The determination of recent sedimentation rates has traditionally used radiochemical dating techniques
but, because of limited laboratory facilities and the costs of these techniques, alternative methods are
desirable. Information on sedimentation rates and sediment history can be obtained from anthropogenic
chemical components whose presence in sediments, especially near urban areas, can be used as markers
to assess their chronology. More than one marker, with a known date of introduction, should be used.
In this study, organosilicons first used in the early 1950s and tributyltin used in marine antifouling
paints from 1972 were examined in sediments from Lake Macquarie, NSW, to supplement the known
input of heavy metals from the lead-zinc smelter that has been operating at the northern end of the
lake since 1897. The most reliable data were obtained at sites where all three markers were present,
and use of these data allowed independent determination of the year of initial operation of a sewage
treatment works.