Research & reports

Abdallah Zacharia, Wajihu Ahmada, Anne H. Outwater, Billy Ngasala, Rob Van Deun · The Scientific World JOURNAL · Tanzania

This cross-sectional study, conducted from February to August 2018, evaluated three waste stabilization ponds (WSPs) in the Morogoro, Mwanza and Iringa regions of Tanzania, where treated effluent is used for urban agricultural activities despite the disease-transmission risks posed by untreated or partially treated wastewater. Using APHA physicochemical methods, the modified Bailenger method and Ziehl-Neelsen staining for parasites, and membrane filtration for fecal coliforms (FC), analyzed with SPSS version 20, the study found helminth egg removal ranging from 80.8% to 100% and protozoan (oo)cyst removal from 98.8% to 99.9%, with the Mwanza WSP showing the highest FC reduction (3.8 log units per 100 mL). Both parasites and FCs in the effluents of the assessed WSPs were found at concentrations exceeding World Health Organization and Tanzania Bureau of Standards limits, except for helminths in the Morogoro WSP and FCs in the Mwanza WSP. FC counts correlated significantly with protozoa (p<0.01) and predicted protozoa occurrence well (p=0.011), with correlations also found among physicochemical parameters, parasites and FC bacteria. The study attributes the systems' inadequate performance to a lack of regular maintenance and/or operation beyond capacity, and concludes that FC indicators are a reasonable proxy for monitoring protozoa but not for helminths, which should be surveyed independently.

Dan Li, Chun Hong Wong, Mei Fang Seet, Nicole Kuan · Frontiers in Microbiology · Singapore

This study conducted, for the first time to the authors' knowledge, an investigation of Stenotrophomonas maltophilia -- an emerging opportunistic pathogen capable of causing high-mortality nosocomial infections in immunocompromised patients while also being ubiquitous in the environment -- on leafy green vegetables and in a hydroponic farming facility in Singapore. Eleven isolates were recovered from three vegetable types (sweet basil, kale, parsley) and the nutrient solution, with high population levels reached in vegetables under abused storage temperatures (over 8-log CFU/ml in basil juice after six days at 20°C) and on hydroponic facilities through biofilm formation (8 to 9-log CFU/well), and UV treatment (over 4-log reduction at 250 mJ/cm²) was identified as an effective measure to reduce contamination in nutrient solutions and facilities.

Anne Barbillon, Christine Aubry, Nastaran Manouchehri · HAL (Le Centre pour la Communication Scientifique Directe) · France

This French guide, "R.E.F.U.G.E.," developed by AgroParisTech, sets out a four-step methodology to help urban-planning actors in the Île-de-France region assess and manage soil contamination risk before establishing urban agriculture on available land: a historical and environmental site study, a sampling strategy, interpretation of soil analyses, and, where warranted, a formal health risk assessment. Based on France's national methodology for managing polluted sites and soils, it is intended as a first harmonized technical tool for the field and was slated for a testing phase applying it to future urban agriculture projects. The abstract itself does not report contamination measurements or findings from any specific site; it describes the assessment procedure rather than presenting soil contamination data.

Timo Falkenberg, Deepak Saxena · Indian Journal of Community Medicine · India (Ahmedabad)

A 12-month case-cohort study of 187 households in four communities of Ahmedabad, India, purposively selected by irrigation water type (groundwater, surface water, wastewater), with bimonthly self-reported health diaries and most-probable-number measurement of Escherichia coli in water. Mean E. coli concentrations per 100 mL were 3.04×10^4 (groundwater), 9.28×10^5 (surface water) and 4.02×10^9 (wastewater) — all exceeding international irrigation water standards. Diarrhoea incidence was 7.92 episodes per 1000 person-weeks in the groundwater area versus 13.1 (wastewater) and 13.4 (surface water), with a positive correlation between irrigation water quality and diarrhoea. Wastewater reuse is often promoted as a water-scarcity fix for urban agriculture; this study shows it carries a health cost borne by the farming households themselves.

Martin Dawson, Mike Hutchins, Nuria Bachiller‐Jareno, Steven Loiselle · Freshwater Science · United Kingdom (London)

A citizen-science study from 2014 to 2016 assessed water quality in a 5.6-ha urban community garden in southwestern London, using borehole water. Measurements of specific conductance and tryptophan-like fluorescence were taken over 28 months. The study found no evidence of external contamination sources or temporal changes in water quality. However, significant variations in water quality between boreholes were directly linked to on-site manure storage and use, and local geological conditions.

Camille Frazier · Journal of Political Ecology · India (Bengaluru)

This article examines the motivations and practices of organic terrace gardeners (OTGians) in Bengaluru, India, who grow food in private spaces. While OTGians successfully create a vibrant community driven by food safety and environmental concerns, their efforts are limited to the middle class due to class-specific concerns and production practices. The study highlights that urban gardening in this context remains an intervention primarily for the middle class.

Joseph Chabi, Miracle C. Eziefule, Rebecca Pwalia, Joannitta Joannides, Dorothy Obuobi, Godwin Amlalo, Charlotte Addae, Alidu Iddrisu, Dominic Acquah-Baidoo, Samuel Akporh, Sampson Gbagba, Kwadwo K. Frempong, Melinda P. Hadi, Helen Pates Jamet, Samuel Dadzie · Advances in Entomology · Ghana

This study in Accra Metropolis, Ghana, compared Anopheles gambiae s.l. species composition and insecticide resistance between two vegetable-growing and two non-vegetable growing areas. All A. gambiae s.l. populations tested were resistant to five insecticides, with lower mortalities observed in vegetable-growing areas (e.g., 2.6% and 12.5% for deltamethrin) compared to non-vegetable areas (36.2% and 38.9%). Anopheles gambiae s.s. and Anopheles coluzzii were dominant in vegetable-growing areas. The findings indicate that urban agriculture contributes to the development of insecticide resistance, which needs consideration in vector control strategies.

Mohamad Assad, Michel Chalot, Fabienne Tatin‐Froux, Valérie Bert, Julien Parelle · Journal of Environmental Quality · Global

This study investigated element transfer in edible crops (cucumber, pepper, cabbage, lettuce) and poplar (Skado cultivar) grown on soils contaminated with sediments dredged from water canals in the 1960s, aiming to develop a biomonitor. The results showed accumulation of cadmium (Cd) and zinc (Zn) in the edible parts of crops, particularly leafy vegetables, indicating that Cd could be ingested in amounts reaching the tolerable daily intake (TDI) in this context. No accumulation of lead (Pb) was detected.

Walter W. Furness, Courtney M. Gallaher · Local Environment · United States (Rockford)

A study in Rockford, Illinois, examined community gardens to assess their contribution to residents' access to fresh produce and other social benefits. Data was collected through interviews with gardeners, focus groups, and surveys of food pantry users. The findings indicate that while non-gardening community members benefit from increased produce provided by the gardens, they do not receive all the social and communal benefits associated with active garden participation.

P.S. Bouda, Edmond Hien, A. Dioma, Hyacinthe Kambiré, Yacouba Maïga, Der Adolphe Somé, Sylvie Nazaret, A.S. Ouattara · DOAJ (DOAJ: Directory of Open Access Journals) · Burkina Faso

A study in Ouagadougou sub-urban agricultural fields, Burkina Faso, assessed the impact of using untreated Solid Urban Wastes (SUW) as agricultural fertilizers on soil properties and crop production. SUW amendment significantly increased pH, total C, N, P, and available P, and maize height and biomass yield were 124% and 164% higher in amended plots, respectively. However, trace metal elements (Cu, Zn, Pb, Ni, Cr) concentrations were higher in amended fields, indicating that urban waste carries contaminants posing public health risks.

Salvatore Engel‐Di Mauro · Gender Place & Culture · Global

This study discusses two concerns regarding urban community gardens' political potential, suggesting caution. It notes that the community in urban community gardens can be reactionary and capitalism-friendly, potentially impeding the collectivization of social reproduction if it remains largely women's work. Additionally, urban gardeners, primarily women, people of color, and the elderly, may face exposure to toxic substances and increased care work needs due to health effects.

Zane Vincēviča–Gaile, William Hogland, Māra Stapkēviča, Juris Burlakovs · Linnaeus Eco-Tech · Latvia

This study investigates the transfer of metallic elements in the soil-plant segment of the food chain through laboratory and field experiments. It also includes a quantitative analysis of food samples from Latvia, including fruits and vegetables from Riga city allotment gardens, to identify element composition and potential contamination risks from urban pollution. Results of experiments and analyses revealed the influence of factors such as seasonality, botanical origin, site-specific factors, agricultural practice, and food processing on element transfer.

Cécile Le Guern, Liliane Jean‐Soro, Béatrice Bechet, Thierry Lebeau, Dorine Bouquet · Land Degradation and Development · France

Urban allotment gardens in Nantes, France, were found to have soil contamination, with lead (Pb) levels ranging from 100–400 mg kg−1, posing health risks. Local actors collaborated to characterize soil, evaluate sanitary risks, and discuss management options. The most frequent solution was replacing polluted soils with clean soils, while other strategies included on-site management of excavated soil, non-accumulative cropping, or changing land use.

St Clair, Rebecca, Hardman, Michael, Adams, David, Armitage, Richard, Barry, Veronica, Larkham, Peter, Sherriff, Graeme · Research Explorer (The University of Manchester) · United Kingdom

This paper reviews the diversity of urban agriculture (UA) activities in England, from small-scale guerrilla gardening to large community projects. It suggests that UA is under-theorized, with previous research focusing on practicalities and activism. The paper highlights UA's problematic contribution to food production and warns of the 'local trap'.

Jonas Aleixo da Silva · · Brazil

This qualitative case study analyzed urban agriculture practices in the Mangueira neighborhood, Grajau-MA, Brazil, through visits, observations, and interviews. The study found that while urban horticulture provided benefits like income and product quality, it faced difficulties including reliance on borrowed land, soil depletion, and the use of agrochemical products, indicating that production was not free from chemical fertilizers.

Piotr Krzyk, Bogusława Kwoczyńska · Problemy Drobnych Gospodarstw Rolnych / Problems of Small Agricultural Holdings · Poland (Cracow)

This study quantitatively assessed the conversion of agricultural land to investment purposes in Cracow's Mogiła and Wyciąże neighborhoods from 2010-2013, based on local plans. It also addressed soil quality, heavy metal content, and pH. Analysis of spatial management plans for these areas indicated a systematic decline in the share of biologically active areas.

Amina Abubakari, John Asiedu Larbi, Robert Clement Abaidoo · Journal of Tropical Diseases · Ghana (Kumasi)

A 2018 study in Kumasi, Ghana, assessed 7017 health facility data from 77 communities to investigate malaria transmission in areas with wastewater irrigation. It found approximately 3698 malaria cases in wastewater irrigation areas and 3319 in areas without, with a P-value of 0.1914, indicating no statistically significant difference. However, Anopheles spp. mosquito densities were high in furrows, followed by ponds, suggesting that anthropogenic activities related to urbanization and wastewater irrigation may contribute to malaria transmission.

Jendayi Jones · Knowledge@UChicago (University of Chicago) · United States (Chicago)

This project uses interviews and literature research to examine the state of urban agriculture in Chicago and its potential to address nutritional inequity, unemployment, and community building. By analyzing two policy initiatives, two land management organizations, and three interviews, the study aims to identify effective aspects and areas needing improvement in Chicago's urban agriculture setup.

Jenny Smart, David Tschirley, Francis Smart, Smart, Jenny Cairns, Tschirley, David, Smart, Francis · AgEcon Search (University of Minnesota, USA) · Mozambique

Food system transformation and changes in diet quality were assessed in Mozambique amidst rapid urbanization and income growth. Rising incomes and processed food consumption were found to be associated with a worsening of negative dietary factors. Furthermore, urbanization, controlling for income, was more strongly associated with a worsening of negative factors than an improvement in positive dietary factors. However, owning one's own farm had a positive and significant effect on nutrition for urban households, primarily driven by reduced purchases of unhealthy foods.

Arlinda Sheqiri, Parna Rastgo · Journal of Environmental Science and Engineering - A · Europe

A study on the use and value of green school grounds in developing countries was conducted across five schools in Podujevo, Kosovo. The findings revealed that the potential of green school grounds in most studied cases has not been utilized. Opportunities provided by the municipality and environmental NGOs are insufficient, suggesting a need to rethink the design and use of green school grounds in developing countries.

Timo Falkenberg, Deepak Saxena, Thomas Kistemann · The Science of The Total Environment · India (Ahmedabad)

A cohort study investigated the contribution of wastewater irrigation to in-household water contamination among urban farming households in Ahmedabad, India, within the context of WASH (Water, Sanitation, Hygiene). Drinking water samples from 204 households were collected four times over 12 months, and E. coli was quantified. Significant positive differences in water quality between point-of-source and point-of-use samples were identified in 78% of households. During the monsoon, the peak of contamination, only 6% of households had access to safe drinking water at the point-of-use. Wastewater irrigation showed an adverse effect on in-household water contamination, with an effect size larger than the mitigation effect of access to sanitation or personal hygiene.

Sky Roberts, Charlie M. Shackleton · Land · South Africa

This study investigated urban community food gardens in four towns in South Africa, using surveys and GIS analysis over three decades. It found that common motivations included cash poverty (37%) and the need to grow food (34%), with reported benefits such as a healthy lifestyle (58%) and food consumption (54%). A significant challenge was theft of garden infrastructure or produce, and there were declines in the number and area of urban community gardens, with only 16% of gardens from the 1980s still operating in the 2000s.

John Misenheimer, Clay Nelson, Evelyn Huertas, Myriam Medina-Vera, Alex Prevatte, Karen D. Bradham · Geosciences · Puerto Rico

Total and bioaccessible arsenic (As) and lead (Pb) levels, and their uptake by 10 commonly grown garden plants, were examined in three urban community gardens in Puerto Rico. Total As ranged from 2 to 55 mg/kg and Pb from 19 to 172 mg/kg in soils. Leaves accumulated higher concentrations of As and Pb than edible flesh, with culantro leaves showing the highest concentrations (3.2 mg/kg dw As, 8.9 mg/kg dw Pb).

Sugandhi del Canto, Rachel Engler‐Stringer · Policy Press eBooks · Global

Restrictive covenants, a corporate real estate practice, are identified as a significant barrier to establishing new food stores in older neighborhoods globally. These covenants place conditions on land use, such as prohibiting food sales or grocery store development, making it harder to address existing nutrition deserts. Government support is needed to limit these covenants and develop alternative food channels, including urban agriculture.

Mireia Ercilla‐Montserrat, Pere Muñoz, J.I. Montero, Xavier Gabarrell, Joan Rieradevall · Journal of Cleaner Production · Spain (Barcelona)

This study measured heavy metal content in air and hydroponic lettuce leaves at four sites in Barcelona, including high-traffic areas, to assess potential contamination from atmospheric pollution. The results showed that heavy metal concentrations in lettuce leaves were below EU-legislated limits in all cases, and air concentrations were less than 50% of legislative limits. The study concluded that Barcelona's air heavy metal content is low and not a source of contamination for urban crops, even near high-traffic areas.