The distribution and speciation characteristics of vanadium in typical cultivated soils

Abstract

ABSTRACT The contents and chemical speciation of vanadium(V) in different types of soil and soils with different particle were studied by the modified BCR method. The results indicated that the V content was in the order of as red soil > cinnamon soil > chernozem soil, and the content of V in red soil was as high as 264.9 mg/kg, which posesa potential risk to the environment and biosecurity. In cinnamon soil, V exhibitedan obvious gradation effect; that is, the content of V in fine particles was higher than in large particles. In addition, V(IV), with low toxicity, accounted for more than 87% of the total V in the three types of soil, and most V existed in the residual fraction. The pH was the main factor affecting the V valence state in the soil, and when the environmental conditions change due to various agricultural measures, such as applying fertiliser, long-term cultivation and intensive irrigation, V(IV) is easily oxidised to V(V) with high toxicity, and reduceable and oxidisable V is converted into an acid-soluble fraction, which leads to increased bioavailability and a potential threat to the environment. Therefore, it is necessary to strengthen environmental risk assessments and monitoring of heavy metals in cultivated soils, especially in areas with high background values.