博士 / 國立成功大學 / 環境工程學系碩博士班 / 98 / Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDD/Fs) are proven as carcinogenic and mutagenic compounds, and are recognized as poisons of the century. In this study, accumulation of PCDD/Fs and dioxin-like polychlorinated biphenyls (DL-PCBs) between environmental media and fish were investigated. In addition, the dietary intake of PCDD/Fs for Taiwanese was discussed.
The first part of the study includes the PCDD/F and DL-PCB levels in environmental media (water, sediment, and feed) and in farmed fish of different age. To observe the accumulation of PCDD/Fs and DL-PCBs in farmed fish, tissue samples of hatchling, 2-month, 15-month, 24-month, and 36-month-old were collected, and the samples of all the environmental media were taken right after each time fish samples were collected.
PCDD/F levels in a total of 25 food items in Taiwan and the PCDD/F intake of Taiwanese were surveyed in the second part of this study. PCDD/F intake of some special population such as duck farmer who may ingest high quantity of contaminated duck eggs were also determined.
The results of the first part showed that PCDD/F and DL-PCB levels in water and sediment from fish farm were lower than those from natural environment such as rivers and lakes. The discharge of farm water and rearrangement of farm land each time fish were harvested may result in low levels of PCDD/Fs and DL-PCBs in water and sediment samples.
In Environmental medium, PCDD/F levels were all higher than DL-PCB levels. However, DL-PCBs were found to contribute more to the TEQ than PCDD/Fs were in all the fish samples. Both PCDD/Fs and DL-PCBs concentrations rose with the period that groupers were raised. The results in this study conclude that PCDD/Fs and DL-PCBs could accumulate in fish tissues, and diet is the main source of the accumulations.
In the second part of this study, it was observed that shellfish and saltwater fish possessed the highest PCDD/Fs levels, 9.82 and 3.60 pg WHO-TEQ/g, respectively, on the lipid basis. The dietary intakes of humans at ages of 12-18, 19-64, and over 65 were determined. The estimated intake were between 21.8 (female teenagers) and 37.6 pg (male seniors) WHO-TEQ/day; the levels varied with the dietary habits. The PCDD/F intakes for all human groups are far below the tolerable limit of 70 pg WHO-TEQ/Kg b.w./month. In addition, the daily PCDD/F intake levels for duck farmers consuming average and large amounts of PCDD/F contaminated duck eggs were examined. The result shows that consuming more than one duck egg with level higher than 10 pg WHO-TEQ/g lipid of PCDD/Fs per day could lead to a PCDD/F intake level higher than the tolerable limit. However, for normal population, there is little risk to ingest intolerable amount of PCDD/Fs because of intake of contaminated duck eggs.
| Identifer | oai:union.ndltd.org:TW/098NCKU5515001 |
| Date | January 2009 |
| Creators | I-Ching Wang, 王怡靜 |
| Contributors | Wen-Jhy Lee, Yee-Lin Wu, 李文智, 吳義林 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 82 |
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