平原城市区设闸河流氮磷污染物入海通量研究

Study of nitrogen and phosphorus fluxes into the sea from sluice-controlled river in plain urban area

利用2013～2015年海河防潮闸断面逐日流量及离散的水质数据,基于LOADEST模型构建了TN、TP入海通量多元线性回归方程,对方程进行了评估验证,TN、TP模型的判定系数(R2)分别达到0. 917、0. 924,表明LOADEST模型适用于平原城市区设闸河流断面污染物入海通量的评估。评估结果表明,海河防潮闸断面TN、TP入海通量及水质表现出不同的变化特征。2013～2015年,TN浓度月均值变化范围3. 38～8. 33 mg/L,汛期(6～10月)浓度低于非汛期,TP浓度月均值变化范围0. 17～0. 88 mg/L,汛期浓度高于非汛期; TN年均入海通量2200 t/a,汛期占43. 7%,日均入海通量25. 8 t/d,非汛期日均入海通量是汛期的2倍; TP年均入海通量216 t/a,汛期占69. 3%,日均入海通量2. 5 t/d,汛期日均入海通量高于非汛期,9月份最高,4月份最低。研究结果可为实施陆海统筹的最大日污染负荷(TMDL)总量控制提供科学依据。

Based on the LOADEST model,the multivariate linear regression equations of the total nitrogen(TN) and total phosphorus(TP) fluxes were constructed by using the daily flow and discrete water quality data at the Haihe sluice in 2013-2015. The equations were evaluated and the determination coefficient (R2 ) of TN and TP models were 0. 917 and 0. 924 respectively,which proved the LOADEST model is suitable for the evaluation of the pollutant fluxes into the sea from the sluice-controlled river in the plain urban area. The assessment results also indicated that the fluxes and water quality of the TN and TP showed different variation characteristics. In 2013-2015,the average monthly concentration of the TN varied from 3. 38 ~8.33 mg/L,the concentration in the flood season (June-October) was lower than the non-flood season. The monthly average concentration of the TP was 0.17-0.88mg/L,and the concentration in the flood season was higher than the non-flood season. The annual average flux of the TN was 2200t,the flood season accounted for 43.7%; the daily average flux was 25.8 t,this value in the non-flood season was twice as in the flood season. The annual average flux of the TP was 216 t,the flux in the flood season accounted for 69.3%; the daily average flux was 2.5 t,this value in the flood season was normally higher than the non-flood season,the highest daily average value was in September,and the lowest value was in April. The results of this paper can provide a scientific basis for the total maximum daily loads (TMDL) control implemented for both land and sea.