4-(phenylazo)benzene-1,3-diamine

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

growth inhibition effect on activated sludge microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Justification for type of information:

Data is from peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

The growth inhibition effect of the test substance 4-(phenylazo)benzene-1,3-diamine on activated sludge microorganisms was studied.

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

yes

Remarks:

2 % aqueous ethanol solution

Details on test solutions:

Test concentration: 0.17 m.mole/L (maximum experimental concentration)

Test organisms (species):

activated sludge

Details on inoculum:

The mixed microorganisms were obtained from supernatant of activated sludge and pre-incubated with the medium without azo compounds for 2 days. The microorganisms were inoculated to the experimental medium to give the optical density of the culture at 0.02-0.05. Incubation temperature was at 25±1 deg. C

Test type:

static

Water media type:

freshwater

Remarks on exposure duration:

Not specified

Post exposure observation period:

Not specified

Hardness:

Not specified

Test temperature:

25±1 deg. C

pH:

Not specified

Dissolved oxygen:

Not specified

Salinity:

Not specified

Conductivity:

Not specified

Nominal and measured concentrations:

Test concentration: 0.17 m.mole/L (maximum experimental concentration)

Details on test conditions:

Culture Medium is as follows:
Glucose: 500 ppm
Peptone: 500 ppm
KH2PO4:0 270 ppm
K2HPO4: 100 ppm
Na2HPO4: 660 ppm
MgSO4. 7H20: 2 ppm
CaCI2: 0.0200 ppm
FeSO4. 7H20: 0.0200 ppm
in 2 % aqueous ethanol solution

Reference substance (positive control):

not specified

Key result

Dose descriptor:

other: IGC50

Effect conc.:

0.087 mmol/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Remarks on result:

other: duration not specified

Details on results:

Not specified

Results with reference substance (positive control):

Not specified

Reported statistics and error estimates:

Not specified

50 % Growth Inhibition Concentrations (Ø) of test substance:

Compound	Medium	log Ø	log C	log Poct
2,4-DIAMINOAZOBENZENE [4-(phenylazo)benzene-1,3-diamine]	e	-1.056	-0.752	2.19

 

Ø; concentration of 50 % growth inhibition (m.mole/l.)
C; maximum experimental concentration (m.mole/l.)
Poct; partition coefficient between octanol and water
e; 2 % aqueous ethanol solution

Validity criteria fulfilled:

not specified

Conclusions:

50 % growth inhibition concentration (IGC50) of the test substance 4-(phenylazo)benzene-1,3-diamine on mixed culture of microorganisms was observed to be 0.087 m.mole/L. The study concludes that the test substance showed strong growth inhibition effect on the microorganisms.

Executive summary:

In order to evaluate the effect of test substance 4-(phenylazo)benzene-1,3-diamine on the biological waste treatment, the growth inhibition effect of it on activated sludge microorganisms was studied. Growth inhibition effect was evaluated by the concentration of test compound in which logarithmic phase growth rate constant was decreased to 50 % of that of the culture without test compound. Growth rate constant was determined with turbidity of that of the culture at 660 nm. The mixed microorganisms were obtained from supernatant of activated sludge and pre-incubated with the medium without azo compounds for 2 days. The microorganisms were inoculated to the experimental medium to give the optical density of the culture at 0.02-0.05. Incubation temperature was at 25±1 deg C. 50 % growth inhibition concentration (IGC50) of the test substance 4-(phenylazo)benzene-1,3-diamine on mixed culture of microorganisms was observed to be 0.087 m.mole/L. The study concludes that the test substance showed strong growth inhibition effect on the microorganisms.

Description of key information

50 % growth inhibition concentration (IGC50) of the test substance 4-(phenylazo)benzene-1,3-diamine on mixed culture of microorganisms was observed to be 0.087 m.mole/L. The study concludes that the test substance showed strong growth inhibition effect on the microorganisms.

Additional information

In order to evaluate the effect of test substance 4-(phenylazo)benzene-1,3-diamine on the biological waste treatment, the growth inhibition effect of it on activated sludge microorganisms was studied. Growth inhibition effect was evaluated by the concentration of test compound in which logarithmic phase growth rate constant was decreased to 50 % of that of the culture without test compound. Growth rate constant was determined with turbidity of that of the culture at 660 nm. The mixed microorganisms were obtained from supernatant of activated sludge and pre-incubated with the medium without azo compounds for 2 days. The microorganisms were inoculated to the experimental medium to give the optical density of the culture at 0.02-0.05. Incubation temperature was at 25±1 deg C. 50 % growth inhibition concentration (IGC50) of the test substance 4-(phenylazo)benzene-1,3-diamine on mixed culture of microorganisms was observed to be 0.087 m.mole/L. The study concludes that the test substance showed strong growth inhibition effect on the microorganisms.