Atrazine concentrations greater than 10 ppb were measured at a depth of 140 cm within 40 days after herbicide application in 1990. The 1991 growing season was generally drier than 1990. Average peak concentrations were less in 1991 than in 1990. However, there was evidence of rapid movement of atrazine deep into the root and vadose zones. Generally, peak concentrations of atrazine were measured between 30 and 60 days after application and corresponded closely to major rain events during mid-June.
LWRV soil is very susceptible to atrazine leaching.
Under normal management practices atrazine can leach to groundwater within the season of application, even under nonirrigated situations. Irrigation should be reduced particularly when rain is expected to prevent deep percolation. W.L. Bland, and K. McSweeney. 1993. Water, atrazine, and nitrate flux below the root zone of a sandy soil. Soil Water Conserv.