Research & reports

Jacek Antonkiewicz, Iwona Paśmionka, Grzegorz Szychowski · Soil Science Annual · Poland

Following a flood that inundated allotment gardens in Nysa, southern Poland, for up to 14 days after the water rose on 14 September 2024, researchers analyzed 12 soil samples collected in early spring 2025 from two allotment garden sites. Most soils were found limed and disinfected, with high organic matter but low total potassium, sodium and sulfur. Zinc and copper concentrations exceeded the average for Polish arable soils, pointing to use of materials enriched with these elements.

Sabina Rossini Oliva, Rafael López Núñez · Environmental Science and Pollution Research · Spain (Andalusia)

This study evaluated potentially toxic elements (PTEs) in vegetables and topsoils from urban gardens in Seville, Cordoba, Huelva, and a mining area (Riotinto), Spain, comparing them with market and peri-urban samples. Soils in the mining area and cities generally showed higher contamination with As, Cr, Cu, Pb, and Zn compared to other locations. Despite this, all PTE concentrations in vegetables from the studied urban gardens, including those from As-contaminated soils, were below health-based guidance values and market levels (except lettuce), and human health risk assessments indicated safe consumption.

Elliot Buckminster, Charlotte Breckenridge, Thomas Sedgwick · International Journal of Research in Agronomy · United Kingdom

This research quantified soil-to-plant transfer factors for six heavy metals (Cd, Pb, Zn, Cu, Ni, Cr) in lettuce, spinach, and carrot across 20 peri-urban agricultural sites in Berkshire, UK, from 2021-2022. Cadmium exhibited the highest mean transfer factor (0.31), and at 4 of 20 sites, cadmium concentrations in lettuce exceeded the EU maximum limit of 0.20 mg/kg fresh weight. Soil pH was a strong predictor for Cd and Zn transfer factors, with TFs increasing below pH 6.0.

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.

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.

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.

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).

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.

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.