中文摘要：

利用定点监测的方法对三峡库区2个小流域水体中可溶性硅（DSi）、可溶性无机氮（DIN）和可溶性磷（DP）含量及其变化规律进行了研究,分析了三者之间的比例关系及可能引起的环境问题。结果表明,2006年宝塔河流域和曲溪流域DSi含量在0.18-19.89mg·L^-1之间,DIN含量在0.39-6.85mg·L^-1之间,枯水季节含量高于丰水季节；DP含量在0.01-0.08mg·L^-1之间,无明显的季节性变化。曲溪流域水体中DSi、DIN的含量明显高于宝塔河,这可能与当地的农户活动、土地利用类型、施肥量等因素有关；而DP含量在两流域间无明显差异,具体影响因素还有待探索。两流域水体中DSi、DIN含量均高于库区水体,DP含量低于库区。宝塔河流域水体中的DSi、DIN和DP的含量比例为138∶81∶1,而曲溪流域为500∶350∶1,从水体营养学角度来看,两流域营养物质含量比均达到发生“水华”现象的程度,其水环境问题的潜在威胁值得关注。

英文摘要：

By using the method of fixed-pointed monitoring in streams of two small watersheds in Three Gorges Reservoir Area, the contents of dissolved silicon （DSi）, dissolved inorganic nitrogen （DIN） and dissolved phosphorus （DP） are analyzed. The seasonal variation, the content ratio of DSi, DIN and DP, and the potential environmental problems are also discussed. The results indicate that： ①In the two rivers, DSi content ranges from 0.18 to 19.89 mg· L^-1 , DIN from O. 39 to 6.85 mg·L^-1, and both are higher in the dry period than in the wet period;②DP content is from 0.01 to 0.08 mg·L^-L, which shows no significant difference between the dry and wet period;③The contents of DSi and DIN in Quxi River are higher than in Baota River, which may relate with the local agricultural activities, land use/land cover, fertilizer and so on;④The contents of DSi, DIN and DP in two small watersheds are all higher than in Three Gorge Reservoir, and the content ratio of DSi, DIN, DP is about 138：81：1 in Baota River, and 500：350：1 in Quxi River, which suggests that more attention should be paid to a potential threat to water environment such as Water-bloom.