1,7-Naphthalenedisulfonic acid, 2-[[4-chloro-6-(cyanoamino)-1,3,5-triazin-2-yl]amino]-5-hydroxy-6-[2-[2-methoxy-5-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, lithium sodium salt (1:?:?)

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:

From Jul. 05, 1999 to Feb. 04, 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

Not applicable

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Direct weighing
- Incubation time: 3 h with permanent aeration

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Method of cultivation: aeration tank of a waste water treatment plant treating predominantly domestic sewage (Wupper area water authority)
- Pretreatment: None
- pH of the suspension before application: 6.6
- Test concentration of the activated sludge: 320 mg/L suspended solids

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

20±2 °C

pH:

7.3-7.8

Nominal and measured concentrations:

Nominal: 1000, 1800, 3200, 5600, 10000 mg/L

Details on test conditions:

Type of application: Direct weighing
Test concentration of the activated sludge: 320 mg/L suspended solids

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol (97 % purity)

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

4 250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

Test substance showed 77.3 % respiration inhibition of activated sludge at a test substance concentration of 10000 mg/L

Results with reference substance (positive control):

- Results with reference substance valid: Yes
- Ref. concentrations: 2.5, 5, 10, 20, 40 mg/L
- % Inhibition: 86.4 and 90.9 at 20 and 40 mg/L concentrations.
- EC50: 9.7 mg/L

Reported statistics and error estimates:

The EC values are determined by statistical methods (probit analysis).

Table 1. Results

Test concentration (mg/L)	Respiratory rate Test substance (mg/L. h)	Phys.-chem. O2-consumption (mg/L. h)	Respiratory rate Phys.-chem. O2-consumption (mg/L. h)	Inhibition (%)
1000	31.0	0.0*	31.0	6.1
1800	26.0	0.0*	26.0	21.2
3200	18.9	0.0*	18.9	42.7
5600	12.8	0.0*	12.8	61.2
10000	7.5	0.0	7.5	77.3
Control, Mean	33.0
Control 1	33.0
Control 2	33.0

 

* The physico chemical oxygen consumption is determined at 10000 mg/L test substance concentration. No physico-chemical oxygen consumption has been determined. Therefore lower concentrations of the test substance cause no physico chemical oxygen consumption (deduced values).

Validity criteria fulfilled:

yes

Conclusions:

Under the test conditions, the test substance showed 77.3 % respiration inhibition of activated sludge at a concentration of 10000 mg/L. The EC50 was determined to be 4250 mg/L.

Executive summary:

A study was performed to assess the toxicity of test substance to bacteria according to Commission Directive 88/3021EEC; Official Journal of the EC L133 Part C (1988) and equivalent to OECD Guideline 209 in compliance with GLP

 

The activated sludge was exposed to test substance at different concentrations. The respiration rate of each mixture was determined after aeration periods of 3 h. Test substance showed 77.31 % respiration inhibition of activated sludge at a concentration of 10000 mg/L. The EC50 was determined to be 4250 mg/L.

 

Under the test conditions, the test substance showed 77.3 % respiration inhibition of activated sludge at a concentration of 10000 mg/L. The EC50 was determined to be 4250 mg/L. 

Description of key information

The EC50 of the test substance was determined to be 4250 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:

4 250 mg/L

Additional information

A study was performed to assess the toxicity of test substance to bacteria according to Commission Directive 88/3021EEC; Official Journal of the EC L133 Part C (1988) and equivalent to OECD Guideline 209.

 

The activated sludge was exposed to test substance at different concentrations. The respiration rate of each mixture was determined after aeration periods of 3 h. Test substance showed 77.31 % respiration inhibition of activated sludge at a concentration of 10000 mg/L. The EC50 was determined to be 4250 mg/L.

 

The test substance showed 77.3 % respiration inhibition of activated sludge at a concentration of 10000 mg/L. The EC50 was determined to be 4250 mg/L (Dr. Muller, 2000).