Research & reports

Hyuck-Soo Kim, Young‐Nam Kim, Jin‐Won Kim, Kye-Hoon Kim · 한국토양비료학회지 · South Korea (Seoul)

This study investigated the properties and total and phytoavailable contents of heavy metals (Cd, Pb, Cu, Zn) in 21 urban agricultural soils in Seoul, South Korea. The total heavy metal concentrations in the examined urban agricultural soils were found to be lower than the warning levels for area 1 according to the Soil Environmental Conservation Act of Korea. Phytoavailable-Cu, -Pb, and -Zn concentrations were also reported as 0.02-0.28, N.D-0.09, and 0.01-0.43 mg/kg, respectively.

Hillary Anne Doerfler · D-Scholarship@Pitt (University of Pittsburgh) · Global

A literature review examined the use of school garden programs for health promotion among elementary school youth. The review found that school gardens successfully improved academic achievement, increased fruit and vegetable consumption, and enhanced social skills. However, significant barriers to implementation were identified, particularly in low socioeconomic status schools, including a lack of funding, insufficient gardening knowledge among teachers, and limited community and parent involvement.

I Kibona, SL Mkoma, IC Mjemah · International Journal of Biological and Chemical Sciences · Tanzania (Morogoro)

Groundwater samples were collected from 20 wells in six wards of Morogoro municipality, Tanzania, during March-April 2010, and nitrate concentrations were measured. Nitrate levels ranged from 1.4 mg/L to 32.5 mg/L, with an average of 7.76 mg/L. These concentrations were below the upper limits set by the Tanzania Bureau of Standards and the World Health Organization.

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.

Sinan Koont · University Press of Florida eBooks · Cuba

An assessment of Cuban urban agriculture's production and distribution outcomes finds that the most successful subprogram is fresh vegetable production, which has grown rapidly island-wide, while other subprograms remain active but less developed. Distribution occurs through thousands of points-of-sale, MALs, self-provisioning, and MAEs, with social consumption at workplaces, hospitals, and schools. Urban agriculture plays a significant role in improving Cuban diets but has not led to food sovereignty; other outcomes cited include employment generation, environmental benefits, and community building.

Haruna Haruna · · Africa

A study of soils irrigated with sewage water on Fadama floodplain land in northern Nigeria used sequential extraction to determine the mobility and availability of cadmium, copper, nickel, lead and zinc. The residual fraction held the largest pool of all five metals, but 2.7-70.2% was present in the potentially available, non-residual fraction. Contamination by cadmium and nickel was less severe than by lead, copper and zinc, and mobility/bioavailability ranked Pb > Zn > Cu > Ni > Cd.

Barbara Matthys, Benjamin G. Koudou, Eliézer K. N’Goran, Penelope Vounatsou, Laura Gosoniu, Moussa Koné, G. Gissé, Jürg Utzinger · Annals of Tropical Medicine and Parasitology · Côte d'Ivoire (Abidjan)

Two surveys were conducted in market gardens of Abidjan, Côte d'Ivoire, during the rainy and dry seasons to identify mosquito breeding habitats. The study found that urban agriculture areas may lead to higher densities of mosquito breeding sites, with "agricultural trenches" between seedbeds being the most likely sites to be positive for Anopheles larvae and mosquito pupae.

Zhou Pei · · China (Shanghai)

A study conducted in Orchard Village, Nanhui District, Shanghai, from July to September 2009, investigated the effects of phosphorus non-point source pollution on groundwater in an urban agricultural region. Total phosphorus concentrations averaged 1.31 mg/L and phosphate concentrations averaged 0.42 mg/L, with phosphate significantly exceeding the V class surface water standard (0.4 mg/L), rendering the water unsuitable for drinking. Phosphorus non-point source transport was linked to land-use types, with phosphorus content near orchards changing with increased rainfall, and farmland phosphorus loss accelerating with runoff, fertilization, and water leach.

Mamadou Ndiaye, H.‐R. Pfeifer, S. Niang, Y Dieng, Mauro Tonolla, Raffaele Peduzzi · VertigO · Senegal (Dakar)

In Dakar's urban agriculture, untreated wastewater is used for irrigation due to shallow groundwater salinization. A study conducted at Pikine and Patte d'Oie sites evaluated the chemical and microbiological quality of irrigation water. Findings showed that total nitrogen in irrigation water exceeded WHO guideline values, Salmonella spp. was isolated from 35% of irrigation water, and a wastewater sample tested positive for Vibrio cholerae. This research indicates that irrigation with polluted water and the use of organic fertilizers can degrade groundwater quality and pose health risks.

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.

Andrew Flachs · Electronic Green Journal · United States

This paper explores the social and cultural effects of urban gardening in the greater Cleveland area, noting that the social impact of community gardens is less studied than other benefits. The author's fieldwork found that many gardeners combine utilitarian functions with environmentalist ideology, contrary to some authors who claim that gardeners are preoccupied with economic impact, leading to a biased conclusion about motivations. The paper aims to convey the complexity of use, function, and intent in these communal spaces.

Hygin Faust Kakai, Alban Gilles Kakai, Armelle Grey Tohouegnon · VertigO · Benin (Cotonou)

This study in Benin examined urban agriculture and waste valorization in Cotonou, Abomey, and Abomey-Calavi. In Cotonou, overexploitation of sandy, organic-poor soil in market gardening led to soil impoverishment, forcing gardeners to use chemical fertilizers with negative environmental impacts. However, some market gardeners adopted compost use, transitioning to organized organic urban agriculture after a waste management project supported waste valorization. This dynamic was not observed in Abomey, where urban agriculture is practiced in family spaces and public areas, unlike Cotonou's developed sites. Abomey-Calavi, despite rapid demographic growth, was almost devoid of urban agriculture practices.

Laura Whitzling, Michelle M. Wander, Ellen Phillips · Journal of Agriculture Food Systems and Community Development · United States (Chicago)

This study profiled soil quality, including lead levels, in 10 Chicago community gardens, comparing raised beds to non-raised beds and adjacent bare soil. The overall mean soil lead level was 135 ppm (n=86) by EPA method, with a range of 10-889 ppm. While most gardens' lead levels were not a concern, higher lead in adjacent bare soil suggested contamination risk. Use of raised beds reduced lead levels, but further study is needed.

Xiaona Li · Nongye huanjing kexue xuebao · China

A study measuring dioxin-like compound (PCDD/Fs) concentrations in 23 surface soil samples collected from different areas of Baiyin City, China, using HRGC/HRMS (high-resolution gas chromatography/high-resolution mass spectrometry). The concentration range of 2,3,7,8-PCDD/Fs was 0.42-8.56 pg I-TEQ/g, averaging 2.28 pg I-TEQ/g. By land-use type, concentrations averaged 3.37 pg I-TEQ/g in industrial areas, 1.31 in urban areas, 1.01 in agricultural areas, and 0.85 in background areas, following the order industrial > urban > agricultural > background. Higher-chlorinated isomers were the dominant contributors to total toxic equivalency (TEQ) in most samples.

Mamadou Ndiaye, S. Niang, H.‐R. Pfeifer, Raffaele Peduzzi, Mauro Tonolla, Y Dieng · Irrigation and Drainage · Senegal

Lettuces grown at two urban agricultural sites (Pikine and Patte d'Oie) near Dakar, Senegal, and sold in local markets were tested for microbial contamination linked to irrigation water. Salmonella spp. positivity was 6% at Pikine and 7% at Patte d'Oie farm sites, with lettuces irrigated by shallow 'Ceanes' groundwater most contaminated at both sites (8%), compared to wastewater irrigation (4% at Pikine) and well water (5% at Patte d'Oie); at market, Salmonella was isolated at every marketplace surveyed, with higher rates around Patte d'Oie (9% at Grand Yoff, 11% at Dalifort) than around Pikine (4% at Zinc, 2% at Sham) or the control site Rufisque (2%), and lettuces washed with Ceanes water before sale were more contaminated than those rinsed with tap water. Reusing wastewater for irrigation is presented as an alternative to animal manure, with the microbial contamination risk significantly reducible by washing vegetables with tap water before sale.

G. M. Hettiarachchi, Sabine Martin, A. David Rae, Phillip P. Defoe, Dennis Presely, G. M. Pierzysnki · · United States

Using a newly established urban community garden in Kansas City as a case example, this study examines the challenges of converting brownfield sites — abandoned or underutilized properties where environmental concerns impede redevelopment — into community gardens. Soil at the site was found to contain mildly elevated levels of lead (Pb) and detectable levels of DDT/DDE (an organochlorine pesticide). Based on an evaluation of soil properties, safety and corrective measures were proposed and implemented to reduce both direct (soil-to-human) and indirect (soil-to-plant-to-human) exposure for gardeners and their children, and field test plots with three crop types showing different contaminant-uptake patterns were established to evaluate site-specific soil amendments for reducing lead bioavailability.

Chandra Sen · Journal of Interdisciplinary Economics · India

This study estimated the impact of air pollution on crop yields in peri-urban areas of Varanasi, India. Phytotoxic gases are known to cause major yield reductions in important crops in developing countries, and in this study all major crops grown in peri-urban Varanasi — paddy, pigeon pea, maize, wheat, and potato — showed yield reductions attributable to air pollution. Air pollution was found to reduce both the yield and the nutritional quality of the produce, and the study calls for similar validation studies in other cities and for efforts to reduce air pollution in the city to improve crop yield and quality.

Cezary Kabała, T. Chodak, L. Szerszeń, Anna Karczewska, Katarzyna Szopka, Urszula Fratczak · Fresenius environmental bulletin · Poland (Wroclaw)

An analysis of 180 allotment garden soils in Wroclaw, Poland, found that concentrations of Cu, Pb, and Zn (12.5-659 mg Pb kg-1, 38.1-2103 mg Zn kg-1, 12.9-595 mg Cu kg-1) were influenced by industrial pollution sources, organic matter, pH, and macronutrients. Soils in gardens on former housing or industrial areas had significantly higher metal concentrations. Up to 35% of soils in the city zone were excessively contaminated, making them unsuitable for vegetable and fruit production and requiring reclamation.

M.R. Gorham, Tina M. Waliczek, Amy Snelgrove, Jayne M. Zajicek · HortTechnology · United States (Houston)

A pilot study in Houston, Texas, investigated the impact of 11 established community gardens on property crime numbers using 2005 crime data. Statistical comparisons between community garden areas and randomly selected city areas showed no statistically significant differences in the mean number of crime occurrences. The presence of a community garden was not found to be a predictor of a lower crime rate for a neighborhood.

Wendy Heiger‐Bernays, Alexa Fraser, Vaughn R. Burns, Kerry Diskin, David Pierotti, K Merchant-Borna, Michael D. McClean, Daniel J. Brabander, H. Patricia Hynes · PubMed · United States

A study characterized urban community garden soils contaminated by timbers, specifically finding elevated levels of polycyclic aromatic hydrocarbons (PAHs) from railroad ties and arsenic from chromated copper arsenate (CCA) treated lumber. Researchers determined the extent of contamination, designed a remediation plan, and assessed the safety of adding city compost as a soil amendment in Boston community gardens. Recommendations for healthful gardening practices were also provided.

W. Van Averbeke · Water SA · South Africa (Pretoria)

This study in five informal settlements of Atteridgeville, Pretoria, South Africa, used a pilot study, household survey, and multiple case studies to assess urban farming's contribution to food security and household income. While over half of households participated in urban farming, its contribution to total household income and food security was generally modest. Main constraints included lack of space and limited access to irrigation water.

Pay Drechsel, Liqa Raschid-Sally, Robert Clement Abaidoo · · Ghana (Accra)

Urbanization in West Africa has led to most domestic wastewater contaminating surface water sources. In Accra, Ghana, vegetables on urban markets are highly contaminated, with about 200,000 urban dwellers consuming street food containing raw vegetables from these sources daily. This research explores on-farm risk mitigation options, finding potential to significantly reduce helminth egg counts and bacterial contamination through improved washing practices.

Rodrigue V.C. Diogo, Andreas Buerkert, Eva Schlecht · Nutrient Cycling in Agroecosystems · Niger (Niamey)

This 24-month study investigated nutrient efficiency and food safety in urban and peri-urban agriculture in Niamey, Niger. Nutrient inputs and offtakes were quantified for 10 vegetable gardens and 9 millet fields, and contamination of irrigation water and selected vegetables with fecal pathogens and heavy metals was determined. Above-threshold levels of Salmonella spp. and Escherichia coli were detected in lettuce irrigated with river water and fertilized with animal manure, and in lettuce irrigated with wastewater, indicating food safety concerns.

Anges Yadouléton, Alex Asidi, Rousseau F Djouaka, B. James, Christian Agossou, Martin Akogbéto · Malaria Journal · Benin

A study in urban areas of Benin investigated the impact of rapid vegetable farming development on the emergence of insecticide resistance in Anopheles gambiae populations, using sociological data, bioassay tests, and biochemical analysis. The expansion of urban agriculture led to improper insecticide use for vegetable pests, exerting strong selection pressure on mosquito larval populations. This resulted in the emergence of insecticide resistance in malaria vectors, with permethrin mortality rates of 76% in Parakou, 23.5% in Porto-Novo, and 17% in Cotonou.

Daniela Plachá, Helena Raclavská, Dalibor Matýsek, Mark H Rümmeli · Geochemical Transactions · Czech Republic

Polycyclic aromatic hydrocarbon (PAH) contamination was investigated in urban, agricultural, and forest soil samples from the surroundings of Valasske Mezirici, Czech Republic. While PAH levels in urban/agricultural soils were within the typical range for industrialized areas, forest soils showed elevated PAH concentrations compared to other forest soils in Western and Northern Europe. PAH concentrations were highest in localities at higher altitudes and decreased with increasing distance from the town.