Co,Ni,CrandVin25typicalsoilsofChinawerefractionatedintoexchangeable,carbonatebound(calcareoussoils),Mnoxidebound,organicallybound,amorphousFeoxidebound,crystallineFeoxideboundandresidualformsusingaseven-stepsequentialextractionprocedure,soastostudythedistributionofchemicalformsofthesemetalsaswellastheeffectsofsoilproipertiesonthedistribution.TheresultsshowedthatmostofsoilCo,Ni,CrandVwerepresentinresidualforms,andthedistributionratioaveraged48.2%forCo,53.0%forNi,81.5%forCrand68.7%forV.Thespeciationofheavymetalswasgreatlyinfluencedbysoilphysico-chemicalpropertiesandthechemistryofelements.Theresultsalsoindicatedthattherecoveryofmetalelementsbythesequentialextractionprocedurewassatisfactory,withtherelativedifferencebetweenthesumofsevenformsandthetotalcontentinsoilsaveraging9.5%forCo,12.8%forNi,6.6%forCrand7.2%forV.
