三峡库区古夫河小流域氮磷排放特征

本文以三峡库区古夫河小流域为研究对象,在自然降雨条件下,自2014年1月至2014年12月对古夫河小流域出水口断面水质水量进行了连续监测,分析了流域出水口断面污染物氮磷输出浓度、排放负荷随降雨的季节变化特征及其形态组成.结果表明,古夫河小流域年度水流量为0.6×108m3,7~9月丰水期径流量占全年的63.9%,流域出口径流流量与年降雨量间存在极显著(P0.01)的线性相关关系.小流域总氮的年排放负荷为1 432 t·a-1,溶解态氮是氮的主要排放形态,各月份溶解态氮排放负荷占总氮比例的变化范围为55.4%~91.3%,7~9月丰水期总氮排放负荷达853 t·a-1,占全年的59.6%;硝态氮输出浓度与降雨量间存在显著(P0.05)线性相关关系,其他形态氮浓度与降雨量、泥沙量间线性相关关系均不显著.总磷的年排放负荷为563.1 t·a-1,颗粒态是磷的主要排放形态,各月份颗粒态磷排放负荷占总磷比例的变化范围为41.9%~79.5%,丰水期总磷的排放负荷占全年的71.2%,总磷、可溶性总磷和颗粒态磷与降雨量和泥沙流失量之间均存在显著(P0.05)线性相关关系.

Characteristics of Nitrogen and Phosphorus Emissions in the Gufu River Small Watershed of the Three Georges Reservoir Area

To study the seasonal change characteristics and form composition of nitrogen and phosphorus output concentration and pollutant discharge load with rainfall characteristics at the outlet of Gufu river small watershed,the quality and quantity of water combined with natural rainfall events were monitored from January to December 2014.The results showed that the annual runoff volume of the Gufu river small watershed was 0.6×10⁸ m³.The runoff was concentrated in raining season (from July to September),accounting for 63.9%.There was significant (P<0.01) positive correlation between the runoff flow and the annual rainfall.The annual emission of total nitrogen (TN) was 1432 t·a^-1,and the emission was 853 t·a^-1 during the raining season,accounting for 59.6% of annual TN emission content.The dissolved nitrogen was the main form of nitrogen emission,and the emission load of each month accounted for 55.4%-91.3% of TN.The positive correlation between the nitrate nitrogen concentration and rainfall was significant (P<0.05).The annual emission of total phosphorus (TP) was 563.1 t·a^-1,and the content during the raining season accounted for 78.6% of TP annual emission content.The particle phosphorus (PP) was the main form of phosphorus emission,and the emission load of each month accounted for 41.9%-79.5% of TP.There was significant (P<0.01) positive correlation between the annual rainfall,sediment and TP,PP.The correlation between the total dissolved phosphorus concentration and rainfall was significant (P<0.05).