| 1 | Geochemical baselines of major,minor and trace elements in the tropical sediments of the Terengganu River basin,Malaysia显示文摘The geochemical baselines and distribution of 31 elements (Al, Fe, K, Na, Mg, Ca, Mn, Ba, Cr, Zr, Ni, Sr, Zn, Y, Li, Cu, Mo, Nb, Th, Co, Ga, W, Ta, Be, Ti, Ge, Se, Bi, Te, Sc and Re) and physico-chemical parameters of the tropical surface sediments of the Terengganu River basin, Malaysia, are reported. Sediments are sandy loam to sand in texture consisting of mostly quartz, low organic matter content (average-2.68%), low CEC (average-2.02 cmol(+)/kg) and mildly acidic pH1:5 (average-5.91). Concentrations of Mn, Fe, Ba, Cr, Ni, Cu, Mo and Se were measured to be above the environmental sediment quality criteria at various locations. Lake sediments registered significantly higher Al, Fe, Ti, Mg, Ca, Mn, Te and Sc concentrations as compared to the river sediments. Most of the elements investigated showed an association with silt size fraction (2-63 μm). Among the investigated metals, Mo and Fe concentrations showed an increasing (>5-fold) and decreasing (>3-fold) trend, respectively, along the river path from the upstream to the downstream depending on the stream pH-redox conditions. The enrichment factor values (EF >5) of Cr, Ni, Mo and Se indicated enrichment from anthropogenic activities. Alkali and alkali earth metals registered a significant depletion (EF values <0.7) as compared to the Earth's crust. Principal component analysis of the two main components (PC1, 87.4% and PC2, 8.7%) revealed a well-defined group of estuary sediments. Lake and river sediment sampling locations did not form defined groups revealing heterogeneity in the origin of geologic material and the in-stream geochemical processes. However, Cr, Ni, Mo and Se formed a separate group with elevated concentrations (e.g. Cr>1,000 mg/kg) indicating contamination of sediments. This work presents the geochemical baselines of the tropical sediments as industrial development and urbanization along the north east coast of Peninsular Malaysia are advancing rapidly. | Khawar SULTAN Noor Azhar SHAZILI | 2010 | International Journal of Sediment Research2010，25，4： | 3 |
| 2 | Experimental study on desorption of soluble matter as influenced by cations in static water显示文摘With variation of drainage basin environments, desorption of soluble matter has become one of the significant erosion processes in rivers. It has a considerable impact on flow and sediment transport, as well as processes of river bed deformation and landform evolution throughout a watershed. In this study, considering influences on sediment movement, especially on cohesive sediment transport, Ca2+ and H+ were chosen as characteristic ions of soluble matter, and the total desorption quantity of Ca2+ and pH value when the desorption equilibrium is reached were employed as two indexes representing the desorption of soluble matter. By means of an indoor experiment, desorption of soluble matter as influenced by cations in static water was investigated. The results show that the total desorption quantity of soluble matter increases with the initial cation concentration until a maximum desorption quantity value is obtained and maintained. The total desorption quantity of soluble matter depends on properties of the specific cations in static water, and the stronger the affinity is between the cation and sediment surface, the higher the total desorption quantity will be. Finally, a strong approximate linear relationship between desorption quantities for different kinds of soluble matters was obtained, which means that variation of pH values can accurately reflect the desorption results of soluble matter. | Wen-sheng XU Li CHEN Xiao-xia TONG Xiao-ping CHEN Ping-cang ZHANG | 2014 | Water Science and Engineering2014，7，4： | 0 |
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