攝食對台灣西南沿海高蹺?A汞暴露之影響

The Effect of Ingestion on Mercury Exposure to The Black-winged Stilt ( Himantopus himantopus ) in Southwestern Taiwan

何英妮(Ying-Ni Ho)

指導教授 ： 洪慶宜

長榮大學/健康科學學院/職業安全與衛生研究所/碩士(2007年)

摘要

有鑒於國內針對水鳥體內環境毒物蓄積的研究很少，因此本研究利用高蹺?A（Himantopus himantopus）繁殖期間進行採樣，藉以了解台鹼安順廠於1964到1982年產製農藥期間污染物擴散，對台南市四草野生動物保護區內及周遭造成的生態風險。本研究以高蹺?A鳥蛋、肌肉、肝臟及羽毛等之總汞的含量作為暴露評估基準，並以北門濕地的鳥蛋進行對照。本研究亦針對兩地高蹺?A主要攝食的5個食物種類(牙蟲、流紋蜷、?鱆瞗B大肚魚和吳郭魚)及環境樣本(底泥)也一併進行總汞分析，以釐清高蹺?A生物累積現象與食物鏈傳遞與環境的關係。
研究結果顯示，四草保護區與北門濕地收集到的高蹺?A鳥蛋所分析出的總汞含量分別為0.227 ± 0.137 ppm 及0.188 ± 0.068 ppm，經由統計檢定顯示地點與高蹺?A鳥蛋中汞含量沒有顯著差異(P＝0.21)。高蹺?A主要食物汞含量分析結果顯示，兩地區牙蟲、流紋蜷及?鱆磛S有顯著的差異(P分別為0.284、0.191及0.09)；而四草保護區大肚魚及吳郭魚顯著較高(P＜0.05)。四草保護區與北門濕地底泥總汞含量平均各為1.455 ± 1.668 ppm及0.010 ± 0.011 ppm，統計檢定顯示四草保護區底泥總汞明顯較高(P＜0.05)。分析並比較高蹺?A肌肉、羽毛及肝臟總汞含量，肌肉汞含量與肝臟汞含量具顯著相關(r= 0.95)；成鳥各檢體總汞含量皆高於幼鳥。
本研究綜合高蹺?A食物鏈物種汞含量、體重及攝食比例(翁義聰等，2007)資料，經Monte Carlo simulation分析經攝食途徑各汞暴露來源機率，顯示高蹺?A經攝食途徑暴露汞的風險於四草保護區內捕食將會高於北門濕地。然可能因高蹺?A遷移範圍較廣，四草及北門皆屬同一捕食區域，致使兩地高蹺?A鳥蛋總汞含量未呈顯著差異。

關鍵字

汞暴露 ； 高蹺?A ； 食物鏈傳遞 ； 生態風險

並列摘要

Only few attempts have so far been made at the bioaccumulation of environmental toxicants in water birds. The present study investigated the risk of mercury exposure of black-winged stilt, Himantopus himantopus, in the Sihcao Wildlife Reservation Area and its vicinities during the breeding season of the bird. The past releases of pentachlorophenol, dioxin, and mercury during pesticide manufacturing period from 1964 to 1982 by Taiwan Alkali Corporation An-Shun Plant, which adjacent to the Sihcao Wildlife Reservation Area, might pose an ecological risk to the wildlife. Mercury contents in egg, muscle, liver, and feather of black-winged stilt were estimated to assess the levels of exposure. Biological samples taken from Beimen wetland, a related pristine area without the historical contamination, were served for comparison. Five major preys of black-winged stilt (Hydrophilidae, Thiaridae, Gobiidae, Poeciliidae, and Cichilidae) as well as sediments from Sihcao and Beimen were analyzed for their mercury contents to estimate the influence of trophic transfer and contaminated site to the bioaccumulation of mercury in Himantopus himantopus.
Mercury concentrations in eggs of black-winged stilts from Sihcao and Beimen were 0.227±0.137 ppm and 0.188±0.068 ppm, respectively. Statistical analysis showed an insignificant difference among the two (P＝0.206). There were also insignificant differences in mercury contents of Hydrophilidae, Thiaridae, and Gobiidae among the two locations (P＝0.284, 0.191, and 0.09, respectively). Poeciliidae and Cichilidae caught in Sihaco, however, showed significantly higher in mercury contents than those from Beimen (P<0.05). Mercury concentrations in sediments from Sihcao (1.455±1.668 ppm) were significantly higher than those from Beimen (0.010±0.011 ppm)(P＜0.05). Further analyses of mercury concentrations in muscles, feathers, and livers of black-winged stilts showed a better correlation between muscular mercury and liver mercury (r= 0.95) and a generally age-dependent tendency with higher mercury contents in samples of adult birds than those of juvenile ones.
The possibilities of mercury intakes of black-winged stilts from individual food sources were estimated by Monte Carlo simulations of mercury contents, body weights, and ingested ratio of the five major preys. The result indicated a higher possibility of mercury exposure of the water birds through trophic transfer upon preying at Sihcao Wildlife Reservation Area. However, probably due to the long migratory distances and large predatory territory of the water birds, the eggs from Shicao and Beimen had the same level of mercury content.

並列關鍵字

mercury exposure ； Himantopus himantopus ； trophic transfer ； ecological risk

參考文獻

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