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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:
09 April 2014 to 03 September 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)
Specific details on test material used for the study:
Test material: FAT 36034/W
Batch no.: Q30450ADZX
Appearance/color: Solid/red
Radiolabelling:
no
Details on sampling:
The test item solutions were prepared by adding 1 mL stock solution into an 100 mL volumetric flask and accurately filled up with the buffer solutions. Under argon atmosphere 2.0 mL of the test item solutions were given into several amber glass vials. The vials were closed with Teflon
sealed screw caps. At the sampling time the samples were diluted with 2.0 mL acetonitrile. The concentration did not exceed 0.01 M or the half saturation concentration. The determined effective concentrations prior to storage at 50 °C were 1.24 mg/L at pH 4, 1.29 mg/L at pH 7 and
1.34 mg/L at pH 9.
Buffers:
The test was carried out at three different pH values: 4.0, 7.0 and 9.0. For this purpose, buffer solutions were prepared using reagent grade chemicals and deionized water. Applicable buffer systems are described in the Appendix of EC method C.7 (92/69/EC), OECD guideline 111. The citrate buffer pH 4, the phosphate buffer pH 7 and the borate buffer pH 9 were prepared in a concentration of 0.05 M on the basis of the undissociated acids. The pH value of the buffer solutions used during the test were determined with a calibrated pH meter at the selected temperature with a precision of 0.1 pH units.
Details on test conditions:
The test was carried out using a thermostatically controlled water bath at +/- 0.5 °C of the chosen temperature. The temperature was kept and measured to within +/- 0.1 °C. Photolytic interference was avoided. All suitable precautions were taken to exclude dissolved oxygen (bubbling the buffer with argon for five minutes before preparing the test solution).
Duration:
120 h
pH:
4
Temp.:
50 °C
Initial conc. measured:
1.24 mg/L
Duration:
120 h
pH:
7
Temp.:
50 °C
Initial conc. measured:
1.29 mg/L
Duration:
120 h
pH:
9
Temp.:
50 °C
Initial conc. measured:
1.34 mg/L
Number of replicates:
4 at each pH-value
Preliminary study:
A preliminary test was performed at 50 +/- 0.5 °C at three pH values: 4.0, 7.0 and 9.0. A sufficient number of measurements were made, in order to
be able to estimate whether for each pH value and at 50 °C, the half-life time (t1/2) is less than 10 % of hydrolysis after 120 hours. These values
correspond to a half-life time higher than one year under conditions more representative of those of the environment (25 °C).
Transformation products:
not measured
% Recovery:
107
pH:
4
Temp.:
50 °C
Duration:
120 h
% Recovery:
99.2
pH:
7
Temp.:
50 °C
Duration:
120 h
% Recovery:
99.3
pH:
9
Temp.:
50 °C
Duration:
120 h
pH:
4
Temp.:
25 °C
DT50:
> 1 yr
Type:
(pseudo-)first order (= half-life)
Remarks on result:
hydrolytically stable based on preliminary test
pH:
7
Temp.:
25 °C
DT50:
> 1 yr
Type:
(pseudo-)first order (= half-life)
Remarks on result:
hydrolytically stable based on preliminary test
pH:
9
Temp.:
25 °C
DT50:
> 1 yr
Type:
(pseudo-)first order (= half-life)
Remarks on result:
hydrolytically stable based on preliminary test
Details on results:
No significant changes of the content in the samples were observed. At pH 4, 7 and 9 less than 10 % of the test item were hydrolysed within 120 hours at 50 °C.

Table1:        Time course of FAT 36034/W concentration at pH 4 at 50 °C


























Time



Determined Content


of FAT 36034/W in Sample



Actual concentration



[h]



[mg/L]



in % of initial conc.



0



1.24



100



120



1.32



107



 


Table2:        Time course of FAT 36034/W TE concentration at pH 7 at 50 °C


























Time



Determined Content


of FAT 36034/W in Sample



Actual concentration



[h]



[mg/L]



in % of initial conc.



0



1.29



100



120



1.28



99.2



 


Table3:        Time course of FAT 36034/W TE concentration at pH 9 at 50 °C


























Time



Determined Content


of FAT 36034/W in Sample



Actual concentration



[h]



[mg/L]



in % of initial conc.



0



1.34



100



120



1.33



99.3


Validity criteria fulfilled:
yes
Conclusions:
FAT 36034/W was found to be hydrolytically stable.
Executive summary:

The abiotic degradation of the test substance as a function of pH in aqueous solution was determined according to OECD guideline 111 and EC method C.7 (440/2008). A preliminary test was performed at 50 +/- 0.5 °C at three pH values: 4.0, 7.0 and 9.0. The degradation of FAT 36034/W was less than 10 % at pH 4, pH 7, pH 9 at 50 °C over a period of 120 hours. Therefore, the corresponding half-life time at 25 °C can be estimated to be longer than one year.

Description of key information

The abiotic degradation of the test substance as a function of pH in aqueous solution was determined according to OECD guideline 111 and EC method C.7 (440/2008). The degradation of FAT 36034/W was less than 10 % at pH 4, pH 7, pH 9 at 50 °C over a period of 120 hours. Therefore, the corresponding half-life time at 25 °C can be estimated to be longer than one year.

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
25 °C

Additional information