GAS AND LIQUID-CHROMATOGRAPHY AND ENZYME-LINKED IMMUNE SORBENT ASSAY IN PESTICIDE MONITORING OF SURFACE-WATER FROM THE WESTERN MEDITERRANEAN (COMUNIDAD VALENCIANA, SPAIN)

A monitoring programme based on gas chromatography (NPD, ECD) using MS D for confirmatory purposes and coupled-column liquid chromatography w as applied to the analysis of pesticide residues in surface water from a predominantly agricultural area of Spain (Comunidad Valenciana). Sa mples analysed by means of enzyme-linked immunosorbent assay gave simi lar results to those obtained by GC (MSD) for the determination of tot al triazines. The test employed had the advantages of a simple test pr ocedure, short analysis time and high confirmatory value. Nevertheless , the multiresidue character, accuracy and unequivocal identification of individual pesticide residues of GC (MSD) make this technique the m ost appropriate for environmental monitoring programmes. In this monit oring programme about 200 samples were analysed between 1993-1994. 27 different pesticides were detected in 91 of these samples. The pestici des more frequently detected were dimethoate, methidathion, endosulfan A and B, endosulfan sulphate and pirimicarb. The highest concentratio ns found were 39.9 mu g L(-1) of dimethoate, 10.6 of pirimicarb and 10 .6 of methidathion.