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EC number: 231-143-9
CAS number: 7440-33-7
The soil moisture and pH were measured in samples collected from the
parent control and treatment soils on day 0. At test termination (study
day 56), the moisture content and soil pH were determined from samples
of test medium collected from a single replicate test chamber (ie
replicate A) for all treatment levels. The soil samples were collected
prior to the enumeration of the juvenile worms. The pH was measured
using a WTW Model pH 330i pH meter. The percent moisture was calculated
as the difference between the wet and dry soil samples and presented as
percent of the soil dry weight using a Mettler Toledo HR73 Halogen
Moisture Analyzer. A continuous temperature record was measured with an
electronic data logger in a chamber containing moistened control soil
and placed in the water bath. Light intensity was measured at test
initiation with a LI-COR Model LI-189 light meter equipped with a
No soil microorganisms toxicity data of sufficient quality are available
for tungsten metal (target substance). However, soil microorganisms
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.
The 56-day NOEC for earthworms (Eisenia fetida) found in a test
conducted according to OECD 222, under GLP standards, and with
analytical verification of the test concentrations was >=1000 mg sodium
tungstate/kg soil dw (586 mg W/kg). Other studies with Eisenia fetida
were not considered for the risk characterisation, as they were found to
be less reliable.
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
approach category in the Category section or Annex 3 in 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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