Black Carbons Dominate Sorption and Desorption of Polycyclic Aromatic Hydrocarbons and Endocrine Disrupting Chemicals in Lake Sediments : 호소 퇴적물 내 다환방향족탄화수소(PAHs)와 내분비계 교란물질의(EDCs) 흡착 및 탈착

국문 초록 (Abstract)

PAHs와 EDCs는 인간의 건강과 생태계에 미치는 잠정적인 영향 때문에 환경오염으로 나타내어진다. 퇴적물에서 복잡한 PAHs와 EDCs의 이동과 거동 그리고 흡착/탈착 기작을 완전히 이해하기 위한 시도는, 최근 수년간 주목받았음에도 불구하고 여전히 도전중에 있다. BC(black carbon)은 soot, chars, charcoal, coke, cool, kerogen을 포함하는 탄소질의 물질들로 정의된다. 퇴적물 시스템의 복잡성, 표준화, 검증의 부족과 BC 의 불균일성과 다양한 origins는 흡착과 탈착 공정을 완전히 이해하기 어렵게 만드는 요인이다.
본 연구에서는 여러 가지의 호수 퇴적물과 black carbon에서 PAHs와 EDCs의 흡착/탈착 특성을 조사하였다. 습식 화학적 산화(Wet chemical oxidation)는 Wet chemical oxidation 은 BC의 분리와 정량을 위해 사용되었다. 회분식 흡착과 탈착실험은 14C-labeled PAHs와 EDCs를 이용하여 수행하였다. Freundlich, solubility-normalized Freundlich (SNFM), Langmuir, Polanyi-Dubinin-Manes (PDM), Polanyi-Manes (PM), Dubinin- Radushkevich (DR) and Dubinin-Astakhov (DA) 모델과 같은 몇몇의 흡착 모델을 흡착등온선을 분석하기 위해 사용되었다. 게다가 이상탈착 모델(biphasic desorption model)을 탈착등온선을 분석하기 위해 사용하였다.
호소 퇴적물로부터 분리된 black carbons은 원퇴적물(original sediments)보다 좀더 높은 분배계수(distribution coefficient), 흡착용량(sorption capacity) 그리고 비선형성(nonlinearity)을 보여준다. 높은 농도와 낮은 농도에서 PAHs의 흡착메카니즘은 다양하였다. Freundlich와 solubility-normalized Freundlich model 분석결과 BCs의 Freundlich coefficients가 처리되지 않은 침전물의 BCs보다 높게 니타났다. Langmuir model이 흡착등온선(sorption isotherms)을 가장 적절하게 모사하였다. 흡착/탈착 등온선에 대한 aging (또는 contact time) 의 영향과 PAHs의 탈착저항성을 조사하였다. Aging time이 증가할수록 PAHs의 흡착 용량(sorption capacity)도 증가되었다. 더욱이 탈착저항성은 contact time과 같이 증가되었다. 침전물에서 BCs와, PAHs와 EDCs의 흡착/탈착 연구는 BC의 개선된 분리, 생물학적 이용성의 평가와 흡착/탈착 저항성의 조사에 활용될 수 있을 것이다.

다국어 초록 (Multilingual Abstract)

Polycyclic aromatic hydrocarbons (PAHs) and endocrine disrupting chemicals (EDCs) are present as environmental pollutants due to their potential impacts on ecosystems and human health. To fully understand the complex fate and transport of PAHs and EDCs, especially sorption/desorption behaviors in sediment system is still challenging despite it has received attention over the years. Black carbon (BC) is defined as carbonaceous materials including soot, chars, charcoal, coke as well as coal and kerogen. Except for the complexity of sediment system, the lack of standardization and identification in definition as well as heterogeneity and diverse origins of BC are the factors contributing to difficulties in fully understanding sorption and desorption processes in BC.
Sorption and desorption characteristics of PAHs and EDCs in various lake sediments and black carbons were investigated in this study. A wet chemical oxidation method was used for isolation and quantification of BC. Batch sorption and desorption experiments were conducted using 14C-labeled PAHs and EDCs. Several sorption models such as Freundlich, solubility-normalized Freundlich (SNFM), Langmuir, Polanyi-Dubinin-Manes (PDM), Polanyi- Manes (PM), Dubinin-Radushkevich (DR) and Dubinin-Astakhov (DA) models were used to analyze sorption isotherm data. In addition, biphasic desorption model were used to analyze desorption isotherm data.
Black carbons isolated from lake-sediments show higher distribution coefficient, sorption capacity, and nonlinearity than the original sediments. Sorption mechanisms of PAHs at high concentration and low concentrations were widely different. Freundlich and solubility-normalized Freundlich model analyses indicate that the Freundlich coefficients of BCs were higher than these of original sediments. Langmuir model was the best fitting the data in sorption isotherms. Effect of aging (or contact time) on sorption and desorption isotherms and desorption-resistance of PAHs were also investigated. As aging time increased, the sorption capacity of PAHs increased. Moreover, desorption-resistance was also increasing with the contact time.
Sorption and desorption studies of PAHs and EDCs in sediments and BCs may develop an improved isolation of BC, investigation of sorption and desorption mechanisms and assessment of bioavailability.

목차 (Table of Contents)

• 1. INTRODUCTION 1
• 1.1 Fate and Transport of Environmental Pollutants in Sediments 1
• 1.2 Polycyclic Aromatic Hydrocarbons 2
• 1.3 Endocrine Disrupting Chemicals 9
• 1.4 Sorption and Desorption of Hydrophobic Organic Compounds to Sediments 12
• 1.5 Black Carbon 13
• 1.6 Research Purpose 15
• 2. LITERATURE REVIEW 17
• 2.1 Introduction 17
• 2.2 Black Carbon in Sediment 17
• 2.3 Sorption and Desorption 27
• 2.4 Sorption/Desorption and Biodegradation 41
• 3. MATERIALS AND METHODS 43
• 3.1 Introduction 43
• 3.2 Sediment Sources 44
• 3.3 Isolation and Quantification of Black Carbon 44
• 3.4 Sorbent Characterization 47
• 3.5 Chemicals 50
• 3.6 Measurement of Aqueous Phase Concentration 52
• 3.7 Sorption and Desorption Experiment 53
• 3.8 Biodegradation Experiment 59
• 4. RESULT AND DISCUSSION 65
• 4.1 Introduction 65
• 4.2 Sorbent Characteristics 65
• 4.3 Sorption and Desorption of PAHs in Various Sorbents 82
• 4.4 Sorption and Desorption of EDCs in various Sorbents 126
• 5. CONCLUSIONS 134
• 6. REFERENCE 137