Zhang Tian-Na, Zhou Shi-Lei, Chen Zhao-Ying, Zhang Zi-Wei, Sun Yue, Yao Bo, Cui Jian-Sheng, Li Zai-Xing, Luo Xiao
Pollution Prevention Biotechnology Laboratory of Hebei Province, School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China.
Huan Jing Ke Xue. 2021 Jul 8;42(7):3176-3185. doi: 10.13227/j.hjkx.202011136.
In order to reveal the interaction of overlying water-interstitial water nitrogen and phosphorus nutrient salt in summer at the entrance region of Baiyangdian Lake, this study sampled six main rivers in the region during July 2019. An analysis of the overlying water and interstitial water quality characteristics and the diffusion flux of applied nutrients at the sediment-water interface revealed the effects of nutrient diffusion on sediments and overlying water. The overlying water analysis showed that the water quality was slightly alkaline in the Baiyangdian Lake. The content of dissolved oxygen (DO) was lower, which provided an anaerobic environment for the release of endogenous pollutants from sediments. The ammonia nitrogen (NH-N) ranged from 0.35 to 1.76 mg·L, and the content of ammonia nitrogen was the highest in the Zhulong River, which was the main source of water supply. The nitrate nitrogen (NO-N) content ranged from 0.75 to 1.97 mg·L. The total dissolved nitrogen (TDN) ranged from 0.99 to 2.70 mg·L, and the content of TDN was the highest in Puhe River. The content of total dissolved phosphorus (TDP) was 0.03 to 0.15 mg·L, and the content of TDP was the highest was Baigouyin River, which is near the residential area. The results indicated that the content of ammonia nitrogen in the interstitial water was between 5.24 and 10.64 mg·L, which was 10 times that of the overlying water, and endogenous pollution in the former was severe. The nitrate nitrogen content ranged from 0.36 to 0.79 mg·L. The total dissolved nitrogen content was between 5.36 and 12.02 mg·L, which was 5 times higher than that of the overlying water. The total dissolved phosphorus was between 0.03 and 0.3 mg·L. According to integrated pollution index, the degree of interstitial water pollution was much higher than that of overlying water, and the sampling points are seriously polluted. The exchange flux analysis of NH-N, TDN, and TDP demonstrated that the diffusion flux of NH-N was between 1.71 and 7.43 mg·(m·d), and the diffusion rate of endogenous ammonia nitrogen to the overlying water was fastest in Fu River, the absorbing river in Baoding. The diffusion flux of total dissolved nitrogen was lower in the Baigouyin River, and the other five sample points averaged 9.11 mg·(m·d). In summer, the dissolved oxygen was lower and the water-sediment had a larger concentration difference, which led to massive nitrogen nutrient of sediment in anaerobic conditions released to the overlying water in great quantities that caused the serious pollution. The diffusion flux of dissolved total phosphorus showed that the sediment of Pinghe River acted as a "sink" of phosphorus nutrients, and the other sampling points ranged from 0.03 to 0.16 mg·(m·d), showing the state of phosphorus nutrient released upward to the overlying water. Finally, diffusion flux indicated that endogenous pollutants are crucial sources of overlying water pollutants. In order to effectively control the water quality in the entrance area, desilting the nitrogen and phosphorus nutrient salt of sediment is urgently required.
为揭示白洋淀入湖口区域夏季上覆水-间隙水氮磷营养盐的相互作用，本研究于2019年7月对该区域六条主要河流进行了采样。通过对上覆水和间隙水水质特征以及沉积物-水界面营养物质扩散通量的分析，揭示了营养物质扩散对沉积物和上覆水的影响。上覆水分析表明，白洋淀水质呈弱碱性。溶解氧（DO）含量较低，为沉积物中内源污染物的释放提供了厌氧环境。氨氮（NH-N）含量在0.35至1.76mg·L之间，其中潴龙河氨氮含量最高，是主要供水水源。硝酸盐氮（NO-N）含量在0.75至1.97mg·L之间。总溶解氮（TDN）含量在0.99至2.70mg·L之间，其中瀑河TDN含量最高。总溶解磷（TDP）含量在0.03至0.15mg·L之间，其中白沟引河（靠近居民区）TDP含量最高。结果表明，间隙水中氨氮含量在5.24至10.64mg·L之间，是上覆水的10倍，内源污染严重。硝酸盐氮含量在0.36至0.79mg·L之间。总溶解氮含量在5.36至12.02mg·L之间，是上覆水的5倍。总溶解磷含量在0.03至0.3mg·L之间。综合污染指数表明，间隙水污染程度远高于上覆水，采样点污染严重。NH-N、TDN和TDP的交换通量分析表明，NH-N的扩散通量在1.71至7.43mg·(m·d)之间，内源氨氮向上覆水的扩散速率在保定市的汇入河流府河中最快。白沟引河总溶解氮的扩散通量较低，其他五个采样点平均为9.11mg·(m·d)。夏季，溶解氧较低，水-沉积物浓度差较大，导致沉积物中的大量氮营养物质在厌氧条件下大量释放到上覆水中，造成严重污染。溶解总磷的扩散通量表明，萍河沉积物为磷营养物质的“汇”，其他采样点在0.03至0.16mg·(m·d)之间，呈现磷营养物质向上覆水释放的状态。最后，扩散通量表明内源污染物是上覆水污染物的重要来源。为有效控制入湖口区域水质，急需清除沉积物中的氮磷营养盐。
