Water, Air, and Soil Pollution

, Volume 200, Issue 1–4, pp 253–265

Long-Term Declining Trends in River Water pH in Central Japan

  • Hiroki Matsubara
  • Shingo Morimoto
  • Hiroyuki Sase
  • Tsuyoshi Ohizumi
  • Hiroshi Sumida
  • Makoto Nakata
  • Hiromasa Ueda
Article

Abstract

pH monitoring data for public water bodies in Niigata and Gifu prefectures in central Japan were tested by the nonparametric seasonal Mann–Kendall method to evaluate long-term acidification. A significant long-term declining trend in river water pH was found in several watersheds in Niigata and Gifu prefectures. In Niigata, the declining trend was observed only in areas receiving drainage from granitic rocks, and the acid neutralizing capacity of the river waters was in fact low in those areas. In Gifu, a declining trend was observed in some remote watersheds, where there was no clear relationship between the geology and the long-term trends. Since Niigata and Gifu receive the highest level of acid loading from the atmosphere in Japan, river water acidification in several watersheds may be attributable to the effects of the acid deposition. Other factors, such as hot spring drainage, changes in land use, and natural sea salt deposition, cannot adequately explain the acidification phenomena observed in this study.

Keywords

River water Acidification Acid deposition Acid neutralizing capacity Geology 

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Hiroki Matsubara
    • 1
    • 4
  • Shingo Morimoto
    • 2
  • Hiroyuki Sase
    • 1
  • Tsuyoshi Ohizumi
    • 1
    • 5
  • Hiroshi Sumida
    • 3
  • Makoto Nakata
    • 2
  • Hiromasa Ueda
    • 1
  1. 1.Ecological Impact Research DepartmentAcid Deposition and Oxidant Research CenterNiigataJapan
  2. 2.Graduate School of Science and TechnologyNiigata UniversityNiigataJapan
  3. 3.Gifu Prefectural Research Institute for Health and Environmental SciencesGifuJapan
  4. 4.Horiba, Ltd.KyotoJapan
  5. 5.Niigata Prefectural Institute of Public Health and Environmental SciencesNiigataJapan

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