Research & reports

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).

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.

Muhammad Shahid, Camille Dumat, Nabeel Khan Niazi, Sana Khalid, Natasha Natasha · VertigO · Global

Arsenic concentrations exceeding the World Health Organization's recommended limit (10 μg/L) have been frequently found in groundwater in several countries globally, exposing millions to arsenic. This study synthesizes recent interdisciplinary knowledge on arsenic, particularly for urban gardeners and farmers who may face contamination in well water or produced vegetables. Geogenic arsenic poses a major health threat in many countries, especially in Asia, and advice is proposed to avoid and reduce human exposure to arsenic in urban agriculture contexts.

Sara J. Taetzsch, Andrea S. Bertke, Karen Gruszynski · Zoonoses and Public Health · United States (Richmond)

This study investigated the potential overlap between feral cat territories and human-frequented areas in the Richmond metropolitan area, Central Virginia, using GIS. From July to November 2016, 275 feral cats were trapped for TNR clinics. Findings showed that 8.0% of feral cats had the potential to range onto public elementary or preschool property, and 81.5% of those trapped in Richmond City could roam into public parks and community gardens, indicating a risk of zoonotic disease transmission.

M. L. Dotaniya, V. D. Meena, S. Rajendiran, M. Vassanda Coumar, Asha Sahu, J. K. Saha, S. Kundu, Hiranmoy Das, A. K. Patra · Journal of the Indian Society of Soil Science · India (Bhopal)

A case study in peri-urban agricultural lands near Patranala, Bhopal, India, investigated the impact of over 50 years of untreated sewage water irrigation on soil properties. Findings showed higher concentrations of heavy metals in surface soils of sewage-irrigated fields, posing a major concern. Conversely, soil microbial population, enzymatic activities, and organic carbon content were also higher, indicating enhanced carbon sequestration.

Simon Kojo Appiah, Eric Nimako Aidoo, Derrick Asamoah Owusu, M. W. Nuonabuor · Zenodo (CERN European Organization for Nuclear Research) · Ghana (Kumasi)

This paper assesses the spatial distribution of heavy metals and potential ingestion risks in Kumasi, Ghana, using geostatistical techniques on topsoil samples. Results from univariate and multivariate semivariogram models showed strong spatial dependence with autocorrelations ranging from 100 to 300 meters. The produced risk maps indicate strong spatial heterogeneity for most soil heavy metals, with extremely high contamination risk found near commercial areas.

Jane Entwistle, Patrick M. Amaibi, John R. Dean, Michael E. Deary, Daniel Medock, Jackie Morton, Ilia Rodushkin, Lindsay Bramwell · Environment International · United Kingdom

This study assessed gardeners' lead exposure in urban agriculture sites (UAS) to improve the derivation of soil assessment criteria. Researchers sampled nearly 280 paired soil and crop samples across 31 UAS gardens in the United Kingdom and measured blood lead levels (BLL) of 43 gardeners and 29 non-gardening neighbors. While 98% of sampled soils had lead concentrations above the current UK UAS soil guideline (80 mg/kg), all participants' BLL were below 0.1 mg/kg despite high soil lead. The study indicated that soil-to-plant concentration factors (SPCFs) used for UAS significantly over-predicted lead uptake.

Mayrina Firdayati, Peni Astrini Notodarmojo, Barti Setiani Muntalif, Didit Trihartomo, Inat Shani Fathuna, Kiki Somantri · INDONESIAN JOURNAL OF URBAN AND ENVIRONMENTAL TECHNOLOGY · Indonesia

Against a background of high helminth-infection prevalence in Indonesia — which led the government to issue a 2017 ministerial regulation on preventing soil-transmitted helminths (STH) — this study investigated the potential presence of helminth eggs capable of causing STH infection in two urban agricultural areas in the northern and southern parts of Bandung City. Samples of inlet and plantation-area water, soil, and harvested water spinach from both areas were analyzed for helminth eggs using a modified Bailinger method, and egg counts of 1–119 eggs/L were found across the water, soil, and vegetable samples. The results confirmed that irrigation water in both areas was contaminated with feces, with average fecal coliform counts exceeding the allowable value for irrigation water under Indonesia's Grade 4 water-quality criteria; variation in egg counts was attributed to environmental conditions such as temperature, humidity, and soil type. Helminth-egg levels in the irrigation water and land samples exceeded the values recommended by the WHO's 2006 guidelines for safe use of wastewater in agriculture, which the study links to an increased risk of helminth infection among consumers, agricultural workers, and residents near the farmland.

Tiantian Xiong, Camille Dumat, V. Dappe, Hervé Vezin, Eva Schreck, Muhammad Shahid, Antoine Pierart, S. Sobanska · Environmental Science & Technology · Global

This study assessed the phytotoxicity of copper oxide nanoparticles (CuO-NPs) in lettuce and cabbage, exposing them via leaves for up to 15 days to various CuO-NP concentrations. High foliar Cu uptake occurred, leading to decreased plant weight, net photosynthesis, water content, and necrotic Cu-rich areas. The findings highlighted a potential health risk associated with consuming vegetables contaminated with CuO-NPs.

Blaise Pascal Bougnom, Laura J. V. Piddock · Environmental Science & Technology · Global

This global perspective highlights the significant role of wastewater in urban agriculture as a factor in the dissemination of antibiotic resistance. Approximately 50-90% of antibiotics are excreted and end up in water ecosystems, particularly in low and middle-income countries with high antibiotic consumption. The aquatic environment acts as a reservoir and channel for the spread of clinically relevant antibiotic resistance traits.

Milan Geršl · · Czech Republic (Brno)

A study in Brno, Czech Republic, assessed toxic metal levels and soil attributes (pH, ORP, conductivity) in specific allotment garden areas using XRF analysis. Four out of eight metals (Cd, Cu, V, and Zn) exceeded legal norms, with cadmium (Cd) being the most hazardous at 12.69 mg/kg against a legal norm of 0.5 mg/kg. Despite high levels, the mobility of these metals was expected to be low given the detected soil attributes.

Muhammad Asif Khan Rai Muhammad Amir · International Journal of Biosciences (IJB) · Pakistan (Faisalabad)

To investigate heavy metal residue levels in cauliflower grown in the peri-urban area of Faisalabad district, Pakistan, 30 cauliflower samples were collected from 10 selected farmers. Analysis revealed variable heavy metal residue levels (nickel, lead, zinc, copper, arsenic, and mercury) in the samples, indicating that the cauliflower was contaminated with multiple heavy metals. This contamination is attributed to the use of untreated sewage water for cultivation, which is the single largest contributor to heavy metal accumulation in cauliflower.

Dan Luo, Haifeng Zheng, Ye Chen, Philippe Deleporte, Tianpeng Xie, Siobhán Staunton, G. Wang · Soil Use and Management · China (Fujian Province)

A large-scale survey across 515 sites and 24 crop species in Fujian Province, SE China, assessed nickel (Ni) accumulation in food crops and associated dietary health risks. Crop Ni content was influenced by both soil Ni (DTPA-extractible) and plant species, though PCA did not show strong correlations between soil-to-crop transfer factors and soil properties. The study concluded that dietary intake of foods with mean Ni content could lead to health risks, particularly for children, and that sandy soils rich in organic matter with high Ni content are unsuitable for growing rice and legumes.

Maud Chalmandrier, Marine Canavèse, Yves Petit‐Berghem, Élisabeth Rémy · HAL (Le Centre pour la Communication Scientifique Directe) · Global

This study, using case studies of public action and gardeners' relationships with urban soil, argues that the concept of "urban agriculture" smooths over inherent tensions to promote its development as an action category. This approach tends to minimize differences in meaning among actors regarding their cultivation practices and, critically, relegates the crucial question of urban soil quality and its suitability for food crops to a secondary concern.

Desta Woldetsadik, Pay Drechsel, Bernard Keraita, Fisseha Itanna, Berhanu Erko, Heluf Gebrekidan · International Journal of Food Contamination · Ethiopia (Addis Ababa)

An assessment in Addis Ababa, Ethiopia, analyzed 210 lettuce and 90 irrigation water samples for faecal coliform and helminth eggs. Faecal coliform levels ranged from 4.29-5.61 log10 MPN 100 ml−1 in water and 3.46-5.03 log10 MPN 100 g−1 on lettuce, exceeding WHO recommendations. Helminth eggs were detected in 80% of water and 61% of lettuce samples, also exceeding standards. While washing methods reduced contamination, levels remained in a potential risk range.

Marthe Ortolo · Infoscience (Ecole Polytechnique Fédérale de Lausanne) · Netherlands

This study outlines a plan to assess air pollution risks in urban agriculture in the Netherlands, focusing on heavy metal (Cd, Hg) and PAK accumulation in spinach in Amsterdam urban gardens. It includes a literature review, policy maker interviews, and practical measurements of airborne contamination. The study aims to model different uptake routes by plants, but actual findings on contamination levels are not presented in this abstract.

이윤숙 · · Global

Urban agriculture has gained emphasis due to its importance for leisure and recreation in modern society. However, public health may not be guaranteed due to continuous odors from animal compost. Biochar is an amendment that can reduce odors and enhance crop productivity, but this abstract is truncated and does not present specific research findings.

Abdul Rahman Conteh, Alusaine Edward Samura, E. L. S. Hinckley, Osman Nabay, Mohamed S. Kamara · Journal of Agricultural Science and Practice · Sierra Leone (Freetown)

This study was conducted to identify the risks of heavy metal contamination in urban and peri-urban cropping systems in Sierra Leone. Soil and plant samples were collected from 72 sites in Freetown and Bo and analyzed for Zn, Cu, Cr, Ni, Pb, and Cd. Heavy metals were detected across all sites, and some mild risk of cadmium toxicity was observed in densely populated areas of Freetown, though this was not reflected in plant uptake of cadmium.

Seyedardalan Ashrafzadeh, Niklas J. Lehto, Gareth Oddy, Ron G. McLaren, Ling‐Fen Kang, Nicholas Dickinson, Johannes Welsch, Brett Robinson · Applied Geochemistry · New Zealand (Christchurch)

A study in Christchurch, New Zealand, measured heavy metal (HM) concentrations in suburban garden soils and soils at risk of HM contamination due to former land uses or nearby activities. HM concentrations in suburban garden soils were higher than normal background levels, with 46% of urban garden samples exceeding the residential land use national standard for lead (210 mg kg−1), and the most contaminated soil reaching 2615 mg kg−1. Arsenic and zinc also exceeded national standards in 20% of soils. These findings suggest that soil HM concentrations should be key criteria when determining future land use for former residential areas demolished due to the 2010 and 2011 earthquakes, and that redeveloping these areas as parklands or forests would result in less human HM exposure than agriculture or community gardens where food is produced and bare soil is exposed.

Dorothy Menefee, Ganga M. Hettiarachchi · · United States

Soil contamination with potentially toxic trace elements and anthropogenic organic pollutants is a widespread problem in urban areas worldwide. While urban agriculture increases food security, potential risks exist without knowledge of urban soil contamination. Lead (Pb) contamination is a widespread and common urban soil issue associated with human health risks, with almost half of US EPA Superfund sites having Pb contamination. Cadmium (Cd) is also a widespread urban soil pollutant, largely from industrial activities like plastic manufacturing, battery disposal, and metal ore processing. The bioavailability of soil Pb to humans is unusually low and generally tied to Pb speciation.

Zane Vincēviča–Gaile, Dāvis Varakājs · · Latvia

This study aimed to determine the concentration of potentially toxic elements (Cd, Cr, Cu, Fe, Ni, Pb, Zn) in berries grown in allotment gardens in Rīga city, Latvia. Samples of raspberries, strawberries, red currants, black currants, gooseberries, and cherries were analyzed using atomic absorption spectroscopy. The results showed significant variability of element concentration among the berry species, with mean concentrations for Ni at 0.54 mg/kg, Pb at 0.20 mg/kg, Cr at 0.10 mg/kg, and Cd at 0.03 mg/kg.

Bethany B. Cutts, Jonathan London, Shaina Meiners, Kirsten Schwarz, Mary L. Cadenasso · Local Environment · Global

This paper applies a dynamic spatial politics framework to interpret a 30-year conflict over an urban garden in Sacramento, California. It examines how urban gardens, often idealized, are also sites of conflict due to competing visions of "soil" versus "dirt." The study highlights that contaminants like lead in the soil contribute to this instability, reframing fertile soil as dangerous dirt, and influencing the garden's transformation from a countercultural space to a gentrified amenity.

Eileen Bogweh Nchanji, Imogen Bellwood‐Howard, Nikolaus Schareika, Takemore Chagomoka, Johannes Schlesinger, D. Rodríguez Torres Axel, Glaser Rüdiger · International Journal of Agricultural Sustainability · Ghana (Tamale)

An ethnographic study in Tamale, Northern Ghana, assessed the sustainability of urban vegetable production between 2008 and 2014. While urbanization increased cultivation of profitable vegetables like cabbage, the practice involved irrigation with grey and wastewater and high pesticide use, posing health and environmental hazards. Industrial growth reduced open space urban agriculture by 8.7%, leading farmers to use interstitial spaces and peri-urban fringes, indicating a dynamic but not yet sustainable production system.

Sydney Giacalone · Journal for Undergraduate Ethnography · United States (Boston)

This ethnographic study, conducted in Boston and Somerville in the summer of 2016, investigated how urban chicken keeping might transform keepers’ thinking about food systems and animal relationships. The research revealed the unexpected discovery of lead contamination in urban chicken flocks in the Boston area, which unsettled the imagined simplicity of urban agriculture and exposed a "metabolic rift." This finding prompted keepers to engage more deeply with the history of the soil and opened new ways of thinking about collective metabolism, multispecies living, and food politics.

Ojuolape F. Akande, S. A. Ajayi · International Journal of Environment Agriculture and Biotechnology · Nigeria

This study measured heavy metals (As, Cd, Cu, Pb, Zn) in soil and in amaranth (Amaranthus hybridus) and jute mallow (Corchorus olitorius) vegetables from selected peri-urban farms around Osun State, Nigeria, to assess human health risk. Soil concentrations fell within FAO/WHO (2002) and EU (2006) agricultural background ranges, but vegetable samples showed appreciable metal levels; arsenic was below detection in all samples, amaranth showed higher retention than jute mallow for all metals except copper, the transfer-factor order was Cd > Zn > Pb > Cu, amaranth contributed the highest estimated daily intake for Cd, Cu, Pb and Zn, the health risk index was high for Cd and Pb but low for Cu and Zn, and the hazard index results indicate that vegetables grown on the selected peri-urban farms are not safe for consumption.