Spatial and temporal distribution of current-use pesticides in ambient air of Provence-Alpes-COte-d'Azur Region and Corsica, France

A total of 59 current-use pesticides were monitored in ambient air samples collected from February 2012 to December 2017, at two rural and six urban sites in Provence-Alpes-Cote-d'Azur Region and Corsica, France. 45 of searched active substances were detected at least in one sample, at frequencies ranging from 0.1 to 98.6%. Among the most frequently detected pesticides, we found the herbicide Pendimethalin (64.6%), the fungicide Tebuconazole (65.9%), and the insecticides Chlorpyrifos (71.5%) and Lindane (98.6%). A wide range of atmospheric concentrations was measured from few pg m(-3) to several hundreds of ng m(-3), with a maximum concentration of 407.79 ng m(-3) for Chlorpyrifos (Cavaillon, May 2012). 17 active substances exceeded an atmospheric concentration of 1 ng m(-3) for at least one sample, including Folpet (147 times/162 detections), Chlorpyrifos (56/520), and Pendimethalin (29/464). The spatial distribution shows that pesticides were detected both in the eight rural and urban sampling sites, suggesting an atmospheric transport from agricultural areas to cities. Classifying the 8 sampling sites according to samples composition, two types of site were observed, those (Aleria, Arles, Avignon, Port-de-Bouc, and Toulon) where a majority of fungicides are found and those (Cannes, Cavaillon, and Nice) where insecticides are dominant. Long-term (6 years) monitoring shows a seasonally trend for each pesticide, depending on pest pressure. Inter-annual variation suggests a downward trend which is consistent with the regional sales data.