Mapping the Risk: How Environment Shapes Parkinson’s Disease Risk – the Great Plains

Stretching from the Dakotas down through Nebraska, Kansas, and Oklahoma (with swaths of Texas, Wyoming, Colorado, and New Mexico), the Great Plains is America’s agricultural heartland. That strength comes with environmental trade-offs: heavy pesticide use, vulnerable aquifers, shifting air-quality patterns, and emerging pollution dynamics, all of which may contribute to an elevated risk of Parkinson’s disease (PD) across parts of the region.

Recent analyses point to Great Plains counties where PD risk tracks closely with herbicide/insecticide applications and fine particulate air pollution, suggesting more than aging or genetics is at word.¹

In this installment, we unpack the exposures most relevant to the Great Plains, what they are, where they come from, and practical steps communities and families can take to reduce risk.

Why the Great Plains Is on the PD Risk Map

Two recent lines of evidence bring the Great Plains into focus:

Air‑pollution “hotspots”: A national geospatial study found that people living in regions with median levels of fine particulate matter (PM2.5) had a 56% higher PD risk versus low‑pollution regions, identifying central North Dakota and parts of Kansas and Texas among PD hotspots.²
Agricultural pesticide: Preliminary work presented at the American Academy of Neurology identified 14 pesticides associated with higher PD rates in the Rocky Mountain–Great Plains region, with simazine, atrazine, and lindane showing some of the strongest associations.³

Together, these findings reflect the region’s unique mix of intensive agriculture and airborne exposures that can carry neurotoxicants across long distances and into homes and water supplies. ⁴

Key Environmental Factors Driving Risk in the Great Plains

1) Pesticide Exposure (Field & Ambient)

The Great Plains’ large‑scale corn, wheat, sorghum, and rangeland systems rely on herbicides and insecticides applied across expansive acreage. County‑level use estimates published by USGS (based on USDA data) show persistent, high agricultural applications across Plains counties. ⁵ ⁶

Specific agents with PD relevance include:

Paraquat and Rotenone: A large NIH study found that people who regularly used these pesticides for work were about 2.5 times more likely to develop Parkinson’s Disease than those who didn’t. These chemicals are harmful because they damage the energy-producing parts of brain cells and cause stress that kills nerve cells.⁷

Organophosphates and Organochlorines: Studies show that some pesticides—like chlorpyrifos and older insecticides such as lindane—are linked to a higher risk of Parkinson’s disease. In the Great Plains, research found strong connections between certain chemicals, including simazine, atrazine, and lindane, and higher PD rates in specific counties.⁸ ⁹

Why it matters here: Large‑scale applications increase the chance of drift and dust‑bound residues, elevating ambient exposure even for non‑applicators, particularly during windy seasons typical of the Plains.

2) Groundwater Vulnerability (Nitrates & Solvents)

The High Plains (Ogallala) Aquifer is extensively used for irrigation and drinking water and is broadly vulnerable to nitrate contamination from agricultural sources. USGS modeling shows notable swaths of the aquifer with elevated probabilities of nitrate exceeding background levels, tied to irrigated/non‑irrigated cropland intensity, shallow water tables, and low clay content. ¹⁰ ¹¹ ¹²

While nitrate itself is not established as a direct PD driver, its presence signals hydrogeologic vulnerability to other contaminants. Importantly, solvents such as trichloroethylene (TCE) and perchloroethylene (PCE), historically used in degreasing and dry‑cleaning, are persistent groundwater pollutants and have been associated with substantially higher PD risk. Emerging clinical observations and reviews continue to raise concern about TCE’s role in PD through mitochondrial dysfunction and neuroinflammation. ¹³ ¹⁴ ¹⁵

Why it matters here: Many Plains communities rely on private wells or small systems. Studies in agricultural regions have linked well‑water consumption in pesticide‑dense zones with higher PD risk, including associations with water‑soluble herbicides.

3) Air Pollution: PM2.5 & Smoke Transport

Although the Plains are less industrial than coastal corridors, PD risk has been linked to PM2.5 in multiple analyses, with specific Great Plains hotspots identified. Newer population‑based work also links higher PM2.5 and NO₂ exposure to increased PD risk and to more akinetic‑rigid PD phenotypes and dyskinesia. ¹⁶ ¹⁷ ¹⁸

Complicating matters, wildfire smoke has increasingly affected air quality across the Midwest/Plains, especially during the record 2023 Canadian fires, reversing years of PM2.5 progress and driving regional spikes in exposure. Peer‑reviewed analyses quantify long‑range smoke contributions to US PM2.5 and acute/chronic health impacts, underscoring how even distant fires can alter local exposures in a single season. ¹⁹

Why it matters here: PM2.5 can carry pesticide residues, metals, and combustion byproducts, all known to induce neuroinflammation and oxidative stress, issues implicated in PD.

4) Livestock Operations (CAFOs): Air & Water Co‑Exposures

The Plains host numerous concentrated animal feeding operations (CAFOs). While direct PD links are not established, CAFOs can degrade air (ammonia, hydrogen sulfide, organic dust) and water (nutrients, pathogens), adding respiratory and systemic stressors that may compound overall environmental burden. Chronic low‑level hydrogen sulfide exposure has neurological implications, though evidence for PD‑specific outcomes differs from classic parkinsonism profiles observed with certain toxicants. ²⁰ ²¹

How These Exposures Could Trigger PD

Mitochondrial Dysfunction: Certain chemicals like paraquat and rotenone (and some industrial solvents) damage the “power plants” inside brain cells. This makes it harder for dopamine-producing neurons to create energy, which can lead to their death. ²²
Oxidative Stress & Inflammation: Tiny particles in polluted air, pesticides, and smoke can trigger the brain’s immune cells to overreact. This causes inflammation and stress that harm the neurons responsible for movement.²³
Persistent & Cumulative Exposures: In the Great Plains, people may face multiple risks over decades, including pesticides, polluted water, and smoke from fires. These exposures add up over time, working together to increase Parkinson’s risk rather than one single cause. ²⁴

What Communities and Families Can Do

At Home & On the Farm

Water: Use NSF‑certified filtration (activated carbon + reverse osmosis) for private wells; test annually for nitrates and solvent/pesticide panels if near historic dry‑cleaners or heavy agriculture.
Air: Monitor AQI/PM2.5; employ HEPA air purifiers; seal homes better during smoke events and avoid outdoor exertion on high‑pollution days.
Pesticide Practices: Choose lower‑risk products, apply during low wind, and adopt integrated pest management to reduce overall use; maintain buffers from residences and wells.
Food: In high‑use counties, rinse produce thoroughly and prioritize organic for crops with heavier herbicide applications when feasible.

Local & State Policy

Phase‑down high‑risk chemicals (e.g., paraquat) and encourage safer alternatives statewide/regionally.
Expand groundwater cleanup for TCE/PCE sites; enhance well‑testing support for rural communities.
Enhance air monitoring in rural counties, especially during agricultural seasons and wildfire smoke incursions.
Data transparency: Use USGS/USDA pesticide mapping tools to inform local planning and exposure reduction strategies.

A Prevention Mindset for the Plains

The Great Plains exemplifies how geography, industry, and land use can converge to shape neurological risk. From pesticide intensity and aquifer vulnerability to PM2.5 spikes and smoke transport, the region’s exposures are layered and evolving. The science increasingly indicates that reducing ambient pollution and toxic chemical use may help lower PD risk and influence disease expression.

Awareness is power, and prevention is possible. By testing water, improving indoor air, modernizing pest management, and advocating for cleanup and monitoring, Great Plains communities can take concrete steps toward a future where location doesn’t dictate neurological fate.