The Tonalli River Catchment, a tributary at the southern end of Lake Burragorang, in the Greater Blue Mountains World Heritage Area1 (NSW), was studied to evaluate the spatio-temporal distribution of pollutants from the Yerranderie silver-lead-zinc mine site, abandoned in the late 1920s. Sediment cores were collected in the mouth of the Tonalli River and surface sediment samples were collected in the Tonalli River. The concentrations of Pb, As, Zn, Cu, Cd, Hg and Ag in the sediments were analysed by ICP-MS and ICP-AES techniques. Variability of pollutant input into Lake Burragorang through time was established through 210Pb dating of the core sediments. Published records of rainfall and bushfire data were used to discuss the analytical results and it was established that historically, metal concentration in the sediments, are higher in correspondence with heavy rainfall periods while spatially, metal concentrations decrease with distance downstream of the mines.
1. The Greater Blue Mountains Area (GBA) was established in December 2000 and consists of 1.03 million ha of mostly forested landscape on a deeply-incised sandstone plateau 60-180km inland from central Sydney. The site comprises eight protected areas in two blocks separated by a transportation and urban development corridor. Technically speaking, either the Yerranderie mine-site or the Warragamba catchment areas (including Lake Burragorang) are not included in the WHA. However our study site plays a very central role in the southern section of the WHA and has similar features. The GBA-site is particularly noted for its wide and balanced representation of Eucalyptus habitats including wet and dry sclerophyll, mallee heathlands, as well as localised swamps, wetlands, and grassland. Ninety Eucalyptus taxa (13% of the world's total) occur in the Greater Blue Mountains. The sites hosts several evolutionary relic species; such as the Wollemi pine, which have persisted in highly-restricted microsites.