2025 Public Health Laboratory Newsroom
Metals Laboratory Tests for Arsenic, Lead, and More
Within a Minnesota Department of Health building, there are a few laboratory rooms that have plastic faucets to minimize the amount of metal in the water and air. All air entering these rooms is filtered to remove as many particles of metals as possible. Anyone entering must put on booties and a lab coat. Cardboard is avoided because it contains a surprising number of metal particles.
In these rooms of the Metals Laboratory, metal particles could interfere with tests to detect metals like arsenic and uranium at rates of around one part per billion, or, in some cases, 1 part per 100 billion. The Metals Laboratory is within the Minnesota Environmental Laboratory, which is itself a section of the Minnesota Public Health Laboratory. The Metals Lab has specialized equipment and staff trained to analyze water, human blood and urine, and other substances for metals that pose danger to human health.
Testing for Metals in Water
A large part of the Metals Lab’s work is testing samples of drinking water and non-potable surface water sent by municipal water systems and other government agencies. The lab routinely tests these samples for 23 metals, including arsenic, barium, beryllium, thallium, cadmium, selenium, and mercury. All of these metals occur naturally in the soil and are dangerous to the human body at high concentrations. If the Metals Lab detects a significant level of any of these metals in a sample, the water system is informed and is responsible for resolving the problem at its source.
A 2025 study found that from 2013 through 2024, 107 contaminants were found in Minnesota water, including metals and other chemicals like PFAS. Arsenic was one of the most common contaminants.
There is no regulatory requirement for routinely testing water drawn from wells. About 40% of Minnesotan wells contain water with very small amounts of arsenic that have leached in from the surrounding soil. Drinking water from these wells for many years can be hazardous, especially for young children. If you regularly drink water from a well, please see Arsenic in Well Water for more information.
Lead is not prevalent in soil but is found in older household plumbing. When water travels through these pipes, lead can accumulate to dangerous levels. If you are concerned about lead in the water at your home or another location, visit Lead in Drinking Water.
A recently enacted Minnesota law mandates that all schools and child care centers send samples from all of their taps to the Minnesota Environmental Laboratory for lead testing. For larger schools, this can mean preparing more than 100 samples. Read more at How Minnesota Tests for Lead in Water at Schools, Child Care Centers.
On rare occasions, the Metals Lab tests water samples for uranium. A separate radiological chemistry team of the Minnesota Environmental Laboratory monitors the water near Minnesota’s two nuclear power plants, in Monticello and Prairie Island. If this team discovers a higher-than-usual level of radioactivity in a sample, it will send the sample to the Metals Lab to test for uranium.
Testing for Metals in Biological Samples
Several other programs use the Metals Lab to discover if people have high levels of certain metals in their bodies. One tests urine samples from pregnant women for mercury. Those who had elevated levels of mercury were contacted. Many had used certain skin-lightening products that contain mercury, which is especially dangerous to a growing fetus. By spreading the word about the dangers of these products, the program has already seen a reduction in the mercury levels of samples. Watch a talk about this program called Toxic Beauty.
Another program, called Healthy Kids Minnesota, regularly tests urine samples from children whose parents have volunteered them for the study. Read more about the Minnesota Environmental Laboratory’s role in the Healthy Kids program at Testing Minnesota Children for Harmful Chemicals.
One finding from Healthy Kids Minnesota is that people who eat rice once or more a day can accumulate high levels of arsenic in their bodies. Washing the rice before cooking it makes it safer to eat. (Learn more at What You Can Do to Limit Exposure to Arsenic on the FDA website.) Minnesota Department of Health epidemiologists are busy discussing this with affected communities, while the Department of Agriculture is investigating which brands of rice contain the most arsenic.
Healthy Kids Minnesota is also looking into exposure to manganese. Manganese has long been thought to be of a secondary concern, but evidence is growing that children exposed to too much manganese could develop learning and behavior problems. Read more at Manganese in Drinking Water.
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