Accumulation of arsenic and other metals in soil and human consumable foods of Meherpur district, southwestern Bangladesh, and associated health risk assessment

Abstract

Groundwater and soil contaminated with arsenic (As) are significant environmental health concerns worldwide and have become a serious health issue for millions of Bangladeshis. This contaminated groundwater is commonly used for Boro rice production during the dry season in Bangladesh, leading to long-term As deposition in soils. The consequences of long-term irrigation with As-contaminated groundwater for bioaccumulation in food crops and hence dietary exposure to As and other metals are a threat to the resident. Highly arsenic (292 µg L⁻¹) contaminated groundwater used to irrigate in the study area increases the As content (mean: 24.5 mg kg⁻¹) in irrigated soil than non-irrigated soil (mean: 8.43 mg kg⁻¹). The high enrichment factor (mean: 16.8) and geo-accumulation index (mean: 2.33) revealed that the soil of that particular area is strongly contaminated by As. In paddy, roots showed the maximum As concentration (mean: 139.8 mg kg⁻¹) followed by straws (mean: 5.25 mg kg⁻¹) and grains (mean: 1.23 mg kg⁻¹) where 85–95% As exist in the roots of paddy, and only 0.8–1% As translocate to the harvesting part of the rice in the study area. In food samples, two rice grains (R-1, R-3) and a drumstick (FS-5) exceed the Indian standard of As concentration (As: 1.1 mg kg⁻¹) in food. According to World Health Organization, the metals concentrations in all food samples exceeded the permissible limit except for Cu and Pb in red amaranth; Cr, Cd, and Pb in guava; and Cu and Cd in drumsticks. Higher values of bioaccumulation factor (BAF: 2.94) and the net translocation coefficient (NTC: 6.17) indicate As-accumulation in food from adjacent contaminated soil. Daily metal intake from food consumption suggests that the heavy metal(loid)s like As, Ni, and Pb represent high concentrations and exceed the daily ingestion limits (As: 3 µg kg⁻¹ day⁻¹, Ni: 1.3 µg kg⁻¹ day⁻¹, and Pb: 3.57 µg kg⁻¹ day⁻¹) developed by the Food and Agriculture Organization and European Food Safety Authority. Carcinogenic (> 10^–6) and non-carcinogenic (HQ > 1) health risks of As, Pb, Cd, and Cu suggest that the community was at potential health risk according to the United States Environmental Protection Agency.