%0 Journal Article
%T Temporal and Spatial Variations of the Nitrate-nitrogen Sources in an Underground River Using 15N Isotope Technique<br>基于15N 同位素示踪技术的地下河硝态氮来源时空变化特征分析
%A WANG Zhi-jun
%A YANG Ping-heng
%A KUANG Ying-lun
%A HE Qiu-fang
%A YUAN Wen-hao
%A YUAN Dao-xian
%A <br>汪智军
%A 杨平恒
%A 旷颖仑
%A 贺秋芳
%A 袁文昊
%A 袁道先
%J 环境科学
%D 2009
%I 
%X Groundwater in Qingmuguan underground river was monitored using hydro-chemical and ~(15)N isotope techniques to investigate temporal and spatial variations of nitrate-nitrogen and its possible sources from October,2007 to October,2008. The results show that nitrate concentrations are 3.20 mg/L of the inlet (D1) and 20.35 mg/L of the outlet (S2) of the underground river. Affected by the fertilizers in agricultural field and the rainfall flush and dilution,nitrate concentrations of groundwater are higher but less stable from April to July, 2008 than that from October,2007 to March,2008. They are elevated during August and September, 2008 due to the residual fertilizers and decreased rainfall events. According to the NO_3~--δ~(15)N values of -0.857‰±2.01‰ (n=9),the sources of nitrate-nitrogen of D1 are dominated by residual fertilizers from the paddy fields from October,2007 to March,2008 and from July to October,2008,while the NO_3~--δ~(15)N values of 2.50‰±0.29‰ (n=3) demonstrate that the mixture of soil organic nitrogen and fertilizers are the sources from April to middle and late June,2008. And the NO_3~--δ~(15)N values of -3.74‰ in late May and 0.52‰ in early June indicate that the nitrate-nitrogen comes from fertilizers applied in the paddy fields in 2008. The nitrate-nitrogen of S2 is partly from fertilizers in the upper basin,and also from fertilizers and soil organic nitrogen carried by lateral fissure and soil permeation water of forest and farm land in the middle and lower basin. The NO_3~--δ~(15)N values of 4.77‰±0.73‰ (n=9) show nitrate-nitrogen of S2 mainly originates from fertilizers from October,2007 to March,2008 and from July to October, 2008,while NO_3~--δ~(15)N values of 3.16‰±0.39‰ (n=5) explain that the nitrate-nitrogen derives from the mixture of soil organic nitrogen and fertilizers from April to June, 2008.
%K underground river
%K ~(15)N isotope
%K nitrate-nitrogen
%K source
%K temporal and spatial variations<br>地下河
%K ~(15)N同位素
%K 硝态氮
%K 来源
%K 时空变化
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=3FF3ABA7486768130C3FF830376F43B398E0C97F0FF2DD53&cid=A7CA601309F5FED03C078BCE383971DC&jid=64CD0AA99DD39F69401C615B85F123EF&aid=1E620E88486ADCFDCECFC2ADCAC30F19&yid=DE12191FBD62783C&vid=340AC2BF8E7AB4FD&iid=59906B3B2830C2C5&sid=214686C121F34DFB&eid=2D6C4586EC4133A4&journal_id=0250-3301&journal_name=环境科学&referenced_num=3&reference_num=22