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Short-term toxicity to fish

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Endpoint:
short-term toxicity to fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
This information is used in a read-across approach in the assessment of the target substance.

Reason / purpose for cross-reference:
read-across source
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 200 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Remarks on result:
other: No mortality in any control or test solution
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 181 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Remarks:
based on mean calculated concentrations of sodium tungstate
Basis for effect:
mortality (fish)
Remarks on result:
other: No mortality in any control or test solution
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
200 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
behaviour
Remarks on result:
other: Lack of mortality and sublethal effects
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 181 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Remarks:
based on mean calculated concentrations of sodium tungstate
Basis for effect:
behaviour
Remarks on result:
other: Lack of mortality and sublethal effects
Details on results:
Biological Results:
After 96 hours of exposure, there was no mortality in the control or any of the test substance treatments. There were no sublethal observations during the exposure. The estimated 24-, 48-, 72-, and 96-hour LC50 values for zebrafish exposed to sodium tungstate dihydrate were >200 mg/L, the highest concentration tested. Since there was no partial response, the 96-hour slope of the concentration-response line could not be calculated from the probit analysis. The 96 hour o Observed Effect Concentration (NOEC) was 200 mg/L based on the lack of mortality and sublethal effects at this and lower test substance concentrations.
Reported statistics and error estimates:
Both the LC50 and the NOEC was determined based on the absence of any mortality or sublethal effects.
Validity criteria fulfilled:
yes
Conclusions:
Based on nominal concentrations, the estimated 96-hour LC50 value for zebrafish exposed to sodium tungstate dihydrate was > 200 mg/L, the highest concentration tested. Accordingly, derivation of a concentration-response relationship is not appropriate. The 96-hour NOEC was 200 mg/L, based on the lack of mortality and sublethal effects at this and the lower concentrations.
Executive summary:

In a 96-h acute toxicity study, zebrafish (Danio rerio) were exposed to sodium tungstate dihydrate at nominal concentrations of 0 (control), 13, 25, 50, 100, and 200 mg a.i./L and mean calculated concentrations of < LOQ (Control), 12.0, 23.1, 46.1, 89.2, and 181 mg a.i./L (89–92 % of nominal) under static conditions.  The 96-hour LC50 was > 181 mg a.i./L. The NOEC value, based on mortality and sublethal effects, was 181 mg a.i./L, respectively.  No sublethal effects were observed. 

 

This toxicity study is classified as acceptable and satisfies the guideline requirement for acute toxicity study to fish.

 

Results Synopsis

 

Test organism: D. rerio (30 (± SD 1.2) mm (controls only); mean 0.276 ± 0.0664 g (controls only))

 

Test Type: Static

 

LC50:  > 181 mg a.i./L                        

NOEC:  181 mg a.i./L                          

Endpoint(s) Effected: mortality, sublethal effects (swimming behaviour)

This information is used in a read-across approach in the assessment of the target substance.

For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Endpoint:
short-term toxicity to fish
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
This information is used in a read-across approach in the assessment of the target substance.
Reason / purpose for cross-reference:
read-across source
Duration:
48 h
Dose descriptor:
LC0
Effect conc.:
>= 5.25 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
WO3
Basis for effect:
mortality (fish)
Duration:
48 h
Dose descriptor:
LC0
Effect conc.:
>= 4.16 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Remarks:
Tungsten (W)
Basis for effect:
mortality (fish)
Duration:
72 h
Dose descriptor:
LC0
Effect conc.:
>= 5.26 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
WO3
Basis for effect:
mortality (fish)
Duration:
72 h
Dose descriptor:
LC0
Effect conc.:
>= 4.18 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Remarks:
Tungsten (W)
Basis for effect:
mortality (fish)
Duration:
96 h
Dose descriptor:
LC0
Effect conc.:
>= 5.25 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Remarks:
WO3
Basis for effect:
mortality (fish)
Duration:
96 h
Dose descriptor:
LC0
Effect conc.:
>= 4.16 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Remarks:
Tungsten (W)
Basis for effect:
mortality (fish)
Details on results:
All results are expressed in terms of mean measured concentrations. Measured concentrations correspond to 212 % of nominal values of tungsten trioxide at 0 hours, to 208 % of nominal values of tungsten trioxide at 24 hours, to 212 % of nominal values of tungsten trioxide at 48 hours, to 212 % of tungsten trioxide at 72 hours, and to 208 % of nominal values of tungsten trioxide at 96 hours, respectively.
Results with reference substance (positive control):
n/a
Reported statistics and error estimates:
no data
Validity criteria fulfilled:
yes
Conclusions:
Highest test concentration resulting in 0 % mortality (LC0, 96h) ≥ 5.25 mg/L test substance.
Executive summary:

In a 96-h acute toxicity study, zebrafish (Danio rerio) were exposed to tungsten trioxide at the saturation limit, i.e. measured 5.2-5.3 mg/L (WO3), rsp. 4.15-4.20 mg/L (W) under static conditions.  The 96-h LC50 was > 4.16 mg W/L (corresponding to 5.25 mg WO3/L; measured concentrations). The NOEC value, based on mortality and sublethal effectsis 4.16 mg W/L (5.25 mg WO3/L).  No sublethal effects were observed. 

This toxicity study is classified as supplementary and satisfies the guideline requirement for the zebrafish acute toxicity study.

 

Results Synopsis

 

Test organism: D. rerio (mean 3.5 cm, S.D. = 0.33 cm)

Test Type: Static, Limit test

 

96-hour LC50 > 4.16 mg W/L (corresponding to 5.25 mg WO3/L; measured concentrations).

Endpoint(s) Effected: mortality and abnormal effects

This information is used in a read-across approach in the assessment of the target substance.

For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Description of key information

Tungsten hexachloride was not tested for short-term toxicity to fish, and read-across to tungsten trioxide and sodium tungstate dihydrate was used for this endpoint.

No deaths or sublethal effects were observed at the single test concentration of 5.2 -5.3 mg WO3/L in an acute toxicity test with tungsten trioxide; a definitive LC50could not be determined.

In a 96-h static test according to OECD 203 with sodium tungstate dihydrate the LC50 observed in Danio rerio was found to be above the highest concentration tested (>181 mg sodium tungstate/L or approximately 106 mg W/L).

This information is used in a read-across approach in the assessment of the target substance.

For details and justification of read-across please refer to the attached report in section 13 of IUCLID.

Recalculation of this values to the corresponding concentrations of tungsten hexachloride result in a theoretic value of LC50 > 229 mg WCl6/L

However, this value considerably exceeds the water solubility of the substance which is in the range of 20 - 42.1 µg/L (pH 2-3) and 44.8 µg/L after adjustment to pH 7 (Golz, 2017). Therefore, no adverse effects in fish are expected through the amount of soluble tungsten ions released from tungsten hexachloride in water.

Key value for chemical safety assessment

Additional information