7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid, sodium salt

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 1981-11-13 to 1981-11-25

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

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

RICHTLINIE 88/302/EWG (TEIL C), EG AMTSBLATT L 133/118 "BELEBTSCHLAMM: PRÜFUNG DER ATMUNGSHEMMUNG"

Deviations:

yes

Remarks:

Test volume 200 mL instead of 500 mL

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

- Concentrations: Stock solution 2 g/L
- Method: The test solution concentrations were performed dy dilution of the stock solution (Test concentrations: 500 and 1000 ppm (mg/L))
- Controls: blank control perfomed with the test solution without test substance and positive control performed with the reference substance 3,5 dichlorophenol.
- Evidence of undissolved material: no

Test organisms (species):

activated sludge

Details on inoculum:

- Laboratory culture: Municipal wastewater treatment plant in Frankfurt-Sindlingen
- Initial biomass concentration: Sludge Dry weight: 100 g of wet sludge in a 4.47 L (22.37 g/L)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 ± 1 °C

pH:

7

Salinity:

-

Nominal and measured concentrations:

Nominal concentrations: 0 (control) 500 and 1000 mg/L
Measured concentrations: No concentrations were measured.

Positive control: Nominal concentrations:
5, 20 , 30 mg/L

Details on test conditions:

TEST SYSTEM
- Type: closed
- Aeration: no
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: performed as follows:
90 mL of standard mud
+ 6.5 mL of synthetic wastewater
+ 3.5 mL of distilled water.
+ 100 mL of diluted test

Reference substance (positive control):

yes

Remarks:

3,5 dichlorophenol

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: >> 1000

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: >> 1000

Details on results:

The toxicity of Reactive Orange 72/78 on bacteria ("bacterial toxicity") was investigated in the oxygen-consumption inhibition test ("Robra test") with activated sludge as inoculum. After 3 hours the NOEC and the EC50 were determined to be greater than 1000 mg/L.

Results with reference substance (positive control):

The EC50 - value of the reference substance was determined to be < 20 mg/L.

Table 1: Inhibition of the respiration rate

mg/L	Activity (mg O2/L x h)	respiration/inhibition	mean
control 1	39	-	40.5
control 2	42	-	40.5
control 3	40.5	-	40.5
positive control (5)	24	40.7	-
positive control (20)	15	63	-
positive control (30)	13.5	66.7	-
1000 (A)	43.5	-7.4	-9.3
1000 (B)	45	-11.1	-9.3
500 (A)	42	-3.7	-1.9
500 (B)	40.5	0	-1.9

Validity criteria:

The audit was completed without problems, the EC50 - value of the reference substance was 5 to 30 mg / L. The deviation of the controls remained below the limit of 15%.

Validity criteria fulfilled:

yes

Conclusions:

The inhibition rate of oxygen consumption after 3 hours of exposure of bacteria to the test item gave the following results:
EC50: >> 1000 mg/L , NOEC (EC20): >1000 mg/L , EC 80: >> 1000 mg/L

Executive summary:

The toxicity of Reactive Orange 72/78 on bacteria ("bacterial toxicity") was investigated in the oxygen-consumption inhibition test ("Robra test") with activated sludge from municipal wastewater biological treatment Frankfurt / M - Sindlingen as inoculum. The provision of the inhibition rate of oxygen consumption after 3 hours of exposure to the test item on bacteria test gave the following results:  

Median inhibitory concentration, EC50: >> 1000 mg/L

NOEC, EC20 : >1000 mg/L

EC 80: >> 1000 mg/L

Description of key information

After 3 hours the EC 50 was determined to be greater than 1000 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

The toxicity of Reactive Orange 72/78 on bacteria ("bacterial toxicity") was investigated in the oxygen-consumption inhibition test ("Robra test") with activated sludge from municipal wastewater biological treatment Frankfurt / M - Sindlingen as inoculum. The provision of the inhibition rate of oxygen consumption after 3 hours of exposure to the test item on bacteria test gave the following results: 

Median inhibitory concentration, EC50: >> 1000 mg/L

NOEC, EC20 : >1000 mg/L

EC80: >> 1000 mg/L