中文摘要：

于2006年4月-2007年3月调查了西苕溪中上游3个参照、7个农业面源、3个小城镇和1个城市废水污染溪流的水质和底栖动物．结果表明，受污染溪流的NH3-N、TP、CODMn和电导率显著高于参照（P〈0．05）．城市溪流的NH3-N[（2．46±2．69）mg／L]、TP[（0．573±0．179）mg／L]和CODMn[（4．680±0．959）mg／L]显著高于农业面源和小城镇废水的（P〈0．05），但pH（7．34±0．06）和DO[（4．47±0．88）mg／L]显著低于农业面源和小城镇的（尸〈0．05）．小城镇污染溪流的TP和电导率显著高于农业面源的，其余指标均无显著差异．与参照相比，3种污染类型溪流底栖动物群落总分类单元丰富度、EPT丰富度、Shannon-wiener多样性指数和B-IBI生物完整性指数均显著降低．城市对底栖动物群落的影响最严重，但小城镇与农业面源之间对底栖动物群落结构的影响无显著差异．研究结果表明，农业生产废水和城镇废水污染是西苕溪中上游水生态系统健康退化的主要原因之一，但有关退化的机制还需深入研究．

英文摘要：

The pollution status of the Xitiao Stream and its benthic macroinvertebrates by the wastewaters from agricultural production, three towns and one city was investigated in a period from April 2006 to March 2007 in the middle and upper reaches of the Stream in Anji County, Zhejiang, China. The results showed that the ammonia （NH3-N）, total phosphorus （TP）, chemical oxygen demand （CODMn） and conductivity were significantly higher in the polluted streams than in CK stream （P〈0.05）. The NH3-N [（2.46±2.69） mg/L], TP [（0.573±0.179） mg/L] and CODMn [（4.680±0.959） mg/L] in the polluted stream by city wastewater were significantly higher than by agricultural production and town wastewaters, while pH （7.34±0.06） and DO [（4.47±0.88） mg/L] were significantly lower （P〈0.05）. TP and conductivity in the polluted streams by the wastewater from towns were significantly higher than by that from agricultural production, while other indicators had no significant difference. The total taxa richness, EPT taxa richness, Shannon-Wiener species diversity index and benthic index of biotic integrity （B-IBI） of the benthic macroinvertebrate community significantly decreased in the polluted stream compared with those in the CK stream （P〈0.05）. The influence of city wastewater on benthic macroinvertebrate community was the greatest. However, the influence of the wastewaters from agricultural production and towns on benthic macroinvertebrate showed no significant difference. These results suggested that the wastewaters from agricultural production, towns and city might be a major factor affecting the ecosystem of the upper Xitiao Stream.