Composition Characteristics And Spatial Distribution Of Trace Elemernts In Coal Mine Drainage,Guizhou Province

Trace elements have a distinguishing feature of low concentration in natural systems,which is difficult to form an independent mineral.In different occurrence of complex geological units and the environmental mediums,they have complicated occurrence states.After being minied and abandoned,mineral can be react with the air,water and bacteria.This progress will produce the coal mine drainage with different composition characteristics of teace elements and rare earth elements?REEs?.Then these coal mine drainage will entere the surface environments from the abandoned and producing mines.This study has explored the characteristics composition and spatial distribution of the trace elemernts in coal mine drainage in Guizhou Province for researching the transmission process of trace elements and REEs in the environments and provided theoretical basis for pollution control.From July to November in 2016,112 coal mine drainage samples of different types had been collected from different types of mines in different regions of Guizhou Province.The content of twenty kinds of trace elements and fourteen kinds of rare earth elements in coal mine drainage have been tested by Inductively Coupled Plasma Mass Spectrometry?ICP-MS?,and the softwares of Origin9.0,SPSS Statistics 20.0,Geokit and ArcGIS10.0 have been used to analysis and discusses the composition characteristics and the spatial distribution.The main results are as follows:?1?At different stages of mining and metallogenic background,the variable parameters of coal mine drainage are different,such as the pH,EC,TDS.Moreover,the composition characteristics and the spatial distribution also have a significant difference.The percentage of acid mine drainage in all samples is the highest.The variation range of water quality is relatively large,and the difference characteristics of water are obvious.The range of pH is large,which is related to the difference between high and low sulfur coal area.The value of Eh is relatively concentrated.There are reductive water in weak acid,neutral and alkaline coal mine drainage.EC,DO,salinity and TDS are close to the normal distribution,and the change rules of TDS is consistent with salinity.The contents and morphology of Fe and SO₄^2-are different,and they interact with the water quality of the mine drainage,especially with pH and Eh?2?The total rare earth elements contents??REE?in coal mine drainage have transited from light rare earth element?LREE?to middle rare earth element?MREE?obviously.With the increase of pH,the concentration of REE decreased significantly,and the content of the elements changed greatly under acidic conditions.In the acid condition,REE in water samples present the heavy rare earth element?HREE?enrichment in regions of Huishui-Longli-Pingtang.In other conditions and other areas,the rare earth elements of samples show the light rare earth element?LREE?enrichment or middle rare earth element?MREE?enrichment.Outliers of Eu and Ce are anomaly differences in various types and spaces of coal mine drainage obviously.In other conditions and other areas,outliers of Y in samples show a negative anomaly.The spatial distribution of rare earth elements in study area is of great difference.Under acidic conditions,the REE in these regions of Xishui-Jinsha-Zhijin-Anshun-HuishuiLongli-Tuyun-Pingba-Fuquan-Kaili presents obvious enrichment.Under weak acidic conditions,the differences of enrichment characteristics in various regions are not significant.In neutral and alkaline conditions,the REE in water samples at regions of Xishui-Renhuai-Qianxi is relative enrichment.?3?There are obvious differences in the types of trace elements in different coal mine drainage.The correlations between pH and trace elements have singnificant difference,and the mutual influence and connection of elements are diversity.At the same time,both of them are affected by coal mine drainage type.There are significant differences in content and spatial distribution between the different elements in the same types of coal mine drainage.In different coal mine drainage types,some elements show great difference in some areas.?4?There are significant differences in the part of trace elements in coal mines under different geological conditions.The relationship of REE and trace elements between coal mine drainage and the background conditions,including coal,rocks and soils,are closely related,and there are certain similarities and succession.From the characteristics of coal mine drainage,other sources of enrichment elements are existing.In the three main developed coal strata in Guizhou Province?Upper Permian Longtan formation,Lower Permian Liangshang formation,and Lower Carboniferous Xiangbai formations?,the rare earth elements in coal mine drainage are mainly light rare earth enrichment.Obviously,types and spatial characteristics of trace element enrichment are different.