引用本文: | 高凤,邵美玲,曹昌丽,汪文东,易辉,唐剑锋.城镇化流域氮、磷污染特征及影响因素——以宁波北仑区小浃江为例.湖泊科学,2019,31(3):689-699. DOI:10.18307/2019.0308 |
| GAO Feng,SHAO Meiling,CAO Changli,WANG Wendong,YI Hui,TANG Jianfeng.Nitrogen and phosphorus pollution characteristics and influencing factors in urbanized watershed-A case study of Xiaojia River in Beilun District, Ningbo City. J. Lake Sci.2019,31(3):689-699. DOI:10.18307/2019.0308 |
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城镇化流域氮、磷污染特征及影响因素——以宁波北仑区小浃江为例 |
高凤1,2, 邵美玲1, 曹昌丽3,2, 汪文东3,2, 易辉3,2, 唐剑锋3,2
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1.安徽师范大学生命科学学院, 安徽省高校生物环境与生态安全省级重点实验室, 芜湖 241000;2.中国科学院宁波城市环境观测研究站, 宁波 315830;3.中国科学院城市环境研究所城市环境与健康重点实验室, 厦门 361000
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摘要: |
我国快速的城镇化过程造成了河流氮、磷等营养盐的污染和潜在的水体富营养化问题.对城镇流域水体氮、磷污染特征及其演变趋势的识别具有重要意义.本研究选取长三角典型城镇地区宁波市北仑区小浃江流域为研究对象,在流域内根据空间分布、土地利用类型、人类活动强度等情况布设样点,于2017年夏季和冬季采集水样,研究流域水体氮、磷污染的时空分布特征并分析其污染来源和评估其富营养化水平.结果表明:流域内铵态氮(NH4+-N)、;硝态氮(NO3--N)、亚硝态氮(NO2--N)、总氮(TN)、总磷(TP)和叶绿素a(Chl.a)浓度范围分别为0.63~3.25 mg/L、0.52~3.75 mg/L、0.02~0.22 mg/L、1.61~12.86 mg/L、0.02~0.74 mg/L和0.6~60.57 μg/L.各个采样点氮、磷分布具有较大的空间异质性和季节变化规律.富营养化综合指数EI评估结果显示,整个流域富营养化程度属于贫至中营养级.氮、磷浓度与土地类型面积占比的Spearman相关性统计表明,100 m缓冲区建设用地面积占比与NH4+-N、NO2--N、TN、溶解氧(DO)浓度具有显著相关性,湿地面积占比与DO浓度呈显著正相关.汇水区域内林地面积占比与NH4+-N、NO2--N、TP、PO43--P、COD、Chl.a浓度呈显著负相关,与DO浓度呈显著正相关.相关性分析和冗余分析表明城镇化的面源污染及可能存在的点源污染是小浃江流域氮、磷污染的主要来源.因此,在小浃江流域100 m范围内,控制建设用地的规模和污染排放是减轻流域氮、磷污染的主要途径.在汇水区域内,增加林地植被的面积对减少氮、磷污染具有重要影响. |
关键词: 城镇化流域 小浃江 氮、磷污染 富营养化 空间特征 影响因素 |
DOI:10.18307/2019.0308 |
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基金项目:国家重点研发计划项目(2017YFE0119000)和中国科学院城市环境与健康重点实验室项目(KLUEH-C-201701)联合资助. |
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Nitrogen and phosphorus pollution characteristics and influencing factors in urbanized watershed-A case study of Xiaojia River in Beilun District, Ningbo City |
GAO Feng1,2, SHAO Meiling1, CAO Changli3,2, WANG Wendong3,2, YI Hui3,2, TANG Jianfeng3,2
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1.College of Life Sciences, Anhui Normal University, Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province, Wuhu 241000, P.R.China;2.Ningbo Urban Environment Observation and Research Station, Chinese Academy of Sciences, Ningbo 315830, P.R.China;3.Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361000, P.R.China
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Abstract: |
Rapid urbanization in China leads to serious eutrophication problem as extra nitrogen and phosphorus input urban watersheds. Therefore, it is important to trace nitrogen and phosphorus pollution to control and manage water quality in those areas. In this study, the spatial and temporal distribution of nitrogen and phosphorus were analyzed in Xiaojia River watershed which located at an urban area of Ningbo in the Yangtze River Delta. The influence factors of eutrophication problem were also analyzed. Water samples for nitrogen and phosphorus were collected in summer and winter of 2017 based on land-use type and topographic features. The results showed that the concentration of nitrogen and phosphorus varied at large scales:ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), nitrite nitrogen (NO2--N), total nitrogen (TN), total phosphorus (TP) and chlorophyll-a (Chl.a) concentrations were 0.63-3.25 mg/L, 0.52-3.75 mg/L, 0.02-0.22 mg/L, 1.61-12.86 mg/L, 0.02-0.74 mg/L and 0.60-60.57 μg/L, respectively. Large spatial and seasonal variations were found across the sampling sites in the studied watershed. We use the synthetic eutrophication index EI to assess eutrophication level in watershed, and the results showed that the watershed has eutrophication level of poor to medium. The Spearman correlation statistics for the 100 m buffer area showed that the concentration of NH4+-N (R2=0.639, P<0.05), NO2--N (R2=0.591, P<0.05), TN (R2=0.674, P<0.01) and DO (R2=-0.660, P<0.01) were positively correlated with construction land ratio. The wetland was significantly positive correlated to DO (R2=0.528, P<0.05). In the catchment area, the forest ratio was negatively correlated with NH4+-N (R2=-0.594, P<0.05), NO2--N (R2=-0.736, P<0.01), TP (R2=-0.663, P<0.01), PO43--P (R2=-0.533, P<0.05), COD (R2=-0.659, P<0.01), Chl.a (R2=-0.531, P<0.05). But it was positively correlated with DO (R2=0.756, P<0.01) and Correlation statistics and RDA sequencing analysis showed that the principle sources of nitrogen and phosphorus pollution in Xiaojia River watershed were strongly associated with urban non-point source and some point source that exist along the river. Therefore, restricting the construction land scale and pollutant discharge are the main routes to decrease nitrogen and phosphorus pollution in 100 m buffer area. However, enlarge the forest ratio is important for controlling nitrogen and phosphorus pollution in the catchment area. |
Key words: Urbanized watershed Xiaojia River nitrogen and phosphorus pollution eutrophication spatial characteristics influence factor |
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