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Administrative data

Endpoint:
hydrolysis
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
from January 23, 2007 to March 5. 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study was carried out in accordance with internationally valid GLP principles.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guideline
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)

Test material

Constituent 1
Reference substance name:
Humic acids, potassium salts
EC Number:
271-030-1
EC Name:
Humic acids, potassium salts
Cas Number:
68514-28-3
IUPAC Name:
68514-28-3
Details on test material:
- Name of test material (as cited in study report): Humic acids, potassium salts
- Molecular formula: not known - UVCB substance
- Molecular weight: not known - UVCB substance
- Substance type: technical product
- Physical state: solid
- Lot/batch No.: 16. 5. 2007/R
- Expiration date of the lot/batch: 05/2022
- Stability under test conditions: stable
- Storage condition of test material: dry conditions

Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent/transformation products: 0, cca 1 day, cca 2 days, cca 4 days, cca 5 days
- Sampling method: sampling from volumetric flask by pipette and diluting with water to required concentration.
- Sampling intervals/times for pH measurements:
- Sampling intervals/times for sterility check:
- Sample storage conditions before analysis: The samples were analyzed in a short time after sampling.
- Other observation: no
- Temperature control: The actual temperature of the thermostatic bath was controlled during the whole test every when the sampling was done.
Buffers:
- pH: 4,7,9
- Type and final molarity of buffer: Buffer mixtures – Clark and Lubs
- Composition of buffer:
pH 4: phthalate buffer
pH 7: fosphate buffer
pH 9: borate buffer
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: volumetric flask 250 mL
- Sterilisation method: no
- Lighting: no (aluminium foil)
- Is there any indication of the test material adsorbing to the walls of the test apparatus? no

TEST MEDIUM
- Volume used/treatment 250 mL
- Kind and purity of water: distilled water
- Preparation of test medium:
- Renewal of test solution:

OTHER TEST CONDITIONS
- Adjustment of pH: The actual pH value of each buffer was measured. The pH-meter calibrated to buffer solutions CertiPUR was used.
- Adjustment of temperature: The actual temperature of the thermostatic bath was controlled during the whole test every when the sampling was done. The calibrated thermometer was used and a temperature correction was taken into account via information from the calibration list.
Duration of testopen allclose all
Duration:
5 d
pH:
4.1
Temp.:
50 °C
Initial conc. measured:
ca. 1 g/L
Duration:
5 d
pH:
7
Temp.:
50 °C
Initial conc. measured:
ca. 1 g/L
Duration:
5 d
pH:
8.8
Temp.:
50 °C
Initial conc. measured:
ca. 1 g/L
Number of replicates:
2
Positive controls:
no
Negative controls:
no

Results and discussion

Preliminary study:
The preliminary test shows that less than 10 % of the test substance was hydrolysed within 5 days period at the pH 4.1, 7.0 and 8.8.
The half-life time of hydrolysis can therefore be expected grater than one year at 25°C and further testing was not required.
Transformation products:
no
Details on results:
TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: yes
- Anomalies or problems encountered (if yes): no

Any other information on results incl. tables

Hydrolysis at pH 4

Results of preliminary test : pH = 4.1

Sampling

Measurement

Difference to time = 0

(%)

Time

(days)

Temperature

(°C)

No.

Absorbance

(AU)

0

50.0

I

A

1.3433

B

1.3441

II

A

1.3506

B

1.3490

Average

1.347

0.0

1.12

50.0

I

A

1.3085

B

1.3095

II

A

1.3129

B

1.3138

Average

1.311

-2.6

3.92

50.0

I

A

1.3507

B

1.3510

II

A

1.3385

B

1.3350

Average

1.344

-0.2

4.84

50.0

I

A

1.3320

B

1.3332

II

A

1.3301

B

1.3310

Average

1.332

-1.1

Hydrolysis at pH 7

Results of preliminary test : pH = 7.0

Sampling

Measurement

Difference to time = 0

(%)

Time

(days)

Temperature

(°C)

No.

Absorbance

(AU)

0

50.0

I

A

2.3225

B

2.3214

II

A

2.3238

B

2.3235

Average

2.323

0.0

1.06

50.0

I

A

2.3088

B

2.3203

II

A

2.3039

B

2.3011

Average

2.309

-0.6

3.90

50.0

I

A

2.2852

B

2.2885

II

A

2.2871

B

2.2877

Average

2.287

-1.5

4.82

50.0

I

A

2.3255

B

2.3244

II

A

2.3312

B

2.3309

Average

2.328

0.2

Hydrolysis at pH 9

Results of preliminary test : pH = 8.8

Sampling

Measurement

Difference to time = 0

(%)

Time

(days)

Temperature

(°C)

No.

Absorbance

(AU)

0

50.0

I

A

2.3383

B

2.3371

II

A

2.3361

B

2.3373

Average

2.337

0.0

1.07

50.0

I

A

2.3629

B

2.3603

II

A

2.3619

B

2.3614

Average

2.362

1.0

3.89

50.0

I

A

2.3310

B

2.3261

II

A

2.3291

B

2.3294

Average

2.329

-0.4

4.80

50.0

I

A

2.3413

B

2.3399

II

A

2.3361

B

-

Average

2.339

0.1

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Executive summary:

The half-life times of hydrolysis at all tested pH (4, 7 and 9) and at 25°C were estimated as higher than 1 year.

The estimation is performed with respect to the results of preliminary test and with respect to the conclusion stated in the used methodology - Method C.7 – Degradation – Abiotic Degradation Hydrolysis as a Function of pH, Directive 92/69/EEC. Published in OJ No L 383A December 1992.