Abstract:
Core and surface sediments from the Tonalli River, a tributary of the artificial lake,
Lake Burragorang, in the Blue Mountains National Park, New South Wales, Australia, were
studied to evaluate the spatio-temporal distribution of pollutants from the Yerranderie silver-leadzinc
mine site, abandoned in the late 1920s. A sediment core was collected in the mouth of the
Tonalli River, at its junction with Lake Burragorang, and surface sediment samples were collected
in the Tonalli River and its tributaries. The concentrations of Pb, As, Zn, Cu, Cd, Hg and Ag in
the sediments were determined by ICP-MS and ICP-AES techniques. Temporal variability of
metal concentrations was established through 210Pb dating of the core sediments and compared
with published historical records, rainfall records and bushfire data. Metal concentrations in core
sediments showed an overall increase around the year 1950 as well as increases coincident with
heavy rainfall. Spatially, metal concentrations were up to 400 times the guideline limit around
mine sites but decreased rapidly with distance downstream of the mines.
