Tungsten hexachloride

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

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:

24 h

Dose descriptor:

EC50

Effect conc.:

> 163 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks:

sodium tungstate

Basis for effect:

other: immobilization

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 163 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks:

sodium tungstate

Basis for effect:

other: immobilization

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

90.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks:

sodium tungstate

Basis for effect:

other: immobilization

Details on results:

After 48 hours of exposure, immobility was 0, 0, 0, 0, 5 and 15 % in the control and 11.9, 21.5, 41.5, 90.8, and 163 mg/L treatments, respectively. There were no sublethal effects noted in any of the control or test substance treatments. Based on mean measured concentrations, the 48 hour EC50 was > 163 mg/L, the highest concentration tested. Immobility was significantly increased at only the highest test concentration level. The 48 hour NO Observed Effect Concentration (NOEC) was determined to be 90.8 mg/L, based on the lack of statistically significant (p=0.05) immobility and sublethal effects at this test substance treatment.

Results with reference substance (positive control):

n/a

Reported statistics and error estimates:

All statistical analyses were performed with SAS software. Estimates of LC50 values and their 95 % confidence limits were calculated using the probit method and trimmed Spearman-Karber method. When the p value for goodness of fit was > 0.05 and there was no other evidence of questionable convergence, the probit method was selected for reporting. When this criterion was not achieved, the trimmed Spearman-Karber method was selected for reporting. The NOEC was determined by using a one-tailed Dunnett’s test.

Validity criteria fulfilled:

not specified

Conclusions:

The 48 hour EC50 value was estimated to be >163 mg/L. The 48 hour NOEC was 90.8 mg/L based on the lack of statistically significant (p=0.05) immobility and sublethal effects at this and lower test substance treatments.

Executive summary:

The 48 h acute toxicity of tungsten trioxide to Daphnia magna was studied under static conditions. Daphnids were exposed to control, and test chemical at mean measured concentrations of sodium tungstate dihydrate of 0 (control), 11.9, 21.5, 41.5, 90.8, and 163 mg/L. Mortality and immobilization were observed daily. The 48–hour EC₅₀was > 163 mg sodium tungstate dihydrate/L. The 48-hour NOEC based on immobilization was 90.8 mg Na₂WO₄/L (56.8 mg W/L).

 

This study is classified as supplementary and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age: 1^stinstar

Test Type: Static

 

EC₅₀:  > 163 mg Na₂WO₄/L (102 mg W/L)

NOEC (immobility): 90.8 mg Na₂WO₄/L (56.8 mg W/L)

Endpoint(s) Effected: mortality, immobility

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 aquatic invertebrates

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:

EC0

Effect conc.:

>= 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WO3

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 3.3 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks:

WO3

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 2.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: W

Basis for effect:

mortality

Details on results:

The results are expressed in terms of mean measured concentrations (at 48 h). Measured concentrations correspond to 66 % of nominal (tungsten trioxide - WO3) at 0 hours and at 48 hours.

Results with reference substance (positive control):

n/a

Reported statistics and error estimates:

no data

Validity criteria fulfilled:

not specified

Conclusions:

48 hour EC0 ≥ 2.6 mg/L (W); ≥ 3.3 mg/L (WO3)

Executive summary:

The 48-h acute toxicity of tungsten trioxide to Daphnia magna was studied under static conditions.  Daphnids were exposed to control, and test chemical at nominal concentration of 5 mg a.i./L and measured concentration of 3.3 mg WO₃/L for 48 h (according to 2.6 mg W/L).  Mortality and immobilization were observed daily.  The 48-h LC₅₀was > 2.6 mg W/L.  The 48-h NOEC based on mortality and immobilization was 2.6 mg W/L. Investigations on the following sublethal effects were included in the study design: alteration of the normal mobility behaviour and the loss of locomotory actions. 

 

This study is classified as supplementary and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age (e.g. 1^stinstar): 1^stinstar

Test Type (Flowthrough, Static, Static Renewal): Static, Limit test

 

EC₅₀:  > 2.6 mg W/L (meas.)

NOEC:  ≥ 2.6 mg W/L (meas.)

Endpoint(s) Effected: mortality, alteration of the normal mobility behaviour and the loss of locomotory actions

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

The acute toxicity to aquatic invertebrates was tested using sodium tungstate dihydrate and tungsten trioxide.

Tungsten trioxide was applied at a single nominal concentration of 5 mg/L, corresponding to a measured concentration of 2.6 mg W/L. No immobilisation was observed; therefore, a definitive EC₅₀ could not be determined.

In the test on Daphnia employing sodium tungstate dihydrate as test substance the EC₅₀ was found to be above the highest concentration tested (> 163 mg Na₂WO₄/L, corresponding to 102 mg W/L).The 48-hour NOEC based on immobilization was 90.8 mg Na₂WO₄/L (56.8 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 these values to corresponding concentrations of tungsten hexachloride result in theoretic values of:

- NOEC = 122.5 mg WCl₆/L

- EC₅₀ > 220 mg WCl₆/L

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