Measurement of Atrazine Adsorption onto Surficial Sediments (Natural Surface Coatings)——New Evidence

To reveal the relative contribution of the components, Fe, Mn oxides or organic materials(OMs) in the surficial sediments(SSs), and the natural surface coating samples(NSCSs) to adsorbing atrazine(AT), a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting(NLSF) to estimate the relative contribution of the com-ponents. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, be-fore and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs(NSCSs) facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs(NSCSs) particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar ba-sis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in con-trolling the environmental behavior of AT in an aquatic environment.