Research On The Remediation Of Combined Contamination Of Heavy Metals And Polybrominated Diphenyl Ethers By Bacillus Cereus

Combined contamination of heavy metals and persistent organic pollutants(POPs) and its corresponding environmental risk had arisen people's keen attention. Based on the severe contamination situation caused by heavy metals and deca-brominated diphenyl ether (BDE209) in water and soil of Guiyu, a famous e-waste(electronic waste) processing village in Shantou City, Guangdong Province, this study had researched disposal methods by using specific microorganism to simultaneously adsorb heavy metals and degrade BDE209. This research also focused on reciprocities and principles of the two pollutants during disposal procedure.Environment monitoring data of Guiyu indicated low qualities of water, soil, and farm plants that resulted from serious pollution of heavy metals and BDE209 there. Two strains of Bacillus cereus acclimatized from environmental samples were obtained and selected to do further researches. Combined Bacillus cereus showed prompt, efficient and stable adsorption character for low concentration of Pb(Ⅱ) and Zn(Ⅱ), and at certain extent for Cu(Ⅱ).Debromination of deca-brominated diphenyl ethers by Combined Bacillus cereus at aerobic circumstances was approved in this study. Combined Bacillus cereus could efficiently debrominate BDE209. Hydroxybenzene was detected in solution showing that BDE209 was degraded to be organics with lower molecular weight. Biodegradation process was delayed at presence of low concentrations of heavy metals but satisfying degradation effect could also be achieved. Results of analysis measures of GC-MS, ICP, UV scanning, FTIR, SEM, etc. indicated that biosorption and biodegradation were promptly and efficiently achieved, and hydroxy, aminoacyl, alkyl in cells' structure and aminophenol released by Bacillus cereus were considered to be most importance for this process.Influence of BDE209 concentration on adsorption rate was observed. Adsorption capacity was stimulated with existence of 1mg·L^-1 BDE209 and that started to decrease 4 hours after 10mg·L^-1 BDE209 was added.It was improved that activities of compound Bacillus cereus could alter the distributions of heavy metals and enhance their bioavailability in soil. 1mg·L^-1 of BDE209 sometimes favored the expectative alterations and that with concentrations of 5mg·L^-1 and 10mg·L^-1 depressed the alteration efficiency of compound Bacillus cereus. However, expected influences could be brought into play at certain degrees with the existence of BDE209.