Research & reports

Jihan Faouzi, Imane Bedoui, Sanae Rezouki, Tarik Moubchir, Aimad Allali, Noureddine Eloutassi, Amal Lahkimi · Ecological Engineering & Environmental Technology · Morocco (Fez)

This study in Fez, Morocco, compared bacteriological and parasitological contamination in urban, peri-urban, and rural irrigation waters, and their transfer to soil and crops (cardoon and eggplant). Investigated microorganisms included total and thermotolerant coliforms, helminth eggs, Salmonella, and cholera vibrio. Results revealed contamination exceeding national and international standards for both types of coliforms in treated wastewater (TWW), wastewater (WW), Oued Fez water, and upstream well water in both winter and summer. This fecal contamination was found in soils and crops irrigated by urban and peri-urban water. Helminth eggs and cholera vibrio were also present in these waters, soils, and crops, with Salmonella detected in TWW in summer. Only the plot irrigated with Oued Bitit water in the rural zone met standards across all three levels of irrigated water, soil, and plants, and in both periods.

Shiyu Cui, Wenbin Liu, Hexian Jin, Yi Qiao, Ying Wang, Dan Liu · Atmosphere · Global

This study investigated the effects of mixed cropping garden plants (Festuca arundinacea, Ageratum conyzoides, Trifolium repens) with Brassica parachinensis on Cr-contaminated soil remediation. While mixed cropping with Trifolium repens resulted in the highest B. parachinensis yield and Cr content below standard in edible parts, mixed cropping with Ageratum conyzoides aggravated Cr pollution in edible parts of B. parachinensis, making it unsuitable for planting.

Anna Paltseva, Zhongqi Cheng, Murray B. McBride, Maha Deeb, Sara Perl Egendorf, Peter M. Groffman · Frontiers in Ecology and Evolution · Global

This synthesis paper summarizes current scientific knowledge on lead (Pb) contamination in urban garden soils and provides clear recommendations for assessing actual health risks and limiting exposure. Urban garden soils often contain elevated levels of Pb, mainly from legacy sources, which is a main barrier for urban gardening. Amendments are noted as unreliable for treating contaminated soils to reduce risk, as they do not always make contaminants less harmful.

Nini Sané, Malick Mbengué, Amandine Laffite, Serge Stoll, John Poté, Philippe Le Coustumer · Water · Global

This study developed a wastewater treatment plant prototype coupled with Moringa oleifera seeds to reduce fecal indicator bacteria and antibiotic-resistant bacteria in domestic wastewater. The prototype alone reduced bacteria by 99.34%. The addition of Moringa oleifera seeds achieved high removal rates for E. coli (36.6–78.8%), fecal coliform (28.3–84.6%), Vibrio cholera (35.3–95.6%), and total flora (32.1–92.4%). For antibiotic-resistant bacteria, removal rates were up to 98% for E. coli and fecal coliform, 100% for Vibrio cholera, and 91.96% for total flora.

James D. Blount, Leah E. K. Lenoch, Faith A. Fitzpatrick · Journal of Great Lakes Research · United States

A study of Apple Creek, Wisconsin (119 km²), a Great Lakes tributary like many others subject to Total Maximum Daily Load (TMDL) targets requiring reductions of 51.2% in suspended sediment and 64.2% in total phosphorus. From August 2017 to October 2018, an integrated stream sediment budget and fingerprinting study quantified upland and stream-corridor sources of suspended sediment and sediment-bound phosphorus. Phosphorus concentrations varied among source groups and fluvial sediment types, with higher concentrations in suspended sediment and cropland soils. Eroding streambanks accounted for 100% of the TMDL model's (SWAT) suspended sediment load but only 20% of the total phosphorus load; fine-grained streambed sediment equated to roughly three years of modelled suspended sediment load but only one-third of the total phosphorus load. The two primary sources of fine-grained streambed sediment were streambanks and cropland, with the relative streambank contribution increasing downstream and with watershed area. The relative proportion of suspended sediment varied by season and streamflow, but weighted for representative streamflow, cropland and streambank erosion accounted for 54% and 23% of suspended sediment respectively. Urban land was a source in the upper watershed, but its signature was sequestered by a mid-watershed detention basin, and contributions from construction sites were higher in fall 2018, likely corresponding to increased activity following a wet spring.

Hae Jong Yang, Tae‐Woo Kang, Byungwoong Choi, Soon Hong Hwang, Dongseok Shin, Won-Pyo Park · Sustainability · South Korea

This study verified heavy-metal pollution levels in sediments of an urban-agricultural watershed in the Yeongsan River basin, South Korea, through evaluation of Sediment Quality Guidelines (SQGs), a pollution load index (PLI), and a potential ecological risk index (PERI), and analyzed statistical relationships between pollution levels, land use, and potential pollution sources. Pb, Zn, Cu, Cd, and Hg concentrations were highest at mid-upstream sites, while As, Cr, and Ni concentrations were similar across most sites. Sites showing potential toxicity to benthic organisms relative to SQGs were most frequently observed at mid-upstream, and PLI and PERI evaluations likewise confirmed high anthropogenic pollution and ecological risk there. Mid-upstream sites with high heavy-metal pollution correlated strongly with urban land use — the largest land-use category — indicating links to population density and industrial complexes; statistical analysis confirmed this relationship. The findings indicate that urban areas are highly likely to cause anthropogenic heavy-metal pollution of sediments via point and non-point sources such as domestic sewage and industrial wastewater.

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.

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.

Dong BaoCheng, Wei Li, Wenyong Xu · Antibiotics · China

A field experiment in peri-urban agricultural soil in China investigated the effects of partially substituting chemical fertilizer with organic fertilizers like pig manure and sewage sludge on soil quality and antibiotic residues. Organic substitution significantly increased residual antibiotic levels in agricultural soil, with antibiotic sequestration rising by 138.1~332.5%. This indicated that organic fertilizers can promote antibiotic persistence in soil by modifying soil quality, demonstrating a contamination risk.

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.

Cecilia Herbón, María Teresa Barral, Remigio Paradelo · Applied Sciences · Spain (Santiago de Compostela)

The concentrations of trace elements Cu, Pb, Zn, Ni, Cr, and As were investigated in 55 urban soils in Santiago de Compostela, northwestern Spain. While most soils showed higher trace element concentrations than regional backgrounds, they were not classified as contaminated according to Spanish regulations. However, geoaccumulation index values indicated low to moderate pollution levels in most soils, with Cu, Pb, and Zn highest in city center green areas, and Cr and Ni linked to parent material lithology.

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.

Moisés Savian, Mari Inês Caríssimi Boff, Pedro Boff · Cadernos de Agroecologia · Brazil

This study evaluated Brazilian scientific production from 2009 to 2018 on urban agriculture's contribution to food and nutritional security, analyzing 34 selected articles out of 612. It found that while agrobiodiversity is present in urban agriculture areas, pesticide use is a reality in some crop plots. The research suggests urban agriculture must be based on agroecology to avoid environmental contamination and produce healthy food.

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.

Hillary A. Craddock, Elisabeth Fost Maring, Stephanie Grutzmacher · African Journal of Food Agriculture Nutrition and Development · Ethiopia

A mixed-methods pilot survey of 21 teachers and parents in Debre Berhan, Ethiopia, investigated household agricultural practices to understand foodborne illness risks. The study found that half of respondents using manure applied uncomposted manure as fertilizer, and many kept multiple animal species. This suggests a high risk of pathogen exposure for children and adults through contact with uncomposted manure and animals.

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.

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.

Cosmos C. Alamanjo, Abimbola O. Adepoju, H. Martin, R.N. Baines · Zenodo (CERN European Organization for Nuclear Research) · Nigeria (Jos)

This mixed-methods study investigated farmers' perceptions, willingness, and capacity to use household sewage sludge as organic resources for peri-urban agriculture around Jos, Nigeria. Farmers were found to use a complex mix of fertilizers and were keen to utilize household sewage sludge for soil fertility, though constrained by accessibility. A critical finding was that household sewage sludge observed in the field is heterogeneous due to its proximity to urban refuse disposal, raising concerns for possible cross-contamination of pollutants and indicating a lack of extension guidance.

L.C. Obuseng · Botswana Journal of Agriculture and Applied Sciences · Botswana (Gaborone)

This review highlights the potential for heavy metal accumulation in soil and crops from urban and peri-urban agriculture (UPA) around Gaborone, Botswana, due to the intensive use of chemical fertilizers, pesticides, wastewater, sludges, and industrial effluents. A literature review showed that fertilizers contain heavy metals, and the use of treated or untreated sewage water by UPA farmers can lead to heavy metal accumulation in soil and crops, posing a danger to human health. Information on heavy metal accumulation in soils is limited in Botswana, despite high agrochemical use in UPA vegetable production.

Surendra K. Pradhan, Olufunke Cofie, Josiane Nikiema, Helvi Heinonen‐Tanski · Sustainability · Global

This research determined the fertilizer value of sawdust and fecal sludge (SDFS) pellets and compared their effect on lettuce cultivation with other fertilizers in a greenhouse and open field. SDFS pellets, with or without enrichments, resulted in higher saleable fresh weight lettuce yields than commercial compost, poultry manure, mineral fertilizer, or no fertilizer. Open field cultivation yielded more than greenhouse cultivation. While no helminth eggs were detected, some fecal coliforms were found in lettuces fertilized with almost all tested fertilizers, including NPK and the non-fertilized control.

Obinna Elijah Nworie, Junhao Qin, Chuxia Lin · Toxics · Global

This study investigated trace element uptake by wild herbaceous plants at a multiple trace element-contaminated site. It found significant variability in bioaccumulation and translocation factors among plant species, identifying some as hyperaccumulators for specific elements. The marked accumulation of trace elements in plant tissues suggests that the site may not be suitable for urban agricultural production.

Timo Falkenberg, Deepak Saxena · Indian Journal of Community Medicine · India (Ahmedabad)

A 12-month case-cohort study of 187 households in four communities of Ahmedabad, India, purposively selected by irrigation water type (groundwater, surface water, wastewater), with bimonthly self-reported health diaries and most-probable-number measurement of Escherichia coli in water. Mean E. coli concentrations per 100 mL were 3.04×10^4 (groundwater), 9.28×10^5 (surface water) and 4.02×10^9 (wastewater) — all exceeding international irrigation water standards. Diarrhoea incidence was 7.92 episodes per 1000 person-weeks in the groundwater area versus 13.1 (wastewater) and 13.4 (surface water), with a positive correlation between irrigation water quality and diarrhoea. Wastewater reuse is often promoted as a water-scarcity fix for urban agriculture; this study shows it carries a health cost borne by the farming households themselves.