渭河西安市段铝污染状况及其来源分析

以渭河西安段为重点，对地表水环境中铝污染的状况进行考察.结果表明，渭河西安段及周边水域中铝浓度范围为0.20~0.66 mg·L-1，高于美国、加拿大的水质量标准，已足以对人体健康形成危害.渭河流经西安市后，尽管流量由36.4 m3·s-1升高到81.7 m3·s-1，但铝浓度仍由0.29 mg·L-1升高到0.43 mg·L-1，铝总量增加了2.4倍.2008年5月份由西安市进入渭河的铝总量达66 t，其中有1/5来自皂河.废水处理过程采用的絮凝剂是造成河流中铝浓度升高的重要原因，其中相当一部分来自造纸厂.随着2008年8月开始实施更加严格的造纸工业水污染物排放标准，投加混凝剂成为重要的水处理手段，所有被调查企业均使用含铝盐的絮凝剂，这是地表水环境中铝浓度上升的主要原因.

Status and source analysis of aluminum pollution in Xi'an section of the Weihe River

A preliminary study on aluminum pollution in the Xi'an section of the Weihe River was carried out. The results indicated that aluminum salt concentrations in the Weihe River ranged from 0.20 mg·L^-1 to 0.66 mg·L^-1,all of which exceed the water quality criteria of both the US and Canada and could do harm to human health. Although the flow rate of Weihe River increased from 36.4 m³·s^-1 to 81.7 m³·s^-1 after flowing through Xi'an,the aluminum concentration still rose to 0.43 mg·L^-1 from the initial value of 0.29 mg·L^-1; and the total amount of aluminum increased 2.4 times. During May 2008,a total of 66 tons of aluminum flowed into the Weihe River from Xi'an,of which one-fifth came from the Zaohe River. According to this investigation,the major cause of the increase of aluminum concentration in rivers was the flocculants used in wastewater treatment process,a great part of which were from paper mills. Since August 2008,stricter discharge standards for the paper making industry have been put into practice in China,so chemical flocculation plays an increasingly important role in wastewater treatment. All plants investigated use aluminum salts as flocculants,and this is the main reason why the aluminum concentration rose in the surface waters.