Transformation of the external source lead compounds in soil

The transformation of the external source in black soil, brown soil and meadow was studied through culture test. With the treatment of Pb (NO3)2, PbO, Pb3(CO3)2(OH)2 and PbSO4, the disabled Pb content of soil was high relatively at beginning of test, then lower quickly and reached equilibrium state gradually. With the treatment of PbS, the abnormal change of dissolve property might be related to the PbS oxidation. The dissolve properties of different lead compounds in black soil, brown soil and meadow were the same, which was: Pb(NO3)2PbO, Pb3(CO3)2(OH)2PbSO4PbS. The dissoluted Pb content did not have marked difference between PbO and Pb3(CO3)2(OH)2 (P0.01). After mixing with soil 90d, large parts of PbSO4 and PbS were not dissolved. pH value and PbS oxidation were the main factors controlling the dissolubility of PbS. The dissolution properties of Pb(NO3)2, PbO, and Pb3(CO3)2(OH)2, were expressed as: brown soilblack soilmeadow soil (P0.01). With treatment of Pb(NO3)2, the proportion occupred by Pb2+ was higher markedly than the other Pb treatments (P0.01). After 90d mixing with soil, with treatment of Pb(NO3)2 and PbO, the proportion occupied by Pb2+ could be high reaching 75.23%, and related with lowering of pH value and DOC content of the soil solution.