环太湖江苏段入湖河道污染物通量与湖区水质的响应关系

基于2008-2018年环太湖江苏段入湖河道污染物通量及湖区水质数据,从时空变化及相关关系两个方面探讨了入湖污染物通量与湖区水质的响应关系,并分析了污染物进入湖体影响水质的主要因子.结果表明:太湖污染减排已见成效,氨氮、总氮、高锰酸盐指数和化学需氧量入湖污染物通量整体呈下降趋势,年均下降率分别为8.0%、2.0%、1.6%和2.2%,湖体氨氮和总氮时间格局响应较好,年均下降率分别为2.1%和2.3%.湖体氨氮、总氮、总磷、高锰酸盐指数和化学需氧量与入湖污染物通量整体由西北部、西部湖区向东南部、东部湖区递减,空间格局上响应基本一致.全湖区年尺度总氮、氨氮浓度与入湖河道污染物通量分别呈显著正相关、极显著正相关关系;影响湖区总氮、氨氮的主要因子为入湖河道的总氮、氨氮浓度,其次为入湖河道浓度与原湖区水质差值,因此亟需加强入湖河道水质浓度的控制.

Relationship between water quality in Lake Taihu and pollutant fluxes of the rivers surrounding Lake Taihu in Jiangsu Province

Based on pollutant fluxes of the rivers surrounding Lake Taihu in Jiangsu Province and water quality in Lake Taihu, the response relationship between pollutant fluxes of the rivers and water quality in lake was studied from two aspects of temporal and spatial variation and correlation, main factors that affected water quality were analysed after pollutants discharged into lake. The results showed that the temporal distribution of total nitrogen (TN) and ammonia nitrogen (NH₃-N) concentrations in Lake Taihu were in good accordance with distribution of TN and NH₃-N fluxes in river channels. TN and NH₃-N concentrations in the lake declined since 2008, with the decrease rate per year of 2.1% and 2.3%, respectively. The year descending rates of annual influxes of NH₃-N, TN, COD_Mn and COD_Cr were 8.0%, 2.0%, 1.6% and 2.2%, respectively. TN and NH₃-N concentrations in Lake Taihu and their fluxes in river channels were positively significantly correlated. NH₃-N, TN, TP, COD_Mn and COD_Cr in the western and northwest areas were better than that in the centre, southern and eastern areas, corresponding to pollutant fluxes of the rivers. Analysis of collinearity diagnosis and multiple stepwise regression indicated that TN, NH₃-N concentrations in river channels,and difference values of TN, NH₃-N concentrations between river and lake were significantly related with water quality in the Lake Taihu. It''s desiderated to strengthen the control of river water quality.