半導體廢水主要毒性物質對水蚤及斑馬魚胚胎混合毒性之研究

Abstract

半導體製造業為台灣重要科技產業，其廢水排放量大且因製造過程使用多種劇毒化學品使放流水成分複雜，即使其中毒性物質含量均低，但有考量混合毒性效應對各生物影響之必要。因此本研究以人工配製之模擬廢水，使用大水蚤(Daphnia magna)及斑馬魚(Danio renio)胚胎，從不同受測生物及觀察終點探討半導體廢水中代表性毒性物質氨氮、氫氧化四甲基銨(TMAH)及銅之單一毒性及混合毒性。單一毒性試驗中，氨氮、TMAH及銅對水蚤無法移動率之半數效應濃度(EC50)分別為26.20 mg/L as N、1.02 mg/L、0.02 mg/L；而對斑馬魚幼魚致畸胎率EC50則為84.43 mg/L as N、460.53 mg/L、0.04 mg/L，銅對於兩生物都是三物質中毒性最強者。而混合毒性效應試驗結果中，含銅混合水樣對水蚤無法移動率均偏向拮抗效應，即銅降低其混合毒性，但斑馬魚幼魚致畸胎率卻呈現相反的效果，數據進行複迴歸分析結果亦符合此趨勢。本研究顯示混合毒性效應會因受測生物及觀察終點而異，且銅為半導體廢水中影響混合毒性效應趨勢的關鍵毒性物質。另外由幼魚畸胎型態的轉變及心跳率的異常顯示物質混合前後對生物毒性機制應有所不同，且混合後之毒性較單一物質更為強烈。

Semiconductor manufacturing industry is flourishing in Taiwan, which effluent is harmful to environment due to the existence of various substances, such as NH4+, TMAH and Cu(II). Although the amount of the individual substance in the effluent is low, the combined effects on aquatic organisms should be concerned. The aim of this study is to examine individual and combined toxicity of NH4+, TMAH and Cu(II) on Daphnia magna and zebrafish (Danio renio) embryos in the synthetic wastewater. For the individual toxicity, the EC50 of NH4+, TMAH and Cu(II) were 26.20 mg/L as N, 1.02 mg/L and 0.02 mg/L for Daphnia magna immobility, and 84.43 mg/L as N, 460.53 mg/L and 0.04 mg/L for zebrafish larvae malformation, respectively. It suggests that Cu(II) is the most toxic substance for the both organisms. For combined toxicity, the presence of Cu(II) resulted in antagonism on the immobility of Daphnia magna in all combinations. In contrast, the synergism was observed on malformation of the zebrafish larvae. The multiple regression analysis revealed that Cu(II) is the critical factor for determining the combined effects in the semiconductor wastewater. Besides, sublethal endpoints of zebrafish such as malformation types and abnormal heartbeat rates indicated that the toxicity is enhanced and the modes of toxicity were different in the combinations.