Abstract

Intensive vegetable production can increase the transfer of persistent toxic trace elements from agricultural soils into the food chain, particularly where agrochemical use, irrigation inputs, and local geochemical conditions are insufficiently characterized. This study was undertaken to assess toxic trace-metal contamination levels in soils and vegetables from two renowned vegetable-producing subdistricts—Shibganj and Kahaloo—in the Bogra district, Bangladesh. The study also estimated potential human health risks by evaluating the dietary intake of these elements. It measured Pb, Ni, Cd, and Cr content in six vegetables and their respective farm soils using an atomic absorption spectrophotometer (AAS). The average concentrations of Pb, Ni, Cd, and Cr in farm soils of Shibganj and Kahaloo subdistricts were 158.3 ± 8.83, 31.5 ± 5.25, 0.43 ± 0.08, and 14.1 ± 2.16 µg g−1 and 164.1 ± 4.60, 35.7 ± 6.91, 0.53 ± 0.14, and 9.37 ± 2.87 µg g−1, respectively. Soils collected from all locations in both subdistricts of Bogra fall under ‘moderate’ ecological risk. Regarding the pollution load index (PLI), 66.7% of Shibganj and 75.0% of Kahaloo sampling sites had a PLI > 1.0, confirming that ‘metal pollution exists.’ Based on the calculated bioconcentration factors (BCFs), Cr and Cd show a high tendency to migrate from soil to various vegetables in the study area, though the mean Cd BCF for brinjal in Shibganj exceeded 1.0 due to a single high observation. The results demonstrated that the edible parts of potatoes, onions, and chilies accumulate significant amounts of toxic trace elements. The calculated mean daily intake of Pb and Cr in all vegetables ranged from 0.33 to 1.21 mg person−1 day−1 and from 0.10 to 0.64 mg person−1 day−1, respectively, exceeding the upper tolerable intake limits. Similarly, dietary intake of potatoes showed both non-carcinogenic and carcinogenic risks, while brinjal showed only carcinogenic risks for adults. Redundancy analysis (RDA) indicates that the measured soil parameters are strong predictors of the response variables (trace element content in various vegetables). Overall, the results identified Pb-dominated soil contamination and human exposure to Pb and Cr associated with vegetables as the principal concerns. To address these issues, priority actions should be given to source apportionment and testing of various agricultural inputs. Additionally, before implementing site-specific remediation or issuing consumption advisories, these risks should be validated through metal speciation and bioaccessibility analyses.

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