Abstract:

     It`s very important to study the factors that affect the transport of different forms of Pb in the pedogenetic process to understand geochemical behaviors of lead. In this article the distribution of the different forms of Pb in yellow soil profiles in Chengdu economic zone agro-ecosystems from Sichuan was been described, and the factors controlling the different forms’ transport and transformation were also been discussed. We focus on the distribution features of lead species in yellow soil profiles in Chengdu agro-ecosystems in Sichuan Province in order to assess the ecological safety. The results showed that the total Pb was enriched in the surface and was stable in the deep. In yellow soils, the main existing forms of lead were residual state and Fe-Mn oxidual state. And the increasement of total Pb led to the content of stable state Pb increasing. pH has significant influence on the transferring of Pb species, especially for the carbonate Pb. The total organic carbon and clay minerals contents also effect on transferring of Pb. The bioavailability and the mobility index for yellow soil are also low, which suggest that the cultivated soils have certain harm to the plant and the humanity.

Key words: lead, form, distribution feature, yellow soil profile, Chengdu economic area, pH, TOC, soil texture