珠江广州段上覆水及间隙水中氮的分布特征

Characteristics of Nitrogen Distribution in Overlying Water and Pore Water in Guangzhou Reach of Pearl River

通过现场调查与实验测试方法,研究了珠江广州河段上覆水与间隙水中不同形态氮含量的空间分布特征,并分析这两种赋存介质中各形态氮间的相关性。结果表明,沉积物间隙水中总氮、有机氮与氨氮远高于上覆水,而硝态氮则相反。上覆水总氮的平均含量为13.62 mg/L,前航道的平均含量明显高于西航道,从西航道到前航道呈现逐渐升高的趋势,并以有机氮为主要形态,两者呈现显著正相关;间隙水总氮的平均含量为51.31 mg/L,从西航道到前航道略有升高的趋势,但变化不如上覆水明显,以氨氮为主要形态,总氮与氨氮、有机氮三者间均呈显著正相关。相关性分析还表明,各形态氮在间隙水和上覆水中的含量均无明显相关性,说明间隙水中赋存的氮含量不是其上覆水中含量的决定因素。

This paper reports on a survey conducted in Guangzhou City’s river section of the Pearl River for investigation of nitrogen spatial distribution involving TN,ON（organic nitrogen）,ammonia（NH4＋-N）and nitrate nitrogen（NO3--N,NO2--N） with respect to the overlying and pore water;meanwhile,relationship among different nitrogen forms is analyzed based on the assay results.Findings of the survey show that concentrations of TN,ON and ammonia in pore water are much higher than those in overlying water,while on the contrary,nitrite concentration is higher in pore water;the average concentration of TN is 13.62 mg/L in overlying water and TN average concentration is higher in the fore channel compared to that in the west channel.Meanwhile,as to the pore water average concentration of TN is 51.51 mg/L with NH4＋-N being the main form of nitrogen,showing significant positive correlation between TN,ON,and ammonia.In so far as the correlation analysis for various forms of nitrogen,no remarkable correlations are found between pore water and overlaying,indicating that nitrogen content in the pore water is not the determinate factor that controls that in the overlying water.