Spatio-temporal variability and fractionation of vanadium (V) in sediments from coal concentrated area of Huai River Basin, China

The Huai fluvial system is known for its heavy metal pollution resulting from industrial activities. Here, we report V in surface sediments and sediment core from Huai River near the Huainan coal district. Sedimentation rate of 0.83 cm yr− 1 is indicated by 210Pb dating. The sediment core has recorded the V deposition spanned 60 years (1955-2014 CE). The downstream surface sediment has the highest V concentration of 100 mg kg− 1 in the study area. A sequential extraction procedure was applied to determine the fractionation characteristics of V in sediments. Vanadium primarily exists in the residual fraction, and the lowest proportion was observed in the weak acid soluble fraction. The results of enrichment factor and geo-accumulation index (Igeo) revealed that V in some Huai River sediments is considered as minor or moderately contaminated. The total concentration of V kept increasing since 1955 and reached a maximum value in around 2000, after which there was a decline with fluctuation until 2014.