新建人工深水湖泊沉积物上覆水和孔隙水中溶解性有机质的光谱特征

摘要

为了揭示湖库内源性污染物的分布、来源、组成及垂向分布特征,以新建人工深水湖泊龙景湖为研究对象,采用紫外-可见光谱和三维荧光光谱技术,研究了该湖泊以成湖前用途划分的3个特征区域(原河道底部、新淹没区底部和新淹没区边坡)的沉积物上覆水和孔隙水中的溶解性有机质(DOM)的光谱特征.结果表明,孔隙水中的DOM芳香性和腐殖化程度高于上覆水;孔隙水中疏水组分含量大于上覆水,且水体中可能存在内源孔隙水释放的低分子量DOM.龙景湖上覆水和孔隙水中的DOM主要源于水体自身的微生物,自生源特征明显,且可能存在新近释放到水体的有机质.龙景湖沉积物上覆水和孔隙水中的DOM以类腐殖酸和类蛋白质为主,且随着深度增加,类腐殖酸峰强度增强,与龙景湖的建湖背景有明显联系.%In order to reveal the sources,compositions,distributions and vertical distribution characteristics of endogenous poilutants in lake sediments,the ultraviolet-visible spectroscopy and three-dimensional fluorescence spectrum technology were applied to study the spectral characteristics.Data used in this work including sediment samples collected from the original riverbed,the newly submerged bottom and the newly submerged edge along the lakeside from the newly-built artificial deep-water lake,Lake Longjing.The divisive criterion of sampling sites is the main applications of those lands before impoundment.Results show that the aromaticity and humification of dissolved organic matter (DOM) in pore water is higher than those of overlying water.The proportion of hydrophobic components in pore water is greater than that in overlying water,which means there might be internal input of low molecular weight DOM.Data indicates that DOM of each sample mainly come from aquatic microbial activity within the water body and newlyreleased organic matter might exist.DOM of overlying water and pore water in Lake Longjing sediments mainly include humic-like parts and protein-like parts with humic-like peaks detected in the deeper layers,which indicates a significant association with the construction background of Lake Longjing.