Reaction mass of methyl acetate and methanol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Reason / purpose for cross-reference:

read-across source

Nominal and measured concentrations:

not specified

Duration:

30 min

Dose descriptor:

EC10

Effect conc.:

1 730 mg/L

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

6 100 mg/L

Reference 2

Endpoint:

toxicity to microorganisms, other

Remarks:

cell multiplication inhibition test

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

16 h

Dose descriptor:

other: TGK (Toxikologische Grenzkonzentration), toxicological threshold value

Effect conc.:

6 600 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Reference 3

Endpoint:

toxicity to microorganisms, other

Remarks:

cell multiplication inhibition test

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

192 h

Dose descriptor:

other: TGK (Toxikologische Grenzkonzentration); toxicological threshold value

Effect conc.:

530 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Reference 4

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Reference 5

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:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Sampling method: a portion of a reaction mixture was transferred to a standard BOD dilution bottle.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Stock solutions (0.5 to 5.0 g/L) of the test chemical were prepared in deionized water. When necessary, the stock solutions were adjusted to pH 7.5 ± 0.5 by the addition of 1N H2SO4 or 1N NaOH as required

Test organisms (species):

other: activated sludge from domestic and industrial sewage treatment plants

Details on inoculum:

Activated sludge was obtained on the day prior to the first day of each series of inhibition tests. On return to the laboratory, the solids were allowed to settle and the waste liquor was discarded. The solids were then transferred into a 9-liter laboratory-scale, semi-continuous activated sludge cylinder and diluted to approximately 8.5 liters with deionized water. The system was initially mixed by aerating at a rate of approximately 0.5 L/min, and the concentration of mixed liquor suspended solids was determined by gravimetric analysis. The solids were then allowed to settle in the cylinder and the upper layer of waste liquor was discarded. The activated sludge was washed three times with appropriate volumes of deionized water. After washing, the system was adjusted to contain 4000 ± 400 mg of mixed liquor suspended solids (dry weight) per liter. The system was then aerated continuously at a rate of 0.5 L/min and incubated at ambient temperature (21°C).
The system was supplemented daily with 50 mL of a synthetic sewage stock solution per litter of activated sludge. The synthetic sewage stock solution was composed of, per liter: Bacto-Peptone, 16.0 g; Bacto-Beef extract, 11.0 g; urea 3.0 g; K2HPO4, 28 g; MgSO4 • 7H2O, 0.2 g; CaCl2 • 2H2O, 0.4 g; and NaCl, 0.7 g. Final pH of the stock solution was adjusted to pH 7.0 with H3PO4. Fresh stock solution was prepared as required and stored for not more than two days at 5°C.
When the same source of inoculum was to be used for testing on a subsequent day (maximum of 7 days). an additional 50 mL of synthetic sewage stock solution was added per liter of activated sludge. The system was incubated overnight.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

21°C

pH:

7.4 - 8.0

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 1L-bottle, final volume 500 mL
- Aeration: 0.5 - 1.0 L/min

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water

OTHER TEST CONDITIONS
- Adjustment of pH: yes, 7.5 ± 0.5

Reference substance (positive control):

yes

Remarks:

3,5-dichlorphenol

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Details on results:

During a number of preliminary inhibition studies, it was observed that the pH of a test reaction often changed during the 3-hour incubation period. Thus, decreases in the respiration rate may have been due to a combination of both the effects of pH and toxicity of the test chemical. As a consequence, the buffering capacity of the synthetic sewage nutrient medium was increased to prevent changes in pH of reaction mixtures.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: IC50 for 3,5-dichlorphenol: 12.2 ± 2.2 mg/L (18% variance) (municipal sewage), 11.4 ± 1.5 mg/L (13% variance) (industrial sewage)

Reported statistics and error estimates:

Inhibition data were analyzed using Thompson's method of moving averages to estimate IC50 values. The experimental data were also analyzed using a probit-transformation model similar to that described by Larson and Schaeffer (1982). A nonlinear curve-fitting program (Procedure NLIN of SAS) was used to estimate IC50 values and associated 95% confidence intervals.

Validity criteria fulfilled:

not specified

Conclusions:

In an Activated Sludge, Respiration Inhibition Test according to OECD Guideline 209 the 3-hour IC50 (growth inhibition) of Methanol was determined to be >1000 mg/L. 

Executive summary:

The toxic effect of methanol to microorganisms was assessed in a 3-hour Activated Sludge, Respiration Inhibition Test according to OECD Guideline 209. For the assay activated sludge from domestic and industrial sewage treatment plants was used. Test reaction mixtures were prepared by adding 16 mL of synthetic sewage stock solution and the desired amount of the test chemical to a 500 mL graduated cylinder. The mixture was diluted to a volume of 300 mL with deionized water. Activated sludge inoculum (200 mL) containing approximately 800 mg of suspended solids (dry weight) was then added and the contents of the cylinder (final volume of 500 mL) were transferred to a 1-liter bottle. The reaction mixture was aerated to ensure complete mixing using a Pasteur pipette aeration device. Reaction mixtures were typically prepared at 15 minute intervals. The suitability of the test system was verified by a positive control with the reference substance 3,5-dichlorphenol. During a number of preliminary inhibition studies, it was observed that the pH of a test reaction often changed during the 3-hour incubation period. Thus, decreases in the respiration rate may have been due to a combination of both the effects of pH and toxicity of the test chemical. As a consequence, the buffering capacity of the synthetic sewage nutrient medium was increased to prevent changes in pH of reaction mixtures. In result, the 3-hour IC50 (growth inhibition) was determined to be >1000 mg/L. 

Reference 6

Endpoint:

toxicity to microorganisms, other

Remarks:

cell multiplication inhibition test

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Growth inhibition test. The toxicity threshold of methanol for Microcystis aeruginosa was determined in the cell multiplication inhibition test.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Microcystis aeruginosa

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

192 h

Test temperature:

27°C

Key result

Duration:

192 h

Dose descriptor:

other: TGK (Toxikologische Grenzkonzentration); toxicological threshold value

Effect conc.:

530 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Validity criteria fulfilled:

not specified

Conclusions:

In a cell multiplication inhibition test with Microcystis aeruginosa the toxicity threshold (192 hours) of methanol was determined to be 530 mg/L (based on grwoth inhibition).

Reference 7

Endpoint:

toxicity to microorganisms, other

Remarks:

cell multiplication inhibition test

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Growth inhibition test. The toxicity threshold of methanol for Pseudomonas putida (bacteria) was determined in the cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Pseudomonas putida

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test temperature:

25°C

Reference substance (positive control):

not specified

Key result

Duration:

16 h

Dose descriptor:

other: TGK (Toxikologische Grenzkonzentration), toxicological threshold value

Effect conc.:

6 600 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Validity criteria fulfilled:

not applicable

Conclusions:

In a 16-hour cell multiplication inhibition test with Pseudomonas putida the 16-hour toxicological threshold value (based on growth inhibition) was determined to be 6600 mg/L

Reference 8

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

Study by a recognized state-owned laboratory, testing according to standardized laboratory guidelines

Principles of method if other than guideline:

Mikrotoxtest (not further specified)

GLP compliance:

not specified

Analytical monitoring:

not specified

Details on sampling:

not specified

Vehicle:

not specified

Details on test solutions:

not specified

Test organisms (species):

Photobacterium phosphoreum

Details on inoculum:

not specified

Test type:

static

Water media type:

saltwater

Hardness:

not specified

Test temperature:

not specified

pH:

not specified

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

not specified

Details on test conditions:

Type: aquatic

Reference substance (positive control):

not specified

Duration:

30 min

Dose descriptor:

EC10

Effect conc.:

1 730 mg/L

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

6 100 mg/L

Validity criteria fulfilled:

yes

Conclusions:

In a static "Mikrotoxtest" with Photobacterium phosphoreum a EC10 and EC50 (16h) of 1730 mg/L and 6100 mg/L, respectively, was determined. 

Executive summary:

Photobacterium phosphoreum:

EC 50 (16h): 6100 mg/l

EC 10 (16 h): 1730 mg/l

Description of key information

Based on a read across to the structural analogue Methanol (CAS 67 -56 -1) the IC50 of the registrations substance was determined to be >1000 mg/L.

Additional information

No data on toxicity to microorganisms are available for the registration substance itself, but for the read across source substances Methanol and Methyl acetate.

Key information

The toxic effect of methanol to microorganisms was assessed in a 3-hour Activated Sludge, Respiration Inhibition Test according to OECD Guideline 209 (Klecka et al., 1985). For the assay activated sludge from domestic and industrial sewage treatment plants was used. Test reaction mixtures were prepared by adding 16 mL of synthetic sewage stock solution and the desired amount of the test chemical to a 500 mL graduated cylinder. The mixture was diluted to a volume of 300 mL with deionized water. Activated sludge inoculum (200 mL) containing approximately 800 mg of suspended solids (dry weight) was then added and the contents of the cylinder (final volume of 500 mL) were transferred to a 1-liter bottle. The reaction mixture was aerated to ensure complete mixing using a Pasteur pipette aeration device. Reaction mixtures were typically prepared at 15 minute intervals. The suitability of the test system was verified by a positive control with the reference substance 3,5-dichlorphenol. During a number of preliminary inhibition studies, it was observed that the pH of a test reaction often changed during the 3-hour incubation period. Thus, decreases in the respiration rate may have been due to a combination of both the effects of pH and toxicity of the test chemical. As a consequence, the buffering capacity of the synthetic sewage nutrient medium was increased to prevent changes in pH of reaction mixtures. In result, the 3-hour IC50 (growth inhibition) of Methanol was determined to be >1000 mg/L. 

In a 16-hour cell multiplication inhibition test with Pseudomonas putida the 16-hour toxicological threshold value (based on growth inhibition) was determined to be 6600 mg/L (Bringmann and Kuehn, 1977). In another cell multiplication inhibition test with Microcystis aeruginosa the toxicity threshold (192 hours) of methanol was determined to be 530 mg/L (based on growth inhibition).

Methyl acetate

In a static "Mikrotoxtest" with Photobacterium phosphoreum a EC10 and EC50 (16h) of 1730 mg/L and 6100 mg/L, respectively, was determined (Steinhäuser, 1989). 

Conclusion

Steinhäuser (1989) carried out a "Mikrotoxtest" with Methyl acetate and derived a EC10 and EC50 (16h) of 1730 mg/L and 6100 mg/L, respectively. Bringmann and Kuehn (1978) determined a toxic threshold value (TGK) of 530 mg/L in a 192-hour test with Microcystis aeruginosa. The same authors report a further toxic treshold value resulting from a cell multiplication test for 16 hours, using two Pseudomonas species, at 6600 mg/L (Bringmann and Kuehn 1977). An IC50 value >1000 mg/L for activated sludge is reported by Klecka et al. (1985). This test was performed according to the OECD Guideline 209 (activated sludge, respiration inhibition test) and is considered the most appropriate for assessing the risk for wastewater treatment plant.