Vertical Distributions Of Various Bacteria And Arsenic Species In Sediments Of Tuojiang River In Different Seasons

With the development of human society and economy, water pollution is faced around the world. In natural water, bacteria play a important part during the transference, circulation, biotransformation, and biomineralization in natural water system and sediments. And for the heavy metals, sediment is not only a reservoir but also a potential contaminative source. Therefore, the study of the population, category and distribution of bacteria as well as the transformation of heavy metals at the sediment-water interface (SWI) is very significant to learn the behaviors of environmental geochemistry.Tuojiang River is one of the largest branches of Yangtze River, its aquatic environment has been polluted seriously by a terrible accident of untreated wastewater discharges in 2004, lots of aquatic dead and the entironment was damaged seriously. The vertical distribution of bacteria and arsenic species in porewater and sediments were analyzed in this thesis, as well as the rule of their distribution. Finally, we try hard to provide a scientific evidence for the environment assessment and ecological recovery of Tuojiang River.The principal contents are included as following:1. The vertical distribution of various bacteria in sediments of Jintang, upstream of Tuojiang River in winter and summer was studied in this thesis.2. We studied the vertical distribution of arsenic species in porewater and sediments of Jintang, upstream of Tuojiang River in winter and summer, and compared them with the related factors.The conclusions can be summaried as following:1. The vertical distribution of virious bacteria in sediments of Jintang, upstream of Tuojiang River, shows that the number in the interface of porewater is more than in the substrate, the population of most bacteria in the sediments in winter is more than that in summer.2. The vertical distribution of arsenic species in porewater of Jintang shows that the content of As(III) in winter is obviously more than that in sunmmer; the content of As( V) is almost the same in winter and summer; the content of organic arsenic in winter is a little more than that in summer; the content of total arsentic in winter is obviously more than that in summer; the average content of arsentic of sediments in winter and summer is almost the same.3. The vertical distribution section plane of Fe and Mn in porewater of Jintang is very alike, it shows the evidently positive relativity. The main species of sulfur is ES,AVS and PS, the average content in winter and summer is ES