2-phenoxyethyl methacrylate

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:

2012.02.20

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Boiling point: 134 degrees celcius (1 mmHg)
- Density: 1.104g/cm3
- log Pow:2.46 (estimated)
- pH : 6-8
- Flash point: 170 degrees celcius

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

A stock solution of 279 mg/L was prepared by weighing out 558.3 mg/L of the test item and adding Milli-Q water to 2,000 mL. The stock solution was used for preparing a dilution series of the test item. Concentrations were selected on the basis of a preliminary range finding test and determination of the solubility of the test item in Milli-Q water.

Test organisms (species):

activated sludge

Details on inoculum:

Activated sludge was collected from Nivå waste water treatment plant. Sludge was seperated from the waterphase by centrifugation (approx. 15,000 m/sec2) The sludge was the resuspended in tap-water. The sludge was sieved through a 1-mm sieve and finally resuspended in tap-water. the concentration of suspended solids (SS) in the resuspended sludge was determined in DS/EN 872 to be 20.2 g/L. The activated sludge was aerated until use.
A preliminary estimation of the respiration rate of the sludge (10% sludge+10% synthetic sewage medium and Milli-Q water was found to be 45 mgO2*L-1 corresponding to 22 mg O2*gSS-1*h-1).

Final sludge concentration in the mixtures were 1.75 to 1.97 g SS/L

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Post exposure observation period:

na

Hardness:

na

Test temperature:

20.1-21.6 degrees celcius

pH:

na

Dissolved oxygen:

na

Salinity:

na

Nominal and measured concentrations:

na

Details on test conditions:

500-mL Erlenmeyer flasks were used as mixing vessels. Each vessel contained a total test mixture volume of 400 mL. One by one the test mixtures were transferred from the mixing vessels to a 300-mL BOD bottle. An oxygen electrode, which was mounted in a stopper fitting in the neck of the BOD bottle and connected to an oxygen meter (WTW Inolab Oxi 740P) was immediately placed in the bottle and the mixture gently stirred.

Mixtures employd were:
control
test suspension
reference
abiotic control
The test was performed in a temperature regulated room

Reference substance (positive control):

yes

Remarks:

3,5-DCP

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

177 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

Results from the reference test with 3,5 dichlorophenol:
EC20 (30 min.) = 2.4 mg/L
EC50 (30 min.) = 11.0 mg/L
EC20 (180 min. ) = 1.2 mg/L 
EC50 (180 min.) = 8.5 mg/L

Reported statistics and error estimates:

In accordance with ISO 8192, the concentrations of the test item and the reference substance 3,5 DCP, inhibiting the respiration rate by 20% and 50 % were estimated by use of the computer program TOXEDO and expressed as EC20 and EC50

Effect concentrations obtained in the activated sludge respiration inhibition test with 2 -phenoxyethyl acrylate and the reference substance 3,5 DCP.

Test item	Concentration mg/L
	Contact time 30 min.		Contact time 180 min.
	EC20	EC50	EC20	EC50
2 -phenoxyethyl acrylate	57 (38 -74)	241 (88 -356)	59 (33 -79)	177 (141 -248)
3,5 dichlorophenol	2.4	11.0	1.2	8.5

The sensitivity of the activated sludge was verified by testing the inhibitory effect of the reference substance 3,5 DCP. The EC50 values of 11.0 mg/L (30 min.) and 8.5 mg/L (180 min.) showed that the sensitivity of the activated sludge was in the range normally obtained in an interlaboratory trial carried out in July 2004: EC50 9.8 mg/L (7.1 -12.6) (30 min) and 9.3 mg/L (7.2 -11.3) (180 min.)

Validity criteria fulfilled:

no

Remarks:

The validity criteria of an oxygen uptake rate >/= 20 mg/g dry weight sludge per hour was not fullfilled.

Conclusions:

Based on the results obtained, the effect of 2-phenoxyethyl acrylate on the total respiration of activated sludge organisms (using the ISO International standard 8192 (corresponding to OECD 209 apart from a few deviations)) was determined to be:
3,5 dichlorophenol:
EC20 (30 min.) 2.4 mg/L
EC50 (30 min.) 11.0 mg/L
EC20 (180 min) 1.2 mg/L
EC50 (180 min.) 8.5 mg/L

Executive summary:

The effect of 2-phenoxyethyl acrylate on the total respiration of activated sludge organisms (using the ISO International standard 8192 (corresponding to OECD Guideline no. 209 apart from a few deviations)) was tested.

2-phenoxyethyl acrylate was tested at the following concentrations 0 (control); 15; 30; 60; 120; 240 mg/L.

The effect concentrations obtained in the test were: EC20 (30 min) = 57 mg/L; EC50 (30 min) = 241 mg/L; EC20 (180 min) = 59 mg/L; EC50 (180 min.) = 177 mg/L.

Validity:

The validity criteria of an oxygen uptake rate >/= 20 mg/g dry weight sludge per hour was not fullfilled. However since the preliminary screening of the uptake rate in the sludge was meassured to be 22 mg/g of dry sludge per hour and the rate in the test and the rate in the test after 30 minutes was very close to 20 mg/g (19.2 mg/g), the test is considered to be valid.

The EC50 (30 -180 min9 of 3,5 -DCP was in the range 2 -25 mg/L

The coefficient of vaiation of the oxygen uptake rate in the control replicates was within 30% at the end of the test.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

key study

Rationale for reliability incl. deficiencies:

other: Based on read-across to source substance. The reliability of the read-across study was assigned a value of 1.

Justification for type of information:

Read-across from study on toxicity to microorganisms one closely structural and physicochemical related substance: 2-Phenoxyethyl acrylate (M140).
For further read-across justification se document attached in section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

177 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Executive summary:

No data is available for 2-Phenoxyethyl methacrylate (T).

Data on toxicity of the functional groups of the source and target substance to microorganism (seen in table 2 of the read-across justification document Section 13) are not mutually comparable (different types of microorganism, effects and test duration), so these data cannot be used to make a clear conclusion regarding methacrylate-based substances’ toxicity to microorganism compared to the corresponding acrylate-based substances’ toxicity to microorganism. However, as the methacrylates are classified as less reactive compared to the acrylates, it justified that data on toxicity to microorganism for the target substance 2-Phenoxyethyl methacrylate can safely – maybe with an overestimation of the toxicity - be achieved by making a read-across to the data for 2-Phenoxyethyl acrylate.

Based on a read-across to the measured toxicity to microorganism of the source substance 2-Phenoxyethyl acrylate,

the toxicity to total respiration of activated sludge organisms (ISO 8192 - corresponding to OECD Guideline no. 209) is found at

-EC20 (30 min) = 57 mg/

-EC50 (30 min) = 241 mg/L;

-EC20 (180 min) = 59 mg/L;

-EC50 (180 min.) = 177 mg/L

See justification for read-across attached in section 13.

Description of key information

The effect of 2-phenoxyethyl acrylate (S) on the total respiration of activated sludge organisms (ISO 8192 (corresponding to OECD Guideline no. 209 apart from a few deviations)) was tested. The effect concentrations obtained in the test were: EC20 (30 min) = 57 mg/L; EC50 (30 min) = 241 mg/L; EC20 (180 min) = 59 mg/L; EC50 (180 min.) = 177 mg/L.

Data on toxicity of the functional groups of the source and target substance to microorganism (seen in table 2 of the read-across justification document Section 13) are not mutually comparable (different types of microorganism, effects and test duration), so these data cannot be used to make a clear conclusion regarding methacrylate-based substances’ toxicity to microorganism compared to the corresponding acrylate-based substances’ toxicity to microorganism. However, as the methacrylates are classified as less reactive compared to the acrylates, it justified that data on toxicity to microorganism for the target substance 2-Phenoxyethyl methacrylate can safely – maybe with an overestimation of the toxicity - be achieved by making a read-across to the data for 2-Phenoxyethyl acrylate.

Based on a read-across to the measured toxicity to microorganism of the source substance 2-Phenoxyethyl acrylate,

the toxicity to total respiration of activated sludge organisms (ISO 8192 - corresponding to OECD Guideline no. 209) is found at

-EC20 (30 min) = 57 mg/

-EC50 (30 min) = 241 mg/L;

-EC20 (180 min) = 59 mg/L;

-EC50 (180 min.) = 177 mg/L

For further read-across justification se document attached in section 13.

Key value for chemical safety assessment

EC50 for microorganisms:

177 mg/L