Industrial Water Pollution Tied to Incurable Brain Disease

Living near industrial facilities that emit water pollutants is associated with a higher risk of developing progressive supranuclear palsy (PSP), a rare brain disorder that affects movement and balance.An analysis of UK Biobank data showed that proximity to facilities emitting heavy metals, pesticides, and other water pollutants was associated with up to 66% higher odds of developing PSP, depending on the type of pollutant.The association was stronger among those who had lived at the same address for more than 40 years, particularly near facilities releasing heavy metals and other organic and inorganic pollutants.“These results suggest that environmental water pollutants potentially play a role in the development of progressive supranuclear palsy,” study investigator Charlie Weige Zhao, MD, of the Department of Neurology at Mass General Brigham and Harvard Medical School in Boston, said in a statement. “Further studies are needed to confirm these findings, but this is a step forward in understanding what raises a person’s chance of getting PSP.”The study was published online on October 28 in Neurology.Environmental CluesPSP is a rare neurodegenerative tauopathy of unknown cause, with no treatments currently available to slow or stop its progression. However, what causes it is largely unknown. Earlier research has raised questions about potential environmental exposures.For example, a study in Northern France identified a cluster of PSP cases potentially linked to nickel, chromium, and cadmium contamination in nearby water and soil, whereas another study suggested a possible link between well water consumption. However, the role of water pollution in PSP remains poorly understood.In an earlier UK Biobank analysis, the investigators found no significant association between air pollution and PSP. They subsequently turned their attention to industrial facilities releasing pollutants into waterways and the risk for PSP.Together this body of research prompted the researchers to examine whether residential proximity and its potential link to PSP.The dataset included more than 500,000 UK Biobank participants followed from 2007 to November 2025. Among these individuals, the investigators identified 221 PSP cases. These were matched by age and sex to 2249 control individuals without a diagnosis of parkinsonism or dementia. The mean age in both groups was 63 years, and 41.2% were women.Investigators used participants’ baseline residential addresses and 2007 data from the European Pollutant Release and Transfer Register to assess proximity to facilities emitting six pollutant groups. These included heavy metals, chlorinated solvents, persistent organic pollutants, pesticides, other organic pollutants, and other inorganic pollutants.There were 305 reporting facilities, including wastewater treatment plants, intensive aquaculture operations, chemical plants, and thermal power stations.Living within approximately 3 miles of a facility was considered close proximity. Residential distance served as a proxy for potential exposure, although the investigators did not directly measure participants’ exposure to pollutants.Closer Proximity, Higher OddsAmong participants who developed PSP, 38% lived within approximately 3 miles of a facility emitting heavy metals compared with 31% of control participants. Similar differences were observed for facilities releasing pesticides (16% vs 11%), other organic pollutants (36% vs 28%), and other inorganic pollutants (38% vs 28%).After adjustment for potential confounders and multiple comparisons, living near facilities emitting facilities was associated with a 66% higher odds of PSP (odds ratio [OR], 1.66). The odds of PSP were also higher among those living facilities releasing other inorganic pollutants (OR, 1.60), other organic pollutants (OR, 1.52), and heavy metals (OR, 1.38).The specific pollutants examined included pesticides such as atrazine, simazine, and diuron; inorganic pollutants such as phosphorus, nitrogen, and fluoride; organic chemicals included benzene, ethylbenzene, and toluene; and heavy metals such as lead, mercury, and cadmium.No significant associations were observed for chlorinated solvents or persistent organic pollutants.Among participants who had lived at the same address for more than 40 years, proximity to facilities releasing heavy metals (OR, 2.21), other organic pollutants (OR, 2.45), and other inorganic pollutants (OR, 2.40) was associated with higher odds of PSP. These associations were not observed among those with shorter residential histories.The odds of PSP declined as the distance from polluting facilities increased from approximately 3 to 6 miles.A separate analysis showed lower odds of PSP with greater distance from facilities releasing pesticides (OR, 0.86), other organic pollutants (OR, 0.91), and other inorganic pollutants (OR, 0.90).Exploratory FindingsThe study findings add to growing evidence that environmental exposures may contribute to PSP, although the study’s observational design cannot establish causality.Several limitations warrant caution. Many facilities released multiple types of pollutants, making it difficult to determine which substances might be associated with PSP. In addition, living near such facilities does not necessarily reflect actual exposure. For example, a nearby facility may not be the source of a participant’s drinking water.Consequently, the findings for individual pollutants should be considered exploratory, the investigators noted.Still, the results point to specific environmental exposures that warrant further investigation.“While these observational findings cannot establish causality, they suggest that specific environmental exposures may be worth further mechanistic study,” the investigators noted.The researchers called for confirmation in independent cohorts, including studies incorporating neuropathologic assessments and biomarkers to better evaluate toxin exposures and their relationship to PSP.Disclosure information for study authors is available in the original study publication.