Abstract
The behavior and disappearance of the herbicides chlomethoxynil and benthiocarb (thiobencarb) in soil and surface water were investigated using a model paddy field (an ordinary culture and a bare ground) under a controlled rate of drainage. The concentrations of chlomethoxynil in the effluent water were 4-6ppb at maximum and decreased gradually to 0.1ppb within 60 days after its application. A similar residue pattern of chlomethoxynil in water was observed both in ordinary culture and under bare ground conditions. A positive correlation (r=0.96) was observed between the concentration in soil and that in water. Benthiocarb concentration in the effluent water was 380ppb at maximum and decreased rapidly below the detection limit (1ppb) in 25-30 days after the application. The estimated half-life values of chlomethoxynil and benthiocarb in soil were 10-22 days and 10-30 days, respectively.
