Ammonium perfluorooctanoate APFO

Currently, there is concern about the use of ammonium perfluorooctanoate (APFO), also known as C8 , which is necessary for the manufacture of fluorinated plastics and elastomers in water. C8 is a perfluorinated anionic surfactant used as a dispersing agent in the polymerization and copolymerization of many fluoropolymers, including poly(tetrafluoroethylene) (PTFE), poly(vinylidene... 

Animal studies have shown that the ammonium salt of PFOA (ammonium perfluorooctanoate APFO) is well absorbed following oral and inhalation exposure, and to a lesser extent following dermal exposure. PFOA distributes primarily to the liver and plasma and may be detected in the blood stream after exposure. It does not partition to the lipid fraction or adipose tissue. PFOA is not metabolized and there is evidence of enterohepatic circulation of the compound. 

Lundin et al. [43] conducted a mortality study in a cohort of 3,993 highly exposed employees of an ammonium perfluorooctanoate (APFO) manufacturing facility. APFO rapidly dissociates to PFOA in blood. PFOA in serum was not associated with liver, pancreatic and testicular cancer or cirrhosis of the Uver. Exposure was associated (albeit inconsistently) with prostate cancer, cerebrovascular disease and diabetes. 

For decades, ammonium perfluorooctanoate (APFO, or C8) was an essential processing aid in the manufacture of fluoropolymers. As a polymerization aid it played a critical role in the polymerization of TFE and fluorinated comonomers used to produce PTFE, PEA (MFA), and FEP. It acted as an intermediate for the majority of fluoropolymers and was eliminated during the finishing steps. As produced solid phase fluoropolymers contained small amounts of C8 in the order of a few parts per million. Under a fraction of a percent of APFO was present in aqueous dispersion products. 

Adsorption of ammonium perfluorooctanoate (APFO) and ammonium de-canoate (AmDec) at the air-liquid interface was studied by Simister et al. [24] using surface tension and neutron reflection measurements. At the cmc, the areas oc-... 

Burkitt et al. [92] studied mixtures of ammonium decanoate (AmDec) and ammonium perfluorooctanoate (APFO) by the contrast matching SANS technique [56]. The proportions of the two surfactants in an ammonium chloride-ammonium hydroxide buffer at pH 8.8 and an ionic strength of 0.1 were varied. The mixed micelles formed were cylindrical in shape at APFO/AmDec ratios of 2 1, 1 1, and 1 2. The micelle appeared to have a diameter of 20 A and a length of 150 A. The authors proposed that the original ammonium perfluorooctanoate micelle, which also had a diameter of 20 A, expanded along the lateral axis to accommodate the decanoate chains (Fig. 7.8). At a 1 9 APFO/AmDec ratio, the micelles were found to be cylindrical but larger than those formed by ammonium decanoate alone. 

Ammonium perfluorooctanoate can be very toxic to aquatic organisms and may cause long-term effects in the aquatic environment. It may produce a milky appearance if released into surface waters. The 96 h lethal concentration (LC50) of APFO is 766 mgl for fathead minnows and 569mgl for bluegill sunfish. 

Note APFO Ammonium perfluorooctanoate APFN Ammonium perfluorononanoate AFFF Aqueous fire-fighting foam POSF Perfluorooctylsulphonyl fluoride... 

AFFF Aqueous film-forming foams (also aqueous fire-fighting foams) APFN Ammonium perfluorononoate APFO Ammonium perfluorooctanoate ECF Electrochemical lluorination, a process used to produce iluoiinated chemicals FP FluOTopolymer FT Fluorotelomer POSF PerfluorooctanesulphOTiyl iluraide PVDF Polyvinylidene fluoride... 

Ammonium perfluorooctanoate has been found to be persistent in the environment and to accumulate in wildlife and humans. Consequently, in the mid-2000s, fluoropolymer manufacturers began taking steps to abate environmental emissions and reduce and eliminate APFO from dispersion products. The industry reduced the usage in its products by 95%... 

Sakr O, Kreckmann KH, Green JW et al (2007a) Cross-sectional study of lipids and liver enzymes related to a serum biomarker of exposure (ammonium perfluorooctanoate or APFO) as part of a general health survey in a cohort of occupationally exposed workers. J Occup Environ Med 49(10) 1086-1096... 

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