Abstract
From June 1996 to August 2002, some ion concentrations in one-storm precipitation were measured at USP (the University of SHIGA Prefecture) which is adjacent to Lake BIWA. Using these concentrations the effect of the lake on ion concentrations in precipitation was estimated.
In conventional methods, effects of sea-salt have been estimated by using Na+ concentration and ratios of pollutant concentration to Na+ concentration. However, in the adjacent area to Lake BIWA it has been observed that the ratio of Cl-to Na+ in precipitation is lower than the sea-salt. So, it is suggested that chlorine-losses may have been observed and that Na+ is not only from sea-salt but also from lake-salt. Then the author attempted to estimate the sea-salt effect and lake-salt effect on ion concentrations by using Mg2+ and Na+ in precipitation. In this situation it was assumed that Mg2+ and Na+ are only from sea-salt or lake-salt and not from soils or human activities.
It was shown that miscellaneous SO42- (other than from sea-salt or lake-salt) was 10 to 20% less than conventional non-sea-salt (nss) SO42-.
