珠江(广州河段)表层沉积物中营养物质的分布特征及肥力评价

Distribution characteristics and fertility assessment of nutrients in surface sediment in Guangzhou section of Pearl River

随着广州市截污工程的实施,珠江(广州河段)外源污染得到有效控制后,沉积物内源污染将成为影响河流水质的重要因素。本文在珠江(广州河段)表层沉积物中TN、TP和有机质质量分数监测的基础上,对该河段沉积物中三种营养物质的空间分布特征进行了全面的分析,并对它们之间的相关性及沉积物的肥力状况进行了研究。结果表明:在主干流河道沿程分布上,各种营养物质整体上表现出明显的"低-高-低"型分布特点。三种营养物质之间均呈现较明显的正相关关系,特别是TN和有机质之间的相关系数达到0.950,属于高度相关,其线性方程为:y=0.0387x+0.0068(y为TN,x为有机质)。有机指数法对沉积物肥力状况的评价结果表明,珠江(广州河段)全河段有机指数相当高,全河段都处于肥污染状态。沉积物中C/N值表明该河段中有机质及营养盐除少量来自河中藻类、浮游动物与浮游植物等外,多数来源于周围环境。

The internal pollution sources are going to be the main factors to influence the water quality of river, with the implementation of interception project, which has effective control of exotic pollution sources in Guangzhou section of the Pearl River. Based on the monitoring results of TN, TP and organic content in the surface sediments, a systematic study was carried out on the spatial distribution characteristics of nutrients, the correlations among nutrients and the fertility in the surface sediments in Guangzhou section of the Pearl River. The results show that each nutrient appears the distribution characteristics of ＂low-high-low＂ on longitudinal distribution in trunk stream on whole. There is a significant and positive correlation among nutrients, especially between TN and organic content. The linear equation between TN and organic content is y =0. 0387x ＋ 0. 0068（ y：TN ;x：organic content）with 0. 950 of correlation coefficient. The results of fertility assessment show that the organic index in the whole Guangzhou Section is higher than standard level of fertility in sediment. The C/N ratio in the surface sediments show that most of organic content and nutrients are from the near surroundings, only a little of them are from the algae, zooplankton and phytoplankton et al. in the river.