ABSTRACT
Actinides (ACs) is the term used for the elements from actinium to lawrencium. Sometimes they are also included in the group of rare earth elements. All ACs are radioactive and release energy upon decay. Thorium (Th) is a silvery-white metal and its luster tarnishes in air due to the oxidation. The degree of oxidation greatly influences its physical properties. Phytoavailability of Th from soils is variable and controlled by various factors; however, it is often accumulated in roots. Uranium (U) is a silvery-white metallic element, weekly radioactive, but very stable. Uranium can be taken into the body by food, drinking water, or breathing air. People who work with materials and products that contain U may be exposed to its elevated amounts. Plutonium (Pu) is a transuranic radioactive metal of a silvery-gray appearance, which in air tarnishes and becomes coating when oxidized. Humans may be exposed to Pu by breathing air, drinking water, and eating food containing Pu.
