Studies on mobility and degradation pathways of terbuthylazine using lysimeters on a field scale.
Terbuthylazine [N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine] degradation pathways in agricultural soils were evaluated by following the appearance and mobility of its main transformation products: dealkylated and hydroxylated derivatives. Three experimental degradation studies in open field were performed in different hydraulic conditions: constant hydraulic head on topsoil, achieved to simulate the highest-risk situation for the aquifer, intermittent artificial precipitation to simulate a medium-risk situation; and natural precipitation to reproduce the lowest-risk condition. Concentrations of terbuthylazine transformation products derived from dealkylation and hydroxylation reactions were measured in leachates and soil samples collected during the three experiments. Desethylterbuthylazine (DET) and deethylterbuthylazine-2-hydroxide [DETH; 4-amino-6-terbutylamino-(1,3,5)-triazine-2-OH] were found to be the highest-leaching compounds and therefore can be considered as potential pollutants for aquifer contamination.
Guzzella
L
L
Water Research Institute-CNR, Via della Mornera 25, 20047 Brugherio (MI), Italy. guzzella@irsa.rm.cnr.it
Rullo
S
S
Pozzoni
F
F
Giuliano
G
G
D000383:Agriculture; D004784:Environmental Monitoring; D005544:Forecasting; D006540:Herbicides / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D011891:Rain; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D014227:Triazines / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D014873:Water Pollutants
D006540:Herbicides; D012989:Soil Pollutants; D014227:Triazines; D014873:Water Pollutants; C037565:terbutylazine; C000598075:desethylterbuthylazine