TABLE OF CONTENTS

Title Page    –         –         –         –         –         –         –         –         –         i

Certification –         –         –         –         –         –         –         –         –         ii

Dedication   –         –         –         –         –         –         –         –         –         iii

Acknowledgements         –         –         –         –         –         –         –         iv

Table of Contents  –         –         –         –         –         –         –         –         v-vi

CHAPTER ONE

1.0 Introduction     –         –         –         –         –         –         –         –         1-3

CHAPTER TWO

2.0Biological role of cadmium – –         –         –         –         –         4-5

2.1 Occurrence      –         –         –         –         –         –         –         –         5-6

2.2 Resorption into Human Body        –         –         –         –         –         6

2.2.1  Digestive system    –         –         –         –         –         –         –         6-8

2.2.2  Respiratory System          –         –         –         –         –         –         8

2.2.3  Dermal Resorption –         –         –         –         –         –         –         9

CHAPTER THREE

3.0 Cadmium Induced Toxicity – –         –         –         –         –         10-12

3.1 Kidney Damage –         –         –         –         –         –         –         12-13

3.2 Effects of Cadmium in Reproductive Biology –         –         –         14

3.3 Bone Damage and the Itai-itai Disease –         –         –         –         15-16

3.4 Carcinogenesis – –         –         –         –         –         –         –         17

3.5 Cardiovascular abnormality –         –         –         –         –         –         18

CHAPTER FOUR:  SUMMARY AND CONCLUSION

4.1 Summary-        –         –         –         –         –         –         –         –         19-20

4.2 Conclusion-     –         –         –         –         –         –         –         –         20-21

References

CHAPTER ONE

1.0 INTRODUCTION

Cadmium (Cd) is a silvery-white, soft, ductile chemical metal with atomic number 48 and belonging to the group 12 element in d block and period 5. It was discovered by German chemist F. Strohmeyer in 1817 as a constituent of smithsonite (ZnCO3) from zinc ore. Electronic configuration of the cadmium is [Kr] 4d10 5s2. Cadmium concentration in the earth crust is 0.15ppm and the most common cadmium mineral is greenockite (CdS) (Page and Bingham, 2010).

Cadmium is recovered as a by-product from sulfide deposits, mainly those containing lead, zinc, and copper. Cadmium level in human increases with the age, it reach to an average of about 30mg in the age range 40-50 and after that decreases slightly (Fleischer et al., 2003).  Cadmium is hazardous to both environment and human beings. Cadmium present in atmosphere, water, or food when exposed to human in low concentration cause serious health problems and probably the death (Page and Bingham, 2010). Sources of cadmium human exposures are fossil fuels, iron and steel production, cement nonferrous metals production, waste incineration, smoking, fertilizers, etc. Activities like volcanic eruption, mining and use of phosphate fertilizers provides cadmium exposures indirectly as toxin from earth crust. Plants take up cadmium from the soil and form the major source of cadmium intake in non-smoking, non-occupationally exposed populations. There is a significant use of this heavy toxic metal in batteries, pigments, coating, plating, PVC stabilizers and alloys in industries (EFSA, 2009).

Renal disease and emphysema are observed in the workers working in battery plant due to the inhalation of the cadmium oxide dust over a long period of time. Due to excessive intake of cadmium in water and rice and low intake of calcium and vitamin D, there is effect in pregnancy and lactation. Cadmium in small amount absorbed in the kidney cause proteinuria when kidney concentration reaches a certain value. Interaction between Cd, Cu and Zn results in cadmium toxicology (Fassett, 2002). Cadmium is also absorbed and distributed in the other organ and tissues such as liver, spleen, pancreas, heart and testis. In human, the biological half-life of cadmium is 10-30 years (Goering et al., 2011). As cadmium is very harmful, its sources of emission and its direct and indirect interaction with soil, plants, water and animal are to be understood properly (Page and Bingham, 2010). Total usage of cadmium is small due to its toxic properties of the soluble salts. In 1968, metal production increases from about 100,000 lb per year to 31,000,000 lb per year due to its metallurgical properties such as corrosion resistance (Fassett, 2002). Regulatory limits have been decided at various levels according to EPA 5 parts per billion (ppb) or 0.005 parts per Million (ppm) of cadmium in drinking water, Food and Drug Administration (FDA) concentration In bottled drinking water should not exceed 0.005 ppm (5 ppb) and OSHA has an average permissive concentration of 5 micrograms per cubic meter in workplace air according to 8-hours workday, 40-hours work week (Martin et al., 2009).