喀斯特地貌土壤重金属污染负荷评价模型研究

Research on pollution load evaluation model of heavy metals in karst soil

为了解决喀斯特地貌土壤重金属污染负荷评价中的难点,在半机理模型——潜在污染指数模型(PPI)的基础上进行了改进。首先,将土地利用指数替换为重金属指数;其次,重金属的选择引入了健康风险理念;第三,考虑到喀斯特地貌土壤重金属的产生、迁移和衰减特性,对重金属指数、径流指数和距离指数的权重系数进行了优化;最后,引入潜在污染指数总量和潜在污染指数强度来进一步评价喀斯特地貌土壤重金属污染负荷。将改进的PPI应用于国内典型的土壤重金属污染地区(某喀斯特地貌地区小流域),发现6个典型重金属废渣堆的潜在污染指数总量差别较大,而潜在污染指数强度差异不大。两个指数的信息可以互为补充,在实际应用中,决策者可以根据具体需要,结合这两个指数制定合理的治理方案,该模型可为现阶段喀斯特地貌土壤重金属污染治理提供科学指导。

In order to settle the problems in pollution load evaluation of heavy metals in karst soil,the semi-mechanism model of potential pollution index model(PPI)was modified.Firstly,land use index was replaced by heavy metal index;secondly,health risks were considered for heavy metals screening;thirdly,considering the characteristic of heavy metal production,migration and attenuation,the weights of heavy metal index,runoff index and distance index were optimized;finally,total potential pollution index and potential pollution index intensity were introduced to further evaluate pollution load of heavy metals in karst soil.The modified PPI was applied to evaluate pollution load of heavy metals in a polluted area(a small valley in karst area).It was found that total potential pollution index of 6 typical slag piles varied significantly,while potential pollution index intensity was similar.The 2 introduced indexes served mutually.For application,decision-makers could took suitable measures according to specific situations by combining the 2 indexes,which could provide scientific guidance for pollution load evaluation of heavy metals in karst soil at present.