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摘要 于2013年1月（枯水期）、6月（丰水期）对赣江干流及主要支流的24个采样点进行水样采集，分析研究了赣江水体NO3-N、NH4+N 以及NO2-N的时空分布特征。结果表明，赣江水体无机氮的主要形式为NO3-N，约占78%，其次为NH4+N，NO2-N含量很小，平均浓度低于0.02 mg/L。赣江枯水期NO3-N平均含量为1.86 mg/L，略高于丰水期的1.74 mg/L；枯水期NH4+N含量为0.59 mg/L，高于丰水期的0.45 mg/L。枯水期赣江流域上游到下游NO3-N和DIN含量呈现先下降后逐渐上升的趋势，NH4+N含量在赣州附近出现最大值，其次在南昌下游赣江南支，其他地区含量较小，反映了城市污水排放对NH4+N的影响。丰水期上游至下游NO3-N含量呈逐渐下降趋势，但降幅不大，NH4+N含量变化趋势与枯水期相似。主要支流中枯、丰水期以S06样点（桃江）的DIN含量和NO3-N含量最高，主要原因为桃江流域农业化肥的氮输入；其次为S18样点（袁水），可能与新余市大量排放工业废水有关。
关键词 无机氮；赣江流域；时空分布；氨态氮；硝态氮
中图分类号 S273.5 文献标识码 A 文章编号 0517-6611（2014）11-03348-04
Abstract We sampled river water regularly in 24 sampling points dispersed in the mainstream and major tributaries in June 2013（flood season） and January of 2013（dry season）， the spatial and temporal distribution characteristics of nitrogen in the Ganjiang River were studied. The results indicated that nitrate N （NO3-N） was the main composition of inorganic N， which is 78%， followed by NH4+N， and NO2-N concentration is very few， that average concentration is less than 0.02 mg/L. The average of NO3-N is 1.86mg/L in dry season in the Ganjiang River， higher than that of flood season， which is 1.74 mg/L； the average of NH4+N is 0.59 mg/L in dry season， higher than that of flood season， which is 0.45 mg/L.The concentrations of NO3-N and DIN showed a increasing trend after the first decline from upstream to downstream in the Ganjiang River during dry season， while NH4+N has maximum value near downstream of Ganzhou and Nanchang， which are much higher than other samples. That reflects the influence of the urban wastewater discharge on NH4+N. The concentrations of NO3-N showed slight decreasing trend from upstream to downstream in Ganjiang River during flood season，The concentrations of NH4+N showed the similar tend to the dry season. In tributaries， sample at S16（Taojiang River）has high value in DIN and NO3-N concentration in both dry season and flood season， due to nitrogen input of agricultural fertilizer in surrounding areas； sample at S18 （Yuanshui River） followed， probably because of industrial wastewater discharge of Xinyu.
Key words Inorganic nitrogen； Ganjiang River； Spatial and temporal distribution； Ammonia nitrogen； Nitrate nitrogen
近年来随着社会经济的快速发展，以及未经处理的城镇工业和生活污水的大量排放，打破了河流、湖泊的生态系统平衡，水环境面临着严重的威胁，在我国，63.6%的河流、湖泊呈富营养化[1]。氮、磷等营养盐的过量输入是导致水体出现富营养化现象的主要原因，水体富营养化已经成为河流、湖泊和水库等地表水体的重要水环境问题[2-4]。富营养化改变了水体的理化性质，使水中生物异常，水体透明度和溶解氧下降，水体生态系统和水功能受到严重的破坏，对人体健康和生活存在严重危害[5]。
鄱阳湖是我国第一大淡水湖，具有生态多样性丰富的水生生态系统。近年来，鄱阳湖的水质呈逐年恶化的趋势，总氮和总磷的浓度大幅度增加，分别从1988年的0.68 mg/L和 0.07 mg/L增长到2010年1.20 mg/L和0.11 mg/L[6-9]。大量的氮素经由赣江汇入水流相对缓慢的鄱阳湖引起水体富营养化[5]。
关键词 无机氮；赣江流域；时空分布；氨态氮；硝态氮
中图分类号 S273.5 文献标识码 A 文章编号 0517-6611（2014）11-03348-04
Abstract We sampled river water regularly in 24 sampling points dispersed in the mainstream and major tributaries in June 2013（flood season） and January of 2013（dry season）， the spatial and temporal distribution characteristics of nitrogen in the Ganjiang River were studied. The results indicated that nitrate N （NO3-N） was the main composition of inorganic N， which is 78%， followed by NH4+N， and NO2-N concentration is very few， that average concentration is less than 0.02 mg/L. The average of NO3-N is 1.86mg/L in dry season in the Ganjiang River， higher than that of flood season， which is 1.74 mg/L； the average of NH4+N is 0.59 mg/L in dry season， higher than that of flood season， which is 0.45 mg/L.The concentrations of NO3-N and DIN showed a increasing trend after the first decline from upstream to downstream in the Ganjiang River during dry season， while NH4+N has maximum value near downstream of Ganzhou and Nanchang， which are much higher than other samples. That reflects the influence of the urban wastewater discharge on NH4+N. The concentrations of NO3-N showed slight decreasing trend from upstream to downstream in Ganjiang River during flood season，The concentrations of NH4+N showed the similar tend to the dry season. In tributaries， sample at S16（Taojiang River）has high value in DIN and NO3-N concentration in both dry season and flood season， due to nitrogen input of agricultural fertilizer in surrounding areas； sample at S18 （Yuanshui River） followed， probably because of industrial wastewater discharge of Xinyu.
Key words Inorganic nitrogen； Ganjiang River； Spatial and temporal distribution； Ammonia nitrogen； Nitrate nitrogen
近年来随着社会经济的快速发展，以及未经处理的城镇工业和生活污水的大量排放，打破了河流、湖泊的生态系统平衡，水环境面临着严重的威胁，在我国，63.6%的河流、湖泊呈富营养化[1]。氮、磷等营养盐的过量输入是导致水体出现富营养化现象的主要原因，水体富营养化已经成为河流、湖泊和水库等地表水体的重要水环境问题[2-4]。富营养化改变了水体的理化性质，使水中生物异常，水体透明度和溶解氧下降，水体生态系统和水功能受到严重的破坏，对人体健康和生活存在严重危害[5]。
鄱阳湖是我国第一大淡水湖，具有生态多样性丰富的水生生态系统。近年来，鄱阳湖的水质呈逐年恶化的趋势，总氮和总磷的浓度大幅度增加，分别从1988年的0.68 mg/L和 0.07 mg/L增长到2010年1.20 mg/L和0.11 mg/L[6-9]。大量的氮素经由赣江汇入水流相对缓慢的鄱阳湖引起水体富营养化[5]。