Research & reports

Sandeep Kumar, Lal Chand Malav, ICAR- National Bureau of Soil Survey & Land Use Planning, Nagpur, 440033, Maharashtra, Shiv Prasad, Sunita Yadav, Amrita Daripa, ICAR- National Bureau of Soil Survey & Land Use Planning, Nagpur, 440033, Maharashtra · Agropedology · Global

This review argues that rapid industrialization and mechanization are driving heavy metal pollution worldwide, with both anthropogenic and natural sources of heavy metals reaching soil, water bodies and plants and ultimately entering the human body through the food chain. Heavy metals accumulate in plants and living organisms after uptake from soil and cause harm, and they are also toxic to soil biological activity by disrupting key microbial processes. The review states that, due to industrial development in urban areas, heavy metal contamination — from metals such as zinc, copper, lead and cadmium — has become a serious threat to the peri-urban agriculture that supplies vegetable production, and it surveys sources of contamination and remediation techniques, with a particular focus on phytoremediation.

Anne Barbillon, Christine Aubry, Nastaran Manouchehri · HAL (Le Centre pour la Communication Scientifique Directe) · France

This French guide, "R.E.F.U.G.E.," developed by AgroParisTech, sets out a four-step methodology to help urban-planning actors in the Île-de-France region assess and manage soil contamination risk before establishing urban agriculture on available land: a historical and environmental site study, a sampling strategy, interpretation of soil analyses, and, where warranted, a formal health risk assessment. Based on France's national methodology for managing polluted sites and soils, it is intended as a first harmonized technical tool for the field and was slated for a testing phase applying it to future urban agriculture projects. The abstract itself does not report contamination measurements or findings from any specific site; it describes the assessment procedure rather than presenting soil contamination data.

P.S. Bouda, Edmond Hien, A. Dioma, Hyacinthe Kambiré, Yacouba Maïga, Der Adolphe Somé, Sylvie Nazaret, A.S. Ouattara · DOAJ (DOAJ: Directory of Open Access Journals) · Burkina Faso

A study in Ouagadougou sub-urban agricultural fields, Burkina Faso, assessed the impact of using untreated Solid Urban Wastes (SUW) as agricultural fertilizers on soil properties and crop production. SUW amendment significantly increased pH, total C, N, P, and available P, and maize height and biomass yield were 124% and 164% higher in amended plots, respectively. However, trace metal elements (Cu, Zn, Pb, Ni, Cr) concentrations were higher in amended fields, indicating that urban waste carries contaminants posing public health risks.

Piotr Krzyk, Bogusława Kwoczyńska · Problemy Drobnych Gospodarstw Rolnych / Problems of Small Agricultural Holdings · Poland (Cracow)

This study quantitatively assessed the conversion of agricultural land to investment purposes in Cracow's Mogiła and Wyciąże neighborhoods from 2010-2013, based on local plans. It also addressed soil quality, heavy metal content, and pH. Analysis of spatial management plans for these areas indicated a systematic decline in the share of biologically active areas.

Mireia Ercilla‐Montserrat, Pere Muñoz, J.I. Montero, Xavier Gabarrell, Joan Rieradevall · Journal of Cleaner Production · Spain (Barcelona)

This study measured heavy metal content in air and hydroponic lettuce leaves at four sites in Barcelona, including high-traffic areas, to assess potential contamination from atmospheric pollution. The results showed that heavy metal concentrations in lettuce leaves were below EU-legislated limits in all cases, and air concentrations were less than 50% of legislative limits. The study concluded that Barcelona's air heavy metal content is low and not a source of contamination for urban crops, even near high-traffic areas.

M. L. Dotaniya, V. D. Meena, S. Rajendiran, M. Vassanda Coumar, Asha Sahu, J. K. Saha, S. Kundu, Hiranmoy Das, A. K. Patra · Journal of the Indian Society of Soil Science · India (Bhopal)

A case study in peri-urban agricultural lands near Patranala, Bhopal, India, investigated the impact of over 50 years of untreated sewage water irrigation on soil properties. Findings showed higher concentrations of heavy metals in surface soils of sewage-irrigated fields, posing a major concern. Conversely, soil microbial population, enzymatic activities, and organic carbon content were also higher, indicating enhanced carbon sequestration.

Muhammad Asif Khan Rai Muhammad Amir · International Journal of Biosciences (IJB) · Pakistan (Faisalabad)

To investigate heavy metal residue levels in cauliflower grown in the peri-urban area of Faisalabad district, Pakistan, 30 cauliflower samples were collected from 10 selected farmers. Analysis revealed variable heavy metal residue levels (nickel, lead, zinc, copper, arsenic, and mercury) in the samples, indicating that the cauliflower was contaminated with multiple heavy metals. This contamination is attributed to the use of untreated sewage water for cultivation, which is the single largest contributor to heavy metal accumulation in cauliflower.

Dan Luo, Haifeng Zheng, Ye Chen, Philippe Deleporte, Tianpeng Xie, Siobhán Staunton, G. Wang · Soil Use and Management · China (Fujian Province)

A large-scale survey across 515 sites and 24 crop species in Fujian Province, SE China, assessed nickel (Ni) accumulation in food crops and associated dietary health risks. Crop Ni content was influenced by both soil Ni (DTPA-extractible) and plant species, though PCA did not show strong correlations between soil-to-crop transfer factors and soil properties. The study concluded that dietary intake of foods with mean Ni content could lead to health risks, particularly for children, and that sandy soils rich in organic matter with high Ni content are unsuitable for growing rice and legumes.

Jacques Godfroid · Archives of Public Health · Global

This opinion paper discusses a One Health approach to brucellosis at the wildlife-livestock-human interface in both industrialized and low- and middle-income countries. It points to pitfalls in serological studies and states that urban and peri-urban farming contributes to the re-emergence of brucellosis in the developing world, identifies wildlife as a potential reservoir, and discusses the ethics of culling wildlife to control disease spread.

Ojuolape F. Akande, S. A. Ajayi · International Journal of Environment Agriculture and Biotechnology · Nigeria

This study measured heavy metals (As, Cd, Cu, Pb, Zn) in soil and in amaranth (Amaranthus hybridus) and jute mallow (Corchorus olitorius) vegetables from selected peri-urban farms around Osun State, Nigeria, to assess human health risk. Soil concentrations fell within FAO/WHO (2002) and EU (2006) agricultural background ranges, but vegetable samples showed appreciable metal levels; arsenic was below detection in all samples, amaranth showed higher retention than jute mallow for all metals except copper, the transfer-factor order was Cd > Zn > Pb > Cu, amaranth contributed the highest estimated daily intake for Cd, Cu, Pb and Zn, the health risk index was high for Cd and Pb but low for Cu and Zn, and the hazard index results indicate that vegetables grown on the selected peri-urban farms are not safe for consumption.

Godswill Azinwie Asongwe, Bernard Palmer Kfuban Yerima · Greener Journal of Soil Science and Plant Nutrition · Cameroon (Bamenda)

This study analyzed heavy metal levels (chromium, manganese, lead, cadmium) in 21 urban and peri-urban agricultural wetland soil samples in Bamenda municipality, Cameroon. Average concentrations were 35.73 mg/kg for chromium, 0.08 mg/kg for manganese, 30.64 mg/kg for lead, and 0.45 mg/kg for cadmium. These concentrations were generally lower than the maximum WHO permissible levels.

Kamal Kishore Yadav, Pradeep Kumar Singh, R. C. Purohit · Water science and technology library · India (Udaipur)

A study in the peri-urban area of Udaipur City, India, investigated heavy metal contamination in soil, vegetable crops, and groundwater due to wastewater reuse. While groundwater-irrigated vegetables showed heavy metal levels within WHO limits, wastewater-irrigated spinach, tomato, and radish at site 3 (Kanpur – Madri Villave) exceeded maximum permissible limits for Fe, Zn, and Cd. Urban wastewater-irrigated spinach was found to accumulate Fe, Zn, and Cd significantly above permissible limits at all three selected locations, making it unsafe for human consumption.

Isaiah Sewanu Akoteyon, Adeyemi Davidson Aromolaran · International Journal of Environment and Sustainable Development · Nigeria (Lagos)

This study evaluated peri-urban market gardening and shallow well water quality for irrigation in Lagos, Nigeria. It found that the mean values of bicarbonate, calcium, and pH in shallow wells exceeded detection levels in 66.7%, 60%, and 53.3% of samples, respectively. Salinity and sodium hazard patterns showed that approximately 66.7% of shallow wells had low salinity, 26.7% medium, and 6.7% high.

Joshua Oluwole Olowoyo, Gladness Nteboheng Lion · South African Journal of Science · South Africa

This review reports on the concentrations of trace metals in crops, including leafy vegetables, harvested from various urban areas. It highlights the presence of trace metals in leafy vegetables and discusses various pathways of uptake, possible health risks associated with urban farming, and morphological and physiological impacts of trace metals in leafy vegetables.

Mujtaba Baqar, Nadia Jamil, Naveed Ahsan, Kiran Khanum, Abdul Qadir, Mariyam Zameer, Anam Khalid · Transylvanian Review · Pakistan (Lahore)

This case study investigated the impacts of heavy metals from wastewater irrigation on soil, groundwater, and leafy vegetables (Indian mustard, spinach, fodder) in the Charrar Drain catchment, Lahore, Pakistan. Samples were collected from seven sites. Drain water showed Cd, Cr, and Pb concentrations exceeding limits at most sites, and groundwater Cd concentrations also exceeded limits, though Cr and Pb were within permissible ranges. Soil samples contained Cd, Cr, and Pb, and leafy vegetables irrigated with wastewater showed varying heavy metal concentrations, indicating a heavy metal bioaccumulation issue that may exceed threshold limits.

Arti Bhatia, Shivdhar Singh, Amit Kumar · Water Environment Research · India (Delhi)

A study in Delhi, India, investigated heavy metal contamination (cadmium, lead, zinc, copper) in irrigation water, soil, and vegetables from four peri-urban and one wholesale site. Most samples from peri-urban areas exceeded safe limits for lead and cadmium. Vegetables from the wholesale market showed only higher lead concentrations. Among peri-urban vegetables, only okra exceeded the safe limit for cadmium, while several wholesale vegetables (potato, coriander, chilies, pea, carrot) exceeded the limit for lead regarding health risk.

Gauthier Dobigny, Madougou Garba, Caroline Tatard, Anne Loiseau, Maxime Galan, Ibrahima Kadaouré, Jean‐Pierre Rossi, Mathieu Picardeau, Eric Bertherat · PLoS neglected tropical diseases · Niger

An extensive survey of urban rodents in Niamey, Niger, investigated the presence and distribution of rodent-borne pathogenic Leptospira species. Leptospires were not detected in the core city, but L. kirschneri was found in Arvicanthis niloticus and Cricetomys gambianus, rodent species restricted to irrigated cultures within the city. This study indicates the importance of market gardening in the maintenance and circulation of leptospirosis within Sahelian cities.

Emmanuel Yennumi Wandaat, Joseph Xorse Kugbe · Asian Journal of Agriculture and Food Sciences · Ghana

A study on vegetable production in Ghana's Tano South District surveyed 132 urban farmers and 5 stakeholders. Farmers relied solely on chemical pesticides for pest control and lacked in-depth knowledge of Integrated Pest Management (IPM). Inappropriate handling and non-use of protective clothing led farmers to report health issues like dizziness, skin irritation, and nausea, while indiscriminate spraying resulted in pesticide residues posing serious health risks to consumers and the environment.

Nimoh Fred, Ohene-Yankyera Kwasi, Poku Kofi, Konradsen Flemming, Claude-François Robert · Journal of Development and Agricultural Economics · Ghana

A study in Ghana's Shai-Osudoku district investigated farmers' attitudes toward excreta reuse for peri-urban agriculture, surveying 400 randomly selected respondents. A majority of respondents disagreed that excreta are waste and were willing to use them as fertilizer. However, a majority also agreed that excreta can pose health risks, and perceptions on reuse differed among households.

Muhammad Zaman, Faqir Muhammad Anjum, Ali Asghar, Muhammad Sajid · · Pakistan

This study estimated organophosphate pesticide exposure from okra and brinjal consumption in urban populations of Punjab, Pakistan. 90 samples each of okra and brinjal were collected from peri-urban areas of Faisalabad, Multan, and Gujranwala and analyzed for chlorpyrifos, profenophos, and triazophos residues. Findings showed that 85 (47.22%) of the 180 samples were contaminated, and 15 (8.33%) samples had residue values higher than Maximum Residue Limits (MRLs).

Prem José Vazhacharickal, Sumita Gupta Gangopadhyay · Kobra (Universitätsbibliothek Kassel) · India

This paper examines urban and peri-urban agriculture (UPA) in India, focusing on wastewater irrigation and its associated human health risks. The study identifies potential health hazards for farmers, laborers, and consumers, including microbial pathogens and helminth (intestinal parasites). While UPA is presented as an option to address urban food demand, the paper emphasizes that "good practice UPA" requires integrated approaches and suitable risk reduction mechanisms to improve safety.

Pay Drechsel, Andrew Adam‐Bradford, Liqa Raschid-Sally, Drechsel, Pay, Adam-Bradford, A., Raschid-Sally, Liqa · AgEcon Search (University of Minnesota, USA) · Ghana

This chapter introduces urbanization in West Africa, particularly Ghana, the general role of urban agriculture, and the common use of polluted irrigation water. It focuses on irrigated smallholder vegetable production, reflecting on the key challenges, dynamics, and resilience of this farming system.

Joseph Agossou, Léonard Afouda, Julien Didier Adédémy, Alphonse Noudamadjo, Catherine N’da Tido, Emanliikpon Sylvain Ahohoui, Pierre G. Tovihoudji, Farouk Mazou, Benjami Fayomi, Simon Akpona, Sikiratou Adéothy-Koumakpaï, B Ayivi · Environnement Risques & Sante · Benin (Parakou)

This study analyzed the bacteriological and parasitic load in wastewater and market garden products from five major production sites in Parakou, Benin, where farmers use wastewater for irrigation. High concentrations of fecal coliforms, Escherichia coli, Salmonella enterica, Shigella spp., Entamoeba coli, Giardia intestinalis cysts, and helminth eggs were found in irrigation water, vegetables, and farmers' stools. The use of wastewater resulted in high contamination of vegetables, particularly cabbage, large lettuce, and carrot leaves, by fecal coliforms, Salmonella enterica, and Escherichia coli.

UM Dawaki, A. U. Dikko, SS Noma, U. Aliyu · Nigerian Journal of Basic and Applied Sciences · Nigeria

A study investigated the total, exchangeable, and soluble concentrations of heavy metals (Cu, Cr, Ni, Zn, Pb, Cd) in urban agricultural soils along three rivers (Challawa, Jakara, and Watari) in Kano, Nigeria. Cadmium concentrations at Jakara and Challawa exceeded maximum allowable concentrations in soils. Heavy metal concentrations were found to be significantly higher in areas irrigated with industrial and domestic sewage (Challawa and Jakara) compared to the control site (Watari).

A. N. Mutune, M. A. Makobe, Mary Abukutsa‐Onyango · African Journal of Environmental Science and Technology · Kenya (Nairobi)

This study analyzed heavy metal content in 10 common African leafy vegetables and their rhizosphere soils from 25 sites along Nairobi Rivers, Kenya. While soil metal concentrations were generally within WHO/FAO permissible levels, except for some cadmium instances, all metals except copper in vegetables exceeded recommended limits at a few sites. This indicates potential heavy metal absorption from industrial and domestic effluent.