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Long-term toxicity to aquatic invertebrates

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Reference
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2005-02-15 to 2005-03-08
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Guideline study OECD211, GLP. At the limit concentration of 10 µg/l (nominal), corresponding to a time weighted mean measured concentration of 5.73 µg/l, which is above the limit of water solubility (< 1 µg/l), but which had to be used for analytical reasons (because of the LoQ of 1 µg/l), no effects of dodecyl methacrylate on reproduction or immobilisation of the daphnids were found. Valid with restriction: test concentration above the limit of solubility.
Qualifier:
according to
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Version / remarks:
adopted September 1998
Deviations:
no
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 10.0 µg/L
- Sampling method: Samples (10.0 µg/L, control) were stabilised with acetonitrile (1:1) immediately after sampling. 25 mL of new media and 50 mL of old media were used for trace analysis.
- Sample storage conditions before analysis: room temperature, protected from light and moisture
- Expiry date: 2005-03-14
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 10.0 mg test item/L was weighed out onto the cap (with Teflon layer) of a 1 L glass bottle, filled up with 1 L demineralised water and shaken at ca. 20 rpm at room temperature for at least 20 h (rotating shaker 3040, GFL) to get a homogenous emulsion. The renewal frequency of the stock
solution was every 3 to 4 days.
- Controls: 10 replicates without test item tested under the same conditions as the test group
- Chemical name of vehicle: dilution water Elendt M4, according to ELENDT (1990), modified to a total hardness of 160 to 180 mg CaCO3/L.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna STRAUS
- Strain/clone: Clone 5
- Source: Origin: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu); Breeder: Dr. U. Noack-Laboratorien, D-31157 Sarstedt, Germany
- Age of parental stock (mean and range, SD):
- Feeding during test
- Food type: suspension
- Amount: A suspension of Desmodesmus subspicatus (0.385 - 0.670 mL) and Chlorella vulgaris (0.31 0 - 0.825 mL) per test vessel
(corresponding to 0.1 - 0.2 mg C per daphnid and day). It varied according to the growth of the daphnids, but was the same for the control and
test groups on any particular day.
- Frequency: 5 x weekly
Test type:
semi-static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
21 d
Hardness:
Total hardness: > 140 mg/L
Test temperature:
18 - 22 °C ± 2 °C constant
pH:
Initial: 7.93 - 8.14; Final: 7.72 - 8.28 at the limit concentration
Initial: 7.85 - 8.17; Final: 7.73 - 8.33 control
Dissolved oxygen:
Final oxygen concentration: >= 8.30 mg/L (limit concentration and control)
Nominal and measured concentrations:
Limit concentration of nominal 10 µg/L, corresponding to the time weighted mean measured concentration of 5.73 µg/L.
Details on test conditions:
TEST SYSTEM
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16/8 h light/dark cycle
- Light intensity: max. 20 µE * mE-2 * sE-1


EFFECT PARAMETERS MEASURED :
Mortality of parent Daphnia
The number of parent animals which were immobilised or dead during the test and day of death were observed and recorded once a day.
Juveniles
First appearance of juveniles was checked daily. The number of juveniles (alive and dead progeny) was counted and dates of release were recorded
once a day from the first day of production of juveniles until the end of the test. After counting the juveniles were discarded. The number of aborted
eggs and dates of observation were recorded.
Condition of parent Daphnia
Abnormalities (e.g. swimming behaviour, number of males and winter eggs) were observed and recorded each day of observation.
Total length and body weight of parent Daphnia
At the end of the test total length of each daphnid and body weight of the daphnids alive at the limit concentration and control were determined.

VEHICLE CONTROL PERFORMED: yes


RANGE-FINDING STUDY (21 d, non-GLP)
- Test concentrations: 10 µg/L
- Results used to determine the conditions for the definitive study: No effect on reproduction capacity and mortality of the parent animals was
observed.
Based on the results of the preliminary test the definitive study was performed as a limit test with a limit concentration of 10.0 µg/L above the water
solubility level and > LOQ (1 µg/L).
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
>= 5.73 µg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks:
and immobilisation
Remarks on result:
other: test concentration above the water solubility
Details on results:
- Mortality of parent animals: No mortality of parental and control animals during the test period.
- No. of offspring produced per day per female: not applicable, due to production of offspring was done mainly on day 9, 12, 15/16 and 19 of the
test period.
Mean number of offspring alive produced per parent animal after 21 days: 85 ± 4.27 (control group); 82.2 ± 2.30 (test group)
- Body length and weight of parent animals: Total length: 4.50 - 5.00 mm (treated animals); 4.50 - 5.25 mm (control animals)
Dry weight (mean value): 1.15 mg (treated animals; 1.19 (control animals)
No significant effects were determined.
- Type and number of behavioural abnormalities: none (test group and control group)
- Time to first brood release or time to hatch: mean day: 9.0 (control group); 8.8 (test group)
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels:
In order to prove the validity of the test system and test conditions at the testing facility, an acute immobilisation test according to DIN 38412 L11
was carried out with potassium dichromate as reference item once per month. The EC50 of the reference item at 1.84 mg/L (1.74 - 1.95
(95% confidence interval)) after 24 hours was within the validity range of 1.0 to 2.5 mg/L according to DIN 38412 L30.
Reported statistics and error estimates:
The NOEC at the limit concentration for the reproduction was determined directly from the results.
Significant deviations concerning reproduction were determined in comparison to the control group using statistical standard procedures (One Way Analysis of Variance, p < 0.05 for reproduction rate and intrinsic rate of natural increase and KRUSKAL-WALLISS ANOVA on Ranks, p < 0.05 for the
day of release of first brood). Significant deviations concerning the body length were determined in comparison with the control group using
KRUSKAL-WALLISS ANOVA on Ranks, p < 0.05.

Number of Juveniles in the Control and Test Group after 21 Days

TWM

[µg/L]

Number of Juveniles in Replicate No. 1 2 3 4 5 6 7 8 9 10 Total No. No. of Parents alive Mean No. of Juveniles per Parent alive [MV ± SD] CV [%] Comparison versus Control Red.[%] Stat.
 5.73 84 82 82 79 86 80 85 83 81 80  822  10 82.2  ± 2.30  2.80  3.29 no
 Control 85 95 85 83 84 79 83 88 82 86  850   10 85.0  ± 4.27  5.02 --- ---

TWM = Time weighted mean measured concentration

MV ± SD = Mean value ± Standard deviation

CV = Coefficient of variation

Red. = Reduction of reproduction

Stat. = Statistical significance (ANOVA, p < 0.05)

no = Statistically not significant

Summary of all test item related effects on repropduction, NOEC based on time weighted mean measured concentration of 5.73 µg/l

Effect

 

Number of Juveniles (Reproduction Rate)1)

no

Day of Release of 1stBrood1)

no

Stillborn Juveniles and Aborted Eggs

no

Intrinsic Rates (IR)1)

no

Summary of all Test Item Related Effects on Reproduction

no

1)     = Statistical significance (one Way Analysis of Variance, p < 0.05)

No = no significant effect

Validity criteria fulfilled:
yes
Conclusions:
At the limit concentration of nominal 10 µg/L, corresponding to the time weighted mean measured concentration of 5.73 µg/L, above the water
solubility level and > LOQ (< 1 µg/L) no effects of Dodecyl methacrylate on reproduction and immobilisation of daphnids was determined.
Executive summary:

The 21-day-chronic toxicity of Dodecyl methacrylate to Daphnia magna STRAUS (Clone 5) was studied under semi static

conditions according to OECD guideline 211. Daphnids were exposed to Dodecyl methacrylate at limit concentration of 10 µg/L (nominal).

This concentration is higher than the solubility in water (< 1 µg/L) but has, nevertheless, been choosen with regard to the feasibility of

attaining appropriate and analysable test concentrations at 10 µg/L.

10 test organisms, individually held were used for the limit concentration and control. At test start they were 2 to 24 hours old. The test method was semi-static and test solutions were renewed daily.

Concentrations of Dodecyl methacrylate in the stock solution, limit concentration and control of fresh (0 h) and old (24 h) media were determined via HPLC. Samples were taken and analysed on days 0, 7, 16, 20 (fresh media) and on days 1, 8, 17, 21 (old media). The test item concentrations decreased within 24 h. All effect values are given based on the time weighted mean measured concentration for the limit concentration of 5.73 µg/L.

The average number of juveniles per parent in the control group was 85 after 21 days. The reproductive output at the limit concentration was not statistically significant reduced compared to the control (One Way Analysis of Variance, p < 0.05).

The coefficient of variation around the mean number of living offspring produced per parent in the control group was 5.02 % and shows very small variances between the control replicates.

No winter eggs, males, ephippia, stillborn juveniles and aborted eggs occurred in control or test groups.

The mean day of release of first brood was 9 in the control group and the limit concentration. There was no difference between the two groups. At the limit concentration and the control group 4 broods were released during the test period.

The intrinsic rates of natural increase (IR) of the surviving parent animals accounting for generation time and offspring numbers were used for calculation of population growth. The mean IR of the surviving daphnids of the limit concentration was compared to the control by One Way Analysis of Variances (p < 0.05). There was no statistically significant difference. The intrinsic rate was comparable for the control and limit concentration.

The no observed effect concentration (NOEC) after 21 days based on reproduction capacity is the tested limit concentration of 5.73

µg/L. No statistically significant test item related effects were observed at the limit concentration when compared to the control

group. No irnmobilisation of parent animals occurred in the control or test group.

Water quality parameters as pH-value, dissolved oxygen, water hardness and temperature were determined to be within the acceptable limits.

In order to prove the validity of the test system and test conditions at the testing facility, an acute immobilisation test according to DIN 38412 L11 was carried out with potassium dichromate as reference item once per month. The EC50 of the reference item at

1.84 mg/L after 24 hours was within the validity range of 1.0 to 2.5 mg/L according to DIN 38412 L30.

The 21 day LC50/EC50based on reproduction/immobilisation was greater than 5.73 µg/L (mean measured concentration). The 21-day NOEC based on reproduction/immobilisation was 5.73 µg/L (mean measured concentration). Production of offsprings in the treated groups indicated that Dodecyl methacrylate did not have an effect on the reproduction at concentrations greater than 5.73 µg/L.

 

This study is classified as acceptable and satisfies the guideline requirements for a chronic toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age: 2 to 24 hours old at test start

Test Type: Semi-static (renewal daily)

 

NOEL:  5.73 µg/L (based on time weighted mean measured concentration)                 

Endpoint(s) Effected:  reproduction/immobilisation

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

At the limit concentration of nominal 10 µg/l, corresponding to the time weighted mean measured concentration of 5.73 µg/l and

above the water solubility level, no effects of dodecyl methacrylate on reproduction and immobilisation of daphnids were determined in a 21-day-chronic toxicity study with Daphnia magna.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater invertebrates:
5.73 µg/L

Additional information

The 21-day-chronic toxicity of dodecyl methacrylate to Daphnia magna STRAUS was studied under semi static conditions according to OECD guideline 211. Daphnids were exposed to dodecyl methacrylate at a limit concentration of 10 µg/L (nominal).

This concentration is higher than the solubility in water (< 1 µg/L) but has, nevertheless, been chosen with regard to the feasibility of

attaining appropriate and detectable test concentrations at 10 µg/L.

10 test organisms, individually held were used for the limit concentration and control. At test start they were 2 to 24 hours old. The test method was semi-static. Test solutions were renewed daily.

Concentrations of dodecyl methacrylate in the stock solution, limit concentration and control of fresh (0 h) and old (24 h) media were determined via HPLC. Samples were taken and analysed on days 0, 7, 16, 20 (fresh media) and on days 1, 8, 17, 21 (old media). The test item concentrations decreased within 24 h. All effect values were given based on the time weighted mean measured concentration for the limit concentration of 5.73 µg/L.

The average number of juveniles per parent in the control group was 85 after 21 days. The reproductive output at the limit concentration was not statistically significant reduced compared to the control (One Way Analysis of Variance, p < 0.05).

The coefficient of variation around the mean number of living offspring produced per parent in the control group was 5.02 % and shows very small variances between the control replicates.

No winter eggs, males, ephippia, stillborn juveniles and aborted eggs occurred in control or test groups.

The mean day of release of first brood was 9 in the control group and the limit concentration. There was no difference between the two groups. At the limit concentration and the control group 4 broods were released during the test period.

The intrinsic rates of natural increase (IR) of the surviving parent animals accounting for generation time and offspring numbers were used for calculation of population growth. The mean IR of the surviving daphnids of the limit concentration was compared to the control by One Way Analysis of Variances (p < 0.05). There was no statistically significant difference. The intrinsic rate was comparable for the control and limit concentration.

The no observed effect concentration (NOEC) after 21 days based on reproduction capacity is the tested limit concentration of 5.73

µg/L. No statistically significant test item related effects were observed at the limit concentration when compared to the control

group. No immobilisation of parent animals occurred in the control or test group.

Water quality parameters as pH-value, dissolved oxygen, water hardness and temperature were determined to be within the acceptable limits.

In order to prove the validity of the test system and test conditions at the testing facility, an acute immobilisation test according to DIN 38412 L11 was carried out with potassium dichromate as reference item once per month. The EC50 of the reference item at 1.84 mg/L after 24 hours was within the validity range of 1.0 to 2.5 mg/L according to DIN 38412 L30.

The 21 day LC50/EC50based on reproduction/immobilisation was greater than 5.73 µg/L (mean measured concentration).The 21-day NOEC based on reproduction/immobilisation was 5.73µg/L (mean measured concentration). Production of offsprings in the treated groups indicated that Dodecyl methacrylate did not have an effect on the reproduction at concentrations greater than 5.73 µg/L.

 

This study is classified as acceptable and satisfies the guideline requirements for a chronic toxicity study with freshwater invertebrates.

 

Results Synopsis 

Test Organism Age: 2 to 24 hours old at test start

Test Type: Semi-static (renewal daily)

 

NOEC:  5.73 µg/L (based on time weighted mean measured concentration)                 

Endpoint(s) Effected:  reproduction/immobilisation