Research & reports

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.

W.-L. Rao, Z.-K. Zhang, Runzhong Li · Plant Disease · China (Kunming)

In June 2007, sweet cherry trees with mottling and mosaic symptoms were observed in a private garden near Kunming, Yunnan Province, China. Twenty-four samples from sweet cherry, sour cherry, flowering cherry, and peach trees in private and community gardens were tested for eight viruses by RT-PCR. Cherry virus A (CVA) was detected in two symptomatic sweet cherry trees, marking the first report of CVA in sweet cherry in China.

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.

Adedeji Adedeji, H Oludare, Ademiluyi · Journal of Geography and Regional Planning · Nigeria

This discussion of urban agriculture and urban land use planning in metropolitan Lagos, Nigeria, frames urban agriculture as a crisis response and survival strategy for the urban poor that contributes to food security, while stating that urban agriculture production systems can pose risks to public health and the environment through inappropriate or excessive use of agricultural inputs — including pesticides, nitrogen, and raw organic matter containing heavy metal residues. It recommends that urban land use planners promote multifunctional land use and greater community participation in managing urban open spaces.

Abha Singh, Salahuddin Mohd. · National Geographical Journal of India · India

In-depth field research around the Iglas sewage pumping station on the Aligarh-Mathura road in Aligarh, India, surveyed 41 farming households and some consumers across five peri-urban villages — Bhojpura, Hari Narayan ki Sarai, Hajipur Chohata, Kheri Khwaja Buddha and Daurala Nirpal — that had used urban wastewater for irrigation for many years. Farmers and vegetable sellers reported suffering from ailments including diarrhoeal disease, typhoid fever, hookworm, amoebiasis and skin infections, yet their primary concern was securing enough water to sustain crop productivity and income, while consumers were more focused on getting a fresh, steady supply of vegetables than on the health risk.

Andréa Andreis, Graziela Maria Schuh, Rejane Giacomelli Tavares · LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) · Brazil (Novo Hamburgo)

An evaluation of parasite contamination in playground soils at Horta Comunitária Joanna de Angelis in Novo Hamburgo, RS, Brazil, detected rhabditoid larvae in 33% of soil samples. An enteroparasitological survey (n=22) confirmed parasitism in 59.10% of samples. However, it was not possible to establish a correlation between the presence of parasitosis in children and in the soil.

Bernard Keraita, Pay Drechsel, Flemming Konradsen · Journal of Risk Research · Ghana

A study in Ghana used participatory research methods to summarize farmers' perceptions of health risks and risk reduction measures in urban vegetable farming irrigated with untreated wastewater. Farmers were aware of health risks from wastewater, perceiving occupational skin infections as the greatest risk, while consumer health risks were rated very low. Many international risk reduction measures were deemed unsuitable by farmers, who preferred simple, low-cost alternatives.

Tamara García–Armisen, Josué Prats, Yociel Marrero, Pierre Servais · Water Science & Technology · Cuba (Havana)

The Almendares River in Havana, Cuba, receives wastewater from over 200,000 inhabitants, resulting in very poor microbiological water quality downstream due to high faecal bacterial indicators (FBIs). This water is used for urban agriculture and recreation, despite not meeting microbiological standards. This study compared FBI removal in three wastewater treatment plants (WWTPs): a conventional facility, a constructed wetland (CW), and a solar aquatic system (SAS). Natural systems (CW and SAS) showed approximately two log units higher FBI removal efficiency than the conventional plant. The large conventional WWTP was found to have a negative impact on the river's microbiological quality.

Pay Drechsel, Olufunke Cofie, R. van Veenhuizen, Theophilus O. Larbi · Irrigation and Drainage · West Africa

Informal irrigation in urban and peri-urban agriculture (UPA) in West Africa offers benefits but is often hindered by water pollution, threatening public health. A multi-stakeholder process implemented since 2005 in six West African cities, including Accra, Ghana, aimed to integrate UPA into sustainable urban development. However, an internal lesson learned was that local partners may not prioritize every project, and capacity-building efforts might not provide expected incentives for commitment.

Evan Green · · United States (California)

A literature meta-analysis on lead contamination in urban farms was applied to Alemany Farm in San Francisco, California, where soil lead concentrations range from 60 to 720 ppm. It found that every food crop except tree fruits may pose a health risk if grown in Alemany Farm's soil. A phytoremediation plan using Indian mustard (Brassica juncea) to remove lead was found to exceed the farm's available budget, and its timescale made it impractical. The study concludes that phytoremediation is generally not feasible for small-scale urban farms and that other measures are needed to reduce lead exposure for urban farmers.

Barbara Matthys, Andres B. Tschannen, Norbert T. Tian‐Bi, Hermann Comoé, Salia Diabaté, Mahamadou Traoré, Penelope Vounatsou, Giovanna Raso, Laura Gosoniu, Marcel Tanner, Guéladio Cissé, Eliézer K. N’Goran, Jürg Utzinger · Tropical Medicine & International Health · Côte d'Ivoire

A cross-sectional survey was conducted in urban farming communities in Man, western Côte d'Ivoire, involving 113 farming households (586 individuals) and 21 non-farming households (130 individuals). The prevalences of S. mansoni and hookworm in farming households were 51.4% and 24.7%, respectively. Risk factors for S. mansoni included close proximity to the Kô River, water contact with irrigation wells and ponds, and low education attainment, while risk factors for hookworm included living in smallholder irrigated rice plots or large rice perimeters, using domestic well water, and low socioeconomic status.

Astrid Mendez, Paulo Cseri Ricardo, P Jeny Pérez, Callejas Hernández, Osvaldo Campos · DOAJ (DOAJ: Directory of Open Access Journals) · Cuba

This introductory study in Arroyo Naranjo municipality, Cuba, examined the use of Luyanó effluent wastewater for irrigation in urban agriculture. The wastewater was classified as low contamination based on BOD5 and COD values and posed no toxic contamination risk to soil or environment. However, it should not be used without prior treatment for direct consumption crops due to its microbial load. Experimental plots with carrot, radish, and marigold showed high agricultural yields, and radish harvests had no bacterial contamination.

Samantha Langley-Turnbaugh, David E. Wilkinson, D. Rocque · Soil Survey Horizons · United States

This study characterized urban soils in a low-income neighborhood of Portland, Maine, that was heavily industrialized in the late 1800s, examining seven pedons for particle size, cation exchange capacity (CEC), base saturation, exchangeable bases, pH, and trace elements (Pb, Cr, Cu, Co, Cd, Ni, Zn, Hg, Ti, Zr). The soils contained numerous artifacts and showed a high degree of horizontal and vertical spatial variability; several trace elements were present at elevated levels, with lead (Pb) the dominant metal in surface horizons (600 mg/kg), and many metals correlated with each other and with iron and aluminum, and some with clay content and pH, though the study concludes that mapping soil units by specific trace element ranges would be difficult given the extreme variability observed.

Tanja Pless‐Mulloli, Vivienne S. Air, Catherine Vizard, Ian Singleton, D. L. Rimmer, Philip Hartley · Epidemiology · United Kingdom

A study in an urban, industrial allotment site in the UK's northeast assessed the potential for public health impact related to soil contamination by taking 86 soil samples and analyzing vegetables and eggs. All 18 initial soil samples exceeded UK guidelines for lead (median 869 mg/kg) and arsenic (median 40 mg/kg), and widespread contamination with PCDD/F was also found. Despite high soil contamination, the uptake of lead and arsenic into vegetables and eggs was low, and these were not deemed major exposure pathways.

F.P. Huibers, O. Moscoso, Álvaro Ocampo Durán, J.B. van Lier · CABI Publishing eBooks · Bolivia

A study examining wastewater use in urban and peri-urban agriculture in Cochabamba, Bolivia. Both vegetable and fodder crops are irrigated with polluted water — diluted or partly treated municipal and industrial sewage — containing high concentrations of pathogens, heavy metals, and salts. In the downstream La Mayca area, where farmers have an agreement with the municipal water and sewerage company, soil degradation has forced them to increasingly replace vegetable crops with more salt-tolerant fodder crops. In other areas around the city, cultivators deny using wastewater and point to nearby wells as their water source, but many of these wells are likely also polluted and do not yield enough water for the irrigated area they serve. Farmers report no specific health problems related to using polluted water, which contradicts reports from local health workers. Because surface water flow and rainfall are low while industrial pollution is high and wastewater treatment capacity is limited, most of the water available to farmers is of poor quality. Options identified for improvement include reducing industrial pollution, increasing treatment capacity, and adopting integrated water management that blends good-quality groundwater with wastewater — but strong traditional water rights, lack of urban planning, and weak institutions are cited as constraints on improving wastewater management in Cochabamba.

Tanja Pless‐Mulloli, Karen L. Foster, J Bush · Epidemiology · United Kingdom (Newcastle upon Tyne)

Investigations in Newcastle upon Tyne, UK, analyzed the extent and consequences of disposing 2000 tons of incinerator ash on over forty allotments. Soil, egg, and vegetable samples (75 soil, 21 egg, 65 vegetable) revealed contamination of footpaths with dioxin/furan (max 9000 ng/kg I-TEQ) and high levels of copper, lead, and zinc. Mean dioxin/furan levels in soil were 38 ng/kg I-TEQ and in eggs were 16.4 ng/kg I-TEQ, indicating significant contamination and potential exposure pathways for allotment gardeners and children.

B. Jankiewicz, B. Ptaszyński, Michael Wieczorek · Polish Journal of Environmental Studies · Poland (Lodz)

This study presents the results of lead determination in the soils of six allotment gardens located in various parts of Lodz. Lead was measured spectrophotometrically in the form of pink lead(II) dithizonate.

B. Jankiewicz, B. Ptaszyński, Michael Wieczorek · Polish Journal of Environmental Studies · Poland (Łódź)

This study determined cadmium in the soil of six allotment gardens in Łódź, located in areas with different traffic patterns (city center and suburbs). Cadmium was detected in the form of cadmium (II) dithizonate using the extraction-spectrophotometric method. This research indicates the presence of cadmium contamination in urban allotment garden soils.

James R. Preer, Ahmed N. Abdi, Harkewal S. Sekhon, George B. Murchison · Journal of Environmental Science and Health Part A Environmental Science and Engineering and Toxicology · Global

This study investigated cadmium (Cd) and zinc (Zn) concentrations in vegetables grown in community gardens on different urban soils. Vegetables from a low-pH urban soil without contamination history showed higher Cd and Zn levels than those from a reclaimed landfill with digested sewage sludge, and also higher than a low-metal, neutral-pH site. Liming on the low-pH site reduced Cd and Zn concentrations in beet, lettuce, radish, and Swiss chard leaves, reaching background levels after four years. The findings indicate that soil pH is more important than total soil Cd and Zn in determining vegetable metal availability.

M. Krelowska‐Kulas · Food / Nahrung · Poland (Kraków)

An investigation using atomic absorption spectroscopy in Kraków, Poland, found that vegetables from urban allotment gardens had average levels of lead, cadmium, copper, zinc, and iron several times higher than control samples from farms 100 km away. In some cases, maximum levels of certain elements approached the admissible limit. However, average levels of lead and cadmium in pigs and cattle showed no reason for objection.

Howard J. Atkinson, Naomi Gibson, Harry C. Evans · Plant Pathology · United Kingdom (Leeds)

A survey of 140 growers across 12 allotment sites around Leeds, UK, identified a wide range of crop pests, with brassicas, potatoes, and carrots being more frequently damaged. Soil samples from 33 plots at 10 established sites and 6 plots at 2 new sites revealed potentially damaging levels of pale potato cyst nematode in 21 and 1 plots, respectively. Widespread overwintering populations of carrot fly larvae and pupae were also found in soil samples from eight sites.