渭河干流陕西段水体中CODMn,NH3-N的时空变化特征

渭河是陕西省的第一大河,然而近年来渭河水体污染严重,阻碍了区域经济的发展。依据1991—2002年渭河水质监测资料,对渭河干流陕西段水质主要污染指标CODMn,NH3-N的时空变化特征及其产生的原因进行了分析研究。(1)渭河陕西段污染严重,其中咸阳铁路桥为CODMn污染最严重的断面;卧龙寺桥、虢镇桥、兴平是NH3-N污染较严重的断面。(2)从90年代以来该流域的污染呈加重的趋势。1996年NH3-N污染最为严重,1995年CODMn最高。(3)造纸企业排放的污水是造成渭河流域CODMn污染的主要污染源;农田大量化肥的施用以及化肥工业废水的排放是造成渭河NH3-N污染的主要原因。

Temporal and Spatial Characteristics of Variation in COD_(Mn) and NH_3-N in Weihe River of Shaanxi Province

The Weihe River is the greatest river in Shaanxi Province.Its water pollution becomes very serious in recent years and has restricted the development of local economy.The temporal and spatial characteristics of variation in the pollution indexes of COD_(Mn) and NH_3-N,and the reasons for the variation were analyzed based on the data of water quality observed from 1991 to 2002.Results show that the Weihe River has been polluted seriously,in which the most serious COD_(Mn) pollution was observed at the Xianyang Railway Bridge,and the serious NH_3-N pollution was also observed at the Wolongsi Bridge,the Guozhen Bridge and Xingping City.Pollution of the river has become more and more serious since 1990's,with the highest value of NH_3-N observed in 1996 and the highest value of COD_(Mn),in 1995.The polluted water from paper mills is the main source of COD_(Mn) pollution,and chemicals applied on farmland and the discharge of waste water by fertilizer industries is the main reason for NH_3-N pollution.