S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Civil & Environmental Engineering (건설환경공학부) Theses (Master's Degree_건설환경공학부)
Proposed Method for Controlling Turbid Particles in Solid-Phase Bioluminescent Toxicity Measurement
고형 시료의 탁도 제어에 따른 생태독성학적 평가방법의 산정법 제안
- 공과대학 건설환경공학부
- Issue Date
- 서울대학교 대학원
- 학위논문 (석사)-- 서울대학교 대학원 : 건설환경공학부, 2015. 8. 박준범.
- In the recent half century, numerous methods have been developed to assess ecological toxicity. However, the presence of solid-particle turbidity sometimes causes such tests to end with questionable results. Many researchers focused on controlling this arbitrary turbidity effect when using the Microtox® Solid-Phase toxicity system, but there is not yet a standard method. In this study, I examined four solid-phase sample test methods recommended in the Microtox® manual, or proposed from the literature, and compared the existing methods with the proposed method (c-BSPT, centrifuged-BSPT). Four existing methods use the following strategies to control turbid particles: complete separation of liquid and solid using 0.45-μm filtration before contacting solid samples and bacteria, natural settlement, moderate separation of large particles using coarser-pore-size filtration, and exclusion of light loss in the toxicity calculation caused by turbidity after full disturbance of samples. The proposed method uses moderate centrifugation to separate out the heavier soil particles from the lighter bacteria after direct contact between them. Among the solid-phase methods tested, in which the bacteria and solid particles were in direct contact (i.e., three existing methods and the newly proposed one, c-BSPT), no single method could be recommended as optimal for samples over a range of turbidity. Instead, a simple screening strategy for selecting a sample-dependent solid-phase test method was suggested, depending on the turbidity of the solid suspension. The results of this study highlight the importance of considering solid particles, and the necessity for optimal selection of test method to reduce errors in the measurement of solid-phase toxicity.