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Adsorption / desorption

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Endpoint:
adsorption / desorption: screening
Type of information:
calculation (if not (Q)SAR)
Remarks:
Scientifically acceptable calculation method
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
no guideline followed
Principles of method if other than guideline:
Calculation method determining the Koc for charged molecules.

GLP compliance:
no
Type of method:
other: calculation of log Koc for ionized molecule
Media:
soil/sewage sludge
Type:
Koc
Value:
31 L/kg
Type:
log Koc
Value:
1.49 L/kg

The data refer to the charged molecule.

Validity criteria fulfilled:
not applicable
Conclusions:
The Koc and Log Koc of formic acid were calculated to be 31 and 1.49 respectively.
Executive summary:

Based on a Log Pow value of -0.46 and a pKa value of 3.70, the Koc and Log Koc of formic acid were reliably calculated to be 31 and 1.49, respectively (Franco and Trapp, 2008; BASF SE, 2009).

Endpoint:
adsorption / desorption, other
Type of information:
(Q)SAR
Adequacy of study:
other information
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Generally scientifically accepted method, but EPI Suite not validated for inorganic salts
Principles of method if other than guideline:
PCKOC (v1.66)
Type of method:
other: calculated
Media:
soil
Test temperature:
25 °C
Type:
Koc
Value:
1 L/kg
Remarks on result:
other: PCKOC (v1.66) QSAR calculation based on MCI Method

Koc may be sensitive to pH.

Validity criteria fulfilled:
not applicable
Conclusions:
A Koc value of 1.00 L/Kg was estimated for sodium formate by the PCKOC (v1.66) QSAR in the EPISuite (v3.12) software based on the MCI Method.
Executive summary:

A Koc value of 1.00 L/Kg was estimated for sodium formate by the PCKOC (v1.66) QSAR in the EPISuite (v3.12) software based on the MCI Method. However, this Koc value is not assignable since EPISuite is not validated for inorganic salts.

Endpoint:
adsorption / desorption: screening
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance has a low octanol water partition coefficient and the adsorption potential of this substance is related to this parameter
the study does not need to be conducted because the substance and its relevant degradation products decompose rapidly
Justification for type of information:
In accordance with column 2 of REACH Annex VIII, the study does not need to be conducted since sodium formate is readily biodegradable (KM Lab, 1998) and has a low potential for adsorption due to high water solubility coupled with a very low octanol-water partition coefficient (log Kow <-1.8, Perstorp, 2009).
Reason / purpose for cross-reference:
data waiving: supporting information
Reason / purpose for cross-reference:
data waiving: supporting information
Endpoint:
adsorption / desorption: screening
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
It is considered appropriate to address the adsorption/desorption data requirement for potassium formate by read-across to an available reliable calculation on formic acid.
Sodium formate is the sodium salt of formic acid, and will dissociate immediately in aqueous and biological surroundings to the formate ion. It is therefore expected that the environmental profile of formic acid and sodium formate will be similar.
Reason / purpose for cross-reference:
read-across: supporting information
Specific details on test material used for the study:
Formic acid is being used as a read-across for sodium formate.
Type:
Koc
Value:
31 L/kg
Type:
log Koc
Value:
1.49 L/kg

The data refer to the charged molecule.

Validity criteria fulfilled:
not applicable
Conclusions:
The Koc and Log Koc of formic acid were calculated to be 31 and 1.49 respectively, and are considered suitable for read-across to sodium formate.
Executive summary:

It is considered appropriate to address the adsorption/desorption data requirement for sodium formate by read-across to an available reliable calculation on formic acid. Sodium formate is the sodium salt of formic acid, and will dissociate immediately in aqueous and biological surroundings to the formate ion. It is therefore expected that the environmental profile of formic acid and sodium formate will be similar.

 

Based on a Log Pow value of -0.46 and a pKa value of 3.70, the Koc and Log Koc of formic acid were reliably calculated to be 31 and 1.49, respectively (Franco and Trapp, 2008; BASF SE, 2009). These values are therefore also considered for sodium formate.

Description of key information

In accordance with column 2 of REACH Annex VIII, the study does not need to be conducted since sodium formate is readily biodegradable (KM Lab, 1998) and has a low potential for adsorption due to high water solubility coupled with a very low octanol-water partition coefficient (log Kow = -0.47; US EPA, 2006). Adsorption to the solid soil phase is therefore not expected.

Key value for chemical safety assessment

Additional information

A read across was performed to formic acid in order to have a reliable value for the calculation of PNECsed and PNECsoil via the equilibrium partitioning method.

The Koc and log Koc of the dissociated, charged form at realistic environmental pH values was calculated by using the pKa (= 3.70) and the logPow of the uncharged molecule (= -0.46) for a corrected logKoc according to Franco et al. (2008). For the formate ion which will be present at environmental relevant pH values, slightly higher adsorption rates were estimated (Koc = 31, log Koc = 1.49) (BASF SE, 2009).