Environmental characterization of exposure to toxic wastes containing mercaptan, aromatic hydrocarbons and hydrogen sulphide (Abidjan, Côte d'lvoire)

Environmental characterization of exposure to toxic wastes containing mercaptan, aromatic hydrocarbons and hydrogen sulphide (Abidjan, Cote d'lvoire) In 2006, toxic waste discharged in various parts of Abidjan, Cote d'lvoire, poisoned many people, some of them fatally. The authorities defined an impact zone of 200 m around each site as the area as the site for unprecedented population protection and health emergency measures. Nonetheless, the sudden, uncontrolled and dispersed nature of the pollution made it difficult to apprehend its environmental consequences. By combining a geographical survey of transects and a retrospective cross-sectional epidemiological survey, we sought to characterise the inhabitants' vulnerability to exposure to the toxic pollutants and the extent of their effects. Multi-source information (from external data, information about the built environment and socio-environmental and epidemiological Surveys) was collected and organized in a GIS by geo-referencing techniques. The study produced an updated mapping of the spatial distribution of the polluted sites: 76 sites containing more than 500 tons of toxic waste were identified and mapped, mainly in poor neighbourhoods and slums. The study also showed that the radius of the zone affected varied from 0.4 km to 3 km, much higher than the officially defined and accepted 0.2-km radius. Finally, it showed that several environmental factors influenced people's vulnerability to toxic waste exposure: the size of the site affected, the length of time for which the pollutant was on the site, and weather conditions (humidity, direction and speed of prevailing winds). In the future, these factors should be taken into account in defining vulnerable zones in all situations involving toxic waste dispersion