黄河主要水系水环境与底栖动物调查研究

Survey of water quality and benthos in the Yellow River Basin

2005年5月对黄河水系的42个采样点进行了水质与底栖动物的调查研究。调查结果表明，黄河水质总体污染严重，干流兰州段以上相对较好，但下游及支流水质污染严重。主要污染指标为总氮超标。在这些样点上共采到底栖动物90种，分属5门23科60属。其中，水生昆虫67种（74．4％），寡毛类15种（16．7％），软体动物5种（5．6％），甲壳动物与线形动物各一种（2．2％）。物种组成上水生昆虫的摇蚊幼虫和寡毛类的水丝蚓为主要类群。在数量分布上，全流域底栖动物的平均密度为411．1ind·m2。，生物量为1520．1mg·m2。干流密度与生物量（144．3ind·m2和151．6mg·m-2）相对支流（1173．5ind·m-2和5430．1mg·m-2）明显偏低。与1958年和1982年的资料相比，所获得的物种数相近，但组成上有很大变化：而在密度生物量上，这次调查结果相对较低。

In May 2005, we surveyed water quality and benthos of the Yellow River basin in 42 sites. The results show that water quality of most part of the Yellow River basin is seriously contaminated, especially the index of total nitrogen. The main stem up Lanzhou is lightly polluted compare to stem down Lanzhou and tributaries. In these sites, we collected 90 taxa totally, which belong to 60 genera in 23 families in five phyla. Among them, there are 67 aquatic insects （74.4%）, 15 oligochaetes （16.7%）, five mollusks （5.6%）, one crustacean （2.2%） and one nematode （2.2%）.The main components of benthos are Chironomus and Oligochaeta groups. Average density and biomass in the Yellow River basin are 411.1 ind.m2 and 1520.1 mgom-2. The density and biomass in the main stem are obviously lower than the tributaries. Compare to the data from 1958 and 1982, the taxa number is almost similar, but the composition varies greatly and the density and biomass are comparatively lower in this survey.