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Environmental fate & pathways

Adsorption / desorption

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Endpoint:
adsorption / desorption: screening
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.
Reason / purpose:
read-across source
Related information:
Composition 1
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
other: HPLC column
Test material information:
Composition 1
Radiolabelling:
no
Test temperature:
Column temperature 35 °C
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: Alliance Separation Module 2695
- Detection system: Dual lambda absorbance detector 2487


MOBILE PHASES
- Type: 30/70 methanol/water (neutral); 30/70 methanol/phosphate buffer (pH 2.0)
- Solutes for dissolving test and reference substances: water (lactic acid); methanol (phenol)


DETERMINATION OF DEAD TIME
- Method: by means of homologous series / by inert substances which are not retained by the column


REFERENCE SUBSTANCES
- Identity: Phenol


DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 10 µl; 209 ng (neutral), 135 ng (pH 2)
- Quantity of reference substances: 10 µl; 100 ng


REPETITIONS
- Number of determinations: all samples were measured in duplicate; controls were injected once


EVALUATION
- Calculation of capacity factors k': Not calculated
- Calculation of retention times: Not given other than in (single) chromatogram run printouts
- Determination of the log Koc value: <1.32 (i.e. < phenol log Koc)
Type:
Koc
Value:
< 20.9 dimensionless
Type:
log Koc
Value:
< 1.32 dimensionless
Details on results (HPLC method):
Lactic acid eluted before phenol; phenol has a designated log Koc of 1.32. No relevant differences in the results were observed at neutral pH and pH 2.0.
Validity criteria fulfilled:
yes
Conclusions:
Lactic acid log Koc < 1.32.
Executive summary:

The adsorption coefficient (Koc) of lactic acid 93 % aq. on soil and on sewage sludge was determined using high performance liquid chromatography (HPLC). The Koc and log Koc value of the test substance at neutral pH and at pH 2 was < 20.9 and < 1.32, respectively.

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Endpoint:
adsorption / desorption, other
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.
Reason / purpose:
read-across source
Related information:
Composition 1
Principles of method if other than guideline:
QSAR calculation
GLP compliance:
no
Type of method:
other: QSAR
Test material information:
Composition 1
Type:
Koc
Value:
1 L/kg
Remarks on result:
other: Estimate from Molecular Connectivity Index
Type:
Koc
Value:
0.222 L/kg
Remarks on result:
other: Estimate from Log Kow
Validity criteria fulfilled:
not applicable
Conclusions:
The estimated KOC based on the KOW data equals 0.2218 L/kg. The calculated KOC from the molecular connectivity index is 1L/kg.
Executive summary:

Both estimated soil organic carbon-water partitioning coefficients indicate that the substance does not inherent a high tendency to adsorb on to soil particles, but is more likely to be found in aquatic compartments. The estimated KOC based on the KOW data equals 0.2218 L/kg. The calculated KOC from the molecular connectivity index is 1 L/kg.

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Description of key information

Both estimated soil organic carbon-water partitioning coefficients indicate that the substance does not inherent a high tendency to adsorb on to soil particles, but is more likely to be found in aquatic compartments. The estimated KOC based on the KOW data equals 0.2218 L/kg. The calculated KOC from the molecular connectivity index is 1L/kg. These QSAR calculations are supported by an experimental study, indicating that the KOC of lactic acid is much lower than 20.9.

Key value for chemical safety assessment

Additional information