Research & reports

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.

Adam Abraham · Jurnal Riset Daerah · Indonesia

This study aimed to identify the impacts of land use change experienced by urban farmers in Kapanewon Kasihan, Indonesia. Using a deductive-qualitative approach, it was analyzed that urban development has both positive and negative impacts on farmers. The most significant negative impacts included pollution, decreased productivity, and the squeezing of urban agricultural land, which could lead to long-term environmental quality degradation and further spread of land use change.

Annie Stéphanie Nana, Timo Falkenberg, Andrea Rechenburg, Annet Adong, Anne Ayo, Pierre Nbendah, Christian Borgemeister · Agriculture · Cameroon

This study investigated factors influencing farming practices and disease prevalence among 130 vegetable producers in the lowlands of Yaoundé, Cameroon, through a cross-sectional survey. Education level and farm size were positively associated with overall fertilizer use, while pesticide usage was positively associated with years cultivated but negatively with land ownership. Waterborne disease prevalence was linked to education level, and malaria prevalence to farmer gender. The location of cultivated areas significantly influenced reporting malaria and headaches, concluding that despite associated health risks, vegetable production is necessary for farmers’ livelihoods.

Noëllie W. Kpoda, Hamidatu S. Darimani, Adama Ouéda, Idrissa Ouédraogo, Gustave B. Kabré · Agricultural Sciences · Burkina Faso (Ouagadougou)

This study evaluated the risk of parasitic infection among vegetable producers in Ouagadougou, Burkina Faso, who use polluted water, employing a quantitative microbiological risk assessment method. Protozoa and helminths from 9 species were detected in irrigation water, with Ancylostoma sp. eggs being common and severe across all water types. Contamination risk was higher for groups using raw wastewater than for those using well water, and halved for those using treated wastewater; however, regardless of water type, gardeners had an approximate 9.83 × 10−1 pppy probability of Ancylostoma sp. infection.

Laura Boluspayeva, Monika Jakubus, W. Spychalski, Akhan Abzhalelov, Yertas Bitmanov · International Journal of Environmental Research and Public Health · Kazakhstan (Oskemen)

This study investigated heavy metal contamination in soils and vegetables due to the metallurgic industry in industrial areas of Oskemen, Republic of Kazakhstan. The greatest amounts of metals were found in soils and vegetables from the industrial zone, with the lowest in the suburban zone. Lead concentrations exceeded WHO/FAO standards in all analyzed vegetable samples, leading to the conclusion that consumption of vegetables cultivated in industrial areas should be restricted due to health risks.

Anithadevi Kenday Sivaram, Logeshwaran Panneerselvan, Aravind Surapaneni, Elliot Lee, Kurunthachalam Kannan, Mallavarapu Megharaj · Environmental Advances · Australia

This study assessed 19 commercially available composts, garden soils, and potting mixes in Australia for 38 per- and polyfluoroalkyl substances (PFAS). Total PFAS concentrations ranged from 1.26 to 11.84 µg kg−1 (dry weight), with total perfluorinated carboxylic acids (ƩPFCAs) being higher than perfluoroalkyl sulfonic acids (PFSAs). The total oxidizable precursor assay (TOPA) showed an increase in short-chain ƩPFCAs (0.48 to 7.63 µg kg−1) in composts and potting mixes, indicating transformation of PFCAs precursors. The measured concentrations of short-chain PFCAs in soil substrates have the potential to contribute to plant uptake and food chain transfer of PFAS to humans.

Maurice Kesonga Nsele, Jules Nkulu Mwine Fyama, Kevin Maréchal, Thomas Dogot · Agriculture · Democratic Republic of Congo (Lubumbashi)

In urban agriculture in Lubumbashi, Democratic Republic of Congo, an innovative technology package was disseminated, but ten years later, farmers' daily income was less than USD 1.25, and critical exceedances of heavy metal content standards in crops were recorded. Survey data from 202 farmers and a Logit model identified factors influencing the sustained adoption of two innovations: motor pumps and integrated soil fertility management. Socio-demographic factors were not significant for motor pump adoption, and only mutual aid moderately influenced integrated soil fertility management. Economic factors like land tenure and income diversification were significant for motor pump adoption, but no economic factors were significant for integrated soil fertility management. Institutional factors such as access to credit and association membership were significant for the sustained adoption of both innovations.

Ainsley C. McStay, S.L. Walser, Eric C. Sirkovich, Nicolas Perdrial, Justin B. Richardson · Journal of Environmental Quality · United States

This study evaluated portable X-ray fluorescence (pXRF) measurements of macronutrients, micronutrients, and toxic elements (As, Pb) in soils and plants from 10 urban community gardens across the eastern United States. It found that pXRF and traditional methods provided agreeable estimates for some elements (Mn, Cu, Zn, Pb) but not for macronutrients (Ca, K, P). While pXRF is an accurate tool for screening Mn, Cu, Zn, and Pb, macronutrients were poorly estimated in fruits, leaves, and roots, and genus-specific and garden-specific factors may be important for plant uptake models.

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.

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

In Katuba municipality, Lubumbashi, Democratic Republic of Congo, irrigation water, soil, and harvested amaranth from an area of urban amaranth cultivation were analyzed for chemical and microbiological pollutants. Water and amaranth were polluted on both mineral and microbial fronts, while soil was not; water samples contained Paramecia, Entamoeba histolytica eggs, fecal contamination indicator germs, mesophilic flora, and pathogens including Aeromonas hydrophila and Pseudomonas aeruginosa. Amaranth cobalt concentrations exceeded quality standards and the plants were contaminated with Paramecia, Entamoeba histolytica eggs, Escherichia coli, and Klebsiella planticola, leading to the conclusion that consuming these amaranths poses health risks to the population.

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.

Peter Sanjo Adewale, Sunday Clement Olubunmi Makinde, V. Kusemiju, Olawole O. Obembe · Journal of sustainability and environmental management · Nigeria

This study measured and compared lead (Pb), cadmium (Cd) and manganese (Mn) concentrations in soil and leafy vegetables (Amaranthus hybridus, Celosia argentea, Corchorus olitorius) using atomic absorption spectrophotometry at Urban Expressway Farms (UEF) and Peri-urban Road Farms (PRF) in Lagos State, Nigeria. It found the highest Pb concentration (0.93+/-0.06) in Celosia argentea at UEF, and the highest Cd (0.51+/-0.11) and Mn (0.98+/-0.02) concentrations in Amaranthus hybridus at UEF, with Pb in Celosia argentea 5 m from the expressway and Cd in Amaranthus hybridus 10 m from the expressway exceeding WHO/FAO permissible levels; heavy metal residue levels were driven more by farm location than by vegetable type, and the study calls for regular monitoring to prevent consumption of contaminated leafy vegetables and recommends farmers cultivate fields farther from expressways.

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.

Michael Hardman, Andrew Clark, Graeme Sherriff · Agronomy · United Kingdom

Using a qualitative approach across the UK's largest urban farm and a range of other urban agriculture (UA) sites, this study examined the barriers to upscaling city farming. Evidence pointed to urban soil contamination and hesitation about growing crops in cities as a core issue preventing UA from scaling up, alongside public hesitancy and financial barriers, despite the practice's potential social, environmental and economic value through job creation, biodiversity enhancement and shorter food supply chains. The paper concludes that public hesitation, financial barriers and soil quality prevent development, and calls for a more pragmatic approach to these barriers.

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.

Hoda Fakour, Shang‐Lien Lo, Nathan Thadeo Yoashi, Angelbetter Marselian Massao, Nelson Naboth Lema, Fezile Bethusile Mkhontfo, Patrick Chris Jomalema, Nasra Shabani Jumanne, Bright Hubert Mbuya, James Travor Mtweve, Moslem Imani · Agriculture · Taiwan (Tainan)

A study in Tainan city farms, Taiwan, quantified and analyzed microplastics (MPs) in farmland soils. MPs were found in all soil samples at depths ranging from 12–117 items/m2. Farms adjacent to suburban roads had approximately three times more MPs than enclosed farms. Fragment and fibers were the main forms, with low-density polyethylene being the dominant polymer, originating from historical land use, plastic mulch, and fruit protection foams.

Sabina Rossini Oliva, Rafael López Núñez · Agronomy · Spain

This study investigated potential toxic element contamination in food and soils from urban and rural gardens in Seville, Spain, including urban gardens in a mining area. Soils from mining gardens were the most contaminated. While arsenic, cadmium, and lead concentrations in studied vegetables did not exceed legal maximum levels, high levels of barium (up to 42 mg kg−1) and zinc (up to 123 mg kg−1) were found in leafy green vegetables like chard and lettuce, indicating a need for further study on associated human health risks.

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.

Marta Crispo, Miriam C. Dobson, Roscoe S. Blevins, William Meredith, Janice A. Lake, Jill L. Edmondson · Environmental Pollution · United Kingdom

Heavy metal (HM) and metalloid concentrations were assessed in 200 urban horticultural soils across ten UK cities. HM were found to be widespread, with most concentrations below UK soil screening values (C4SLs). However, 83% of lead (Pb) concentrations exceeded C4SLs, which is a significant concern. Bioavailable HM concentrations represented a small fraction (0.01–1.8%) of total concentrations, and black carbon (BC) and organic carbon (OC) were suggested to contribute to HM immobilization.

Seema Purushothaman, Sheetal Patil, Raghvendra S. Vanjari, A. R. Shwetha · · India (Bengaluru)

A participatory assessment in Byramangala, Bengaluru, explored farmers' perspectives on using wastewater (domestic sewage with industrial effluents) for irrigation. The study found that farmers were adapting to a heavily polluted environment, which resulted in restricted crop choices, lower produce prices, health impacts, and socio-cultural consequences. Despite concerns about water quality, farmers prioritized health-imparting agriculture and were keen to continue farming, but their preference for treated wastewater was overshadowed by its potential diversion for urban use.

K. K. Dey, Maria Velez-Climent, P. Soria, Özgur Batuman, Vessela Mavrodieva, Guo Wei, Jun Zhou, Scott Adkins, John D. McVay · New Disease Reports · United States (Florida)

In October 2019, Tomato brown rugose fruit virus (ToBRFV) was detected in six of eight symptomatic tomato plants from a 1.6 ha community garden in Alachua County, Florida. The plants also showed symptoms of Tomato yellow leaf curl virus (TYLCV), with three samples testing positive for TYLCV. This marks the first report of ToBRFV infecting tomatoes in Florida, USA.

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.