北运河水系底栖动物群落结构与水环境质量评价

Macroinvertebrates community structure and water quality assessment in the North Canal River Basin,Beijing,China

为全面了解北运河水系的底栖动物群落结构和水环境质量,于2015年5月对北运河水系33个样点的底栖动物和水体理化性质进行了调查,分别采用综合水质标识指数法和底栖动物BI指数法对北运河水系进行水质评价,并通过Kolmogorov-Smirnov检验判断正态性,用Pearson相关分析方法对两种评价结果进行比较和分析.结果表明:北运河水系共采集到底栖动物23种,隶属于3门4纲6目11科11属,以水生昆虫和软体动物为主,整个水系底栖动物群落结构单一;底栖动物BI指数法的评价结果显示,72%的采样点水质为中污染(Ⅳ)或重污染(Ⅴ);综合水质标识指数法的评价结果显示,超过57%的采样点水质为Ⅳ类及以下;根据K-S检验,两组评价得分均符合正态分布;Pearson相关分析显示两种评价结果呈显著正相关.两种评价结果总体上呈现出相同的趋势,均显示北运河水系整体水质状况较差,干流水质状况优于支流,上游水质状况优于下游,温榆河上游、坝河下游、通惠河上游和凉水河的水质状况较差,温榆河源头和坝河上游的水质状况较好.两种评价结果在个别点位存在一定差异,具体表现为基于水体理化因子的评价结果稍优于水质生物评价结果,造成这种差异的原因是两种评价方法在时空尺度上存在差异.针对城市化水平较高、人类活动干扰较强的北运河水系,同时采用这两种评价方法有助于全面了解其复杂的水环境质量.

Macroinvertebrates as a biological indicator of aquatic health condition plays an important role in the protection and management of water ecological environment. Macroinvertebrates and water quality were investigated on the basis of samples collected at 33 sampling sites in the North Canal River Basin in May 2015. The community structure of macroinvertebrates was analyzed. The comprehensive water quality identification index and Biotic Index of macroinvertebrates were used to assess the water quality in the North Canal River Basin. The results obtained by using these two methods were compared each other by using the Kolmogorov-Smirnov test and Pearson correlation analysis. In this study, a total of 23 species of macroinvertebrates belonging to 3 phylum, 4 class, 6 order, 11 family and 11 genera were identified in the North Canal River Basin, which mainly represented by aquatic insects and molluscs. The community structure of macroinvertebrates in the whole basin was simple. The result of Biotic Index showed that 72% of the sampling sites were moderately（Ⅳ） or seriously（Ⅴ） polluted and comprehensive water quality identification index showed that more than 57% of the sampling sites were worse than Class Ⅳ. The K-S test showed that the results were confirmed to normal distribution and Pearson correlation analysis exhibited that the results of these two methods had a significant positive correlation. The two results had the same tendency generally. Depending on the results, the water quality in the North Canal River Basin was poor. The main stream was better than the tributaries and the upstream was better than the downstream. The water quality in the upstream of the Wenyu River, the downstream of the Ba River, the upstream of the Tonghui River and the Liangshui River were poor while the headwater of the Wenyu River and the upstream of the Ba River were excellent. The result of comprehensive water quality identification index was a little better than that of Biotic Index. This was attributed to the reason that the two assessment methods focused on different spatial and temporal scales. In the North Canal River Basin with high urbanization level and strong human disturbance, the complex water ecological condition could be better understood with both assessment methods at the same time.