Degradation of bentazone, bispyribac-sodium, dinotefuran and imidacloprid in different types of agricultural soils under laboratory conditions by high performance liquid chromatographic

Abstract The degradation and persistence of two herbicides (bentazone BTZ & bispyribac-sodium BPS), and two insecticides (dinotefuran DNF & imidacloprid IMI) into alluvial soil, calcareous soil and sandy soil were investigated following application at 100 µg/g soil at various time intervals; 0, 3, 7, 15, 30 and 60 days by HPLC. BTZ, BPS, DNF and IMI residue dropped after 60 days of incubation to 7.13, 4.85, 53.71, and 7.51% into alluvial soil, 8.58, 5.28, 17.68, and 12.56 % into calcareous soil, and 10.53, 8.94, 53.09, and 13.84% into sandy soil of the initial residue remaining, respectively. DNF, and IMI dissipated slowly compared with BTZ and BPS into three soils. The dissipation of tested pesticides was faster in alluvial soil, followed by calcareous soil and then sandy soil, except of DNF. The persistence kinetics of BTZ, BPS, DNF and IMI into alluvial, calcareous and sandy soil was analyzed using different orders kinetics. The different orders kinetics results showed that first-order model fit the experimental persistence data quite well of BTZ, BPS, DNF and IMI into tested soils with high values of R2 and low values of Δqe% and SSE. The half-life values were 15.27, 16.39 and 17.82 days of BTZ, 11.73, 13.10 and 16.20 days of BPS, 63.01, 23.42 and 75.34 days of DNF, and 14.87, 20.39 and 14.87 days of IMI into alluvial soil, calcareous soil and sandy soil, respectively.