千葉県北部における酸性雨の地域的特性について(3) : 1996年度観測結果

概要

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In order to clarify the regional characteristics of acid rain in Chiba Prefecture, the data of precipitation which were obtained during the period from April 1996 to March 1997 with the aid of the environmental monitoring volunteers of the Institute of Environmental Studies of Keiai University have been analyzed. The results of the analyses are summarized as follows : 1) The observation sites where the mean pH values of rain samples collected every rain event in the warm season are more than 5.5 are distributed in the northeastern and the southwestern parts of the area investigated. 2) The maen values of NO_3^-/nss-SO_4^<2-> concentration ratio (N/S ratio) decrease with distace toward the east, and in the northeastern part of Chiba Prefecture, the ratio less than 0.3 are observed in both the warm and the cool seasons. 3) The pH value shows high negative correlation with fractional acidity ([H^+]/([nss-SO_4^<2->]+[NO_3^-]) in the warm season. The relation between the pH value and the fractional acidity (A) can be expressed by follows. pH=-2.69A+5.69 r=-0.71 4) The mean value of NH_4^+/nss-Ca^<2+> concentration ratio increase with the distance toward the west of the study area, in both the warm and the cool seasons.
敬愛大学・千葉敬愛短期大学の論文