Stable isotope on the evaluation of water quality in the presence of WWTPs in rivers

다국어 초록 (Multilingual Abstract)

<P>We investigated the distribution of nitrogen compounds in Han River as well as two tributaries of Tancheon and Jungrangcheon. Particularly, we observed the significant releases of NH4+-N from effluent of wastewater treatment plants (WWTPs) in two tributaries that has resulted in the increases of ammonium nitrogen (NH4+-N) in Han River as well as in Tancheon and Jungrangcheon. Due to the increases of NH4+-N in two tributaries, the larger distribution of delta N-15-NH4+ was observed than those of delta N-15-NO3- in downstream. We calculated the contribution rate of ammonium nitrogen and nitrate nitrogen from effluent to downstream according to the results of stable isotope. The contribution rates of delta N-15-NH4+ from effluent to downstream were significant that ranged between 53 and 100 % in Tancheon and between 27 and 100 % in Jungrangcheon. While the contribution of delta N-15-NO3- was not significant in Tancheon, it was occasionally observed in Jungrangcheon. These results demonstrated that WWTPs are the major sources of NH4+-N in two tributaries, which caused the distinguishable stable isotope of delta N-15-NH4+. Therefore, the stable isotope of delta N-15-NH4+ could be a useful parameter or tracer for the evaluation of NH4-N released from WWTPs in rivers.</P>