Sodium bis[N-(2-chlorophenyl)-2-[[2-hydroxy-5-(N-methylsulphamoyl)phenyl]azo]-3-oxobutyramidato(2-)]cobaltate(1-)

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: screening test, other

Remarks:

Biodegradation in water: modified MITI test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 May 1996 - 29 October 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))

Deviations:

yes

Remarks:

The test substance will be running in duplicate instead of in triplicate

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: 9
- Expiration date of the lot/batch: 06/2000

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Solubility of the test substance in the solvent/dispersant/vehicle/test medium: 20 g/l [in water]

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, industrial (adaptation not specified)

Remarks:

Mixture of polyvalent bacteria collected on June 03, 1996 in the aeration tank of a domestic sewage treatment plant, PRO RHENO Basel communal.

Details on inoculum:

- Concentration of sludge:100 mg/l suspended solids

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium:
3 ml of each following stock solutions were added per 1 litre distilled water to form the test medium:
Stock solution A:
8,50 g of potassium acid phosphate, 21,75 g of di-potassium hydrogen phosphate, 22,18 g of di-sodium hydrogenphosphate dihydrate and 1,70 g of ammonium chloride were dissolved in distilled water and adjusted to 1 litre. The pH value of this solution was 7,2.

Stock solution B:
22,50 g of magnesium sulfate heptahydrate were dissolved in distilled water and adjusted to 1 litre.

Stock solution C:
36,40 g of calcium chloride dihydrate were dissolved in distilled water and adjusted to 1 litre.

Stock solution D:
0,25 g of ferric chloride hexahydrate were dissolved in distilled water and adjusted to 1 litre.

- Test temperature: 25 °C ± 2 °C

Reference substance:

other: Sodium benzoate powder, for foodstuffs (restricted use) [Merck No. 6290]

Key result

Parameter:

% degradation (DOC removal)

Value:

9

Sampling time:

28 d

Remarks on result:

other: St. dev. has not specified

Parameter:

other: ThOD

Value:

9

Sampling time:

28 d

Remarks on result:

other: St. dev. has not specified

Details on results:

None

Parameter:

BOD5

Value:

0 mg O2/g test mat.

Results with reference substance:

The biodegradation of the reference substance corrected by the inoculum control and measured as BOD versus ThOD was 78 % after 7 days, 80 % after 14 days, 81 % after 28 days.

Negative values or values above 100 will be given as 0 % or 100 % respectively. The results expressed in % are given as full number.

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

There was 9 % biodegradation was found with FAT 20035/D but it was considered as non-biodegradable after 28 days of incubation.

Executive summary:

The inherent biodegradability of FAT 20035/D was determined in a 28 days MITI (II) - Test according to the OECD Guideline for Testing of Chemicals No. 302C, adopted Paris 1981. This study was performed in compliance with Good Laboratory Practice (GLP) in Switzerland, Procedures and Principles, March 1986, issued by the Federal Department of the Interior and the Intercantonal Office for the Control of Medicaments, Switzerland. The test substance was tested in a concentration of 30 mg/l. The reference substance (Sodium benzoate) was tested in a concentration of 100 mg/l. Biodegradation after 28 days of the test substance FAT 20035/D was 9 % while of the reference substance was 81 %. The BOD5 after 5 days was 0 mg O2/g. Based on the present study there was 9 % biodegradation was found with FAT 20035/D but it was considered as non-biodegradable after 28 days of incubation.

Description of key information

Test substance is considered as non-biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

In a key study, the inherent biodegradability of FAT 20035/D was determined in a 28 days MITI (II) - Test according to the OECD Guideline for Testing of Chemicals No. 302C, adopted Paris 1981. This study was performed in compliance with Good Laboratory Practice (GLP) in Switzerland, Procedures and Principles, March 1986, issued by the Federal Department of the Interior and the Intercantonal Office for the Control of Medicaments, Switzerland. The test substance was tested in a concentration of 30 mg/l. The reference substance (Sodium benzoate) was tested in a concentration of 100 mg/l. Biodegradation after 28 days of the test substance FAT 20035/D was 9 % while of the reference substance was 81 %. The BOD5 after 5 days was 0 mg O2/g. Based on the present study there was 9 % biodegradation was found with FAT 20035/D but it was considered as no-biodegradable after 28 days of incubation. Several other supporting studies which were carried out according to GLP guideline showed the following results:

BOD5 of FAT 20035/C and FAT 20035/A is 0 mg/g O2

COD of FAT 20035/D is 1100 mg/g O2

COD of FAT 20035/C is 672 mg/g O2

COD FAT 20035/A is 1302 mg O2/g

Relevant is the BOD5/COD quotient is '0 'which is not > 0.5 , therefore the substance is not indicative of rapid degradation. Considering the data from key study and supporting studies, the test substance FAT 20035 is regarded to be not biodegradable.