乌江流域三个梯级水库氮磷形态的比较研究  

Comparative Study on Nitrogen and Phosphorus Species of Three Cascade Reservoirs in Wujiang River Basin

作　　者：刘坤 王仕禄[1] 檀迪 郭明伟 韩祥峰 LIU Kun;WANG Shilu;TAN Di;GUO Mingwei;HAN Xiangfeng(State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550081 [2]中国科学院大学,北京100049

出　　处：《地球与环境》2022年第6期821-830,共10页Earth and Environment

基　　金：云南省重点研发计划(2019BC002);国家自然科学科学基金(U1612442、92047204、U1802241);华能集团科技项目(HNKJ18-H23)。

摘　　要：为揭示河流梯级开发对生源要素氮磷输运的影响,本研究选择乌江流域的普定、乌江渡、思林作为上、中、下游梯级水库的代表,于2020年8月采集各水库水体剖面和沉积物柱样品,测定氮磷含量,并用SMT法提取沉积物磷形态。结果发现,受中下游人为污染输入影响,乌江渡水库水体总氮浓度最高,为3.92±0.50 mg/L,总磷浓度在此坝前到下游急剧抬升为上游的2~3倍,达到0.04~0.06 mg/L;坝前沉积物含有大量的高释放风险的铁铝活性磷(1310.3±1003.3 mg/kg),可能成为下游的潜在污染源。中下游水库较高的生物量加快了氮磷的活化速度,提高了活性磷的浓度,反而减低了沉积物有机磷的生物拦截效率。除乌江渡水库外,其它水库沉积物中以钙结合态磷为主(占无机磷的60%以上)。梯级水库修建后,泥沙含量大幅降低,可能是下游水库沉积物钙结合态磷浓度降低的主要因素。总体上,梯级水库的累积效应使得水库对生源要素的“活化”效率增强、“拦截”效应减弱,增大了富营养化发生的风险。In order to reveal the impact of river cascade development on the transport of biogenic elements nitrogen and phosphorus,water profile and sediment column samples were collected in August 2020 from three reservoirs of Puding,Wujiangdu and Silin in the Wujiang River Basin representing the upper,middle and lower cascade reservoir,respectively.The content of nitrogen and phosphorus in these samples were determined,and the SMT method was used to extract the sediment phosphorus species.The results indicate that the TN concentration in the Wujiangdu Reservoir was the highest,at 3.92±0.50 mg/L,due to the anthropogenic pollution input in the middle and lower reaches,the TP concentration rose sharply from the front of the dam to the downstream,reaching 0.04-0.06 mg/L,which was 2-3 folds of that in the upstream;the sediment in front of the dam contains a large amount of Fe-Al active phosphorus(1310.3±1003.3 mg/kg)with high release risk,which may become a potential source of downstream pollution.The higher biomass in the middle and lower reservoirs accelerated the activation rate of nitrogen and phosphorus,increased the concentration of active phosphorus,but reduced the biological interception efficiency of sediment organic phosphorus.Except for Wujiangdu Reservoir,the sediments of other reservoirs are dominated by calcium-bound phosphorus(accounting for more than 60%of inorganic phosphorus).After the construction of the cascade reservoirs,the sediment content is greatly reduced,which may be the main factor for the decrease of the calcium-bound phosphorus concentration in the sediments of the downstream reservoirs.In general,the cumulative effect of cascade reservoirs increases the‘activation’efficiency of reservoirs on biogenic elements and weakens the‘intercept’effect,which leads to an increase in the concentration of dissolved phosphorus in downstream water bodies and increases the risk of eutrophication.

关 键 词：乌江流域 梯级水库 氮磷形态 氮磷活化 拦截效应 

分 类 号：P593[天文地球—地球化学]