Toxic trace element (TTE) contamination in urban soils may pose potential health risks, especially in cities with previous industrial activities. This study aimed to investigate soil contamination in urban allotments in Sheffield, the uptake of TTEs in autumn and spring sown onions (Allium cepa), and their potential risks on human health via consumption of the crops. Paired soil and plant samples were taken in triplicates from four private allotments to assess potentially elevated levels of lead (Pb), zinc (Zn), copper (Cu), arsenic (As), and chromium (Cr). These elements in soils exceeded the ambient background levels for England. Both Pb and As exceeded some UK and EU soil tolerable limits. Concentration factors (CF) were calculated as the ratio of trace element in the plant as compared to that in the soil, and uptake rates were in the order Zn>Cu>Cr>Pb>As. Concentrations were higher for most TTEs in spring sown onions (SSO), and had significantly higher CF (p < 0.05) for Pb and Cr than autumn sown onions (ASO), whereas the opposite was true for As. Toxic elements in plants did not exceed FAO/WHO intake limits when considering TTE content per plant and consumption rates. Human health risk assessment calculations using target hazard quotients (THQ) and hazard indexes (HI) indicated that consuming onions alone did not pose an immediate health risk.

城市土壤中的有毒微量元素（TTE）污染可能构成潜在的健康风险，尤其是在进行过工业活动的城市中。这项研究旨在调查谢菲尔德市区的土壤污染情况，秋季和春季播种洋葱对TTE的吸收情况（葱属洋葱），以及通过食用农作物对人类健康的潜在风险。成对的土壤和植物样品一式三份，来自四个私人配地，以评估铅（Pb），锌（Zn），铜（Cu），砷（As）和铬（Cr）潜在升高的水平。土壤中的这些元素超过了英格兰的环境本底水平。铅和砷均超过了英国和欧盟的土壤容许极限。以植物中的微量元素与土壤中的微量元素的比例来计算浓度因子（CF），其吸收速率为Zn> Cu> Cr> Pb> As。春季播种洋葱（SSO）中大多数TTE的浓度较高，而CF（p 与秋季播种洋葱（ASO）相比，铅和铬的含量<0.05），而砷的情况则相反。考虑到每棵植物的TTE含量和消费率时，植物中的有毒元素没有超过FAO / WHO的摄入限量。使用目标危害商（THQ）和危害指数（HI）进行的人类健康风险评估计算表明，仅食用洋葱并不会立即造成健康风险。