Vanadium In Coal Mining Area:Distribution,Modes Of Occurrence,and Environmental Behavior

Vanadium in coals may have potential environmental and economic impacts.However,comprehensive knowledge of the environmental geochemistry of V in coal mining areas is lacking.In this study,>2,900 reported Chinese coal samples were collected from published papers to investigate V concentration in Chinese coal.21 coal samples of different coal ranks were collected from nine provinces in China,with the aim of studying the abundance,chemical speciation and combustion behavior of V in coals by sequential extraction and combustion experiment.In the Anhui coal mining area,sediment samples from the Huai River near the Huainan coal district,as well as soil and fish samples from Huaibei coal mining area were collected to study the concentration,distribution,chemical speciation,transformation and environmental effect of V in coal mining areas.In addition,as a contrast,the soil from the Yellow River Delta and aquatic organism samples from the Yellow River Estuary and Laizhou Bay,impacted by petroleum production,were also collected to study the geochemistry of V in petroleum-producing regions.The major findings of the present research work were as follows:(1)With coal reserves in individual provinces as the weighting factors,V in Chinese coals was estimated to have an average abundance of 35.81 ?g/g.The concentrations of V in Chinese coals were categorized into depleted,normal,and slightly enriched based on concentration coefficients.(2)Silicate-bound V had the highest fraction among six operationally defined modes of occurrence of V extracted from coal samples.With increasing of coal rank,organic matter-bound V exhibited declining trends.We found that V and Cr were highly correlated in the coal samples,which might be attributed to the fact that silicate-bound and organic-bound V and Cr are the leading modes.(3)The Chinese V emission inventory in the last decade during coal combustion and the global V emission flux by different sectors were estimated.Vanadium emissions by electric power plants are the largest contributor.The relationship between the chemical speciation and combustion behavior of V,as well as the relationship between volatilization ratios of V in coals and coal rank,was revealed.(4)The sediment core in the Huai River has recorded V deposition spanning 60 years.The concentrations and distribution of V in soils and fish from Huaibei coal mining area were investigated to reveal the impact of coal gangue and coal-fired plants on the V.The impact of oil exploitation on V in soils and aquatic organisms was also studied.(5)The results of enrichment factor and geo-accumulation index(Igeo)tests revealed that:some Huai River sediments were considered to have minor or moderate contamination with V;no V pollution was found in soils from the Yellow River Delta and Huaibei coal mining area;the mean concentrations of V in fish in the Yellow River Estuary were found to be significantly higher than the results of Huaibei coal mining area;through estimation of daily intake of V via fish consumption,the V contamination level of fish samples from both the Yellow River Delta and Huaibei coal mining area fell within an acceptable range,indicating no potential hazard to human health.