methyl acrylate; methyl propenoate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 Mar 1995 - 25 Mar 1995 (experimental)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Water samples were collected from each replicate test chamber approximately 24 hours before the test (pre-test) to determine if the test concentrations in the diluter had reached equilibrium. Water samples were collected again at test initiation, on Day I and at test termination.
- Sample storage conditions before analysis: The samples were collected in glass scintillation vials and stored at approximately 4°C until analyzed.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A separate stock solution was prepared for each test concentration.

FLOW-THROUGH SYSTEM
- Apparatus: A continuous-flow diluter was used to deliver each concentration of the test substance and a negative (well water) control. A peristaltic pump (Cole-Parmer Instrument Company) was used to deliver the five test substance stock solutions into mixing chambers assigned to each treatment. The stock solutions were diluted with well water in the mixing chambers in order to obtain the desired test concentrations. The flow of dilution water to the mixing chambers was controlled by rotameters. Rotameters were calibrated prior to test initiation. The flow of test water from each mixing chamber was split and allowed to flow into two replicate test chambers. The proportion of test water that was split into each replicate was checked prior to the test to ensure that flow rates varied by no more than ±10 % of the mean for the two replicates. All surfaces that came in contact with the test substance were constructed of Teflon@, glass, stainless steel, or silicone.
- Flow-through rate: The diluter was adjusted so that each test chamber received approximately 14 volume additions of test water every 24 hours.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Obtained from cultures maintainted by Wildlife International Ltd.
- Age at study initiation (mean and range, SD): < 24 h
- Feeding during test: none


ACCLIMATION
- Acclimation period:0 day holding period
- Acclimation conditions (same as test or not): same temperature
- Type and amount of food: Cerophyll (R) and trout chow, as well as a suspension of green alga, Selenastrum capricornutum
- Health during acclimation (any mortality observed): no mortality observed

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

none

Test temperature:

20 +/- 2 °C

pH:

8.4

Dissolved oxygen:

> 60 % of saturation

Nominal and measured concentrations:

Nominal test concentrations (mg/L): 1.3, 2.2, 3.6, 6.0, 10
Measured concentration (mg/L): 0.88, 1.7, 2.5, 4.1, 6.4

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 ml glass beakers (8 cm diameter, 13 cm height)
- Fill volume: 6.5 l
- Type of flow-through (e.g. peristaltic or proportional diluter): continuous flow diluter
- Renewal rate of test solution (frequency/flow rate): 14 volume additions per 24 h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: freshwater obtained from a well 45 meters deep located on the Wildlife International Ltd. site. The water was filtered and aerated.


OTHER TEST CONDITIONS
- Photoperiod:16:8 h day-night regime
- Light intensity:194 -215 LUX at a wavelength comparable to natural sunlight.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mobility after 17, 24 and 48 hours

Reference substance (positive control):

not specified

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

0.88 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % LCL: 2.4 - 3.0 mg/L

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

6.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.88 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

other: EC50, 24 hrs

Effect conc.:

> 6.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities:
Several daphnids were observed as floating during the test. However, these "floaters" appeared normal after they were resubmerged with a drop of water. The occurrence of "floaters" did not appear to be treatment related. Daphnids in the negative control and 0.88 mg methyl acrylate/L treatment appeared healthy and normal throughout the test. After 48 hours of exposure, mortality/immobility values in the 1.7, 2.5, 4.1 and 6.4 mg methyl acrylate/L treatment groups were 5 %, 35 %, 100 % and 100 %, respectively.
At 24 hours, 4/20 daphnids at the highest test concentration appeared lethargic. At 48 hours 2/20 and 2/20 daphnids were described as lethargic at the measured test concentrations of 1.7 and 2.5 mg/L, respectively.

- Mortality of control: no
- Other adverse effects control: no

Reported statistics and error estimates:

Probit analysis

Percent immobilization:

Mean meas. conc. [mg/L]	17 h	24 h	48 h
Control	0	0	0
0.88	0	0	0
1.7	0	0	5
2.5	0	0	35
4.1	0	10	100
6.4	0	15	100

Nominal concentrations selected for use in this study were 1.3, 2.2, 3.6, 6.0 and 10 mg/L. Measured concentrations of methyl acrylate in the pre-test (Day -1) samples ranged from 65 to 77 % of nominal. Samples collected at test initiation were 61 to 83 % of nominal and samples collected at test termination were 63 to 77 % of nominal. When measured concentrations at test initiation and termination were averaged, the mean measured concentrations were 0.88, 1.7, 2.5, 4.1 and 6.4 mg methyl acrylate/L.

The 48-hour EC50 value for daphnids exposed to methyl acrylate was 2.6 mg methyl acrylate/L. The 95% confidence limits were 2.4 and 3.0 mg methyl acrylate/L, and the slope of the concentration-response curve was 10.6. The NOEC and no mortality/immobility concentration, determined by examination of the mortality/immobility and observation data, was 0.88 mg methyl acrylate/L.

Validity criteria fulfilled:

yes

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Dec 1995 - 21 May 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-guideline study.

Qualifier:

according to guideline

Guideline:

EPA OTS 797.1930 (Mysid Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
Water samples were collected from each test chamber approximately 24 hours before the test (pretest), at the beginning of the test, at approximately 48 hours of the test and at the end of the test to determine concentrations of the test substance. If 100 % mortality was observed in any treatment, then sampling of that treatment was terminated following the next sampling interval.

- Sampling method: Samples were collected in glass scintillation vials.

- Sample storage conditions before analysis: Samples were analyzed immediately or stored under refrigeration until analyzed.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Stock solutions were prepared separately for each test concentration.

Test organisms (species):

Americamysis bahia (previous name: Mysidopsis bahia)

Details on test organisms:

TEST ORGANISM
- Common name: saltwater mysid
- Source: juveniles were obtained from cultures maintained by Wildlife International Ltd., Easton, Maryland.
- Feeding during test
- Food type: live brine shrimp (Artemia sp.) nauplii
- Frequency: daily

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

no

Test temperature:

25 (±2) °C

pH:

8.2 - 8.3

Dissolved oxygen:

> 60 % saturation

Salinity:

20 (±1) ‰

Nominal and measured concentrations:

Nominal test concentrations (mg/L): 1.2, 1.9, 3.2, 5.4 and 9.0
Measured concentration (mg/L): 0.40, 0.66, 0.99, 1.7 and 3.1

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 300mL glass beakers with nylon screen-coverd holes were suspended in 8L stainless steel test chambers filled with approx. 6.5L test water.
- Type of flow-through (e.g. peristaltic or proportional diluter): peristaltic pump (Cole-Parmer Instrument Company)
- Renewal rate of test solution (frequency/flow rate): approx. 14 volumes of testwater every 24 h.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: filtered natural seawater collected at Indian River Inlet, Delaware, and diluted to a salinity of approx. 20‰ with well water.
- Total organic carbon: 1.4 mg/L


OTHER TEST CONDITIONS
- Photoperiod: 16 h of light and 8 h of darkness. 30min transition period of low light to avoid sudden changes in lighting.
- Light intensity: 284 - 292 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Mobility/mortality after 24, 48, 72 and 96 hours
- Temperature, dissolved oxygen, pH and salinity were measured in each test concentration at test inition, after 48 hours and test termination.

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.99 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CL: 0.99 - 3.1 mg/L

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

0.99 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Reported statistics and error estimates:

In this study, the binomial method was used to evaluate mortality at 48, 72, and 96 hours. The no mortality concentration and NOEC were determined by inspection of the mortality and clinical observation data.

Nominal concentrations selected for use in this study were 1.2, 1.9, 3.2, 5.4 and 9.0 mg methyl acrylate/L. Samples collected at the beginning of the test had measured values that ranged from 40 to 47 % of nominal values. Measured values for samples taken at 48 and 96 hours ranged from 25 to 33 % and 22 to 30 % of nominal values, respectively. When measured concentrations of samples collected at test initiation, 48 hours, and test termination were averaged, the mean measured concentrations for the study were 0.40, 0.66, 0.99, 1.7 and 3.1 mg methyl acrylate/L. Mean measured concentrations were used in the estimation or calculation of LC50 values.

Mysids in the negative control, 0.40 and 0.99 mg methyl acrylate/L treatment groups appeared healthy and normal throughout the test. After 96 hours of exposure, mortality in the 0.66, 1.7 and 3.1 mg methyl acrylate/L was 5, 55 and 100 %, respectively. The 96-hour LC50 value for saltwater mysids exposed to methyl acrylate was 1.6 mg methyl acrylate/L. The 95 % confidence limits were 0.99 and 3.1 mg methyl acrylate/L. Although 5 % mortality occurred in the 0.66 mg methyl acrylate/L treatment group, no mortality or adverse effects were observed in the 0.99 mg methyl acrylate/L treatment group. Consequently, the no mortality concentration and NOEC were considered to be 0.99 mg methyl acrylate/L.

Cummulative mortality and treatment related effects:

Measured Conc. [mg/l]	19 h		24 h		48 h		72 h		96 h
	No. dead	Effects	No. dead	Effects	No. dead	Effects	No. dead	Effects	No. dead	Effects
NC	0	20 AN	0	20 AN	0	20 AN	0	20 AN	0	20 AN
0.40	0	20 AN	0	20 AN	0	20 AN	0	20 AN	0	20 AN
0.66	0	20 AN	0	20 AN	0	20 AN	0	20 AN	0	20 AN
0.99	0	20 AN	0	20 AN	0	20 AN	0	20 AN	0	20 AN
1.7	0	20 AN	0	20 AN	3	12AN, 2C, 3E	10	6AN, 3E	10	6AN, 3E
3.1	0	19 AN, 1C,E	2	2AN, 16C,E	20	-	20	-	20	-

AN = appears normal; C = lethargic; E = erratic swimming

Validity criteria fulfilled:

yes

Description of key information

Methyl acrylate is acutely toxic to freshwater and saltwater invertebrates.
EC50 (48 h) = 2.6 mg/L (measured), (Daphnia magna, OECD TG 202, flow through)
LC50 (96 h) = 1.6 mg/L (measured), (Mysidopsis bahia, EPA OTS 797.1930, flow through)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

2.6 mg/L

Marine water invertebrates

Marine water invertebrates

Dose descriptor:

LC50

Effect concentration:

1.6 mg/L

Additional information

An acute toxicity study with Daphnia magna (BAMM, 1995) indicated the 48-hour EC50 was 2.6 mg/L based on mean measured concentrations. This study followed OECD TG 202, part I using a flow-through design. Nominal exposure concentrations ranged from 1.3 to 10 mg/L and mean measured concentrations ranged from 0.88 to 6.4 mg/L. Complete immobilization occurred in the two highest concentrations (4.1 and 6.4 mg/L, measured). The NOEC was 0.88 mg/L (measured).

In a second toxicity study with the seawater invertebrate Mysidopsis bahia (BAMM, 1996) an 96-hr LC50 of 1.6 mg/L based on mean measured concentrations was determined. This study was conducted according to the procedures in Title 40 of the Code of Federal Regulations, Part 797, Section 1930, Mysid Shrimp Acute Toxicity Test, using a flow-through design. Nominal exposure concentrations ranged from 1.2 to 9 mg/L and mean measured concentrations ranged from 0.4 to 3.1/L. After 96 hours of exposure, mortality in the 0.66, 1.7 and 3.1 mg methyl acrylate/L was 5, 55 and 100 %, respectively. Mysids in the negative control, 0.40 and 0.99 mg methyl acrylate/L treatment groups appeared healthy and normal throughout the test. Thus, the NOEC was considered to be 0.99 mg/L (measured).

In a short-term test with Daphnia magna conducted according to EEC guideline a 48-hour EC50 of 2.21 mg/L was found (BASF AG, 1989). The given effect value was related to nominal concentrations.

Since MA is readily biodegradable and undergoes slow hydrolysis in water, only test results from studies with analytical monitoring were used for the hazard assessment for freshwater and saltwater invertebrates.

In addition, a robust data set of acute studies is available from the other members of the acrylic ester category (2-ethylhexyl, ethyl, n-butyl, isobutyl, and tert-butyl acrylate).