Silicon dioxide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Pimephales promelas

Test type:

static

pH:

control: 7.3 (t0), 7.5 (t96h)
0.5 mg/L: 7.3 (t0), 7.6 (t96h)
1.0 mg/L: 7.3 (t0), 7.6 (t96h)
50 mg/L: 7.4 (t0), 7.6 (t96h)
500 mg/L: 7.7 (t0), 7.7 (t96h)
5000 mg/L: 8.8 (t0), 8.0(t96h)

Dissolved oxygen:

[mg/L]
control: 8.5 (t0), 8.0 (t96h)
0.5 mg/L: 8.5 (t0), 8.2 (t96h)
1.0 mg/L: 8.5 (t0), 7.8 (t96h)
50 mg/L: 8.5 (t0), 7.9 (t96h)
500 mg/L: 8.5 (t0), 8.1 (t96h)
5000 mg/L: 8.5 (t0), 7.1 (t96h)

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

other: LC20

Effect conc.:

5 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 20% mortality

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 5 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Based on visual observation, the water control solution and the test solutions were clear with no color throughout the test. Mortalities were 0,0,0,0, 0 and 20% in the 0, 0.5, 1.0, 50, 500 and 5000 mg/L test concentratins, respectively. All water parameters were within acceptable limits.

Validity criteria fulfilled:

not applicable

Conclusions:

Colloidal silica (40% SiO2 in water) exhibited very low toxicity in a 96-hour, unaerated, static acute test using fathead minnow, Pimephales promelas

Executive summary:

A range-finding study was performed to provide an estimate of aquatic toxicity using fixed test concentrations (i.e. 0, 0.5, 1.0, 50, 500, 5000 mg/L). Based on visual inspection, all test solutions were clear with no color throughout the test. Mortalities were 0, 0, 0, 0, 0 and 20% in the 0, 0.5, 1.0, 50, 500 and 5000 mg/L test concentratins, respectively. All water parameters were within acceptable limits.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 Dec. 1991 - 13 Dec. 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: stirring for 20 h, then allowed to stand for 4 h before testing;
- Eluate: no, suspensions were tested
- Differential loading: yes, 1000 + 10,000 mg/L
- Controls: Synthetic medium from groundwater
- Evidence of undissolved material (e.g. precipitate, surface film, etc): The test solutions remained turbid throughout the test, and starchy particles were observed on the bottom of the test vessels.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebra fish
- Strain: --
- Source: M.B. Ruysbroek B.V./Noordvliet 159, Maassluis
- Age at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD): 2.1 +-0.1 cm
- Weight at study initiation (mean and range, SD): 0.07 +-0.01 g
- Food during test: no

ACCLIMATION
- Acclimation period: no data
- Type and amount of food: no data

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

none

Hardness:

204 mg/L as CaCO3

Test temperature:

24.2 - 25.3

pH:

7.3 - 8.3

Dissolved oxygen:

7.3 - 8.5 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

1000 and 10,000 mg/L SiO2 nominal (loading)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass beaker, 2 L, 1500 ml test suspension
- Aeration: slight aeration (no data)
- Type of flow-through (e.g. peristaltic or proportional diluter): --
- Renewal rate of test solution (frequency/flow rate): no
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): --
- Biomass loading rate: approx. 0.5 g fish/L


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: prepared from groundwater by addition of several salts
- Total organic carbon: 1.7 mg/L
- Alkalinity: -- no data
- Ca/Mg ratio: 1.83
- Conductivity: --


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light, 8 h dark
- Light intensity: -- no data


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): survival. swimming behaviour, colour, respiratory function,
morphologial and physiological changes that were visually observable at 24, 48, 72, and 96 h


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Justification for using less concentrations than requested by guideline: limit test, expected low toxicity
- Range finding study
- Test concentrations: --
- Results used to determine the conditions for the definitive study: --

Key result

Duration:

96 h

Dose descriptor:

LL0

Effect conc.:

10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

mortality (fish)

Remarks:

: 0/20 animals died

Remarks on result:

other: suspension

Details on results:

- Behavioural abnormalities: none
- Observations on body length and weight: none
- Other biological observations: no particular findings
- Mortality of control: none
- Other adverse effects control: none
- Abnormal responses: none

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

not applicable

Sublethal observations / clinical signs:

After 96 h of exposure all animals were alive and their conditions (swimming behaviour, colour, respiratory function or any other visually observable morphological or bahavioural criterion) was equal to that of the control animals.

Validity criteria fulfilled:

yes

Conclusions:

The substance was not acutely toxic to Danio rerio at loadings of 1,000 and 10,000 mg/L.

Executive summary:

A GLP study was performed in accordance with OECD 203. Test solutions were prepared by stirring an excess amount (i.e. 1000 and 10,000 mg/L nominal loading) for 20 h and then were allowed to stand for 4 h before testing. The resulting suspension was used for testing. After 96 h of exposure all animals were alive and their conditions (swimming behaviour, colour, respiratory function and any other visually observable morphological or bahavioural criterion) was equal to that of the control animals. The test item was not acutely toxic to Danio rerio at loadings of 1000 and 10,000 mg/L.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 Nov. 1991 - 23 Nov. 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: stirring for 20 h, then allowed to stand  for 4 h before testing;
- Eluate: no, suspensions were tested
- Differential loading: yes, 1000 + 10,000 mg/L
- Controls: Synthetic medium from groundwater
- Evidence of undissolved material (e.g. precipitate, surface film, etc): The resulting suspensions at the beginning of the test were homogeneous and milky, at the end of the test in addition a layer of white, starchy flocks on the bottom of the vessels was observed.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebra fish
- Strain:
- Source: M.B. Ruysbroek B.V./Noordvliet 159, Maassluis
- Age at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD): 2.2 +-0.2 cm
- Weight at study initiation (mean and range, SD): 0.09 +-0.02 g
- Method of breeding:
- Feeding during test: no


ACCLIMATION
- Acclimation period: no data
- Type and amount of food: no data
- Feeding frequency: no data

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

none

Hardness:

204 mg/L as CaCO3

Test temperature:

24.5 - 25.3 °C

pH:

7.3 - 8.2

Dissolved oxygen:

7.1 - 8.2 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

1000 and 10,000 mg SiO2/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass beaker, 2 L, 1000 ml test suspension
- Aeration: slight aeration (no data)
- Type of flow-through (e.g. peristaltic or proportional diluter): --
- Renewal rate of test solution (frequency/flow rate): no
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): --
- Biomass loading rate: approx. 0.9 g fish/L


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: prepared from groundwater by addition of several salts
- Total organic carbon: 1.7 mg/L
- Alkalinity: -- no data
- Ca/Mg ratio: 1.83
- Conductivity: --



OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light, 8 h dark
- Light intensity: -- no data


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): survival. swimming behaviour, colour, respiratory function,
morphological and physiological changes that were visually observable at 24, 48, 72, and 96 h


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Justification for using less concentrations than requested by guideline: limit test, expected low toxicity
- Range finding study
- Test concentrations: --
- Results used to determine the conditions for the definitive study: --

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LL0

Effect conc.:

10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

mortality (fish)

Remarks:

: 0/20 animals died

Remarks on result:

other: suspension

Details on results:

- Behavioural abnormalities: none
- Observations on body length and weight: none
- Other biological observations: no particular findings
- Mortality of control: none
- Other adverse effects control: none
- Abnormal responses: none

Results with reference substance (positive control):

not appliicable

Reported statistics and error estimates:

not applicable

Validity criteria fulfilled:

yes

Conclusions:

The substance was not acutely toxic to Brachydanio rerio at at loadings of 1000 and 10,000 mg/L.

Executive summary:

A GLP study was performed in accordance with OECD 203. Test solutions were prepared by stirring an excess amount (1000 and 10,000 mg/L nominal loading) for 20 h and then were allowed to stand for 4 h before testing. The resulting suspension was used for testing. After 96 h of exposure all animals were alive and their conditions (swimming behaviour, colour, respiratory function and any other visually observable morphological or bahavioural criterion) was equal to that of the control animals. The test item was not acutely toxic to

Brachydanio rerio at loadings of 1000 and 10,000 mg/L.

Description of key information

For the assessment of the aquatic toxicity of synthetic amorphous silica (SAS) to fish, the database compiles 3 studies from 1992 and 1998. All these studies were conducted according to OECD TG 203 under GLP. The acute toxicity of SAS was determined in two studies with Brachydanio rerio. Suspensions were prepared by stirring an excessive concentration (i.e. 1000 or 10,000 mg/L nominal loading) for 20 h; the resulting suspension was tested. No effects were observed at 10,000 mg/L. The 96h NOEC of colloidal non surface treated SAS for Pimephales promelas was determined at 500 mg/L, with 20% mortality observed at 5000 mg/L.

Additional information

LC50 value was not determined in all studies within the range of test concentrations of which the highest concentration was much greater than the concentration limit of 100 mg/L recommended in the current OECD TG 203.