| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 100 === The main purpose of the study was to understand the effects of ammonia in surface water on the acute toxicity of fish. River, discharged, feeding, potable water were used. When the concentration of ammonia was 25 mg/L ,the acute toxicity of ammonia is similar to that when the concentration of ammonia were 3 and 10 mg/L. The significant toxicity was observed when the concentration of ammonia was 75 mg/L, at which many fishes were dead. Ammonia and residual chlorine may form chloroamine; thus, even at low concentration, acute toxicity of ammonia may be enhanced and as ammonia reached 75 mg/L, TUa > 1.43. Biological treatment is commonly used to remove ammonia, which may transform ammonia into less toxic compounds. Therefore, it was found that the toxicity of ammonia may be limited in discharged wastewater due to the presence of nitrobacter. Because of the size, viability, and toxic pathway, organisms have different resistivity to toxic compounds. Therefore, selection of test organism should be assessed carefully. Also, environmental factors seemed to increase the death rate, and thus, affecting TUa
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