EDXRF ANALYSIS OF THE LEVEL OF HEAVY METALS IN MARINE FISHES FROM RAKHINE COASTAL REGIONS PhD DISSERTATION WIN WIN MAW DEPARTMENT OF PHYSICS UNIVERSITY OF YANGON MYANMAR SEPTEMBER 2004 2 CONTENTS Page ACKNOWLEDGEMENT ABSTRACT CHAPTER I INTRODUCTION 1 1.1 General Features of Fishes 1 1.2 Types of Fish 2 1.2.1 Bony Fish and Cartilaginous Fish 3 1.3 Fish Shapes 4 1.4 Shellfish 4 1.5 Seafood 6 1.6 Seafood Quality and How to Check It 8 1.6.1 Smoked Seafood 9 1.6.2 Frozen Seafood 9 1.7 Shellfish and Packaging 10 1.7.1 Live Shellfish 10 1.7.2 Cooked Shellfish 11 1.8 Seafood Production, Consumption and Trade 13 1.9 Reducing Hazards with HACCP 17 1.9.1 Additional Protections 19 1.10 XRF - The Universal Metrology Method 20 CHAPTER II BACKGROUND THEORY OF X-RAYS 23 SPECTROSCOPY 2.1 Introduction of X-Ray 23 2.2 Nature of X-Rays 23 2.3 X-Ray Production 25 2.4 Properties of X-Rays 26 2.4.1 Fluorescence 27 2.4.2 Ionization 27 3 Page 2.4.3 X-Ray Diffraction 27 2.5 Interaction with Matter 28 2.5.1 Photoelectric Effect 28 2.5.2 Compton Effect 28 2.5.3 Pair Production 28 2.6 Application of X-Rays 29 2.6.1 Research Application 29 2.6.2 Industry Application 30 2.6.3 Medicine Application 31 CHAPTER III ANALYSIS OF X-RAY SPECTRA 33 3.1 Introduction 33 3.2 Spectrum Analysis 33 3.2.1 Continuous Spectrum 34 3.2.2 Absorption Spectra 36 3.3 Naming Transitions 37 3.4 Moseley's Law 38 3.5 Line Intensities 41 3.6 Satellite Peaks 42 3.7 Wavelength Shifts 43 3.8 Spectroscopic Analysis 46 3.9 WDS vs. EDS Detection 47 3.10 Calibration Curves 50 3.11 Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometry 51 3.11.1 Performance and Advantages 52 3.11.2 Faster Analysis Time 52 3.11.3 Lower Cost of Analysis 53 3.11.4 Interferences of Elements 53 4 Page 3.11.5 Volatile Metals by EDXRF 54 3.11.6 EDXRF Hardware 54 3.12 Fundamental Parameters Analysis 56 3.12.1 General Bulk and Thin-Film Analysis 56 3.12.2 Analysis with or without Standards 57 3.12.3 Spectrum Calibration 57 3.12.4 Background Removal 58 3.12.5 Escape Peak and Sum Peak Removal 58 3.12.6 Smoothing 58 3.12.7 Intensity Extraction 58 3.13 Heavy metals 59 3.13.1 The Illnesses due to Heavy Metals 59 3.13.2 Absorbing Heavy Metals 61 CHAPTER IV EXPERIMENTAL PROCEDURE AND RESULTS 62 4.1 Samples Collection and Preparation 62 4.2 Energy Dispersive X-Rays Fluorescence 62 Spectrometer for Shimadzu EDX-700 4.3 Experimental Results 66 CHAPTER V DISCUSSION AND CONCLUSION 75 5.1 Discussion 75 5.2 Conclusion 95 REFERANCES 5 ABSTRACT Thirty-three marine fish samples were collected from Southern portion of Rakhine coastal strip of Myanmar. Twenty-one marine fish samples were collected from Thandwe Region and twelve marine fish samples were collected from Kyauk Gyi Region. The concentrations of heavy metals contained in these marine fish samples were analysed by using Energy Dispersive X-Ray Fluorescence (EDXRF) method and from these concentration results, the differences and varying of heavy metals concentrations between the two regions were analysed and discussed. The average concentrations of elements contained in each type of marine fish samples and the average concentrations of elements contained in the marine fish samples of each location are calculated. According to this research work, marine fish samples collected from Kyauk Gyi Region have higher concentrations of heavy elements than that of the Thandwe Region. Therefore, sea water of Kyauk Gyi Region has more heavy elements pollution than the sea water of Thandwe Region. 6 CHAPTER I INTRODUCTION 1.1 General Features of Fishes Fish diverse group of animals live and breathe in water. Fish are cold-blooded vertebrates, like reptiles, and have skeletons like mammals and reptiles. Some fish have skeletons made of bone. These include cod, plaice, and mackerel. Other fish have skeletons made from cartilage. These include sharks and rays. Their skeletons are softer and more bendy than animals with bone skeletons. The skin of most fish is protected by scales, which cover the surface of the skin. They also have gills, which enable them to live and breathe under water. Most fish have fins for swimming, scales for protection, and a streamlined body for moving easily through the water. Fishes live in nearly every underwater habitat, from near-freezing Arctic waters to hot desert springs; from mud in dried-up tropical ponds to the deepest ocean abyss. Special antifreeze chemicals in the blood of Antarctic ice fish enable them to survive in water below 0° C (32° F). Desert pupfish found in hot springs of western North America live in temperatures higher than 40° C (100° F). Killifish release their eggs, or spawn, as the dry season begins in the tropics of South America and Africa, leaving their eggs to dry in the ground until the rains return six months later. In the deep ocean, where sunlight never reaches, many fishes cooperate with glowing bacteria to create their own light for communication and to attract mates and prey. With approximately 25,000 recognized species, fishes make up the most diverse vertebrate group, comprising about half of all known vertebrate species. New fishes continue to be discovered and named at the rate of 200 to 300 species per year. With this vast number of different fishes comes a diversity of sizes and shapes, from huge whale sharks that reach 12 m (40 ft) in length to the smallest vertebrate, a tiny goby, measuring only 1 cm (0.4 in) long. 7 Fishes are generally streamlined with a pointed snout and pointed posterior and a broad propulsive tail. Unlike the shape of a human body, a fish‘s body shape is ideal for speeding through the water without creating excess resistance. This torpedo-shaped body is typical of the fastest-swimming fishes, the billfish and the tunas. One billfish, the sailfish, can swim in bursts of over 110 km/h (70 mph). Tunas are built for long-distance endurance as well as speed, swimming as fast as 50 km/h (30 mph) and migrating as far as 12,500 km (7700 mi) in only four months. Other fishes come in a wide variety of shapes. The snakelike eels, flat halibuts, and boxy puffers are all slower swimmers that have evolved distinctive bodies best adapted to their specific habitats. Unlike fishes that swim through the open water, these fishes have adapted to life in caves, on the ocean floor, and among coral reefs where speed is less important than camouflage or maneuverability Some shellfish, like lobsters, crabs and prawns, have exoskeletons. That means their skeleton is on the outside of their bodies. These animals with exoskeletons are called crustaceans. Some shellfish are molluscs. They are protected from danger by withdrawing into a hard shell, which grows in size as the shellfish grows. Other molluscs have soft bodies with a shell inside, like squid and octopus. There are more than 21,000 different kinds of seafood. Nearly half of these live in the sea and the rest in rivers and lakes. The species commonly eaten as seafood live at different depths, from near the surface to some of the deepest parts of the ocean. (12) 1.2 Types of Fish Fish are classified into two types: Demersal and Pelagic. Demersal species live on or near the seabed and are normally called white fish. This means that the oil in the fish is concentrated in its liver. They may have round bodies (cod), or flat bodies (plaice). The flat-bodied fish live on the seabed whilst round-bodied fish live close to the seabed. 8 Pelagic fish swim in large shoals and are found close to the surface. These are fish such as herring or mackerel which have oil stored in their flesh and are known as oil-rich fish. Tuna is a pelagic species that is found in warmer waters of the world. Prawns are found in the seas and oceans of the world as well as the estuaries of rivers. In cold waters, they are caught in the sea by fishing boats with nets that are put out at either side of the boat. In tropical countries, prawns are harvested from prawn farms, which may cover many hectares of coastal land or land in the very big river deltas such as the Ganges and Brahmaputra in Bangladesh. Seafood feed on various foodstuffs which range from the smallest to the largest organisms. The type of food eaten in terms of nutrition is represented by what is called the food chain. This starts with the smallest organisms, single celled plants and animals which are collectively called phytoplankton or plankton. Plankton are tiny, and float in the sea in clouds. The food chain progresses to grass and weed feeders, through zooplankton feeders and bottom feeders, to the carnivorous fish which eat smaller fish. Phytoplankton feeders tend to have large mouths but no teeth, bottom feeders have their mouths on the underside of the head whereas grass feeders and carnivorous fish have mouths at the front of the head. There are exceptions to these generalisations. Sharks, which are carnivorous, have their mouths on the lower side of their head. (12) 1.2.1 Bony Fish and Cartilaginous Fish Bony fish are covered with scales, which are flat plates.