treated by town planners as a normal urban function requiring both regulation and protection.