白塔堡河上覆水与沉积物间隙水N、P分布特征

为研究河流沉积物与间隙水间营养盐的迁移规律,采集白塔堡河干流平水期上覆水和沉积物间隙水样品,分析N、P分布特征,计算沉积物-水界面N、P扩散通量,并对上覆水与间隙水中营养盐含量进行回归分析. 结果表明:上覆水和间隙水中ρ(TN)、ρ(NH₃-N)和ρ(TP)均为农村带河段最低,城镇带和城市带河段较高. N、P的主要来源,农村带河段为农村灰水和面源污染,城镇带河段为生活污水和工业园排水,城市带河段为城市生活污水和工业废水. 间隙水中各营养盐质量浓度基本上都高于上覆水,空间分布趋势相似. NH₃-N、NO₂--N、NO₃--N和PO₄3--P在沉积物-水界面的平均扩散通量分别为0.429、0.134、0.080和0.143μmol/(m2·d),表明沉积物是上覆水重要的N、P源. 表层沉积物间隙水与上覆水中的ρ(NH₃-N)(R2=0.874,P=0.0002)和ρ(PO₄3--P)(R2=0.704,P=0.0005)均呈极显著相关,ρ(NO₂--N)呈显著相关(R2=0.501,P=0.0020),ρ(NO₃--N)的相关性(R2=0.353,P=0.0150)不显著,说明白塔堡河沉积物间隙水中的N主要以NH₃-N形态向上覆水中扩散；而间隙水中的P主要以PO₄3--P形态向上覆水中扩散. 

Distribution of Nitrogen and Phosphorus in Overlying Water and Pore Water of Sediment in Baitabuhe River

Baitabuhe River is located in the south of Shenyang as a first level tributary of Hunhe River system and a river important to Shenyang. We totally selected 16sampling sites in the Baitabuhe River and collected overlying water and sediments in each sampling site from the main stream. Physico-chemical properties of the main stream in Baitabuhe River were analyzed and the spatial distribution characteristics of nitrogen and phosphorus in the overlying water and pore water of sediment in medium period were discussed. Diffusion flux of nitrogen or phosphorus was measured in the sediment-overlying water interface, and liner regressions of nitrogen were used to determine the phosphorus amounts between overlying water and pore water. The results showed that, for both in overlying water and interstitial water, the concentrations of nitrogen in the river were lowest in the rural region, followed by the town region and the urban region. The nutrients in the rural region originated from the rural grey water and non-point source pollution, in the town region from the domestic sewage and industrial park drainage, and in the urban region from the industrial wastewater and the domestic sewage. The concentrations of the nutrients in the pore water were higher than those in the overlying water. The trend of the spatial distribution of the nutrients in the surface water was similar to that in the pore water. The average diffusion flux across sediment-water interface was 0.429μmol/(m2·d) for NH₃-N, 0.134μmol/(m2·d) for NO₂--N, 0.080μmol/(m2·d) for NO₃--N, and 0.143μmol/(m2·d) for PO₄3--P. The results showed that sediment is one of the important input sources of nitrogen and phosphorus. The concentration of ammonia nitrogen in sediment pore water had a significant correlation with overlying water(R2=0.874, P=0.0002);the concentration of phosphate also had a significant correlation with overlying water(R2=0.704, P=0.0005); but the concentration of nitrite nitrogen between pore water and overlying water was not high(R2=0.501, P=0.0020; the nitrate nitrogen is lower(R2=0.353, P=0.0150. These results showed that the nitrogen of pore water are mainly diffuse by ammonia nitrogen to the overlying water; and the phosphorus of pore water mainly diffuse by phosphate to the overlying water.