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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: RM W2C + WC
3. CATEGORY APPROACH JUSTIFICATION: See Annex 1 in CSR
4. DATA MATRIX: See Annex 1 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 degrees C.
pH:
7.5 - 7.9
Dissolved oxygen:
9 mg/L
-The oxygen saturation was >= 60 % (21 degrees C) 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 the RM of W2C and WC (target substance). However, aquatic invertebrate short-term toxicity data are available for tungsten carbide (source substance), which will be used for reading 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 the RM of W2C and WC (target substance). However, aquatic invertebrate short-term toxicity data are available for tungsten carbide (source substance), which will be used for reading 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