【摘要】 沉积物颗粒通过对氨氮的吸附-解吸影响河水中氮素的含量。以拉萨河上直孔水电站水坝上、下的底泥以及拉萨河末端曲水县的底泥为研究对象,通过氨氮在底泥上的吸附-解吸试验,研究了拉萨河水体底泥对氨氮的吸附-解吸能力及其影响因素。结果表明:在试验的条件范围内,温度和盐度对底泥吸附氨氮的能力影响不大,pH值的增高会提高底泥对氨氮的吸附能力;各底泥对氨氮的吸附是一种分配过程;水坝的截留使坝上底泥中氨氮的本底值含量较高而坝下底泥中砂质含量较高;3种底泥对氨氮的吸附能力表现为直孔坝下>直孔坝上>曲水,其解吸能力表现为直孔坝上>曲水>直孔坝下;由于拉萨河地处西藏高原,土壤矿化、有机质含量低,拉萨河底泥对氨氮的吸附能力普遍比平原地区底泥弱。本研究可了解大坝建设等人类活动对拉萨河水环境的影响,为合理利用拉萨河水资源提供科学依据。更多还原

【Abstract】 Sediment affects the nitrogen content in river water through the adsorption-desorption of ammonia nitrogen.Taking the upstream sediments(ZK-UP)and downstream sediments(ZK-DOWN) of the Dam of Zhikong Hydropower Station on the Lhasa River and the sediments of Qushui County(QS)at the end of the Lhasa River as the research objects,this paper studies the adsorption-desorption capacity of ammonia nitrogen on the sediment and its influencing factors through the adsorption-desorption test of ammonia nitrogen on the sediment.The results show that the ammonia nitrogen adsorption capacity is enhanced as the increasing of pH and shows no obvious changes with the variations of temperature and salinity at the experimental conditions.The adsorption of ammonia nitrogen on the three kinds of sediment is a distribution process.The interception of Zhikong dam results in higher ammonia nitrogen content in the upstream sediment and higher sand content in the downstream sediment.The ammonia nitrogen adsorption capacities of sediments are in order of ZK-DOWN>ZK-UP>QS,while the desorption capacities are in order of ZK-UP>QS>ZK-DOWN.Due to the high altitude,the content of mineral organic matter in the soil is low,the adsorption capacities of the sediments in Lhasa River for ammonia nitrogen are generally less than that of the sediments in the plain area.This study can understand the impact of human activities such as dam construction on the water environment of the Lhasa River and provide scientific basis for rational utilization of the water resources of the Lhasa River.更多还原