浙江省东阳江干流水质分析与评价

Water Quality Analysis and Assessment of the Main Stream of Dongyang River

为研究东阳江污染物的分布特点以及10多年来的水质发展趋势，运用变权欧式距离模型对浙江省东阳江3个监测断面进行水质综合评价。根据污染贡献率计算污染因子的权重，并在此基础上对各断面进行单污染因子分析。根据评价结果分析东阳江综合水质以及污染因子的时间走向和空间分布。研究结果表明，除最上游以外，东阳江的水质状况有逐年恶化的趋势，尤其以下游最为明显；水质从上游到下游逐渐变差，上游水质最好，基本能达Ⅱ类水质标准，而下游的水质处于Ⅴ类，甚至劣Ⅴ类水平，污染非常严重，远不能满足水功能区用水要求：整个东阳江的主要污染因子为NH3-N、TN，且下游的NH3-N、TN浓度一直严重超标。分析了造成东阳江水质污染特点的原因，并给出了可供参考的建议。

Euclidean distance model with varying weights was applied to comprehensive assessment of water quality at three monitoring cross-sections of Dongyang River, Zhejiang Province. Weights were added to pollu- tion factors based on different pollution contribution ratios, whilst single pollution factor analysis of individual cross-sections was conducted thereof. According to results of the evaluation, the comprehensive water quality, temporal trends and spatial distribution of the pollution parameters were analysed. Except for the upmost reaches, the water quality of Dongyang River revealed a deteriorating tendency year by year, especially in the lower reaches. The water quality became gradually worsened along the river varying from the upper reaches in Category Ⅱ to the lower reaches in Category Ⅴ or even worse in very seriously polluted condition far from meeting the requirements for relevant water functional uses. Critical parameters for whole Dongyang River were ammonia-nitrogen and total nitrogen, which were always incompliant to the standard limits in the lower reaches. Finally, causes of the pollution problems of Dongyang River were analysed and some recommendations were given.