[Study of the fluorescence characteristics of DOM from the Yangtze River and Jialing River around Chongqing's urban areas].

The fluorescence emission and excitation emission matrix (EEM) technologies were used to characterize the dissolved organic matter (DOM) in the water body of the Yangtze River and Jialing River around the Chongqing urban areas from April to August 2008. Concerning about the accidents of the Wenchuan's Earthquake in May and Tangjiashan Yansaihu's effects in June, and the high water period time in the summer in two months of July and August, from the EEM obtained from each sampling station and time, the composition, distribution and their changing features of the DOM in the two rivers were investigated as combined with the water samples' environmental parameters such as pH, DO, DOC with EEM's fingerprint features, f(450/500) etc; finally the bio-environment behavior effects of the three types of fluorescence peaks were elaborated, where humic-like, fulvic-like, and protein-like from the five sampling stations' EEMs during the five months were given detailed representation. From the experimental results obtained, the fluorescence peaks are mainly composed of two types of fluorophores: humic-like and protein-like in the two rivers around the Chongqing urban areas during the investigation in five months, the protein-like's peaks value in Jialing River is higher than the values in the Yangtze River, and all the fluorescence peaks in the two Rivers' water body decrease more or less after the two Rivers join in Chun Tan sampling station; the protein-like peak is notably higher after the "5 x 12" earthquake period time including May and June and high water period time, which mainly originated from terrestrial sources, but its intensities decreased observably while the water bodies of the two rivers joining together in the Chao Tianmen and Chun Tan's sampling station.

[Movement and transformation of heavy metals in water-sediment in water-level-fluctuating zone of Three Gorges Reservoir Area].

According to the off-season regulation model for Three Gorges Reservoir, the characteristic of movement and transformation of Cu, Pb, Cd and Cr in sediment of water-level-fluctuating zone of Three Gorge Reservoir Area was investigated. The results indicated that the chemical fraction composition characteristics of heavy metals are different. Cu mainly existed in organic/sulphidic fraction and residual fraction; Pb mainly existed in carbonates, Fe-Mn oxides and residual fraction; Cd mainly existed in carbonates and Fe-Mn oxides fraction; Cr mainly existed in residual fraction. In flood season, the exposure of sediment from river bottom to atmosphere caused the decrease of TOC, AVS and pH and increase of ORP, and lowered the amount of extractable heavy metals. Heavy metals have the tendency to release to water body. The migration rates of Cu, Pb, Cd and Cr were 30.50%, 26.10%, 33.50%, and 11.77% respectively, the migration ability of heavy metals followed: Cd > Cu > Pb > Cr. The contributions of extractable fractions of Cu, Pb, Cd and Cr to the migrated heavy metals were 77.15%, 86.09%, 94.86%, and 32.34% respectively, extractable fraction was the mainly part of the migrated heavy metals. The off-season regulation model for Three Gorges Reservoir lowered the ecological harm of heavy metals, the concentrations of Cu, Pb, Cr, Cd in the study areas were low.

[Preliminary study on bacterial culture through near-natural pure culture technique].

Based on the ecological features of mutual benefits of different microbes in natural environment, near-natural pure culture technique which was an improvement of conventional pure culture method had been put forward. The key point of this new method was to make hole petri dishes covered with millipore membranes. When these covered dishes being used to culture microorganisms, it could provide incubated microbes active materials from native environment, maintain free communicating with outside microbes, and improve their recovery and culturability of some bacteria. To some degree, this technique enhanced their strengths and overcome their weaknesses of mixed culture method and conventional pure culture method so as to increase microbial culturability and even possibly obtain some nonculturable microorganisms.