Rainwater composition at two BAPMoN regional stations in SE Australia

Abstract

Analysis of 5 years of rainwater composition data from two BAPMoN Regional stations in southeastern Australia shows both sites to be relatively little influenced by anthropogenic sulfur and nitrogen emissions. Long-term average depositions of non-sea-salt (nss) sulfate, nitrate and ammonium were all < 7.4 mmole m^-2 yr^-1 at both sites, which according to Galloway (1985) classifies these sites as “remote continental”, or relatively unperturbed. Consistent with this, the long-term mean pH of rainwater at both sites was > 5, though it must be acknowledged that the sampling protocols used in the BAPMoN network are such that weak organic acids will be lost from the samples prior to analysis. No secular trends in ion concentration or deposition were discernible over the 5-year data record for any of the species determined.