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Environmental fate & pathways

Hydrolysis

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Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
6th February and 1st March 1995
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study carried out in accordance with method C7 of commission directive 92/69/EEC and in accordance with GLP. The test material was well characterised

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Analytical monitoring:
yes
Details on sampling:
Samples were taken at 0 hours, 2.4 hours and 5days. a aliquot of test solutin was taken and diluted prior to analysis by HPLC
Buffers:
pH 4 buffer:
potassium dihydrogen citrate (4.6 g) was dissolved in distilled water. PH adjusted to 4 with 1M sodium hydroxide solution as the temperature of the solution reached 50 oC +/- 0.5 oC

pH 7.00 buffer
potassium dihydrogen orthophosphate (2.77 g0 was dissolved in distilled water (1 litre). pH was adjusted to 4.0 with 1M sodium hydroxide solution.

pH 9 buffer
Potassium chloride (1.5g) and boric acid (1.25 g) were dissolved in distilled water (1 litre). the pH was adjusted to 9.00 with 1 M sodium hydroxide solution
Details on test conditions:
performed at 50 C and pH 4, 7.00 and 9

nine 100 ml volumetric flasks were pre-calibrated at 50 oC with distilled water (100 ml at 20 oC) in a water bath at 50 oC. the flasks were then marked at the new level.

Prior to the test, these flasks were rinsed with ethanol and alowed to drip dry. The buffer solutions were autoclaved at 121 oC for 15 minutes and then purged with nitrogen for 15 minuts prior to use.
Duration of testopen allclose all
Duration:
5 d
pH:
4
Temp.:
50 °C
Initial conc. measured:
ca. 0.25 µg/L
Duration:
5 d
pH:
7
Temp.:
50 °C
Initial conc. measured:
ca. 0.25 µg/L
Duration:
5 d
pH:
9
Temp.:
50 °C
Initial conc. measured:
ca. 0.25 µg/L
Number of replicates:
three
Positive controls:
yes
Remarks:
spiking solution - test substance was weighedinto a 20 ml volumetric flask and made to volume with methanol to give a final concentration of 52854 ug/ml
Negative controls:
yes
Remarks:
buffer solution

Results and discussion

Preliminary study:
at 50 C showed less than 10% was hydrolysed after 2.4 hrs and 5 days at all pH measurements
Test performance:
No signifance difference between initial and those made at 2.4 hrs. Negative value observed are within the measurement error.
Transformation products:
not specified
Total recovery of test substance (in %)
% Recovery:
ca. 101.3
pH:
4
Temp.:
50 °C
Dissipation DT50 of parent compoundopen allclose all
pH:
7
Temp.:
25 °C
DT50:
ca. 1 d
pH:
9
Temp.:
25 °C
DT50:
ca. 1 yr
Details on results:
50 % hydrolysis occuring in 2.4 hours at 50 oC is equivalent to a half-life of 1 day at 25 oC

10% hydrolysis occurring in 5 days at 50 oC is equivalent to a half life of 1 year at 25 oC

applying these criteria to the results obtaind the half life at 25 oC can be estimated to be beween one day and one year at pH 4 and 7, and greater thanor equal to one year at pH 9.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
A-88820.605 has been found to undergo significant hydrolysis at 50 oC for pH 4 and 7 and 10 % hydrolysis at pH 9.