Newer groundwater linked to higher Parkinson's risk

Study finds drinking water from carbonate aquifers associated with 24% higher risk of Parkinson's disease

Published on Mar. 2, 2026

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A new study has found that people whose drinking water came from newer groundwater had a higher risk of developing Parkinson's disease compared to those whose water came from older groundwater. The study, which looked at over 12,000 Parkinson's patients and 1.2 million people without the disease, found that drinking water from carbonate aquifers was associated with a 24% higher risk of Parkinson's compared to other aquifer types. Newer groundwater, from the past 75 years, in carbonate systems was also associated with an 11% higher risk compared to groundwater older than 12,000 years.

Why it matters

The study suggests that the age and source of groundwater could be an environmental risk factor for Parkinson's disease. Older groundwater is typically less contaminated, while newer groundwater has been exposed to more modern pollutants. Understanding the link between groundwater and neurological health may help communities assess and reduce environmental risks.

The details

Researchers looked at groundwater age, aquifer type, and drinking water source as potential indicators of exposure to neurotoxic contaminants. They found that carbonate aquifers, which are more vulnerable to surface contamination, were associated with a higher Parkinson's risk compared to glacial aquifers that tend to naturally filter contaminants. The protective effect of older groundwater was only seen in carbonate aquifers, where newly recharged water is more vulnerable to contamination.

  • The study included data from 2026.

The players

Brittany Krzyzanowski

A PhD researcher at Atria Research Institute in New York City who conducted this research while at Barrow Neurological Institute in Phoenix, Arizona, and is a member of the American Academy of Neurology.

American Academy of Neurology

The leading voice in brain health, with over 44,000 members, that provides access to the latest news, science and research affecting neurology.

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What they’re saying

“One way to examine our exposure to modern pollution is through our drinking water. Newer groundwater, created by precipitation that has fallen within the past 70 to 75 years, has been exposed to more pollutants. Older groundwater typically contains fewer contaminants because it is generally deeper and better shielded from surface contaminants. Our study found that groundwater age and location is a potential environmental risk factor of Parkinson's disease.”

— Brittany Krzyzanowski, PhD researcher (American Academy of Neurology)

“We speculate that the apparent protective effect of older groundwater is seen mainly in carbonate aquifers because these systems can show a clearer contrast between newer and older water. In these aquifers, newly recharged groundwater is more vulnerable to surface contamination, while older groundwater can remain cleaner if it is separated from recent inputs by a confining layer.”

— Brittany Krzyzanowski, PhD researcher (American Academy of Neurology)

“In contrast, glacial aquifers tend to slow groundwater movement and naturally filter contaminants as water travels underground. As a result, differences in contamination between newer and older groundwater in these aquifers may be smaller and therefore harder to detect.”

— Brittany Krzyzanowski, PhD researcher (American Academy of Neurology)

What’s next

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The takeaway

This study highlights that the source and age of our drinking water could be an important environmental factor in neurological health. Understanding the link between groundwater and conditions like Parkinson's disease may help communities better assess and reduce potential risks from contaminated water supplies.