The results of a 3 year survey for the presence of residues of 118 mostly u
sed pesticides in surface and ground waters of Greece are presented. Pestic
ide residues were detected in 47 of the 252 samples (19%). Residues of 26 d
ifferent compounds were detected in the samples; alpha -HCH was the most fr
equently detected pesticide. The concentrations of the pesticides detected
were from 0.001 to 1 mug/L, with the majority of the concentrations (94%) f
ound lower than 0.1 mug/L.