Esterification products of dihydrofuran-2,5-dione, C16-24 (even numbered) alkenyl with propane-1,2,3-triol and propane-1,2,3-triol oligomers

Endpoint summary

Additional information

Abiotic degradation; Hydrolysis

In accordance with column 2 of REACh Annex VIII a hydrolysis study does not need to be conducted if the substance is readily biodegradable or highly insoluble in water. The test item is a complex mixture for which the test guidelines for hydrolysis are not recommended. This is not only because components could have different hydrolytic rates but also hydrolysis products can be analytically indistinguishable from the starting components. The water solubility of the test item as a whole was expected to be loading rate dependent but for some of the components it was expected to be very low. Therefore, the test solution concentration required that would dissolve all the components would be impractically low in order to perform the test and a sufficiently sensitive analytical method was not available. Overall, these issues would make hydrolysis testing unfeasible. The main functional groups in the components of the test item are esters. Although esters usually readily hydrolyze, especially in alkaline conditions, some components of the test item may have a reduced hydrolytic potential due to them being essentially hydrophobic. An assessment of hydrolysis potential was obtained through the computer estimation programme Episuite v 3.12 using a MW of 1433. The half-lives of 76.932 days and 2.106 years were obtained for pH 8 and 7 respectively.

Biodegradation

A study was performed to assess the ready biodegradability of the test item in an aerobic aqueous medium. The method followed was designed to be compatible with OECD TG 30IB (CO2 Evolution Test) referenced as EC Method C.4 -C and US EPA Fate, Transport, and Transformation Test Guidelines OCSPP 835.3110 (Paragraph (m)). The test item, at a concentration of 10 mg Carbon/L, was exposed to activated sewage sludge micro-organisms with mineral medium in sealed culture vessels in the dark at approximately 21 °C for 28 days. The biodegradation of the test item was assessed by the determination of carbon dioxide produced. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes. The test item attained 6% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Adsorption/desorption coefficient (Koc)

One study is available. In this study, performed under GLP according to OECD TG 121 and EC Method C.19, the adsorption coefficient of the test item was measured using the HPLC screening method. The main components of the test item had no dissociation constants within the environmentally relevant pH range and therefore, the test item was tested with an approximately neutral mobile phase. The sample was prepared in tetrahydrofuran. The adsorption coefficient of the test item has been determined to be <17.8 (log Koc <1.25) for 19.7% of the test item and greater than 4.3E05 (log Koc >5.63) for 80.3% of the test item by percentage area normalization.