2001-2002水文年环太湖河道的水量及污染物通量

Water Quantity and Pollutant Fluxes of the Surrounding Rivers of Lake Taihu during the Hydrological Year of 2001 -2002

根据2001-2002水文年115条环太湖河道的同步环境监测资料,对水量及污染物通量进行了估算.全年的入湖水量为80.11×108m3,出湖水量为96.67×108m3.入湖水量主要通过西部河网以及西苕溪、望虞河等河流汇入太湖,其中西部河网的入湖量占总入湖量的60%;出湖水量主要通过太浦河、东苕溪以及东部河网汇出太湖,其中太浦河的出湖量占47%.污染物通量的估算结果是,CODMn、TN及TP的入湖总通量分别为37571t/a、28658t/a及1029t/a,出湖总通量分别为35431t/a、14600t/a及668t/a.CODMn、TN及TP入湖通量通过西部河网进入太湖的比例占63%、49%及47%;CODMn、TN及TP出湖通量通过太浦河汇出太湖的比例占51%、45%及34%.通过与上世纪90年代以前相同年型的数据进行对比,除TP外,其它各种污染物的入湖量均明显增加,且污染物在湖泊中的滞留率也显著提高.由此说明,环太湖河道入湖污染负荷的增加是太湖水环境恶化的根本原因.

Based on the synchronous environmental monitoring of 115 surrounding rivers of the Lake Taihu during the hydrological year of 2001-2002,the water quantity and pollutant fluxes of these rivers were analyzed. In the whole hydrological year,total inflowing water was 8.01 billions m^3 , and total outflowing water was 9.67 billions m^3. The water entering the lake was mainly from the western rivers, occupying about 60% of the total incoming runoff, and water leaving the lake mainly went through the Taipu River, which discharged about 47% the total volume. The estimation of pollutant fluxes were that, inflowing fluxes of CODMn, TN and TP were 37571 t/a, 28658 t/a and 1029 t/a respectively,of which about 63% CODMn, 49% TN and 47% TP were come from western rivers, and outflowing fluxes of CODMn .TN and TP were 35431 t/a, 14600 t/a and 668 t/a respectively, of which about 51% CODMn, 45% TN and 34% TP were discharged from the Taipu River. In comparison with monitoring data before 1990, except TP, the inflowing fluxes of all other pollutants increased remarkably, and as a result the retention rate of the pollutants also increased observably. It is indicated that the deterioration of the water quality of the Taihu lake was mainly caused by the increasing of inflowing pollutant loads.