Developpement d'un indicateur d'evaluation des impacts potentiels sur la sante humaine: Application aux emissions de HAP prioritaires dans la region des Grands Lacs et du St-Laurent

This project looks at the evaluation of potential impacts on human health from an inventory of environmental emissions.The IMPACT 2002 model was adapted to the Great Lakes and St-Lawrence region which resulted in the GL model. The performance of the GL model is comparable to that of the IMPACT 2002 model. It is thus shown that the IMPACT 2002 model can be adapted to a smaller region with different geographic characteristics.The calculation of the EEF of a substance is developed by combining the intake fraction normalised with benzo[a]pyrene (B[a]P) with the TEF. The EEF are designed to weigh an inventory of emissions to obtain a TES. Throughout this project, it is demonstrated that the TES allows a distinction between emitting sources in terms of human health impact, and that the EEF allows a distinction between substances. The TES is an evaluation tool of potential human health impacts.By using the GL model to calculate iF specific to the Great Lakes and St-Lawrence region, the EEF for the 16 priority PAH in the region are calculated. Although there are some issues around environmental concentrations estimates, a set of physico-chemical data provided by Li et al. (2010) for the 16 PAH allows a calculation of iF with the GL model, since the predicted agricultural concentrations are closer to the observed range---the iF being in function of the agricultural concentrations.The two research hypotheses guiding the project are: (I) It is possible to adapt to the Great Lakes region an existing multimedia multi-pathway model---IMPACT 2002---and that the resulting model can provide acceptable estimates for environmental and food concentration, as well as intake of pollutant by the population. Acceptable estimates are defined as being equal to measured values plus or minus one order of magnitude, or as following the same trend as the original model. (II) It is possible to develop a relevant indicator of impacts on human health from emissions which allows a distinction between pollutants and consequently between emitting sources---the Toxicity Equivalency Score or TES---by combining an existing indicator of pollutant intake---such as the intake fraction (iF)---to an existing indicator of toxicity---such as the Toxicity Equivalency Factor (TEF). More specifically, the objectives of the project are: (1) To test the adaptability of the IMPACT 2002 model to the Great Lakes and St-Lawrence region (2) To extend the TEF concept to weigh inventory emissions rather than the intake of pollutants and develop the TES (3) To calculate a set of Emission Equivalency Factors (EEF) for 16 priority PAH (polycyclic aromatic hydrocarbons) in the Great Lakes and St-Lawrence region (4) To show with a concrete example of emissions in a defined area of the Great Lakes region which PAH has the most impact on human health and which emitting source has the most potential impact on human health, by using the developed methodology.The set of EEF developed for the 16 priority PAH is used to weigh the inventory of emissions in the St-Lawrence County, in the state of New York. The resulting TES by source indicates that the potentially most threatening source of PAH for human health is the metallic industry, more specifically the production of aluminum. The most threatening substance among the 16 PAH in the region is B[a]P.The results of this project meet in part one of the objectives of the GLAD (Great Lakes Air Deposition) programme by allowing a better understanding of the emitting sources, the fate and exposure of the 16 priority PAH which are substances of concern in the Great Lakes region.