Effects of agricultural practices on the binding and fate of 14C-parathion in soil
Titel:
Effects of agricultural practices on the binding and fate of 14C-parathion in soil
Auteur:
Racke, K. D. Lichtenstein, E. P.
Verschenen in:
Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes
Paginering:
Jaargang 22 (1985) nr. 1 pagina's 1-14
Jaar:
1985
Inhoud:
The effects of agricultural practices on the formation of unextractable, bound residues of 14C-(ring)-parathion in a Piano silt loam soil were investigated. Relative binding of 14C-parathion in soil decreased with increasing application rates of the insecticide. Thus, with a 1 ppm application rate, 31% of the initially applied radiocarbon was bound after 4 weeks, while binding at application rates of 10 and 45 ppm amounted to only 22% and 17% of the applied dose, respectively. This decreased binding at higher application rates resulted in an increased persistence of extractable 14C-parathion residues. Binding of 14C-parathion in soil was also greater after the insecticide had been uniformly mixed with the soil than when it was applied to the soil surface. Thus, an application of 14C-parathion at 15 ppm resulted in 27% binding after 4 weeks when uniformly mixed with the soil, but only 20% when applied to the soil surface. With both the mixed and the surface applications, more binding of 14C-parathion occurred when the insecticide was applied at 15 ppm in one dosage, rather than in three 5 ppm dosages over a three week period.
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