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Environmental fate & pathways

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Hydrolysis: Assessment of hydrolytic stability was carried out using Method C7 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).The kinetics of the study have been determined to be consistent with that of a pseudo-first order reaction as the graphs of log10 concentration versus time are straight lines. It has been observed that the rate of hydrolysis increases with an increase in pH. The hydrolysis pathway was anticipated to be base catalysed hydrolysis/cleavage of the test material at either of the two ester bonds. Therefore possible primary hydrolysis products may be, but not limited to: • Butanedioic acid • 2 -Propenoic acid, 2 -hydroxyethyl ester • 2-Propenoic acid • Butanedioic acid, mono 2-hydroxyethyl ester.

The determination was carried out using Method C7 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

The rate constant and estimated half-life at 25°C of the test material are shown in the following table:


Rate Constant (s-1)

Estimated Half-life at 25oC


2.72 x 10-8

295 days


5.13 x 10-8

156 days


4.14 x 10-6

46.5 hours

The estimated half-life at 25 oC 295 days (pH = 4), 156 days (pH = 7) and 46.5 hours (pH = 9) indicates that significant exposure to the parent compound in the environment over a long period of time is not of significant concern.


A study was performed to assess the ready biodegradability of the test material in an aerobic aqueous medium. The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 301B, "Ready Biodegradability; C02 Evolution Test" referenced as Method CA-C of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC), and US EPA Fate, Transport, and Transformation Test Guidelines OPPTS 835.3110 Paragraph (m).

The test material attained 2% degradation after 1 day, 18% degradation after 2 days, 62% degradation after 12 days and 70% degradation after 28 days. Examination of the degradation curve for the test material shows that the test material has satisfied the 10-Day window validation criterion, whereby 60% degradation must be attained within 10 days of the degradation exceeding 10%.

The test material can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

The substance is not persistent in the acqueous environment and therefore exposure to parent substance is not of significant concern.

Partition Coefficient:

The partition coefficient was determined using the shake-flask method, Method A8 of Commission Directive 92/69/EEC.

The partition coefficient of the test material has been determined to be 1.79 at 21.4 ± 0.5°C, log10 Pow 0.254. Substances having a 1og10Pow of greater than 3 are regarded as having the potential to bioaccumulate in the environment.

Since log Pow < 4.5 the bioaccumulation potential of the subsmission substance is not considered to be of significant concern.

Adsorption Coefficient: No determination of the adsorption coefficient was possible by the HPLC estimation method, Method C19 of Commission Directive 200l/39/EC, as the method is not valid for organic acids. Therefore in place of experimental data, an estimate of the adsorption coefficient was obtained by calculation using Quantitative Structure Activity Relationships (QSAR's), the details of which are provided in the technical guidance documents in support of Commission Directive 93/67/EEC on risk assessment for new substances. Using a QSAR calculation, the adsorption coefficient of the test material was estimated to be log10 Koc 0.472.

Based on the low Koc the substance is less likely to adsorb to organic matter.