Research & reports

Karina Corada, Caroline Nash, Prashant Kumar, Stuart Connop, Laura Wendling · Nature-Based Solutions · Global

A synthesis paper on the largely unexplored role of domestic gardens in influencing local air quality. While gardens are widely recognized for cultural and health benefits, particularly mental well-being and everyday contact with nature, the paper states few studies have examined air quality dynamics within residential garden settings. It notes that general urban green infrastructure research suggests vegetation structure, plant traits, and spatial configuration shape pollutant capture, but these findings have not been tested in domestic gardens, where microclimates and spatial constraints differ markedly. Evidence from food-growing gardens and allotments further suggests edible crops cultivated near roads may accumulate airborne pollutants, particularly metals, underscoring the need for research on exposure pathways and allotment locations. The paper identifies a significant gap in current green infrastructure and air-pollution research: the lack of empirical evidence on how domestic gardens function as socio-ecological systems with implications for air-quality regulation.

Hoque MN, Rana ML, Gilman MAA, Pramanik PK, Islam MS, Punom SA, Rahman R, Hassan J, Rahman MS, Ramasamy S, Schreinemachers P, Oliva R, Rahman MT · Environmental Monitoring and Assessment · バングラデシュ・ダッカ／ガジプール

A shotgun metagenomic study motivated by how little is known about the microbial communities and antimicrobial resistance (AMR) profiles of rooftop and surface garden soils in Bangladesh, and their potential role as reservoirs and disseminators of AMR, despite the growing expansion of urban agriculture. Twenty-seven soil samples were sequenced — 7 from Dhaka rooftop gardens, 6 from Dhaka surface gardens, 8 from Gazipur rooftop gardens and 6 from Gazipur surface gardens. The work identified 88 antibiotic resistance genes (ARGs), of which 19 (21.6%) were shared across all sites, and found significant differences in resistome composition by garden type (p = 0.04). Rooftop soils harboured more ARGs (Dhaka 50, Gazipur 48) than surface soils (Dhaka 40, Gazipur 41) and were dominated by glycopeptide resistance genes, collectively 62.43-74.07% of ARGs; rooftop soils were also enriched in efflux pumps (adeF, 45.21% of rooftop ARGs) and the ribosomal-protection oxazolidinone resistance gene O23S (62.13% in Gazipur rooftops). Surface soils instead featured more genes mediating antibiotic inactivation, such as CATA (11.64% in Dhaka surface gardens) and fosBx1 (5.94% of surface ARGs).

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.

Anjoulie Brandner, Karolina Taczanowska, Brenda Maria Zoderer, Christoph Schunko · Urban forestry & urban greening · Austria (Vienna)

A survey of 458 respondents in Vienna, Austria, analyzed urban wild food foraging locations and preferences for urban green spaces (UGS). 1239 foraging locations were identified across 9 UGS types, with forest and meadow landscapes, parks, and UGS mosaics being most utilized. Foragers' major concerns were contamination from traffic and dogs.

Roberta Bulgari, Erdona Demiraj, Calogero Schillaci, Ahlem Tlili, Yushu Xia · Urban Agriculture & Regional Food Systems · Global

This special issue examines urban and peri-urban soil and plant management, highlighting that soil-related factors in urban agricultural systems pose unique challenges. Issues such as soil fertility, soil biodiversity, and soil contamination require further investigation to enhance urban agriculture's contribution to livability. The issue collects studies supporting sustainable soil management and crop diversification, and explores remote sensing and deep learning for soil health monitoring and plant disease detection related to contamination.

Bethaney Turner · · Global

This chapter explored human-soil relations in urban home and community gardens through ethnographic fieldwork. While biodiverse soil offers direct health benefits, the presence of contaminated, toxic soils, prevalent in lower socio-economic neighborhoods, was shown to expose inequities in access to safe gardening sites and hinder the realization of potential therapeutic benefits. It argues that the therapeutic benefits of gardens are best realized when humans cultivate attentive relationships with myriad multispecies companions.

Aikaterini N. Martini, Μ. Papafotiou, Ioannis Massas, Nikoleta Chorianopoulou · Plants · Greece

Origanum dictamnus, a perennial herb endemic to Crete, Greece, was grown at two cultivation sites in Athens — an extensive green roof and ground level next to a moderate-traffic road — in two substrate types at 10 cm depth, to examine growth along with nutrient content (N, P, K, Na) and heavy metal accumulation (Cu, Pb, Ni, Mn, Zn, Fe) in its tissues. Plant growth was favored by the soil substrate but was also satisfactory in the soilless substrate. Cultivation site affected heavy metal accumulation, with higher concentrations found in leaves and flowers at street level, though no differences appeared in roots. Washing reduced heavy metal concentrations only in leaves grown at street level. Substrate type significantly affected manganese concentration in all tissues and iron concentration in roots, with the highest values in the soil substrate. The species could be cultivated on sustainable green roofs, preferably on a soilless substrate to reduce structural weight, but careful selection of the cultivation site was identified as necessary to minimize contamination with environmental pollutants when human consumption is intended.

Anna Barra Caracciolo, Valentina Terenzi · Microorganisms · Global

A review of the rhizosphere as a microhabitat of intense chemical dialogue between plants and microorganisms covers synergistic interactions that can enhance plant function and productivity, including responses to stress conditions such as heavy metal (HM) contamination, alongside the risks such contamination poses. Where heavy metals are present in agricultural soils, there is a risk of metal uptake by edible plants leading to bioaccumulation in humans and animals with detrimental health consequences, and plant productivity itself can be negatively affected; many bacteria have defensive mechanisms for resisting heavy metals and can improve plant responses to HM stress, but achieving such beneficial rhizosphere interactions is described as hard to attain in agroecosystems managed with traditional practices that focus on maximizing crop yield.

Olga Romanova, Sarah Taylor Lovell · Urban Agriculture & Regional Food Systems · Global

This review assesses the capacity of woody species (trees and shrubs) used in urban food forests to accumulate polycyclic aromatic hydrocarbons (PAHs), heavy metals (HMs), and metalloids, given limited existing literature on food-safety risk in urban fruit- and nut-producing trees compared with annual crops. General trends identified were (a) lower risk of HM and PAH accumulation in woody species than in vegetables, and (b) less accumulation in the fruit of woody species than in other parts of the same species. However, these trends are not always consistent, and accumulation depends on factors such as the concentration of a given contaminant in the environment, contaminant type, and species or variety. The review states there is a critical need for more research on the safety of growing edible fruits and nuts on trees and shrubs in contaminated urban environments.

Maëlle Tripon, Dorothée Boccanfuso, Marie-Ève Yergeau · Cahiers de recherche · Global

This literature review examines urban agriculture (UA) models, their implementation contexts, production needs, and impacts. It highlights that UA faces limitations, particularly restricted access to good quality (unpolluted) soil, water, and air, which can negatively impact productivity. UA can also have negative impacts on ecosystems and human health, such as pollution and diseases, depending on management methods.