Abstract:

Heavy metal pollution poses a significant challenge to the safety of agricultural product. This study focuses on Tian’e County, Guangxi, as a study entry to reveal the ecological risks associated with heavy metal contamination in crops. In this study, sixty sets of rice and corn samples and their corresponding rhizosphere soils were collected for analysis. The contents of five heavy metals, Cd, Cr, Hg, As, and Pb, were measured. Data analysis was performed using multiple approaches, including the geo-accumulation index, bioconcentration factor, and correlation analysis. The results indicate that except of Hg, levels of Cd, Cr, As and Pb fall within acceptable limits of food safety, with Cr being the most prevalent at an average concentration of 0.094 mg/kg. Notably, Cd exhibits a high variation coefficient of 103%. In general, rice seeds contain higher concentrations of Cd, Hg, and As than the corn seeds. The soil was detected to have an acidic environment with a high organic nutrient content, and shows a moderate Cd contamination. Most heavy metals in the soil were in residual forms, but Cd ions demonstrated increased activity. Moreover, the crops display a pronounced ability to accumulate Cd and Hg, and the bioconcentration factor of heavy metals in clastic rock areas was higher than in the carbonate areas. Correlation analysis demonstrates that a strong positive correlation existing between the Hg content in rice and the Cd concentration in rhizosphere soil. Additionally, the soil pH and organic content considerably influence the heavy metal levels in crops. Therefore, adjusting soil acidity appropriately and reasonably utilizing organic fertilizers can effectively mitigate heavy metal pollution risks, which was crucial for ensuring the safety of agricultural products.

Key words: heavy metal element, crop, Tian’e County,Guangxi, bioconcentration factor, influencing factor