Lake Burragorang, the focus of this thesis, is the main water supply source for the large population of Sydney and is a major source for the Blue Mountains residents. This study was aimed to evaluate the distribution of heavy metals and their speciation in sediments of Lake Burragorang. The principal focus is on the study of heavy metal pollution and their bioavailability to the aquatic system. Five-step sequential extraction procedure was employed to assess different geochemical forms of certain metals in sediment grabs of Lake Burragorang. This is the first study to report metal speciation data for Lake Burragorang sediments. No significant spatial variations were observed in the speciation trends. The variation in metals and nutrients in the sediments with age was established and has been compared with published historical record, rainfall records and bushfire data. / Master of Engineering (Hons)