| Summary: | 碩士 === 國立臺灣大學 === 職業醫學與工業衛生研究所 === 89 === Objective: Assessing site-specific carcinogenic risks of incinerator-emitted dioxins and risk transfers among the areas covered by 9 municipal incinerators in Taiwan. Methods: We used actual emission data and the industrial source complex model (ISC3) to determine the dioxins impact areas within the 8x8 km simulation region grids surrounding the incinerators. We used geographic information system (GIS) to plot the simulated results. We then used modified TRI-multimedia model to estimate cancer risks in individual impact areas. We based on the surveyed agricultural production information to calculate risks for exposure scenarios of sufficient and insufficient foods production for consumption in each impact area. We also used information of food flows between impact areas to calculate risk transfers among 9 incinerators. Results: The carcinogenic risks of dioxins under the exposure scenarios of sufficient food production ranged from 1.43×10-8(Jia-yi incinerator) to 7.08×10-5(Nei-hu incinerator). The carcinogenic risks of dioxins under the exposure scenarios of insufficient food production ranged from 8.69×10-8 (Kaohsiung incinerator) to 1.07×10-6 (Tai-chun incinerator). The food ingestion was the main exposure pathway, which accounted for 64~88% of total dioxins intake among 9 impact areas. For the 9 major food items consumed by residents in the impact areas, eggs (14%~35%) and chicken (11%~26%) were two main routes of dioxins exposure in the sufficient food production scenario, while chicken (8%~78%) and vegetables (0.2%~81%) were two main routes of dioxins exposure in the insufficient food production scenario. Significant risks of dioxins were transferred among incinerators, which accounted for 0.2%~99% among the incinerators. Tai-chun incinerator was the major export source of risk to 6 other incinerators except the Nei-hu and Mu-cha incinerators. For these 6 incinerators, the Tai-chun incinerator accounted for their 51-88% imported risks. Conclusions: We should consider risk transfers among incinerators through routes of food consumption in assessing health risks associated with incinerator-emitted dioxins in Taiwan. We should also emphasize on analyzing dioxins contents in eggs, chicken, and vegetables in order to improve dioxins-related health risk assessments in the future.
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