复垦地土壤重金属及类重金属的时间累积效应

Temporal cumulative effects of heavy metal and metalloid elements in covering soil of opencast coal mine reclamation area

为了揭示矿区复垦地土壤的重金属及类重金属的时间累积效应,文中以黄土高原丘陵沟壑区黑岱沟露天煤矿复垦地为研究对象,以空间代替时间的方法,在不同复垦时间的复垦地采集土壤样品,对矿区复垦地土壤的重金属及类重金属元素的时间变异性进行了研究。结果表明:复垦地土壤的重金属及类重金属元素的平均值均高于或略低于背景值,且均未超标;重金属Cu、Pb、Zn、Cd、Ni及类重金属As的累积量随着复垦时间的增加而减少(负累积效应),Hg及Cr的累积量随着复垦时间的增加而增加(正累积效应),Hg的累积效应更为明显,达到了+418.18%,Hg及Cr将成为限制复垦地再利用(农用)的主要限制因素;各种重金属及类重金属含量均处于安全等级,内梅罗指数均低于1,均处于清洁水平,内梅罗指数顺序为:PNNi>PNAs>PNCr>PNCu>PNZn>PNCd>PNHg>PNPb。

In order to study the cumulative effects of heavy metal and metalloid elements in covering soil of opencast coal mine reclamation area on the loess plateau,the heavy metal and metalloid elements were investigated at Hei-Dai-Gou Opencast Coal mine.By the way of space instead of time,the temporal variability of heavy metal and metalloid elements was as follows： The heavy metal and metalloid elements were higher than the average or slightly lower than the background value,and were below standard;Along with the increase of reclamation time,the accumulation of heavy metal Cu and Pb,Zn,Cd,Ni and metalloid As decreased（negative accumulation effect）,while the accumulation of Hg and Cr increased（positive accumulation effect）,among them,the cumulative effect of Hg was more apparent,to ＋ 418.18%,in the future,Hg and Cr would become main limiting factors of reclaimed land reuse（agricultural use）;All kinds of heavy metals and metalloid elements were in safe rank,Nemerow indices were less than 1,and were in clean level,The order of the Nemerow indices was PNNiPNAsPNCrPNCuPNZnPNCdPNHgPNPb.