Allyl (3-methylbutoxy)acetate

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

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 (Carbon and Ammonium Oxidation))

Version / remarks:

adopted 22 July 2010

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not specified

Vehicle:

no

Details on test solutions:

Preparation of Test Mixtures

The weighed quantity of test item was added directly into the test vessels to obtain different nominal concentrations of the test item. During the start of the test, 16 mL synthetic sewage was added and volume was made up to 250 mL using distilled water. Further, 250 mL of activated sludge
(3 g/L) was added to make up the final volume as 500 mL.

Test organisms (species):

activated sludge

Details on inoculum:

6.1.3 Inoculum
Source of inoculum (activated sludge) was Sewage Treatment Plant, Eurofins Advinus Limited, Bengaluru, India.

The inoculum was collected from the exit of the aeration tank of well operated wastewater treatment plant receiving predominantly domestic sewage. The sludge was allowed to settle for 15 minutes and upper layer of finer solids was decanted. The collected sludge was centrifuge at least for 10 minutes at 3000 rpm and supernatant liquid was discarded. Then sludge was suspended in distilled water with shaking and re-centrifuge to remove wash-water and was discarded. Washing and centrifuging procedure was repeated three times.

A sample of washed sludge was weighed in triplicate and dried at 150 °C in oven for 1 hour. From the obtained result the quantity of sludge required to obtain an activated sludge concentration of 3 g/L was calculated. During range finding test, 63.09 g sludge was suspended in distilled water to make 3 L and 122.22 g sludge was suspended in distilled water to make 6 L during definitive test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Remarks on exposure duration:

3 h incubation + 10 minutes measurement

Test temperature:

20-22 C

pH:

pH: 7.9-8.51

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

ca. 8.47 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

Range Finding Test

The pH, oxygen consumption rate, specific respiration rate and per cent inhibition, total respirations are presented in Table 3.

The pH of the mixtures after 3 h incubation ranged from 7.99 to 8.58.

The calculated per cent inhibition of Allyl Amyl Glycolate, total respiration was 79.6, 84.6 and 98.5%; heterotrophic respiration was 87.4, 88.9 and 97.6%, respectively. Since nitrification respiration rate was found to be not significant (significance was 2.83 %) the inhibition of Allyl Amyl Glycolate due to nitrification respiration was not calculated.

There was no oxygen uptake in the abiotic control at the highest test item concentration of 1000 mg/L.

Definitive test
The pH of the mixtures after 3 h incubation ranged from 7.90 to 8.51.

The calculated per cent inhibition of Allyl Amyl Glycolate, total respiration was 1.5, 48, 54.6, 64.9 and 77.2 % and heterotrophic respiration was 2.8, 41.9, 57.8, 59.1 and 67.5 %, respectively. Since nitrification respiration rate was found to be not significant (significance was 1.25%), the inhibition of Allyl Amyl Glycolate due to nitrification respiration was not calculated.

The EC50 value of Allyl Amyl Glycolate, total respiration inhibition is 8.47 mg/L with fiducial limits at 95% ranging from 2.539 to 31.95 mg/L.

The EC50 value of Allyl Amyl Glycolate, heterotrophic respiration inhibition is 10.24 mg/L with fiducial limits at 95% ranging from 2.054 to 29.672 mg/L.

Results with reference substance (positive control):

The calculated per cent inhibition, total respiration of reference substance, 3,5-Dichlorophenol was 31.3, 70.3 and 96.4 % and heterotrophic respiration was 25.3, 49.7 and 98.4 % at the tested concentrations of 2, 8 and 32 mg/L, respectively.


The EC50 value of 3,5-Dichlorophenol, total respiration inhibition is 3.87 mg/L with fiducial limits at 95% ranging from 3.082 to 4.851 mg/L.

The EC50 value of 3,5-Dichlorophenol, heterotrophic respiration inhibition is 5.76 mg/L with fiducial limits at 95% ranging from 2.162 to 14.256 mg/L.

Reported statistics and error estimates:

See it in the attached full report.

Validity criteria fulfilled:

yes

Conclusions:

The EC50value,total respiration inhibition and heterotrophic respiration inhibition of Allyl Amyl Glycolate is 8.47 and 10.24 mg/L.

Executive summary:

The EC₅₀value,total respiration inhibition andheterotrophic respirationinhibition of Allyl Amyl Glycolate is 8.47 and 10.24 mg/L.

RESULTS AND DISCUSSION

Range Finding Test

The pH, oxygen consumption rate, specific respiration rate and per cent inhibition, total respirations are presented in Table 3.

The pH of the mixtures after 3 h incubation ranged from 7.99 to 8.58.

The calculated per cent inhibition of Allyl Amyl Glycolate, total respiration was 79.6, 84.6 and 98.5%; heterotrophic respiration was 87.4, 88.9 and 97.6%, respectively.  Since nitrification respiration rate was found to be not significant (significance was 2.83 %) the inhibition of Allyl Amyl Glycolate due to nitrification respiration was not calculated.

There was no oxygen uptake in the abiotic control at the highest test item concentration of 1000 mg/L.

Definitive Test

The pH, oxygen consumption rate and per cent inhibition, total,  and heterotrophic respirations are presented in Tables 4 and 5, respectively.

The pH of the mixtures after 3 h incubation ranged from 7.90 to 8.51.

The calculated per cent inhibition of Allyl Amyl Glycolate, total respiration was 1.5, 48, 54.6, 64.9 and 77.2 % and heterotrophic respiration was 2.8, 41.9, 57.8, 59.1 and 67.5 %, respectively. Since nitrification respiration rate was found to be not significant (significance was 1.25%), the inhibition of Allyl Amyl Glycolate due to nitrification respiration was not calculated.

The EC50 value of Allyl Amyl Glycolate, total respiration inhibition is 8.47 mg/L with fiducial limits at 95% ranging from 2.539 to 31.95 mg/L.

The EC50 value of Allyl Amyl Glycolate, heterotrophic respiration inhibition is 10.24 mg/L with fiducial limits at 95% ranging from 2.054 to 29.672 mg/L.

The calculated per cent inhibition, total respiration of reference substance, 3,5-Dichlorophenol was 31.3, 70.3 and 96.4 % and heterotrophic respiration was 25.3, 49.7 and 98.4 % at the tested concentrations of 2, 8 and 32 mg/L, respectively.

Dose response curves of reference substance refer Figures 1 to 4.

The EC50 value of 3,5-Dichlorophenol, total respiration inhibition is    3.87 mg/L with fiducial limits at 95% ranging from 3.082 to 4.851 mg/L.

The EC50 value of 3,5-Dichlorophenol, heterotrophic respiration inhibition is 5.76 mg/L with fiducial limits at 95% ranging from 2.162 to 14.256 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

8.47 mg/L