Research & reports

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

This study investigated heavy metal pollution levels by collecting 50 soil samples from urban vegetable fields in Jilin City, China. Mean contents of Pb, Cr, Cu, Ni, Zn, and Cd were higher than their corresponding natural background values. However, the distribution of comprehensive pollution index values indicated that concentrations of these heavy metals in most agricultural fields did not exceed baseline values affecting agricultural production safety and human health according to China's soil environmental quality standard, concluding insignificant contamination by these metals in Jilin City.

UM Dawaki, A. U. Dikko, SS Noma, U. Aliyu · Nigerian Journal of Basic and Applied Sciences · Nigeria

A study investigated the total, exchangeable, and soluble concentrations of heavy metals (Cu, Cr, Ni, Zn, Pb, Cd) in urban agricultural soils along three rivers (Challawa, Jakara, and Watari) in Kano, Nigeria. Cadmium concentrations at Jakara and Challawa exceeded maximum allowable concentrations in soils. Heavy metal concentrations were found to be significantly higher in areas irrigated with industrial and domestic sewage (Challawa and Jakara) compared to the control site (Watari).

A. N. Mutune, M. A. Makobe, Mary Abukutsa‐Onyango · African Journal of Environmental Science and Technology · Kenya (Nairobi)

This study analyzed heavy metal content in 10 common African leafy vegetables and their rhizosphere soils from 25 sites along Nairobi Rivers, Kenya. While soil metal concentrations were generally within WHO/FAO permissible levels, except for some cadmium instances, all metals except copper in vegetables exceeded recommended limits at a few sites. This indicates potential heavy metal absorption from industrial and domestic effluent.

Abdirahman Osman Warsame, Fadumo Abdi Mohamud, Ahmed Hassan Ali · Zenodo (CERN European Organization for Nuclear Research) · Democratic Republic of the Congo (Kinshasa)

This scoping review synthesized evidence on the association between heavy metal contamination in vegetables sold in Kinshasa's urban markets, Democratic Republic of the Congo, and human biomarkers of consumer exposure. Available evidence consistently showed that vegetables, particularly leafy greens, from Kinshasa markets contained elevated levels of lead and cadmium, often exceeding international safety limits. However, studies directly linking vegetable contamination with human biomarkers are notably scarce, suggesting a potential exposure pathway but not establishing definitive causation.

Ashley S. Harms, DeAnn Presley, Ganga M. Hettiarachchi, Chammi P. Attanayake, Sabine Martin, Steven J. Thien · Natural sciences education · United States (Kansas City)

This case study examines the decision faced by Mr. John Holloway in Harmony Park, Kansas City, MO, regarding establishing a community garden on a vacant brownfield site in 2009. Concerns arose about soil contaminants on the site, leading to a dilemma about the potential harm versus benefits of gardening in a food desert. The case requires students to evaluate environmental, agronomic, human health, social, and economic issues related to urban soil contamination.

Suarau Odutola Oshunsanya, Tolafe Olayinka Adeniran · Agricultura tropica et subtropica · Nigeria (Ibadan)

A field experiment in Ibadan investigated the quality of irrigation water used for dry season vegetable cultivation along Ona-stream. Water samples from five isolated ponds and one locally dug well were analyzed for heavy metal status. Results showed high concentrations of Pb, Cr, and Co in soil from five farms (A-E) near the stream, and isolated pond water also contained Cr, Co, and Pb exceeding safe consumption thresholds. All vegetables irrigated with untreated isolated ponds contained Cd, Pb, and Ni concentrations above maximum permissible standards, posing potential risks to human health.

David R. Koenig · BIOS · United States (Sacramento)

This research project, conducted at the University of California, Davis, aims to understand how elevated soil lead levels may affect urban gardening activities in Sacramento, CA. The study investigates the distribution of soil lead levels in the city and how knowledge of this information impacts the local community. Elevated soil lead levels are identified as a potential barrier to urban gardening.

Kim Jin-Won, Yong-Man Yu, Na Won-Seok, Baljii Enkhjargar, Choi In-Wook, Youn Young-Nam, Young-Ha Lee Young-Ha · Horticultural Science and Technology · South Korea

In Seoul, South Korea, 260 samples of Chinese cabbage and lettuce were collected from four urban community gardens and six roof gardens between September and October 2012 and assessed quantitatively and qualitatively for microbiological and parasitological contamination. Mean total aerobic bacteria counts were 6.1±0.8 log CFU/g (range 5.4±0.6-7.1±0.8) and mean coliform counts were 4.0±0.7 log CFU/g (range 2.3±0.6-6.1±0.9), with coliforms detected in 59.6% of the 260 samples. There was no significant difference in contamination levels between cabbage and lettuce, but produce from community gardens showed higher levels than that from roof gardens (p>0.05). E. coli was isolated from 3.1% of vegetables at a level of 1.5±0.2 log CFU/g. Among foodborne pathogens, Staphylococcus aureus was detected in 1.5% of samples, while Salmonella spp., Listeria monocytogenes and E. coli O157:H7 were not detected in any sample. Unidentified parasite eggs were also found in two cabbage samples (0.8% of the total). The results indicate bacteriological contamination is present in produce grown through urban farming in Seoul, and the study calls for efforts to reduce biological contamination during cultivation.

Rebecca Kessler · Environmental Health Perspectives · Global

As interest in urban agriculture grows, researchers are working to manage the risks of contaminated urban soils. The focus is on maximizing the benefits of urban gardening while minimizing the potential hazards associated with soil contamination.

Robert Garey Stewart, Marcel Korth, Laurenz Langer, Shannon Rafferty, N Rebelo Da Silva · · Global

This paper is a protocol for a systematic review on the impacts of urban agriculture programs on food security and nutrition in low and middle-income countries. It notes potential disadvantages of urban agriculture, including contamination, spread of diseases, depletion of water supplies, soil erosion, and health risks from pesticides. The review aims to identify, appraise, and synthesize evidence on these impacts comprehensively and transparently, given that the existing evidence-base is not well understood.

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.

James R. Hollyer · PubMed Central · United States

This article discusses the potential risk of rat lungworm (Angiostrongylus cantonensis) in Hawai‘i's local food supply, which can cause eosinophilic meningitis if ingested by humans. While the statistical risk is extremely low compared to other foodborne agents, two individuals in Hawai‘i developed serious eosinophilic meningitis in late 2008 after consuming insufficiently washed local produce. The article highlights the challenge of informing the public about this rare but potentially serious disease, especially amidst efforts to promote local produce and school gardens.

Shazia Iram, Ayesha Zaman, Zaiba Iqbal, Rabia Shabbir · Polish Journal of Environmental Studies · Global

This study screened soil samples from peri-urban agricultural areas to investigate heavy metal contamination and identify heavy metal-tolerant fungi. Results showed that the majority of isolated fungi were resistant to lead (Pb) and chromium (Cr). Among the strains, Aspergillus niger was the most tolerant to Pb with an MIC of 600 mg/l, and Aspergillus flavus was the most tolerant to Cr with an MIC of 400 mg/l.

Marcelo Ortega Romero, Juan Mingot Marcilla, María Jesús García Martínez, Eduardo de Miguel, Miguel Izquierdo‐Díaz, Amaya Gómez · · Spain (Madrid)

This study evaluated the potential health risk from trace elements in urban garden soils in Madrid, Spain. Thirty-six composite soil samples were collected from the top 20 cm of six urban gardens, and concentrations of cobalt, chromium, copper, nickel, lead, and zinc were determined. The findings indicated that urban soils are significantly enriched in trace elements relative to background levels, suggesting a potential health risk.

Mansur Usman Dawaki, Abubakar U. Dikko, S. S. Noma, Umar Aliyu · Food and Energy Security · Nigeria

This study evaluated pollution risks to food security from urban agriculture in Kano, Nigeria, by sampling soil, water, and lettuce from two wastewater-irrigated sites (Challawa, Jakara) and a control site (Watari). Results showed all sites were contaminated with Cu, and the domestic wastewater site was slightly polluted with Pb and excessively polluted with Cd and Cr. Metal levels in irrigation waters exceeded recommended thresholds, and plants at the domestic wastewater site accumulated metal concentrations (Pb=26.21 mg/kg, Cd=1.03 mg/kg, Cr=28.63 mg/kg, Cu=2.66 mg/kg) that exceeded allowable limits in vegetables, indicating a human ingestion risk.

Mucig Charlotte · · France

A survey on rainwater harvesting in community gardens in France indicates that while this practice has been ongoing for years, it is poorly documented and faces challenges in adapting to new French regulations. The findings highlight public health issues for both garden users and consumers of fruits and vegetables, as well as environmental and operational concerns.

Mekonnen Getahun, Yihenew G. Selassie · Journal of Agricultural Science · Ethiopia

A study investigated the extent of contamination of soil, water, and vegetables from wastewater used for irrigation in urban agriculture in Bahir Dar and Kombolcha, Ethiopia. Soil, water, and vegetable samples were collected and analyzed. While heavy metal concentrations in soil were within permissible levels, wastewater samples showed high nitrate and phosphate levels, and boron concentrations in Borkena River and Lake Tana exceeded permissible limits for irrigation. Wastewater drained to Lake Tana exhibited high turbidity and very high BOD, and lettuce and Swiss chard accumulated higher levels of iron, manganese, and zinc.

Vittori Antisari, Livia; Dipartimento Di Scienze E Tecnologie Agroambientali, University Of Bologna, Bologna, Serena Carbone, Ferronato, Chiara; Dipartimento Di Scienze E Tecnologie Agroambientali, University Of Bologna, Bologna, Simoni, Andrea; Dipartimento Di Scienze E Tecnologie Agroambientali, University Of Bologna, Bologna, Vianello, Gilmo; Dipartimento Di Scienze E Tecnologie Agroambientali, University Of Bologna, Bologna · Archivio istituzionale della ricerca (Alma Mater Studiorum Università di Bologna) · Italy (Bologna)

Concentrations of heavy metals (Ba, Cd, Co, Cr, Cu, Ni, Pb, V, Zn) were determined in topsoil, plants, and moss tissues in the suburban area of Bologna, Italy, due to an urban waste incinerator and other atmospheric emission sources. No correlation was found between metal content and the incinerator plant's distance. The pollution load index (PLI) for soil and moss indicated low environmental pollution, but the highest values in sites downwind of the incinerator and in a craft area indicated moderate pollution.

Kibassa, Kimaro, Shemdoe · Scientific Research and Essays · Tanzania (Dar es Salaam)

A study assessing heavy metal concentrations in soils from selected urban agriculture areas in Dar es Salaam, Tanzania, found that zinc, chromium, cadmium, lead, and copper levels in all six investigated sites were within the Tanzania Bureau of Standards permissible limits. The highest values for copper, zinc, and lead were observed in Tazara Mchichani, potentially indicating pollution from surrounding manufacturing industries. Flooding did not appear to influence the distribution of these heavy metals.

Prem José Vazhacharickal, Martina Předotová, D. Chandrasekharam, Sharit K. Bhowmik, Buerkert, Andreas · Journal of Agriculture and Rural Development in the Tropics and Subtropics (University of Kassel) · India (Mumbai)

A study surveyed 38 railway gardeners to characterize urban and peri-urban agricultural production along railway tracks in the Mumbai Metropolitan Region. Irrigation water contained nutrients but also heavy metals such as lead, cadmium, and mercury, and pathogens like Escherichia coli. Heavy metal levels exceeded critical thresholds in surface soils for chromium, nickel, and strontium, and in produce for lead, cadmium, and strontium.

K.G. Rosin, Ravinder Kaur, Sushma Singh, Prabhat Kumar Singh, Digvijay Dubey · Procedia Environmental Sciences · India

A study was conducted in peri-urban agricultural sites around Faridabad, Haryana, India, to assess groundwater contamination and the contribution of salt/trace metal-laden irrigation waters. Mean EC, Cl, and F concentrations in root zone leachates were found to be far beyond permissible limits, and some trace metals posed a threat to deep percolating waters. However, due to existing cropping patterns and deeper water table depths, the groundwaters were not yet vulnerable to these salts/trace metals, and the presence of salts in the groundwaters was primarily geogenic.

Laura Knapp, Jodi L. Sangster, Shannon L. Bartelt‐Hunt · International Journal for Service Learning in Engineering Humanitarian Engineering and Social Entrepreneurship · United States (Omaha NE)

This study investigated the influence of lead hyperaccumulating plants on lead uptake by vegetables in an urban community garden in Omaha, NE, a region with significant lead contamination. Tomatoes, carrots, and amaranth were grown alongside sunflowers and mustard greens (hyperaccumulators) in lead-contaminated soil. Data showed higher lead concentrations in the hyperaccumulators and suggested that their presence might have impacted the amount of lead available to surrounding vegetation. Previous work at the garden detected lead in produce, indicating a potential exposure pathway for humans.

Kyle Kessler, Seth Umbenhauer, Alison R. Noble · Journal of the Pennsylvania Academy of Science · United States (Harrisburg)

Eight soil samples were collected from an urban land plot in Harrisburg, PA, to determine concentrations of copper, nickel, zinc, and lead and assess suitability for an urban garden. While copper, nickel, and zinc concentrations were below EPA recommended limits, lead concentrations ranged from 26 ± 1 mg/kg to 402+ mg/kg, with some samples exceeding EPA standards for heavy metals in home and vegetable gardens. This indicates potential lead contamination in the soil.

Chris Zimmerman · Soil Horizons · United States

A narrative article profiling the work of soil scientist Samantha Langley-Turnbaugh of the University of Southern Maine, investigating lead contamination in urban soils in Portland, Maine. It traces the concern to the Great Fire of 1866, whose lead paint ash was spread across the city and used as landfill to extend the Portland peninsula, compounded by the city's historical ties to lead-producing industries. The article states that, across US cities generally, lead paint and leaded gasoline are the primary sources of soil lead contamination, and that this contamination is becoming a concern as urban gardening expands.

Ines Vlahović, Ksenija Karlović · Agronomski glasnik ·

A survey conducted from May to August 2011 examined the frequency of poisonous and allergenic plant species at nine educational institutions in the town of Samobor, Croatia — three kindergartens, four elementary schools, one high school and one library. The survey identified 15 poisonous plant species, represented by 182 specimens, and 17 allergenic plant species, represented by 129 specimens.