Hexafluoropropene, oxidized, oligomers, reduced, fluorinated

Endpoint summary

Additional information

Due to its chemical and physical properties, if GALDEN LMW is released into the environment the main compartment of distribution is the expected to be the atmosphere.

Galden LMW is characterized by a high Henry Law’s constant of 1.4 - 2.1 x 10E7 Pa m3 /mol a and low water solubility of 0.47 mg/L, indicating that the product tends quickly to volatilize from water reaching the atmospheric compartment. 

 

Basing on the experimental Log Kow = 5.58 and the estimated Log Koc = 3.74, a certain affinity for organic matter is expected, anyway, according to modelling estimation, when emitted to the environment practically 100% of the substance is expected to distribute to the atmospheric compartment at every degree of complexity of the model (Level I, II and III), while distribution to water, soil and sediment is expected to be negligible.

 

Experimental distribution studies were conducted in sediment-water-air systems. The studies were not performed according to standardized methods but methods and results are well documented and results provide information on the behavior of GALDEN LMW when spiked directly to the sediment.

In both the reported studies, no significant amount of the spiked GALDEN LMW remained into the sediment at the end of the tests, no residual substance was found in the water phase while a certain amount was found in the headspace air.

In both the studies the mass balance was not complete. By the end of the experiment a large amount of the Galden LMW was lost from the test system, either due to volatilization of the test substance during the setup of the experiment, or due to the fact that the test system was not hermetically closed during the test period.

The media distribution test results are consistent with the analytical results reported during the ecotoxicological evaluation of GALDEN LMW in the aquatic compartment.

OECD Guideline-conform studies have been conducted in order to define the acute toxicity of GALDEN LMW to algae, aquatic invertebrates and fishes and the long-term toxicity to aquatic invertebrates. The study protocols and systems were designed with the scope of limiting the losses of GALDEN LMW from water to the air. Nevertheless, under all the studies a high decrease in test item concentration in water has been observed during the exposure period and those analytical results have been ascribed mainly to losses for volatilization occurred during handling and exposure.

 

As other fluorochemical products GALDEN LMW is not expected to undergo significant biodegradation in any of the environmental compartments.

No experimental data are available for hydrolysis in water but, since GALDEN LMW does not contain any functional group associated with hydrolysis properties at relevant environmental conditions, and due to the presence of carbon-fluorine bond which is the strongest bond in organic chemistry (O’Hagan, 2008) it can be concluded that hydrolysis is not a relevant degradation mechanism for GALDEN LMW.

In the atmosphere, which is the main compartment of distribution, the lifetime of GALDEN LMW has been estimated to be ca. 800 years (Young et al., 2006).

 

Due to the low water solubility and high tendency to volatilize of GALDEN LMW, the standard bioaccumulation study on aquatic organism through water exposure is not feasible. Additionally, Galden LMW is not expected to bioaccumulate in aquatic species, as due to its high Henry constant and low water solubility, Galden LMW has the strong tendency to volatilize from the aqueous phase. Furthermore, there is no direct or indirect exposure of Galden LMW to the aquatic environment during the manufacturing process or the identified uses.

In accordance with its high tendency to partition into the air compartment, bioaccumulation in air-breathing organisms is to be addressed. Screening for bioaccumulation potential in air-breathing organisms can be done based on the Kow and Koa values. The cut-off values currently accepted as indication of bioaccumulative properties are log Koa≥5 AND log Kow≥2. As Galden LMW has a log Koa of 0.87, bioaccumulation of the substance is not anticipated.