14C-Trifluralin

Table III. Degradation of [14C]trifluralin in a flooded soil (expressed as percent of extracted radioactivity). ...

Degradation of Trifluralin in Water. The amount of 14c recovered from water with time is shown in Table IV. About half of the total 14c (direct count analysis) in water was recovered by extracting twice with ethyl acetate hexane (7 3), indicating that polar metabolites rapidly formed. Also, the concentration of 14c in water increased most rapidly during the first 22 days, after which the rate decreased. Analysis of the water extracts by TLC is shown in Table V. Trifluralin disappeared very rapidly, decreasing to nondetectable levels between 9 and 22 days. Even as early as 2 days only 46% of the recovered 14C was trifluralin. 

The data supports this conclusion since Compound 1, a known photoproduct of trifluralin (9), represents a substantial amount of the total 14c during the first 9 days of the experiment (corresponding to the highest concentration of trifluralin). 

Far more trifluralin was initially recovered (Days 2 and 5) from algae than any of the other organisms (Table IX). However, after 30 days the polar and nonpolar metabolites accounted for 75% or more of the recovered 14C indicating that the algae were also responding to the rapid loss of trifluralin from water. The initial relatively high concentration of trifluralin may account for the lower accumulation of algae biomass in the treated tanks as compared to the control. 

Smith, A.E. (1979) Soil persistence experiments with (14C) 2,4-D in herbicidal mixtures and field persistence studies with triallate and trifluralin both singly and combined. Weed Res. 19, 165-170. 

---