旅游活动对香格里拉景区土壤重金属污染的影响
Impact of Tourist Activities on Heavy Metal Pollution of Soil in the Shangri-La Scenic Area

为了解旅游活动对香格里拉景区土壤重金属的影响，在测定土壤重金属含量的基础上，结合相关分析解析重金属的来源，并采用内梅罗综合污染指数法和污染负荷指数法评价了重金属污染特征.结果表明：① 研究区混合样中重金属As，Hg，Cd，Cu，Cr，Pb和Zn的平均含量分别为10.16，0.291，0.52，38.67，83.78，42.26，130.27 mg/kg，其中Cu，Cd，Cr，Pb和Zn的平均含量超过对照样的13.3%，44.8%，10.6%，15.4%和13.9%，Hg，Cd，Cr以及混合样中的Cu，Zn的含量均超过了迪庆州土壤背景值，各样点Hg含量超过背景值7.45~7.53倍. ② 土壤重金属的单项污染指数从大至小表现为：Hg，Cd，Pb，Zn，Cu，Cr，As，最高污染系数污染程度从大至小表现为：Hg，Cd，Cr，Zn，Cu，Pb，As，Hg为研究区第一污染物. ③ 混合样点的平均综合污染指数和污染负荷指数分别为2.7(中度污染) 和1.06，对照样平均综合污染指数和污染负荷指数分别为1.54(轻污染) 和0.86，研究区混合样的整体污染程度高于对照样. ④ 研究区重金属Cu，Cr和Zn的主要污染源可能是旅游活动和生活产生的固体垃圾污染，如塑料制品、玻璃瓶、泡沫、卫生纸等；干湿沉降是Hg进入土壤的主要途径，旅游活动加剧了土壤中Hg的污染，导致研究区土壤Hg污染最严重.
In order to reveal the impact of tourist activities on heavy metal pollution of soil in the Shangri-La scenic area, we determined the heavy metal contents of soil samples. Then, we combined correlation analysis with the Nemerow multi-factor index method and pollution load index to track the sources of pollution and to evaluate the characteristics of heavy metal pollution. The results showed that the average contents of As, Hg, Cd, Cu, Cr, Pb and Zn of the mixed soil samples in the Shangri-La scenic area were 10.16, 0.291, 0.52, 38.67, 83.78, 42.26 and 130.27 mg/kg, respectively and that the average contents of Cu, Cd, Cr, Pb and Zn in the mixed samples were 13.3%, 44.8 %, 10.6%, 15.4% and 13.9% higher than in the control samples. Besides, the contents of Cd, Hg and Cr of each sample and the contents of Cu and Zn of the mixed samples in the study area were higher than the background values of these elements in the soil of Diqing Prefecture, and Hg content of the soil collected at various sampling sites exceeded the background value by 7.45~7.53 times. Single pollution index for the performance of heavy metals was in the order of Hg > Cd > Pb > Zn > Cu > Cr > As. The Nemerow multi-factor index of the mixed samples was 2.7, which belongs to 'moderate pollution', and their pollution load index was 1.06, while those of the control samples were 1.54 (light pollution) and 0.86, respectively, indicating that the composite samples of the study area represented a more serious degree of contamination than the control samples. The main sources of the heavy metals Cu, Cr, and Zn in the study area may be solid waste generated by tourist activities and domestic refuse, such as plastics, glass, foam and toilet paper. Dry and wet deposition was the main pathway of Hg into the soil. Tourist activities intensified Hg contamination of the soil