Benzyl methacrylate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-01-11 to 2012-02-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

3 October 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material (as cited in study report): Benzyl methacrylate

Analytical monitoring:

yes

Details on sampling:

Benzyl methacrylate was analytically verified by LC-MS/MS in the fresh media (0 h) and old media (48 h) of all tested concentration levels and the control at least once every 7 days. For the old media additionally prepared replicates with test media but without daphnids and algae were prepared and incubated under test conditions until sampling. Additional sampling was done on days 19 and 21 due to the findings in the fresh media of the second sampling interval.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The stock solution (40.0 mg/L test item was weighed out) was freshly prepared with dilution water. The stock solution was treated with ultrasound for 30 min and stirred with approximately 2 hours at room temperature.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Daphnia magna STRAUS (Clone 5)
- Justification for species other than prescribed by test guideline: Daphnia magna is the preferred species in accordance with the test guideline and is bred at the test facility
- Source: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu)
- Age of parental stock (mean and range, SD): 2 to 24 h old daphnids were used for the study. They were obtained by removing the mother animals twice within 22 h.
- Feeding during test
Daily. Per test vessel Pseudokirchneriella subcapitata (0.582 - 1.85 mL) and Desmodesmus subspicatus (0.509 - 0.850 mL) suspension was provided as food corresponding to 0.2 mg Carbon per Daphnia and day. Variation was according to the density of the algae suspension, but was the same for all test groups on each feeding day.

ACCLIMATION
- Acclimation period: At least 2 h in dilution water

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

144 to 174 mg CaCO3/L

Test temperature:

19.0 to 20.8°C

pH:

initial: 7.60 to 7.91 in the geometric mean measured concentration of 26.3 mg/L; 7.83 to 8.40 in control;
final: 7.53 to 7.68 in the geometric mean measured concentration of 26.3 mg/L; 7.52 to 7.89 in control

Dissolved oxygen:

7.75 to 11.34 mg/L

Nominal and measured concentrations:

Nominal: 1.02, 2.56, 6.40, 16.0, 40.0 mg/L.
Measured: 0.291, 0.926, 4.21, 11.7, 26.3 mg/L (corresponding to mean recovery rates of 28 to 73 % of the nominal values)

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (5 (ID) x 8 (H) cm), 100 mL capacity, fill volume 50 mL
- Renewal rate of test solution (frequency/flow rate): Semi-static, medium renewal 3 times per week, i.e. after 48 and 72 h, respectively
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4, modified to a total hardness of 160 to 180 mg CaCO3/L.
- Intervals of water quality measurement: once within 7 days, in fresh and old media, in one replicate of the control and the highest concentration of the test item

OTHER TEST CONDITIONS
- Photoperiod: 16/8 h light/dark cycle
- Light intensity: Max. 20 µE/m²/s
- ‘test temperature: 18 - 22°C, ± 1°C constant

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mortality of parental daphnids (immobile or dying) – daily
Condition of parental daphnids:
Abnormalities (e.g. swimming behaviour, number of males and winter eggs) were observed and recorded at each day of observation.
Total length and dry body weight of parental daphnids:
At the end of the test total length of each daphnid and dry body weight of the daphnids alive at each concentration level and the control was determined.
Number of offspring (alive and dead progeny) - daily
neonates (alive and dead) were removed after counting
dead specimens were removed
number of aborted eggs and dates of observation were recorded.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

4.21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

parents

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

11.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

parents

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

9.97 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

parents

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

15.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

parents

Remarks on result:

other: 95 % confidence limits: 4.21 – 26.3 mg/L

Duration:

21 d

Dose descriptor:

other: EC100

Effect conc.:

26.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks:

parents

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.291 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.926 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

1.03 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95 % confidence limits: < 0.291 – 2.92 mg/L)

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

5.19 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95 % confidence limits: 4.12 – 6.96 mg/L)

Results with reference substance (positive control):

The EC50 of the reference item at 1.69 mg/L (95% confidence limits: 1.64 - 1.73 mg/L) after 24 hours is within the prescribed concentration range of 1.0 - 2.5 mg/L of quality criteria for daphnids clone 5 cultured in Elendt M4 medium. The EC50-value of the reference item is within the recommended range of 0.6 - 2.1 mg/L according to OECD-Guideline 202.

Reported statistics and error estimates:

see section "Any other information on results"

No males and ephippia were observed in either the control or the test groups during the test.

Test Item Related Effects based on the geometric mean measured concentrations of Benzyl methacrylate

Effects	Geometric Mean Measured Concentration of Benzyl methacrylate [mg/L]
	Control	0.291	0.926	4.21	11.7	26.3
Mean Number of Living Juveniles per Producing Parent (Reproduction Rate±SD)	133±13	138±14	102±29^1)	84±44^1)	13±5^1)	---
Coefficient of Variation of the Mean Number of Juveniles per Producing Parent [%]	10	10	29^2)	53^2)	39^2)	---
Percentage of Dead Juveniles Related to the Total Number of Juveniles [%]	0	< 1	2	3	37^1)	---
Mean Intrinsic Rates of Natural Increase	0.49	0.49	0.42^3)	0.37^3)	0.17^3)	---
Appearance of First Brood [Mean Day]	8.2	8.1	9.4^4)	9.9^4)	16.5^4)	---
Mean Number of Broods	4.90	5.00	4.70	3.80^5)	1.88^5)	---
Adult Mortality after 21 Days [%]	10	0	0	0	20	100^6)
Parent Animals: Mean Dry Weight [mg]	0.94	1.01	0.91	0.81	0.34	---
Parent Animals: Mean Body Length [mm]	5.25	5.38	5.18	4.85^3)	3.81^3)	---

SD= Standard deviation

¹⁾   =Statistical significance (One Way Analysis of Variance, Dunnett’s method, p = 0.001)

²⁾   = Significant variation between the test replicates (Coefficient of variation > 25 %)

³⁾   = Statistical significance (Kruskal-Wallis One Way Analysis of Variance on Ranks Dunn’s method, p < 0.05)

⁴⁾   = 1st brood significantly delayed (after day 10) at several daphnids

⁵⁾   = Less than four broods released by several daphnids

⁶⁾   = Significant adult mortality (> 20 %)

 

Validity criteria fulfilled:

yes

Conclusions:

The reduction of the reproductive output was the most sensitive effect in this study.
The No Observed Effect Concentration (NOEC Reproduction) after 21 days was assessed at 0.291 mg/L. The Lowest Observed Effect Concentration (LOEC Reproduction) was assessed at 0.926 mg/L. The EC10-value for the reduction of the reproductive output was calculated by sigmoidal dose-response regression to be 1.03 mg/L (95 % confidence limits: < 0.291 – 2.92 mg/L). The EC50-value for the reduction of the reproductive output was calculated to be 5.19 mg/L (95 % confidence limits: 4.12 – 6.96 mg/L).
The EC10-value for the adult mortality was calculated by sigmoidal dose-response regression to be 9.97 mg/L. The EC50-value was calculated to be 15.3 mg/L (95 % confidence limits: 4.21 – 26.3 mg/L).

Executive summary:

The 21-day-chronic toxicity of BNMA to Daphnia magna Straus was studied under static renewal conditions according to OECD guideline 211 (adopted 3 October 2008). Daphnids were exposed to control and test chemical at measured concentrations of 0.291, 0.926, 4.21, 11.7 and 26.3 mg/L. 

The 21 d EC10 based on mortality was 9.97 mg/L. The 21 day EC50 based on mortality was 15.3 mg/L.

The 21-day NOEC based on reproduction was 0.291 mg/L. The 21 d EC10 based on reproduction was3.34 mg/L (95 % confidence limits: < 0.291 - 2.92 mg/L).The 21 day EC50 based on reproductive effects was 5.19 mg/L. The sublethal effects included were reproduction rate and appearance of first brood. Production of offspring in the treated groups indicated that BNMA had an effect on the reproduction at concentrations greater than 0.291 mg/L. The most sensitive endpoint was the reduction of the reproductive output. 

         .

 

Results Synopsis

 

Test Organism Age (e.g. 1st instar): 2 to 24 h old daphnids

Test Type: Static Renewal

 

NOEL: 0.291 mg/L

EC10: 1.03 mg/L                 95 % confidence limits: < 0.291 - 2.92 mg/L

LOEC: 0.926 mg/L                    Endpoint(s) Effected: reproduction

NOTE: Any of data in this dataset are disseminated by the European Union on a right-to-know basis and this is not a publication in the same sense as a book or an article in a journal. The right of ownership in any part of this information is reserved by the data owner(s). The use of this information for any other, e.g. commercial purpose is strictly reserved to the data owners and those persons or legal entities having paid the respective access fee for the intended purpose.

Description of key information

The 21 d EC10 of BNMA in freshwater invertebrates based on reproduction was 1.03 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.03 mg/L

Additional information

One long-term study in freshwater invertebrates is available for BNMA, which is considered reliable without restriction (Klimisch score 1).

 

The 21-day-chronic toxicity of BNMA to Daphnia magna Straus was studied under static renewal conditions according to OECD guideline 211 (adopted 3 October 2008). Daphnids were exposed to control and test chemical at measured concentrations of 0.291, 0.926, 4.21, 11.7 and 26.3 mg/L. 

The 21 d EC50 based on mortality was 5.19 mg/L.

The 21 d NOEC based on reproduction was 0.291 mg/L. The 21 d EC10 based on reproduction was 1.03 mg/L. The sublethal effects included were reproduction rate and appearance of first brood. Production of offspring in the treated groups indicated that BNMA had an effect on the reproduction at concentrations greater than 0.291 mg/L. The most sensitive endpoint was the reduction of the reproductive output.

The EC10 is used as relevant dose descriptor.