Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 231-135-5 | CAS number: 7440-25-7
Adsorption / desorption
Administrative data
Link to relevant study record(s)
- Endpoint:
- adsorption / desorption: screening
- Type of information:
- other: handbook
- Adequacy of study:
- supporting study
- Study period:
- not reported
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- other: Handbook data for which assurances of quality, such as peer review processes are not reported.
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Data presented as a short abstract in a handbook.
- GLP compliance:
- not specified
- Radiolabelling:
- not specified
- Type:
- Kd
- Remarks:
- All soils (L/kg)
- Value:
- 780
- Remarks on result:
- other: Minimum 2.4E2 Maximum 3.0E3 s.d. 2.7 compendium of 5 values
- Type:
- Kd
- Remarks:
- Mineral (L/kg)
- Value:
- 560
- Remarks on result:
- other: Minimum 2.4E2 Maximum 1.3E3 s.d. 2.1 compendium of 4 values
- Type:
- Kd
- Remarks:
- Organic (L/kg)
- Value:
- 3 000
- Remarks on result:
- other: Only one value available
- Validity criteria fulfilled:
- not applicable
- Conclusions:
- The water-soil equilibrium distribution coefficient of tantalum was reported to be:
Kd All soils 7.8E2 (Minimum 2.4E2 Maximum 3.0E3 s.d. 2.7 compendium of 5 values)
Kd Mineral 5.6E2 (Minimum 2.4E2 Maximum 1.3E3 s.d. 2.1 compendium of 4 values)
Kd Organic 3.0E3 - Executive summary:
The water-soil equilibrium distribution coefficient of tantalum was reported to be:
Kd All soils 7.8E2 (Minimum 2.4E2 Maximum 3.0E3 s.d. 2.7 compendium of 5 values)
Kd Mineral 5.6E2 (Minimum 2.4E2 Maximum 1.3E3 s.d. 2.1 compendium of 4 values)
Kd Organic 3.0E3
- Endpoint:
- adsorption / desorption: screening
- Data waiving:
- study technically not feasible
- Justification for data waiving:
- other:
Referenceopen allclose all
Data presented as a short abstract, no further information available.
Description of key information
In accordance with section 2 of REACH Annex XI, further information on adsorption/desorption, listed under standard information requirement 9.3.3 of Annex IX of the same regulation, does not need to be conducted as a study is technically not feasible to conduct. As tantalum is highly insoluble in water, analytical measurements cannot be performed with sufficient accuracy. Additionally, as tantalum metal is an inorganic substance, biodegradation testing is per se not feasible.
Handbook data from the IAEA indicate the following values for Ta:
Kd (All soils) = 7.8E2 L/kg (Minimum 2.4E2 Maximum 3.0E3 s.d. 2.7 compendium of 5 values);
Kd (Mineral) = 5.6E2 L/kg (Minimum 2.4E2 Maximum 1.3E3 s.d. 2.1 compendium of 4 values);
Kd (Organic) = 3.0E3 L/kg, No guideline reported; Kd value from TRS-364.
A mean value, Kd 720 mL/g was carried forward for risk assessment purposes, this is equivalent to a Koc of 36000 based on 2 % OC.
Key value for chemical safety assessment
- Koc at 20 °C:
- 36 000
Other adsorption coefficients
- Type:
- log Kp (solids-water in soil)
- Value in L/kg:
- 720
- at the temperature of:
- 20 °C
Other adsorption coefficients
- Type:
- log Kp (solids-water in sediment)
- Value in L/kg:
- 1 800
- at the temperature of:
- 20 °C
Other adsorption coefficients
- Type:
- log Kp (solids-water in suspended matter)
- Value in L/kg:
- 3 600
- at the temperature of:
- 20 °C
Other adsorption coefficients
- Type:
- log Kp (solids-water in raw sewage sludge)
- Value in L/kg:
- 10 800
- at the temperature of:
- 20 °C
Other adsorption coefficients
- Type:
- log Kp (solids-water in settled sewage sludge)
- Value in L/kg:
- 10 800
- at the temperature of:
- 20 °C
Other adsorption coefficients
- Type:
- log Kp (solids-water in activated sewage sludge)
- Value in L/kg:
- 13 300
- at the temperature of:
- 20 °C
Other adsorption coefficients
- Type:
- log Kp (solids-water in effluent sewage sludge)
- Value in L/kg:
- 13 300
- at the temperature of:
- 20 °C
Other adsorption coefficients
- Type:
- log Kp (soil-water)
- Value in L/kg:
- 1 080
- at the temperature of:
- 20 °C
Additional information
In accordance with section 2 of REACH Annex XI, the adsorption/desorption screening study does not need to be conducted as the study is technically not feasible to conduct. Due the insolubility of tantalum in water, analytical measurements cannot be performed with sufficient accuracy.
Other adsorption coefficient indicated
as dimensionless:
- log Kp (suspended matter-water) ,901.0 at the temperature 20.0°C
- log Kp (sediment-water) ,901.0 at the temperature 20.0°C
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.
