碩士 / 國立交通大學 / 環境工程系所 / 102 / In semiconductor manufacturing processes nitrogenous substances are extensively used, resulting in production of very high nitrogen-containing wastewater. The high concentration of nitrogen-containing wastewater discharged to aquatic environment may cause eutrophication and toxicity. Although Taiwan EPA has regulated effluent standards for many pollutants, they are not sufficient to tell us if the discharge is toxic or not. Therefore, many countries are using animals to detect the toxicity of wastewater. Traditional toxicity tests usually use mortality as endpoint, but the sensitivity of this method is not adequate for low concentration pollutants. Zebrafish embryo assay has been regarded as a suitable alternative to the fish acute toxicity test which, apart from ethical reasons, provides very limited data (only LC50) and no ecotoxicological relevance. Due to transparency and extra-uterine development, zebrafish embryos can be directly observed the phenotypic changes during embryonic development. As a result, in this study zebrafish embryos were used to evaluate the toxicity and teratogenicity in nitrogen-containing wastewater. The purpose of this study is to examine the acute toxicity and developmental abnormalities in synthetic and real wastewater by using zebrafish embryos.
The results show the 96h-LC50 of ammonium chloride, sodium nitrate and tetramethylammonium hydroxide were 111 mg NH3-N/L, 1347.3 mg NO3--N/L and 68 mg N/L, respectively; the low observed effect concentration were 0.41 mg NH3-N/L, 0.51 mg NO3--N/L及0.1 mg N/L, respectively. The endpoints such as hatching rate, heart rate and body length significantly declined in these three nitrogenous solutions. Abnormalities including spinal curvature, pericardial edema and yolk sac edema were also observed in sequence in zebrafish larvae.
In real wastewater, the HF/CMP wastewater, acid-base wastewater and effluent from a semiconductor manufacturing factory were used. The mortality of zebrafish embryos in the acid-base wastewater and effluent was under 20% and 77% in HF/CMP wastewater in 96 hours. Although the mortality was low in the acid-base wastewater and effluent, the cumulative hatching rate, body length and especially heartbeat significantly decline. Abnormalities including spinal curvature, pericardial edema and yolk sac edema were also observed in real wastewater tests. The results indicate that the zebrafish embryos can be instrumental to detect the potential harm caused by wastewater on aquatic organisms at low concentrations. It suggests that embryo toxicity assay should be used to evaluate the toxicity of wastewater in the future.
| Identifer | oai:union.ndltd.org:TW/102NCTU5515012 |
| Date | January 2013 |
| Creators | Wu, Hui-Ju, 吳蕙如 |
| Contributors | Huang, Chih-Pin, Pan, Jill-Ruhsing, 黃志彬, 袁如馨 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 63 |
Page generated in 0.0092 seconds