Sorption behaviour of chlorophenols and triazine herbicides in reference euro-soils

Abstract

The influence of different soil sorption-controlling properties on sorption behaviour of chlorophenols (2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol) and triazine herbicides (chlorotriazines atrazine and simazine, and methylthiotriazines ametryn and prometryn) in natural sorbents was studied. Experiments were carried out with six European reference soils differing in soil organic matter content (SOM), grain size distribution, cation exchange capacity, and acidity, as well as in silt, clay, sand, iron oxide and aluminium oxide content. Freundlich isotherm coefficients K f and 1/n as well as organic matter sorption coefficient and free energy change were calculated for all compounds in all sorbents. The sorption intensity for chlorophenols increased with increase of SOM, cation exchange capacity and sorbent sand content and decreased with increase of sorbent pH, silt and clay content. For chlorotriazines atrazine and simazine, statistically significant positive correlation between K f sorption coefficients and SOM was obtained and the sorption was also favoured by lower content of coarse- and medium-grainy fractions of silt.