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.

Ready biodegradation

Biodegradation in water: screening tests

A study was performed to determine the potential for ready biodegradation of the test item by the carbon dioxide (CO2) evolution method following OECD 301B, adopted in 1992. The CO2 released upon biodegradation of the test item and the reference substance sodium benzoate was measured. Two blank controls (containing only inoculum) and a toxicity control (containing inoculum, reference and test substances) were established to account for background CO2 production and toxicity of the test item, respectively. All validation criteria were fulfilled. The sodium benzoate controls had degraded > 60 % at day 8. Based on the CO2 analysis, there was no biodegradation observed for the test item within the 28 days. The degradation of the test item was therefore less than the minimal guideline demand of 60 %.Therefore the test item is considered to be not readily biodegradable.

Biodegradation in water and sediment: simulation tests

Biodegradation in soil

Direct and indirect exposure of the test item to water, sediment and soil is unlikely. The test substance is practically insoluble in water. In addition, low exposure is guaranteed, as no sludge application from STP on soil will be done and aerial deposition is negligible. Thus, simulation testing for biodegradation in water, sediment and soil was considered not scientifically justified.

Bioaccumulation

The bioaccumulation factor for the main component (dimer) of the test substance was estimated to be 1112 L/kg wwt using the software EPIWIN v4.11, BCFBAF v3.01.

Transport and Distribution

The adsorption/ desorption coefficient Koc of the test item was assessed using an HPLC method according to OECD 121, adopted in 2001. 15 µL of the test item solution (4.3 mg/L mobile phase) were injected onto the column. The retention time of the test item was determined in duplicate and the capacity factor k was calculated. The assay was performed with pH 7.2 at 35°C. 6 reference compounds were included according to the guideline. The calculated log Koc was estimated to be 6.5 at pH 7.2 (PCKOCWIN). This corresponds to a Koc = 3.23 x 10E06.The experimentally derived logKoc which was deduced from the capacity factor k' using a calibration plot of log k' versus log Koc of the reference compounds, was6.49 with pH 7.2 at 35°C. This corresponds to a Koc = 3.1 x 10E06. Based on this result it is estimated that the test item is not water soluble and it may adsorb to organic material.