沣河水污染特征及非点源污染负荷估算分析

沣河流域的主要污染指标为COD、BOD5、NH4+-N等,非点源污染负荷的定量化对流域水污染控制和水环境综合治理意义重大。结合沣河1986-2009年水量、含沙量及水质状况监测数据进行有机污染综合指数及相关分析,并采用平均浓度法对流域的非点源污染负荷和点源污染负荷进行了研究。结果表明:(1)有机污染综合指数(A值)呈抛物线趋势,径流量与沣河水质呈负相关性,含沙量与沣河水质呈正相关性。通过产业结构调整等措施,近年来沣河水质有明显改善;(2)沣河的污染负荷大部分来自降雨径流引起的非点源污染,在沣河水污染中TN的非点源污染负荷比例在56%以上,TP的非点源污染负荷比例在68%以上,NH4+-N的非点源污染负荷比例在63%以上,比重较大,非点源污染对沣河水质的影响不容忽视,而且TP受到的影响相对最大,可通过合理配置水土保持措施,有效防治非点源污染。

Estimation of Variation Tendency of Water Pollution and Non-point Source Pollution Load in the Fenghe River

The main organic pollutant indexes of the Fenghe river are COD,BOD5 and NH+4-N.Estimation of non-point source pollution load is great important in the water pollution control and water environment management for the Fenghe river.On the basis of water quantity,sediment concentration and water quality monitoring data of 1986-2009,the annual organic pollution index and the variation of tendency of water pollution in the Fenghe river were analyzed,and the non-point source pollution load was estimated using mean concentration method.The results can be concluded as:(1)The organic pollution index(A) showed the parabolic trend,annual runoff had negative correlation with Fenghe water quality,while sediment concentration had positive correlation with Fenghe water quality.Through industrial structure adjustment,water quality had been getting better in recent years.(2)Major part of non-point source pollution load of the Fenghe resulted from flood induced by rainfall.The ratios of TN,TP and NH+4-N from non-point source pollution to the total pollution were above 56%,68% and 63%,respectively.Therefore,the non-point source pollution should be paid great attention,and some effective measures such as water and soil conservation should be put into effect in order to control non-point source pollution.