摘要
洞庭湖是我国第二大淡水湖,研究洞庭湖水质总磷(TP)浓度变化规律对其水环境管理意义重大.基于2017年—2021年东洞庭湖及入湖、出湖共12个水质断面数据,研究了东洞庭湖总磷浓度时空分布特征与污染成因.研究结果表明:2017年—2021年东洞庭湖总磷质量浓度ρ(TP)年均值在0.058~0.088 mg/L,湘江、环湖河流及南洞庭湖入湖ρ(TP)年均值在0.051~0.125 mg/L;出湖ρ(TP)年均值在0.062~0.079 mg/L,均超过湖库Ⅲ类水质标准.其中,东洞庭湖以轻度、偏中度污染为主,洞庭湖出口以轻度污染为主.各入湖水质中,湘江以轻度、偏中度污染为主,环湖河流以中度污染为主,南洞庭湖为轻度污染.东洞庭湖及入湖水质ρ(TP)空间分布和时间变化差异明显.空间分布上,环湖河流明显大于湘江,东洞庭湖明显大于洞庭湖出口和南洞庭湖入水;时间变化上,东洞庭湖、洞庭湖出口、汨罗江、新墙河与华容河枯水季节(年初和年末)ρ(TP)明显偏高,达到0.082~0.117 mg/L,但藕池河东支ρ(TP)高峰期却出现在丰水季节,达到0.094~0.115 mg/L;湘江及南洞庭湖入湖ρ(TP)波动幅度较小,基本保持在0.049~0.090 mg/L.相关性分析与RDA分析结果进一步表明:东洞庭湖及出湖水质受外源污染物输入和水文条件的叠加影响,其中洞庭湖出口水位及流量、湘江及藕池河东支水位变化,以及新墙河、横岭湖入湖ρ(TP)对东洞庭湖及出湖ρ(TP)影响较大.上述研究结果表明:在不同水文阶段积极开展水文调控工作对改善东洞庭湖水质有重要作用,同时,加强对重点河段入湖外源污染物的管控能进一步改善东洞庭湖磷浓度的调控效果.
Dongting Lake is the second largest freshwater lake in China.To study the variation law of total phosphorus(TP)concentration is of great significance to its water environment management.Based on the water quality data of twelve sections in East Dongting Lake and its influx and outflux from 2017 to 2021,the temporal and spatial distribution characteristics and polluting causes of total phosphorus concentration in East Dongting Lake are studied.Results show that the annual average of ρ(TP)from 2017 to 2021 in East Dongting Lake ranges from 0.058 to 0.088 mg/L,and the annual average of ρ(TP)ranges from 0.051 to 0.125 mg/L in Xiangjiang River,the rivers around East Dongting Lake and South Dongting Lake.The annual average of ρ(TP)of the outflux of Dongting Lake ranges from 0.062 to 0.079 mg/L.The above all exceed the class III Water quality standards for lakes and reservoirs.Among them,the East Dongting Lake is mainly slightly and moderately polluted,but the outlet of Dongting Lake is mainly slightly polluted.As regards the water quality influx of East Dongting Lake,the Xiangjiang River is mainly slightly polluted and moderately polluted,the rivers around East Dongting Lake are mainly moderately polluted,and the South Dongting Lake is slightly polluted.The average of ρ(TP)in East Dongting Lake and its influx and outlux shows obvious differences in spatial distribution and temporal variation.In terms of spatial distribution,the rivers around East Dongting Lake are significantly larger than the Xiangjiang River,and the East Dongting Lake is significantly larger than the outlet of Dongting Lake and the inlet of South Dongting Lake.In terms of time change,the content of ρ(TP)shows high in dry season(at the beginning and the end of the year)in East Dongting Lake,outflux of the Dongting Lake,Miluo River,Xinqiang River and Huarong River,reaching 0.082~0.117 mg/L.However,the peak concentration of east branch of Ouchi River appears in the wet season,reaching 0.094~0.115 mg/L.Xiangjiang River and South Dongting Lake fluctuate slightly and remain at 0.049~0.090 mg/L.Results of correlation analysis and redundancy analysis further show that the water quality of East Dongting Lake and its outflux is affected by the superposition of external pollutant inputs and hydrological conditions.Changes in the water level and flux at the outlet of the Dongting Lake,the water level of Xiangjiang River and the east branch of Ouchi River,and the ρ(TP)of influx of Xinqiang River and Hengling Lake all have a great impact on the East Dongting Lake and its outlux.The above research results show that carrying out hydrological regulation actively in different hydrological stages play important role in improving the water quality of the East Dongting Lake.At the same time,strengthening the control of external pollutants from key river sections will further improve the control effect of phosphorus concentration in the East Dongting Lake.
作者
吴丁
方平
李照全
刘淑军
庄琼华
王波
WU Ding;FANG Ping;LI Zhaoquan;LIU Shujun;ZHUANG Qionghua;WANG Bo(Yueyang Eco-Environmental Monitoring Centre of Hunan Province,Yueyang 414000,China;Eco-Environmental Monitoring Central of Dongting Lake of Hunan Province,Yueyang 414000,China;Red Soil Experimental Station of CAAS in Hengyang,National Observation and Research Station of Farmland Ecosystem in Qiyang,Qiyang 426182,China;Yueyang Eco-Environmental Affairs Center,Yueyang 414000,China)
出处
《湖南科技大学学报(自然科学版)》
CAS
北大核心
2023年第3期97-105,共9页
Journal of Hunan University of Science And Technology:Natural Science Edition
基金
湖南省自然科学基金资助项目(2019JJ40291)。
关键词
东洞庭湖
总磷
时空分布
污染评价
水环境管理
East Dongting Lake
total phosphorus
temporal and spatial distribution
pollution assessment
water environment management