Effect of Amendments on the Adsorption and Mineralization of Atrazine in an Agricultural Soil

Atrazine is one of the most widely used herbicides in agriculture, which has been detected as a contaminant in surface and groundwater. In this work atrazine attenuation was studied in soils amended with construction waste, ground corn straw and biosolids.. Adsorption of atrazine was carried out in batch and column systems, four percentages of amendments in the soil were evaluated: 0 (control, 0 g/kg), 5, 10, and 20 g/kg. The physicochemical and biological behavior of the amended soils in relation to the retention of atrazine was analyzed. Organic matter and biological activity of the amended soil favored atrazine adsorption in comparison with the control soil. The experimental data were best adjusted to the pseudo second order and Freundlich model indicating that atrazine adsorption on amended soils was controlled by chemical adsorption and heterogeneity of the materials. The results show that the amended soils are good materials for the adsorption, retention and degradation of atrazine. The mineralization half-lives of atrazine depend on the amendment added to the soil. The construction waste amendment is composed of a mineral mixture, which favored the generation of aggregates of different compounds, and these could provide sorption sites, electron donor-acceptor interaction, and general stability to the soil. The ground corn straw amendment with a high organic matter content promotes the development of microorganisms that may degrade atrazine. The conditions studied are applied to a soil from an agricultural land that produces corn where herbicides and chemical fertilization have been applied. However, it should be considered that the soil is a living, complex and dynamic entity.