永定河上游主要河流地表水水质时空变化特征

2022年冬奥会水质安全保障是目前永定河上游水环境保护的重要工作。通过对2013—2017年永定河上游张家口地区河流水质的长期监测,研究永定河上游张家口地区主要河流地表水水质时空变化及其主要污染物年通量。结果表明:(1)2017年永定河上游张家口地区洋河上游水质清洁,中下游水质中度污染;清水河上游水质清洁,下游水质轻度污染;桑干河水质清洁。(2)不同河流水质年际变化差异明显。其中,洋河上游年际变化较小,中下游水质趋于恶化;清水河和桑干河水质波动较小;全流域五年综合污染指数为0.82,对应水质级别为轻污染。(3)洋河和清水河水质季节变化明显,而桑干河水质季节变化不明显。洋河夏季水质较差,清水河上游春季水质劣于夏秋季。总磷和氟化物是永定河上游主要污染物,洋河是污染物主要贡献源,其中总磷贡献率为74%,氟化物贡献率为61%;且总磷是水污染主要的限制因子,一旦污染,治理十分困难,因此应引起相关部门的高度重视。

Spatiotemporal variations of surface water quality of main rivers in the upper reaches of Yongding River

Water quality improvement in the upper reaches of the Yongding River in Zhangjiakou city has become a most significant work for the water safety of the Winter Olympics in 2022. The spatiotemporal variations of surface water quality and the annual flux of main pollutants in the main rivers of Zhangjiakou were studied by the long-term monitoring in Zhangjiakou in the upper reaches of Yongding River from 2013 to 2017. Results showed that: (1) The water quality in the upper reaches of the Yanghe River in Zhangjiakou was good in 2017, while that in the middle and lower reaches was moderately polluted. The water quality in the upper reaches of the Qingshui River was good, while that of the lower reaches was slightly polluted. The water quality in the Sanggan River was good. (2) The differences between the water quality indexes in different rivers were obvious from 2013 to 2017. The variation of water quality in the upper reaches of the Yanghe River was small from 2013 to 2017, while the that of the middle and lower reaches tends to deteriorate. The fluctuations of water quality in the Qingshui and Sanggan rivers were small, and the five-year comprehensive pollution index of the whole basin was 0.82, corresponding to the level of light pollution. (3) The seasonal changes of water quality in the Yanghe and Qingshui rivers were obvious; however, those in the Sanggan River were not obvious. The water quality indexes of the Yanghe River were higher in summer than those in spring and autumn. And the water quality indexes in spring were higher than those in summer and autumn. Total phosphorus and fluoride are the main pollutants in the upper reaches of the Yongding River, with Yanghe River being the main source of contribution. Among them, the contribution rates of total phosphorus and fluoride are 74% and 61%, respectively. Therefore, the local government should focus more on the prevention of phosphorus pollution because the phosphorus was the main factor that can limit water pollution. Once the water is polluted by phosphorus, it will be very difficult to be remedied.