Immobilization Of Lead And Cadmium By Alishewanella Sp. WH16-1 In Pb、Cd-contaminated Soil

Currently, the rapid development of industry and agriculture has caused large area soil lead and cadmium pollution. This has caused the decrease in crop quality and the productivity and endangered human health through food chains. So it is urgent to solve soil remediation problems. The bio-remediation of heavy metal pollution is one of the most larger green remediation technology, it has a good application prospect.This study discussed the effect of bacteria Alishewanella sp. WH16-1 on lead(cadmium)-contaminated soil. The main results were as follows:1) The strain Alishewanella sp. WH16-1 was isolated from mine soil and exhibited high resistances to many heavy metals, especially to Pb2+(2070 mg/L) and Cr(VI)(2340 mg/L). Alishewanella sp. WH16-1 could removed 64.33 % cadmium from culture solution containing 9 mg cadmium/L and 84.13 % lead from culture solution containing 100 mg Pb2+/L in 72 h, respectively.2) In rice pot experiment, compared with the uninoculated Cd2+-added paddy soil, the exchangeable and carbonate bound Cd in the Cd2+-added paddy soil incubated with strain WH16-1 for 120 days significantly decreased by 13.80 %(P<0.05) and decreased by 4.56 %, respectively. Meanwhile, the Fe-Mn oxide-bound, organic matter-bound and the residual fractions in the Cd2+-added paddy soil incubated with strain WH16-1 significantly increased by 13.97 %, 13.80 % and 45.00 %(P<0.05), respectively. Compared with the uninoculated Cd2+-added paddy soil, the Cd concentrations of rice from the Cd2+-added paddy soil incubated with strain WH16-1 significantly decreased by 24.70 %(P<0.05).In rice pot experiment, compared with the Pb2+-added paddy soil uninoculated with strain WH16-1, the exchangeable and carbonate bound Pb in the paddy soil incubated with strain WH16-1 for 120 days decreased by 14.04 % and significantly decreased by 10.69 %(P<0.05), respectively. Meanwhile, the Fe-Mn oxide-bound was significantly increased 4.47 %, while organic matter-bound and the residual fractions increased by 19.40 % and 22.78 %(P<0.05), respectively. Compared with the uninoculated Cd2+-added paddy soil, the Pb concentrations of rice from the Cd2+-added paddy soil incubated with strain WH16-1 was significantly decreased by 26.18 %(P<0.05).3) In tobacco pot experiment, compared with the Cd2+-added soil uninoculated with strain WH16-1, the Cd concentrations in the leaves of tobacco in Cd2+-added soil incubated with strain WH16-1 for 120 days was significantly decreased by 52.94 %(P<0.05). While in the tobacco field experiment, compared with soil uninoculated with strain WH16-1, the Cd concentrations in the leaves of tobacco in soil incubated with strain WH16-1 for 90 days was significantly decreased by 25.00 %(P<0.05).Those results suggested that Alishewanella sp. WH16-1 can reduce the bio-availability of Pb and Cd in contaminated soil. Our study provide a theoretical and practical countermeasure for the large-scale microbial remediation of contaminated in the future.