多氯聯苯(Polychlorinated biphenyls,
PCBs)為包含209 種同類物的人工合成物,具
親脂性,進入環境後會累積在食物鏈中,同
時會造成各種毒性,可能是導致鯨豚發生疾
病及擱淺的原因之一。鯨豚屬於哺乳動物,
生活史長,且身為海洋食物鏈的高級消費
者,適合做為海洋持久性有機物污染的生物
指標。本研究首先建立適合分析鯨脂內PCBs
的方法,然後收集台灣沿海擱淺與流刺網誤
捕鯨豚之鯨脂樣本進行19 種PCBs 同類物分
析,並收集病材做疾病探討。從2000 年至2001
年共收集73 隻13 種鯨豚之37 隻雄性及36
隻雌性的鯨脂樣本,包含擱淺19 隻及誤捕54
隻。總濃度範圍從花紋海豚的235 ng/g 脂重
到糙齒海豚的33,734 ng/g 脂重。不同鯨豚種
類成熟雄性鯨脂內PCBs 濃度由高到低分別
是糙齒海豚、小虎鯨、瓶鼻海豚、弗氏海豚、
花紋海豚及熱帶斑海豚;此外,擱淺組濃度
極顯著高於誤捕組,可能和擱淺個體普遍呈
消瘦且身體狀況極差有關,但PCBs 濃度與疾
病之間的關係仍須做更進一步的評估。成熟
雄性個體濃度顯著大於未成熟雄性個體,而
不同成熟度的雌性個體濃度變異度很大,可
能和PCBs 會隨懷孕及泌乳傳給下一代有
關。所選取19 種同類物中,以5 到7 個氯的
同類物含量為主,其中又以PCB153 含量最
多,佔PCBs 總量的20 到30%。另外以TEQs
(2,3,7,8-TCDD equivalent quantity) 評估PCBs
毒性,範圍由露脊鼠海豚的2.7 pg/g 脂重到糙
齒海豚的7,967 pg/g 脂重。毒性主要來自
PCB126,其次為PCB118 及PCB156。與其他
研究報告結果比較,台灣沿海鯨豚體內PCBs
濃度相對較低,與熱帶地區的菲律賓、印尼、
南非及澳洲結果類似。Polychlorinated biphenyls (PCBs) are
highly persistent, bioaccumulative, and toxic
contaminants that had been suspected to be part
of the reasons for cetaceanâs stranding and
diseases. Total of 73 blubber samples of 13
cetacean species from stranded or accidentally
caught were collected during year 2000 to 2001.
Total concentrations of 19 PCBs congeners were
between 230 ng/g lipid weight of Rissoâs
dolphin to 33,734 ng/g lipid weight of
rough-toothed dolphin.
The most abundant congener was PCB153 in all
samples and penta to hepta chlorobiphenyls
were the predominant PCB congeners. The ratio
of PCB153 to total 19 PCBs congeners was very
consistent between 20 to 30%. The
2,3,7,8-tetrachlorodibenzo- p-dioxin equivalents
(TEQs) were from 2.7 pg/g lipid weight of
finless porpoise to 7,967 pg/g lipid weight of
rough-toothed dolphin. One of the non- ortho
congener, PCB126, has the most weigh.
PCB118 and PCB156, mono- ortho congeners,
were the second contributors to TEQs. PCBs
concentrations and TEQs were higher in mature
male cetaceans than in immature male cetaceans
but were inconsistent in female cetaceans for the
transferring of PCBs from mother cetacean to
their offsprings by gestation and lactation. In
this study, cetaceans from Taiwan waters have a
relative lower PCBs concentrations and TEQs
comparing to other high latitude waters