2、在PAHs部分，男性暴露量最高為12.6 ng PEQ/day，發生於29歲；女性最高暴露量為9.83 ng PEQ/day，發生於56～59歲間。
3、戴奧辛部分，男性暴露量最高為3.2 pg I-TEQ/day，發生於40~51歲間；女性最高暴露量為2.55 pg I-TEQ/day，發生於57～59歲間。
In this study, the resident’s exposure risk of dioxins and PAHs in Taipei Metropolitan area were assessed. In the assessment a multimedia transport model, the fugacity model, was applied to estimate the concentrations of seventeen toxic Dioxin compounds and six toxic PAHs(Polycyclic Aromatic Hydrocarbons) among the multimedia as the pollutant fate. The considered media includes air, water, soil, sediment, suspended solid, particular matter, plant cover, and the organic film to mimic building surface. The results from the multimedia transport model were then used for the subsequent risk assessment with a Multimedia Total Dose Analysis Model.
To summarize the multimedia transport simulation results and the exposure risk assessment of dioxins and PAHs in Taipei Metropolitan area, this study drew to the following conclusions:
The results of multimedia transport simulation:
1、For accumulated quantity of PCDD/Fs and PAHs in compartments, PCDFs has the least accumulated mass in fish. PCDFs also has the least concentration in fish except 1,2,3,4,7,8-HxCDD that has more concentration in air than in fish. PCDD/Fs and PAHs have the largest concentration on the organic film among the simulated media.
2、The fate of PCDD/Fs and PAHs in the multimedia: Most PCDD/Fs and PAHs were found to accumulate in the soil media eventually. The major sink of PCDD/Fs was the convection in air compartment while PAHs was convection and reaction are two major sink mechanisms for PAHs in air. Both PCDD and PAHs have the highest decayed percentage in the air media.
3、The shortest persistence time of pollutants occurred in air compartment, and the longest persistence time occurred in soil, sediment and suspended solid compartments.
4、The dynamic reaction of PCDD/Fs requires a longer time to reach stable equilibrium when compared to PAHs that requires 100000 hours to reach a stable equilibrium stage.
5、The concentrations calculated by an unified simulation approach (the 17 toxic Dioxin compounds are transferred to a unified 2,3,7,8-TCDD quantity by the TEQ base 2,3,7,8-TCDD toxicity) is less than those simulated by a multiple simulation (the 17 toxic Dioxin compounds are simulated separately) in all media.
For the exposure risk assessment results, the following results were summarized:
1、From the three exposed way, inhalation, take-in and skin absorption, it was found that intake is the main exposed way for Dioxin and PAHs.
2、The exposed dosage of PAHs was assessed and the human intake level is 12.6 ng PEQ/day at the age of 29 years old. The maximum PAHs exposed quantity of the female is 9.83 ng PEQ/day at the age of 56-59 years old.
3、The exposed dosage of Dioxin, was assessed and the human intake level is i 3.2 pg I-TEQ/day at the age of 40-51 years old. The maximum exposed quantity of the female is 2.55 pg I-TEQ/day at the age of 57-59 years old.
4、For PAHs, the carcinogenic risk of the male is 1.14×10-6 and is 1.06×10-6 for female. For Dioxin, the carcinogenic risk of the male is 4.04×10-6 and is 3.76×10-6 for female.
5、Since the combination just concern air, water, soil and sediment media and the local physiological data were not available, the results can be considered as preliminary results only.