Methacrylic acid

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

EPA guideline similar to OECD-guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OTS 796.2750 (Sediment and Soil Adsorption Isotherm)

GLP compliance:

yes

Media:

soil

Test material

Test material information

Constituent 1

Reference substance name:

Methacrylic acid

EC Number:

201-204-4

EC Name:

Methacrylic acid

Cas Number:

79-41-4

Molecular formula:

C4H6O2

IUPAC Name:

methacrylic acid

Test material form:

liquid

Specific details on test material used for the study:

Glacial methacrylic acid: purity: 99.7 %;
Methacrylic acid-carbonyl-14C (in acetonitrile),
radiochemical purity: > 98 %

Study design

Batch equilibrium or other method

Details on test conditions:

The adsorption and desorption of methacrylic acid was examined on five soils: sandy loam (aquatic sediment), a loamy sand, two loams, a clay loam. The pH range of the soils was 5.2 - 7.5. The organic matter ranged from a low of 0.8 % for  the loamy sand to 7.9% for one of the loams. The range of organic carbon  of the soils was 0.46% to 4.58%. Six concentrations of methacrylic acid-carboxy-14C, ranging from 0.5 µg/ml to 8.9 µg/ml of the acid in 0.01 N calcium nitrate were used for the studies.

Results and discussion

Any other information on results incl. tables

Methacrylic acid was weakly adsorbed to soil. Among the soil types tested, methacrylic acid was most strongly adsorbed to loamy sand, the soil having the lowest organic carbon content (0.46%). The Freundlich coefficient values for adsorption phase ranged from 0.076 to 0.24. For the five soils the Koc's for methacrylic acid ranged from 1.7 to 52. The average adsorption Koc was 15, log Koc 1.18, (with a standard deviation of 21) which places methacrylic acid in a very high mobility class rating (compounds with a Koc in the range 0 to 50 are classified as having a very high degree of mobility). 

 

Once adsorbed to the soil, methacrylic acid was less readily desorbed. The Freundlich coefficient values for the three desorption phases ranged from 0.069 to 2.04; calculated desorption constants ranged from 3.2 to 144, which would again place methacrylic acid in a high mobility class rating.