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Short-term toxicity to aquatic invertebrates

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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:
read-across: supporting information
Qualifier:
according to
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.
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
580 mg/L
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
> 1 000 mg/L
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

48 hour EC50 >1000 mg/L

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
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