Study on the Evaluation of Heavy Metal Pollution in Soil of Tea Plantations in Karst Mountain Areas Based on GIS

摘要

To understand the soil environment quality of tea producing region in Plateau Mountainous area, the evaluation model of heavy metals pollution in soil was built by adopting both the single pollution index method and Nemerow multi-factor index method combined with ArcGIS Geostatistical Analyst and Model Builder Geoprocessing, which realized the modeling and automation of the soil environment quality. The content levels and spatial distribution characteristics of heavy metals such as Hg, As, Cd, Pb and Cr were analyzed though choosing typical research area. The results showed that Nemerow multi-factor index was 0.502, belonging to clear level and all the mean values of soil heavy metal elements belonged to clear level. The coefficient variation of Pb was the biggest, which indicated that the external pollution was remarkable. The correlation coefficient of Cd and Pb was the biggest, presenting a character of the same source of pollution. The high content of Cd was distributed in the north. There were different degrees of point source pollution of heavy metals in parts of the east, north and west, and there was no soil heavy metals pollution in the south.