长江干流氮、磷浓度变化趋势分析

ANALYSIS OF VARIATION TREND OF NITROGEN AND PHOSPHORUS CONCENTRATIONS IN THE MAIN STREAM OF THE YANGTZE RIVER

基于长江干流宜宾、宜昌、汉口、大通和上海(石洞口)5个断面2004—2016年NH_3-N和TP浓度监测数据,采用spearman秩相关系数法探究长江干流氮、磷浓度的年际变化趋势和年内变化规律。结果表明:研究期间长江干流上游的NH_3-N浓度低于中下游,可达到GB 3838—2003《地面水环境质量标准》Ⅰ类水质标准,TP浓度在全河段浓度均较高,达到Ⅲ类水质标准;NH_3-N浓度在此期间具有显著下降趋势,而TP浓度呈显著上升趋势;上游NH_3-N浓度并不随流量变化,TP浓度与流量的年内分布呈正相关,中下游的NH_3-N和TP浓度与流量的年内分布均呈负相关。

Based on the ammonia nitrogen and total phosphorus concentration data of Yibin, Yichang, Hankou, Datong, and Shanghai(Shidongkou) sections in the main stream of the Yangtze River from 2004 to 2016, spearman rank correlation coefficient method was used to explore the inter-annual variation trend and intra-annual variation rule of nitrogen and phosphorus concentrations in the main stream of the Yangtze River. The results showed that during the study period, the concentration of ammonia nitrogen in the upper reaches was lower than that in the middle and lower reaches of the mainstream of the Yangtze River, which could meet the water quality standard of Class I, and the concentration of total phosphorus was higher in the whole river and reached the water quality standard of Class III;the concentration of ammonia nitrogen decreased significantly during this period, while the total phosphorus concentration showed a significant upward trend;upstream ammonia nitrogen concentration did not vary with the flow rate, and the total phosphorus concentration and the intra-annual distribution of the flow rate were in a positive correlation trend, while the ammonia nitrogen and total phosphorus in both the middle and lower reaches showed a negative correlation trend with the intra-annual distribution of the flow rate.