El. Kruger et al., MOVEMENT AND DEGRADATION OF [C-14] ATRAZINE IN UNDISTURBED SOIL COLUMNS, Environmental toxicology and chemistry, 12(11), 1993, pp. 1969-1975
The movement and degradation of [C-14] -atrazine were studied in undis
turbed soil columns (15 x 60 cm) taken manually from a field with no p
revious pesticide history. The experiment was conducted indoors under
controlled temperature conditions. Three weeks after application of [C
-14]-atrazine (2.2 kg a.i. per hectare) to the soil surface, the colum
ns were leached at weekly intervals for 12 weeks. Approximately 1.2% o
f the applied C-14 was recovered in the leachate over the 12-week peri
od, which corresponds to an atrazine (plus degradation products) conce
ntration of 7.6 mug/L. On completion of the last leaching event, the c
olumns were cut into 10-cm increments and analyzed for [C-14]-atrazine
and degradation products. Seventy-seven percent of the C-14 applied t
o soil columns remained in the upper 10 cm and included primarily atra
zine (9%) and soil-bound residues (57%). Deethylatrazine was the predo
minant degradation product in the top 10 cm (3.6%). Other degradation
products were found in the top 10 cm at relative concentrations of dei
sopropylatrazine > hydroxyatrazine > didealkylatrazine > deethylhydrox
yatrazine > deisopropylhydroxyatrazine. Uncharacterized polar metaboli
tes in the top 10 cm accounted for 6% of the applied C-14. Atrazine, d
eethylatrazine, and deisopropylatrazine were found at all depths. In a
ddition, didealkylatrazine was detected to the 50-cm depth, hydroxyatr
azine to the 30-cm depth, and deethylhydroxyatrazine to the 20-cm dept
h.