1,4-Butanediyl 3-(2,4-dimethyl-1,3-dioxolan-2-yl)propanoate

Endpoint summary

Description of key information

Non-readily biodegradable

Hydrolysis rate at 50 °C, after 5 days: 96 % at pH 4, 9.6 % at pH 7, 98 % at pH 9

Koc: 30.37 l/kg; LogKoc: 1.4825

Additional information

The ready biodegradability of the substance was assessed according to ASTM Guideline E 1720 -01, which is similar to OECD Guideline 301B. The test substance in a mineral medium was inoculated with the domestic activated sludge for 28 days under aerobic conditions.  During this period the biodegradation of the test substance was determined on the basis of CO₂ production. CO₂ evolution was determined on the days 0, 3, 7, 10, 14, 17, 20, 24, 28. Concurrent blank (medium and inocolum) and reference (dextrose, medium and inocolum) run in parallel. The substance recorded a biodegradability of 43.43 % on day 28. According to the ASTM E1720: the method requirement for Readily Biodegradability is a minimum of 60 % organic carbon conversion measured via CO₂ evolution achieved in a 10 day window after passing the 10 % biodegradation threshold. Based on the afore mentioned requirements and the OECD301 classification criteria, the test substance can be considered as non-readily biodegradable since it did not reach the pass level for ready biodegradability.

The hydrolysis of the substance was evaluated based on data on Similar Substance 01. Justification for Read Across is given in Section 13 of IUCLID.

The similar substance appears to be hydrolytically stable at pH 7 while at pH 4 and pH 9 it could be hydrolysed by 96 % (at 50 °C, after 5 days) and 98 % (at 50 °C, after 5 days) respectively. Further investigation, showed that the half-lifes of the substance are as follows: at pH 4, 25 °C: 12 days; at pH 7, 25 °C > 1 year; at pH 9, 25 °C: 12 days. Envrironmental conditions suggest that the substance woud be exposed to pHs raning from values close to neutral pH to slightly basic pH values). The hydrolysis results suggest that an increase of pH value from 7 to 9 have a great impact on the hydrolytic behaviour of the substance. Therefore, in neutral pHs the substance is considered to be very stable in contrast to basic pHs that the substance presents a half-time of 12 days. In combination with the biodegradation test (where the pH is usually ≈7.5) results, the substance is expected not to hydrolyse or to readily biodegrade in neutral pHs.

The adsorption coefficient (Log Koc) of 1.4825 and the LogPow of 1.9 suggest a low potential for adsorption to soil and sediment.

The substance is thus expected to be present in the water phase and not the soil one, and thus available for the aquatic organisms. Due to the non-readily biodegradability and the hydrolytic stability the substance is expected to be present in the aquatic environment as is.