Reaction mass of ditungsten carbide and tungsten carbide

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP guideline study. Reliability assigned by a secondary source (OECD SIDS Initial Assessment Report). Only secondary source reviewed, as primary study was not available.

Justification for type of information:

1. HYPOTHESIS FOR THE CATEGORY APPROACH: The hypothesis is that properties are likely to be similar or follow a similar pattern because of the presence of a common metal ion, in this case tungstate.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES):
Source: Tungsten Carbide
Target: Fused tungsten carbide
3. CATEGORY APPROACH JUSTIFICATION: See Annex 3 in CSR
4. DATA MATRIX: See Annex 3 in CSR

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Analytical monitoring:

yes

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: STRAUSS
- Source: Federal Health Office, Berlin Germany
- Age at study initiation (mean and range, SD): 2-24 hours.
- Feeding during test: None

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

N/A

Test temperature:

21 +/- 1 ⁰C

pH:

7.5 - 7.9

Dissolved oxygen:

9 mg/L
-The oxygen saturation was >= 60 % (21 ⁰C) at the end of testing.

Nominal and measured concentrations:

32, 58, 100, 180, 320, 580, 1000 mg/L.

Details on test conditions:

TEST SYSTEM:
-Keeping water: M4 medium according to Elendt/Federal Health Office (BGA), Berlin Germany (1992).
-Photoperiod: 10 hours light.
-Illumination: diffuse light, illumination strength 1.5 – 5 umol*m-2*s-1.
-Test vessel: glass beakers, volume 50 mL, 20 mL test medium, not ventilated.
-Number of daphnia per beaker: 5 daphnids.
-Number of replicate: 4 plus 1 control.
-Test parameter: immobilization.

Key result

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

580 mg/L

Key result

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 1 000 mg/L

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Details on results:

The test substance was not soluble in dilution water in a concentration of 1000 mg/l. The test substance was deposited on the ground.

The recovery rates of the active ingredient at the end of the test were > 80 %. For that reason effect level concentrations are given as nominal concentrations.
The percentage of immobility was determined in all concentration groups and controls after 24 and 48 h. Effects - 24h-EC0 = 1000 mg/L
- 48h-EC0 = 580 mg/L
None of the test concentrations resulted in 100 % incapability of swimming during the test period:
- 24h-EC100 = >1000 mg/L
- 48h-EC100 = >1000 mg/L
From the test results a 48h-EC50 of >1000 mg/L was derived.

None of the control daphnids were incapable of swimming at the end of the test or swam on the surface

Reported statistics and error estimates:

no data

Validity criteria fulfilled:

yes

Conclusions:

48 hour EC50 >1000 mg/L

Executive summary:

No aquatic invertebrate short-term toxicity data of sufficient quality are available for fused tungsten carbide (target substance). However, aquatic invertebrate short-term toxicity data are available for tungsten carbide (source substance), which will be used for read-across. Due to similar water solubility and lower toxicity for the target substance compared to the source substance, the resulting read-across from the source substance to the target substance is appropriate. In addition, read-across is appropriate because the classification and labelling is similar for the source substance than the target substance, the PBT/vPvB profile is the same, and the dose descriptors are, or are expected to be, lower for the source substance. For more details, refer to the read-across category approach included in the Category section of this IUCLID submission and/or as an Annex in the CSR.

Description of key information

Fused tungsten carbide was not tested for short-term toxicity to aquatic invertebrates and read-across to tungsten carbide was used for this endpoint. The test substance was not soluble in dilution water in a concentration of 1000 mg/l. The percentage of immobility was determined in all concentration groups and controls after 24 and 48 h. Effects are not regarded as significant for the EC0 values. EC0 values were determined directly from the test results. From the test results a 48h-EC50 of >1000 mg/L was derived. None of the control daphnids were incapable of swimming at the end of the test or swam on the surface.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1 000 mg/L

Additional information

No aquatic invertebrate short-term toxicity data of sufficient quality are available for fused tungsten carbide (target substance). However, aquatic invertebrate short-term toxicity data are available for tungsten carbide (source substance), which will be used for read-across. Due to similar water solubility and lower toxicity for the target substance compared to the source substance, the resulting read-across from the source substance to the target substance is appropriate. In addition, read-across is appropriate because the classification and labelling is similar for the source substance than the target substance, the PBT/vPvB profile is the same, and the dose descriptors are, or are expected to be, lower for the source substance. For more details, refer to the read-across category approach included in the Category section of this IUCLID submission and/or as an Annex in the CSR