Carbon black

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:

key study

Study period:

1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

other: Deutsche Einheitsverfahren zur Wasseruntersuchung (1975) DEV L3 (TTC Test)

Deviations:

yes

Remarks:

Control activity not reported. - % change from control is only parameter.reported

Principles of method if other than guideline:

Inhibition of dehydrogenase activity
2,3,5-Triphenyltetrazoliumchloride-Test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Suspensions of the test material at concentrations of 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8 g/L were prepared. The solution water was a mixture of chlorine-free drinking water, from Cologne, and deionised water, with a Ca:Mg ratio of 4:1.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

sewage plant Berg. Gladbach, dry weight: 5.2 g/l

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Remarks on exposure duration:

in dark

Post exposure observation period:

no

Hardness:

15°dH

Test temperature:

25°C

Salinity:

not applicable

Nominal and measured concentrations:

nominal

Details on test conditions:

As the substance tested is not water soluble, suspensions in chlorine-free water were used in the tests. Undissolved particles were observed.

Reference substance (positive control):

no

Key result

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

> 800 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: dehydrogenase activity

Details on results:

No effect on the dehydrogenase activity at any test concentration

Validity criteria fulfilled:

not specified

Conclusions:

Carbon black (Printex G) showed no effect on the dehydrogenase activity at any test concentration

Executive summary:

Carbon black is not toxic to aquatic microorganisms

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

other: Deutsche Einheitsverfahren zur Wasseruntersuchung (1975) DEV L3 (TTC Test)

Deviations:

yes

Remarks:

Filtration and equilibration procedure not reported. Control activity not reported. - % change from control is the only parameter reported

Principles of method if other than guideline:

dehydrogenase activity
2,3,5-Triphenyltetrazoliumchloride-Test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Details on inoculum:

sewage plant Berg. Gladbach, dry weight: 5.2 g/l

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Remarks on exposure duration:

in dark

Post exposure observation period:

no

Hardness:

15°dH

Test temperature:

25°C

pH:

pH = 7.5 +-0.1
The pH value was adjusted

Salinity:

not applicable

Nominal and measured concentrations:

nominal

Details on test conditions:

Because Carbon black is insoluble in water and for avoiding physical effects of the test material, filtrates of suspensions of Printex U were prepared at the concentrations of 10, 50, 100, 200, 400, 600, 800 mg/L and used in the test.

Reference substance (positive control):

no

Key result

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

> 800 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: dehydrogenase activity

Details on results:

Although Carbon black is insoluble in water and eluates were used in the test, concentrations above 200 mg/L increased the dehydrogenase activity (+6, +14, +15, +18). Possible reasons, e.g. impurities, are not described

Validity criteria fulfilled:

not specified

Conclusions:

Eluates from above 200 mg/l showed an increase in dehydrogenase activity.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

other: Deutsche Einheitsverfahren zur Wasseruntersuchung DEV L3 (TTC Test)

Principles of method if other than guideline:

Inhibition of dehydrogenase activity
2,3,5-Triphenyltetrazoliumchloride (TTC)-Test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Suspensions of the test material at concentrations of 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8 g/L were prepared. The solution water was a mixture of chlorine-free drinking water, from Cologne, and deionised water, with a Ca:Mg ratio of 4:1.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

sewage plant Berg. Gladbach, dry weight: 5.2 g/l

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Remarks on exposure duration:

in dark

Post exposure observation period:

no

Hardness:

15°dH

Test temperature:

25°C

Salinity:

not applicable

Nominal and measured concentrations:

nominal

Details on test conditions:

As the substance tested is not water soluble, suspensions in chlorine-free water were used in the tests. Undissolved particles were observed.

Reference substance (positive control):

no

Key result

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

> 800 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: dehydrogenase activity

Details on results:

Concentrations above 600 mg/L and 800 mg/L increased the activity of the dehydrogenases (+5%, +8%)

Control activity not reported. - % change from control is only parameter reported

Validity criteria fulfilled:

not specified

Conclusions:

Carbon black (Printex 400) showed no toxic effects on the dehydrogenase activity of microorganisms

Executive summary:

Carbon black is not toxic to aquatic microorganisms

Description of key information

Nanoforms of carbon black (no surface treatment) are not toxic to aquatic microorganisms. The EC0 values for several grades were all higher than 800 mg/L