Overview
- After adjustments for demographics and air pollution, drinking water from carbonate aquifers was linked to a 24% higher Parkinson’s risk versus other aquifer types and 62% higher risk versus glacial aquifers.
- Newer groundwater in carbonate systems—recharged within the past ~70–75 years—was associated with an 11% higher risk compared with ice‑age groundwater older than 12,000 years.
- The analysis matched 12,370 people with Parkinson’s to more than 1.2 million controls living within three miles of 1,279 sampling sites across 21 major U.S. aquifers.
- Researchers emphasize the study is observational and cannot establish causation, noting a key limitation that nearby residents were assumed to share the sampled aquifer’s characteristics and groundwater age.
- Carbonate aquifers are widespread in parts of the Midwest, South and Florida, whereas glacial aquifers are concentrated in the Upper Midwest and Northeast, highlighting where follow‑up exposure assessments may be most relevant.