Many studies over the past four decades have established that pesticides can move downward to reach the water table at detectable concentrations. Once in ground water, pesticides and their degradation products can persist for years.
Scientists at the U.S. Geological Survey (USGS) examined several of the factors that can influence the likelihood of pesticides and their degradation products being detected in shallow ground water.
The study revealed that the pesticides and degradation products detected most frequently were predominantly from two classes of herbicides -- triazines and chloroacetanilides.