Tungsten hexachloride

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

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.

Reference 2

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.