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EC number: 231-143-9
CAS number: 7440-33-7
Reported statistics and error estimates (Cont'd):
Estimates of the EC50 concentration values and their 95% confidence
limits for immobilization data 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.
No aquatic invertebrates chronic toxicity data of sufficient quality are
available for tungsten metal (target substance). However, aquatic
invertebrates chronic toxicity data are available for sodium tungstate
(source substance), which are used for read across. Due to lower 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 as a conservative estimate of
potential toxicity for this endpoint. In addition, read-across is
appropriate because the PBT/vPvB profile is the same, and the dose
descriptors are, or are expected to be, higher for the source substance.
For more details, refer to the read-across category approach in the
Category section of this IUCLID submission or Annex 3 in the CSR.
Tungsten metal was not tested for chronic toxicity to invertebrates, and
read-across to sodium tungstate was used for this endpoint. In a
reproduction test using Daphnia magna and testing sodium tungstate, the
21-day NOEC for reproduction and growth was found to be 44.2 mg/L sodium
tungstate/L or approximately 26 mg W/L).
Due to lower transformation/dissolution results for tungsten metal (the
target substance) than sodium tungstate (the source substance), the
resulting toxicity potential would also be expected to be lower, so
read-across is appropriate. In addition, read-across is justified
because the classification and labelling is the less severe for the
target substance and the PBT/vPvB profile is the same. Finally, the dose
descriptor for the target substance is expected to be sufficiently
higher than the source chemical, and read-across to the source chemical
is adequately protective. For more details, refer to the read-across
category approach in the Category section or Annex 3 of the CSR.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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