长江干流2010~2019年主要污染物时空变化分析

Analysis of Temporal and Spatial Variation of Main Pollutants in the Main Stream of the Yangtze River from 2010 to 2019

为明晰长江干流主要污染物浓度的时空变化趋势,选取长江干流23个监测站点2010~2019年逐月常规水质数据,采用单因子评价法、线性趋势分析法分析研究了典型耗氧指标(高锰酸盐指数和五日生化需氧量)、典型营养盐指标(氨氮和总磷)、典型重金属指标(砷)的空间变化情况。结果表明,高锰酸盐指数和五日生化需氧量浓度水平低,氨氮和总磷浓度相对较高,砷浓度优于地表水Ⅰ类水质标准;空间变化呈现出浓度沿程增加趋势,时间变化呈现出浓度降低趋势;人类活动对长江污染物的作用明显,人口和经济集中区域污染物浓度较高。在2010~2019年人口增加、经济总量翻倍的条件下,流域污水入河量变化不大,且水质趋于好转,说明长江流域高质量发展取得初步成效。

In order to clarify the temporal and spatial variation trend of the concentration of main pollutants in the main stream of the Yangtze River from 2010 to 2019, factor evaluation method and linear trend method were used to analyze the spatial variation of indexes including typical oxygen consumption(permanganate index and five-days biochemical oxygen demand), typical nutrient(ammonia-nitrogen, total phosphorus), typical heavy metal(arsenic) based on the monthly water quality monitoring data in 23 stations. The results show that the permanganate index and the concentration of five-day biochemical oxygen demand are low, the concentration of ammonia nitrogen and total phosphorus are relatively high, and the concentration of arsenic is better than the class I water quality standard of surface water. The spatial variation shows an increasing trend of concentration along the distance process, and the temporal variation shows a decreasing trend of concentration. The effect of human activities on pollutants in the Yangtze River is obvious, and the concentration of pollutants in areas with concentrated population and economy is relatively high. However, with the increase of population and the doubling of total economic output from 2010 to 2019, the amount of sewage into the river has changed little, and the water quality tends to be improved, which indicates that the high-quality development of the Yangtze River Basin has achieved preliminary results.