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The water quality rankings of 1861 sections are released, leading the three plac

发布时间:2019-05-29 10:40:46

Recently, for the first time, the surface water quality in China has been ranked.
According to the Ministry of Ecology and Environment, the cities ranked in this ranking are all cities at or above the prefecture level with the national surface water assessment section. In the water quality ranking, the sections covered are 2050 national surface water assessment sections set up by the National Surface Water Environmental Quality Monitoring Network Setting Plan of the 13th Five-Year Plan. On the contrary, it does not involve urban groundwater, black and odorous water bodies, and smaller rivers, lakes or reservoirs without national surface water assessment sections.

Previously issued "Water Pollution Prevention and Control Action Plan" made it clear that, taking into account the factors such as water environment quality and meeting the standards, the state publishes the list of the 10 worst and best cities and the water environment status of provinces (districts and municipalities) every year. In terms of specific calculation indicators, except water temperature, fecal coliform bacteria and total nitrogen, the assessment was weighted according to 21 indicators involved in the Standard for Surface Water Environmental Quality, which was consistent with surface water evaluation and assessment indicators.

Before that, in order to realize the real and accurate monitoring data, the Ministry of Ecology and Environment unified the surface water assessment sections of 2050 countries and implemented the separation of mining and measurement, which realized the decoupling of water quality monitoring and assessment objects from the operational mechanism. That is to say, sampling is carried out by a third party agency entrusted by the Ministry of Ecology and Environment, and testing is randomly assigned to nearby units with testing qualifications. In addition, the monitoring mode of "automatic monitoring as the main and manual monitoring as the supplement" is gradually expanding in the national surface water assessment section.

Consistent with the above premises, in the first quarter of 2019, more than 1900 national assessment sections have been fully covered by monitoring network through mining separation mode. During this period, about 1858 sections were actually monitored. In March alone, the proportion of section with good water quality (Class I-III) was 74.3%, up 5.8 percentage points from the same period last year, while the proportion of section with inferior Class V was 5.5%, down 3.1 percentage points from the same period last year. The main pollution indicators are total phosphorus, chemical oxygen demand and ammonia nitrogen.