Health risks of thallium in contaminated arable soils and food crops irrigated with wastewater from a sulfuric acid plant in western Guangdong province, China.

Thallium (Tl) contamination in soils poses a significant threat to human health due to the high toxicity of Tl and its ready assimilation by crops. Consumption of food crops contaminated with Tl is a major food chain route for human exposure. The health risks of Tl in contaminated food crops irrigated with wastewater from a sulfuric acid factory were investigated in this paper. Results indicate that long-term Tl-containing wastewater irrigation resulted in Tl contamination of arable soils and crops. The pollution load index values indicated that the arable soils were moderately enriched with Tl. Tl was highly accumulated in the crops. The content of Tl in the edible plant portions of crops ranged from 1.2 mg/kg to 104.8 mg/kg, exceeding the recommended permissible limits for food crops. The daily intake of metals (DIM) values of Tl for both adults and children via the consumption of the food crops except soya beans were higher than the reference oral dose (RfD) limit recommend by the United States environmental protection agency (US-EPA). Health risk index (HRI) values were generally higher than 1, indicating that health risks associated with Tl exposure are significant and assumed to be dangerous to the health of local villagers. Therefore, much attention should be paid to avoid consumption of these Tl-contaminated crops that can cause great potential risks.