The lead found today in the air, soil, water, food, and dust stems primarily from past and present human activities. The public is exposed to lead through multiple routes: inhalation of air, ingestion of dust settled on the ground, and ingestion of food or water containing lead. Furthermore, the presence of non-ferrous metal smelters or cadmium-bearing ore mining operations can lead to significant cadmium contamination of the soil, and it is well established that cadmium is easily transferred from the soil to plants. In the study area, two non-ferrous metal production plants, both over a century old, have caused soil pollution with lead and cadmium. These two plants are approximately 3.5 km apart and located in two departments: Nord and Pas-de-Calais. The area in question has a population of approximately 60,000, distributed equally across the two departments. The plant located in the municipality of Auby (Nord) produces zinc, and the plant in Noyelles-Godault (Pas-de-Calais) primarily produces lead and zinc. The various thermal processes used for zinc and lead production have generated significant emissions of heavy metals that have settled on the surrounding soils. Today, this is primarily a legacy pollution issue, as atmospheric and aquatic discharges have decreased significantly over the past two decades. Nevertheless, they have remained constant in recent years. At the Noyelles-Godault plant (MetalEurop), outside the plant’s main discharge point, other filtered discharges—and especially unfiltered discharges—still represent significant pollution flows. The change in the manufacturing process that would allow for a radical reduction in discharges appears difficult to implement; therefore, as part of a draft supplementary prefectural order, a number of measures have been proposed aimed at minimizing discharges related to work organization (transportation, cleaning, storage, stockpiling, etc.) and, in particular, resuspension.The modification in 1975 of the manufacturing process at the Auby plant (Union Minière) eliminated lead and cadmium emissions into the air. The problem of cadmium discharges into the water remains and must be re-examined. Concentrations in sediments sampled from the Deûle Canal have decreased significantly since 1982 but remain high, especially near the plants. At this time, we do not know the consequences of these high concentrations on the aquatic environment, their spread along waterways, or whether solutions exist to reduce this pollution. (R.A.)