Influence of the polarity of organic matter on the sorption of acetamide pesticides.

摘要

The uptake of three acetamide herbicides (alachlor, metolachlor and propachlor) onto four model organic sorbents is reported. The organic carbon referenced sorption coefficient, Koc, decreased with the increasing polarity index (PI) (O + N/C) of theorganic sorbent. A regression of Kow, solubility, and polarity index indicated that such correlations are very specific to the pollutant class. Apart from the quality of the organic sorbent properties, the hydrophobicity of the herbicide and the presence of functional groups also contributed to sorption. It was concluded that the more polar the solute and/or the organic sorbent, the more likely it is that interactions other than hydrophobic ones will contribute to sorption, causing the currently used Koc - Kow correlations to fail.