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The effects of Cr(III) and Cr(VI) species ( 2 2 7 Cr O − , 2 4CrO − and Cr 3＋ ) on the growth of Escherichia coli (E. coli) have been investigated in detail by microcalorimetry at 37 ℃. Parameters including the growth rate constant (k), inhibitory ratio (I), half-inhibitory concentration (IC 50 ), total heat output (Q total ), time of the maximum heat production (t log ) in the log phase have been obtained. The results showed that Cr(VI) and Cr(III) had the inhibition effect on the growth of E. coli in aquatic environment; however, the inhibitory ratio of Cr(III) to E. coli was smaller than that of Cr(VI). The k values of E. coli in the presence of Cr(VI) and at high concentrations of Cr(III) were decreased with increasing the concentrations of these chromium species. Among the three chromium species investigated, 2 2 7Cr O − was found to be the most poisonous species against E. coli with an IC 50 value of 35.52 µg•mL -1 . 4CrO − exhibited moderate toxicity on E. coli with an IC 50 of 50.24 µg•mL -1 , and Cr 3＋ had the lowest toxicity with an IC 50 of 84.30 µg•mL -1 . Microcalorimetry can provide a convenient, sensitive and reliable method to study the effect of various metal species on the growth of bacteria or other microorganisms.

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Photocatalytic degradation of bisphenol A in aqueous solution by UV-TiO2 was studied in self-made photocatalysis reactor. The results showed that BPA was degraded effectively in UV-TiO2 photocatalysis system, and the processe followed Langmuir-Hinshelwood kinetic model. When TiO2 was dosed at 1.0 g/L, air amount was 1.2 L/min, BPA initial concentration was 10 mg/L with pH=5.5, and irradiated by a 15 W low pressure mercury vapor discharge lamp, the removal rate of BPA was up to 97%, and BPA was completely removed in 80 min when pH≥9.5; The photocatalytic removal rate constant was strongly related to the above factors.

To compare the difference bacterial diversity between Jianghan plain and Datong basin. The high arsenic sediment samples in this study were collected from different depths of borehole. The bacterial diversity in high arsenic aquifer sediments was studied by 16S rDNA clone library. The dominant bacterial community included Burkholderiales, Pseudomonadales, and Enterobacteriales in Jianghan plain, and Burkholderiales,Enterobacteriales and Actinomycetales in Datong basin.