Humic acids, potassium salts

Sediment toxicity

Administrative data

Endpoint:

sediment toxicity: long-term

Data waiving:

other justification

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with Column 2 Annex X REACH, the long-term toxicity testing does not need to be carried out as the results of the chemical safety assessment indicates the need to investigate further the effects of the substance and/or relevant degradation products on sediment organisms. According to results of hydrolysis study, the half time of degradation is estimated to be more than 1 year. Therefore, no degradation product of parental substance are expected in sediment. This resume is supported by triggering criteria in Guidance on information requirements and chemical safety assessment, Chapter R.7b, part R.7.8.10.3 c), point iii. Information on degradation of the parent compound in the water column showing formation of relevant metabolites (see Section R.7.1) that will be distributed to the sediment and point iv. Information on degradation of the parent compound in the sediment showing formation of metabolites exclusively in this compartment (i.e. indications of anaerobic/aerobic degradation in the sediment to relevant metabolites). Neither one of points is fulfiled for the substance.

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

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:

guideline study

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)

Radiolabelling:

no

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:

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

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

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

hydrolytically stable based on preliminary test

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

Validity criteria fulfilled:

yes

Conclusions:

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.

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.