太陽能光電廢水急毒性及遺傳毒性分析研究

Abstract

本研究有鑑於太陽能光電業之發展迅速，其CdS製程所放流水排放可能會增加對環境之危害風險，因此欲建立生物急毒性評估－水蚤靜水式試驗(Daphnia magna immobility test)及遺傳毒性評估－SOS/umu試驗兩種毒性評估之方法，來檢測CdS製程廢水及處理後之放流水的毒性。本研究自行配置模擬實場之廢水，探討化學品之單一及綜合毒性，找出可能的毒性來源。 實驗結果顯示水蚤(D. magna)對於氨、硫脲及鎘之EC50為83.25、23.05和0.067 mg/L，TUa為5.42、3.04及1.17，急毒性風險為極毒性(very toxic)；混合含氨、硫脲及鎘之廢水之TUa上升至12.33-21.06，顯示出CdS製程之放流水具生物急毒性風險。針對遺傳毒性試驗皆無顯著反應，推估可能原因為誘導DNA變異的情形不大相同。以Fenton氧化法處理硫脲，對此氧化處理之廢水做相關之毒性評估，結果顯示經Fenton氧化處理後，其TUa上升2.5倍，遺傳毒性效應也有上升的趨勢，顯示出氧化處理對硫脲的毒性有負面的影響。本研究顯示出利用水蚤(D. magna)可敏感而有效的檢出CdS製程廢水之毒性，而SOS/umu試驗則對其敏感度較低。

As the development of photovoltaic industry is escalating, many environmental issues have emerged dramatically as well. In 2010, the Taiwan EPA set a standard for the discharge of the wastewater from photovoltaic industry. Since then many PV manufacturers have to find ways to deal with the problem. Therefore, both acute toxicity and genotoxicity of the CdS manufacturing wastewater were examined.In this study, two methods for testing acute and chronic toxicity were conducted, namely, Daphnia magna immobility test and SOS/umu test. Both were employed to detect the wastewater and effluent of CdS manufacturing process in CIGS thin film solar cell. The samples were prepared in the lab to simulate the real concentrations in the factory and to represent the single and combined toxicity. In single toxicity, the EC50 is 83.25, 23.05 and 0.067 mg/L for ammonia, thiourea and cadmium on D. magna, respectively, and TUa is 5.42、3.04 and 1.17, meaning that the toxicity risks is ‘’very toxic’’. For combined toxicity, the TUa increased to 12.3-21.06 depending upon the combination, and had probability to exceed the level. For genotoxicity assessment, no significant response was observed. After treated the thiourea by Fenton oxidation process showed increased toxicity response on both test D. magna and and SOS/umu test. In this research, Daphnia magna immobility test had high sensitivity for CdS manufacturing wastewater, but not SOS/umu test.