| 摘要: | 本論文主要研究目的為運用生物動力及動態學模式，探討重金屬銅對吳郭魚 (Oreochromis mossambicus) 之慢性毒及魚體的生態生理反應。本研究主要進行兩部分實驗室實驗，(一) 14天之生物累積實驗，分析暴露於 0.1, 0.2, 0.3, 0.6 μg mL-1銅溶液下，吳郭魚體內器官對銅之累積變化量，並以一階單區塊累積模式擬合暴露試驗資料推估各器官之吸收速率常數 (uptake rate constant, k1)、排除速率常數 (elimination rate constant, k2) 及生物濃縮因子 (bioconcentratoion factor, BCF)；以及 (二) 28 天之慢性毒成長實驗，觀察生存於 0.1, 0.2, 0.3, 0.6 μg mL-1 之不同銅濃度環境，對吳郭魚成長之抑制反應，並由試驗成長數據，推估銅對吳郭魚造成 50 % 成長抑制之效應濃度 (EC50)。實驗結果指出，暴露於 0.1μg mL-1, 0.2 μg mL-1, 0.3 μg mL-1 及 0.6 μg mL-1銅濃度下 14 天之吳郭魚，各器官及組織內銅濃度及BCF值大小順序皆為肝臟>消化道>腎臟>鰓>肌肉，第7, 14, 21, 28 天的EC50值，分別為 0.257, 0.28, 0.269, 0.271 μg mL-1。利用各器官之銅累積數據及成長抑制資料，結合生物動力及動態學概念，利用損害評估模式 (damage assessment model, DAM) 探討吳郭魚各器官內銅累積之損傷修復情形，發現以生物體內濃度與時間之曲線下面積 (area under the curve, AUC) 取代原來單一時間點的體內濃度，能夠更有效地將損害評估模式應用於慢性毒研究中，說明生物體內器官在慢性暴露下之生理調節反應。本研究結果顯示，消化道及肝臟可作為進行銅慢性毒研究時之主要模式標的器官。本研究指出吳郭魚暴露於不同濃度銅水域時，吸收與累積能力變化及體內代謝調節反應，可提供日後吳郭魚或其它淡水魚對銅之慢性毒理研究及環境水質標準與監測之參考。
The purpose of this thesis is to assess the biokinetic (BK) and biodynamic (BD) modeling approach to chronic copper (Cu) toxicity and ecophysiological response of tilapia (Oreochromis mossambicus). We assessed the chronic toxicity that caused ecophysiological response of bioaccumulation concentrations and growth inhibition on tilapia following exposure to 0.1, 0.2, 0.3, 0.6 μg mL-1 of water-borne copper in laboratory. We conducted a 14-day exposure experiment to obtain BK parameters of uptake rate constant (k1), elimination rate constant (k2), and bioconcentration factor (BCF). The order of organ specific copper concentrations and BCF in selected organs and tissue are liver>alimentary canal>kidney>gill>muscle. Results of chronic growth toxicity assay showed that the specific growth rates (kg) are negatively correlated to waterborne Cu concentration, and EC50 (t) values in 7, 14, 21, 28 days are 0.257, 0.28, 0.269, 0.271 μg mL-1, respectively. We applied the damage assessment model (DAM) to depict the time course of toxicity and ecophysiological processes of tissue damage and recovery. We suggested that the area under the curve (AUC) was a great dose matrix for the DAM to describe the temporal trend of chronic toxicity. Alimentary canal and liver could be the sensitive target organ for assessing chronic copper toxicity. Results of this study can improve the understanding of chronic toxicities in tilapia and provide a reference for protecting the environment and aquaculture ecosystems. |
