Humic acids and fulvic acids extracted from leonardite, reaction product with formaldehyde, potassium hydrogen sulfite, sodium hydrogen sulfite and potassium hydroxide

Hydrolysis

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

Test material information

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 test

Duration of test 1

Duration:

5 d

pH:

4.1

Temp.:

50 °C

Initial conc. measured:

ca. 1 g/L

Duration of test 2

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

ca. 1 g/L

Duration of test 3

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.