Evaluation of Incremental Population and Individual Carcinogenic Risks of PCDD/Fs from Steel and Iron Industry in Taiwan by a Site-specific Health Risk Assessment Method

Sinter plants and electric arc furnaces are the most important emission sources of PCDD/Fs. In order to understand the contribution and distribution of PCDD/Fs risk from steel and iron industry, the incremental health risk assessment of PCDD/Fs has been accomplished for the all sinter plants and electric arc furnaces in Taiwan. The study combined the multimedia, multiple pathway exposure modeling and site-specific exposure scenario to evaluate dioxin risks contributed from the 22 major companies of steel and iron industry including 4 sinter plants and 21 electric arc furnaces. The incremental cancer risks to the resident living in the 25 km × 25 km impact range of the above emission sources ranged from 3.10E-10 to 5.73E-06 under the site-specific exposure scenario. Among these 22 emission sources, the stacks with higher exit flows and worse operational characteristics would contribute higher inhalation risks; moreover, the sources located at the major agricultural districts in central Taiwan contributed higher ingestion risks. In conclusion, four sinter plants accounted for more than 24% of total PCDD/Fs exit rates in steel and iron industry, and the incremental risks of these were lower than those of other electric arc furnaces investigated in this study. Furthermore, comparing background cancer mortality for incremental PCDD/Fs risks of steel and iron industry, the total PCDD/Fs population risks contributed from steel and iron industry are low but still cannot be ignored.