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Environmental fate & pathways

Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 Aug 2005 - 19 Sep 2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
other: Directive 92/69/EEC Method C.7 OECD Guidelines No. 111
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 52834
- Expiration date of the lot/batch: 8 Nov 2004
- Purity: 99.08%
- Storage condition: Room temperature in the dark
Radiolabelling:
not specified
Analytical monitoring:
yes
Details on sampling:
An aliquot was diluted to volume with acetone for analysis by gas chromatography (GC). Buffer salts which had precipated from solution on dilution with acetone were removed by filtration prior to analysis.
Buffers:
- pH: 4.0
Potassium dihydrogen orthophosphate (6.06g) and disodium hydrogen orthophosphate dodecahydrate (10.1g) were dissolved in purified water (1900ml), and the pH was adjusted to 4.0 +/- 0.5 with orthophosphoric acid. The volume was then adjusted to 2000mL with purified water.

- pH: 7.0
Potassium dihydrogen orthophosphate (13.6g) was dissolved in purified water (1900mL), 1M sodium hydroxide (60mL) was added and the pH was adjusted to 7.0 +/- 0.5 with 1.0M hydrochloric acid. The volume was then adjusted to 2000mL with purified water

- pH: 9.0
Disodium tetraborate decahydrate (33.2g) and potassium dihydrogen orthophosphate (3.58g) were dissolved in purified water (1900mL), and the pH was adjusted to 9.0 +/- 0.5 with 1.0M hydrochloric acid. The volume was then adjusted to 2000mL with purified water.

- Linearity range: 0 - 100mg/L, with regression coefficient of 0.992
Details on test conditions:
TEST SYSTEM
Aliquots of 1mL of stock solution of test item in purified water (100g/L were added to separate 100mL Wheaton vials containing buffer solution (100mL).
At each sampling time, an aliquot (1mL) was diluted to volume (20ml) with acetone for analysis by GC.
Buffer salts which had precipitated from solution on dilution with acetone were removed by filtration (0.2 µm, PTFE) prior to analysis.
Duration:
120 h
pH:
4
Temp.:
50 °C
Initial conc. measured:
1 060 mg/L
Remarks:
Preliminary investigation results
Duration:
120 h
pH:
7
Temp.:
50 °C
Initial conc. measured:
101 mg/L
Remarks:
Preliminary investigation results
Duration:
120 h
pH:
9
Temp.:
50 °C
Initial conc. measured:
1 060 mg/L
Remarks:
Preliminary investigation results
Number of replicates:
2
Preliminary study:
Results from the preliminary investigation showed that there was no significant change in the concentration of the test item when incubated in pH 4, 7 and 9 buffer solutions at 50 ± 0.5°C. Less than 10% hydrolysis had occured after 120 hours (5 days) under these conditions, equivalent to a half-life of greater than 1 year under environmental conditions (25°C).
Transformation products:
not specified
Key result
pH:
4
Temp.:
50 °C
DT50:
> 1 yr
Key result
pH:
7
Temp.:
50 °C
DT50:
> 1 yr
Key result
pH:
9
Temp.:
50 °C
DT50:
> 1 yr
Validity criteria fulfilled:
not specified
Conclusions:
The preliminary study showed that at pH 4, 7 and 9 and 50 ± 0.5°C, less than 10% hydrolysis had occurred after 120 hours (5 days), equivalent to a half-life of greater than 1 year under environmental conditions (25°C)

The test item was determined to be hydrolytically stable under acidic, neutral and basic conditions.

Description of key information

At pH 4, 7 and 9 and 50 ± 0.5°C, less than 10% hydrolysis had occurred after 120 hours (5 days), equivalent to a half-life of greater than 1 year under environmental conditions (25°C)

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
50 °C

Additional information