Urban geochemical contamination of high conservation value upland swamps, Blue Mountains Australia

Upland swamps of the Blue Mountains are unique and legislatively protected peat swamp communities. This study investigated water chemistry of surface waters from seven Blue Mountains Upland Swamps (BMUS), four within urbanised catchments and three from naturally vegetated catchments. The purpose of the study was to investigate any ionic contamination from urban development. Water chemistry of non-urban BMUS was acidic (mean pH 4.7) and dilute (mean EC 26.6 μS/cm) and dominated by sodium and chloride ions with most other major ions at low concentrations, often below detection limits. In contrast, urban BMUS had higher pH (mean 6.6) and salinity (mean 153.9 μS/ cm) and were dominated by calcium and bicarbonate ions. The results of this study support the hypothesis that urban concrete contamination is modifying the geochemistry of urban BMUS. Further research is required to investigate ecological implications of the contamination and also to explore measures to protect such sensitive wetlands of high conservation value from urban development.