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PFAS Investigation: Not all PFAS is created equal

Per- and polyfluorinated alkyl substances (PFAS) contamination has generated substantial industry buzz, regulator involvement and community concern. Currently, there is significant focus on fire fighting training facilities due in part to high profile contamination reported at Williamtown (NSW) and Oakey (QLD) defence sites. PFAS contamination at these fire fighting training facilities resulted from historical use of fluorinated fire fighting foams (AFFF). However, other potential sources of PFAS contamination have been given little attention such as chrome plating plants where PFAS has been used as a mist suppressant.

Site investigations completed by Geo-Logix demonstrate that contamination from different PFAS sources present different contamination characteristics. This impacts the way PFAS contaminated sites are assessed and managed. To demonstrate the difference in contamination characteristics we have compared groundwater data from a site impacted from an AFFF source against that from a site impacted by a chrome plating plant source. This chart presents individual PFAS compounds as a proportion of detectable PFAS present in groundwater from these two different contamination sources.picture2As the chart demonstrates, groundwater analytical data from sites with an AFFF source indicates PFAS impact is dominated by perfluorooctane sulfonate (PFOS) and to a lesser extent perfluorohexane sulfonate (PFHxS). Other perfluorinated sulfonate compounds in the C4 to C10 carbon chain length range are present, albeit at lower concentrations. Perfluorinated carboxylic acids including perfluorooctanoic acid (PFOA) generally comprise a minor portion of the total PFAS identified (<15%).

PFAS contamination from AFFF is markedly different to PFAS contamination sourced from chrome plating plants. Our results have found the composition of groundwater contamination from chrome plating activities is upwards of 95% PFOS with trace amounts of PFOA and PFHxS.

The composition of PFAS in groundwater is affected by the fate and transport properties of the different PFAS compounds. However, this does not account for the significant difference observed between PFAS sources and demonstrates that not all PFAS contaminated sites are equal. While an AFFF source may result in a complex mix of higher and lower toxicity PFAS compounds, contamination from a chrome plating plant is dominated by PFOS, the most toxicologically important compound under investigation.

Geo-Logix provides high level advice on several PFAS impacted sites across Victoria, NSW and Qld. Contact Ben Pearce bpearce@geo-logix.com.au for further information.

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