2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-, coupled with 3-aminophenol, diazotized 5-amino-2-[(4-aminophenyl)amino]benzenesulfonic acid and diazotized benzenamine, sodium salts

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

adopted April 4th, 1984

GLP compliance:

yes

Test organisms (species):

activated sludge

Details on inoculum:

- Test organism: mixture culture of bacteria )sludge of a Husman apparatus).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

19.5 °C

Nominal and measured concentrations:

Nominal: 1, 3.2, 10, 32 and 100 mg/l

Details on test conditions:

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2

EFFECT PARAMETERS MEASURED: oxygen consumption, measured with an oxygen-sensitive electrode system: OXI DIGI 530.
The respiration rate of each test concentration was calculated as a percentage of the mean of the two control respiration rate. The results were plotted on a log (concentration) / normal (% inhibition) graph and the IC50 value was derived.

Reference substance (positive control):

yes

Remarks:

3,5 - Dichlorophenol

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

IC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

No inhibition was recorded up to the highest concentration tested.

Results with reference substance (positive control):

IC50 of 3,5 - Dichlorophenol: 16 mg/l.

Bacteria inhibition (IC50) at 3 hours - Oxygen consumption tests

Test substance (mg/l)	3 h
	Oxygen consumption (mg/l/min)	Inhibition (%)
100	1.80	0
32	1.70	0
10	1.74	0
3.2	2.80	0
1	2.00	0
Control (K1)	1.72	mean: 1.68
Control (K2)	1.63
3,5- Dichlorophenol (mg/l)
100	0.13	92.3
32	0.19	88.7
10	1.27	24.4

Validity criteria fulfilled:

yes

Remarks:

The two control respiration rates do not differ more than 15 % and the EC50 of the reference item is in the range of 54 -146 mg/l.

Conclusions:

IC50 (3h) > 100 mg/l (nominal)

Executive summary:

The inhibitory effect of the substance to the microorganisms was assessed according to OECD guideline 209. The substance, tested in five different concentrations, was in contact with a mixed culture of a Husman apparatus. In parallel, two controls non containing the substance and a positive control, containing the reference substance run in parallel. After 3 hours, the oxygen consumption was measured in all the tested solutions, control and positive control. The log concentration-inhibition percentage was presented in a graph and the IC50 was interpolated from the graph.

No inhibition was recorded up to the highest concentration tested.

Conclusion

IC50 (3h) > 100 mg/l (nominal)

Description of key information

Non toxic to microorganisms

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

The inhibitory effect of the substance to the microorganisms was assessed according to OECD guideline 209. The substance, tested in five different concentrations, was in contact with a mixed culture of a Husman apparatus. In parallel, two controls non containing the substance and a positive control, containing the reference substance run in parallel. After 3 hours, the oxygen consumption was measured in all the tested solutions, control and positive control. The log concentration-inhibition percentage was presented in a graph and the IC50 was interpolated from the graph. No inhibition was recorded up to the highest concentration tested.