Registration Dossier

Ecotoxicological information

Short-term toxicity to fish

Currently viewing:

Administrative data

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From March 01, 2001 to March 05, 2001
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report date:
2001

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
yes
Remarks:
tests conducted in sealed vessels
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
4-methylstyrene
EC Number:
210-762-8
EC Name:
4-methylstyrene
Cas Number:
622-97-9
Molecular formula:
C9H10
IUPAC Name:
1-methyl-4-vinylbenzene
Test material form:
liquid
Details on test material:
- Prd no.: 684-146831

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Although the test substance is stable in water, it is volatile, therefore both the range finding and definitive study were conducted in sealed vessels. The study design used was static renewal with a proposed water change at 48 hours. Test solutions were sampled at the start and end of each water change.

Test solutions

Vehicle:
no
Details on test solutions:
Suitable stock solutions were prepared undiluted directly into testing water.

Test organisms

Test organisms (species):
Pimephales promelas
Details on test organisms:
TEST ORGANISM
- Common name: Fathead minnow
- Source: Aquatic Biosystems, Colorado
- Age at study initiation: juvenile fish weighing 3.6 mg (10 fish therefore give a biological loading of 0.018 g/L in study aquaria)
- Feeding during test: no

ACCLIMATION
- Acclimation period: fourteen days
- Acclimation conditions: virtually the same as in the test (temperature 22°C)
- Type and amount of food: Artemia salina
- Feeding frequency: once per day
- Health during acclimation: 0% mortality and good health

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h

Test conditions

Hardness:
40 - 48 mg/L calcium carbonate. In the definitive study the hardness of water reduced by 4.0 mg/Lof calcium carbonate between changes
Test temperature:
22 +/- 1°C
pH:
6.7 - 7.5 (measured)
Dissolved oxygen:
6.8-9.0 mg/L (minimum saturation level 78%)
Nominal and measured concentrations:
Nominal concentrations
Range finding study as listed above.
Definitive study: 0 (untreated control), 1.6, 2.5, 4.0, 6.4 & 10 mg/L. Mean measured concentrations: 0 (untreated control), 0.82, 1.3, 2.6, 4.2 & 6.8 mg/L.
Details on test conditions:
TEST SYSTEM
The test was performed under static, renewal conditions in sealed ½ gallon vessels that contained approximately 2 L of the test solution in order to minimum head space and the losses of the test substance.

- Test vessel: 3.8 L
- Renewal rate of test solution: 48-hours
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: average fish weight: 3.6 mg/L
- Source/preparation of dilution water: local supply, carbon filtered and deionized. Water was adjusted to hardness 40 to 48 mg/L as CaCO3 and stored in polyethylene tanks were it was aerated and recirculated through particle filters, activated carbon and an ultraviolet sterilizer.
- Photoperiod: 16 hours light
- Light intensity: 83 foot candles
- Dissolved oxygen: minimum noted 78 % saturation
- Effects monitored: mortality and toxic effects

TEST CONCENTRATIONS
- Spacing factor for test concentrations: as the protocol
- Range finding study
- Test concentrations: untreated control, 0.1, 1.0, 5.0, 10.0 and 100 mg/L
- Results used to determine the conditions for the definitive study: Yes
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
5.2 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
mortality (fish)
Key result
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
2.6 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr.
Basis for effect:
mortality (fish)
Details on results:
- Behavioral abnormalities: at concentrations above 4.2 mg/L affected fish were either intermittently or completely mobilised/lost equilibrium or were lethargic.
- Observations on body length and weight: none recorded.
- Other biological observations: none other than those recorded above.
- Mortality of control: no mortality.
- Effect concentrations exceeding solubility of substance in test medium: not applicable test concentrations were within the solubility range of test material.
- Nominal concentrations: the results are recorded as nominal concentrations however due to volatility of the test substance losses were experienced during the preparation of test solutions and transfer of test solutions to test vessels. Results of analysis showed that during preparation nominal concentrations of 5.0 mg/L reduced to 3.7-4.3 mg/L but there was no loss between water changes (analysed concentrations range from 103 – 125 % of the initial measured concentration).
Reported statistics and error estimates:
Standard statistical techniques used as recommended in the guideline. LC50 calculated using the probit method (Stephan et al 1978).

Any other information on results incl. tables

Sublethal observations / clinical signs:

Information on the nominal and measured concentration in the definitive study is shown in table below.

Nominal conc mg/L

Measured concentration mg/L

% of nominal

0 hrs

48 hrs(a)

48 hrs(b)

96 hrs

Mean

0

ND

ND

ND

ND

ND

-

1.6

0.73

0.91

0.76

0.89

0.82

51

2.5

1.2

1.2

1.2

1.5

1.3

52

4.0

2.5

2.5

2.7

2.6

2.6

65

6.4

4.1

4.3

3.8

4.6

4.2

66

10.0

7.1

6.2

6.5

7.3

6.8

68

The results of assessments of toxicity in the definitive study are shown in the table below.

Measured conc mg/L

% mortality

0 hrs

24 hrs

48 hrs

72 hrs

96 hrs

Replicate

1

2

1

2

1

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0.82

0

0

0

0

0

0

0

0

0

0

1.3

0

0

0

0

0

0

0

0

0

0

2.6

0

0

0

0

0

0

0

0

0

0

4.2

0

0

0

0

20

0

20

0

30

10

6.8

0

0

10

0

10

0

70

40

80

90

The results of effects assessments are shown in the table below.

Measured conc mg/L

% showing effects

0 hrs

24 hrs

48 hrs

72 hrs

96 hrs

Replicate

1

2

1

2

1

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0.82

0

0

0

0

0

0

0

0

0

0

1.3

0

0

0

0

0

0

0

0

0

0

2.6

0

0

0

0

0

0

0

0

0

0

4.2

0

0

0

30

50

100

80

90

100

100

6.8

0

50

80

80

100

100

30

60

100

100

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the study conditions, the 96 h mean measured LC50 was 5.2 mg/L (confidence intervals: 4.6 to 5.9 mg/L) and the 96 h NOEC was 2.6 mg/L.
Executive summary:

A study was conducted to determine the toxicity of the test substance to Fathead minnow (Pimephales promelas) according to OECD Guideline 203, in compliance with GLP. The study was carried out in sealed test vessels due to the volatility of the substance. Groups of 10 fish were exposed to nominal concentrations of 0, 1.6, 2.5, 4.0, 6.4 and 10 mg/L for 96 h under semi-static conditions (48 h renewal). Larger than recommended aquaria were used to ensure that oxygen concentrations in the test media were adequate for fish survival between renewal dates. Analytical dose verification showed that measured concentrations were equivalent to 0, 0.82, 1.3, 2.6, 4.2 and 6.8 mg/L. Losses of the test substance occurred during mixing and loading of the aquaria. However, the test substance was stable in water between changes. Final measured concentrations were 103 and 125% of initial levels, indicating that once the aqueous solutions of the test substance were sealed into the test vessels, concentrations remained constant. Oxygen concentrations were adequate for fish survival (no mortalities in the untreated control). Under the study conditions, the 96 h mean measured LC50 was 5.2 mg/L (confidence intervals: 4.6 to 5.9 mg/L) and the 96 h NOEC was 2.6 mg/L (Wyskiel, 2000).