The Speciation Of Mercury In Greenbelt Soil Of Chengdu And Its Affecting Factor

Mercury is one of the most toxic heavy metal pollutants in the environment. The main anthropogenic sources of mercury in urban soils come from metal production, chlor-alkali, power plant, coal burning and waste treatment. The mobility and bioavailability of mercury depend on its speciation in soil. The species of mercury in soils is controlled by general soil characteristics and other factors. However, the distinction of soil zone and soil depth has been ignored by some reseach on mercury species in urban soil, few research was undertaken to concern the relationship between mercury species and general soil characteristics in greenbelt. The present paper focus on mercury speciation in the greenbelt soil of Chengdu and some affecting factors. The contents and distribution of total mercury, mercury species as well as general pyhsico-chemical parameters in each soil zone were systematically investigated. Pearson correlation factors were calculated to assess relationships between Hg species and general soil characteristics. From this paper, it was concluded as follows:(1) A low-cost procedure was developed for the speciation of mercury with good accuracy and pertinency.(2) Urban greenbelt soil in Chengdu is alkaline while suburb greenbelt soil is acidic; the contents of organic matter and total sulfur in surface soil are higher than that in sub-surface; the total sulfur contents in surface urban greenbelt soil are close and much higher than that in suburb greenbelt.(3) The maximum means for total mercury in both surface and sub-surface soil were obtained in public greenbelt, in which there was no significant difference for total mercury contents between surface and sub-surface soil. There was a significant positive correlations between total mercury and total sulfur in both surface and sub-surface soil of each zone.(4) The following characteristics were obtained in all greenbelts except for public greenbelt: residual Hg＞element Hg＞alkali soluble Hg, which consist of main species in Chengdu greenbelt soils. The maximum value of alkali soluble Hg/total Hg was obtained in soil of agricultural zone.(5) In surface greenbelt soil,The distribution of Hg species in such soil was mainly affected by themselves rather than other physico- chemical parameters. In sub-surface greenbelt soil.The distribution of Hg species in such soil was controlled by themselves and other factors.This study is of significance for environmental evaluation and remediation for mercury contamination.