Research & reports

Nirosha Ruwani Amarasekara, Abdullah Ibn Mafiz, Xun Qian, James M. Tiedje, Weilong Hao, Yifan Zhang · Journal of Agriculture and Food Research · Global

Metagenomic analysis of total soil DNA from urban vegetable garden soils examined the co-occurrence of antibiotic resistance genes (ARGs) with resistance genes to other compounds, including heavy metals and biocides. Relative abundance was 2.00-2.90 x 10^-1 copies per 16S rRNA gene for ARGs and 4.22-6.00 x 10^-2 for metal resistance genes (MRGs), with the most abundant ARGs conferring multidrug, vancomycin, bacitracin, fosmidomycin, and macrolide-lincosamide-streptogramin (MLS) resistance, alongside MRGs for copper, arsenic, multiple metals, iron, and chromium, biocide resistance genes (BRGs) for multi-biocide, peroxide, and phenolic compounds, and multi-compound resistance genes (MCRGs) combining biocide-metal, drug-biocide-metal, and drug-biocide resistance. Multidrug resistance genes (including mexF, mexW), the MLS gene macB, and the MCRG ruvB showed the strongest correlations with other resistance genes, demonstrating extensive co-occurrence of ARGs, MRGs, BRGs, and MCRGs in urban agricultural environments and suggesting that soil contaminants have potential as co-selection agents for antibiotic resistance.

Yang Deng · Journal of Hazardous Materials Letters · Global

While rainwater harvesting (RWH) is considered a sustainable irrigation method for urban agriculture, contaminants in rainwater pose challenges to RWH practices due to potential threats to crop, soil, and human health. Based on literature data, principal pollutants such as particles, toxic metals like cadmium, copper, and zinc, synthetic organic chemicals like agrochemicals and polycyclic aromatic hydrocarbons, and waterborne pathogens were identified as likely exceeding irrigation quality criteria. This study identifies challenges, knowledge gaps, and research needs for RWH irrigation, offering a basis for technical strategies.

Isaac Asirifi, Korbinian Kaetzl, Steffen Werner, Courage Kosi Setsoafia Saba, Felix K. Abagale, Philip Amoah, Bernd Marschner · Journal of Environmental Quality · Ghana

A field experiment in northern Ghana assessed health risks from pathogen and heavy metal contamination in urban agriculture, evaluating rice husk biochar, N-P-K fertilizer, and their combinations with untreated wastewater or tap water irrigation. While heavy metals in irrigation water and soil were below FAO/WHO standards, wastewater irrigation caused significant E. coli, fecal coliform, and helminth egg contamination on red amaranth vegetables and in soil. Biochar application did not affect bacterial contamination.

Enrico Buscaroli, Ilaria Braschi, Chiara Cirillo, Agnès Fargue‐Lelièvre, Giuseppe Carlo Modarelli, Giuseppina Pennisi, Isabella Righini, Kathrin Specht, Francesco Orsini · Food Control · Global

This paper addresses the potential underestimation of food safety risks in urban agriculture (UA), which can lead to regulatory gaps, despite positive perceptions of UA. It reviews literature on UA food safety assessments, identifying indicators and developing a framework for evaluating food safety risks in UA initiatives. The framework uses business surveys and food analyses to calculate a food safety index for UA businesses and city regions.

Shwan Mohammed, P. K. Nyade, Mohamad Abdulhamid, I. O. A. Hodgson · Water Science · Ghana (Accra)

This study assessed urban water quality parameters of the Nima Creek in Southeastern Accra, Ghana, sampling water from six locations. The results showed high enrichment of nutrients (ammonia, nitrate, phosphate) and elevated levels of BOD, COD, and grease at sites receiving solid and liquid wastes. Physicochemical parameters like conductivity, TSS, and TDS also exhibited elevated values, indicating significant contamination that poses challenges for sustainable urban agriculture.

Nazir Muhammad Abdullahi, Ernest Chukwusoro IGWE, Munir Abba Dandago, Naima Umar · FUDMA Journal of Sciences · Global

This review discusses heavy metal contamination in food crops, identifying wastewater irrigation, agrochemical abuse, contaminated fields, atmospheric deposition, and unethical mining as primary sources. Agricultural soil in urban and peri-urban areas is heavily contaminated due to anthropogenic activities, with wastewater irrigation intensifying this contamination. Heavy metals are transferred to food crops during production and subsequently to humans upon consumption, posing a detrimental risk.

Camille Dumat · Aspects in Mining & Mineral Science · Global

This paper discusses the negative environmental and health impacts of mining, such as air and soil pollution, despite its socio-economic benefits. It highlights that urban agriculture, particularly in areas near former mining sites, faces challenges regarding soil quality and the production of unpolluted vegetables due to public concerns about contamination.

Ahmed Khadra · IGI Global eBooks · Global

This chapter examines the health effects of climate change, specifically focusing on the global issue of fecal peril caused by intestinal parasites. It suggests that water shortages, driven by climate change, increase pressure on water resources, leading to greater use of urban wastewater for irrigation in urban agriculture. Unsafe management and inappropriate wastewater use are likely to exacerbate the transmission of infectious diseases, including those caused by intestinal protozoa and helminths.

Francis Mwanza, Erick Komba, Dominic Kambarage · International Journal of Microbiology · Tanzania (Dar es Salaam)

This study in Dar es Salaam, Tanzania, investigated the occurrence, antimicrobial resistance, and genetic relatedness of E. coli isolates from 156 samples of manure, vegetables, and fish. Of these, 36 samples (23.1%) were positive for E. coli, yielding 48 isolates. A significant finding was that 25 (52.1%) of these isolates were resistant to at least one antimicrobial agent, and 12 (48.0%) showed multidrug resistance, indicating a potential microbial health risk to humans through contamination.

Anna Barra Caracciolo, Valentina Terenzi · Microorganisms · Global

A review of the rhizosphere as a microhabitat of intense chemical dialogue between plants and microorganisms covers synergistic interactions that can enhance plant function and productivity, including responses to stress conditions such as heavy metal (HM) contamination, alongside the risks such contamination poses. Where heavy metals are present in agricultural soils, there is a risk of metal uptake by edible plants leading to bioaccumulation in humans and animals with detrimental health consequences, and plant productivity itself can be negatively affected; many bacteria have defensive mechanisms for resisting heavy metals and can improve plant responses to HM stress, but achieving such beneficial rhizosphere interactions is described as hard to attain in agroecosystems managed with traditional practices that focus on maximizing crop yield.

Olga Romanova, Sarah Taylor Lovell · Urban Agriculture & Regional Food Systems · Global

This review assesses the capacity of woody species (trees and shrubs) used in urban food forests to accumulate polycyclic aromatic hydrocarbons (PAHs), heavy metals (HMs), and metalloids, given limited existing literature on food-safety risk in urban fruit- and nut-producing trees compared with annual crops. General trends identified were (a) lower risk of HM and PAH accumulation in woody species than in vegetables, and (b) less accumulation in the fruit of woody species than in other parts of the same species. However, these trends are not always consistent, and accumulation depends on factors such as the concentration of a given contaminant in the environment, contaminant type, and species or variety. The review states there is a critical need for more research on the safety of growing edible fruits and nuts on trees and shrubs in contaminated urban environments.

Tanmoy Roy Tusher, Md. Eusuf Sarker, Sumaya Nasrin, Tapos Kormoker, Ram Proshad, Md. Saiful Islam, Shamim Al Mamun, A. R. M. Tareq · Toxin Reviews · Bangladesh

This study investigated toxic metal and PAH contamination in rooftop soils and vegetables (red amaranth, spinach) in urban and peri-urban Bangladesh. Urban rooftop soil and vegetables were highly contaminated with toxic metals and PAHs compared to peri-urban samples. Lead (Pb) and cadmium (Cd) concentrations in urban vegetables exceeded safe limits. However, health risk indices indicated that the levels of toxic metals and PAHs in urban rooftop vegetables would not pose carcinogenic or non-carcinogenic health risks for adults and children, deeming them safe for consumption.

Fabien Ilunga Mpanga, Michel Shengo Lutandula⃰ · The Global Environmental Engineers · Democratic Republic of Congo (Lubumbashi)

A study conducted in the Kasungami district of Lubumbashi, Democratic Republic of Congo, investigated the link between the use of polluted waters in urban agriculture and heavy metal contamination in soil and cultivated vegetables (amaranths, broccolis). Physicochemical and mineral analyses of water, soil, and plant samples revealed that heavy metals, except cobalt, were present in the water used for urban agriculture at concentrations below quality standards, but the soil contained heavy metals at phytotoxic concentrations. Only broccolis were contaminated with lead, while amaranths had heavy metals below quality standards. These findings suggest that urban agriculture in large agglomerations of the DRC could endanger consumers' health.

Gábor Teke, Katalin Hubai, Dorina Diósi, Nóra Kováts · Bulletin of Environmental Contamination and Toxicology · Global

This laboratory study assessed the foliar uptake and accumulation of airborne polyaromatic hydrocarbons (PAHs) in lettuce (Lactuca sativa) using an aqueous extract of urban aerosol, following OECD Guideline 227. The study found significant accumulation of PAHs in lettuce, with naphthalene showing the highest bioconcentration factors (BCFs) and anthracene, pyrene, and fluoranthene showing the lowest bioaccumulation potential. The BCF of each PAH strongly correlated with its molecular weight.

Maëlle Tripon, Dorothée Boccanfuso, Marie-Ève Yergeau · Cahiers de recherche · Global

This literature review examines urban agriculture (UA) models, their implementation contexts, production needs, and impacts. It highlights that UA faces limitations, particularly restricted access to good quality (unpolluted) soil, water, and air, which can negatively impact productivity. UA can also have negative impacts on ecosystems and human health, such as pollution and diseases, depending on management methods.

Herman Parfait Awono-Ambene, Laurelle Djieukap Njieyap, Patrick Akono Ntonga, Josiane Etang, Christophe Antonio‐Nkondjio, Cyrille Ndo, Jacques Étamé, Flobert Njiokou, Serge Hubert Zébazé Togouet · Journal of Environmental Science and Public Health · Cameroon (Yaounde)

This study analyzed water and soil samples from three market garden sites in Yaounde, Cameroon, from October to December 2016, for physicochemical characteristics and parasite identification. The analysis of 82 samples revealed the presence of 3 protozoans (Entamoeba histolytica, Sarcocystis sp., and Giardia intestinalis) and 11 helminths in the soil. The presence of viable helminths suggests that harmful soil pathogens such as protozoans and helminths can spread through market gardening.

Милена Йорданова, Вера Петрова, Цветелина Николова, Елена Цветкова, Milena Yordanova, Vera Petrova, Tsvetelina Nikolova, Elena Tsvetkova · Bulgarian Portal for Open Science · Global

This article considered the potential risks of contamination in urban agricultural products. Urban agriculture, particularly in large cities, areas with heavy traffic, or near industrial zones, can lead to the accumulation of heavy metals in vegetable crops due to air pollution, traffic pollution, and other sources. Consuming these contaminated fresh vegetables is noted to potentially deteriorate human health.

Razzaq Ahmed, Shaukat Khan, Khalida Mahmood, Ahsanullah · Irrigation and Drainage · Pakistan (Karachi)

Agricultural activities in the Gadap Basin, Karachi, Pakistan, showed a declining trend over two decades from 1997 to 2016. Analysis of 13 irrigation water samples revealed that water quality had severely degraded, with sodium concentration substantially increasing, especially near sand and gravel excavation sites. While 100% of samples were suitable for irrigation in 1997, this dropped to almost 50% by 2016, and SAR also decreased, indicating irrigation water quality degradation. Satellite imagery further showed a 60% decline and degradation of agricultural land in the basin during the same period.

H. Tayal Neeraj · · Global

This chapter explores the potential of home gardening, as part of urban agriculture, to contribute to human health through improved nutrition. While home gardens can provide nutrient-dense foods, the potential health impact of soil contamination must be addressed, as urbanized soils tend to have elevated levels of heavy metals and other toxins.

Baptiste Grard, Nastaran Manouchehri, Christine Aubry, Nathalie Frascaria‐Lacoste, Claire Chenu · International Journal of Environmental Research and Public Health · Global

A five-year experimental trial quantified the food production potential, soil fertility, and potential contamination of Technosols created from urban wastes for rooftop edible production. The cropping system showed promising results for food production and maintained high fertility. However, a concern was identified regarding the trace metal content of certain edible crops, specifically zinc (Zn) and copper (Cu), although most trace metal levels were below existing norms.

Joycelyn K. Quansah, Cesar L. Escalante, Angela Parry‐Hanson Kunadu, Firibu Kwesi Saalia, Jinru Chen · Agriculture · Ghana (Accra)

A survey was conducted among 102 urban leafy green vegetable farmers from 12 farming areas in Accra, Ghana, to determine agricultural practices and their association with microbial safety of vegetables produced. It was observed that 70% of farmers used water from waste drains for irrigation, 99% used incompletely composted manure, 96% harvested with bare hands, and over 60% disagreed that polluted irrigation water can contaminate vegetables or make consumers sick. Vegetables cultivated by farmers with no formal education, less food safety knowledge, and those who disagreed about contaminated water causing illness were associated with higher fecal coliform and Enterococcus sp. counts.

Salvatore Engel‐Di Mauro · Journal of Environmental Quality · Global

This review examines atmospheric sources of trace element (TE) contamination in cultivated urban areas (CUAs), noting that these sources are understudied and poorly understood despite extensive research on TE contamination in CUAs. Existing research often assesses atmospheric deposition indirectly or lacks controls for other TE contaminants, and shows little engagement with atmospheric sciences methodological guidelines, which reduces confidence in current findings. The review suggests combining atmospheric science techniques with existing robust methodologies for TE contamination studies in CUAs.

Silke Cram, Pilar Fernández, Horacio Carranza, M.C. Gómez Hernández, Claudia Ponce de León, Ana M. Noguez Gálvez · Open Journal of Soil Science · Global

This study evaluated metal inputs, transfer, and translocation in lettuce (Lactuca sativa L.) grown in an urban plot during dry and rainy seasons in 2013, using treated wastewater and rainwater respectively. While soil characteristics and metal transfer/translocation factors varied temporally, leading to different metal concentrations in lettuce tissues, the results indicated that the metal concentration in lettuce tissues posed no harm to human health. However, site-specific studies are necessary for urban agriculture management.

Remigio Paradelo, Antía Villada, María Teresa Barral · International Journal of Environmental Research and Public Health · Global

A two-month pot experiment studied heavy metal transference from five metal-rich urban waste composts and a manure vermicompost to lettuce and Italian ryegrass under controlled conditions. Plant concentrations of Zn, Cu, and Cd increased with their concentrations in compost, while no such relation was observed for Pb. The study found that the ratio of element concentration in plant to compost was much higher for Zn, Cd, and Cu than for Pb, indicating lower bioavailability of Pb.

Ada Górna, Krzysztof Górny · Miscellanea Geographica · Cuba

An exploratory, classification-based study combining fieldwork with satellite and aerial imagery analysis characterized urban agriculture across the built-up areas of Havana, Cuba. It found urban gardens distributed unevenly across the city, concentrated in lower-density districts where land was intentionally left between buildings by modernist planners, with organopónico (organoponics) as the most common production technique — but found that the material commonly used to build the bordering walls of these plots is asbestos, posing a significant health threat to both producers and consumers.