[Effects of Hg contamination on paddy soil microbial and enzymatic activities].

With pot experiment, the microbial and enzymatic activities in two paddy soils were investigated at different Hg2+ loadings. The results showed that after harvest, all measured microbiological and enzymological indices including microbial biomass carbon, respiration rate, and activities of urease, acid phosphatase, and dehydrogenase in test soils were increased under low Hg treatments ( <2 mg Hg x kg(-1)) while decreased under high Hg treatments ( > or =2 mg Hg x kg(-1)), except the basal respiration and metabolic quotient were partly increased with increasing Hg level. Among the test indices, soil microbial quotient was a microbiological index more sensitive to Hg contamination.

Role of soil rhizobacteria in phytoremediation of heavy metal contaminated soils.

Heavy metal pollution of soil is a significant environmental problem and has its negative impact on human health and agriculture. Rhizosphere, as an important interface of soil and plant, plays a significant role in phytoremediation of contaminated soil by heavy metals, in which, microbial populations are known to affect heavy metal mobility and availability to the plant through release of chelating agents, acidification, phosphate solubilization and redox changes, and therefore, have potential to enhance phytoremediation processes. Phytoremediation strategies with appropriate heavy metal-adapted rhizobacteria have received more and more attention.