Perfluorinated chemical testing (PFAS - PFOS)
Sullivan Nicolaides Pathology is now testing for the perfluoroalkyl substances including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).
These compounds and their salts have been used commercially either directly, such as in aqueous fire-fighting foams, or as dispersants in polymer manufacture (e.g. TEFLONTM), or as chemical intermediates in the production of surface coating products such as the earlier formulations of SCOTCHGUARDTM. Both PFOS and PFOA are very stable and can remain intact in the environment for many years, accumulating in the food chain and water supply. Concerns around the persistence of these compounds have prompted their phase-out by most manufacturers.
In some parts of Australia, the use of specialised fire-fighting foams prior to recognition of their environmental impact, has left considerable PFOS contamination in local groundwater. Local residents around contamination spots may have blood levels 5 to 10 times normal. Recently, the US Environmental Protection Agency lowered the safe drinking water level to below 70 parts per trillion. For people living at these sites, it is advisable not to drink water derived from the groundwater and also to avoid eating animals that have been raised or caught in the area.
Test collection information
Sample type: 2 x Dedicated SST (unopened, no aliquots)
Minimum volume: 8ml blood
Transport: Ambient i.e. esky with ice brick (not frozen)
Test performed: Weekly – results available within 2 weeks of receipt of specimen
Cost: $500 (plus GST)
Image courtesy of RAAF Fire Service
|perfluorinated||Having all hydrogen atoms not associated with a functional group replaced with fluorine atoms.|
|polyfluorinated||A compound bearing multiple fluorine atoms. In the context of PFAS, typically refers to highly fluorinated, not perfluorinated compounds (i.e. some hydrogens remaining).|
|PFAAs||Perfluorinated alkyl acids. Typically any perfluoroalkyl incorporating a sulfonic, carboxylic or phosphonic acid head group, or the conjugate base of these. Includes both PFOS and PFOA.|
|PFASs||Perfluorinated alkyl substances or perfluoroalkyl substances. Generic term for all perfluorinated compounds regardless of functional group.|
|PFC||Perfluorinated compounds. Used in earlier literature. Discouraged from use due to confusion with simple perfluorocarbons as used in refrigerants etc.|
|PFCAs||Perfluorinated carboxylic acids. Includes PFOA.|
|PFSAs||Perfluorinated sulfonic acids. Includes PFOS.|
Table – Commonly encountered nomenclature for Perfluorinated Alkyl substances
A correlation has been noted between PFOS levels in pregnant women and low birth weight infants. In adults, elevated levels of PFOS have been associated with altered thyroid hormone concentrations as well as increased cholesterol levels. In animal studies, PFOS at very high concentrations can cause cancer, stunted growth, endocrine disruption, and neonatal mortality.
PFOS levels in pooled human sera from South East Queensland, Australia obtained from de-identified surplus pathology samples.
Three age groups were analysed; A 0-4 years, B 5-15 years and C >16 years.
Highest levels were seen in the oldest age group, reflecting past exposure to higher environmental levels.
Some areas in the USA have had their drinking water contaminated by PFOA. Long term studies of these populations have shown probable links between PFOA exposure and ulcerative colitis, high cholesterol, thyroid disease, testicular cancer and kidney cancer. Both PFOS and PFOA are still being studied and no clear picture exists as to what constitutes dangerous exposure.
The perfluorinated alkyl acids PFOS and PFOA
|Perfluorooctanoic Acid (FPOA)||Perfluorooctane Sulfonate|