m-toluidine

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

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

Test organisms (species):

other: other bacteria: activated sludge (from 3L laboratory plant, OECD)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

21.6-20.2°C

pH:

7.4-8.6

Nominal and measured concentrations:

nominal: 100, 1000, 10000 mg/L

Details on test conditions:

Type: aquatic

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorphenol

Duration:

3 h

Dose descriptor:

other: EC05

Effect conc.:

437 mg/L

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

1 572 mg/L

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

580 mg/L

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

3,5-Dichlorphenol:
conc. 1.0 mg/L =7.1% inhibition,
conc. 20 mg/L = 78.6% inhibition

Reported statistics and error estimates:

statistical method: probit analysis

Validity criteria fulfilled:

yes

Remarks:

Validation of the test was verified by graphic evaluation of the reference substance.

Conclusions:

A 3h-EC50 of 1572 mg/L was observed on the respiration of activated sludge.

Executive summary:

The toxicity of m-toluidine towards microorganisms was investigated according to OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test) observing the respiration of activated sludge. On that basis, an EC10(3 h) of 580 mg/L and an EC50 of 1572 mg/L were determined.

Reference 2

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance with national standard method with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

Principles of method if other than guideline:

German standard methods for the examination of water, wastewater and sludge; bioassay (group L); determination of the biological effects of the toxic wastewater on bacteria L8 (1968) modified

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

Pseudomonas putida

Test type:

static

Limit test:

no

Total exposure duration:

18 h

Test temperature:

25°C

Details on test conditions:

- growth inhibition was determined based on the measurement of monochromatic light at a wave length of 436 nm

Duration:

18 h

Dose descriptor:

EC10

Effect conc.:

151 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Validity criteria fulfilled:

not specified

Remarks:

Since the test is poorly reported the validity criteria cannot be assessed sufficiently. Nevertheless the test is considered as valid based on the data given.

Conclusions:

On Pseudomonas putida m-toluidine revealed a 18h-EC10 of 157 mg/L.

Executive summary:

The toxicity of m-toluidine toward microorganisms was determined testing Pseudomonas putida. A 18h-EC10 of 151 mg/L (nominal) was received.

Reference 3

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Basic data given.

Principles of method if other than guideline:

Method following the protocol described by Schultz (1996) investigating growth impairment of ciliate Tetrahymena pyriformis after an exposure duration of 40 h (Tetrahymena in aquatic toxicology: QSARs and ecological hazard assessment. In: Proceedings of the International workshop on a protozoan test protocol with Tetrahymena in aquatic toxicity testing (Pauli & Berger, Eds.), pp 31-66.)

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Tetrahymena pyriformis

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

40 h

Test temperature:

27 +/- 1 °C

pH:

7.35

Details on test conditions:

Type: aquatic
TEST SYSTEM
- Test vessel: foam stoppered 250 mL Erlenmeyer flask
- No. of vessels per concentration (replicates): six to eight, range finding studies were performed previously
- No. of vessels per control (replicates): two
- the chemical is evaluated three times using freshly prepared stock solutions, each test was set up in duplicate


TEST MEDIUM
- media consists of distilled water, proteose peptone, glucose, yeast extract, TRIS-HCl, CaCl2, CuCl2, FeCl3, MgSO4, Fe(NH4)2(SO4)2, MnCl2, ZnCl2
- the media has to be sterilized prior to test begin



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
population density was measured spectrophotometrically at 540 nm

Duration:

40 h

Dose descriptor:

IC50

Effect conc.:

204 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Result is given in log IGC50 = 0.28. 
IG = Impairment of (population) growth
The result equals 1.91 mmol/l or 204 mg/L

Validity criteria fulfilled:

not specified

Remarks:

Since the test is poorly reported the validity criteria cannot be assessed sufficiently. Nevertheless the test is considered as valid based on the data given

Conclusions:

For m-toluidine an IGC50 (inhibitory growth concentration) of 204 mg/L was received.

Executive summary:

The toxicity of m-toluidine toward microorganisms was determined testing Tetrahymena pyriformis. An IGC50 (inhibitory growth concentration) of 204 mg/L (nominal) was determined after a test duration of 40 h (Schultz, 1998).

Description of key information

Regarding all available test on toxicity to microorganisms, the most relevant test resulting in the lowest PNEC value is used for assessment.
In order to protect the efficiency of sewage treatment plants, the ciliate growth inhibition test is identified to be the most sensitive test system.
For the substance a  40h-EC50 of 204 mg/L was obtained towards Tetrahymena pyriformis.

Key value for chemical safety assessment

EC50 for microorganisms:

204 mg/L

Additional information

Several tests are available to evaluate the toxicity of m-toluidine to microorganisms.

The toxicity of m-toluidine to Tetrahymena pyriformis was tested in a 40 hours test using the population growth inhibition as endpoint. An EC50 of 204 mg/L was observed.

In another test, the toxicity of m-toluidine towards microorganisms was investigated observing the respiration of activated sludge. On that basis, an EC10(3 h) of 580 mg/L and an EC50 of 1572 mg/L were determined. The test was carried out according to OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test).

Further, the toxicity of m-toluidine towards microorganisms was determined testing Pseudomonas putida. The test was performed according to German standard methods for the examination of water, wastewater and sludge; bioassay (group L), the DIN 38412, part 8 (Pseudomonas Zellvermehrungshemm-Test). A 18h-EC10 of 151 mg/L (nominal) was received. According to the ECHA guidance on information requirements and chemical safety assessment, Chapter R.10: Characterisation of dose[concentration]-response for environment (May 2008), this test should be used only, if no other tests are available. Thus, this test is not taken into account for PNEC derivation as other test results are available.