4,4a,5,9b-tetrahydroindeno[1,2-d]-1,3-dioxin

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26 Sep - 12 Nov 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Staatliche Gewerbeaufsicht Hildesheim, Germany

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: at test start (0 h) and test end (127 h)
- Sample storage conditions before analysis: Samples were analysed immediately (if possible, less than 30 min until start of analyses, but at least not more than 2.5% of the total study time).

Buffers:

- pH: 4, 7, 9
- Composition of buffer: pH 4 (0.18 g (nominal) of NaOH and 5.7555 g (nominal) of mono potassium citrate were dissolved in 500 mL double distilled water), pH 7 (0.7358 g (nominal) of NaOH and 4.3012 g (nominal) of KH2PO4 were dissolved in 500 mL double distilled water), pH 9 (0.426 g (nominal) NaOH, 1.8638 g (nominal) KCl and 1.5458 g (nominal) H3BO3 were dissolved in 500 mL double distilled water)
- Preparation of buffer solutions: Buffer solutions were prepared by direct weighing of the buffer components. Buffers were purged with nitrogen for 5 min and then the pH was checked to a precision of at least 0.1 at the test temperature. Buffers were sterilized by filtration through 0.2 µm. Analytical grade chemicals were used.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: HPLC vials, 4 mL volume
- Sterilisation method: Filtration through 0.2 µm
- Lighting: opaque water baths to avoid photolytic effects
- Is there any indication of the test material adsorbing to the walls of the test apparatus? no

TEST MEDIUM
- Volume used/treatment: 4 mL
- Kind and purity of water: double distilled water
- Preparation of test medium: The test solution was prepared at test start via test item stock solution in acetonitrile (25 g/L). Sterile buffer solutions were spiked with the stock solution and filled into the test containers
- Identity and concentration of co-solvent: acetonitrile, ≤ 1% (v/v)

OTHER TEST CONDITIONS
- Adjustment of pH: no

Duration:

127 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

48 mg/L

Duration:

127 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

49.4 mg/L

Duration:

127 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

48.4 mg/L

Number of replicates:

Duplicate samples

Positive controls:

no

Negative controls:

no

Preliminary study:

The preliminary study indicated that the substance is not subject to hydrolysis. No further testing was deemed necessary as less than 10% of the applied test item was transformed after 127 h (5 d) at a temperature of 50 °C and each of the three pH values.

Transformation products:

not measured

% Recovery:

99.58

pH:

4

Temp.:

50 °C

Duration:

127 h

% Recovery:

99.8

pH:

7

Temp.:

50 °C

Duration:

127 h

% Recovery:

99.59

pH:

9

Temp.:

50 °C

Duration:

127 h

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

other: extrapolation from 50 °C to 25 °C according to OECD 111

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

other: extrapolation from 50 °C to 25 °C according to OECD 111

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

other: extrapolation from 50 °C to 25 °C according to OECD 111

Details on results:

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

Validity criteria fulfilled:

yes

Conclusions:

The hydrolysis test resulted in hydrolysis < 10% after 5 d at pH 4, 7 and 9 and 50 °C. Thus, a DT50 > 1 yr at pH 4, 7 and 9 and 25 °C was extrapolated in accordance with the guideline (OECD 111, GLP). Thus, the substance is hydrolytically stable.

Executive summary:

One experimental study is available investigating the hydrolytic properties of the test substance (2015). The study was performed according to OECD 111 (GLP). A preliminary test with a concentration of approx. 48 mg/L was performed at 3 different pH values and 50 °C. The result from HPLC-DAD analysis indicated that the test substance is hydrolytically stable. After 5 d, < 10% hydrolysis was observed at pH 4, 7 and 9 and 50 °C. Thus, in accordance with the guideline no main test was considered necessary and the results from the preliminary test were extrapolated to 25 °C. At 25 °C the DT50 of the test substance was estimated to be > 1 yr at pH 4, 7 and 9.

Description of key information

The hydrolysis test resulted in hydrolysis < 10% after 5 d at pH 4, 7 and 9 and 50 °C. Thus, a DT50 > 1 yr at pH 4, 7 and 9 and 25 °C was extrapolated in accordance with the guideline (OECD 111, GLP). Thus, the substance is hydrolytically stable.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

One experimental study is available investigating the hydrolytic properties of the test substance (2015). The study was performed according to OECD 111 (GLP). A preliminary test with a concentration of approx. 48 mg/L was performed at 3 different pH values and 50 °C. The result from HPLC-DAD analysis indicated that the test substance is hydrolytically stable. After 5 d, < 10% hydrolysis was observed at pH 4, 7 and 9 and 50 °C. Thus, in accordance with the guideline no main test was considered necessary and the results from the preliminary test were extrapolated to 25 °C. At 25 °C the DT50 of the test substance was estimated to be > 1 yr at pH 4, 7 and 9.