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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Adsorption of acrylic acid to the solid soil phase is not expected. Acrylic acid is placed into a high to very high mobility class for adsorption and desorption to soils.
Koc = 42.8

Key value for chemical safety assessment

Additional information

The adsorption and desorption characteristics of acrylic acid to five soils, a loamy sand, a clay loam, two loams and an aquatic sediment, were determined in a guideline study according to EPA guidelines - CFR 40 section 796.2750 and GLP regulations (BAMM 1991). The organic carbon content of the soils and sediment used ranged from 0.46 % to 4.58 %. 14C- acrylic acid was used in following the movement of the compound for one adsorption and three desorption steps. Six concentrations of acrylic acid in 0.1 N calcium nitrate solution were used in these experiments. The concentrations of acrylic acid ranged from 0.3 to 9.9 µg/mL of the carrier solutions. The amount of acrylic acid in solution was measured by liquid scintillation counting. The amount of acrylic acid on the soil was calculated from differences in solution concentrations for the adsorption and first two desorptions. The amount on the soil after the third desorption was determined directly by combustion of the soil. Overall, replicate 14C balances ranged from 71.8 to 99.5 %.

Acrylic acid was weakly adsorbed onto the soils and sediment. As related to the carbon content of the individual soils, the average Koc for the adsorption step was 42.8 ± 53.98. This places acrylic acid in a high to very high mobility class for adsorption to soils.

Acrylic acid was less readily desorbed from the soils once adsorption had occurred. Related to the carbon content of the individual soils, the average Koc for the combined desorption steps was 183.1 ± 266.0.

 

These results are supported by QSAR calculations. Based on an estimated Koc of 1.2 calculated by SRC PCKOCWIN v1.66 (corrected log Koc = 0.08), adsorption to solid soil phase is not expected (BASF SE, 2008).

 

The potential for adsorption to soil, sediment, and suspended solids is low to very low (BASF SE, 2008).