自然冰冻对松花江冰与水中硝基苯分配的影响

为了解松花江水中硝基苯在自然冰冻情况下的归趋,在冬季室外自然气候条件下进行硝基苯水样冰冻实验,并且对松花江达连河断面主河道冰层中硝基苯含量进行分层检测.结果表明,在水样全部结冰情况下,冰中硝基苯质量浓度(以融化后水中硝基苯质量浓度计,下同)与原水样中硝基苯质量浓度比值与冰冻速度没有明显关系,其比值一般在0.47~0.80;而在水样不完全结冰情况下,结冰速度对硝基苯在冰相与水相中的分配比具有显著影响,快速结冰时分配比为0.21,慢速结冰时仅为0.050.冰冻过程中水中硝基苯逐渐被浓缩,部分硝基苯挥发到大气中.污染带流经达连河断面所结冰的各个层位中硝基苯质量浓度均远远低于国家《地表水环境质量标准》(GB3838—2002)限值.

Natural icing effects on nitrobenzene distribution in ice and water of Songhua River

For understanding nitrobenzene distribution of water under natural ice in Songhua River,nitrobenzene contents of different ice layers of main river way were examined in different layers at Dalianghe in Songhua River.It is shown that nitrobenzene concentrations in ice has no distinct relationship with those in original water samples under entirely icing conditions.The ratio of nitrobenzene concentrations in ice to those in water is 0.47-0.80.The icing velocity has obvious effects on nitrobenzene distributions in ice and water phases under incompletely icing conditions.For fast icing,the distribution ratio of nitrobenzene concentrations in ice to those in water is 0.21; while for slow icing,the distribution ratio was 0.050.During the course of icing,nitrobenzene was condensed gradually and part of nitrobenzene volatilized into the air.When nitrobenzene-polluted band flowed into Dalianhe sections,nitrobenzene concentrations in different layers of the ice were less than the demand of concentrations in the national standard of environmental quality for surface water.