Underground tank abandonment, vapour intrusion, duty to report, PFAS (per and polyfluorinated alkyl substances), groundwater, St Marys NSW.
A series of underground tanks required validation after being abandoned insitu by a remediation contractor. Validation could not be achieved given the detection of significantly high concentrations of petroleum and chlorinated compounds that were found in localised soil samples, and subsequent soil vapour and groundwater. The contamination was significant to warrant notification to the NSW EPA under Section 60 of the CLM Act 1997 (NSW) given the potential health risk to indoor workers from vapour intrusion of volatile petroleum and chlorinated compounds.
Historical information also showed the use and storage of Per- and Poly- Fluorinated Alkyl Substances (PFAS) in firefighting training at the site, requiring additional assessment to examine if PFAS has contaminated soils and groundwater.
A Sampling and Analysis Quality Plan (SAQP) was prepared for approval by the NSW EPA. Subsequent testing showed a low risk of vapour intrusion into building overlying the chlorinated vapour plume and the NSW EPA determined that the contamination did not require regulation under the CLM Act. It was concluded that contamination is to be addressed under planning laws for any future site development works.
