摘要
煤矿区及其周边农田土壤重金属超标原因尚未达成共识,溯清煤矿区及其周边农田重金属之源,不仅对农田生态与环境保护具有较重要意义,而且对保障矿产开发利用、矿山企业发展、绿色矿山建设等具有较重要价值。以盂县煤矿区及其周边农田为研究对象,运用质普试验、经典统计学和地统计学等研究方法,通过农田土壤与煤、煤矸石和采矿废水中重金属含量及空间变化特征的对比,对研究区土壤重金属进行了溯源分析,不同样品重金属含量测定结果显示:除Hg外,煤粉的重金属含量是块煤重金属含量的1.05~1.99倍;全风化煤矸石重金属含量是新鲜煤矸石重金属含量的1.16~6.57倍;自燃煤矸石重金属含量是非自燃煤矸石重金属含量的1.19~9.20倍;除Cd,Pb外,泥质煤矸石重金属含量是砂质煤矸石重金属含量的1.34~4.78倍;采矿废水的重金属,除含较少量Pb外,其他重金属均未检出;土壤重金属含量低于煤粉、全风化煤矸石和自燃煤的重金属含量,但高于块煤和新鲜煤矸石重金属含量,远大于采矿废水的重金属含量。农田土壤重金属含量空间分布研究结果显示:不同距离农田样带土壤重金属含量变化规律基本一致;煤堆(井)、煤矸石山(堆)周边不同距离的农田土壤重金属含量主要符合指数模型;土壤8种重金属含量块金值C0均为正值,但受正基底效应的影响而变化较大;距离越远基台值C0+C越小,且Zn>Pb>Cu>Cr>Ni>As>Cd>Hg,空间变异性渐弱。重金属含量结构性因子随着距离增大而减弱,距离超过50 m后随机数据具有强烈的空间自相关,即土壤重金属含量受自然因素影响较大;距离小于50 m时,随机数据具有中等的空间相关性,即土壤重金属含量在受自然因素影响的同时还受人类活动的影响。不同距离农田土壤重金属含量的决定系数R2在0.50~1.00,|ME|和|MSE|接近于0,|ASE|与|RMSE|接近,|RMSSE|接近于1,表明半变异函数理论模型对试验数据的拟合效果较好,精度较高且预测值总体与测量值较为接近,准确地反映各情况下土壤重金属空间分布特征,因而保证了不同距离农田土壤重金属含量空间插值精度。研究结果表明,煤矿区及其周边农田土壤重金属主要源于母岩风化,煤矿开采不会造成大面积农田土壤重金属含量增加和超标。同时,运用矿物学与结晶学原理对所得结论进行了较科学的论证。
Soil heavy metal in coal mine area and its surrounding farmland exceeding the standard has attracted the attention of all circles of society.There are two different views on the reasons for this.Tracing the source of heavy metals in mining area and its surrounding farmland is not only important to farmland ecology and environmental protection,but also has great value to ensure the development and utilization of mineral,mining enterprises development and green mine construction.Therefore,for two different views,this research selected the farmland soil with coal mine area and its surrounding in Yu County as object.The research methods include mass’s test,classical statistics and statistical methods.Through the comparison of heavy metal content and spatial variation characteristics between farmland soil and coal,gangue and mining waste water,the soil heavy metal in the study area was traceability analyzed.The results of heavy metal content in different samples showed that except Hg,pulverized coal is 1.05-1.99 times larger than lump coal.The fully weathered gangue is 1.16-6.57 times of fresh gangue.The spontaneous combustion gangue is 1.19-9.20 times of the non-spontaneous combustion gangue.In addition to Cd and Pb,the mud gangue is 1.34-4.78 times higher than the sandy gangue.The heavy metals in mining wastewater,except Pb,were not detected.The heavy metal content of soil is lower than that of pulverized coal,fully weathered gangue and self-burning coal,but higher than that of lump coal and fresh gangue,and much higher than that of mining waste water.The results of spatial distribution of heavy metal content in farmland soil showed that the variation law of heavy metal content in soil with different distance was basically the same.The heavy metal content value of farmland soil at different distances around coal heap(well)and coal gangue mountain(heap)mainly conforms to the index model.The Nugget C0 of eight kinds of soil heavy metal content are all positive,but it varied greatly under the influence of positive basement effect.Farther away,the smaller the sill C0+C is,and Zn>Pb>Cu>Cr>Ni>As>Cd>Hg,the spatial variability is weakening.The structural factors of heavy metal content decreased with the increase of distance,and the random data was strongly spatial autocor-relation when the distance was more than 50 m,that is,the content of heavy metals in soil was greatly influenced by natural factors.When the distance is less than 50 m,the stochastic data has medium spatial correlation,that is,the content of heavy metals in soil is affected by natural factors and is also affected by human activities.The decision coefficient R2 of heavy metal content in farmland soil at different distances in 0.50-1.00,|ME|and|MSE|are close to 0,|ASE|is close to|RMSE|,the|RMSSE|is close to 1,which shows that the semi-variation function theory model has good fitting effect to the test data,the accuracy is high and the predicted value is close to the measured value,which accurately reflects the spatial distribution characteristics of heavy metal in soil under each case,thus ensures the spatial interpolation accuracy of heavy metal content in farmland soil at different distances.The results show that the heavy metals in the soil of the coal mine area and its surrounding farmland are mainly derived from the parent rock weathering,and coal mining will not lead to the increase of heavy metal content in the large areas of farmland and exceed the standard.At the same time,the conclusions obtained are scientifically demonstrated by using the principles of mineralogy and crystallization.
作者
刘政
赵文廷
王爱军
LIU Zheng;ZHAO Wenting;WANG Aijun(College of Land and Resources,Agricultural University of Hebei,Baoding071001,China;Key Laboratory of Farmland Ecology in Hebei Province,Baoding071001,China;Baoding Academy of Ecological Civilization In Hebei,Baoding071001,China;Center for Hydrogeology and EnvironmentalGeology,CGS,Baoding071051,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2018年第S2期532-545,共14页
Journal of China Coal Society
基金
国家地质大调查基金资助项目(DD20160335)
关键词
农田土壤
重金属
煤矸石
废水
煤矿
溯源分析
farmland soils
heavy metals
gangue
outlet water
coal mine
traceability analysis
