Research & reports

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.

Cécile Le Guern, Liliane Jean‐Soro, Béatrice Bechet, Thierry Lebeau, Dorine Bouquet · Land Degradation and Development · France

Urban allotment gardens in Nantes, France, were found to have soil contamination, with lead (Pb) levels ranging from 100–400 mg kg−1, posing health risks. Local actors collaborated to characterize soil, evaluate sanitary risks, and discuss management options. The most frequent solution was replacing polluted soils with clean soils, while other strategies included on-site management of excavated soil, non-accumulative cropping, or changing land use.

John Misenheimer, Clay Nelson, Evelyn Huertas, Myriam Medina-Vera, Alex Prevatte, Karen D. Bradham · Geosciences · Puerto Rico

Total and bioaccessible arsenic (As) and lead (Pb) levels, and their uptake by 10 commonly grown garden plants, were examined in three urban community gardens in Puerto Rico. Total As ranged from 2 to 55 mg/kg and Pb from 19 to 172 mg/kg in soils. Leaves accumulated higher concentrations of As and Pb than edible flesh, with culantro leaves showing the highest concentrations (3.2 mg/kg dw As, 8.9 mg/kg dw Pb).

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.

이윤숙 · · Global

Urban agriculture has gained emphasis due to its importance for leisure and recreation in modern society. However, public health may not be guaranteed due to continuous odors from animal compost. Biochar is an amendment that can reduce odors and enhance crop productivity, but this abstract is truncated and does not present specific research findings.

Eileen Bogweh Nchanji, Imogen Bellwood‐Howard, Nikolaus Schareika, Takemore Chagomoka, Johannes Schlesinger, D. Rodríguez Torres Axel, Glaser Rüdiger · International Journal of Agricultural Sustainability · Ghana (Tamale)

An ethnographic study in Tamale, Northern Ghana, assessed the sustainability of urban vegetable production between 2008 and 2014. While urbanization increased cultivation of profitable vegetables like cabbage, the practice involved irrigation with grey and wastewater and high pesticide use, posing health and environmental hazards. Industrial growth reduced open space urban agriculture by 8.7%, leading farmers to use interstitial spaces and peri-urban fringes, indicating a dynamic but not yet sustainable production system.

Marta Bożym · Ochrona Środowiska i Zasobów Naturalnych · Poland

A study measuring heavy-metal content (cadmium, lead, copper, zinc, nickel, chromium) in compost and resident earthworms sampled from home composters and allotment gardens in the Opole region of Poland. The compost samples themselves were not contaminated with heavy metals and stayed within Polish legal limits for solid organic fertilizers. However, metal accumulation in earthworms varied by metal: the bioaccumulation factor (BAF) was high for cadmium, lead and zinc, while no accumulation was found for nickel, chromium or copper. The authors conclude that earthworm species native to Poland, such as Eisenia fetida, can serve as potential bioindicators of metals in the environment.

Elizabeth A. Miernicki · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign) · United States

A study from the University of Illinois at Urbana-Champaign, USA, that identifies soil contamination as a universal concern in urban agriculture and notes that the long-term benefits of alternative soil management systems such as raised beds have not been explored in the scientific literature. Its stated objective is to determine the effects of six soil management options - direct soil with synthetic fertilizer (DSF), direct soil with organic amendments (DSO), raised-bed mixture with synthetic fertilizer (RBMF), raised-bed mixture with organic amendments (RBMO), raised-bed compost-only with synthetic fertilizer (RBCF), and raised-bed compost-only with organic amendments (RBCO) - on yield of kale, garlic, pepper, cilantro and radish, on soil biological, chemical and physical properties, and on ecosystem services such as water and nutrient retention. Data collected include marketable versus cull yield, soil nutrients and organic matter, soil moisture, weed emergence, infiltration rate and bulk density, but this abstract does not report the comparative results themselves.

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.

Hardiyanto Hardiyanto, Constancio C. de Guzman · Indonesian Journal of Agricultural Science · Philippines (Metro Manila)

This study investigated the levels and distribution of lead (Pb) and cadmium (Cd) in white cabbage, soil, and irrigation water from urban agricultural sites in Las Piñas and Parañaque, Metro Manila, Philippines. Field areas were divided into three sections based on distance from the main road (0, 25, and 50 m), and metal contents were measured by Atomic Absorption Spectrophotometry. The average Pb content (1.09 µg g-1 dry weight) in white cabbage was highest immediately beside the main road, with a similar trend in soil. A negative relationship was found between distance from the main road and Pb and Cd contents in white cabbage and soil. While overall concentrations of Pb and Cd in white cabbage, soil, and irrigation water were within acceptable limits, further study on heavy metal contamination in crops, especially those grown along main roads, was suggested.

Kafeel Ahmad, Zafar Iqbal Khan, Asma Ashfaq, Ameer Khan, Hazoor Ahmad Shad, Mujahid Sher, Zahoor-ul-Hassan Dogar, Ijaz Rasool Noorka, Sumaira Yasmin, Vincenzo Tufarelli, Eugenio Cazzato · The Philippine Agricultural Scientist · Pakistan

This study analyzed heavy metal and metalloid levels in soil and cabbage (Brassica oleracea) from two urban farming sites in Sargodha, Pakistan, irrigated with wastewater. Findings showed that mean concentrations of arsenic (As) and cadmium (Cd) in soil, and manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), cadmium (Cd), and lead (Pb) in cabbage, exceeded permissible limits at both sites. Significant differences were observed in metal and metalloid levels in vegetable samples between sites.

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.

Andrew Hursthouse, T. E. Leitão, Annette Voigt, Avigail Heller, Béatrice Bechet, Paulo Brito da Luz · HAL (Le Centre pour la Communication Scientifique Directe) · Europe

This chapter overviews factors influencing the chemical, physical, and biological status of soils, water, and the biosphere in urban allotment gardens. It highlights that urban garden soils, water, and biosphere are affected by pollution due to their location in city centers or suburbs, with traffic infrastructure and industrial zones widely identified as impacting soil and water quality. Concerns over long-term risks from pollutant transfer (mainly metals) from soil to plants in these uncontrolled environments have been widely publicized.

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.

M. G. Dahiru, Onaiwu Idahosa Enabulele · · Nigeria (Kano)

Microbiological and physicochemical parameters of urban wastewater from the Jakara Canal in Kano were analyzed to assess its potential for irrigation. Mean fecal coliform counts ranged from 64.43 ± 63.20 MPN 100/ml to 216.85 ± 350.16 MPN 100/ml, increasing along the canal. All physicochemical parameters were within FEPA and WHO/FAO acceptable limits, but conductivity needed monitoring to avoid salinity.

Vide Adedayo · Journal of Research in National Development · Nigeria (Lagos)

This study investigated poultry waste management in urban vegetable farms in Metropolitan Lagos from an ecosystem to human health perspective. Using a transdisciplinary approach, community participation, and socio-cultural, physiochemical, microbiological, and clinical information, the research revealed negative impacts and health problems associated with poultry waste management due to poor storage, composting, and packaging techniques. Consequently, adverse effects on users were identified.

B.M. Mercado-Borrayo, Silke Cram Heydrich, Irma Rosas‐Pérez, Manuel Hernández Quiroz, Claudia Ponce De León Hill · International Journal of Phytoremediation · Mexico

In a natural wetland in the Mexico City Metropolitan Area — a major supplier of crops and flowers whose canals hold high concentrations of organochlorine (OC) and organophosphorus (OP) pesticides — bioaccumulation of these pesticides was studied in water hyacinth (Eichhornia crassipes), a plant considered a plague but suggested in the literature to have phytoremediation potential. In vivo bioaccumulation differences for OC pesticides were largely explained by their log Kow, while all OP pesticides showed bioaccumulation regardless of log Kow, and the higher bioaccumulation factors of some accumulated OC pesticides could not be explained by log Kow alone, suggesting passive transport into the plant. Translocation ratios showed water hyacinth to be an accumulating plant with phytoremediation potential for all the organophosphorus pesticides studied and some organochlorine pesticides, and an equation for free water surface wetlands with floating macrophytes showed pesticide removal by the wetland with room for improvement through better management.

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.

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.

Aubin Ondo, Pascale Prudent, C. Massiani, Menye Biyogo, Mariane Domeizel, Jacques Rabier, François Eba · Journal of the Serbian Chemical Society · Gabon (Libreville)

An assessment of urban agriculture's impact on soil properties and metal uptake by leafy vegetables in Libreville, Gabon, found strong soil acidification and decreased nutrient/metal concentrations due to agricultural practices. Metal transfer to plants was significant, with amaranth accumulating more metals than other vegetables, though cadmium and lead were not detectable in plant tissues. Amaranth and roselle preferentially concentrated metals in their leaves.

Evaristo Mwaba Kapungwe · Indonesian Journal of Biotechnology (Universitas Gadjah Mada) · Zambia

This study investigated farming practices related to heavy metal contaminated wastewater irrigated farming in two peri-urban areas of Zambia: New Farm in Mufulira and Chilumba Gardens in Kafue. Data was collected by observing crop cultivation activities at field plots along transects in stratified land zones. The results revealed that farming practices were characterized by traditional land management and multiple cropping systems, influenced by agro-ecological factors and the availability of heavy metal contaminated wastewater, which has the potential to contaminate soils and crops.

Josh Beniston · The Knowledge Bank (The Ohio State University) · United States (Ohio)

An experiment on assessing and managing soil quality for urban agriculture was conducted during the 2011 and 2012 growing seasons on demolished vacant urban lots in Youngstown, Ohio. Soil compaction was identified as a primary constraint, with high bulk density values of 1.79 g cm⁻³ for in-ground plots and 1.55 g cm⁻³ for raised beds. Crop yield data from 2011 showed that both compost-amended and compost + biochar-amended plots had significantly greater crop yields than control plots, with compost + biochar plots achieving the highest harvest index values.

Y. Niang, S. Niang, Saliou Niassy, Y Dieng, Mohamed Gaye, K. Diarra · International Journal of Biological and Chemical Sciences · Senegal

This study assessed the effect of wastewater on the agronomical performance and hygienic quality of tomato and lettuce in Senegal, comparing it to tap water, irrigation modes, and fertilizers. While tomato showed no pathogenic germs with wastewater, lettuce watered with wastewater via aspersion contained significantly more pathogenic germs than those watered in draining mode. Significant differences in yield and fruit size were observed between lettuce treated with tap water and wastewater.

Sebastian U. Ugbaje, John O. Agbenin · International Journal of Environmental Studies · Nigeria

A pot experiment in Zaria, northern Nigeria, evaluated the chemical forms and phytoavailability of Cr, Ni, and Pb in savannah soil amended with two urban wastes and planted with sorghum. While urban waste application increased total metal concentrations in the soil, only Pb uptake by sorghum increased, with no corresponding increases for Cr and Ni. A single application of urban wastes significantly increased Pb uptake by sorghum, raising concerns about the long-term consequences of such applications in urban and peri-urban agriculture, especially regarding children's exposure to Pb.