Assessing heavy metal exposure from ingestion with multimedia exposure model operating in a GIS environment

International audienceThe last decade has witnessed an increasing interest in assessing health risks caused by exposure to the contaminants present in soils, air, food and water. In this field, Geographic Information System (GIS) may be used to produce maps of exposure and disease to reveal spatial patterns. The SIGFRIED project aims to spatialize an environmental indicator concerning human health using risk assessment methods and mapping environmental disparities. The approach is performed by a risk screening tool which employs an integrated multimedia exposure model able to manage all the steps of the analysis in a georeferenced framework operating in a GIS environment. In this study, we performed a risk assessment of metal exposure (cadmium, lead, selenium, arsenic, chromium, mercury and nickel) with a resolution of 1 km. The modeling was performed on a region of France (Nord-Pas de Calais) characterized by a heavy industrial past. The exposure pathways considered include ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Concentrations of metals on local food were calculated using a soil pollutants geodatabase and bioaccumulation food-chain models. We used water quality data and distance from river as a proxy for fish consumption exposure. Exposure scenarios were defined for different reference groups (age groups, anatomical and dietary properties, fraction of food produced locally). The results showed that the 2 to 7 age group is always the most vulnerable class of receptor. A spatial pattern analysis was performed to highlight hot-spot areas with significantly elevated risk values. In these areas, arsenic (up to 43 % among metals) and vegetables (up to 31 % among considered pathways) are the principal determinants of the calculated risk. In a next step, the same methodology will be use, adding inhalation pathway and organic pollutants, to map environmental inequalities and to analyse geographic cancer disparities in France