PFOS/PFAS Future LOR Requirements
Recent feedback in Europe is that the industry is seeking PFOS LORs down to 0.0001µg/L. These new trace levels present a new range of challenges primarily about managing background and keeping a pristine sampling and laboratory environment however, with good systems and control these limits are achievable.
This newest method developed and validated in Australia takes a further step in reducing the LORs while at the same time building in strong control to avoid carryover and potential false positives. This method is designed for marine water and surface or ground water samples that are not expected to contain PFOS/PFAS at levels above 0.1µg/L.
Method and LOR Information
ALS METHOD CODE
- EP231-ST (12 analytes)
- EP231X-ST (28 analytes)
LIMITS OF REPORTING (LOR)
- 0.0003 to 0.01 µg/L (see overleaf)
METHOD OF REFERENCE: In house
Western Australia Interim Guidelines on the Assessment and Management of PFAS
In February 2016, the WA Department of Environment Regulation released an interim Contaminated Sites guideline on the Assessment and management of PFAS which included some very good guidance (see section 5.2 – link to the site follows). https://www.der.wa.gov.au/images/documents/your-environment/contaminated-sites/guidelines/Guideline-on-Assessment-and-Management-of-PFAS-.pdf
The Interim Screening levels for PFOS for Freshwater to a species protection level of 99% is 0.00023ug/L. This limit is still slightly below the new ALS LOR of 0.0003ug/L, however ALS will be targeting this in future development projects.
Other Australian Guidance
The Department of Defence in Australia issued an interim screening criteria in May 2015. The drinking water limits in this guidance are fairly typical at 0.2µg/L for PFOS and well above the low level or even standard ALS methods. The key in this guidance is that there are limits set at 0.65ng/L or 0.00065 µg/L for PFOS. This water protection limit is not about drinking water but more about protection of human health via seafood consumption. The Maximum Permissible Concentration is not about direct toxicological effects but designed to be used where seafood is caught for consumption. The new ALS method provides a PFOS LOR at approximately half of this limit.
Other EU Guidance
The EU Inland water quality standards have similar low limit of 0.65ng/L as an annual average. Other surface waters have an even lower limit of 0.13ng/L (0.00013µg/L) as an annual average to ensure the long term quality of the aquatic environment. If these sort of annual averages are the future in Australia then it is reasonable to assume that some samples will need to be tested down to limits of 0.0001 or even 0.00005µg/L otherwise an average result at these limits will not be possible.
Currently the lowest LOR available globally at ALS is 0.00009 µg/L for PFOS in the EU, albeit additional chemicals are currently being added to this method. This provides a methodology and experience for ALS to further lower these LORs should this become a requirement in Australia.
PFAS analysis in water for the Global Monitoring Plan of the Stockholm Convention