苕溪污染物入湖通量研究

Research on pollutant discharge loads from Tiaoxi to Taihu

根据2005～2010年苕溪入湖河流小梅港、长兜港和大钱港的水质监测资料以及杨家埠和杭长桥2个水文基点站的径流量数据,计算CODMn、NH3-N、TP和TN等污染物的入湖通量来明确苕溪入湖的主要污染及通量的关键影响因子.采用单因子指数法进行水质评价并计算水质的污染分担率,表明苕溪的入湖河流水质总体为Ⅲ类,首要污染物为TN;统计逐日流量数据,计算2005～2010年入湖水量为9.15×108～17.85×108 m3;对污染物年通量进行等标计算,发现总氮的等标入湖量最高,年均入湖通量为3 415t;对水质、水量与通量进行相关性分析,水量与通量的相关系数远高于水质,且两者之间呈现季节性响应关系.因此,总氮是苕溪入湖的主要污染,水量是通量的关键影响因子.

Tiaoxi is one of the main inflow rivers around Taihu. Based on the monitoring data on the water quality of three main rivers round Taihu Lake（ Xiao-mei Gang, Chang-dou Gang and Da-qian Gang） and on the water quantity of two staff gauge stations of Tiaoxi （ Yang-jia Bu and Hang-chang Qiao） during 2005～2010, Tiaoxi inflow rivers’ pollutant fluxes of CODMn ,NH3-N,TP and TN were calculated to find out the main pollutant from Tiaoxi to Taihu as well as the key factor of Tiaoxi‘s pollutant discharge loads. Single factor index method was used in water quality evaluation and the share rate of pollutant water quality indexes was calculated, the results showed that the water standard of each river was Class Ⅲ and the chief contaminant was TN. The water quantity from Tiaoxi to Taihu Lake during 2005～2010 was 9.15 X 10^8-17.85 X 10^8 m^3 by daily runoff statistics. The annual pollutant fluxes were standardised equivalent calculated that the equal standard value of TN was highest, whose average pollutant flux was 3 415 t. In addition, the correlation between water quality, water quantity and pollutant load was analyzed that the related coefficient between water quantity and pollutant load was much higher than which between water quality and pollutant load. Furthermore, the pollutant fluxes of Tiaoxi had seasonal response relation to the water quantity. Consequently, total nitrogen was the main pollutant index in Tiaoxi inflowing rivers and the water yield was the key- influencing factor of pollutant discharge load.