Adsorption of Fungicides in Chilean Soils Incubated With Biosolids

Abstract

The efficiency of the adsorption process of the fungicides Captan and Thiram was studied in four Chilean soils from the VI [O´Higgins, (HGS) The values of parameters Kf and n from the Freundlich equation indicated an increase in the adsorption of fungicides incubated with biosolids (1% and 10%) with respect to natural soil. A high Kf value (12.1) for DIG-Thiram and a lower Kf value (4.3) for MAO-Captan interaction were observed for natural soils, while in soils incubated with biosolids (10%) the greatest value was (20.3) for DIG-Thiram and the lowest Kf value (10.2) for MAO-Captan. In general the high Kf values for Captan and Thiram were correlated with organic carbon content in the natural and incubated soils, except for the interaction THL-Thiram, in which inorganic compounds of soils (clay) were dominant.The distribution constant between solid-liquid phases (Kd) increased in soils incubated with biosolids; the magnitude of this constant was more significant with Thiram. The same behavior was observed for the constant related to organic carbon constants (Koc).The results of this work confirm that amending soils with biosolids is beneficial for immobilizing fungicides and helps prevent the percolation of Captan and Thiram through the soil profile and into groundwater

Bio-adsorption of triadimenol pesticide from aqueous solutions using activated sludge of dairy plants

“…However, the high cost of activated carbon production has put forward efforts to search for low-cost raw materials such as agricultural wastes and by-products, sewage sludge, discarded tyres and asphalt [26,27]. In a recent study carried out on the adsorptions of fungicides by soils incubated with biosolids, Copaja et al [28] concluded that incubating soils with biosolids increased the adsorptions of the fungicides. Nevertheless, little information is available in the literature for using activated biomass as an adsorbent for pesticides [29,30].…”

Solubilization and Interactions of Thiram with Surfactants: Micellar Effects on Adsorption Characteristics of Thiram onto Activated Carbon

“…Adsorption is a key process that largely controls the behavior of pesticides in soil, determining their distribution between the soil and the water system. [2,3] Several studies have been dedicated to adsorption studies of thiram and some of the reported sorbents include lignins, waste resulting from a coal mine, SiO 2 particles, activated carbon (AC), sepiolite, [4][5][6][7][8][9] and different soil types. [10] Recently, a strong interaction between thiram and commercial humic acids, suggesting the relevance of the organic matter content on thiram sorption onto soils and effect of soil organic matter on thiram sorption and desorption, has been reported.…”