Study Of Urban Soils Mercury Species

Mercury is very harmful to human beings, animals and plants. It is well known that the Minamata disease happened in Japan was caused by mercury pollution. More than 90% of mercury emitted to the atmosphere by the combustion of fossil fuels falls into the terrestrial ecosystem, and mercury originated from industrial and agricultural production may also enter the terrestrial ecosystem via various ways. As a result, the terrestrial ecosystem has become a recipient of mercury pollutant. Mercury in the polluted soils can get into the bodies of men and animals through food chains, and the potential damages are getting more serious.Based on the analysis of total mercury in the soil, this thesis gives further study into different formations of mercury and makes the following conclusion:1) According to mercury contents (from high to low), the districts in Chengdu can be listed in the following order: Jinjiang> Wuhou>Qingyang > JinniuvChenghua>Longquan. The soil in Jinjiang District is polluted most seriously, those in Qingyang and Wuhou districts are less seriously polluted, and those in Jinniu , Longquan and Chenghua districts are clear .2) The proportion of different formations of mercury are as follows:The soluble:0.77%;the acid soluble: 16.72%;the alkali soluble: 19.00%;the nitric acid soluble:0.54%;the residual :62.97%.3) The value of PH has obvious and regular impact on the soluble mercury: The content of soluble mercury of most soil sample falls when the value of PH rises.4) The content of mercury for sweet potato samples has the same change to the total mercury and the available mercury in soil, but the content of mercury for lettuce samples has obviously different change. This shows that the mercury in lettuce stem sample is mainly from soil and is probably influenced by other environmental factors. The mercury in dust may have contribution to it, but the mechanism needs for further study.