Nowadays heavy metals such as thallium have received considerable
attention owing to their effects in the pollution of the
environment. Many thallium(I) compounds are highly soluble
in water and are readily absorbed through the skin. It has been
identified to be an environmentally important element due to its
toxic effects and because it is commonly found with lead, zinc,
iron, tellurium and the alkalis. Tl is known to have side effects
such as mutagenic, carcinogenic and teratogenic. Thallium(I) is
highly toxic to the biosphere even more than Hg, Cd, Pb and
Cu as well (Leonard and Gerber, 1997; Nriagu, 1998).