On the use of coprostanol to identify source of nitrate pollution in groundwater

JOURNAL OF HYDROLOGY

卷:550

Article

Nakagawa, Kei¹  Amano, Hiroki¹  Takao, Yuji¹  Hosono, Takahiro²  Berndtsson, Ronny^3,4 

[1] Nagasaki Univ, Grad Sch Fisheries & Environm Sci, 1-14 Bunkyo Machi, Nagasaki 8528521, Japan

[2] Kumamoto Univ, Prior Org Innovat & Excellence, Kurokami 2-39-1, Kumamoto 8608555, Japan

[3] Lund Univ, Div Water Resources Engn, Box 118, SE-22100 Lund, Sweden

[4] Lund Univ, Ctr Middle Eastern Studies, Box 118, SE-22100 Lund, Sweden

关键词: Groundwater;    Nitrate pollution;    Stable isotopes;    Coprostanol;   

DOI  :  10.1016/j.jhydrol.2017.05.038

来源: Elsevier

【 摘 要 】

Investigation of contaminant sources is indispensable for developing effective countermeasures against nitrate (NO3-) pollution in groundwater. Known major nitrogen (N) sources are chemical fertilizers, livestock waste, and domestic wastewater. In general, scatter diagrams of delta O-18 and delta N-15 from NO3- can be used to identify these pollution sources. However, this method can be difficult to use for chemical fertilizers and livestock waste sources due to the overlap of delta O-18 and delta N-15 ranges. In this study, we propose to use coprostanol as an indicator for the source of pollution. Coprostanol can be used as a fecal contamination indicator because it is a major fecal sterol formed by the conversion of cholesterol by intestinal bacteria in the gut of higher animals. The proposed method was applied to investigate NO3- pollution sources for groundwater in Shimabara, Nagasaki, Japan. Groundwater samples were collected at 33 locations from March 2013 to November 2015. These data were used to quantify relationships between NO3- N, delta N-18-NO3-, delta O-18-NO3-, and coprostanol. The results show that coprostanol has a potential for source identification of nitrate pollution. For lower coprostanol concentrations (<30 ng L-1) in the nitrate polluted group, fertilizer is likely to be the predominant source of NO3-. However, higher concentration coprostanol samples in the nitrate-polluted group can be related to pollution from livestock waste. Thus, when conventional diagrams of isotopic ratios cannot distinguish pollution sources, coprostanol may be a useful tool. (C) 2017 Elsevier B.V. All rights reserved.

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