Research & reports

Ndiaye Awa, Diallo Ibrahima, Dieng Amadou, Ba Ibrahima, Sembene Mbacke · African Journal of Environmental Science and Technology · Senegal

This study in Dakar, Senegal, assessed Salmonella contamination in irrigation water and lettuce across three urban agricultural sites. Sites using wastewater (Pikine and Patte d’Oie) showed high Salmonella prevalence in water (70-90%) and vegetables (20-80%), while a tap water site (Lendeng) had no contamination. Market-sourced lettuce also tested positive (28.57%), indicating public health risks from untreated wastewater use.

María Roo, Cecilia Herbón, Juan Pedro Martín‐Sanz, María Teresa Barral, Remigio Paradelo Núñez · Journal of Soils and Sediments · Spain (Santiago de Compostela)

This study analyzed the chemical extractability and bioaccessibility of five trace metals (Pb, Cu, Zn, Ni, Cr) in 55 urban soils from Santiago de Compostela, Spain, across various land uses. The availability of trace metals in these soils was found to be very low. Plant-available and bioaccessible Cu and Zn were higher in urban garden soils compared to other uses, supporting hypotheses that Cu, Pb, and Zn originate from anthropogenic pollution.

Bahi Aristide Armand, Ohou-Yao Marie Jeanne, Kouamé Leonard Kouadio, Sahiri Grâces Kérène, Akpètou Lazare, Akessé Djamatché Paul, Koné Oumar, Dongui Bini Kouamé · International Journal of Environment and Climate Change · Côte d’Ivoire (Daloa)

This study characterized the physicochemical quality of surface waters at 30 sampling points in lettuce and rice cultivation areas in Daloa, Côte d’Ivoire, from January 2024 to January 2025. Physicochemical analyses revealed spatial variability in water quality parameters, with marked fluctuations influenced by agricultural activities. The findings indicate that surface waters are exposed to contamination from farming practices, domestic activities, and rapid urbanization.

Nelson Joseph Msacky, Amelia Alfred, Oscar Punguti, Edson Protas, Iddi Mapande, Novatus, Shukrani Phillip, January G Msemakweli · Open MIND · Global

This systematic review aims to synthesize current scientific evidence on the effectiveness of fruit-waste-derived biochar in immobilizing potentially toxic elements (PTEs) in contaminated agricultural soils. It will evaluate how fruit-waste biochar reduces metal bioavailability, plant uptake, and associated human health risks from vegetable consumption. The review also seeks to identify which fruit wastes are used as biochar feedstocks and which biochar properties and production conditions influence immobilization performance, noting that existing research is fragmented.

Aulia Maulida, Syafitri Jumianto, Riris Lindiawati Puspitasari, S.Si., M.Si · Prosiding Seminar Nasional Pemberdayaan Masyarakat (SENDAMAS) · Indonesia (Jakarta)

This study examined cattle manure from an urban farm in South Jakarta for the presence of Escherichia coli resistant to third-generation cephalosporins. Using total plate count, selective culture, Gram staining, and biochemical identification, presumptive ESBL-producing E. coli strains were detected. Bacterial growth on cefotaxime-supplemented media indicated phenotypic resistance, demonstrating that urban cattle manure may serve as a reservoir of antibiotic-resistant bacteria.

Jennifer Newell, Rory Doherty, Gary Lyons, Siobhan F. Cox · Environmental Geochemistry and Health · Global

A controlled experiment investigated the effects of 5%w/w digestate biochar on lead (Pb) ingestion risks in urban vegetable agrisystems with varying soil Pb concentrations, high pH, and organic matter. Biochar significantly reduced soil-derived Pb ingestion risks in some systems but had no effect on vegetable-derived Pb ingestion risks for any agrisystem. Overall, biochar showed limited and variable effects on reducing Pb ingestion risks, suggesting its remediation potential is context-dependent and may offer limited protection in soils with elevated pH and organic matter.

Candice M. Duncan, Fatemeh Ghezelsofla, Hlengilizwe Nyoni, Jazmin Escobar, Odette Mina · Toxics · United States

A study measuring per- and polyfluoroalkyl substances (PFAS) in irrigation water at two organic farms in Maryland, USA, with no known direct PFAS input, and assessing health risk via a Hazard Index (HI). At agricultural site 1 (AG1), the most abundant compounds were PFBS (37 ng/L), PFBA (24 ng/L) and PFHxA (22 ng/L); the HI showed compliance for branched PFHxS (0.39) but non-compliance for linear PFHxS (1.51). At agricultural site 2 (AG2), despite no known industrial or PFAS-related facilities nearby, HFPO-DA (GenX) was detected at 28 ng/L, and the HI exceeded the compliance threshold (HI = 2.83), with GenX accounting for most of the calculated risk. The findings show HI exceedances occurring at small farm sites with no identifiable contamination source.

Aminu Zakariyau, Murtala Rabiu · International Journal of Advances in Engineering and Management · Nigeria (Katsina City)

The potential ecotoxicological impacts of municipal solid waste compost (MSWC) on soil, plants, and humans in urban Katsina, Nigeria, were assessed. Analysis of soil mixtures and plant biomass (maize and beans) revealed high phytotoxicity in beans, while maize considered MSWC as phytonutrients. No statistical difference in non-biodegradable substance concentrations in soils and plants was found, and ecological risk index (ERI) indicated low risk; however, Target Hazard Quotients (THQ) suggested a likelihood of non-carcinogenic effects to the ecosystem.

YAO, Kouadio Assemien François, OUEDRAOGO, Moussa, BROU, Konan Richmond, COULIBALY, Léréyaha, OUATTARA, Ismaïla, N'CHO, Odon Clément, YAO, Koffi Blaise · Zenodo (CERN European Organization for Nuclear Research) · Côte d'Ivoire

Nine groundwater samples were collected in March 2025 from urban farming areas of the Man municipality, western Côte d’Ivoire, to assess their physicochemical and metallic quality. Analysis revealed high concentrations of major ions and nitrites (up to 101.7 mg/L) in the groundwater, exceeding WHO standards. Extreme pollution by cadmium, iron, and zinc was confirmed, with an overall contamination degree of 793.6. These groundwaters are unsuitable for human consumption and require regular monitoring and sustainable water resource management.

Amon Abraham, Andrew G. Mtewa, Chimwemwe Chiutula, Richard Lizwe Steven Mvula, Alfred Maluwa, Fasil Ejigu Eregno, John Njalam’mano · International Journal of Environmental Research and Public Health · Malawi (Blantyre)

This cross-sectional study in Blantyre, Malawi, characterized antibiotic-resistant bacteria (ARB) prevalence in 35 samples from five livestock farms, including manure, soil, and vegetables. It found high contamination, with Escherichia coli dominating pig manure (52%) and farm soil (35%), and Klebsiella pneumoniae contaminating all sample types (up to 67% in home soils, 60% in vegetables). All manure isolates showed sulfamethoxazole–trimethoprim resistance, and vegetables exhibited severe multidrug resistance, including 100% E. coli resistance to gentamicin. Composting for ≤6 weeks did not eliminate ARBs, indicating manure-amended farms are AMR reservoirs.

Laxman Barua, YOGITA ADHIKARI, Kuldeep Naik · International Journal of Agriculture and Nutrition · India (Prayagraj)

This research assessed heavy metal concentrations in agricultural soils near the Naini industrial area in Prayagraj, India, and evaluated remediation strategies. Lead and cadmium concentrations at 0.5 km from the industrial zone exceeded Indian permissible limits (Pb: 67.8 mg/kg vs 50 mg/kg; Cd: 6.4 mg/kg vs 5 mg/kg). A pot trial showed that Brassica juncea removed 34.7% of Pb and 41.2% of Cd, while lime + biochar reduced Pb by 52.4%. A combined approach reduced bioavailable Pb to below the permissible limit.

Pierre‐Alexandre Deyris, Franck Pélissier, Claire M. Grison, Claude Grison · Journal of Hazardous Materials Advances · Global

Herbicide use worldwide has doubled over the past 30 years, and diuron contamination of tropical aquatic ecosystems — affecting food crops such as pineapple — has been reported across Southeast Asia, the Pacific, and Africa. This perspective article examines taro (Colocasia esculenta), a widely cultivated crop whose tubers are consumed locally, as a nature-based means of mitigating diuron impact on tropical aquatic ecosystems through rhizofiltration, i.e., phytoaccumulation of the herbicide by the roots. Analysis of treated tubers found that diuron levels in the tuber core were below recommended European standards, indicating the tubers could remain edible for the local population and confirming compatibility with existing food uses.

Roopika Sivaraman, Haritha Thulaseedharan Nair, Sharmila Krishnan, Perumal Siddhuraju · Soil and Sediment Contamination An International Journal · India (Coimbatore)

This study analyzed biocompost and water samples from four agricultural nurseries in semi-urban Coimbatore, India, for microplastic contamination using density separation and ATR-FTIR. While physicochemical properties met Indian standards, microplastic fragments (85%) and fibers (15%) were found in two biocompost samples (BC-B and BC-C), identifying PMMA, PP, and EVA polymers. No microplastics were detected in samples BC-A and BC-D, but the findings suggest semi-urban agricultural gardening may contribute to microplastic accumulation in terrestrial environments, potentially harming soil and plant health.

Miles P.A. Bate-Weldon, Jill L. Edmondson, Katie J. Field · iScience · Global

This study investigated the effect of urban environmentally relevant concentrations of zinc in soils on nutrient exchange between arbuscular mycorrhizal fungi and pea plants using radio-isotope tracing. It found that at higher zinc concentrations, the transfer of phosphorus from fungi to plants and carbon from plants to fungi dramatically decreased. The results suggest that while urban horticulture has potential for food production, the unchecked presence of contaminants like zinc in urban soils may critically hinder its realization.

Nur Dinie Syahirah Sanusi, Fadhlina Che Ros, Siti Zulaikha Ngah Demon, Ismayadi Ismail, Imad Hamadneh · Journal of Advanced Research Design · Malaysia

This mini-review discusses the extensive use of AB mix nutrients in Malaysian urban farming, noting their role in high yields but also their contribution to significant environmental pollution when overused. Although a survey of local entrepreneurs showed most complied with guidelines for chili plants, intensive use of fertilizers leads to nutrient leaching into the soil, causing environmental pollution and affecting humans, livestock, and microbial life. The review emphasizes the need for controlled nutrient application to prevent soil degradation and groundwater contamination.

Cosimo Dondini, Xavier Úbeda, Giacomo Certini, Marcos Francos · Journal of Soils and Sediments · Spain (Barcelona)

This study analyzed soils from ten urban gardens in Barcelona, Spain, with a special focus on possible contaminants. Irrigation water was also analyzed, and some of the waters contained a high concentration of salts and nitrites, which are listed as a pollutant. While three tests for heavy metals did not attest to significant pollution, other toxic elements not considered in this study could come from road transport gases or the port of Barcelona. Overall, the soil quality was concluded to be suitable for growing vegetables.

Simone Trimmel, Stefan Wagner, Laura Feiner, M. Feiner, Daniela Haluza, Rebecca Hood‐Nowotny, Ulrike Pitha, Thomas Prohaska, Markus Puschenreiter, Philipp Spörl, Andrea Watzinger, Elisabeth Ziss, Johanna Irrgeher · Environmental Science and Pollution Research · Europe

A study of urban gardens in Vienna, Austria, building on a previous study of eleven gardens in the city that found elevated lead (Pb) levels in some soil and plant samples. This work examined the elemental composition of soil and plants from two of the affected gardens one year after compost amendment. ICP-MS analysis of tomato fruit skin, pulp and seeds showed only minor variations in elemental composition unlikely to affect food safety, whereas radishes showed a tendency toward contaminant accumulation in root tips and leaves. Washing lettuce significantly reduced levels of potentially toxic elements including Be, Al, V, Ni, Ga and Tl, underscoring the importance of washing garden produce before consumption; compost amendment was associated with reduced Zn, Cd and Pb levels in radish bulbs. Lead isotope ratios in soil and spinach leaf samples from the earlier study, assessed by MC-ICP-MS, showed a direct linkage between the Pb isotopic signatures in soil and spinach leaves, supporting their use as tracers of Pb sources in the environment.

Anne-Kristin Løes, Sebastian Eiter, Tatiana Rittl · Environmental Sciences Europe · Europe

Using soil data from ten peri-urban case farms near Oslo and Bergen, Norway, this study estimated how quickly potentially toxic element (PTE) concentrations would rise in soil under intensive application of compost or digestate from food waste, composted garden waste, or horse and poultry manure applied annually to meet a theoretical carrot crop's nitrogen, phosphorus and potassium demand. Under this intensive fertilization scenario, Norwegian soil quality limits for PTEs would be reached within 20-85 years, faster in soils with more organic matter, with limits reached first for copper and zinc, both essential micronutrients. The urban waste-based fertilizers were also found to be poorly balanced in macronutrients, with rates covering potassium demand leading to high phosphorus and nitrogen surpluses. The study concludes Norway's PTE regulations are stricter than the EU's and do not support recycling organic matter and nutrients from urban waste.

Myeong Seok Jeong, Mina Lee, Chaw Su Lwin, Kwon-Rae Kim · 한국토양비료학회지 · Korea (Jinju)

This study investigated heavy metal concentrations in soil and crop leaves from 23 urban gardens in Jinju, Korea, to assess suitability for cultivation. While average concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn generally did not exceed Korean guidelines, the Geoaccumulation Index indicated ongoing contamination by Cd, Cu, Pb, and Zn. A significant amount of Pb was introduced into some soils from the atmosphere, and continuous monitoring for heavy metals in urban garden soils is required for food safety.

Bethaney Turner · · Global

This chapter explored human-soil relations in urban home and community gardens through ethnographic fieldwork. While biodiverse soil offers direct health benefits, the presence of contaminated, toxic soils, prevalent in lower socio-economic neighborhoods, was shown to expose inequities in access to safe gardening sites and hinder the realization of potential therapeutic benefits. It argues that the therapeutic benefits of gardens are best realized when humans cultivate attentive relationships with myriad multispecies companions.

Jordi Guimera Garcia, Natalie Bray, Yowhan Son, Aleah L. Butler-Jones, Sara Perl Egendorf, Jenny Kao‐Kniffin · Journal of Urban Ecology · United States (New York City)

In New York City, a study investigated plant growth (tomato, pepper, kale) in soils constructed from four municipal composts mixed with sediments from the NYC Clean Soil Bank, to assess the potential for safe urban agricultural soils. While Clean Soil Bank sediments enhanced plant growth when mixed with BRL compost, they also negatively impacted tomato aboveground biomass production by 29% in LES compost and tomato plant height by 18% in QBG compost, indicating variable effects depending on compost properties.

Issaka Senou · Journal of Applied Biosciences · Burkina Faso

This study assessed heavy metal bioaccumulation in cabbage grown on the Dogona market garden perimeter in Bobo-Dioulasso, Burkina Faso, using a randomized block design with urban solid waste treatments. The results showed high levels of cadmium, copper, and lead in cabbage leaves, with concentrations significantly exceeding WHO standards across all treatments. A critical finding was that consuming this cabbage poses a high health risk to consumers due to significant ingestion of cadmium and lead.

Aikaterini N. Martini, Μ. Papafotiou, Ioannis Massas, Nikoleta Chorianopoulou · Plants · Greece

Origanum dictamnus, a perennial herb endemic to Crete, Greece, was grown at two cultivation sites in Athens — an extensive green roof and ground level next to a moderate-traffic road — in two substrate types at 10 cm depth, to examine growth along with nutrient content (N, P, K, Na) and heavy metal accumulation (Cu, Pb, Ni, Mn, Zn, Fe) in its tissues. Plant growth was favored by the soil substrate but was also satisfactory in the soilless substrate. Cultivation site affected heavy metal accumulation, with higher concentrations found in leaves and flowers at street level, though no differences appeared in roots. Washing reduced heavy metal concentrations only in leaves grown at street level. Substrate type significantly affected manganese concentration in all tissues and iron concentration in roots, with the highest values in the soil substrate. The species could be cultivated on sustainable green roofs, preferably on a soilless substrate to reduce structural weight, but careful selection of the cultivation site was identified as necessary to minimize contamination with environmental pollutants when human consumption is intended.

Sani Abubakar Mashi, Samuel Yakubu, Sofia Yuniar Sani · Asian Research Journal of Agriculture · Africa

A study in the Kubanni basin of Zaria, Africa, evaluated the quality of wastewater used for irrigating urban agriculture soils. The wastewater contained arsenic, iron, chromium, copper, zinc, manganese, and lead. Although concentrations were generally below Nigeria's permissible limits for irrigation, the study noted the metals' tendency to accumulate in soils, raising concerns about potential heavy metal buildup in irrigated soils and crops.

Myeong Suck Jeong, Mina Lee, Chaw Su Lwin, Kwon-Rae Kim · 한국토양비료학회지 · South Korea

This study investigated heavy metal contamination in urban agricultural soils near railway tracks and an industrial complex in Jinju, South Korea, to ensure food safety. While the average heavy metal values did not exceed soil contamination guidelines, some individual soil samples showed concentrations higher than the guidelines. Furthermore, the geoaccumulation index (Igeo) indicated that several soils were contaminated compared to background levels, with Cu, Pb, Zn, and Sb showing the highest contamination. Long-term monitoring of urban vegetable garden soils is recommended.