Relationship between Components and pH of Rainwater at Municipal Outskirts

• Published in: Eisei kagaku Vol. 36; no. 3; pp. 234 - 242
• Main Authors: SAYATO, YASUYOSHI, NAKAMURO, KATSUHIKO, MORITA, HIROMI, GOTO, RIKA
• Format: Journal Article
• Language: English; Japanese
• Published: The Pharmaceutical Society of Japan 1990
• Subjects: acid rain; acidification; ionic component; pH; rainwater
• ISSN: 0013-273X
• DOI: 10.1248/jhs1956.36.234

In order to elucidate a relationship between ion components and pH of rainwater, analysis of major ions in rainwater collected in Hirakata City located between Osaka and Kyoto were carried out during a period from May, 1985, to June, 1989. Characteristics of ionic components in rainwater and factors effecting pH of rainwater were discussed by using the data obtained. In this study, average pH value during four years was estimated to be 4.62 (n=214). Comparatively lower pH of rainwater was revealed in winter season. The pH value of rainwater tended to terminate to be pH 4.62 with increasing the amount of rainfall. The relationship between the amount of rainfall (x : mm) and EC (y : μS/cm) was found to be y=bx-a. Comparison of anionic and cationic ion ratio in rainwater demonstrated that NO3- was the largest share in anions and each NH4+ and Na+ was the lowest one in rainwater showing below pH 4.62. It is considered that acidification of rainwater may be caused by the ratio of anionic and cationic components in rainwater.