[Environmental concerns on geochemical mobility of lead, zinc and cadmium from zinc smelting areas: western Guizhou, China].

Indigenous zinc smelting activity, widely spread in western Guizhou, China, had caused serious pollution of heavy metals of lead (Pb), zinc (Zn) and cadmium (Cd) in soil and water and posed risk to the local ecosystem. Geochemical distribution and mobility of Pb, Zn and Cd in soil, waste residue and waters were investigated in a small watershed in order to provide scientific base for the approach to pollution control and remediation. Concentrations of Pb, Zn and Cd in smelting residues averaged at 4 632 mg/kg, 8 968 mg/kg, and 58 mg/kg, respectively; whereas Pb 234 mg/kg, Zn 400 mg/kg and Cd 9.

[Limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou].

With indigenous zinc smelting waste residue, contaminated soil and background soil as test substrates, a pot experiment was conducted to study the growth characteristics of Lolium perenne and Trifolium pretense on these substrates. The results showed that the major limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou were the salt-alkali stress and the lower contents of organic matter, total N, available N and total K. The heavy metals in waste residue had a high concentration, but their available forms only occupied a small proportion, with low toxicity to plant but having potential harmful risk.