Propanoic acid, 2-hydroxy-2-methyl-, 2-propen-1-yl ester

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

Instead of a centrifuged sludge a settled sludge was used.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

prop-2-en-1-yl 2-hydroxy-2-methylpropanoate

EC Number:

700-908-3

Cas Number:

19444-21-4

Molecular formula:

C7H12O3

IUPAC Name:

prop-2-en-1-yl 2-hydroxy-2-methylpropanoate

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

Activated sludge collection from the sewage treatment plant of CH-4153 Reinach on November 3, 1999.
The pH after collection was 7.7.
The preparation was carried out according to the method described in the guideline.
The sludge was separated from the aqueous layer by settling instead of centrifugation. The pH of the sludge before use was 7.9.
The sludge concentration in the test bottles was 1.75 g suspended solids/L.

Study design

Test type:

other: aeration

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Test temperature:

20 ± 2°c

pH:

The pH after collection was 7.7.
The pH before use was 7.9.

Nominal and measured concentrations:

Test item: 100.0, 32.0, 10.0, 3.2 and 1.0 mg/L
Reference item: 32.0, 10.0 and 3.2 mg/L

Details on test conditions:

Nutrient Solution:
16g Peptone
11g Meat extract
3.0g Urea
0.7g NaCL
0.4g CaCl2.2H2O
0.2g MgSO4.7H2O
2.8g K2HPO4
Were dissolved and the volume made up to one litre with de-chlorinated drinking water.

Vessels:
250 ml BOD flasks with gas inlet
Water:
De-chlorinated drinking water
Temperature:
20 ± 2 °C
Duration:
3 hours.

Stock solution:
200.8 mg test item were mixed and made up to 1000 ml with water.
The stock solution was freshly prepared at the start of the test.

Test concentrations:
Test item: 100.0, 32.0, 10.0, 3.2 and 1.0 mg/L
Reference item: 32.0, 10.0 and 3.2 mg/L

Test Concentrations:
Test item: 100.0, 32.0, 10.0, 3.2 and 1.0 mg/L
Reference item: 32.0, 10.0 and 3.2 mg/L
Calculated amounts of test item to produce the desired test concentrations were mixed with 114 ml water and 6.4 ml nutrient solution
(= test solution). Then 80 ml of the sludge were added. The test item, 6.4 ml of the nutrient solution, 114 ml water and 80 ml of the sludge were
mixed in 250 ml BOD flasks and aerated immediately.

Measurements:
Oxygen consumption per hour in mg/L with a ORION – Electrode Type 97-08, ORION Microprocessor Ionalizer 901 and plotted on a recorder.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The inhibitory effect of th tet item was expressed as a percentage of the mean respiration rates of two controls. Following values were calculated based on nominal concentrations:
The test item was tested at nominal concentrations of 1.0, 3.2, 10.0, 32.0 and 100 mg/L after a contact time of 3 hours. The calculation of the following effect concentrations was based on these nominal values.
EC50 (3h) : >100 mg/L
EC20 (3h) : >100 mg/L
EC80 (3h) : >100 mg/L

Results with reference substance (positive control):

For the reference item (tested nominal concentrations : 3.2, 10.0, 32.0 mg/L):
EC50 (3h) : >11.4 mg/L
EC20 (3h) : >4.1 mg/L
EC80 (3h) : >31.4 mg/L

Reported statistics and error estimates:

No error estimates reported

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC 50 (3h) for CA 2215 A in this test alone, is >100 mg/L. Based on the inherenttoxicity of CA 2215 A in this test, the test item can be classified as “not toxic to bacteria“.

Executive summary:

In the test with CA 2215 A the temperature was maintained constant at 20 ± 1°C. 

The pH of sludge was 7.7 after collection and 7.9 after preparation (before use). The pH of the mixtures in the test bottles was 8.2 – 8.3 at the end of exposure time. 

The EC50 (3h) of the reference item 3,5-Dichlorophenol was 11.4 mg/L. 

The inhibitory effect of the test item was expressed as a percentage of the mean respiration rates of two controls. Following values were calculated based on nominal concentrations:

EC50 (3h): > 100 mg/L

EC20 (3h): > 100 mg/L

EC80 (3h): > 100 mg/L

 

The EC 50 (3h) for CA 2215 A in this test alone, the test item can be classified as “not toxic to bacteria“.