川贵地区长江干支流河水主要离子含量变化趋势及分析

Evolution trend and analysis of major ion contents in the mainstream and some tributaries of Yangtse River in Sichuan and Guizhou provinces.

收集整理了川贵境内长江干流及某些支流近３０年来河水主要离子含量资料，发现该地区河水主要离子含量有以下变化趋势：Ｃａ２＋、ＳＯ２－４含量及总硬度与总碱度的比值均有升高趋势，某些站点的ｐＨ值和ＨＣＯ－３含量还有下降趋势。通过对上述离子含量变化与当地酸沉降、氮肥施用量的关系分析，初步认为当地河水水质变化趋势是环境酸化过程在酸不敏感地区对陆地水水质影响的一种表现。

The data of major ion contents in the mainstream and some tributaries of Yangtse River in Sichuan and Guizhou provinces in recent 30 years were collected from Water Year Book. The analysis of water quality evolution trend has been carried out, and the results are summarized as follows: the contents of calcium and sulphate ions increase as well as the ratio of total hardness to alkalinity, and decrease of pH and alkalinity are found in some hydrometric stations. The correlation analyses between the evolution trend of major ion contents and acid deposition and fertilizer quantity in the area have been carried out;and it is proved that the evolution trend of water quality is a phenomenon caused by environmental acidification process in the area insensitive to acid. 