Tangled Multi-Walled Carbon Nanotubes

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

march 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
no data

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
Range finding test: 1, 35, 50 and 100 mg/L in dilution water
Definitive test: limit test at 100 mg/L

- Sampling method:
For the range finding test:
Suspensions of GRAPHISTRENGTH C100 were directly prepared for each concentration by weighing the convenient amounts of test item into 100 mL of dilution water and adjusting to 5 L in the test tanks.
Final tested concentrations were as follow: 1, 35, 50 and 100 mg/L.

For the definitive test:
The 100 mg/L suspension of GRAPHISTRENGTH C100 was directly prepared by weighing the convenient amount of test item into 100 mL of dilution water and adjusting it to 5 L in the test tanks.

- Sample storage conditions before analysis:
an axial propeller stirring device is used in order to maintain GRAPHISTRENGTH C100 in suspension.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
The stock solution was prepared by dispersing the test item in reconstituted water made up by diluting pure mineral salts (analytical grade) in ultra-pure water according to the composition described in the OECD 203 Guideline. The test solutions were then prepared by diluting the stock solutions in reconstituted water.

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): dilution water

- Evidence of undissolved material (e.g. precipitate, surface film, etc): GRAPHISTRENGTH C100 is known to be insoluble.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM

- Strain:Danio rerio (Teleostei, Cyprinidae).
- Source:Aquatrade France (44150 Ancenis).
- Age at study initiation (mean and range, SD):date of birth stated by the supplier: 29/09/09
- Length at study initiation (length definition, mean, range and SD):(determined by measuring 10 randomly sampled fish), 3.2 ± 0.3 cm.

- Method of breeding:no data
- Feeding during test: no data

ACCLIMATION
- Acclimation period:
The fish were placed under the test conditions (medium, identical or lower biological loading, temperature, lighting, etc.) 20 days before the beginning of the test.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

According to the standard medium:
CaCl2, 2H2O: 11.76 g per litre of water, MERCK Ref. 1.02382.5000 batch A935182902
MgSO4, 7H2O: 4.93 g per litre of water, MERCK Ref. 1.05886.1000 batch A975086904
NaHCO3: 2.59 g per litre of water, MERCK Ref. 1.06329.0500 batch K39347429847
KCl: 0.23 g of per litre of water, MERCK Ref. 1.04936.0250 batch K37429936851

Test temperature:

The temperature, which was measured on a continuous basis in a test flask, was 20.1 ± 1°C.

pH:

pH between 7.46 and 7.87
The pH did not vary by more than 1 unit.
The pH was measured at the beginning and at the end of the test, at the highest concentration and in the control vessel.

Dissolved oxygen:

Dissolved oxygen between 93 and 99 %.
The concentration of dissolved oxygen in the test vessels remained above 60 % of the air saturation value at the end of the test.
The dissolved O2 was measured at the beginning and at the end of the test, at the highest concentration and in the control vessel.

Salinity:

Fresh water test

Nominal and measured concentrations:

nominal concentrations:
1, 35, 50, 100 mg/L for the preliminary test.
100 mg/L for the definitive test (limit test).

Details on test conditions:

TEST SYSTEM
- Test vessel: test tanks with a nominal capacity of 5 litres.
- Material, size, headspace, fill volume:
Physico-chemical parameters were measured using a METTLER TOLEDO 345 pH-meter for measurement of pH and with a WTW OXI 538 oxymeter for dissolved oxygen measurement.
Each tank is equipped with an axial propeller stirring device in order to maintain GRAPHISTRENGTH C100 in suspension. The appearance of the test solutions was visually checked: most of the tiest item particles remains as suspension.
Volume of test medium per tank was 5 L.

- Aeration: no data
- Renewal rate of test solution (frequency/flow rate): no data
- No. of organisms per vessel:
For the preliminary test: 5 fishes/aquarium
For the definitive test: 10 fishes/auarium
- No. of vessels per concentration (replicates):
2 replicates test chambers were maintained in each treatment.
- No. of vessels per control (replicates):
2 replicates test chambers were maintained in control goup.
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Chemical reagents used for the preparation of dilution water are of « analytical grade ».
Dilution water is prepared according to the protocol described in Annex 2 of OECD guideline n°203:

The following stock solutions are prepared:

Dilution water is obtained by adding 25 mL of each of the stock solutions in a final volume of 1 litre and then aerating the solution until oxygen saturation.
Sum of Ca and Mg ions in dilution water is of 2.5 mmol/L and ratios of Ca/Mg et Na/K are 4 and 10 respectively.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 12 hours of darkness per 24 h.
- Light intensity: between 400 and 800 lux at the surface of the aquariums.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no
- Mortality of control: no

Results with reference substance (positive control):

- Results with reference substance valid? yes
- LC50-24h=250 mg/L

Validity criteria fulfilled:

yes

Conclusions:

Validity criteria:
·The mortality in the control did not exceed 10 per cent at the end of the test;
·The concentration of dissolved oxygen in the test vessels remained above 60 % of the air saturation value at the end of the test;

Deviations from the guideline: none
·The pH did not vary by more than 1 unit.

Executive summary:

The determination of the mortality of fish exposed to GRAPHISTRENGTH C100 for a duration of 96 hours was assessed according to the OECD Guideline 203.

Fish were exposed under static conditions to 100 mg/L of GRAPHISTRENGTH C100 dispersed in dilution water (limit test).

The concentrations of test item causing a 50 % mortality at 24-, 48-, 72- and 96-h (LC₅₀) were estimated. The results are as follows:

LC50 -24h, LC50 -48h, LC50 -72h and LC50 -96h determined are > 100 mg/L.

Furthermore, no mortality was observed at any tested concentration. LC0 -96h > 100 mg/L

Description of key information

Acute toxicity to fish of GRAPHISTRENGTH C100 MWCNTs was assessed according to  OECD TG 203. 
Fish were exposed under static conditions to 100 mg/L of GRAPHISTRENGTH C100 dispersed in dilution water (limit test).
No mortality was observed: LC50-96h > 100 mg/L and LC0 -96h > 100 mg/L