reaction mass of mixed (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl) phosphates, ammonium salt

Endpoint summary

Additional information

A study conducted on Zonyl was used as a read across for The Notified Substance (TNS). Zonyl is representative of the composition of TNS. It is a comparable mixture of mono, bis, pyro/poly and trifluoroalkyl phosphates as ammonium salts but which varies in carbon chain length and percentage composition. The carbon chain length varies from 4-12+ i. e. the repeating unit F(CF2) m where m = 4,6,8,10,12+ though m=6 and m=8 dominate the composition on a per weight percentage. As such it is expected that certain properties can be read-across. In this case, the Zonyl surrogate was the test substance administered. Absorption of The Notified Substance (TNS) is expected to be very slow and insignificant by the oral and dermal routes of exposure. In a biopersistence screening study, no effects on mortality, clinical signs, or body weight were observed. Under the conditions of the test, administration of the test substance for 10 consecutive days resulted in limited absorption and retention of fluorine in the blood. There was some absorption and retention of fluorine in the liver, and levels of total fluorine in livers were higher than levels in the blood.

A study conducted on a compositionally similar analogue to TNS but where the counterion was lysine instead of ammonium was used as supporting read-across.TNS ammonium free was administered by oral gavage to male and female rats in a single dose of either 10 mg/kg or 30 mg/kg. Plasma concentrations of the mono, bis and pyro constituents were observed in both sexes at various time points after dosing indicating absorption. These constituents were distributed in plasma, fat and liver tissues of both male and female rats. In all tissues, the highest concentrations were for the bis phosphate constituent. In vivo metabolism was evidenced by the suite of metabolic products 6:2 FTCA, 6:2 FTUCA, PFBA, PFHxA, PFHpA and 5:3 FTCA as quantified in the plasma of both sexes. Plasma concentrations of 6:2 FTOH were not quantified, since they were lower than the limit of detection thus indicating that the rate of metabolism was faster than the rate of formation. A similar toxicokinetic study was performed for 6:2 FTOH dosed orally in male rats at 300 mg/kg. The observed concentrations of metabolites in the two toxicokinetic studies compare reasonably well when the plasma concentrations are normalised to the same oral dose. Thus TNS is readily hydrolysed to 6:2 FTOH in vivo and the alcohol is then subject to the well-known metabolic pathways leading primarily to formation of conjugation products along with minor yields of terminal carboxylic acids. Additional documentation provided within IUCLID supports the read across approach.