Research & reports

Haofan Xu, Peng Hu, Hailong Wang, Peter Croot, Zhiwen Li, Cheng Li, Shaowen Xie, Hongyi Zhou, Chaosheng Zhang · Environmental Pollution · China

This study in Gaoming county, China, integrated PMF and K-means clustering to identify sources and contamination patterns of 8 potentially toxic elements (PTEs) in peri-urban agricultural soils. Average concentrations of PTEs were reported, with PMF identifying geogenic, industrial/traffic-related, and agricultural sources. The highest PTE concentrations were found in urbanized zones, confirming significant human impact and underscoring the dual influences of agriculture and urbanization on PTE contamination.

Ebenezer Boahen · Discover Agriculture · Ghana

This study assessed the awareness and practices of 50 purposively selected vegetable farmers along the Accra-Tema Motorway, Ghana, regarding heavy metal contamination from vehicular emissions and its potential health implications. Data were collected through structured questionnaires and one-on-one interviews. Results showed that 96% of the farmers were unaware of heavy metal contamination, though 80% expressed a willingness to discontinue farming near the motorway if they were informed of the risks. Farmers face challenges such as limited access to clean irrigation water and dependence on informal agricultural knowledge. The study highlights the urgent need for targeted educational interventions to raise awareness about the risks of heavy metal exposure and to encourage safer farming practices.

Katja Hombrecher · Gefahrstoffe Reinhaltung der Luft · Germany

A pilot study in Germany investigated the impact of road traffic emissions on food plants grown near roads. Bioindicators like kale, chard, Lollo Rosso, and lettuce were exposed for four weeks at four roadside locations and compared to plants in a garden away from roads. While pollutant levels generally did not exceed background or EU maximum limits, significant traffic-related inputs of PAK 4, antimony, aluminum, chromium, and vanadium, and lesser inputs of copper, iron, and lead were detected compared to the control. The findings indicate a potential contamination risk for certain vegetable plants from road traffic.

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.

Carithers, Jaci, Gowen, Samantha, Jenney, Francis · Digital Commons - PCOM (Philadelphia College of Osteopathic Medicine) · United States (Atlanta)

A study in a Metro Atlanta residence, United States, analyzed lead contamination in soil and plant samples using inductively coupled plasma mass spectrometry (ICP-MS). The research found substantial lead contamination, particularly in areas where crops were grown. Results demonstrated the propagation of lead from contaminated soil into local vegetation over time, with an average level of 143.9 mg/kg, ranging from 5.1 mg/kg to 499.5 mg/kg.

K M Tanjida Islam, Md Shahin Mahmud · Pharmacon Jurnal Farmasi Indonesia · Bangladesh

This study characterized multidrug-resistant (MDR) Shigella flexneri strains from contaminated raw vegetables in Bangladesh, retrieved from the NCBI genome database. Whole-genome sequences of four S. flexneri strains from tomatoes and green chilies in Gazipur and Dhaka were analyzed. The analysis identified 4273 core genes and 44 antibiotic resistance genes, with five essential hub genes (tolC, acrA, emrK, emrB, evgS) identified as high-priority therapeutic targets for compromising MDR mechanisms in food-borne S. flexneri.

Anaïs M. Kipelo, M. Jothilakshmi, Dhafer Mohammed M. Al Salah, Georgette N. Ngweme, Emmanuel K. Atibu, Crispin K. Mulaji, Periyasamy Sivalingam, John Poté · Toxicology Reports · Democratic Republic of the Congo (Kinshasa)

This study examined trace element levels in Brassica pekinensis Lour. from urban gardening sites (Cecomaf and Lutendele) in Kinshasa, Democratic Republic of the Congo, and associated human health risks. Analysis showed that Cr, Cu, Cd, Pb, and Hg concentrations in samples from both sites exceeded FAO/WHO maximum permissible limits. Health risk assessments indicated that Estimated Daily Intake (EDI) values for Cd and Pb exceeded recommended limits, and Target Hazard Quotient (THQ) values exceeded 1 for most metals, suggesting potential non-carcinogenic risks.

K I Safitri, Oekan S. Abdoellah, Budhi Gunawan, P Parikesit · Ethics in Science and Environmental Politics · Global

This qualitative study investigated the commercialization of urban agriculture and its influence on agricultural practices and environmental ethics, engaging 43 participants through observation, interviews, and documentation. Findings showed that global commercialization promotes policies for environmental sustainability, leading to aligned production methods. However, in local contexts, farmers cultivating sloped land without perennial crops often use artificial inputs and contaminated irrigation water, facing constraints from intermediaries.

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.

E.N. Jenkins, John M. Galbraith, Anna Paltseva · SOIL · Global

This study conducted a literature review of 84 publications to evaluate the accuracy, precision, and practicality of Portable X-ray fluorescence (PXRF) as a tool for analyzing heavy metal contamination in urban soils. Urban soils often face contamination with heavy metals like lead and arsenic, and PXRF was shown to achieve reliable accuracy when properly calibrated. PXRF emerges as a viable method for assessing urban soil contamination.

M. J. Ni, Shuai Yan, Ting Li, Zijun Zhou, Xiaojing Liu, Shirong Zhang, Guiyin Wang, Xiaoxun Xu, Yulin Pu, Yongxia Jia, Lan Li · Ecotoxicology and Environmental Safety · China (Chengdu)

This study investigated heavy metal (HM) contamination in urban and peri-urban agricultural soils of the Chengdu Plain, China, using an integrated multi-model approach. Four major HM sources were identified, including natural (30.0%), mixed agricultural and transportation (29.5%), metal smelting (19.4%), and atmospheric deposition (21.1%). Risk assessments revealed that Cd and Hg posed the highest ecological risks, and human health risk assessment indicated unacceptable health risks for children, with non-carcinogenic and carcinogenic risk probabilities reaching 4% and 10% respectively.

Yukarie Ayu Wulandari, Ade Sumiahadi, Dirgahani Putri, Helfi Gustia, Rosdiana · Jurnal AGROSAINS dan TEKNOLOGI · Indonesia (Jakarta)

This study, conducted from March to June 2025 in East Jakarta, investigated heavy metal contamination levels in mustard greens grown through urban agriculture. Mustard green samples were collected from five sub-districts, and lead (Pb) and cadmium (Cd) content was measured. Results showed that Cd absorption in mustard greens was very low, well below national and international maximum standards, but Pb absorption exceeded both national (0.5 ppm) and international (0.3 ppm) maximum permissible standards. No strong correlation was found between air quality and Cd or Pb content in the mustard greens.

Justin B. Richardson, Eric Vukicevich, Eric C. Sirkovich · Bulletin of Environmental Contamination and Toxicology · United States

Soils, sap, and maple syrup were collected from four artisanal maple syrup producers in four suburban areas across the northeastern United States to assess nutrient and trace element concentrations. Soil arsenic and lead concentrations approached or exceeded EPA limits. Sap and syrup arsenic, cadmium, nickel, lead, and zinc concentrations reached or exceeded FDA limits for food.

Izabella Pisarek, Kamila Śmieszkoł, Aleksandra Cichoń, Magdalena Śliwa, Dżoana Latała-Matysiak, Katarzyna Łuczak, Grzegorz Kusza · Journal of Ecological Engineering · Poland

A 2025 study assessed the impact of a railway line on soil quality, particularly heavy metal content, at the "Hutnik" family allotment gardens in Zawadzkie, Poland. Twenty research plots were set out near a forest complex (reference) and near railway infrastructure (a potential emission source), with soil samples collected from a depth of 0-25 cm and analyzed for total zinc (Zn), copper (Cu), lead (Pb), chromium (Cr), and nickel (Ni). Elevated concentrations of copper, zinc, and lead were found in soils close to the railway line, and based on the chemical analysis data, the study concludes that railway transport may pose a greater threat to the environment than previously expected.

Magboul M.S. Siddig, Stephen Boahen Asabere, Abdullah S. Al-Farraj, Eric C. Brevik, Daniela Sauer · Journal of Hazardous Materials Advances · Sudan

This systematic review and meta-analysis examined 76 publications on soil heavy metals in Sudan published between 1996 and 2024, assessing concentrations of 10 heavy metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn) and potential ecological risk index (PERI) across 9 land-use types including urban agricultural, industrial, roadside, tannery, waste dump, rural agricultural, coastal sediment, gold mining, and river sediment areas. Average heavy metal levels across all land uses exceeded common soil ranges, with Cd, Cr, Cu, Hg, Ni, and Pb surpassing WHO/FAO limits. In urban agricultural soils, Cd averaged about 158 times and Hg about 340 times typical background ranges, while industrial, gold mining, and waste dump land uses exceeded a serious ecological risk threshold (PERI greater than 900). Cd and Hg together accounted for over 70% of PERI in waste dump and gold mining sites.

Mwangi Kamau, Wanjiku Otieno · International Journal of Veterinary Sciences and Animal Husbandry · Kenya

This study characterized the physicochemical quality of untreated wastewater from three small-scale slaughterhouses on the outskirts of Nairobi, Kenya, and measured its effect on soil microbiology at 0, 50, and 200 meters from the discharge point during both wet and dry seasons. Wastewater biochemical oxygen demand (BOD5) ranged from 1,840 to 2,620 mg/L and chemical oxygen demand (COD) from 3,410 to 4,870 mg/L, exceeding Kenyan discharge standards by 6- to 10-fold. Total bacterial counts in soil at the discharge point were 2.7 times higher than at 200 m (p<0.001), and total coliform counts were 4.1 times higher (p<0.001). The Shannon-Wiener diversity index rose significantly with distance from the discharge point (1.42±0.14 at 0 m vs. 2.34±0.18 at 200 m; p<0.001), indicating that wastewater irrigation selects for a less diverse, coliform-dominated soil microbial community. Seasonal variation was significant for BOD5 and coliform loading but not for the diversity index.

Álvaro Luis José Reyes Córdova · Horizontes Amazónicos · Ecuador

A bibliographic review of research on water quality in the Puyo River and its tributaries in Pastaza, Ecuador, compiled studies from scientific databases and institutional repositories reporting physicochemical, microbiological, and heavy metal parameters. The main sources of contamination were found to be wastewater discharges, fecal coliforms, and accumulation of heavy metals such as lead and mercury linked to urban, agricultural, and mining activities, with community perception aligning with technical findings as most of the population rated the water poor quality and associated it with health problems. Over the past twenty years, a progressive deterioration in water quality parameters has been documented, with increases in turbidity and pathogenic microorganisms despite some isolated recovery efforts, and the review concludes that lack of attention from the municipality and prefecture, together with the absence of continuous monitoring, is worsening the water crisis and demands comprehensive, participatory governance.

Jacek Antonkiewicz, Iwona Paśmionka, Grzegorz Szychowski · Soil Science Annual · Poland

Following a flood that inundated allotment gardens in Nysa, southern Poland, for up to 14 days after the water rose on 14 September 2024, researchers analyzed 12 soil samples collected in early spring 2025 from two allotment garden sites. Most soils were found limed and disinfected, with high organic matter but low total potassium, sodium and sulfur. Zinc and copper concentrations exceeded the average for Polish arable soils, pointing to use of materials enriched with these elements.

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.

Abubakar Mohd Habu, Ali Sanusi Hassan, Adeniyi Olarewaju Adeleye, Michael Edet Nkereuwem, Ijanu Emmanuel Madu, Garba Barde Bate, Olukemi Adeleye, Usman Mohammed Isah · Biological Environment and Pollution · Nigeria

This study assessed heavy-metal accumulation and non-carcinogenic health risks in commonly consumed leafy vegetables -- lettuce, spinach, and cabbage -- cultivated with wastewater in Zawaciki, Kano State, Nigeria. Vegetable and rhizospheric soil samples were analyzed for cadmium, lead, chromium, nickel, zinc, and copper using atomic absorption spectrophotometry, and bioaccumulation factors (BAFs) were calculated as the ratio of metal levels in plant tissue to soil. Metal concentrations varied significantly across the vegetables (p < 0.05), with lead in lettuce leaves exceeding the FAO/WHO permissible limit by more than 120 times; chromium in cabbage reached 32.22 mg/kg, while lettuce showed elevated zinc (19.83 mg/kg) and copper (9.26 mg/kg). Hazard-quotient risk assessments found HQs for chromium and lead both exceeding 1, and the cumulative hazard index exceeded 1 for all vegetables, reaching its highest value of 18.861 in lettuce.

Md. Rafiqul Islam, Syed Anisur Rahman, Tanvir Ahmed · International Journal of Agriculture and Food Science · Asia

Six heavy metals (lead, cadmium, chromium, nickel, copper, zinc) were measured by atomic absorption spectrophotometry in spinach, amaranth and fenugreek collected from four peri-urban sites around Dhaka, Bangladesh, during January-March 2024, where more than 2,000 hectares of vegetable land are irrigated with untreated industrial and domestic wastewater via canal networks. Lead in amaranth from the industrial-effluent site reached 0.94 mg/kg fresh weight, more than three times the WHO/FAO permissible limit of 0.30 mg/kg, while cadmium, chromium and nickel stayed within permissible limits at all sites and zinc, though highest in absolute terms (8.6-14.7 mg/kg), also remained within safe limits; contamination was highest at the industrial-effluent site and lowest at the borewell-irrigated control site, indicating a localized food-safety risk for consumers of peri-urban leafy greens grown with wastewater irrigation.

Jarosław Chmielewski, Barbara Gworek, Alicja Walosik, Magdalena Florek-Łuszczki · Annals of Agricultural and Environmental Medicine · Poland

Soil (N=196) and root vegetable (N=94) samples from 16 allotment gardens in Warsaw, Poland, were analyzed for manganese, zinc, copper, lead and cadmium and assessed for health risk. Parsley, carrots, beetroots and celery grown in these gardens accumulated elevated levels of all five metals, and the health risk assessment found an increased risk of carcinogenic effects from cadmium and lead in consumers of these root vegetables; the authors conclude consumption of vegetables from the examined gardens should be very limited or eliminated from the diet entirely.

Ikrema Hassan, Innocent Mugudamani, Saheed Adeyinka Oke · Environments · Canada

Top and subsoil samples from Carleton community garden in New Brunswick, Canada, affected by an industrial fire hazard, were analyzed for toxic heavy metals using ICP-OES and ICP-MS, with ecological risk assessed via the ecological risk factor and potential ecological risk index (PERI) and human health risk assessed using a standard approach. Mean concentrations of lead, zinc, copper and tin exceeded permissible limits under Canadian soil quality guidelines and upper continental crust values; nickel posed a high ecological risk across both soil layers while all other metals showed low ecological risk, and overall PERI indicated low ecological threat. In the human health assessment, children faced non-carcinogenic and carcinogenic risk from arsenic exposure while adults did not face risk from any of the metals studied, identifying arsenic as the primary contaminant of concern and children as the most vulnerable population.

Jennifer Newell, Siobhan Cox, Rory Doherty · Urban Agriculture & Regional Food Systems · Global

A systematic review synthesized literature on the oral bioaccessible fraction (BAF) of arsenic, cadmium, chromium, nickel, and lead in vegetables grown on contaminated soils, drawing values from multiple online databases across potentially toxic elements (PTEs), in vitro test methods, and vegetable types. The review starts from the premise that many urban and peri-urban brownfield sites carry a legacy of soil metal and metalloid contamination, so crops grown there may pose human health risks. Median PTE BAFs ranked Cd > Ni > Cr > As > Pb; among in vitro methods, the unified BARGE method (UBM) produced the highest median BAFs (63.0% gastric, 59.6% gastrointestinal); and by crop type, BAFs ranked non-vegetables (e.g., rice, fungi) > legumes > root vegetables > bulb vegetables > leafy vegetables.