Sodium 2-[[4-[3-(4,5-dichloro-2-methylphenyl)-4,5-dihydro-1H-pyrazol-1-yl]phenyl]sulphonyl]ethanesulphonate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

From August 15 to September 12, 2002

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Justification for type of information:

The read across approach is detailed into the document attached to the IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

adopted 17 July 1992

Principles of method if other than guideline:

The study described was conducted in accordance with ISO/IEC 17025.

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of activated sludge: ARA Werdhölzli, CH-8048 Zürich, 13 August 2002; 9.30 a.m.
- Adoptation: activated sludge was used immediately after sampling from the treatment plant without adaptation.
- Pre-treatment: prior to the test the sludge was washed twice with tap water.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: aerobic mineral salts medium prepared with deionised water (conductivity: <1.5 µS/cm; DOC: <0.3 mg/l).
- Vessels: 1200 ml closed glass bottle (tightly closed with a butyl rubber stopper) containing a total volume of test solution of 400 ml.
- Additional substrate: none, testr item and functional control as sole organic carbon sources.
- Test temperature: 22 ± 0.5 °C
- Suspended solids concentration: 30 mg/l of suspended solids.
- Continuous darkness: yes, dark room.
- Stirring: the test vessels were agitated on an orbital shaker (100 r.p.m.).

TEST SYSTEM
- Number of test vessels: containing inoculum, test medium and test substance, two replicates.

CONTROL AND BLANK SYSTEM
- Inoculum blank: containing inoculum and test medium, two replicates.
- Reference control: containing inoculum, test medium and sodium benzoate as ready biodegradable reference compound, one replicate.
- Abiotic sterile control: not determined.
- Toxicity control: not determined.

Reference substance:

benzoic acid, sodium salt

Remarks:

107.8 mg/l

Parameter:

% degradation (O2 consumption)

Value:

-0.3

Sampling time:

28 d

Details on results:

Based on the data of the individual O2 determinations, no biodegradability in the Manometric Respirometry Test of trest item was observed within 28 days of incubation.
Due to the limited water solubility of the test material, biodegradation based on DOC measurements could not be assessed.

The COD value of the test substance was determined as 1.440 mg O2/mg substance.

At the end of the test the pH value of both inoculum blanks and the procedure control was 7.1 and 6.6, respectively. The pH value of both test suspensions was 7.1, respectively.
At the applied initial test concentration of 100 mg/l the test material was not completely dissolved.

Results with reference substance:

The procedure control sodium benzoate reached 95 % biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.
The ThOD of the reference compound sodium benzoate was calculated to be 1.665 mg O2/mg substance.

Time (days)	Inoculum blank*	Test unit no. 1 containing test material			Test unit no. 1 containing test material			Mean Degradation of no. 1+2 (%)
	Total O2 uptake in test sample (mg)	Total O2 uptake in test sample (mg)	BOD (mg O2/mg substance)	Degradation (%)**	Total O2 uptake in test sample (mg)	BOD (mg O2/mg substance)	Degradation (%)**
0	0.0	0.0	0.00	0.0	0.0	0.00	0.0	0.0
1	1.5	0.4	-0.03	-1.9	0.9	-0.01	-0.9	-1.4
4	4.3	3.5	-0.02	-1.4	4.0	-0.01	-0.7	-1.0
7	3.5	2.8	-0.02	-1.1	3.6	0.00	0.3	-0.4
11	5.2	5.0	-0.01	-0.4	6.1	0.02	1.6	0.6
14	7.7	7.6	0.00	-0.1	6.2	-0.04	-2.6	1.4
18	8.0	6.6	-0.04	-2.4	7.7	-0.01	-0.5	-1.5
21	8.2	7.7	-0.01	-0.8	8.7	0.01	0.9	0.1
24	9.1	7.6	-0.04	-2.6	8.0	-0.03	1.9	-2.2
28	10.7	10.5	0.00	-0.3	10.5	0.00	-0.3	-0.3

* Mean of two replicates

** The calculation is based on the nominal concentration of the test substance of 100 mg/l and a COD value in mg O₂/mg test substance of 1.440

Interpretation of results:

not readily biodegradable

Conclusions:

The substance resulted to be not biodegradable in the Manometric Respirometry Test within 28 days of incubation.

Executive summary:

The biodegradability of test item exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions. The study was conducted in accordance with the OECD guideline 301F.

No biodegradability of test item, based on O2 consumption, was observed within 28 days as compared to the chemicaloxygen demand (COD). The procedure control sodium benzoate reached 95 % biodegradation after 14 days, thus confirming suitability of inoculum and test conditions.

Due to the limited water solubility of the test material, biodegradation based on DOC measurements could not be assessed.

Conclusion

The substance resulted to be not biodegradable in the Manometric Respirometry Test within 28 days of incubation.

Description of key information

The substance resulted to be not biodegradable in the Manometric Respirometry Test within 28 days of incubation.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

There are no specific information about the readily biodegradability potential of Fluorescent Brightener 313, thus the available information on the structural analogous Similar Substance 01 have been taken into consideration; the read across approach can be considered as appropriate and suitable to assess the property under investigation (details about the approach are reported into the IUCLID section 13).

The biodegradability of the Similar Substance 01 exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions. The study was conducted in accordance with the OECD guideline 301F. No biodegradability of test item, based on O2 consumption, was observed within 28 days as compared to the chemicaloxygen demand (COD). The procedure control sodium benzoate reached 95 % biodegradation after 14 days, thus confirming suitability of inoculum and test conditions. Due to the limited water solubility of the test material, biodegradation based on DOC measurements could not be assessed.