Urban garden soils and vegetables as vectors of potentially toxic elements across Bratislava: Citywide distribution, sources, and health implications

Urban gardening offers multiple societal benefits, supporting both mental and physical well-being while enhancing access to fresh, locally grown produce. However, it may also pose potential health risks due to contamination of urban soils with potentially toxic elements (PTEs), including trace metal(loid)s. This study investigated metal(loid) concentrations in soils and homegrown vegetables from urban gardens across Bratislava (Slovak Republic) and evaluated the influential factors affecting their accumulation and bioavailability. Median copper (Cu) concentrations in vineyard soils (51 mg kg -1 ) were twice those in non-vineyard soils (25 mg kg -1 ). In contrast, raised-beds gardens exhibited significantly lower concentrations of most metal(loid)s compared to ground plots ( p <0.05). Soil concentrations of cadmium (Cd), Cu, lead (Pb), antimony (Sb), and zinc (Zn) showed a positive correlation with garden age and negative correlation with distance from the historical city core (pre-1946 boundary), suggesting legacy anthropogenic inputs. Integrated analyses, including enrichment factor calculations and statistical source apportionment, confirmed that Cd, Cu, Pb, Sb, and Zn in garden soils originated predominantly from anthropogenic sources; whereas, elements such as aluminum (Al), chromium (Cr), lithium (Li), nickel (Ni), and vanadium (V) were likely governed by natural geological processes, including variation in parent material composition. Concentrations of Cd, Ni, and Pb in edible vegetables remained below the maximum allowable limits set by European Union (EU) regulations. Estimated daily intakes of all metal(loid)s, based on average vegetable consumption, were substantially below respective tolerable daily intake thresholds. Human health assessments indicated negligible non-carcinogenic risks (hazard index < 1.0) and very low carcinogenic risk ( < 10 –4 ), suggesting minimal public health concerns associated with consumption of homegrown produce or incidental soil exposure in these gardens. This study represents a comprehensive, citywide assessment of trace element distribution in urban gardens within a medium-sized Central European city. It advances scientific understanding of metal(loid) dynamics in urban agroecosystems and supports evidence-based guidance to enhance public awareness of both the benefits and potential risks of urban agriculture in Bratislava. • First citywide assessment of metal(loid)s in urban gardens of a Central European city was performed. • Gardening practices and urban history shaped soil metal(loid) accumulation patterns. • Granitoid-derived soils showed natural enrichment in Al, Ba, Be, and Li. • Vegetable metal(loid) levels remained below EU safety limits citywide. • Overall findings revealed negligible health risks from soil and vegetable exposure to urban gardeners.