潇河流域水体氮素分布特征及其与溶解氧的关系

Nitrogen Distribution in Water of Xiaohe River Watershed and Its Relationship with Dissolved Oxygen

从潇河流域选取15个采样点,研究了水体中3种形态的氮素——氨氮、硝酸盐氮和亚硝酸盐氮的分布特征及其与溶解氧的关系。结果表明,潇河流域水体氮素以亚硝酸盐氮含量最高,除水源保护区为地表水环境质量标准(GB3838—2002)的Ⅰ类水质,其余均为Ⅳ类水质,与潇河晋中段和白马河寿阳段两岸排放的工业废水及城镇生活污水有关;在河口交汇处和河道坡度突变处,水体氮素含量有明显变化;3种形态的氮素在不同程度上受水体溶解氧含量影响:所有采样点的氨氮和亚硝盐氮含量随着溶解氧的增大而减少,受氨氮的影响,3,4,7,9,12号样点的硝酸盐氮含量随溶解氧增大而减少,其余采样点的硝酸盐氮含量随溶解氧增大而增大;通过线性回归分析可知,只有亚硝酸盐氮含量和溶解呈显著相关。

Fifteen sites were selected for water sampling from the Xiaohe River watershed to study the distribution of ammonia,nitrate and nitrite and their relationship with dissolved oxygen.It was found that the contents of HNO2—N at all the sampling sites are relatively high.Except water conservation area with a gradeⅠ of surface water quality according to the national standard（GB3838—2002）,the rest sites belonged to GradeⅣ,which was associated with the discharges of both industrial and domestic effluents along the river system of Xiaohe River in Jinzhong section and Baima River in Shouyang section.The contents of water nitrogen have a reamarkable change in river interchange and channel slope mutation place.Three nitrogen were affected by the contents of water dissolved oxygen in different degree：the contents of NH3—N and HNO2—N at all the sampling sites reduced with the increase of dissolved oxygen.Influenced by NH3—N,the contents of HNO3—N at S3,S4,S7,S9 and S12Sites were reduced with the increase of dissolved oxygen,the contents of HNO3—N at all the rest sites increased with the increase of dissolved oxygen.The linear regression analysis showed that only the contents of HNO2—N had a significant correlation with dissolved oxygen.