Objectives Acute effects of pesticides are well known, but information on delayed effects (e.g. cancers) is lacking. Detailed knowledge of past occupational exposures to pesticides is required for epidemiologic studies or monitoring survey. Retrospective assessment of occupational pesticides exposure is complex. No occupational pesticides exposure database existed in France. Matphyto program has been initiated to remedy this knowledge gap. This program consists in developing crop exposure matrices (CEMs) to pesticides, to reconstruct historical pesticides use patterns in France.

Methods The Matphyto program aims at developing CEM for each main crop since the 60s in both metropolitan and overseas France. For each crop, data of the pesticide uses are collected and compiled. Different periods and geographical areas are characterised. Three exposure indicators for each active substance and chemical family are defined for each period and each geographical area: the probability, the frequency and the intensity of use.

CEM are validated by agronomists and are freely available on the Internet.

Results First, Matphyto focuses on the main French crops: straw cereals, potatoes, corn and wine-growing. Wine-growing CEM lists the use of pesticides on 9 vineyards with 50 herbicidal active substances, 108 insecticides and 94 fungicides from respectively 41, 25 and 35 chemical families. In parallel, population data are crossing with the CEM of arsenical pesticides. This work allows identifying occupational pesticides exposure indicators such as exposure prevalence of agricultural workers by sex, age, occupational period, region, etc. Moreover, CEMs can be useful to the occupational medicine and to epidemiological studies to assess more precisely pesticides exposure.

Conclusion Matphyto is a national program that covers most of the crops in France. The data will be widely and freely available to support assessment of occupational exposure to pesticides. The first CEMs and first results of CEMs combined with population data will be nearly available.