ABSTRACT
Even if the environmental risk from pesticides was recognized relatively early, the occurrence of pesticides in groundwater was detected much later. The high concern for pesticide risk in the 1960s was mainly related to DDT and other organochlorinated compounds. They were banned or severely restricted in all developed countries at the beginning of the 1970s. As for other less persistent pesticides, the general belief was that these compounds could not leach into groundwater under normal conditions. This perception was mainly due to a lack of knowledge about the important features of chemicals movement through the soil. 1
