Tang Wai Lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 199-220). / Abstracts in English and Chinese. / Abstract --- p.ii / 摘要 --- p.iv / Acknowledgements --- p.vi / Table of contents --- p.vii / List of Abbreviations --- p.xi / List of Tables --- p.xii / List of Figures --- p.xv / Chapter Chapter One --- Literature Review --- p.1 / Chapter 1.1 --- Marine pollution in Hong Kong --- p.1 / Chapter 1.2 --- Contamination of sediments --- p.3 / Chapter 1.2.1 --- Metals contamination in coastal sediments in Hong Kong --- p.4 / Chapter 1.2.2 --- Other contaminants in sediments --- p.7 / Chapter 1.3 --- Sediment toxicity assessment --- p.9 / Chapter 1.4 --- Fish as examples for the measurement of biological responses to contaminants --- p.9 / Chapter 1.5 --- Biomarkers for toxicity assessment --- p.11 / Chapter 1.5.1 --- Metallothionein (MT) --- p.11 / Chapter 1.5.2 --- Cytochrome P450 1A (CYP1A) --- p.13 / Chapter 1.5.3 --- Vitellogenin (Vtg) --- p.13 / Chapter 1.5.4 --- Enzyme biomarkers: Alanine transaminase (ALT); aspartate transaminase (AST) and creatine kinase (CK) --- p.14 / Chapter 1.5.5 --- DNA damage detected by the comet assay --- p.16 / Chapter 1.6 --- Multi biomarkers for sediment toxicity assessments --- p.16 / Chapter 1.7 --- Objectives --- p.16 / Chapter Chapter Two --- "Concentrations of Heavy Metals and Trace Organics in Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.18 / Chapter 2.1 --- Introduction --- p.18 / Chapter 2.2 --- Materials and Methods --- p.19 / Chapter 2.2.1 --- Sediment collection --- p.19 / Chapter 2.2.2 --- Treatment of sediment samples --- p.21 / Chapter 2.2.3 --- Acid wash of apparatus --- p.21 / Chapter 2.2.4 --- Acid digestion of sediment sample --- p.21 / Chapter 2.2.5 --- Sequential extraction of heavy metals in sediment samples --- p.22 / Chapter 2.2.6 --- Heavy metals measurement --- p.23 / Chapter 2.2.7 --- Trace organic measurement in sediments --- p.24 / Chapter 2.2.8 --- Statistical Analysis --- p.24 / Chapter 2.3 --- Results --- p.25 / Chapter 2.3.1 --- Concentrations of total Metals in sediments --- p.25 / Chapter 2.3.2 --- Speciation of metals in sediments --- p.27 / Chapter 2.3.3 --- Metal abundance in different fractions of sediment --- p.33 / Chapter 2.3.4 --- Concentrations of trace organic in sediments --- p.33 / Chapter 2.3.5 --- Results summary --- p.36 / Chapter 2.4 --- Discussion --- p.36 / Chapter 2.4.1 --- Comparison with international standards --- p.38 / Chapter 2.4.2 --- Comparison with international studies of coastal sediments --- p.39 / Chapter 2.4.3 --- Comparison of the present study with other studies concerning Hong Kong coastal sediments --- p.45 / Chapter Chapter Three --- "Heavy Metals Accumulation in Tissues of Tilapia Exposed to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour, and Lai Chi Wo" --- p.51 / Chapter 3.1 --- Introduction --- p.51 / Chapter 3.2 --- Materials and Methods --- p.52 / Chapter 3.2.1 --- Collection and treatment of coastal sediments --- p.52 / Chapter 3.2.2 --- Sediment exposure tests with Tilapia --- p.53 / Chapter 3.2.3 --- Dissection of fish samples --- p.54 / Chapter 3.2.4 --- Acid digestion of fish samples --- p.54 / Chapter 3.2.5 --- Statistical Analysis --- p.55 / Chapter 3.3 --- Results --- p.55 / Chapter 3.3.1 --- Metal accumulation --- p.55 / Chapter 3.3.2 --- "Dose, duration and source of sediments affecting metals uptake" --- p.95 / Chapter 3.3.3 --- Results summary --- p.99 / Chapter 3.4 --- Discussion --- p.99 / Chapter 3.4.1 --- Site comparison --- p.99 / Chapter 3.4.2 --- Comparison with other studies --- p.100 / Chapter 3.4.3 --- Safety limits --- p.112 / Chapter Chapter Four --- "Expression of Biomarker Genes (MT, CYP1 A, Vtg) in Tissues of Male Tilapia After Eexposure to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.115 / Chapter 4.1 --- Introduction --- p.115 / Chapter 4.2 --- Materials and Methods --- p.116 / Chapter 4.2.1 --- Sample collection --- p.116 / Chapter 4.2.2 --- Preparation of apparatus --- p.117 / Chapter 4.2.3 --- mRNA expression analysis --- p.117 / Chapter 4.2.3.1 --- Isolation of RNA --- p.117 / Chapter 4.2.3.2 --- Reverse transcription --- p.118 / Chapter 4.2.3.3 --- Real time PCR --- p.118 / Chapter 4.2.4 --- Vitellogenin (Vtg) --- p.120 / Chapter 4.2.5 --- Statistics analysis --- p.121 / Chapter 4.3 --- Results --- p.121 / Chapter 4.3.1 --- MT mRNA expression in tissues of male Tilapia exposed to sediments --- p.121 / Chapter 4.3.2 --- CYP1A mRNA expression in tissues of male Tilapia exposed to sediments --- p.129 / Chapter 4.3.3 --- Vtg expression in tissues of male Tilapia exposed to sediments --- p.137 / Chapter 4.3.4 --- Dose and time dependent relationships --- p.137 / Chapter 4.3.5 --- Results summary --- p.137 / Chapter 4.4 --- Discussion --- p.142 / Chapter 4.4.1 --- Correlation of MT and CYP1A expression with metals uptake in gills and liver --- p.142 / Chapter 4.4.2 --- MT as a biomarker of metals exposure --- p.144 / Chapter 4.4.3 --- CYP1A as a biomarker of trace organics exposure --- p.145 / Chapter 4.4.4 --- Real-time PCR --- p.147 / Chapter 4.4.5 --- Vtg as a biomarker of xenoestrogen exposure --- p.147 / Chapter Chapter Five --- "Expression of Enzyme Biomarkers (ALT, AST and CK) in Tissues of Male Tilapia After Exposure to Coastal Sediments Collected From Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.149 / Chapter 5.1 --- Introduction --- p.149 / Chapter 5.2 --- Materials and Methods --- p.150 / Chapter 5.2.1 --- Samples collection --- p.150 / Chapter 5.2.2 --- Alanine transaminase (ALT) and Aspartate transaminase (AST) --- p.151 / Chapter 5.2.3 --- Creatine kinase (CK) --- p.152 / Chapter 5.2.4 --- Statistical analysis --- p.153 / Chapter 5.3 --- Results --- p.153 / Chapter 5.3.1 --- ALT --- p.153 / Chapter 5.3.2 --- AST --- p.157 / Chapter 5.3.3 --- CK in gills --- p.157 / Chapter 5.3.4 --- CK in muscle --- p.164 / Chapter 5.3.5 --- "Dose, duration and source of sediments affecting metals uptake" --- p.164 / Chapter 5.3.6 --- Results summary --- p.169 / Chapter 5.4 --- Discussion --- p.169 / Chapter Chapter Six --- "DNA Damage in Liver of Male Tilapia After Exposure to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.174 / Chapter 6.1 --- Introduction --- p.174 / Chapter 6.2 --- Materials and Methods --- p.176 / Chapter 6.2.1 --- Samples collection --- p.176 / Chapter 6.2.2 --- Tissue Preparation --- p.176 / Chapter 6.2.3 --- Single Cell Gel Electrophoresis (Comet) Assay --- p.176 / Chapter 6.2.4 --- Image analysis --- p.177 / Chapter 6.2.5 --- Statistical analysis --- p.178 / Chapter 6.3 --- Results --- p.180 / Chapter 6.4 --- Discussion --- p.187 / Chapter Chapter Seven --- General Discussion and Conclusion --- p.190 / Chapter 7.1 --- General discussion --- p.190 / Chapter 7.2 --- Conclusion --- p.198 / References --- p.199 / Appendix --- p.221

Thesis (M.A.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 146-156). / Also available by subscription via World Wide Web / xxi, 156 leaves, bound ill., maps 29 cm

M.Sc. / The study looks into the sediment-bound metals (Fe, Mn, Cu, Cr, Cd, Co, Pb, Ni, Zn and Hg) of the Leeu/Taaibospruit catchment, which is impacted by agricultural, industrial and urban development. A number of chemical procedures, including total metal determination, the Tessier-sequential extraction scheme, the BCR Protocol, evaluation of the % TOC and determination of AVS to SEM ratios were applied to sediment samples collected from eight sites along the two rivers in the study area. Samples were collected during both high flow (summer) and low flow (winter) conditions. Following the chemical characterisation, bioaccumulation testing was conducted by exposing chironomid larvae to the sediment samples collected in from the study sites and determining their metal uptake relative to control specimens in uncontaminated sediments. These bioaccumulation results were then considered in conjunction with the chemical parameters in an attempt to identify any trends and correlations. Significant spatial and temporal differences were found in the metal concentrations from the study area. The total extraction results indicated that abundant amounts of Cr and Fe are present throughout the system. This was expected based on the make-up of the underlying geology. In addition, one of the sites, which is in close proximity to the town of Sasolburg, was identified as a potentially contaminated site. This site had significantly higher concentrations of Zn, Cu, Pb and, most notably, Hg when compared to the other sites. The elevated metal concentrations are most evident in samples collected under low flow conditions, but are also seen in the high flow Hg concentrations. Sequential extractions showed that Fe and Cr are concentrated in the residual phases of the sediment. Copper is largely present in the oxidisable fraction under low flow conditions, but also has considerable residual and reducible chemical forms. Manganese and Zn are distributed among all the different chemical phases and are therefore likely to be readily available for uptake by benthic organisms. The TOC was found to be highest during low flow conditions and at those sites with observable amounts of organic debris from the surrounding reeds and other vegetation. The AVS/SEM ratios were used to predict that due to the formation of insoluble metal sulphides, Cd, Cu, Hg, Ni, Pb and Zn are unlikely to be bioavailable at certain sites, i.e. the contaminated site 1 and at site 5, which only has agricultural impacts. In general, the bioaccumulation of Fe, Co, Ni, Cr and Mn was higher in the test larvae than the control larvae. Bioaccumulation of Cu, Pb, Zn and Hg levels were only higher than the control worms at sites where contamination was suspected to have taken place. Average bioaccumulation factors indicated that Hg is the metal that is most readily available for bioaccumulation, followed by Cu, Zn and Mn. All of these metals were bioconcentrated in the tissues of the test chironomids, while levels of Fe, Ni, Cr and Pb were found to be lower in the organisms than in the sediments. Although many of the chemical fractions were found to correlate significantly with the uptake of the different metals, the best overall correlation existed between the bioaccumulated metal and the total non-residual fraction. In fact, the sum of the first four steps of the Tessier-scheme correlated significantly with the bioaccumulated metal for all elements considered in the calculation, except for Pb. Additionally, the predictions made by the AVS model were found to be useful in justifying the behaviour and accumulation patterns of Hg, Zn and Cu at certain sites. The correlations and bioavailability clearly differed spatially, temporally and among the different elements. It is therefore suggested that prediction of the bioavailability and subsequent uptake of sediment-bound metals will require as many chemical and environmental factors as possible, and should include bioaccumulation and toxicity testing in order to examine the validity and completeness of these predictions.