Research & reports

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.

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.

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.

Mahantayya V Math, Yashoda R Kattimani, Manjusha M Padhye · Indian Journal of Community Medicine · India (Ahmadabad)

This study points out the impact of wastewater use in urban agriculture on the incidence of diarrhea in Ahmadabad, India. Vegetables grown with wastewater have an increased risk of internalization of food-borne bacteria such as E. coli and Salmonella into edible plant parts, posing a serious health risk. Contaminated water, soil, poor hand hygiene, and improper handling are sources of bacterial contamination for vegetables and fruits.

Alfan Prianggara, Gunanti Mahasri, Abdul Manan · Journal of Aquaculture and Fish Health · Indonesia (Surabaya)

A survey in Surabaya, Indonesia, investigated water quality and endoparasite prevalence in Nile tilapia (Oreochromis niloticus) from urban farming floating cage programs. Water quality parameters were measured, and average endoparasite prevalence was 5.71% for Eimeria spp. and 8% for Acanthogyrus spp. The study found positive correlations between water clarity, ammonia, and DO with Eimeria spp. prevalence, and between temperature, pH, nitrate, and nitrite with Acanthogyrus spp. prevalence, indicating a link between water quality and parasite infection.

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.

Timo Falkenberg, Deepak Saxena · Indian Journal of Community Medicine · India (Ahmedabad)

A 12-month case-cohort study of 187 households in four communities of Ahmedabad, India, purposively selected by irrigation water type (groundwater, surface water, wastewater), with bimonthly self-reported health diaries and most-probable-number measurement of Escherichia coli in water. Mean E. coli concentrations per 100 mL were 3.04×10^4 (groundwater), 9.28×10^5 (surface water) and 4.02×10^9 (wastewater) — all exceeding international irrigation water standards. Diarrhoea incidence was 7.92 episodes per 1000 person-weeks in the groundwater area versus 13.1 (wastewater) and 13.4 (surface water), with a positive correlation between irrigation water quality and diarrhoea. Wastewater reuse is often promoted as a water-scarcity fix for urban agriculture; this study shows it carries a health cost borne by the farming households themselves.

Timo Falkenberg, Deepak Saxena, Thomas Kistemann · The Science of The Total Environment · India (Ahmedabad)

A cohort study investigated the contribution of wastewater irrigation to in-household water contamination among urban farming households in Ahmedabad, India, within the context of WASH (Water, Sanitation, Hygiene). Drinking water samples from 204 households were collected four times over 12 months, and E. coli was quantified. Significant positive differences in water quality between point-of-source and point-of-use samples were identified in 78% of households. During the monsoon, the peak of contamination, only 6% of households had access to safe drinking water at the point-of-use. Wastewater irrigation showed an adverse effect on in-household water contamination, with an effect size larger than the mitigation effect of access to sanitation or personal hygiene.

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.

Mayrina Firdayati, Peni Astrini Notodarmojo, Barti Setiani Muntalif, Didit Trihartomo, Inat Shani Fathuna, Kiki Somantri · INDONESIAN JOURNAL OF URBAN AND ENVIRONMENTAL TECHNOLOGY · Indonesia

Against a background of high helminth-infection prevalence in Indonesia — which led the government to issue a 2017 ministerial regulation on preventing soil-transmitted helminths (STH) — this study investigated the potential presence of helminth eggs capable of causing STH infection in two urban agricultural areas in the northern and southern parts of Bandung City. Samples of inlet and plantation-area water, soil, and harvested water spinach from both areas were analyzed for helminth eggs using a modified Bailinger method, and egg counts of 1–119 eggs/L were found across the water, soil, and vegetable samples. The results confirmed that irrigation water in both areas was contaminated with feces, with average fecal coliform counts exceeding the allowable value for irrigation water under Indonesia's Grade 4 water-quality criteria; variation in egg counts was attributed to environmental conditions such as temperature, humidity, and soil type. Helminth-egg levels in the irrigation water and land samples exceeded the values recommended by the WHO's 2006 guidelines for safe use of wastewater in agriculture, which the study links to an increased risk of helminth infection among consumers, agricultural workers, and residents near the farmland.

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.

Jennifer C. Latimer, David Van Halen, James H. Speer‬, Stephanie Krull, Patricia G. Weaver, Joseph M. Pettit, Heather Foxx · PubMed · United States (Indiana)

This study collected over 1,061 surface soil samples from an approximately 1.25-acre urban community garden in Terre Haute, Indiana, during the summer of 2012, to evaluate the spatial distribution of lead at the plot level. The results highlighted significant variability in lead concentrations within small areas of a former residential property, with some areas showing high lead concentrations (600 ppm). Based on these findings, several areas of concern were identified, and the community garden was reconfigured to reduce potential lead exposure to gardeners and the local community.

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.

M.P Dr. Enny Zulaika · · Indonesia

A study using Azotobacter isolated from eco urban farming land at ITS, Indonesia, tested resistance and bioaccumulation of mercury (HgCl2) via selective media isolation, streak resistance testing and atomic absorption measurement, analyzed by ANOVA and LSD at the 5% level. Three isolates (A5, A6, A9) tolerated HgCl2 up to 20 mg/L, and at 5 mg/L exposure the highest bioaccumulation efficiency was recorded for A5 (89%) and A9 (87%).

Anjar Lulu Sakinah · · Indonesia

Mercury is a highly toxic and hazardous heavy metal, and bacteria able to live in mercury-contaminated habitats — mercury-resistant bacteria, including Azotobacter — are known to exist. This study aimed to obtain superior Azotobacter isolates resistant to mercuric chloride (HgCl2) from land at the ITS (Institut Teknologi Sepuluh Nopember) Eco Urban Farming site — land where mercury contamination was present — and to determine mercury reductase enzyme activity as a bioreductant converting Hg2+ to Hg0. Isolation used selective Azotobacter agar media, resistance was tested by a slant-agar streak method containing HgCl2, and mercury reductase activity was analyzed using the MRA method and spectrophotometry at 340 nm. Ten HgCl2-resistant Azotobacter isolates were obtained; isolates A5 and A9 tolerated 10 mg/L HgCl2 with optimal growth and relatively high mercury reductase activity, showing a reduction capacity of ≥3 mg/L and a reduction efficiency above 70% at an HgCl2 concentration of 5 mg/L.

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.

Jingjing Zhang, Jingshuang Liu, Rui Yu, Qiang Liu, Yang Wang · Human and Ecological Risk Assessment An International Journal · China (Jilin City)

This study analyzed 50 surface soil samples from urban vegetable fields in Jilin City, China, for thirteen organochlorine pesticides (OCPs). Based on soil quality standards, DDTs and chlordanes were categorized as light pollution, while HCHs showed no pollution for most samples. The study concluded that despite the presence of various OCPs residues, the soils are still safe and suitable for agricultural production.

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.

Jin‐Won Kim, In‐Wook Choi, Won-Seok Na, Enkhjargar Baljii, Yong-Man Yu, Young Nam Youn, Young‐Ha Lee · Journal of Food Hygiene and Safety · South Korea (Seoul)

From September to October 2012, 530 samples of nine vegetable types were collected from 11 urban community gardens in Seoul to assess their microbiological quality. Mean total aerobic bacteria and coliforms were detected at 6.3 log CFU/g and 4.3 log CFU/g, respectively, with coliforms found in 67% of samples and E. coli in 2.3%. While foodborne pathogens were not detected, the presence of coliforms and E. coli indicates room for improvement in microbiological safety.

Qiang Liu, Jingshuang Liu, Qicun Wang, Yang Wang · Human and Ecological Risk Assessment An International Journal · China (Jilin City)

This study investigated heavy metal pollution levels by collecting 50 soil samples from urban vegetable fields in Jilin City, China. Mean contents of Pb, Cr, Cu, Ni, Zn, and Cd were higher than their corresponding natural background values. However, the distribution of comprehensive pollution index values indicated that concentrations of these heavy metals in most agricultural fields did not exceed baseline values affecting agricultural production safety and human health according to China's soil environmental quality standard, concluding insignificant contamination by these metals in Jilin City.

Anjar Lulu Sakinah, Enny Zulaika · Jurnal Sains dan Seni ITS · Indonesia

This study aimed to isolate Azotobacter strains from the Eco Urban Farming ITS land in Indonesia that are resistant to HgCl2 and potentially produce mercury reductase enzymes. Ten HgCl2-resistant Azotobacter isolates were obtained, with isolates A5, A6, and A9 showing the highest resistance at 20 mg/L HgCl2. Isolates A5 and A9 were identified as having the potential to produce mercury reductase enzymes.

Kim Jin-Won, Yong-Man Yu, Na Won-Seok, Baljii Enkhjargar, Choi In-Wook, Youn Young-Nam, Young-Ha Lee Young-Ha · Horticultural Science and Technology · South Korea

In Seoul, South Korea, 260 samples of Chinese cabbage and lettuce were collected from four urban community gardens and six roof gardens between September and October 2012 and assessed quantitatively and qualitatively for microbiological and parasitological contamination. Mean total aerobic bacteria counts were 6.1±0.8 log CFU/g (range 5.4±0.6-7.1±0.8) and mean coliform counts were 4.0±0.7 log CFU/g (range 2.3±0.6-6.1±0.9), with coliforms detected in 59.6% of the 260 samples. There was no significant difference in contamination levels between cabbage and lettuce, but produce from community gardens showed higher levels than that from roof gardens (p>0.05). E. coli was isolated from 3.1% of vegetables at a level of 1.5±0.2 log CFU/g. Among foodborne pathogens, Staphylococcus aureus was detected in 1.5% of samples, while Salmonella spp., Listeria monocytogenes and E. coli O157:H7 were not detected in any sample. Unidentified parasite eggs were also found in two cabbage samples (0.8% of the total). The results indicate bacteriological contamination is present in produce grown through urban farming in Seoul, and the study calls for efforts to reduce biological contamination during cultivation.

Prem José Vazhacharickal, Martina Předotová, D. Chandrasekharam, Sharit K. Bhowmik, Buerkert, Andreas · Journal of Agriculture and Rural Development in the Tropics and Subtropics (University of Kassel) · India (Mumbai)

A study surveyed 38 railway gardeners to characterize urban and peri-urban agricultural production along railway tracks in the Mumbai Metropolitan Region. Irrigation water contained nutrients but also heavy metals such as lead, cadmium, and mercury, and pathogens like Escherichia coli. Heavy metal levels exceeded critical thresholds in surface soils for chromium, nickel, and strontium, and in produce for lead, cadmium, and strontium.

K.G. Rosin, Ravinder Kaur, Sushma Singh, Prabhat Kumar Singh, Digvijay Dubey · Procedia Environmental Sciences · India

A study was conducted in peri-urban agricultural sites around Faridabad, Haryana, India, to assess groundwater contamination and the contribution of salt/trace metal-laden irrigation waters. Mean EC, Cl, and F concentrations in root zone leachates were found to be far beyond permissible limits, and some trace metals posed a threat to deep percolating waters. However, due to existing cropping patterns and deeper water table depths, the groundwaters were not yet vulnerable to these salts/trace metals, and the presence of salts in the groundwaters was primarily geogenic.