Chemistry of the Castlereagh River, New South Wales

Abstract

Preliminary studies of the chemical characteristics of the Castlereagh River were made in 1973. The concentrations of the major ions vary considerably with distance from the head of the river and this variation shows a marked correlation with the geology of the catchment area. The order of dominance for ions within the system was found to be Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ and HCO₃^- > Cl^- > SO₄^2- for the main river, and creeks in the eastern catchment gave Mg²⁺ > Ca²⁺ > Na⁺ > K⁺ and Cl^- > HCO₃^- > SO₄^2-. The relative amounts of the dominant chemical species are discussed and suggestions are made for the possible origins of specific components.