硫磺矿废弃地复垦土壤重金属含量演变规律研究

以西南地区某硫磺矿废弃地复垦土壤为研究对象,连续采集了2015、2016年土壤表层样品126个、50个,利用经典统计分析、单因子指数(P_i)和内梅罗综合指数(P_n)来评价复垦土壤5种重金属的污染程度,并利用经验贝叶斯克里格法进行空间预测,旨在探索复垦土壤重金属含量时序演变规律及其影响因素。结果表明,相较于2015年,2016年各土壤重金属变异性均增大,Cd变异系数高达1.04。由P_i和P_n值可知,Cd、Ni是研究区主要污染因子,且2016年P_n为3.05,土壤污染趋势加重。从重金属全量角度来看pH与有机质的变化可能对表层土壤重金属的演变具有一定指示作用。根据研究结果,可知复垦土壤pH增加0~1个单位,有机质含量提高2%左右时,有利于改善土壤环境质量。建议后续治理中,在土壤酸化严重、有机质含量较少地区可适当采取一定措施进行改善。

Variations of heavy metals in the reclaimed soil from a sulfur mine wasteland

In this paper,126 reclamation soil samples were collected from a sulfur mine wasteland in southwest China in 2015 and 50 samples were continuously collected in 2016.The classical statistical analysis,single factor index (Pi) and Nemerow comprehensive index (Pn) were used to evaluate the degree of pollution caused by five heavy metals in the reclaimed soil and the spatial prediction of heavy metals in the soil was explored using empirical Bayesian kriging method in order to explore the regularity of heavy metal sequence and its influencing factors in the reclaimed soil.The results showed that the variation coefficients of heavy metals increased compared with those in 2015 in which Cd even had a variation coefficient up to 1.04.According to the values of Pi and Pn,Cd and Ni were the main pollution factors in the study area.The Pn was 3.05 in 2016,indicating aggravated soil pollution.Considering all heavy metals as a whole,the change of pH and organic matter may indicate the variation trend of heavy metals in the surface soil.Based on this research,an increase of the soil pH by 0-1 unit and the organic matter content by about 2％ indicated the improvement of the soil environmental quality,suggesting that in subsequent management,certain measures should be taken into account for improving soil quality in the area where the soil acidification is serious and the content of organic matter is low.