泥沙沉降对水体中溶解性有机物光谱学特性的影响

以沈阳市新开河为研究对象,考察了泥沙沉降过程中,沉降时间、泥沙含量、pH、盐度对水体中溶解性有机物(DOM)的含量和光谱学特性的影响.结果表明,泥沙沉降条件下,水体中DOC随泥沙沉降时间的增长而先增大后减小,随泥沙含量的增加而先减小后增大,随pH的增大而增大,随盐度的增大而减小.随着pH的增大,水体中DOM的芳香性增强;随着盐度的增大,水体中DOM的芳香性降低.随着泥沙沉降时间的增长,DOM中各类荧光物质的含量先增加后减少;随着泥沙含量的增加,DOM中类腐殖酸和类富里酸荧光物质的含量增加,而类溶解性微生物代谢产物荧光物质和类芳香族蛋白质荧光物质的含量降低.在泥沙沉降过程中,下层水体中DOC、在波长为254 nm处的紫外吸光度(UV-254),以及DOM中荧光物质含量的变化量高于上层水体.

Effect of sediment subsiding on the spectroscopic characteristics of dissolved organic matter in waters

The effect of settling time, sediment concentration, pH and salinity on the content and spectroscopy characteristics of dissolved organic matter (DOM) in the Xinkaihe River water in the process of sediment deposition was investigated. The results showed that, during the sediment deposition, dissolved organic carbon (DOC) in waters initially increased and then decreased with the increase of sediment deposition time; DOC initially decreased and then increased with the increase of sediment contents; DOC increased with the increase of pH, and decreased with the increase of salinity. The aromaticity of DOM increased with the increase of pH and decreased with the increase of salinity. The contents of all types of fluorescent materials in DOM initially increased and then decreased with the increase of sediment deposition time. The contents of fulvic acid- and humic acid-like fluorescent materials in DOM increased and those of aromatic protein- and soluble microbial byproduct- like fluorescent materials in DOM decreased with the increase of sediment contents. In the process of sediment deposition, the changes in DOC, the absorbance of ultraviolet light at 254 nm (UV-254), and contents of fluorescent materials in DOM in the lower water body was greater than those in the upper layer.