OCCURRENCE OF 38 PESTICIDES IN VARIOUS FRENCH SURFACE AND GROUND WATERS

Thirty eight active substances were determined on a seasonal basis at 13 sampling points covering the most significant agricultural areas as well as types of culture throughout France. The pesticides selected included 19 herbicides, 7 insecticides and 12 fungicides which represented for each category, respectively 88%, 50% and 80% of the quantities applied in France in 1987. The sampling points included 11 ground waters with different depths and geological characteristics; the last two points were sampled from the river Seine and river Marne which account for 40% of the water supply of the Paris area. Seven multiresidue analytical techniques were developed to measure the 38 pesticides at or below the 100 ngl-1 level of the drinking water EEC directive. Gas chromatography-mass spectrometry could be used to quantitate 36 substances following solvent extraction (benzene, methylene chloride) or other sample preparation methods (hydrolysis, methylation, oxidation). The remaining substances were analysed by HPLC. Recovery data were determined for each method. Only atrazine and simazine were detected above the 0.1 microgram per litre level primarily in the surface waters. The following substances were occasionally found at levels between 0.1 and 0.05-mu-gl-1: cypermethrin, dimethoate, ethofumesate, mecoprop, vinchlozolin.