Transformation And Mobilization Of Arsenic And Antimony In Soils Mediated By Microorganisms

Arsenic?As?and antimony?Sb?pollution is one of the most common environmental concerns in the world,which can be converted and transferred in environmental soil and groundwater.Environment contamination with As and Sb for the modal transformation of As and Sb in indigenous microorganisms and environmental migration plays a key role,has proven the indigenous microbial properties to control the As and Sb pollution and environmental restoration is of great significance.In this paper,from the high arsenic pollution areas of aerobic arsenic reducing bacteria Pantoea sp.IMH and facultative strains Shewanella sp.ANA-3 as the main research object,the further study of its under different environmental conditions on the morphological transformation characteristics and its mechanism of arsenic and antimony,provide theoretical support for repair of groundwater.The pourpos of this study:?1?Pantoea sp.IMH in different physiological states,the migration and transformation of arsenic antimony in soil were studied;?2?The release rule and reduction mechanism of arsenic iron in arsenic isolated system were studied under the action of Pantoea sp.IMH;?3?The morphological transformation and release of arsenic and antimony were investigated in the anaerobic condition of the facultative strain Shewanella sp.ANA-3.The results of the study are as follows:?1?In order to detect the impact on the arsC in Pantoea sp.IMH cluster with exists As?V?,Sb?V?,Sb?III?,besides,Sb?V?/Sb?III?both do coexist also detected.?35?arsC genes showed about 2–3 fold higher expression levels in presence of 1mM As?V?,Sb?III?,Sb?V?/Sb?III?than Sb?V?.Besides,?35?arsC gene resulted in almost no expression while1mM Sb?V?exist,indicating that?35?arsC gene can not contribute to the As resistance.This may be related to their structure.Because of As?V?and Sb?V?have different atomic structures.Therefore,the system containing only arsenic and the release of arsenic incubation with IMH was discussed.The result showed that IMH could not reduce Fe?III?to Fe?II?,IMH could not reduce the As?V?on the solid but in the liquid phase.?2?In the soil of arsenic and antimony co-existence,it was found that the strain Pantoea sp.IMH living bacteria system could soon reduce a large number of As?V?to As?III?,but could not reduce Sb?V?to Sb??40??40??40??.In the dead cell system,IMH could reduce very little As?V?to As?III?,no Sb??40??40??40??was mersured.The amounts of total As(506.8?g·L^-1)and total Sb(821.1?g·L^-1)in the dead cell system were approximately four times higher than that in the living cell system(As=155.2?g·L^-1;Sb=364.8?g·L^-1)and the abiotical control(As=57.6?g·L^-1;Sb=271.1?g·L^-1).This observation maybe attributed to the biomolecule released from the deadcells which enhanced As and Sb release.?3?Under anaerobic conditions,the facultative strain Shewanella sp.ANA-3 was studied,and the release rule and reduction of arsenic in soil were studied.It was found that ANA-3 was able to reduce As?V?to As?III?,Sb?V?to Sb?III?and Fe?III?to Fe?II?,but the ANA-3 only reduced the dissolved arsenic instead of the adsorbed arsenic.