Fact Sheet: Thallium

Brief Overview:
Category: Metals
Acceptable Level: 0.002 mg/L MCL, Primary Drinking Water Standards
Follow up:
Natural occurring, Industry
Short and Long-term Health Effects
Test for Thallium and other metals
Activated Alumina; Ion Exchange
Source: Thallium is a metal found in natural deposits as ores containing other elements. The greatest use
of thallium is in specialized electronic research equipment.
Thallium is not produced in the US. Approximately 4,500 lbs. of thallium and its compounds were reportedly
imported in 1987. Man-made sources of thallium pollution are gaseous emission of cement factories, coal
burning power plants, and metal sewers. The leaching of thallium from ore processing operations is the major
source of elevated thallium concentrations in water. Thallium is a trace metal associated with copper, gold,
zinc, and cadmium.
Thallium does not long persist if released to water, but does have a strong tendency to accumulate in aquatic
life. If released to land, it may bind to alkaline soils, but may otherwise migrate to ground water.
Effect: Short-term: EPA has found thallium to potentially cause the following health effects
when people are exposed to it at levels above the MCL for relatively short periods of time:
gastrointestinal irritation; nerve damage.
Long-term: Thallium has the potential to cause the following effects from a lifetime exposure at
levels above the MCL: changes in blood chemistry; damage to liver, kidney, intestinal and
testicular tissues; hair loss.
Follow up: Treat and re-test for metals.
Treatment: Activated Alumina; Ion Exchange
Following installation of this system, the consumer should have the treated water tested for thallium to verify
thallium reduction is being achieved and the system is functioning properly.
For more information visit the USEPA web site: