TABLE OF CONTENTS While this chapter may appear out of context in a book concerning radioactive waste we feel it is appropriate to compare problems arising from heavy metal elements to those associated with radionuclides. Unlike radioactive elements, the toxicity of stable elements does not diminish with time; they can only change form. Certain forms of some metals can be quite toxic even in relatively small amounts. Unless precautions are taken, metal contamination is likely to be with us indefinitely.
Several examples of lack of care when dealing with heavy metals, such as Pb, Cd and Hg, demonstrate the seriousness of high levels of exposure. In the 1950s, chronic Cd poisoning from rice, coupled with dietary deficiencies, caused an epidemic of kidney damage and a painful skeletal disease in Japan. A disease caused by Hg poisoning from eating fish from a polluted bay in the same country became known as Minamata disease. Severe effects on birdlife were observed in the 1950s and 1960s when many farmers laced their seeds with methyl Hg to prevent mould growth. Arsenic poisoning of water resources, while often not man-made, is currently a serious problem in many areas particularly in low-lying Bangladesh.
Metals occur in many forms, e.g. as ions dissolved in water, as vapours, or as salts or minerals in rock, sand and soil. They can also be bound to organic or inorganic molecules, or attached to particles in the air. Both natural and anthropogenic processes and sources emit metals into...
