Effect And Microbiology Mechanism Of Triclosan Pollution On Production Of Methane In Flooded Soils

Triclosan is a new kind of organic pollutant with widely usage and stable qualities,which will produce potential ecological risk after long-term accumulation.Methane is the most important greenhouse gas except CO2,while flooded soils are important sources of methane.Inland river sediments in Fuzhou City,Marsh of Minjiang Estuary and paddy soil in Town of Langqi were selected in this study to survey the pollution episodes,to program the anaerobic incubation by adding different concentrations of TCS(0,0.1ppm,1.0ppm and 10.Oppm),and to analyze microbial communities by DGGE method.The main results are as follows:(1)The detectable rates of TCS in sediments and marsh soils were all 100%,while the observed concentrations were in the range of 11.8 to 120.4μg/kg and 9.66 to 13.75μg/kg,that were of the moderate level and low level,separately.But TCS was not detected in paddy soils.The results of risk assessment showed that all the samples of sediments and marsh soils posed medium risk or high risk.It indicated that the contamination of TCS was serious in Fuzhou area.(2)The results of anaerobic incubation showed that adding TCS can promote the production of methane in flooded soils to some extent.To paddy soils and marsh soils,the maximum mass of product appeared when the concentration of TCS was 0.1 ppm.And when the concentration of TCS increased,the acceleration was weakened.To sediments,the maximum mass of product also appeared when the concentration of TCS was 0.1 ppm.However,other three groups showed no significant difference.The concentrations of TCS reduced slightly in all samples.It indicated that TCS was stable in aerobic conditions and was of difficult degradation.It also told thatthe reason of the acceleration of TCS to the production of methane was not that TCS could be used as carbon source of some kind of microbe.(3)The result of DGGE demonstrated that TCS could affect the microbial communities in paddy soils to some extent.It changed Similarities among different samples of eubacteria and archaebacteria.Diversity and uniformity of eubacteria changed slightly,while those of archaebacteria changed to some extent.The impact of triclosan to archaebacteria was greater than to eubacteria.It indicated that the influence of TCS to archaebacteria communities could be a cause of the acceleration of TCS to the production of methane in flooded soils.However,further research is still required to explore the exact mechanism.