銅離子影響磷酸三(2-正丁氧乙基)酯的水蚤生物累積性與毒性之研究

Abstract

隨著電子產品汰換速度加快，電子廢棄物(electronic waste, e-waste)的總量逐漸增加，其成分複雜，包含金屬(如銅(Cu(II))和阻燃劑(如磷酸三(2-正丁氧乙基(tris(2-butoxyethyl) phosphate, TBEP))等皆是常見的組成物質。然e-waste回收處理技術不甚成熟，過程中易流入環境並造成危害，因此e-waste的污染問題引起高度的關注；此外，即便這些毒性物質於環境中含量不高，仍應考量其在生物體內長期累積以及與其他物質產生混合毒性效應。本研究選用水蚤做為試驗生物，以21天慢毒性試驗和3天累積性試驗評估TBEP對水蚤的生殖抑制性和生物累積情形，進一步探討其和Cu(II)共存狀況下對水蚤毒性效應之影響。TBEP對於水蚤21日生殖抑制濃度(inhibition concentration, IC25)為1.3 mg/L，而Cu(II)對於水蚤具有較強烈的生殖抑制毒性。然當TBEP和Cu(II)共存時，對水蚤第一胎生產天數和子代數目呈現毒性降低之情形，即混合後反而使第一胎產出時間提前，子代數目上升。在累積性試驗方面，TBEP為低度累積性，混合後反而增加了生物濃縮係數(Bioconcentration factor, BCF)，即其生物累積性上升。綜合上述結果可以發現，TBEP和Cu(II)混合後會降低毒性效應並增加其生物累積性。

Electronic waste (e-waste), which is released from the discard of electronic products, is getting much concern from scientists and environmentalists because of its complex compositions, including copper (Cu(II)) and Tris (2-butoxyethyl) phosphate (TBEP)-a kind of flame retardants. TBEP is one of the endocrine disrupter, interfering hormone like estradiol and testosterone; Cu(II) may cause liver cirrhosis. Both of them infect the health of organisms. However, few studies have investigated the relationship between Cu(II) and TBEP and their impacts on aquatic organism. This work was thus carried out to investigate the co-effect of TBEP and Cu(II) on the chronic toxicity and bioaccumulation using Daphnia magna. The 21-days chronic toxicity and 3-days accumulation tests have been conducted to evaluate long-term effects and the combined toxicity effects of TBEP and Cu(II) on Daphnia magna, which is one of most commonly used test organism. Results showed that the 25% inhibition concentration (IC25) of TBEP was 1.3 mg/L for D. magna reproduction in the individual toxicity. TBEP and Cu(II) concentrations in the body of D. magna were higher than in the exposure solution, thus indicating bioaccumulation do happen in D. magna for the accumulation tests. The combined toxicity test revealed that the presence of Cu(II) resulted in antagonism on the reproduction inhibition, suggesting that the joint toxic test of Cu(II) and TBEP negatively affect the toxicity. Under the co-exposure of TBEP and Cu(II), the bioconcentration factor increased, indicating that the bioaccumulation increased as Cu(II) added.