For the first time in France, the biological concentrations of several environmental chemicals have been measured in a representative sample of the population. The French Institute for Public Health Surveillance (InVS) studies the French population’s exposure to various environmental chemicals by directly measuring the concentration of these substances or their metabolites in individuals’ biological tissues and fluids (blood, urine, hair, etc.). Through such measurements, the environmental component of the National Nutrition and Health Survey (ENNS) provides an initial estimate of the French population’s exposure to a range of chemicals: metals, pesticides, and polychlorinated biphenyls (PCBs). Volume 1 of the report includes a general overview of the study (covering individuals aged 3 to 74 in 2006–2007) and detailed fact sheets for each of the eleven metals or metalloids: antimony, arsenic, cadmium, chromium, cobalt, tin, mercury, nickel, lead, uranium, and vanadium. Each data sheet includes general information (uses of the chemical element, population exposure, fate within the body, and health effects), concentrations observed in the French population, comparisons with French or foreign studies, and factors that may influence the observed concentrations. The data presented in this study provide physicians and public health professionals, for the first time, with reference values that allow them to determine whether an individual or a group of individuals has been exposed to higher levels of chemical substances than those observed in the general French population. (R.A.)