Abstract:

Temporal and spatial variability characteristics of soil mercury content in Beijing urban for 24 year interval (1987—2011) were evaluated using geostatistics and geographic information system(GIS). Results indicate that there is remarkable change that soil mercury content presents obvious decline along with temporal process because of the Energy Consumption Structure’s change of Beijing City. From 1987 to 2005, soil mercury content decreased markedly in the study area mainly because of energetically implementing the measure of factory relocation and Coal to Gas. The average content of soil mercury decreased from 1.291 μg/g to 0.556 μg/g. But there is slight change that soil mercury content decreased from 0.556 μg/g to 0.490 μg/g in the period of 2005—2011. The range of high value area of soil mercury content is reducing within the second ring road of Beijing from 1987 to this day. From 1987 to 2005, soil mercury within the second ring road showed visible depletion that soil mercury content decreased by more than 1 μg/g. After 18 years the area of Grade Ⅲ and over Grade Ⅲ standard diminished from 142.22 square kilometers to 53.59 square kilometers. Compared with 2005, only soil mercury in the area of north-central part within the second ring road and southwest within the third ring road has relatively significant depletion in 2011 that soil mercury content decreased by more than 0.3 μg/g. The area of Grade Ⅲ and over Grade Ⅲ standard has diminished to 40.51 square kilometers after 6 years.

Key words: Beijing urban, soil mercury content, spatio-temporal variability