渭河陕西段主要监控断面水质变化趋势分析

Water Quality Trend Analysis of the Main Control Sections of Wei River Reaches in Shaanxi Province

根据2000—2008年渭河陕西段13个水质监控断面的监测资料,采用图解法和季节性Kendall检验法,对COD、NH3-N的浓度变化趋势进行分析,结果表明:渭河自林家村断面以后水质污染情况明显加重,直至潼关吊桥断面(渭河陕西省出省断面)COD、NH3-N的监测浓度仍然超过《地表水环境质量标准》(GB3838-2002)Ⅴ类标准限值要求;从空间变化情况看,COD监测浓度自咸阳市兴平断面明显增加,沿渭河流向总体呈现上升趋势;从时间变化情况看,渭河陕西段水质总体呈现好转的趋势,这可能与入河污染物总量的变化有关。

Changes of the concentrations of COD and NH3-N from the main sections of the Wei River reaches in Shaanxi Province were discussed by employing the graphic method and the method of seasonal Kendall test in terms of the data collected over the period from 2000 to 2008.Conclusions can be drawn from the results：（1） The pollution status is more severe in the reaches after Linjiacun control section,and the concentrations of COD and NH3-N exceed The National Surface Water Quality Standards;（2） the concentration of COD in the reaches after Xingping control section in Xianyang City has the upward trend of the concentration of COD in the reaches along Wei River;and（3）the water quality of the Wei River reaches tends to become better,which is possibly the result of the change of the amount of pollutants entering the river.