渭河中下游及主要支流氮素沿程变化与来源

Source and variation of nitrogen along middle and down stream of Weihe River and its main tributaries

渭河作为黄河的第一大支流正面临日益严重的人类活动的影响。本研究以渭河中下游为研究区,探讨干流和主要支流水化学特征及硝态氮(NO3--N)和铵态氮(NH4+-N)污染状况、沿程变化和可能影响因子。研究结果表明:渭河中下游及其支流水质以铵态氮超标为主。人类活动的影响已经广泛波及流域内干流和支流,部分采样点结果已经接近饮用水标准临界值。对NH4+-N而言,中游和支流流域应以防止点源污染为主,而下游则需全面加强环境保护工作,特别是污水排放的管理。对NO3--N而言,宝鸡和渭南的下游方向将是重点防范区,而支流的水肥合理利用应全面推广。

As the biggest tributary of the Yellow River,the Weihe River was confronting more and more serious effects from human being activities.The purpose was to explore the variety of NO-3-N and NH＋4-N along the Weihe River and possible factors affecting them.It can be characterized by the results that the water pollution along the middle and down stream and its tributaries of Weihe River was mainly exceed by NH＋4-N,part sampling sites were nearly close to the critical value of the safe drinking water standard.As to the NH＋4-N,the middle stream and tributaries are supposed to put main attention in preventing spot-pollution,while the down stream needs to improved the management of environment,specially for the wastewater drainage.For NO-3-N,more attention should be paid to the nitrate management in the downstream of Baoji and Weinan.Rational and high efficiency of fertilize utilization should be widely spread in tributaries.