Research & reports

Andrew Hursthouse, T. E. Leitão, Annette Voigt, Avigail Heller, Béatrice Bechet, Paulo Brito da Luz · HAL (Le Centre pour la Communication Scientifique Directe) · Europe

This chapter overviews factors influencing the chemical, physical, and biological status of soils, water, and the biosphere in urban allotment gardens. It highlights that urban garden soils, water, and biosphere are affected by pollution due to their location in city centers or suburbs, with traffic infrastructure and industrial zones widely identified as impacting soil and water quality. Concerns over long-term risks from pollutant transfer (mainly metals) from soil to plants in these uncontrolled environments have been widely publicized.

M.P Dr. Enny Zulaika · · Indonesia

A study using Azotobacter isolated from eco urban farming land at ITS, Indonesia, tested resistance and bioaccumulation of mercury (HgCl2) via selective media isolation, streak resistance testing and atomic absorption measurement, analyzed by ANOVA and LSD at the 5% level. Three isolates (A5, A6, A9) tolerated HgCl2 up to 20 mg/L, and at 5 mg/L exposure the highest bioaccumulation efficiency was recorded for A5 (89%) and A9 (87%).

Anjar Lulu Sakinah · · Indonesia

Mercury is a highly toxic and hazardous heavy metal, and bacteria able to live in mercury-contaminated habitats — mercury-resistant bacteria, including Azotobacter — are known to exist. This study aimed to obtain superior Azotobacter isolates resistant to mercuric chloride (HgCl2) from land at the ITS (Institut Teknologi Sepuluh Nopember) Eco Urban Farming site — land where mercury contamination was present — and to determine mercury reductase enzyme activity as a bioreductant converting Hg2+ to Hg0. Isolation used selective Azotobacter agar media, resistance was tested by a slant-agar streak method containing HgCl2, and mercury reductase activity was analyzed using the MRA method and spectrophotometry at 340 nm. Ten HgCl2-resistant Azotobacter isolates were obtained; isolates A5 and A9 tolerated 10 mg/L HgCl2 with optimal growth and relatively high mercury reductase activity, showing a reduction capacity of ≥3 mg/L and a reduction efficiency above 70% at an HgCl2 concentration of 5 mg/L.

Arti Bhatia, Shivdhar Singh, Amit Kumar · Water Environment Research · India (Delhi)

A study in Delhi, India, investigated heavy metal contamination (cadmium, lead, zinc, copper) in irrigation water, soil, and vegetables from four peri-urban and one wholesale site. Most samples from peri-urban areas exceeded safe limits for lead and cadmium. Vegetables from the wholesale market showed only higher lead concentrations. Among peri-urban vegetables, only okra exceeded the safe limit for cadmium, while several wholesale vegetables (potato, coriander, chilies, pea, carrot) exceeded the limit for lead regarding health risk.

Jingjing Zhang, Jingshuang Liu, Rui Yu, Qiang Liu, Yang Wang · Human and Ecological Risk Assessment An International Journal · China (Jilin City)

This study analyzed 50 surface soil samples from urban vegetable fields in Jilin City, China, for thirteen organochlorine pesticides (OCPs). Based on soil quality standards, DDTs and chlordanes were categorized as light pollution, while HCHs showed no pollution for most samples. The study concluded that despite the presence of various OCPs residues, the soils are still safe and suitable for agricultural production.

Díaz Rizo, Óscar, Olivares Rieumont, Susana, D'Alessandro Rodríguez, Katia, López Pino, Neivy, Arado López, Juana Orquídea, Gelen Rudnikas, Alina, Díaz Arado, Óscar, Lima Cazorla, Lázaro, García Céspedes, Damaris, González Hernández, Patricia, Arencibia Carballo, Gustavo, Padilla Cabal, Fátima, Echevarría Castillo, Frank, Hernández Merlo, M., Casanova Díaz, A., Corrales Martínez, Y., Reyes, H., Viguri Fuente, Javier Rufino, Ródenas Palomino, Carmen, Santana, J. L. · UCrea (University of Cantabria) · Cuba

This 2015 study in Cuba used X-ray Fluorescence and Low Background Gamma Spectrometry to analyze heavy metal and radioactive element concentrations in marine/river sediments and urban soils. It found heavy metal contamination in coastal sediments of Guacanayabo Gulf and possible selenium contamination in the Sagua River estuary. The study also reported heavy metal concentrations in urban soils of Havana, Moa, Las Tunas, and Cienfuegos, including contamination levels in urban agricultural farms.

Jason Murillo, Environmental Health BCIT School of Health Sciences, Bobby Sidhu · BCIT Environmental Public Health Journal · Canada (Vancouver)

An online survey of 101 community gardeners from 23 community gardens in Vancouver, Canada, investigated perceptions of soil health and contamination. The study found no association between soil testing and garden location, nor between garden location and gardeners' confidence in soil safety. Despite potential health concerns from contaminated soil, community gardeners refrained from soil testing and remained confident in their soil's safety, indicating a gap in safety standards.

Gauthier Dobigny, Madougou Garba, Caroline Tatard, Anne Loiseau, Maxime Galan, Ibrahima Kadaouré, Jean‐Pierre Rossi, Mathieu Picardeau, Eric Bertherat · PLoS neglected tropical diseases · Niger

An extensive survey of urban rodents in Niamey, Niger, investigated the presence and distribution of rodent-borne pathogenic Leptospira species. Leptospires were not detected in the core city, but L. kirschneri was found in Arvicanthis niloticus and Cricetomys gambianus, rodent species restricted to irrigated cultures within the city. This study indicates the importance of market gardening in the maintenance and circulation of leptospirosis within Sahelian cities.

M. G. Dahiru, Onaiwu Idahosa Enabulele · · Nigeria (Kano)

Microbiological and physicochemical parameters of urban wastewater from the Jakara Canal in Kano were analyzed to assess its potential for irrigation. Mean fecal coliform counts ranged from 64.43 ± 63.20 MPN 100/ml to 216.85 ± 350.16 MPN 100/ml, increasing along the canal. All physicochemical parameters were within FEPA and WHO/FAO acceptable limits, but conductivity needed monitoring to avoid salinity.

Isabela Thomas Mkude · Journal of Water Resources and Ocean Science · Tanzania (Dar es Salaam)

This study assessed heavy metal concentrations in 12 groundwater samples from Keko and Kigogo areas in Dar es Salaam, Tanzania, during dry and rainy seasons. While copper and zinc concentrations were low, lead concentrations were detected beyond WHO permissible levels (0.01-0.35mg/l). This high lead presence may be attributed to urban agriculture activities, onsite facilities, and industrial waste discharge around the Msimbazi river.

Zhongqi Cheng, Anna Paltseva, Ireyena Li, Tatiana Morin, Hermine Huot, Sara Perl Egendorf, Zulema Su, Roxanne Yolanda, Kishan Singh, Leda Lee, Michael Grinshtein, Ying Liu, Kayo Green, Win Wai, Bushra Wazed, Richard K. Shaw · Soil Science · United States (New York City)

This study analyzed trace metal concentrations (Cr, Co, Ni, Cu, Zn, As, Cd, Pb) in 1,652 soil samples from 904 gardens in New York City. It found that many soils exceeded New York State Department of Environmental Conservation's Soil Cleanup Objective (SCO) limits for Pb, Cr, As, and Cd. Specifically, about 21% of community garden samples and 71% of home garden samples exceeded SCO limits for Pb and As, and less than 3% of all samples met criteria for unrestricted use.

Christine Aubry, Jeanne Pourias, Anne Cécile Daniel · HAL (Le Centre pour la Communication Scientifique Directe) · Global

Urban agriculture is gaining popularity, often for its contribution to urban greening, re-establishing connections between urban dwellers and agricultural and food production, and among urban dwellers themselves. However, urban agriculture also involves significant health issues, which advocate for urban planning that promotes its maintenance or establishment under healthy environmental conditions.

Emmanuel Yennumi Wandaat, Joseph Xorse Kugbe · Asian Journal of Agriculture and Food Sciences · Ghana

A study on vegetable production in Ghana's Tano South District surveyed 132 urban farmers and 5 stakeholders. Farmers relied solely on chemical pesticides for pest control and lacked in-depth knowledge of Integrated Pest Management (IPM). Inappropriate handling and non-use of protective clothing led farmers to report health issues like dizziness, skin irritation, and nausea, while indiscriminate spraying resulted in pesticide residues posing serious health risks to consumers and the environment.

Piotr Godyń, Maria Zielińska, Agnieszka Dołhańczuk-Śródka, Zbigniew Ziembik · Geology Geophysics & Environment · Poland

Soil samples were collected from 19 sites around the Opole industrial zone in Poland to determine the influence of the local metallurgical industry on soil contamination with metals, using Pb-210 as a contamination tracer. Results indicated that the metallurgical industry is not a source of environmental pollution in the immediate vicinity. Excessive lead concentrations ranged from 1 Bq/kg d.m. to 100 Bq/kg d.m. but were not strongly correlated with distances from the presumed source of contamination.

Vide Adedayo · Journal of Research in National Development · Nigeria (Lagos)

This study investigated poultry waste management in urban vegetable farms in Metropolitan Lagos from an ecosystem to human health perspective. Using a transdisciplinary approach, community participation, and socio-cultural, physiochemical, microbiological, and clinical information, the research revealed negative impacts and health problems associated with poultry waste management due to poor storage, composting, and packaging techniques. Consequently, adverse effects on users were identified.

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.

B.M. Mercado-Borrayo, Silke Cram Heydrich, Irma Rosas‐Pérez, Manuel Hernández Quiroz, Claudia Ponce De León Hill · International Journal of Phytoremediation · Mexico

In a natural wetland in the Mexico City Metropolitan Area — a major supplier of crops and flowers whose canals hold high concentrations of organochlorine (OC) and organophosphorus (OP) pesticides — bioaccumulation of these pesticides was studied in water hyacinth (Eichhornia crassipes), a plant considered a plague but suggested in the literature to have phytoremediation potential. In vivo bioaccumulation differences for OC pesticides were largely explained by their log Kow, while all OP pesticides showed bioaccumulation regardless of log Kow, and the higher bioaccumulation factors of some accumulated OC pesticides could not be explained by log Kow alone, suggesting passive transport into the plant. Translocation ratios showed water hyacinth to be an accumulating plant with phytoremediation potential for all the organophosphorus pesticides studied and some organochlorine pesticides, and an equation for free water surface wetlands with floating macrophytes showed pesticide removal by the wetland with room for improvement through better management.

Lydia G. Marquez‐Bravo, Dean B. Briggs, Hannah A. Shayler, Murray B. McBride, Donna Lopp, Edie B. Stone, Gretchen Ferenz, Kenneth G. Bogdan, R. G. Mitchell, Henry M. Spliethoff · Environmental Toxicology and Chemistry · United States (New York City)

A study analyzed 69 soil samples from 20 community gardens in New York City for 23 polycyclic aromatic hydrocarbons (PAHs) and black carbon, sampling both non-growing areas and vegetable-growing beds, including beds with and without visible PAH sources, at each garden. The sum of the US EPA's 16 priority PAHs reached up to 150 mg/kg, with a median of 5.4 mg/kg and mean of 14.2 mg/kg, similar to levels previously reported for urban areas in the northeastern United States. Isomer ratios indicated petroleum, coal and wood combustion as the main sources, and PAH concentrations were significantly and positively associated with black carbon and modeled air PAH concentrations, suggesting a link between historical atmospheric deposition and current soil PAH levels. Median PAH concentration in non-bed areas (7.4 mg/kg) was higher than in beds from the same gardens (4.0 mg/kg) and significantly higher than in beds without visible PAH sources (3.5 mg/kg); beds in gardens with records of soil amendments had 58% lower median PAH concentration than beds in gardens without such records, suggesting that gardening practices in beds without visible sources contribute to reducing soil PAH concentrations.

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.

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.

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).

Prem José Vazhacharickal, Sumita Gupta Gangopadhyay · Kobra (Universitätsbibliothek Kassel) · India

This paper examines urban and peri-urban agriculture (UPA) in India, focusing on wastewater irrigation and its associated human health risks. The study identifies potential health hazards for farmers, laborers, and consumers, including microbial pathogens and helminth (intestinal parasites). While UPA is presented as an option to address urban food demand, the paper emphasizes that "good practice UPA" requires integrated approaches and suitable risk reduction mechanisms to improve safety.

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.