δ15N and δ18O Reveal the Sources of Nitrate-Nitrogen in Urban Residential Stormwater Runoff
详细信息 查看全文
- 作者：Yun-Ya Yang ; Gurpal S. Toor
- 刊名：Environmental Science & Technology
- 出版年：2016
- 出版时间：March 15, 2016
- 年：2016
- 卷：50
- 期：6
- 页码：2881-2889
- 全文大小：527K
- ISSN：1520-5851
文摘
Nitrogen (N) sources are widely distributed in the complex urban environment. High-resolution data elucidating N sources in the residential catchments are not available. We used stable isotopes of N and oxygen (O) of nitrate (δ18O-NO3– and δ15N-NO3–) along with δ18O and hydrogen (δD) of water (H2O) to understand the sources and transformations of N in residential stormwater runoff. Stormwater runoff samples were collected over 25 stormwater events at 5 min intervals using an autosampler installed at the residential catchment outlet pipe that drained 31 low-density homes with a total drainage area of 0.11 km2. Bayesian mixing model results indicated that atmospheric deposition (range 43–71%) and chemical N fertilizers (range <1–49%) were the dominant NO3-N sources in the stormwater runoff and that there was a continuum of source changes during the stormwater events. Further, the NO3-N transport in the stormwater runoff from the residential catchment was driven by mixing of multiple sources and biotic (i.e., nitrification) processes. This work suggests that a better understanding of N transport and sources is needed to reduce N export and improve water quality in urban water systems.