The application of the EHHRA-GIS tool for the assessment of human health risk in the Pace valley of Messina

Due to industrial and civil activities, large quantities of toxic and carcinogenic substances are released into environment and represent a potential hazard to human health of exposed receptors. The human health risk assessment procedure become complex and time expensive when the analyzed geographical area is characterized by the presence of multiple sources, multi-exposure pathways and multiple typologies of receptors. The EHHRA-GIS tool is an innovative approach for estimating the human health risk through an integrated procedure able to manage all the steps of the analysis in a georeferenced structure with a graphical user interface. As a result the developed tool is a Decision Support System useful to support stakeholders and local authorities interested in assessing and managing human health risks in a territory where several industrial sources emit dangerous pollutants able to impact on different environmental media. The aim of risk assessment in EHHRA-GIS is the calculation of the upper-bound excess lifetime cancer risk and noncarcinogenic hazards for each of the pathways and receptors identified in the study area. Summing risks and hazards for each specific receptor, through all possible pathways of exposure, it is possible to obtain a computation of total individual risk and total hazard quotient and display on maps iso-risk contours. In order to calculate the spatial and temporal distribution of the concentrations in different environmental media, the user can employ predictive and transport models, multimedia and food-chain models integrated in the tool. The procedure is completed with the application of a sensitivity analysis with the aim of investigate how risk values are dependent on variability and uncertainty in the factors contributing to risk. In this work the EHHRA-GIS tool has been applied for the assessment of human health risk in the area of the valley of the Pace torrent situated in the north zone of the city of Messina (Italy). The pollution sources present in the area are: a Municipal Solid Waste Incinerator active since 1979, a dismissed landfill of urban solid waste used for about 30 years, a platform of urban solid waste treatment which causes the presence of heavy vehicles, and two open pits for the production of bitumen. The land use of the study area is predominately agricultural and residential. The assessment has considered all the environmental media studying the distribution of pollutants using air dispersion model for emission of the incinerator and the two sites for the production of bitumen, soil and groundwater dispersion models for release of leach ate from the dismissed landfill into the subsoil of the study area. The calculation of the total human health risk in the area is useful in order to reduce the emissions considered according to the imminent application of the IPPC Directive.