Polyorganosiloxanes (Silicones) in the aquatic environment of the Sydney region

Abstract

Polyorganosiloxanes, or silicones, common ingredients in a range of modern domestic and industrial formulations, have been detected in waters, surface microlayer samples, sewage discharges and estuarine sediments collected from the coastal zone near Sydney, New South Wales. High concentrations in sewage sludge (>100µg Si g^-1) are not reflected in waters receiving a sewage discharge. However, the high affinity of hydrophobic silicones for large-surface-area clayey sediments leads to wide variability within a single waterbody, indicative of localized inputs. Furthermore, the fine structure of organosilicon sediment-depth profiles affords an excellent chemical indicator of a 1950 horizon, the approximate date of introduction of these compounds to Australia.