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Title:	Metal Distribution In Sabah And Sarawak Marine Sediments: Study Of Sequential Extraction Procedures, Multi-Elements Detection Techniques And Current Status
Authors:	Amel Yousif Ahmed Ibrahim (P46396)
Supervisor:	Md. Pauzi Abdullah, Prof. Dr.
Keywords:	Metal Distribution In Sabah And Sarawak Metal Distribution In Sabah Metal Distribution In Sarawak Sabah And Sarawak Marine Sediments Metals-Environmental aspects-Sabah
Issue Date:	7-Nov-2013
Description:	Evaluation of metal content in sediments is important because sediment can act either as a sink or as a source of metals. The amount of a given metal that can be released from sediment depends on the metal species, so the total metal concentration is a poor indicator of metal bioavailability, mobility and toxicity. The aims of this study are to evaluate the effectiveness of different sequential extraction protocols namely those based on Tessier (with some modifications) and the extraction procedure of the Commission of the European Communities Bureau of Reference (BCR). The different methods of multielemental detection techniques namely Neutron Activation Analysis (INAA), Inductively Couple Plasma/ Mass Spectrometry (ICP/MS) and X-ray Fluorescence (XRF) were used as final detection techniques. The selected techniques were applied to study the distribution, sources and status of heavy metal in the marine sediments of Sabah and Sarawak, Malaysia. The sediment samples were collected from the coast of Sabah and Sarawak. Twenty six sampling sites were selected at which 78 samples were collected at different depths (between 3.5-109 m). Twelve surface sediment samples (depth of 1meter), designated as control samples, and were collected at the coasts of Taman Negara Bako and Taman Negara Pulau Talang in Sarawak. The samples were digested for total metal content using microwave acid digestion procedure for ICP/MS analysis. Direct measurements for total metal content were carried out using XRF and INAA. For the determination of the chemical forms of the elements, Tessier scheme with some modifications and the BCR scheme were applied. Quality control was performed using different standard reference materials. The results of total metal content show significant differences between samples and control except for As and Ba. This result gives an indication that all elements under study may have anthropogenic sources except As and Ba. However, the results of total metal concentrations in the three layers show no significant different, indicating no significant variations in the input of metal pollution in the coastal environment over the years. The enrichment calculation shows that all elements show enrichment except Co, Fe and Mn which show no enrichment. Ba, Cr, Cu Ni and V show minor enrichment , Pb and Zn are moderately severe , while As and Cd are severe. However, Se is considered extremely severe to the environment. The results of principal component analysis(PCA) show four components, component 1 show loading for Co, Cr Fe, Ni and V. Component 2 Ba and Cd, while As and Se are loading in component 3. Component 4 only Al (which is a reference element) is loading there. The comparison between ICP/MS, XRF and INAA show that the three techniques agree with each other in certain elements and disagree on others. However, on the whole they complement each other to cover the concentration ranges of all elements under study. The results of modified Tessier and BCR sequential extraction procedures show that the two procedures agree with each other in the distribution of As, Cu, Fe and V and disagree in the distribution of the other elements through the chemical fractions. This may be due to the different extraction conditions applied in the two procedures, because elements which are difficult to extract, are more affected by the extraction conditions applied in the particular. The longer steps and the requirement of more experimental works in Tessier scheme give the BCR an advantage over the Tessier. However, the longer steps of Tessier can effectively give more information about the distribution of a particular element through the chemical fractions. According to the risk assessment code (RAC) calculations, the sediments of Sabah- Sarawak are at medium risk.,PhD
Pages:	169
Call Number:	TD879.M47 .I248 2013
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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