Accumulation characteristics of tungsten (W) and its potential health risk assessment in the soil-vegetable system under field conditions

Abstract

PURPOSE: This work was performed to reveal the influences of the soil properties (OM, CEC, silt and clay content), on the translocation of W, from soil to vegetables, under agrarian system (soil to vegetables), in low acidic conditions. MATERIALS AND METHODS: A total of one hundred and thirteen (113) vegetable samples of (5) different types, and the corresponding surface soil samples, were collected from (5) main cities in Fujian Province of southeastern China. RESULTS AND DISCUSSION: The results showed that the total and available soil W ranged from 0.05 to 28.48 and 0.02 to 2.40 mg kg⁻¹, respectively, and were significantly correlated (r = 0.756**, n = 113). The W concentration in the vegetables ranged between 0.02 to 13.03 mg kg⁻¹, with an average of 0.59 mg kg⁻¹. Among the different vegetable types, the mean W concentrations were between 0.03 mg kg⁻¹ and 2.73 mg kg⁻¹. Lotus seed (Nelumbo nucifera) and spinach (Spinacia oleracea) contained the lowest (0.03 mg kg⁻¹), and highest mean W concentrations (2.73 mg kg⁻¹), respectively. Also, the W transfer from soil to vegetables based on (TFₐᵥₐᵢₗ) decreased in the order of radish (Raphanus sativa) (28.01) > spinach (Spanacia oleracea) (11.35) > potato (Solanum tuberosum) (1.36) > lotus root (Nelumbo nucifera) (0.77) > corn (Zea mays) (0.32) > lotus seed ((Nelumbo nucifera) (0. 30). CONCLUSIONS: Among the soil properties, the OM, CEC, and silt and clay content showed significantly negative correlations, with TFₐᵥₐᵢₗ, indicating that the CEC, silt and clay contents, and OM of the soils were the main soil properties influencing the transfer of W from the soil to the vegetable (edible parts), under field conditions. The estimated daily intake revealed that the local residents may be exposed to health risks by consuming leafy vegetable produced from the investigated areas; therefore, more attention should be given to the cultivation process and consumption of the leafy vegetable produced from these study areas.