Title Page
ABSTRACT
국문 초록
PREFACE
Contents
NOMENCLATURE 22
CHAPTER 1. INTRODUCTION 26
1.1. Research Background 27
1.2. Research Objectives 31
CHAPTER 2. MATERIALS AND METHODS 33
2.1. Daphnia magna Culture 34
2.2. Preparation of Microplastic Fragments 36
2.3. Characterization of Microplastic Fragments 39
2.4. Toxicity Analyses 41
2.5. Bioconcentration Analyses 46
2.6. Phototactic Behavior Analysis 47
2.7. Oxidative Stress Analyses 48
2.8. Histopathological Analysis 50
2.9. Global DNA Methylation Analysis 52
2.10. Statistical Analyses 53
CHAPTER 3. COMPARISON OF INDIVIDUAL AND GROUP EXPOSURES OF MICROPLASTIC FRAGMENTS CONTAINING BENZOPHENONE-3 TO Daphnia magna 54
3.1. Effect of Individual and Group Exposures on Lethal Toxicity 55
3.2. Effect of Individual and Group Exposures on Sublethal Toxicity 58
3.3. Implications of This Study 62
CHAPTER 4. CHRONIC TOXICITY OF MICROPLASTIC FRAGMENTS CONTAINING BENZOPHENONE-3 IN Daphnia magna 65
4.1. Physicochemical Properties of Microplastic Fragments 66
4.2. Lethal Toxicity of Microplastic Fragments 71
4.3. Sublethal Toxicity of Microplastic Fragments 80
CHAPTER 5. TRANSGENERATIONAL TOXICITY OF MICROPLASTIC FRAGMENTS CONTAINING BENZOPHENONE-3 IN Daphnia magna 85
5.1. Physicochemical Properties of Microplastic Fragments 86
5.2. Chronic Toxicity of Microplastic Fragments in F0 Generation 91
5.3. Transgenerational Toxicity of Microplastic Fragments in F3 Generation 102
CHAPTER 6. CONCLUSIONS 109
REFERENCES 112
APPENDICES 138
A.1. Amount of Chemicals Contained in MP/BP-3 Fragments Used in This Study 138
A.2. Experimental Methods Conducted in This Study 139
Table 2.1. Median effective concentration (EC₅₀) and 95% confidence interval (CI) in the acute toxicity testing (48 h) of potassium dichromate to Daphnia magna 35
Table 2.2. Survival rate and the number of offspring per female in the chronic toxicity testing (21 d) of negative control (M4 medium) to Daphnia magna. 45
Table 3.1. Individual and group exposure in acute and chronic toxicity testing to daphnia within study. 64
Table 5.1. Histological alterations in the gut of Daphnia magna (F0 generation) exposed to polyethylene microplastic fragment (MP), BP-3 leachate from MP/BP-3 fragment (BP-3),... 95
Figure 1.1. Graphical abstract of this dissertation. 32
Figure 2.1. A schematic diagram for preparation of polyethylene microplastic fragments containing benzophenone-3 additive. 37
Figure 3.1. Daily survival of Daphnia magna for individual and group exposure to polyethylene microplastic fragments (MP) and MP fragments containing benzophenone-3... 57
Figure 3.2. Number of offspring per female Daphnia magna for individual and group exposure to M4 medium (control) for 21 days. Data are presented as mean and interquartile... 59
Figure 3.3. Number of offspring per female Daphnia magna for individual and group exposure to polyethylene microplastic fragments (MP), benzophenone-3 leachate from... 61
Figure 4.1. Field emission-scanning electron microscopy (FE-SEM) images of (a) microplastic (MP) fragments and (b) MP fragments containing benzophenone-3 additive... 67
Figure 4.2. Fourier-transform infrared spectra of polyethylene microplastic (MP) fragments, MP fragments containing benzophenone-3 (BP-3) (10.82 ± 1.20% w/w), and BP-3 additive. 69
Figure 4.3. Leaching kinetics of benzophenone-3 (BP-3) from microplastic (MP) fragments (5.0 mg L¯¹) of containing BP-3 additive (10.82 ± 1.20% w/w). The leaching solution was... 70
Figure 4.4. Acute toxicity (48 h) of polyethylene microplastic (MP) fragments (44.39 ± 11.16 µm) to neonate (<24 h) and juvenile (4 d-old) Daphnia magna. The exposure solution... 72
Figure 4.5. Survival rate of 4 d-old Daphnia magna exposed to benzophenone-3 (BP-3; 0.5 mg L¯¹), microplastic (MP) fragments (4.5 mg L¯¹), and MP fragments (5.0 mg L¯¹)... 74
Figure 4.6. Phototactic behavior of Daphnia magna after exposure to benzophenone-3 (BP- 3; 0.5 mg L¯¹), microplastic (MP) fragments (4.5 mg L¯¹), and MP fragments (5.0 mg L¯¹) ... 77
Figure 4.7. Bioconcentration of (a) microplastic (MP) fragments and (b) benzophenone-3 (BP- 3) in Daphnia magna after exposure to BP-3 (0.5 mg L¯¹), MP fragments (4.5 mg L¯¹), and MP fragments (5.0 mg L¯¹) containing BP-3 additive (10.82 ±... 79
Figure 4.8. (a) Body length of adult of Daphnia magna, (b) number of offspring per female, (c) embryonic development, and (d) body length of offspring after exposure to... 81
Figure 4.9. (a) Total antioxidant capacity (TAC) and (b) lipid peroxidation (LPO) in Daphnia magna after exposure to benzophenone-3 (BP-3; 0.5 mg L¯¹), microplastic (MP) fragments (4.5 mg L¯¹), and MP fragments (5.0 mg L¯¹) containing BP-... 84
Figure 5.1. Scanning electron microscopy images and Fourier transform-infrared spectra of polyethylene microplastic fragments (a) without and (b) with benzophenone-3 additive. 87
Figure 5.2. Size distribution of polyethylene microplastic fragments (a) without and (b) with benzophenone-3 additive. 88
Figure 5.3. Energy dispersive X-ray spectroscopy spectra and atomic percentage of polyethylene microplastic fragments (a) without and (b) with benzophenone-3 additive. 89
Figure 5.4. Daily survival of Daphnia magna (F0 generation) exposed to polyethylene microplastic fragment (MP), BP-3 leachate from MP/BP-3 fragment (BP-3), and MP... 92
Figure 5.5. Mean assessment value (MAV) of Daphnia magna (F0 generation) exposed to polyethylene microplastic fragment (MP), BP-3 leachate from MP/ BP-3 fragment (BP-3),... 93
Figure 5.6. Histopathology images of Daphnia magna (F0 generation) gut exposed to polyethylene microplastic fragment containing benzophenone-3 additive for 21 days.... 94
Figure 5.7. (a) Somatic growth rate and (b) number of offspring per female of Daphnia magna in F0 and F3 generations when exposed to polyethylene microplastic fragment (MP), BP-3 leachate from MP/BP-3 fragment (BP-3), and MP fragment... 97
Figure 5.8. Embryonic development of Daphnia magna in F0 and F3 generations when exposed to polyethylene microplastic fragment (MP), BP-3 leachate from MP/BP-3... 99
Figure 5.9. The dissolved concentrations of benzophenone-3 (BP-3) in M4 medium during the exposure of Daphnia magna (F0 generation) to BP-3 leachate from MP/BP-3 fragment... 101
Figure 5.10. Global DNA methylation of Daphnia magna over four generations (F0-F3) when exposed to polyethylene microplastic fragment (MP), BP-3 leachate from MP/BP-3... 104
Figure 5.11. Transgenerational effect on the number of offspring per female of Daphnia magna over four generations (F0-F3) when exposed to polyethylene microplastic fragment... 106
Figure 5.12. The population growth rate of Daphnia magna in F0 and F3 generations when exposed to polyethylene microplastic fragment (MP), BP-3 leachate from MP/BP-3... 108