Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability

The performance of a hydrolysis as a function of pH test is scientifically not justified as the test item is practically insoluble in water.

Biodegradation

Biodegradation in water: screening tests

1,1'-(1,1,2,2-tetramethylethylene)dibenzene was assessed in a closed bottle test in accordance with OECD guideline 301 D and EU method C.4 VI. The test item was exposed to activated sludge from an aeration tank for 28 days. Under the test conditions the percentage biodegradation of the material reached a mean of 0.2 % based on ThODNH4. Thus, the test item has to be considered as not ready biodegradable.

Screening tests on biodegradation in soil as well as water and sediment is considered scientifically unjustified. 1,1'-(1,1,2,2-tetramethylethylene)dibenzene is practically insoluble in water. Furthermore, low exposure is guaranteed, as no sludge application from STP on soil will be done and aerial deposition is negligible.

Bioaccumulation

Direct and indirect exposure of the test item to water is highly unlikely. Further, the test item is practically insoluble in water. Therefore, 1,1'-(1,1,2,2-tetramethylethylene)dibenzene was considered to have no bioaccumulation potential. The performance of a test for bioaccumulation in aquatic species, preferably fish, is scientifically unjustified. Therefore, the bioaccumulation potential of the test item was estimated using QSAR models.

Using VEGA v1.1.4 model CAESAR v2.1.14 the BCF value of the test item was calculated to be 999 L/kg. Using T.E.S.T. v4.2.1 the BCF value of the test item was calculated to be 1275 L/kg. The substance is within the applicability domain of both model. Thus, the estimations are considered to be accurate. For risk assessment purposes as worst case scenario the value of 1275 L/kg was chosen as a key value.

Transport and distribution

The adsorption coefficient (Koc) on soil and sewage sludge of 1,1'-(1,1,2,2-tetramethylethylene)dibenzene was assessed according to EU method C.19 and OECD guideline no. 121 using the HPLC method. Based on the retention time measured for 1,1'-(1,1,2,2-tetramethylethylene)dibenzene (8.25 min), the log Koc was estimated to be 4.20 ± 0.007 (95 % confidence interval) corresponding to a Koc of 15968 ± 254.8 (95 % confidence interval) at 25°C.