M. Arienzo et al., EFFECT OF SOIL CHARACTERISTICS ON ADSORPTION AND MOBILITY OF (C-14)DIAZINON, Journal of agricultural and food chemistry, 42(8), 1994, pp. 1803-1808
The adsorption and mobility of diazinon (O,O-diethyl O-2-isopropyl-6-m
ethylpyrimidin-4-yl phosphorothioate) in 25 soils of different physioc
hemical properties were studied. The adsorption isotherms were found t
o conform to the Freundlich adsorption equation. Freundlich's constant
, K, and the distribution coefficient, K-d, were found to be highly si
gnificantly correlated (p < 0.001) with the organic matter (OM) conten
t when all soils or only those with an OM content above 2% were consid
ered. There was also a significant correlation (p < 0.01) of K and K-d
with the silt plus clay content of soils with an OM content below 2%.
On the basis of the R(f) values obtained by TLC, the pesticide was fo
und to be slightly mobile in 80% and immobile in 20% of the soils stud
ied. A study of the pesticide mobility in soil columns under saturated
flow conditions showed it to be leached from light soils with low OM
contents.