Research & reports

Elżbieta Skorbiłowicz, Piotr Ofman, Mirosław Skorbiłowicz, Marcin Sidoruk, Urszula Tarasiuk · Water · Poland

This study assessed heavy metal contamination in 96 surface sediment samples collected from urban, agricultural, and forested areas of the Bug River catchment in Poland between July 2018 and 2020, measuring metals (Zn, Pb, Cr, Ni, Cu, Fe, Mn, Cd) by atomic absorption spectroscopy and applying the geoaccumulation index (Igeo), contamination factor (CF), and pollution load index (PLI). Urban sediments showed significantly higher heavy metal concentrations than agricultural or forested areas, with cadmium reaching up to 2.5 mg/kg; the average Igeo for cadmium was 0.24 in agricultural areas and 0.15 in urban areas, while the highest PLI values, reaching a maximum of 0.33, occurred in urban areas, and statistical analysis showed both urban emissions and agricultural activities significantly influenced heavy metal presence in the sediments.

Arcadius Martinien Agassin Ahogle, Sammy Letema, Gertrud Schaab, Veronica Ngure, Abraham R. Mwesigye, Nicholas Kibet Korir · Frontiers in Soil Science · Kenya (Nairobi)

This study assessed heavy metal and trace element contamination risks in peri-urban farmlands in Nairobi city catchment, Kenya, by analyzing 60 soil samples from ten vegetable farming zones. Results showed elevated concentrations of elements including As, Cd, Mn, Pb, and Zn, with some exceeding permissible agricultural thresholds. As, Cd, Hg, and Pb exhibited high ecological risks, with Cd contributing 46-66% of the overall risk.

Mansi I. Bhati and R.K. Dubey · Zenodo (CERN European Organization for Nuclear Research) · Global

Urban horticulture, a new concept for growing family-sufficient food in urban and peri-urban areas, is gaining importance. However, environmental challenges for urban farming in urban environments include soil contamination, micro-climate alteration and air pollution, and contaminated water resources. Appropriate guidelines for urban and peri-urban agricultural practices are required.

Naoual Zerrari, Naoual Raïs, Mustapha Ijjaali · Soil and Sediment Contamination An International Journal · Morocco (Fez)

Nine soil samples from agricultural soils in Fez-Upstream, Morocco, were analyzed to assess concentrations of major elements, Rare Earth Elements (REEs), and heavy metals. The soils were enriched by light REEs, and the contamination factor and degree of contamination indicated moderate and low contamination, respectively. However, all sampling sites showed PLI values above 1, indicating obvious anthropogenic pollution due to human activities.

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.

Subhash Aswal, Harshal Purohit, P. K. Gupta, K. K. Yadav, Laxman Jat, Shipra Jaiswal, R. A. Kaushik · International Journal of Plant & Soil Science · India (Kota)

A quarterly survey in Kota district, Rajasthan, India, characterized wastewater-irrigated soils by comparing them with tube well water-irrigated soils from ten urban sites. The study found decreased sand content, pH, and dehydrogenase activity, while porosity, EC, BOD, COD, OC, available-NPK, SO4, Cl, and heavy metals (Mn, Fe, Zn, Cu, Ni, Cd, Pb, Cr) increased. Some parameters exceeded Indian standard permission limits, indicating contamination, with highest values observed in summer.

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.

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.

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.

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.

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.

Xingjia Wang, Wenbo Li, Dongyan Wang, Songze Wu, Zhuoran Yan, Jiaqi Han · Ecological Indicators · China

A 'trinity' assessment method was developed to evaluate heavy-metal contamination in peri-urban soil–crop systems in Northeast China, covering total, available, and accumulated heavy metals. While traditional methods indicated less contamination, the trinity method revealed spatial clustering of heavy-metal contamination in cultivated lands caused by urbanization and industrialization, and a decreasing urban–rural trend in contaminated areas, particularly in transition zones.

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.

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.

Mila Siti Fatimah, M.S Ir. Eko Hanudin, Ph. D. Toru Watanabe · · Vietnam

This study investigated heavy metal contamination in soils, vegetables, and irrigation water in peri-urban agricultural areas of Hue, Vietnam, from May 2018 to January 2019. Samples from three sites revealed that while irrigation water and agricultural soils were not seriously contaminated, 14% of vegetables were contaminated by Cr, 76% by Cd, and 47% by Pb. The consumption of vegetables was categorized as a tolerable health risk.

Małgorzata Ćwieląg‐Drabek, Agata Piekut, Klaudia Gut, Mateusz Grabowski · Scientific Reports · Europe

A study of family allotment gardens (FAGs) in Silesia Province, one of the most polluted regions in Poland, analyzed 219 soil samples and 64 edible plant samples to link the geochemical disturbance caused by past mining and smelting activity to consumer exposure to toxic and carcinogenic metallic trace elements. Contents of these elements in topsoil were spatially diverse and depended primarily on the location of industrial pollution sources. Average cadmium (0.52 mg/kg fresh weight) and lead (0.57 mg/kg fresh weight) content in vegetables exceeded maximum permissible concentrations under European quality standards. A human health risk assessment based on three dietary exposure scenarios found that, in every scenario, potatoes — a staple of the Polish diet — carried the highest average daily dose for all three elements. The study concludes that consuming vegetables grown in Silesia Province's family allotment gardens may pose a significant health risk to consumers.

Joseph Richmond Fianko, Mavis Korankye · West African Journal of Applied Ecology · Ghana

A study assessed the environmental and health impact of urban and peri-urban irrigated agriculture in Ghana by analyzing the physico-chemical and microbiological characteristics of irrigation water in the Greater Accra Region, calculating a comprehensive pollution index (CPI) and sodium adsorption ratio (SAR). Water samples used for informal irrigation contained significant microbial loads: total coliform ranged from 25×10² to 1209×10² cfu/100ml and E. coli from 2×10² to 651×10² cfu/100ml, with a mean total coliform level (517.917×10² cfu/100ml) far exceeding the recommended maximum guideline values of 5,000 and 1,000 cfu/100ml for irrigation water. CPI values ranged from 0.16 to 0.43 (average 0.27), indicating moderate pollution; about 42% of samples were classified as sodic waters, and SAR values of 3.42 to 24.75 meant nearly all samples exceeded the threshold (SAR > 4) associated with reduced water infiltration and soil permeability problems. The water is described as under persistent pollution pressure from expanding human activity, posing high risks to the health of the environment, farmers, traders, and consumers.

Anna Margenat, Víctor Matamoros, Sergi Dı́ez, Núria Cañameras, Jordi Comas, Josep M. Bayona · Environment International · Spain (Barcelona)

A study assessed 16 trace elements and 33 organic microcontaminants in lettuce, tomato, cauliflower, and broad beans from peri-urban farms near Barcelona, Spain, and a rural site. Concentrations ranged from non-detectable to 17.4 mg/kg for trace elements and non-detectable to 256 μg/kg for organic microcontaminants, with tomatoes showing the highest levels. Risk assessment indicated a low human health risk from consuming these vegetables in the peri-urban area, comparable to the rural site.

· Journal of Animal and Plant Sciences (J Anim Plant Sci ) ISSN 2071 – 7024 · Africa

A study in Port-Bouët, Abidjan, examined market gardeners' phytosanitary practices and pesticide residue incidence on lettuce. It found that 39.6% of pesticides used were not recommended for market gardening, 86.84% of gardeners did not protect themselves during application, and 80.26% did not observe pre-harvest intervals. Consequently, 93.33% of lettuce samples did not comply with Codex Alimentarius and EU standards due to high pesticide residue contamination.

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.

Camille Dumat, Antoine Pierart, Muhammad Shahid, Sana Khalid · · Global

Urban agriculture, while a strategy for sustainable food production, faces a serious threat from natural and anthropogenic pollution sources in urban and peri-urban environments. These sources release hazardous organic and inorganic contaminants, leading to a high likelihood of human exposure. Consumption of vegetables grown on polluted urban soils or those that have intercepted metal-rich atmospheric particles represents a potential route of pollutant exposure and human health hazard.

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.

Anne Barbillon, Christine Aubry, François Nold, Stéphane Besançon, Nastaran Manouchehri · Agricultural Sciences · France

This study assessed health risks from soil trace metals (lead, cadmium, mercury, copper, and zinc) at three urban farms near Paris (Ile-de-France region), evaluating two main exposure pathways: soil and vegetable ingestion. All three farms had soil trace-metal levels above geochemical background values and the thresholds used in France as reference values for sludge spreading. Using a Hazard Quotient (HQ)-based risk assessment (HQ being the ratio of estimated daily intake to tolerable daily intake), the riskiest scenarios were urban farmers working on-site daily year-round (HQtot = 1.02), child gardeners (HQtot = 1.29), and regular child consumers eating exclusively the farm's vegetables under a maximalist scenario (HQtot = 1.6). The adult gardener scenario followed (HQtot = 0.9), while the lowest-risk scenarios were adult consumers (HQtot = 0.62) and farm workers (HQtot = 0.45).

Wojciech Mrozik, Soydoa Vinitnantharat, Thunchanok Thongsamer, Nipapun Pansuk, Pavinee Pattanachan, Parinda Thayanukul, Kishor Acharya, Marcos Quintela‐Baluja, Charles R. E. Hazlerigg, Aidan Robson, Russell J. Davenport, David Werner · The Science of The Total Environment · Asia

A study of three family-owned peri-urban aquaculture operations downstream of Bangkok, Thailand — spanning extensive, semi-intensive and intensive practices — used micropollutant analysis, genetic markers and 16S rRNA amplicon sequencing to assess water quality against aquaculture standards. Canals draining Bangkok did not meet quality standards and were sources of faecal coliforms, Bacteroides, Prevotella, human E. coli, tetracycline-resistance genes and nitrogen entering the ponds, causing algae blooms. The aquacultures in turn discharged salinity and the herbicide diuron into the canals; diuron was detected in shrimp, though not at a level of concern to human health. The extensive aquaculture attenuated an estimated 20 population equivalents of nitrogen pollution and trillions of faecal coliform inputs per year.

Dan Li, Chun Hong Wong, Mei Fang Seet, Nicole Kuan · Frontiers in Microbiology · Singapore

This study conducted, for the first time to the authors' knowledge, an investigation of Stenotrophomonas maltophilia -- an emerging opportunistic pathogen capable of causing high-mortality nosocomial infections in immunocompromised patients while also being ubiquitous in the environment -- on leafy green vegetables and in a hydroponic farming facility in Singapore. Eleven isolates were recovered from three vegetable types (sweet basil, kale, parsley) and the nutrient solution, with high population levels reached in vegetables under abused storage temperatures (over 8-log CFU/ml in basil juice after six days at 20°C) and on hydroponic facilities through biofilm formation (8 to 9-log CFU/well), and UV treatment (over 4-log reduction at 250 mJ/cm²) was identified as an effective measure to reduce contamination in nutrient solutions and facilities.