Environ Monit Assess. 2026 Mar 31;198(4):387. doi: 10.1007/s10661-026-15239-8.
ABSTRACT
Heavy metal contamination in soils represents a critical environmental and public health challenge, particularly in intensively cultivated regions such as the Indo-Gangetic Plains. Despite widespread groundwater contamination studies in the region, systematic investigations of heavy metals in soils and associated ecological and human health risks remain limited. In this study, topsoil samples from 121 locations in Ballia district were analyzed for heavy metals, including Cr, Ni, As, Cd, Hg, and Pb. Contamination indices were used to assess soil contamination levels, while the Risk Index (RI) was applied to evaluate potential ecological risk. Human health risks were assessed using USEPA guidelines, and multivariate statistical techniques (PCA and HCA) were employed to identify dominant geochemical and anthropogenic signatures. Mean concentrations of Cr (138.7 mg/kg), Ni (52.5 mg/kg), and Hg (2.33 mg/kg) exceeded global background levels, with 70% of soils exceeding Indian agricultural screening values for Cr and nearly 46% for Ni. High enrichment of mercury (EF ≈ 143) was the principal contributor to ecological risk, with a mean RI of 1364, placing 72% of soils in the very high risk category. Human health risk assessment indicated that Ni (Incremental Lifetime Cancer Risk, ILCR = 1.27 × 10-4) and Cr (ILCR = 9.91 × 10-5) were the major contributors, accounting for ~ 95% of the total carcinogenic risk, with a cumulative ILCR of 2.26 × 10-4 exceeding the USEPA acceptable limits. Multivariate analysis suggests mixed sources, dominated by geogenic sorption and redox cycling processes, along with anthropogenic enrichment of Hg and Cd. These findings highlight the presence of multi-metal contamination in agricultural soils, and their potential leaching into groundwater may pose significant ecological and human health risks. The results emphasize the need for regulatory control, targeted monitoring, and sustainable soil management practices in the Indo-Gangetic alluvial plains.
PMID:41912927 | DOI:10.1007/s10661-026-15239-8
