1-(N,N-bis(2-ethylhexyl)aminomethyl)-1,2,4-triazole

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption, other

Remarks:

other: calculation of log Koc for ionized molecule

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Principles of method if other than guideline:

Calculation method determining the Koc for charged molecules based on a calculated log Pow (EPISUITE v4.1, uncharged molecule) and an estimated pKa (25°C, SPARC v4.6)

GLP compliance:

no

Type:

Koc

Value:

43 261 L/kg

pH:

5

Temp.:

20 °C

Type:

log Koc

Value:

4.64 dimensionless

pH:

5

Type:

Koc

Value:

43 254 L/kg

pH:

7

Temp.:

20

Key result

Type:

log Koc

Value:

4.64 dimensionless

pH:

7

Type:

Koc

Value:

43 185 L/kg

pH:

8

Temp.:

20 °C

Type:

log Koc

Value:

4.64 dimensionless

pH:

8

The data refer to the charged molecule.

Conclusions:

Regarding the charged molecule, at pH 7 the log Koc was estimated to be 4.64 (Koc = 43254 L/kg) following the method of Franco & Trapp (2008, 2009, 2010) and using the pKa of 10.59 and the estimated log Kow for the uncharged molecule of 6.56. The correction was performed for pH 5, 7, and 8, which represents 98% of the European soils.

Due to the uncertainty of the measured value according to OECD 121, the calculated value for pH 7 using the method of Franco & Trapp (2008, 2009, 2010) will be used as key value, i.e. for PEC and PNEC calculations.

Description of key information

Guideline study to GLP is available on the test substance. However, this study was performed with water and the the substance is known to hydrolyse in contact with water immediately. Hydrolysis was not considered in the test design or interpretation of the results.

The results are therefore not used for further assessment and are disregarded and the hydrolysis products are considered.

Adsorption of the major hydrolysis product bis(2-ethylhexyl)amine to solid phase is expected. The other degradation products are expected to be of higher mobility in soil.

Due to the uncertainty and method deficiencies of the measured value on the actual substance according to OECD 121, the calculated value for pH 7 using the method of Franco & Trapp (2008, 2009, 2010) will be used as key value, i.e. for PEC and PNEC calculations.

Key value for chemical safety assessment

Koc at 20 °C:

43 254

Additional information

Hydrolysis products:

bis(2 -ethylhexyl)amine

The adsorption coefficient was measured according to the HPLC method (OECD 121). At pH 9.0, the HPLC retention time of the substance was greater than those of the reference substances. Therefore, the log Koc was determined as > 5.63. At pH 7.0, a log Koc of 5.5 was determined for the charged molecule (BASF SE, 2013, study no. 11L00538).

In addition, the Koc was estimated using both models of KOCWIN v2.00 of EPI Suite v4.10 (BASF SE, 2013). Using the Molecular Connectivity Index (MCI) which is regarded as more reliable compared to the log Kow method, the log Koc for the uncharged molecule was estimated to be 4.49 (Koc = 30880 L/kg). Based on the measured log Pow of 7.3 (25 °C, pH 7.5; OXEA 2010, report no. AN-ASB 0496), the log Koc was estimated at 4.92 (Koc = 83060 L/kg) using the log Kow method. Both estimates refer to the uncharged molecule (pKa 10.59).

The pKa of 10.6 indicates that the molecule will exist primarily as a cation in the environment and cations generally adsorb stronger to soils containing organic carbon and clay than their neutral counterparts. Hence, the KOCWIN model may underestimate adsorption to organic carbon since it does not consider the ionic structure of the molecule. Under environmental conditions (pH from 5 to 8) the test substance is almost completely present in its charged form (as calculated by the formula% ionised = 100/(1+10(pKa - pH)): 100% at pH 5 to 8).

Regarding the charged molecule, at pH 7 the log Koc was estimated to be 4.64 (Koc = 43254 L/kg) following the method of Franco & Trapp (2008, 2009, 2010) and using the pKa of 10.59 and the estimated log Kow for the uncharged molecule of 6.56. The correction was performed for pH 5, 7, and 8, which represents 98% of the European soils.

Due to the uncertainty of the measured value according to OECD 121, the calculated value for pH 7 using the method of Franco & Trapp (2008, 2009, 2010) will be used as key value, i.e. for PEC and PNEC calculations.

According to a weight-of-evidence approach, adsorption to solid soil phase is to be expected.

1H-1,2,4 -triazole

Data show that the KOC of triazole in different soils ranges from 43 to 120. The maximum KOC of 120 and the average KOC of 112 indicate indicate mobility in soil. (ECHA disseminated REACH dossier, 2014)

formaldehyde CAS 50 -00 -0

The calculated Log Koc using the formula for nonhydrophics as given in TGD part 3 (2003), resulted in a value of 1.202, suggesting moderate to high mobility of formaldehyde in soil (BASF SE, 2008).