Leaching　of　the　Residual　Mercury　in　the　Polluted　Soils　on　Urban　Environment

Abstract

This　study　is　to　investigate　the　leaching　Qf　residual　mefcury　in　environmental　surface　soils．The　background　concentra・tion　ill　geochemical　soils，which　was　derived　from　crust　mother　rock，was　about　O。03ppm　and　background　concentration　in environment　urban　soils　was　about　O．12ppm。The　soils　from　the　sites　of　university，hospital　and　old　military　building　trace in　urban　areas，which　have　been　treated　with　mercury－containing　chemicals　for　many　years，contained　over　O・5ppm mercury，in（licating　the　neither　leaching，nor　volatilization　of　mercury　played　a　si墓nificant　role．Binding　forms　of　resi（iual mercury　in　surface　soils　ofurban　environment　show　mainly　that　mercury　chloride，organism bound　Hg，and　mercuric　sumde occurring　in　the　studied　soils　could　be　identified　by　their　thermal　release　behavior，Leaching　experiments　with　puri丘ed water，week　acid，acid　rain　and　seawater　did　l／ot　extracted　mercury　species　o▽er　O．1％．The　re＄ults　obtained　from　this research　were　found　that　the　residual　mercury　in　soils　was　chemically　stable　in　urban　environment．However，it　was　afraid that　the　polluted　soils　contained　over5ppm　residual　mercury　are　produced　the　leaching　over　the　o翫cial　environment standard　leve1，0、0005pprn．