2-hydroxyethyl acrylate

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: ASTM´s "Microbiological Inhibtion Testing Procedure"

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): 2-hydroxethyl acrylate
- Physical state: liquid
- Analytical purity: 97%
- Storage condition of test material: cool, dark

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Test substance: A stock solution of the test substance was prepared at 1000 mg active/L in deionized (DI) water. An aliquot of the stock solution was submitted for total organic carbon (TOC) analysis. The result was 0.553 mg C/mg active.
- Reference substance: A stock solution was prepared in DI water at a concentration of 300 mg active/L. An aliquot was submitted for TOC analysis. The result was 0.4 mg C/mg active.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Source: Downington Regional Water Pollution Control Center in Downington, Pennsylvania
- Preparation of inoculum for exposure: The total suspended solids was determined to be 3247 mg/L. Sludge was added to to semi-continuous activated sludge and diluted with tap water to obtain a concentration of 2500 mg/L. Sludge was aerated overnight prior test. 40 mL of this sludge was diluted 1:10 with BOD dilution water. The diluted sludge was used as the microbial inoculum.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

20 ± 0.2 °C

Dissolved oxygen:

ca. 9 mg/L at test initiation

Nominal and measured concentrations:

- Nominal test concentrations: 0 (control), 0.1, 1.0, 5.0, 10, 15, 20, 100, 300, 500 and 800 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 mL glass bottles
- Fill volume: 100 mL test solution
- Aeration: yes
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: BOD dilution water; 1 liter of ASTM Type II (deionized) water contains 1 mL of following standard reagent solutions: magnesium sulfate solution, 2.25%; calcium chloride solution, 2.75%; phosphate buffer, pH 7.2; ferric chloride solution, 0.025%

Reference substance (positive control):

yes

Remarks:

D-glucose (6 mg/L)

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Test results for dilution water and D-glucose controls:

Dilution water controls			D-glucose controls
Bottle no.	Initial DO (mg O2/L)	Final DO (mg O2/L)	Bottle no.	Initial DO (mg O2/L)	Final DO (mg O2/L)
46	9.0	9.0	55	9.1	5.6
58	9.2	9.1	209	9.1	5.6

Description of key information

The 72-h EC10 value is >100 mg/L as observed in a Microbiological Inhibition Test.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

The toxicity of 2-hydroxyethyl acrylate to microorganisms of a domestic sewage treatment plant was investigated according to ASTM´s "Microbiological Inhibition Testing Procedure" (Roy F. Weston, Inc., 1996). Activated sludge was incubated with nominal test substance concentrations of 0 (control), 0.1, 1.0, 5.0, 10, 15, 20, 100, 300, 500 and 800 mg/L. After 72 hours of exposure an EC10 > 100 mg/L was determined measuring the respiration rate.