Tempo-spatial Characteristics of Soil Mercury in Beijing Plain, China from 2005 to 2018 and Their Influence Factors

Abstract

In order to understand the distribution characteristics and variations of soil mercury in Beijing plain, the contents of soil mercury in 2005, 2015 and 2018 were sampled and measured, and 270 analytical data were obtained. A combination of quantitative and qualitative analysis was used to explore the tempo-spatial variation of soil mercury, and to analyze the influence factors affecting the tempo-spatial characteristics of soil mercury. The results show that the contents of soil mercury in Beijing plain decrease from 0.093×10-6 in 2005 to 0.064×10-6 in 2015, and to 0.058×10-6 in 2018, which is close to or even lower than the soil background value in Beijing; the block-base ratios of soil mercury are 28.2%-29.9%, indicating that the spatial autocorrelation of soil mercury is moderate, and the spatial structure is affected by both structural and random factors; the spatial distribution of soil mercury in Beijing plain is characterized by “high content in urban areas, and low content in suburbs”; the mercury-containing substances imported from the outside into the soil are greatly reduced(input reduces), and the mercury in the soil is continuously lost through discharge, transformation and absorption(output continues), resulting in the continuous decline of the contents of soil mercury from 2005 to 2018; industrial production, human life, urban construction history and other human factors can aggravate the enrichment of mercury in urban soil, reflecting the impact of random factors; natural factors such as drainage basin and soil texture cause local differences in the distribution of soil mercury, reflecting the impact of structural factors.