We also observed a decrease in the concentration of atrazine over period of time during sorption of this herbicide on soil and soil components. Triazine herbicides, and particularly atrazine, are important environmental contaminants (Meisner et al., 1992 and Barbash et al., 2001), and their behavior was extensively studied. The magnitude and rate of the transformation of the triazine in the presence of NaN3 is of critical importance for the careful evaluation of the parameters characterizing the sorption of this herbicide. The objectives of this study were: (i) to elucidate the mechanism of triazine herbicides transformations in the presence of NaN3. To understand the effects of substitution on the mode of interaction, triazines having different functional groups (i.e., Cl, OCH3 and SCH3) were selected; and (ii) to evaluate the effect of observed transformation on sorption of herbicides to soil.