Uptake and Translocation of Fenitrothion and Thiobencarb in Rice Plant under Laboratory and Filed Conditions

This study investigate the uptake and translocation of fenitrothion insecticide and thiobencarb herbicide in rice plants.This study is carried out under laboratory conditions, two concentrations (1 and 10 μg/g) and lysimeter conditions at a concentration of 25 μg/g.Significant differences in pesticide uptake by rice were observed between the two laboratory treatments (1 and 10 μg/g) across all time intervals, as well as in the cumulative amounts.After reaching maximum concentrations, a decrease in uptake was noted, likely due to biodegradation and plant growth dilution.The average bioconcentration factor (BCF) of thiobencarb was higher than that of fenitrothion, indicating a greater ability of rice plants to absorb and accumulate thiobencarb.The BCFs for both fenitrothion and thiobencarb were higher at lower concentrations (4.85 and 5.67) compared to higher concentrations (0.55 and 0.89), suggesting that the uptake capacity was saturated at low concentrations, limiting the rice plants' ability to accumulate the pesticides at varying initial concentrations under laboratory conditions.The recovery rates of fenitrothion and thiobencarb from soil and rice plant samples, as determined by HPLC, exceeded 80%.After 10-week period, fenitrothion and thiobencarb were not detectable in soil or rice under field conditions.Additionally, two metabolites of fenitrothion were tentatively detected in rice plants, while two metabolites of thiobencarb were detected in soil, with concentrations of 1.5 and 1.0 μg/g for metabolites I and II, respectively.One thiobencarb metabolite (metabolite I) was detected in rice plants at a concentration of 5 μg/g.