If you have been reading through your annual water quality report, you may have come across a contaminant listed called thallium. This is a metal that can be found in public or private supplies of drinking water and it could pose a health risk in large quantities. So, here is a brief guide to thallium, so you ensure that you stay safe.A Brief Guide to Thallium

The Thallium Basics:

Thallium is found in ores that contain other elements. It is often used in the production of specialized electronic equipment, which can allow traces to be released into the environment as a consequence of this manufacturing. The EPA has determined that there are potential health risks associated with exposure to high levels of thallium, so through the Safe Drinking Water Act monitors and regulates supplies for thallium levels. The EPA Maximum Contaminant Level Goal for thallium is set at 0.5 parts per billion, which would eliminate any risk of health problems and based on this goal, the Maximum Contaminant Level is set at 2 parts per billion. This is the lowest possible level water utilities, and systems can reasonably be required to reduce this contaminant should it be found in drinking water supplies. This limit is part of the National Primary Drinking Water Regulations, and the EPA is charged with ensuring all public water supplies abide by these regulations.

The Potential Health Effects:

The reason why the EPA has set such a low MCL is that thallium has been linked to some serious health effects. Short term exposure at levels exceeding the MCL can cause gastrointestinal irritation and nerve damage. Prolonged exposure over a lifetime could lead to changes in blood chemistry, hair loss and damage to the kidneys, intestines, and liver.

How Thallium Can Enter Water Supplies:

Although thallium is not produced here in the United States, reports show approximately 4,500 pounds of thallium and related compounds were imported in 1987. There are also manmade sources of thallium pollution that include the gas emissions produced from cement factories, metal sewers, and coal burning power plants. The major source of elevated thallium levels in water is that thallium can also leach from ore processing. Unfortunately, thallium can accumulate in aquatic life and can bind to alkaline soils before migrating to the groundwater.

Is Your Water Affected by Thallium Contamination?

The thallium regulations came into effect in 1994 and from this date utility companies were required to regularly collect water samples and test for the presence of thallium at levels greater than 2 ppb. If the contaminant levels are found to be above the MCL consistently, water suppliers must take active measures to reduce the presence of thallium. In this scenario, your supplier must also notify the public using TV, radio, newspapers and other means. They may also need to take additional measures to prevent a serious public health risk such as providing an alternative drinking water supply. It would also be included in the annual water quality report provided by your utility company, along with the measures the utility company has taken to address the problem.

By Mark Williams (NicMar President Mark Williams holds degrees in Applied Science and Industrial Thermodynamics, along with Agricultural Mechanization and Systems Engineering from Ohio State University. He also holds the highest possible industry ranking, being WQA (Water Quality Association) LEVEL 6 Certified.)