Disodium [N-(2-chlorophenyl)-2-[(2-hydroxy-5-nitrophenyl)azo]-3-oxobutyramidato(2-)][3-hydroxy-4-[(2-hydroxy-1-naphthyl)azo]-7-nitronaphthalene-1-sulphonato(3-)]chromate(2-)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

August 18, 1977

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

This method was designed to evaluate the acute bacteriotoxicity to sewage sludge or isolated suspended bacteria under aerobe conditions.
The active sewage sludge was directly used from the Husmann apparatus on day 3 to 5.
The tested concentrations ranged from 1 to 300 mg/l.
Test tubes were inoculated with one drop of the bacteria sewage sludge suspension and incubated for 12-24 hours at 25 ± 2°C in an incubator.
Basing on visible opacity of the test solution and in reference to the control growth, was determined the lowest concentration at which no bacterial growth was observed.

GLP compliance:

no

Analytical monitoring:

not specified

Details on sampling:

- Concentrations: 1, 5, 10, 20, 50, 100, 200 and 300 mg/l

Vehicle:

not specified

Test organisms (species):

activated sludge

Details on inoculum:

- Laboratory culture: directly used from the Husmann apparatus on day 3 to 5

Test type:

not specified

Water media type:

not specified

Limit test:

no

Total exposure duration:

24 h

Details on test conditions:

TEST SYSTEM
- Material: test tubes

TEST MEDIUM / WATER PARAMETERS
-Test Medium: Nutrient Broth

TEST CONCENTRATIONS
- Test concentrations: 1, 5, 10, 20, 50, 100, 200 and 300 mg/l

Reference substance (positive control):

not specified

Duration:

24 h

Dose descriptor:

other: BST

Effect conc.:

> 300 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: BST is the lowest concentration which clearly inhibits bacterial growth, based on visible opacity of the test solution.

Validity criteria fulfilled:

not applicable

Conclusions:

BST > 300 mg/l.

Executive summary:

Method

This method was designed to evaluate the acute bacteriotoxicity to sewage sludge or isolated suspended bacteria under aerobe conditions. The procedure followed an internal method called B-10.

The tested concentrations ranged from 1 to 300 mg/l. Test tubes were inoculated with one drop of the bacteria sewage sludge suspension and incubated for 12-24 hours at 25 ± 2°C in an incubator.

Basing on visible opacity of the test solution and in reference to the control growth, was determined the lowest concentration at which no bacterial growth was observed.

Results

After the incubation period, the substance did not inhibit the bacteria growth. Therefore the bacterial growth inhibition is higher than 300 mg/l that is the highest concentration of substance tested.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

21 May 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

Internal method B-21 followed.
The test method is based on the evaluation of oxygen consumption by bacteria after 3h exposure to test substance in reference to a test control without substance.

GLP compliance:

no

Analytical monitoring:

not specified

Details on sampling:

- Concentrations: 10, 32, 100 mg/l

Vehicle:

not specified

Test organisms (species):

activated sludge

Details on inoculum:

- Laboratory culture: directly used from the Husmann apparatus on day 3 to 5

Test type:

not specified

Water media type:

not specified

Limit test:

no

Total exposure duration:

3 h

Details on test conditions:

TEST CONCENTRATIONS
- Test concentrations: 10, 32 and 100 mg/l

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorphenol

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Results with reference substance (positive control):

- Oxygen consumption after 3h exposure referred to the control:
TEST SUBSTANCE
0.70% at 100 mg/l
0.76% at 32 mg/l
0.78% at 10 mg/l
REFERENCE SUBSTANCE
0.05% at 100 mg/l
0.15% at 32 mg/l
0.80% at 10 mg/l
CONTROL
0.865% no test substance present

- inhibition percentage after 3h exposure referred to the control:
TEST SUBSTANCE
19.1% at 100 mg/l
12.2% at 32 mg/l
9.9% at 10 mg/l
REFERENCE SUBSTANCE
94.3% at 100 mg/l
82.7% at 32 mg/l
7.6% at 10 mg/l

Validity criteria fulfilled:

not applicable

Conclusions:

IC50 > 100 mg/l.

Executive summary:

Method

The study was performed according to internal method B-21.

The test method is based on the evaluation of oxygen consumption by bacteria after 3h exposure to test substance, in reference to a test control without substance.

The oxygen consumed by bacteria was used as expression of viability of the microrganisms; the reference to a control not exposed to substance allowed to calculate the percentage of inhibition and consequently the IC50. 3,5 -Dichlorphenol was used as reference substance.

Results

After 3h exposure the test substance IC50 was higher than 100 mg/l; instead the reference substance IC50 was 19 mg/l.

Description of key information

EC50 > 300 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

300 mg/L

Additional information

The inhibitory effect of the substance under registration on aerobic waste-water bacteria was investigated in three test; two of them were according to internal method called B-10; the third study was performed according to internal method B-21 according to the principles of the actual OECD Guideline for Testing of Chemicals No. 209.

In the two studies conducted following internal method B-10 (Huntsman, 1977; Huntsman, 1984) the substance was tested on activated sludge at concentrations of 1, 5, 10, 20, 50, 100, 200 and 300 mg/l. The EC50 was for both of the studies > 300 mg/l. In these study was evaluated the presence or absence of turbidity, determined by bacterial growth.

The third study (Huntsman, 1984) was conducted according to internal method B-21. This method was based on oxygen consumption by activated sludge after 3 hours exposure to test item. The tested concentrations were: 10, 32 and 100 mg/l.. The IC50 was found to be more than 100 mg/l.

All of those studies demonstrate that the substance does not inhibit the oxygen uptake of activated sludge in concentrations higher or equal to 100 mg/l.