摘要
【目的】水体氮污染依然是当前流域水环境的首要威胁。太湖流域是中国东部经济发达地区的重要水源地,但目前流域水质处于轻度污染状态,因此探究太湖流域水体氮素特征,可为流域水环境的改善提供参考依据。【方法】以太湖上游重要水源区西苕溪流域为研究区,基于浙江省安吉县水文站1956—2023年的降雨观测数据及2016—2023年的水质监测数据,分析该区降雨在不同时间维度上的差异,探究研究区水体氮素的时空动态分布特征,明确西苕溪流域水库型水源地水体氮素随时间的变化特征。【结果】研究区降雨量呈上升趋势,且每年5—9月为雨季,降雨量占全年降雨量的60.04%。时间维度上,由于雨季较多的降雨对水体有稀释作用,因而雨季水库型水源地水体氮素质量浓度一般低于非雨季,特别是2023年雨季老石坎水库水体氮素质量浓度仅为0.02mg·L^(-1),已达Ⅰ类水标准;空间维度上,流域整体呈现西南部流域源头水体氮素质量浓度较低,而中部及东北部人类活动较多的中下游氮素质量浓度较高的特征。对于流域整体水质而言,2016年西苕溪流域水体氮素质量浓度最大值为9.09 mg·L^(-1),均值为3.19 mg·L^(-1),流域整体水质属劣Ⅴ类。而在2023年,西苕溪流域水体氮素质量浓度均值为1.32 mg·L^(-1),整体符合Ⅳ类水的要求。【结论】2016—2023年,流域水质整体呈现好转态势。降雨是影响水体氮素质量浓度的关键因素,在全年尺度上水体氮素质量浓度与降雨量呈负相关,而在季节尺度上水体氮素质量浓度与降雨量呈正相关。
[Objective]Nitrogen pollution in water is still the primary threat to the current water environment in watershed.The Taihu Lake Basin is an important water source area for the economically developed coastal areas in eastern China,but its water quality is currently in a mildly polluted state,and thus,the study of nitrogen characteristics in Taihu Lake Basin provides the reference for improving the water environment of the basin.[Method]This paper took the Xitiaoxi Watershed,an important water source area in the upper reaches of Lake Taihu,as the research area.Based on the rainfall observation data of Anji County Hydrological Station from 1956 to 2023 and the water quality monitoring data from 2016 to 2023,the difference of rainfall in different time dimensions was analyzed,the dynamic distribution characteristics of water nitrogen in the study area were investigated,and the characteristics of water nitrogen change with time in the reservoir-type water source in Xitiaoxi Watershed were defined.[Result]Rainfall in the study area showed an upward trend,and the rainy season was from March to September each year,with accounting for 60.04%of the annual rainfall.From the time dimension,due to the dilution effect of heavy rainfall in rainy season on water body,the water nitrogen concentration of reservoir-type water source in rainy season was generally lower than that in non-rainy season.In particular,the water nitrogen concentration of Laoshikan Reservoir in rainy season in 2023 was only 0.02 mg·L^(-1),which had reached the ClassⅠwater standard.From the spatial dimension,the water nitrogen concentration in the southwest of the watershed was lower,while the nitrogen concentration in the middle and lower reaches where human activities were more frequent was higher.As for the overall water quality of the watershed,the maximum nitrogen concentration of Xitiaoxi Watershed in 2016 was 9.09 mg·L^(-1),and the average was 3.19 mg·L^(-1),indicating that the basin belonged to inferior ClassⅤwater.In 2023,the average nitrogen concentration in Xitiaoxi Watershed was 1.32 mg·L^(-1),which met the requirements of ClassⅣwater.[Conclusion]From 2016 to 2023,the water quality of the watershed as a whole improved.Rainfall was a key factor affecting nitrogen quality concentration in water bodies,on the annual scale,water nitrogen concentration was negatively correlated with rainfall,while on the seasonal scale,water nitrogen concentration was positively correlated with rainfall.
作者
陶志忠
高云云
王荣嘉
TAO Zhizhong;GAO Yunyun;WANG Rongjia(Anji County Bureau of Water Resources,Anji 313300,Zhejiang,China;College of Forestry and Biotechnology,Zhejiang A&F University,Hangzhou 311300,Zhejiang,China)
出处
《浙江农林大学学报》
北大核心
2025年第4期835-843,共9页
Journal of Zhejiang A&F University
基金
国家自然科学基金青年基金资助项目(32401664)
浙江农林大学科研启动项目(2022LFR083)。
关键词
水体氮污染
面源污染
水源地
太湖流域
water nitrogen pollution
non-point source pollution
water source area
Taihu Lake Basin
