ITRAX Core Scanner Capabilities Combined with Other Geochemical and Radiochemical Techniques to Evaluate Environmental Changes in a Local Catchment, South Sydney, NSW, Australia

Abstract

In this study, geochemical and radioanalytical techniques are used together with the ITRAX core scanner to reconstruct the environmental history of Mill Creek catchment, located on the south-western fringes of Sydney. This ITRAX capability study was undertaken to investigate environmental changes in a local catchment which incorporates a nuclear research reactor, a small legacy nuclear waste burial ground, extensive new housing developments, a large rubbish tip, as well as quarries. This catchment changed from being near pristine in the 1950’s to an extensively developed catchment with wide ranging land uses. This rapid development has led to silting up near the mouth of the creek, and there is also evidence of periodic siltation triggered by catchment disturbance from local bushfires, associated with peaks in magnetic susceptibility. The sedimentary environment changed from a creek system to a mangrove swamp and saltmarsh. Changes in Cu, Zn and Pb distributions over the last 60 years suggest an anthropogenically-driven input, although concentrations measured by WD-XRF indicate that the level of urbanisation is lower in the study area than in many of the more industrialised and urbanised neighbouring catchments of Sydney estuary and Botany Bay. The activities of ^239 + 240Pu and ²⁴¹Am in the sediment are below detection limit, which strongly suggests that the legacy nuclear waste has not entered the creek system.