铜川三里洞煤矿煤矸石风化土壤重金属分布及污染状况分析

Distribution and Assessment of Heavy Metal Contamination in Weathered Soil in Sanlidong Coal Mine of Tongchuan

研究煤矿矸石地的土壤重金属分布及污染状况可为污染治理和植被恢复提供科学依据。通过测定陕西省铜川市三里洞煤矿煤矸石风化土壤中Cu,Cr,Cd,Ni,Zn,Pb共6种重金属元素的含量,应用地质累积指数法和潜在生态危险指数法对排矸场风化土壤污染状况进行了分析与评价。结果表明:在地形较平坦,排矸年限长,植被覆盖度大的地段,重金属元素含量较高,而且分布趋于稳定。在坡地,坡下部重金属富集和积累比较明显,一般坡下部重金属含量高于坡上部和坡中部。排矸场Cd污染最为严重,为中度或偏重度污染,且潜在生态危险水平也达到了重度或极重;Cu,Ni,Zn为轻度污染,Cr和Pb污染轻微,个别地段达到轻度污染,这5种重金属元素均达到轻度潜在生态危险水平。可见,该排矸场亟需加强重金属污染的预防和治理。

The research of distribution and assessment of heavy metal contamination can provide a scientific basis for pollution control and vegetation restoration.The contents of copper（Cu）,chromium（Cr）,cadmium（Cd）,nickel（Ni）,zinc（Zn） and plumbum（Pb） in weathered soil developed from coal gangue in Sanlidong coal mine of Tongchuan were measured.In this paper,the geoaccumulation index and potential ecological risk index were used to evaluate the soil pollution of gangue field.The results showed： the contents of heavy metals are higher and tend to be stable along with the length of stopping discharging the gangue increased,the terrain flatted and vegetation coverage increased.The accumulation of heavy metals was significant at the foot of the slopling land,the contents of heavy metals at the foot of slope were higher than the other sites.In the gangue field,the pollution of Cd was most severe,it was defined as moderate or lay particular stress degrees in the geoaccumulation index,and severe or extremely severe degrees in the potential ecological risk index;the pollution of Cu,Ni,Zn was mild,the pollution of Cr and Pb was slight,but some individual study areas were polluted mildly,and the level of pollution of all the five heavy metals were classified as light degrees by potential ecological risk index.Thus,it is necessary to prevent and control the heavy metal pollution for the gangue field.