1-[difluoro(trifluoromethoxy)methoxy]-1,2,2-trifluoroethylene

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

ADDITIONAL INFORMATION SUPPORTING DATA WAIVING

At the required tonnage band of registration, the following information are required to be provided: Adsorption/desorption screening test. The OECD Test Guideline 121 and EU method C.19. “Adsorption/desorption screening test “ describe an experimental method using HPLC for the estimation of the adsorption coefficient Koc in soil and in sewage sludge. The test substance is injected in the column packed with cyanopropyl solid phase containing lipophilic and polar moieties. As a result of partitioning between mobile and stationary phases the test substance is retarded and the Koc is determined basing on the retention time of the substance. The Adsorption/desorption screening test according to OECD Test Guideline 121 is not technically applicable to MOVE 3. In fact, the method described in the mentioned test guidelines is based on the same principle as the OECD Test Guideline No. 117 “Partition Coefficient (n-octanol/water), HPLC Method”. The HPLC method was tried to be used for the determination of Kow according to the OECD guideline No. 117. The method was tested but proved not applicable since MOVE3 is not detected using UV detection at 210 nm, Refractive Index detection, Evaporative Light Scattering detection or Mass Spectrometric detection. For this reason the Adsorption/desorption screening test is not technically feasible for MOVE 3. It should be noted that also the feasibility of the adsorption/desorption measurement according to the batch equilibrium method (OECD Test Guideline No. 106 and EU method C.18), that according to REACH Annexes IX may be required for the higher tonnage band of registration, is questionable. In fact high volatilization of the substance from water was observed, and this is expected to prevent the achievement of a stable concentration in water during the test. Moreover analytical issues may occur during the quantification of MOVE 3 concentration in water. In fact, analytical difficulties were observed when the analytical method for quantification in water was tried to be applied in ecotoxicological test. The analytical difficulties observed in the ecotoxicological study were ascribed to the MOVE 3 physical and chemical properties (poorly soluble, extremely volatile liquid with a boiling point of 19.5°C) and since all the feasible measures for improving the analytical performance were applied unsuccesfully the test was considered technically unfeasible. As the adsorption/desorption measurement according to the batch equilibrium method (OECD Test Guideline No. 106 and EU method C.18) requires several analytical measurements in water the same analytical issues observed in ecotoxicological study are anticipated to occur in the Adsorption /desorption test. For this reasoning the adsorption/desorption measurement according to the OECD Test Guideline No. 106 and EU method C.18 is expected to be not feasible.

Reason / purpose for cross-reference:

data waiving: supporting information

Description of key information

No Koc value is available as the test is technically unfeasible.

Additional information

Because of the physical and chemical properties of MOVE3 the experimental determination of Koc is not technically feasible.

However, based on the information available MOVE 3 is not expected to have a significant potential for adsorption. In fact during the attempt to develop an analytical method for the quantification of MOVE3 in octanol (CRL 2017), rapid volatilization of the substance from octanol was observed. Tendency to rapid volatilization from octanol was also observed in the Kow study performed in 2020 (PROCESSIUM 2020) where specific measures were put in place for avoiding volatilization.

As the partition coefficient octanol-water provides indications on the tendency of a substance to adsorb to organic matter it can be concluded that in a system organic matter-air MOVE3 would not have significant tendency to distribute to organic phase and it would rather distribute to air.