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2011- Monitoring and management of dioxin and heavy metal in Kaohsiung city

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This project investigated the emission of dioxin and heavy metal sampled from stationary sources in Kaohsiung city. Major works included the emission source sampling of dioxin and heavy metals, the emission source inquiry of dioxin, the analyses of ambient environment (air‚ leaves and soil), risk assessment, and technology transfer. For the emission source inquiry of dioxin, most factories were corresponded to the regulation. However, differential pressure gage of bag filter for Southern District MSWI was unnormal on December. The problems for Kaohsiung city mortuary services office - 1st crematorium were no sampling-platform load certificate, lower than 20 meters stack height, no hand sampling plan and report, and no record the operating conditions of bag filter. The mean total PCDD/Fs concentrations of stationary sources MSWI-D and CEM-D were 0.523 and 0.646 ng I-TEQ/Nm3, respectively. The values are higher than the regulation limit of Taiwan EPA. The emissions of PCDD/Fs from other emission sources are lower than the regulation limit of Taiwan EPA. The estimated total annual emission of PCDD/Fs from these emission sources in Kaohsiung city was 5.90 g I-TEQ/yr (large-scale MSWIs, 7.02%; small-scale MSWIs, 0.00266%; industrial waste incinerators, 0.575%; medical waste incinerators, 0.0328%; coke oven planes, 1.30%; cement kilns, 2.61%; sinter planes, 76.8%; RHF, 0.156%; electricfurnaces, crematorium 9.78%; cremation, 0.349%; boiler electricity generation, 0.0507%; secondary aluminum smelters, 0.925%; secondary zinc smelters, 0.0549%; secondary copper smelters, 0.309%). The existing emission sources of heavy metals were surveyed, including 4 MSWIs, 6 small-scale MSWIs, 1 medical waste incinerator, 1 boiler, and 1 soil heat-desorption incinerator. The emissions of heavy metals from 13 emission sources are lower than the regulation limit of Taiwan EPA. The total PCDD/F concentrations of ambient air, leaves and soil were 0.0252~0.0613 pg I-TEQ/Nm3, 1.74~3.54 ng I-TEQ/kg and 0.142~3.56 ng I-TEQ/kg, respectively. The mean PCDD/F concentrations of ambient air, leaves and soil were 0.0467 pg I-TEQ/Nm3, 2.56 ng I-TEQ/kg and 1.91 ng I-TEQ/kg, respectively. The dominant contributions of PCDD/Fs concentration in Siaogang district were electricfurnaces and sinter planes. AERMOD model was applied to evaluate the concentration of dioxins and their dry and wet deposition in the environment, and then Human Health Risk Assessment Protocol (HHRAP) model was used to calculate the concentration of each environmental media and the amount of exposure in each pathway. By integrating these two models, it is estimated that risk contribution of dioxins and heavy metals emitted from stationary emission sources sampled and monitored in this project. Dioxin and arsenic are the main contaminants which contribute to the cancer and non-cancer risk respectively. The cancer risk values are ranged from 2.05E-10 to 5.22E-08, and the first five affected areas are located in Siaogan, Sanmin, Lingya, Sinsing, and Cianjhen Districts. Moreover, the non-cancer risk values are ranged from 2.26E-5 to 3.12E-03, and the first five affected areas are located in Sanmin, Lingya, Sinsing, Siaogan, and Cianjin Districts. Nanzih District is the area accepting least cancer and non-cancer risk.
Keyword
PCDD/Fs, heavy metal, stack, emission factor, risk assessment
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