Heavy metal contamination in soil and vegetables: a health risk assessment from urban areas of Sylhet, Bangladesh.

Rapid industrialization, urban expansion, and inadequate waste management in the peri-urban areas of Sylhet city, Bangladesh, have raised concerns regarding heavy metal accumulation in agricultural soils and vegetables and their potential implications for human health. However, information on heavy metal transfer from soil to edible crops and the associated health risks in this rapidly developing region remains limited. This study assessed heavy metal concentrations in peri-urban agricultural soils and commonly consumed vegetables and evaluated their potential human health risks. A total of 60 composite soil and vegetable samples were collected from 21 locations around Sylhet city during the Rabi season (January-March 2024). Concentrations of cadmium (Cd), lead (Pb), nickel (Ni), zinc (Zn), copper (Cu), chromium (Cr), iron (Fe), and manganese (Mn) were determined using inductively coupled plasma mass spectrometry (ICP-MS). In both soils and vegetables, Fe and Mn were the predominant metals, whereas Cd and Pb occurred at the lowest concentrations. Bioconcentration factor (BCF) values for Cd exceeded 1 at three locations (up to 5.8), indicating a potential risk of Cd accumulation in vegetables, while Cu exhibited a BCF greater than 1 at one location. Brinjal (Solanum melongena L.) showed the highest accumulation capacity among the investigated vegetables. Hazard index (HI) values ranged from 0.44 to 2.02, with seven sampling sites exceeding the safety threshold (HI > 1). The highest HI values were observed in cabbage (2.02), red amaranth (1.89), and tomato and gourd samples from specific locations, indicating potential non-carcinogenic health risks from long-term consumption. These results highlight a possible cumulative non-carcinogenic health risk for peri-urban consumers who depend on locally grown vegetables in Sylhet and emphasize the need for regular heavy metal monitoring and better soil management in this area.