Thallium

Consumption and Health

The greatest use of this metal is in specialized electronic research equipment (electronic devices, switches, and closures, primarily for the semiconductor industry). It also has limited use in the manufacture of special glass and for certain medical procedures.

Thallium is toxic and does not have any positive effect on people's health if consumed through food and water or absorbed in larger quantity from the atmosphere. Recent research in China, for instance, shows that thallium concentration in plants exhibits species-dependent preferences, decreased from green cabbage toward corn. The highest level of Tl [Page 910]in green cabbage is up to 500 milligrams (mg)/kilogram (kg) as dry weight, surpassing the values of Tl in the soils in which the green cabbages grow.

The Maximum Contaminant Level Goals (MCLG) for thallium in water set by the Environmental Protection Agency (EPA) is 0.5 parts per billion (ppb), while the enforceable standard called a Maximum Contaminant Level (MCL) is set at 2 ppb. Short-term health effects of the thallium consumed above MCL may include gastrointestinal irritation and nerve damage, and long-term changes in blood chemistry, damage to liver, kidney, intestinal and testicular tissues, polyneuropathy, visual impairment, hair loss, and even death.

The Occupational Safety and Health Administration (OSHA) has set an exposure limit of 0.1 mg per cubic meter (0.1 mg/M3) for thallium in workplace air. The National Institute for Occupational Safety and Health (NIOSH) has recommended that 15 mg/M3 of thallium be considered immediately dangerous to life and health. This is the exposure level of a chemical that is likely to cause permanent health problems or death.

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