Characterisation and cartography of foetal exposure to pesticides and theirs metabolites in meconium and maternal hair by UPLC-MS/MS
Résumé
Pesticides use has increased since 1940s and one million tonnes are presently dispersed every year in the world. Human exposure to pesticides through the environment and the food is therefore inevitable and the detection of foetal exposure to pesticides is important because some effects on human health have been reported, particularly in the case of an exposure during the early stages of development like the prenatal period. The aim of this study is to characterize the foetal exposure to pesticides and metabolites through meconium (baby's first faeces) and maternal hair analysis. These matrices are representative of the foetal exposure during a wide window of pregnancy since meconium is an accumulative matrix starting its formation from the third month of gestation and all xenobiotics will be accumulating in meconium over the last two trimesters of pregnancy. For this sample collection, a collaboration with 11 nurseries in Picardie was established in order to include 700 couples mother/child, and an analytical strategy for the quantification of pesticides and metabolites based on liquid chromatography-tandem mass spectrometry system was developed. This method targets the main pesticide families used in Picardie (carbamates, organophosphates, pyrethroids, phenylureas and phenoxy herbicides) and 21 compounds were selected. This selection is based on the quantity used in Picardie, their toxicity and their physico-chemical properties. These target compounds have been measured with limits of quantification between 0.2 ng.g-1 and 200 ng.g-1 according to the molecule. These results have demonstrated a significant exposure of the foetus to organophosphate pesticides, dithiocarbamates and pyrethroids that are also used as domestic pesticides. Indeed, the highest detection rate was observed for the metabolites of organophosphates and dithiocarbamates (probably mancozeb which is the main pesticide used in Picardie) with respective percentage of detection of 57.9% and 22.8%. The parent pesticides were rarely detected and only in very low concentration unless for cyfluthrin and cypermethrin which have been quantified in high concentrations between 43.8-479.8 ng.g-1 in 7.6% of the meconium samples. A correlation between concentration measured in meconium and maternal hair was investigated for each couple mother/child, and these first exposure data for the foetus in France have been mapped with geo-localization software.