Rapid automated in-situ monitoring of total dissolved iron and total dissolved manganese in underground water by reverse-flow injection with chemiluminescence detection during the process of water treatment

Measurement of iron and manganese is very important in evaluating the quality of natural waters. We have constructed an automated Fe(II), total dissolved iron(TDI), Mn(II), and total dissolved manganese(TDM) analysis system for the quality control of underground drinking water by reverse flow injection analysis and chemiluminescence detection(rFIA-CL), The method is based on the measurement of the metal-catalyzed light emission from luminol oxidation by potassium periodate. The typical signal is a narrow peak, in which the height is proportional to light emitted and hence to the concentration of metal ions. The detection limits were 3 x 10(-6) mu g ml(-1) for Fe(II) and the linear range extents up to 1.0 x 10(-4) and 5 x 10(-6) mu g ml(-1) for Mn(II) cover a linear range to 1.0 x 10(-4) mu g ml(-1). This method was used for automated in-situ monitoring of total dissolved iron and total dissolved in underground water during water treatment. (C) 1997 Elsevier Science B.V.

Effects of Fracture Seepage on the Stability of Landslide during Reservoir Water Level Fluctuation

The hydraulic conductivity function of fractures is a key scientific question to describe and reveal the process and the role of water seepage reasonably. In this paper, the generation technology of random fracture network and the latest numerical computation method for equivalent permeability tensor of fracture network are applied to analyze the landslide located at Wangjiayuanzi in Wanzhou District of Chongqing by simulating the changes of the seepage field caused by the running of the Three Gorges Reservoir. The influences of the fracture seepage on the seepage field and stability of the landslide were discussed with emphasis. The results show that the fractures existing in the soil increase the permeability coefficient of the landslide body and reduce the delay time of the underground water level in the landslide which fluctuates relative to the water level of reservoir，that causes the safe coefficient of the slope changes more gently than that of the same slope without fractures. It means, if only water level fluctuating condition is concerned, the fractures existing in the soil plays a positive role to the stability of slopes.