Perfluorinated Compounds in the Australian Environment: Sources, Fate and Human Exposure

Perfluorinated compounds (PFCs) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are anthropogenic chemicals produced since the 1950’s for various commercial and industrial applications, including stain-proofing and polymer production. In the past 10 – 15 years PFCs have come under increasing scrutiny as apparently ubiquitous and persistent environmental pollutants. They have been found to accumulate in humans and wildlife. To date no conclusive evidence has been found linking PFCs to any adverse health effects in humans. However a number of toxicological responses have been reported in animals and in cell assays following exposure to these chemicals. The aim of this thesis was to obtain robust data regarding the presence of these compounds in the Australian environment, providing ‘baseline’ concentrations against which to assess in future the effect of product discontinuation and increased regulation. This thesis also aimed to assess the extent to which the Australian population is exposed to PFCs, and the potential sources of this exposure. This work contributes to the growing global database on PFCs in the environment, and lessens the knowledge gap with regards to the Australian environment, and more broadly the Southern Hemisphere in general. A complete investigation of all possible sources of PFCs in Australia, their environmental transport and fate would be impossible within the scope of a single PhD thesis. Instead several studies were undertaken to investigate a particular aspect of the broader issue. Human exposure was investigated in terms of daily intakes of the two most prominent PFCs, PFOS and PFOA. These were estimated for the Australian population using pharmacokinetic modelling. This provided average intake estimates of 0.80 & 1.5 ng/kg bw/day for PFOA and PFOS respectively (Chapter 2). Next, drinking water was investigated as a possible contributor to this exposure. Analysis of samples from 34 locations across Australia showed drinking water is most likely a small contributor to daily PFOS and PFOA intakes, accounting on average for around 2% (Chapter 3). However PFCs were present at trace levels, with at least one PFC being quantifiable in 76% of the samples. PFOS and PFOA were the most frequently detected with overall averages of 1.6 and 0.99 ng/L respectively, well below the provisional drinking water guidelines available internationally. Having established the presence of these compounds in drinking water, a next step was to examine their fate during water treatment. This was done to understand the behaviour of PFCs in state of the art water treatment facilities in Australia, their removal efficiencies, and the likelihood of any contamination stemming from the treatment process itself. PFCs were measured at two advanced water treatment plants throughout the various stages of treatment (Chapter 4). At one facility, with ozone oxidation and sorption processes operating, PFC concentrations remained relatively stable throughout treatment and were present in the finished water. At the second facility all the PFCs were rejected by the reverse-osmosis membranes and concentrated in the brine waste stream. This removed the PFCs from the finished water, but raised the issue of environmentally responsible management of this waste stream. Looking at the broader environment, a mixed media study of the Homebush area in Sydney was undertaken (Chapter 5). PFCs were measured in water, sediment, fish, oysters and bird eggs from the area. The lowest concentrations were found in sediment