Methyl methacrylate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption, other

Remarks:

calculation

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction: EPI Suite calculation V4.11

Principles of method if other than guideline:

Calculation using EPISuite v.4.11 KOCWIN v2.00
Soil Adsorption Coefficient Program

GLP compliance:

no

Type of method:

other: KOCWIN (Soil Adsorption Coefficient Program)

Media:

soil

Specific details on test material used for the study:

SMILES Structure: O=C(OC)C(=C)C

Key result

Type:

Koc

Value:

9.14 L/kg

Remarks on result:

other: MCI method

Key result

Type:

log Koc

Value:

0.961 dimensionless

Remarks on result:

other: MCI method

Conclusions:

Adsorption of MMA was calculated with KOCWin v. 2.0
Koc: 9.14 L/kg (MCI method)
log Koc: 0.961 (MCI method)
Adsorption to solid soil phase is not expected

Description of key information

Koc: 9.14 L/kg
log Koc: 0.961
Adsorption to solid soil phase is not expected.

Key value for chemical safety assessment

Koc at 20 °C:

9.14

Additional information

Supporting information is vaialable in an adsorption/desorption study with radiolabelled methyl methacrylate:

Adsorption of MMA to soil was investigated using 5 different types of soil: sandy loam (=aquatic sediment), loamy sand, two types of loam, clay loam. pH varied from 5.2 to 7.5. Concentrations of test material (methyl methacrylate carboxy 14C) were: 0.5, 0.89, 1.6, 2.8, 5, 8.9 µg/mL. Concentration and assurance of integrity of the test substance throughout the study were confirmed by HPLC analysis. The adsorption phase (24 hours at 23 °C) was followed by 3 desorption phases. Distribution of MMA between aqueous and solid phases was followed by monitoring 14C-levels.

On the basis of its vapour pressure and its low adsorption to soil adsorption constants (Koc) ranged from 8.7 to 72 with an average value of 34 it can be expected that MMA volatizes rapidly from soil. Once adsorbed, MMA was less readily desorbed from soil. Desorption constants ranged from 14.8 to 263 with an average value of 95.

While methyl methacrylate must be classed as being quite mobile under laboratory conditions, care must be taken in predicting and interpreting its actual behavior under field conditions. In an outdoor environment,

other factors such as soil microbial degradation may significantly alter the actual field results from what would be predicted based solely upon the laboratory adsorption / desorption study. Additionally, as no correlation

was noted between the soil organic content and individual Koc values, care must also be exercised in predicting a detailed leaching behavior of methyl methacrylate in other, non-studied soils, based solely

upon an average Koc value obtained in the current study.