日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 A (大気水圏科学) » A-HW 水文・陸水・地下水学・水環境

[A-HW22] 流域の物質輸送と栄養塩循環-源流域から沿岸海域まで-

2019年5月30日(木) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:小林 政広(国立研究開発法人森林研究・整備機構 森林総合研究所)、吉川 省子(農業・食品産業技術総合研究機構 農業環境変動研究センター)、安元 純(琉球大学 農学部 地域農業工学科)、Adina Paytan(University of California Santa Cruz)

[AHW22-P04] The Tracing of Groundwater Contamination Sources in Indonesian Coastal Alluvial Groundwater using δ34S and δ15N Isotopes

*Anna Fadliah Rusydi1,4Mitsuyo Saito2Seiichiro Ioka3Shin-ichi Onodera1 (1.Graduate School of Integrated Arts and Sciences, Hiroshima University, Japan、2.Graduate School of Environmental and Life Sciences, Okayama University, Japan、3.Research Institute for Sustainable Energy, Hirosaki University, Japan、4.Research Center for Geotechnology, Indonesian Institute of Sciences, Indonesia)

キーワード:Sulfur Isotope, Nitrate Isotope, Coastal Groundwater, Indramayu

The coastal area is one of the Indonesian Government priorities as an archipelago country. The groundwater in the area is one of the most reliable clean water resources, therefore it is crucial to understanding the vulnerability of this resource. Our research area was located at Indramayu, a developing rural coastal area in Indonesia, where, the environment was relatively pristine. This research aimed was to identify the effect of natural condition and human activity to groundwater quality by using stable isotope δ34S and δ15N.



Totally, there were 20 samples taken from groundwater (18) and river (2). The nitrate and sulfate were detected in a total of 5 and 19 samples, respectively. The isotopes composition for isotope nitrate were -11.2 ‰ – +22.22‰ for δ15N-NO3 and -3.4 ‰ – +17.1‰ for δ18O-NO3. Moreover, the values of δ34S-SO4 and δ18O- SO4 were varied from -4.2 ‰ – +28.4‰ and +7.3 ‰ – +18.8 ‰, respectively. The isotopic signatures of nitrate suggested that the used of inorganic fertilizer and animal manure give the impact to both groundwater and river. Similarly, the isotopic signatures of sulfur were showing that those detected sulfate in the groundwater were mostly coming from fertilizer. Moreover, the soil was mineralized by organic sulfate as well. At one point, located in the fishery area, the groundwater was indicated the seawater contamination. It was shown by the heavy composition of sulfur isotope (28.4‰ for δ34S and 18.8‰ for δ18O). Lastly, our results showed those combined isotopes of δ34S and δ15N along with land-use evaluation could explain the possible sources of groundwater in coastal area at very early urbanization stage.