Fate and Mobility of Imidacloprid and Abamectin Residues in Green House Soil

Recently, one of the most indispensable methods in the usage of pesticides in agriculture and crops which make great improvement toward this crops. On the other hand there are demerits of using such pesticides toward the human health. In this study two pesticides were selected, imidacloprid ( Konfidor ®) and abamectin ( Vertimec ® ) as examples of pesticides that are released into the environment, both are marketed in the Palestinian market, and the widely used in Palestine based on the results of the survey that was conducted. In this research we have investigated the adsorption behavior of the two pesticides on soil, the effect of temperature, pH, adsorbent dosage, contact time and concentration on the adsorption process, all were studied using UV-Vis spectrophotometry. Results indicate the highest percentage of imidacloprid and abamectin removal was 13.4 % and 7.5 % respectively when adsorbent dosage 3 g. percentage removal of imidacloprid and abamectin increases when the concentration decreases, the maximum percentage removal reached 17 % for imidacloprid and 19 % for abamectin when their concentrations was 10 mg/L and 1 g soil. At low pH "1.5" the percentage of imidacloprid removal increases reached to 12.3 %, but the decrease of imidacloprid removal at high pH "12" is highly extreme reached to 7.3 % . At high pH "12" the percentage of abamectin removal increases reached to 15.4 %, but the lowest percentage of abamectin removal at pH 7 reached to 9.1 %. The effect of temperature on adsorption by soil has also been investigated in the range of 15–47°C. The results indicate that imidacloprid and abamectin soil adsorption in this study was increased with increasing temperature. The results showed that the equilibrium time for imidacloprid and abamectin adsorption is 150 min, but most of the adsorption attained within the first 15 min. This study was aimed to assess the adsorption, leaching potential, fate and mobility of imidacloprid and abamectin in soil. To understand mechanism of adsorption and factors affecting , the experiments were carried out under laboratory conditions. Adsorption study was divided into kinetic and equilibrium sections. The evaluation of kinetic data was done through pseudo first and second order models and intra-particle diffusion model. It was found that kinetic adsorption of imidacloprid and abamectin on soil followed pseudo second order. Langmuir and Freundlich isotherms were used to explain equilibrium adsorption, from these isotherms it was evaluated that Freundlich isotherm was obeyed well.