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Environmental fate & pathways

Adsorption / desorption

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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:
other: 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:
EPA OTS 796.2750 (Sediment and Soil Adsorption Isotherm)
GLP compliance:
yes
Media:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
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 (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.

Applicant's summary and conclusion