Abstract:
This paper is the result of environmental geological survey engineering.
Objective This study aimed to understand the stability of heavy metal pollution in farmland soils surrounding industrial zones. A total of 100 surface soil samples were collected and analyzed for the total concentration and speciation of Pb, Cr, As, Cd, and Hg as well as their association with clay minerals.
Methods The extent of pollution and stability of farmland soils and health risks associated with the soil and wheat cultivated in these soils around Wuji Tannery, Xinji Tannery, Handan and Wuan Metallurgy, Guangping Chemical Plant, and Neiqiu Chemical Plant were evaluated. The evaluation was conducted using the single−factor index method, soil mineral evaluation method, and health risk assessment model.
Results The analysis revealed high concentrations of Cr in Wuji Tannery soil, Hg in Neiqiu and Guangping Chemical Plant soil, and Cd and Hg in Wuan Metallurgy soil. A significant correlation was observed between heavy metals, particularly those in the residual fraction, and clay minerals such as montmorillonite, chlorite, and illite. Clay minerals exhibited high retention of Cd and Hg but low retention of Pb and As. Additionally, clay minerals in two soil samples from Wuji exceeded the Cr retention capacity Human health risk assessments indicated that soils posed a noncarcinogenic risk (1.02) to children via oral and dermal exposure. Moreover, the cancer risk index, with wheat as the intake medium, exceeded the acceptable limit (1×10−4) for both adults (5.16×10−4) and children (6.44×10−4).
Conclusions There is a positive relationship between heavy metals and clay minerals. Therefore, residents in industrial areas, particularly those who rely on wheat as a staple food, should pay close attention to the Cd content in wheat.
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