Reaction mass of Cobaltate(1-), bis[6-(amino-κN)-5-[2-[2-(hydroxy-κO)-4-nitrophenyl]diazenyl-κN1]-N-methyl-2-naphthalenesulfonamidato(2-)]-, sodium (1:1) and disodium [6-amino-5-[(2-hydroxy-4-nitrophenyl)azo]-N-methylnaphthalene-2-sulphonamidato(2-)][6-amino-5-[(2-hydroxy-4-nitrophenyl)azo]naphthalene-2-sulphonato(3-)]cobaltate(2-)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

Preparation of the inoculum: Higher sludge weight after the washing procedure (Sludge concentrations in the test according to the guidelines) and 4 instead of 5 test concentrations.

GLP compliance:

yes

Specific details on test material used for the study:

Code number: FAT 20036/F
Batch-No: 1
Purity: ca. 97.7%
Appearance: Solid
Solubility: 80 mg/L (in water)
Storage: room temperature
Expiration date: 07/99

Analytical monitoring:

no

Details on sampling:

Not available

Vehicle:

no

Details on test solutions:

Not available

Test organisms (species):

activated sludge

Details on inoculum:

- Organism: Activated sludge from a communal sewage treatment plant (ARA -Pro Rheno Basel)
- Sludge pretreatment: 3 times washing with tap water and addition of synthetic sewage (a day before the main test).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Remarks on exposure duration:

None

Post exposure observation period:

Not available

Hardness:

Not available

Test temperature:

20.8 °C

pH:

7.3 before the test beginning

Dissolved oxygen:

measured

Salinity:

Not applicable

Nominal and measured concentrations:

- Stock solutions: 500 mg/l test substance / reference substance in deionized water.
- Test concentrations : 320, 100, 32 and 10 mg/l of the test substance and 32, 10 and 3.2 mg/l of the reference substance

Details on test conditions:

- Temperature : 20.8 °C
- Sludge dry weight: 1.50 g/l
- Test volume : 100 ml
- Test duration: 3 h
- Estimation technique : O2 - consumption, measured with an oxygen sensitive electrode, system : OXI DIGI 530 (SAV : 00 109)
- Aeration : 0.1 - 0.2 l/min by pasteur-pipette.
- pH of sludge : 7.3 before the test beginning

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol (Merck 821768)

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

Not available

Results with reference substance (positive control):

The IC50 (3 h) of the reference substance (3,5-Dichlorophenol) was found to be 9.0 mg/l

Reported statistics and error estimates:

Not available

ACTIVATED - SLUDGE - INHIBITION / IC50 (3 h)

OXYGEN - CONSUMPTION - TEST

Control	pH after 3 hrs	1) O2 -consumption (in cm)	2) Time (in cm)	mg O2/min/L	C=control1) 2 cm = 0.8 mg/l O22) 2 cm = 1 min
C1	8.0	3.7	4.0	0.74	C1/C2: 0.00% C2/C1: 0.00%
C2	7.8	3.5	3.8	0.74	Mean C: 0.74

Test substance mg/L	pH after 3 hour	1) O2 -consumption (in cm)	2) Time (in cm)	mg O2 pro min/L	% of control	% inhibition
320	7.6	4.0	4.7	0.68	91.89	8.11
100	7.8	3.8	4.4	0.69	93.24	6.76
32	7.9	4.0	4.4	0.73	98.65	1.35
10	7.9	3.8	4.4	0.69	93.24	6.76

3,5 -Dichlrophenoö (mg/L)	pH after 3 hour	1) O2 -consumption (in cm)	2) Time (in cm)	mg O2 pro min/L	% of control	% inhibition
32	8.0	0.7	4.7	0.12	16.22	83.78
10	7.9	1.9	4.3	0.35	47.30	52.70
3.2	7.9	3.0	4.2	0.57	77.03	22.97

Test substance IC50 (3 h) = > 320.0 mg/l

3,5-Dichlorophenol IC50 ( 3 h) = 9.0 mg/l

Validity criteria fulfilled:

yes

Conclusions:

The IC50 (3 h) of the test substance FAT 20036/F was found to be greater than 320 mg/l

Executive summary:

The toxicity of FAT 20036/F to activated sludge was determined in a 3-hours respiration inhibition test according to the EEC Method No. L 133/118 -122 and to the OECD Guideline No. 209. The test was performed in compliance with the Good Laboratory Practice (GLP) Regulations of Switzerland.

The test substance concentrations tested were 320, 100, 32 and 10 mg/l. The reference substance, 3,5-Dichlorophenol was tested in concentrations of 32, 10 and 3.2 mg/l.

The IC50 (3 h) of the test substance FAT 20036/F was found to be greater than 320.0 mg/l

IC50 (3 h) of the reference substance 3,5-Dichlorophenol was found to be 9.0 mg/l

Description of key information

A key study was performed to determine the toxicity of FAT 20036/F to activated sludge was determined in a 3-hours respiration inhibition test according to the EEC Method No. L 133/118 -122 and to the OECD Guideline No. 209. The test was performed in compliance with the Good Laboratory Practice (GLP) Regulations of Switzerland.

The IC50 (3 h) of the test substance FAT 20036/F was found to be greater than 320.0 mg/l

IC50 (3 h) of the reference substance 3,5-Dichlorophenol was found to be 9.0 mg/l.

Several studies, (supporting studies), were also performed on the different batches to test the toxicity on micro-organisms.

BST, (toxicity to micro-organisms), was found to be greater than 300 mg/L on batch A, B, C and D.

For the batch F, IC50 was found to be greater than 320 mg/L.

 

Key value for chemical safety assessment

EC50 for microorganisms:

320 mg/L