Comparative study on various methods of evaluating heavy metal pollution in urban topsoil

There are a lot of evaluation methods of heavy metal pollution in the soil.Since single method has certain limitations and deficiencies,geo-accumulation index method,nemerow comprehensive pollution index method and potential ecological risk index method were used to evaluate eight heavy metal pollution in different functional areas and at different altitudes,meanwhile,the evaluation results of three methods were comprehensively compared.The results showed that pollution degree of five investigated functional areas were taking the order of industrial park traffic area park green area living area mountainous area.Pollution degree of eight elements were taking the order of HgCdCuCrPbZnAsNi.Eight heavy metal elements caused moderate pollution in the investigated area,and with altitude increasing,the pollution degree of eight heavy metal decreased rapidly.