A Review on Environmental Occurrence and Toxicity of Perfluorooctanoic Acid and Its Selected Short-Chain Analogs—Perfluorohexanoic Acid and Perfluorobutanoic Acid

In this review, the occurrence of perfluorooctanoic acid (PFOA) in the environment and human surroundings, as well as its toxic action and its selected short-chain analogs—perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid (PFBA)—has been described. These substances belong to a group of polyfluoroalkyl substances (PFASs) that are widely represented in various compartments of the environment, including the air, water and soil. They are also present in food, drinking water and dust, which are the main sources of exposure for humans to these substances. Due to their physico-chemical properties, PFASs are resistant to degradation in the biosphere and therefore effectively accumulate in biota, including humans. PFOA has been produced for decades, but due to its toxicity, it was subsequently replaced by PFASs with a shorter chain, including PFHxA and PFBA, whose presence in the environment, as well as risk of human exposure and toxicity, has been poorly investigated. It has been proven that PFOA has hepatotoxic and endocrine-disrupting activities, as well as prooxidative, immunotoxic, epigenetic and carcinogenic potential. Previously conducted studies have shown that PFHxA and PFBA are less toxic than PFOA; nevertheless, additional extensive studies should be conducted in order to determine the environmental and toxicological status of these compounds.