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EC number: 215-231-4
CAS number: 1314-35-8
Adsorption data for tungsten metal and sodium tungstate are presented in
this section. The soluble species released are expected to be similar
for each of the compounds and are thus expected to behave similarly in
the environment. However, the amount of soluble species resulting from
tungsten metal and sodium tungstate is different, with sodium tungstate
being much more soluble. Therefore, data for sodium tungstate and
tungsten metal are expected to adequately capture the range of mobility
of tungsten trioxide in the environment.
The adsorption/desorption is highly dependent on the characteristics of
the soil system in question. For example, soil sorption coefficients of
tungsten metal and sodium tungstate are found to increase with
decreasing pH (Bednar et al, 2008). Additionally, soil-tungsten systems
may take up to approximately 3-4 months to reach equilibrium (Griggs et
al, 2009 and Bednar et al, 2008). Soil sorption coefficients measured
for sodium tungstate ranged from 16.6 to 863 L/kg (Bednar et al, 2008
and Griggs et al, 2009).
Other partitioning coefficients for tungsten in the environment were
estimated using paired sampling data. Tungsten partition coefficients
for water-sediment were derived using paired environmental monitoring
samples of tungsten in water and sediment collected in various parts of
the EU, resulting in a median calculated Kd of 140000 (Salminen (Ed.) et
The following partitioning coefficients were statistically derived
based on studies using appropriate methodology:
Kd soils (Griggs et al, 2009 and Bednar et al, 2008):
Kd sediment (Salminen (ed.) et al, 2005):
No data on volatilisation are available for tungsten trioxide.
Volatilization is not expected to be a significant pathway for tungsten
metal, based on the low vapor pressure and ionic or insoluble state of
tungsten in the environment. However, most tungsten compounds are
expected to exist as ions or insoluble solids in the environment.
Therefore, volatilization from moist soil and water surfaces is not
expected to be an important fate process (HSDB, 2008). Tungsten is also
not expected to volatilise from dry soil surfaces based upon its ionic
character and extremely low vapor pressure at environmentally relevant
temperatures (1 x 10-10 Pa at 1700°C (Lassner et al, 2005) and 8.15 x
10-8 Pa at 2000°C (Lassner and Schubert, 1999).
No data on the behavior of tungsten trioxide in the environment are
available. Overall, data for sodium tungstate and tungsten metal are
expected to adequately capture the range of mobility of tungsten
trioxide. For more details, refer to the read-across category approach
description in the Category section of this IUCLID submission 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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