2-hydroxyethyl acrylate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

GLP-guideline study performed by japanese authorities, no study report available for review.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material (as cited in report): 2-hydroxylethyl acrylate
- Analytical purity: no data

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

6 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): 2-hydroxethyl acrylate (HEA)
- Analytical purity: 99.23%

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

24 ± 2 °C

pH:

7.49 - 8.48 in the control replicates

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 0.625, 1.25, 2.5, 5.0 and 10.0 mg/L
- Measured concentrations: not determined

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterile erlenmeyer flasks, volume 250 mL
- Type: covered with cotton wool plugs
- Fill volume: 100 mL
- Initial cells density: 1E+04 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- Others: Test containers were placed on a rotary shaker and oscillated at approximately 100 rpm.

GROWTH MEDIUM
- Standard medium used: yes; threefold concentrated medium according to OECD guideline (AAP medium).
- Intervals of water quality measurements: The pH-value at the beginning of the test was measured out of one additional replicate of each concentration and control. At the end it was measured from a pool of all replicates. The water temperature was recorded hourly during the test. The room temperature was measured continuously by a hygrothermograph. Light intensity was measured prior to test start.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: 24 h/d light
- Light intensity and quality: 66.5 µE/m² (±10%)
- Light regime: 24 h/d light

EFFECT PARAMETERS MEASURED
Cell density was measured via Chlorophyll-a-fluorescence, exitation at 435 nm, emission at 685 nm. Each replicate was measured 6-fold. The cell density was measured at the beginning of the test and every 24 h. Filtrated culture medium was used as ground signal. Microscopic evaluation of the cells at the start and at the end of the incubation was determined. Also any unusual cell shapes, colour differences, differences in chloroplast morphology, flocculations, adherence of algae to test containers or aggregation of alga cell were observed.
- Other: Recovery of algae: After 96 h 5 mL alga suspension from the nominal concentration 10 mg/L and from the control were transferred to 100 mL untreated test medium and allowed to grow for further 3 - 4 d to determine whether the effect of the test item was reversible. The test medium and growing conditions were the same as used in the main test.

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 10, 100 and 1000 mg/L
- Results used to determine the conditions for the definitive study :For the preliminary test, inhibition based on biomass was 98, 100 and 100% of control at 10, 100 and 1000 mg/L, respectively. Corresponding inhibition based on growth rate was 72, 100 and 100%.

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

8.81 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% C.I. = 7.98 - 9.72 mg/L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.96 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% C.I. = 3.53 - 4.44 mg/L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.625 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

Microscopic evaluation of the cells at the end of the incubation period revealed no morphological abnormalities. Growth rate inhibition was observed from 2.5 mg/L (2.62%) and increased up to 11.1% and 68% at 5.0 and 10.0 mg/L, respectively. See 'Any other information on results incl. tables'.

Table: Summary of cell density, area under growth curves and growth rate for the definitive test:

Nominal conc. (mg/L)	Average Cell Counts (x10000)				Inhibition of biomass %	Growth Rate-related Inhibition %
	24 h	48 h	72 h	96 h	-	-
0	8.3	46	201	453	-	-
0.625	7.6	48	202	389	6.1	1.9
1.25	7.2	43	170	395	13.4	1.5
2.5	7.3	29	138	362	27	2.62
5.0	5.6	19	111	252	46	11.1
10.0	4.2	5.5	7.5	6.4	96	68

ADDITIONAL EFFECT VALUES

Inhibition of Biomass (area under the curve):

EbC50 (96h) = 4.12 mg/L (95% CI = 3.75 - 4.52 mg/L)

LOEC (72h) = 1.25 mg/L

NOEC (96h) = 0.625 mg/L

LOEC (96h) = 1.25 mg/L

Inhibition of Growth:

ErC50 (96h) = 8.26 mg/L (95% CI = 7.62 - 8.95 mg/L)

LOEC (72h) = 2.5 mg/L

NOEC (96h) = 2.5 mg/L

LOEC (96h) = 5.0 mg/L

 

Validity criteria fulfilled:

yes

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

supporting study

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

6.98 mg/L

Basis for effect:

growth rate

Remarks on result:

other: test result from read-across source CAS 25584-83-2 (HEA/HPA Consortium, 2005).

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.625 mg/L

Basis for effect:

growth rate

Remarks on result:

other: test result from read-across source CAS 25584-83-2 (HEA/HPA Consortium, 2005).

Description of key information

ErC50 = 6 mg/L mg/L (Pseudokirchnerella subcapitata)

NOErC = 1 mg/L (Pseudokirchnerella subcapitata)

Key value for chemical safety assessment

EC50 for freshwater algae:

6 mg/L

EC10 or NOEC for freshwater algae:

1 mg/L

Additional information

Two studies are available that assessed the toxicity of 2-hydroxyethyl acrylate to freshwater algae. Further, data of a close structural analogue (CAS 25584-83-2) is available and used as supporting information.

The acute toxicity of 2-hydroxyethyl acrylate to aquatic algae was investigated according to OECD Guideline 201. After 72 hours of exposure to Pseudokirchnerella subcapitata an ErC50 of 6 mg/L was measured using the growth rate as endpoint (MOE, 1998). Although no detailed test report is available, all tests from the Japanese Authorities are performed according to OECD guidelines and GLP. Also, data on a second study is available, the 72-h EC50 and NOEC values were determined to be 8.81 mg/L and 1.25 mg/L, respectively (HEA/HPAConsortium, 2004)

In the study with the structural analogue 2 -hydroxypropyl acrylate an ErC50 (72h) of 6.98 mg/L based on growth was determined.

Overall, the lowest determined effect values of 6 mg/L (ErC50) and 1 mg/L (NOErC) (MOE, 1998) will be used as key value for the chemical safety assessment for freshwater algae.