(The project of emission investigation and health risk access of air toxic pollutants (Dioxins and heavy metals) from the stationary sources.)
The scope of work for this project includes: 1) emission inventory establishment and update; 2) monitoring for stationary emission and the ambient environment; 3) reviewing the control strategy and risk assessment; 4) providing the technique and administrative assistance for the EPA.
The total dioxin emission quantity in Taiwan area is estimated to be 23.8~210.7 g I-TEQ/year in 2008 with an average value as 58.9 g I-TEQ/year. While in 2009, the total dioxin emission quantity is 23.1~237.1 g I-TEQ/year with an average value as 52.8 g I-TEQ/year. The major pollution sources include the electric arc furnaces and sinter plants. As for the heavy metal parts, the total emission quantity for lead is 10.14 metric tons/year, cadmium is 1.01 metric tons/year, mercury is 1.37 metric tons/year and arsenic is 4.03 metric tons/year in 2008. The major emission sources include the waste incinerators, coal electric utilities and cement kiln.
For heavy metal emission, this study investigates industries such as: coal-burning boilers, high technic industry, waste battery, waste tubes recycle plant as well as steel electrical furnace. . Based on the investigation data, the emission concentration of the coal-burning boilers is close to recent annual concentration. Lead and mercury were recovered by waste battery and tube recycle plants, and both emission concentrations imply with current emission standards. This shows the pollution control facilities can reduce emission quantity effectively.
For dioxin and heavy metal emission from agricultural waste open burning, this study executes experiments on bell apple, sweetsop, guava, to obtain relevant emission coefficient and included in the emission inventory for agricultural waste open burning.
For the ambient dioxin monitoring, this year is target on general monitoring station, traffic monitoring station and areas around major pollution sources. The monitoring frequency is once every season, in addition, dioxin-like PCB is included for analysis. The concentration resulted from seasonal monitoring range from 0.006 pg WHO2005-TEQ/m3 ~ 0.547 pg WHO2005-TEQ/m3, the monitoring results are fluctuated significantly with seasonal changes. The highest concentration monitored is at the area of one major pollution sources, the Quan-Hsin Industrial Area at Changhua County, which is 0.324 pg WHO2005-TEQ/m3and 0.547 pg WHO2005-TEQ/m3 on January and May 2010, respectively. All other monitoring results are lower than the Japan’s ambient air dioxin standard (0.6 pg WHO2005-TEQ/m3).
For the ambient heavy metal monitoring, this year is target on general monitoring station and traffic monitoring station. The monitoring results show ambient concentrations of Lead, Arsenic, Cadmium and Nickel are all below Euro’s ambient air quality standard, no matter it was measured at general or traffic monitoring stations. While concentrations of Arsenic, Cadmium, Nickel and Lead measured at Chiahsin Primary School at Chiayi County and Nanzi area at Kaohsiung are higher than data from other stations. This is as the result of higher PM10 concentration.
This study purpose the following actions based on planning and reviewing of current emission control strategy and results of risk assessment. For air emission standard of stationary pollution sources, this study suggests to revise the control standard of Lead to 1.0 mg/Nm3 and Cadmium to 0.02 mg/Nm3.
This study carries out multi-medium risk assessment in Central Area, where with most of the dioxin emission sources. The results show the cancer risk value for all the cities and counties are below one in one million. Among them, the cancer risk value of Changhua County is 1.05×10-7, which is slightly higher than others. Taichung County and Nantou County come in second and third, followed with Taichung City, Miaoli County and Yunlin County, which are all below 10-8.
Currently, the dioxin emission standard for stationary pollution sources is effective and Bureau of the Environmental Inspection has carried out relevant inspection work. This study assists to supervise sampling and analysis and review of the reports. During the project period, 26 plants-times supervising were completed and the environmental protection sheets were summarized as 2009 data, a total of 82 plants-times inspection and 106 plants-times periodical analysis were completed. There are 7 plants-times did not meet the emission standard, total failing rate is 4%. Since the beginning of 2010, 40 plants-times inspections plus analysis and 115plants-times periodical analysis were completed. There are 2 plants-times did not meet the emission standard, total failing rate is 1%.