煤矿塌陷区不同充填模式土壤特征及修复评价

采集了安徽省淮南市大通煤矿塌陷区中化工垃圾充填(B)和煤矸石充填(C)两种充填修复模式以及作为对照区的人工混交林地(A)的表层土样,分析了其理化性质及这些土样中Cr,Cd, Cu,Pb, Hg的赋存特征,并对修复效果进行了评价。结果表明:(1)速效磷含量为:A区 >B区 >C区;碱解氮含量为:C区 >A区 >B区;重金属和交换性Na⁺为B区高于其他区域, B区土壤碱化度(ESP)高达22%。(2)研究区内土壤普遍呈碱性,碱解氮和速效磷严重缺乏,土壤肥力:A区 >C区 >B区。(3)土壤重金属污染:A区为轻度,B区属于中、重度,C区污染程度不一。重金属Cr, Cd, Cu, Pb总量不同程度超过淮南土壤背景值。(4)土壤修复效果C区优于B区,B区存在突出问题,亟待改善。

Soil Characteristics and Remediation Evaluation of Various Filling Modes in Coal Mining Subsidence Area

Three types surface soil from Datong coal mine subsidence in Huainan City of Anhui Province were collected for remediation evaluation. Sample A was from the control area with a mixture plantation, sample B was taken from an area with chemical waste filling, and sample C was taken from an area with coal gangue fillin. The physical and chemical properties, and the occurrence characteristics of Cr, Cd, Cu, Pb, and Hg of the samples were analyzed, and the environmental effects of the soil restoration were assessed. The results showed as follows:First, in the three samples, available P content in area A >area B >area C, but available N in area C >area A >area B, and content of heavy metals and exchangeable Na⁺ of area B was higher than in other areas, and in particular, the ESP(exchange sodium percentage) content was up to 22%; Second, high alkalinity of the filling soil was widespread, showing a serious lack of available N and P. The soil fertility in area A >area C >area B. Third, the levels of heavy metal pollution found in the soil showed that area A reached slight levels, area B reached moderate to high levels, and area C reached different types of heavy metal pollution. The total content of Cr, Cd, Cu and Pb in the soil was, to different degrees, greater than that found in typical Huainan City background values; Fourth, the effect of the soil restoration in subsidence sample C was superior to subsidence sample B, and the environmental problems of the soil in area B was severe, it should be improved promptly.