PFAS, Perfluorooctane Sulfonic Acid (PFOS)

PFOS (Perfluorooctane Sulfonic Acid) is a legacy PFAS compound used in firefighting foams, stain repellents, and waterproofing sprays. Although phased out in many countries, PFOS remains one of the most persistent and bioaccumulative environmental contaminants, detectable in human serum decades after use.

PFOS exposure is linked to liver toxicity, thyroid dysfunction, immune suppression, and carcinogenic potential. It interferes with lipid metabolism by increasing ApoB-containing lipoproteins and decreasing HDL, contributing to atherosclerosis and elevated cardiovascular risk. PFOS also suppresses immune function, reducing antibody response to vaccination and increasing infection susceptibility.

Endocrinologically, PFOS alters thyroid hormone transport proteins (TBG, albumin), leading to disrupted thyroid homeostasis and metabolic imbalance. It has also been implicated in hepatic steatosis, altered glucose metabolism, and oxidative stress pathways that accelerate vascular aging.

• Firefighting foams (AFFF): Historically used at airports and industrial facilities.

• Consumer products: Water-, oil-, and stain-resistant coatings in textiles and packaging.

• Food chain: Bioaccumulates in fish, meat, and dairy from contaminated water or soil.

• Indoor dust: Emissions from treated materials and older consumer products.

• Water filtration: Reverse osmosis or activated carbon filtration systems reduce PFOS effectively.

• Diet: Prioritise unprocessed foods; reduce intake of animal fats where PFOS tends to accumulate.

• Detox support: Optimise antioxidant intake (vitamin C, selenium, glutathione precursors) to mitigate oxidative damage.

• Clinical follow-up: Reassess PFOS levels annually; monitor cholesterol, liver enzymes, and thyroid function.

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