Golf Courses, Pesticides, and Parkinson’s Disease: The Chemicals Behind the Green

A golf course can look like one of the healthiest places to spend a day, with fresh air, open space, walking, and acres of green grass. But keeping that landscape pristine often means using herbicides, fungicides, insecticides, and other treatments. A 2025 study has linked living near golf courses with higher odds of Parkinson’s disease, with pesticide exposure as one possible explanation [1]. These chemicals can affect the nervous system, hormones, and other parts of the body, and may move through air, soil, and water [2][3]. Before you drive your golf cart off the green, we’ll break down the risks and ways to reduce exposure without ditching your tee time.

Living Near Golf Courses and Parkinson’s Risk

When it comes to environmental health on the golf course, the biggest hazards are not always the ones hiding in the sand trap. In a 2025 study, researchers compared 419 people newly diagnosed with Parkinson’s disease with 5,113 people without the disease across 27 counties in Minnesota and Wisconsin [1].

These experts examined where participants lived relative to 139 golf courses, their municipal water sources, and how easily local groundwater could become contaminated. The findings raised some eyebrows.

Compared with people living more than six miles from a golf course, those who lived closer generally had higher odds of Parkinson’s disease.

The increased risk of Parkinson’s disease among those near a golf course was:

More than twofold within one mile
Nearly threefold between one and two miles
Just over twofold between two and three miles

Overall, the pattern suggested that Parkinson’s odds tended to decrease as distance from a golf course increased. Researchers can’t simply chalk up these results to par for the course. They raise vital questions about what may be driving the association between Parkinson’s and people who live near golf courses.

The answers are tied to the air they breathe, water they drink, and other chemicals that touch their skin. Pesticide chemicals can travel for miles with the wind, both during and after spraying [4].

Why the Exposome Matters for People Near Golf Courses

Most of us do not encounter one chemical once and in isolation. We experience thousands of environmental influences over the course of our lives through the air we breathe, water we drink, food we eat, products we use, materials in our homes, chemicals at work, and the places where we live and spend our time.

Scientists use the term exposome to describe this larger picture. The exposome is the total of the environmental exposures we encounter throughout life, along with how our bodies respond to them [5].

The exposome gives us a more realistic way to think about diseases like Parkinson’s. Instead of asking whether one round of golf caused a disease decades later, researchers can ask how multiple exposures may accumulate, interact with genetics, change with age, and affect vulnerable biological systems over time.

That is also why the golf-course study is so eye-opening. It shifts attention away from the idea that exposure only comes from products we intentionally buy and use. Our local environment can matter too.

A chemical used on a lawn, agricultural field, golf course, industrial site, or other nearby property can potentially become part of someone else’s environment through air, dust, runoff, or water.

How Do Pesticides on Golf Courses Affect Local Water Safety?

The connection between golf courses and Parkinson’s disease becomes more concerning when water enters the picture. In the 2025 study, people whose public drinking water came from groundwater systems in areas with a golf course had nearly twice the odds of Parkinson’s disease compared with those served by systems in areas without one.

Groundwater can be easier to contaminate when it lies close to the surface or beneath loose, sandy soils. In those areas, water can carry pesticide residues more easily through the ground and into underground water supplies.

Researchers found that people living in areas with both a golf course and more vulnerable groundwater had 82% higher odds of Parkinson’s disease than those in golf-course areas with less-vulnerable groundwater.

Evidence also suggests that pesticides used on golf courses can make their way into groundwater. A Cape Cod study cited by the researchers found seven different pesticides in groundwater beneath four golf courses, including chlorpyrifos and 2,4-D [6]. Chlordane was detected in drinking water at more than 200 times its health guidance level!

So how does a chemical sprayed on grass end up somewhere else? Think about what happens after a heavy rain or a round of irrigation.

Some pesticide residues dissolve in water and move downward through the soil, a process called leaching. Others stick to soil particles that can wash away with runoff, carrying those chemicals into storm drains, streams, ponds, and other surface waters.

As we mentioned, sandy or highly permeable soils can make it easier for certain pesticides to travel downward toward groundwater and the aquifers that supply wells and drinking water. These same pathways help explain how pesticides can move through the broader environment.

Pesticide residues can settle on nearby plants, remain in the soil, or be carried away by rain and irrigation. From there, they can wash into streams and ponds, seep into groundwater, or be taken up by plants. This migration creates potential pathways into the water we drink and the food we eat.

Why Are Pesticides and Parkinson’s Disease Linked?

Pesticide exposure may seem limited to farms or people who spray chemicals for a living. However, people and businesses also use pesticides on lawns, parks, golf courses, and other managed landscapes. The widespread, routine use of pesticides is a primary reason researchers are studying how repeated exposure may affect the brain over time.

Parkinson’s disease is a progressive neurological disorder that affects movement and other functions of the nervous system. One of its defining features is the gradual loss of brain cells that produce dopamine. Dopamine is a neurotransmitter, or chemical messenger, that helps regulate movement, motivation, learning, and other important functions [7].

Scientists have spent decades trying to understand why these cells become damaged. Genetics plays a role, but it does not explain the whole picture. Environmental exposures (our exposome) have become an important part of the investigation.

The air we breathe and water we drink play a significant role in developing our exposome. That’s what makes the use of pesticides on golf courses so alarming, especially for those who live close to them.

The National Institute of Environmental Health Sciences reports that population studies have consistently linked pesticide exposure to Parkinson’s disease [8]. One large U.S. study of more than 140,000 people found that those who reported pesticide exposure had about a 70% higher incidence of Parkinson’s disease than those who did not [9].

Similar patterns have been seen in other groups, including agricultural workers, pesticide applicators, and people living in areas with heavier pesticide use [10]. Together, these findings are one reason researchers continue to examine how pesticide exposure may contribute to Parkinson’s risk.

That does not mean every pesticide poses the same concern. “Pesticide” is an umbrella term covering many different chemicals, each with its own uses, toxicity, and effects on the body. Understanding which chemicals are involved, how people encounter them, and how much exposure occurs is key to identifying where exposure can be reduced.

How Could Pesticides Affect the Brain?

Not all pesticides affect the body in the same way. However, researchers have identified several ways certain pesticides may interfere with brain health and potentially contribute to diseases like Parkinson’s.

One area of concern involves mitochondria, the tiny structures inside our cells that produce energy. Brain cells that make dopamine need a lot of energy to function, which may make them especially vulnerable when mitochondria are damaged. Some pesticides studied in Parkinson’s research can interfere with these cellular “power plants,” making it harder for brain cells to work properly [11].

Another concern is oxidative stress. Our cells naturally produce unstable molecules called free radicals, and the body normally keeps them under control. Some pesticides can cause too many of these molecules to build up or weaken the body’s defenses against them. Over time, that stress can damage proteins, DNA, cell membranes, and the mitochondria cells rely on for energy [12].

Researchers are also looking at inflammation in the brain, changes in how dopamine works, and problems with the cell’s cleanup system. When that cleanup system slows down, damaged proteins and other waste can build up. Over time, these problems may put extra stress on the dopamine-producing brain cells that are already vulnerable in Parkinson’s disease [13].

Most Common Chemicals Studied for Parkinson’s: Not Commonly Used on Golf Courses

Before we look closer at Parkinson’s development and pesticide exposures from golf courses, we must acknowledge an important finding. Some of the strongest pesticide research on Parkinson’s disease focuses on two chemicals you are unlikely to encounter on a golf course: paraquat and rotenone [12].

Researchers have studied paraquat and rotenone extensively because both can disrupt biological systems involved in Parkinson’s disease, including the dopamine-producing brain cells that are progressively lost in the disease [14]. NIEHS reports that people who occupationally used either paraquat or rotenone developed Parkinson’s disease about 2.5 times more often than nonusers [12].

Paraquat dichloride (paraquat): Paraquat is a powerful herbicide used primarily in agriculture and is restricted to trained, certified applicators. Exposure therefore tends to be most relevant to agricultural workers and pesticide applicators rather than golfers. EPA specifically prohibits paraquat use on golf courses, recreational parks, schools, playgrounds, and residential areas [15]. Researchers are especially interested in paraquat because it can increase oxidative stress, which can damage dopamine-producing brain cells [16].
Rotenone: Rotenone has also played a major role in Parkinson’s research because it interferes with mitochondria, the structures cells depend on for energy [17]. Today, its primary use in the United States is as a restricted-use piscicide. Therefore, rotenone is applied to lakes, ponds, reservoirs, and streams to control unwanted fish [18]. Pesticide applicators and people involved in fisheries or aquatic management are more likely to be exposed to rotenone than golfers walking on treated turf.

These chemicals help show how pesticide exposure can damage brain systems involved in Parkinson’s. Paraquat and rotenone are not used on golf-course turf, but the higher Parkinson’s odds seen near golf courses raise a bigger question: could other pesticides used on courses affect the brain in similar ways these chemicals have been shown to?

More research is needed to identify which chemicals and exposure levels may be behind that link. Hopefully more open discussions about content like this can help create a world with stricter regulations and safer pesticide control at golf courses.

What Kinds of Pesticides are Used on Golf Courses?

A deep breath on the back nine may come with more than fresh air. Golf course pesticides can travel through spray droplets, vapors, dust, soil, and water. Their pervasiveness creates several ways for golfers and workers to come into contact with them.

Golf courses use different pesticides for different jobs. Here are some of the chemicals most relevant to turf management and the human-health effects researchers are watching.

Herbicides: Keeping Weeds Off the Fairway While Being a Pest to Our Health?

Herbicides kill or suppress unwanted plants, and several have a long history of use on golf-course turf.

2,4-Dichlorophenoxyacetic acid (2,4-D): Widely used to control broadleaf weeds on turf, 2,4-D has also appeared in Parkinson’s research [19]. In one multicenter study, occupational use of 2,4-D was associated with about 2.6 times the odds of parkinsonism [20].
Mecoprop (MCPP): This common turf herbicide has also been used on golf courses and was specifically highlighted in the 2025 golf-course and Parkinson’s study. EPA toxicology assessments have identified the kidneys as a target organ following repeated exposure [21].

If you see an area that has recently been treated, follow posted re-entry instructions and avoid unnecessary contact with wet or freshly sprayed turf. You can also ask your course whether it uses Integrated Pest Management, which can help reduce routine pesticide use by targeting treatments only when and where they are needed.

Fungicides: Fighting Disease on the Green While Starting It In Our Bodies?

Closely cut, heavily watered turf is vulnerable to fungal disease, which is why fungicides can be a major part of golf-course maintenance.

Chlorothalonil: EPA specifically lists golf courses among its registered uses. The agency issued new mitigation measures in 2025 to reduce risks to people and the environment associated with this fungicide [22].
Thiophanate-methyl: Used on golf-course greens, tees, and fairways, this fungicide has been linked in animal toxicity studies to effects on the liver and thyroid. EPA has classified it as “likely to be carcinogenic to humans” based largely on liver tumors in mice and thyroid tumors in rats [23].
Manganese ethylene-bis-dithiocarbamate (Maneb): This fungicide is especially relevant to Parkinson’s research. NIEHS identifies maneb among pesticides studied in connection with Parkinson’s onset and progression, with research focusing on oxidative stress, mitochondrial dysfunction, and damage to dopamine-producing brain cells [23][24].

Since fungicides may be applied repeatedly during periods when turf disease pressure is high, timing can matter. Wash your hands before eating, drinking, or touching your face during a round, and consider keeping golf shoes and other turf-contact gear out of your main living space when you get home. Avoiding freshly treated areas and following course notices are still useful precautions.

Insecticides: Targeting Insects…and Potentially the Nervous System?

Several insecticides historically used on turf work by disrupting insects' nervous systems. Scientists believe that some insecticide chemicals can affect the human nervous system through similar biological pathways.

Chlorpyrifos: This organophosphate insecticide has a history of golf-course use and is strongly neurotoxic at sufficient exposure levels. EPA has identified concerns related to neurodevelopment, particularly during pregnancy and childhood, and NIEHS includes chlorpyrifos among pesticides investigated in Parkinson’s research [25].
Diazinon: Another organophosphate pesticide studied in relation to Parkinson’s, diazinon disrupts acetylcholinesterase, an enzyme essential for normal nerve signaling [26]. NIEHS includes it among pesticide exposures investigated in relation to Parkinson’s onset and progression.
1-Naphthyl methylcarbamate (Carbaryl): Carbaryl has been used on golf-course turf and works by inhibiting acetylcholinesterase, an enzyme needed for normal nerve signaling [27]. EPA reports that prolonged low-level exposure can cause neurological symptoms including headaches, memory loss, muscle weakness, and cramps [28].

With insecticides, reducing direct contact is especially worthwhile because many of these chemicals are designed to interfere with nerve signaling. When possible, check whether your course posts pesticide-application schedules and avoid playing during or immediately after treatment periods. Wearing socks, closed shoes, and clothing that limits prolonged skin contact with treated turf can add another simple layer of protection.

PFAS Pesticides: “Forever Chemicals” on the Fairway

PFAS are not just found in cookware, food packaging, and stain-resistant fabrics. Fluorinated chemicals are also used in some pesticides to help the formulas stay stable, spread effectively, and resist breaking down too quickly after application [29].

Some pesticides contain fluorinated chemicals that can fall into the PFAS category, depending on the state. For instance, Minnesota classifies more than 90 pesticide active ingredients as PFAS, even though the federal government may not label all of those same chemicals as PFAS [30].

Dithiopyr: This herbicide is used to prevent crabgrass and other weeds on golf-course fairways, tees, and roughs. Minnesota classifies dithiopyr as a PFAS because of its fluorinated chemical structure [31].
Florylpicoxamid: In May 2025, EPA under President Trump approved this new fungicide for food crops and golf-course tees, greens, and fairways [32]. Minnesota considers florylpicoxamid a PFAS, while EPA does not. EPA uses a narrower definition that excludes this chemical based on its structure. EPA found no human-health risks of concern when it is used according to the label, but identified potential risks to fish, aquatic animals, some insects, and plants.

Another potential source is the pesticide container itself. EPA testing found that PFAS can form during the fluorination of certain plastic pesticide containers and then leach into the product stored inside. The agency detected eight different PFAS, including PFOA, at levels of 20–50 parts per billion in container rinses [33].

Why does that matter? It means PFAS can end up in a pesticide even when the active ingredient itself is not considered PFAS. The packaging can become an additional source of contamination before the pesticide is ever sprayed!

Want to limit this added exposure? Ask your course what pesticides it uses and whether any contain PFAS-classified or fluorinated ingredients. Courses that use Integrated Pest Management, minimize unnecessary chemical treatments, and openly share what they spray make it easier for golfers to make informed choices.

Do Golf Courses Tell Golfers When the Course Was Sprayed?

Some golf courses will tell you what pesticides they used and when they sprayed last, but not always. There is no single nationwide rule requiring every golf course to publicly list exactly what was sprayed and when.

Requirements vary by state. Some states require courses to post notices showing the application date, treated areas, pesticide name, or re-entry precautions. In other places, golfers may only see a general pesticide-use notice or no public posting at all.

States with some of the strongest golf-specific protections include:

California
Colorado
Connecticut
Massachusetts
Michigan
Washington

Meanwhile, other states require less communication about pesticide application from golf courses, such as:

Florida
Georgia
Illinois
Wisconsin

These transparency differences make it worth asking the clubhouse yourself. Before you tee off, check the clubhouse or first tee for pesticide notices, or ask the superintendent or pro shop: “What was sprayed today, where was it applied, and is there a re-entry period?” Asking questions is a simple way to reduce unnecessary exposure, especially if parts of the course were recently treated.

Transparency can also tell you something about how a course manages pesticides overall. Courses that clearly communicate application timing, treated areas, and Integrated Pest Management practices make it easier for golfers to make informed choices without giving up the game they enjoy.

How Are Golfers Exposed to Chemical Exposures?

Golfers can come into contact with pesticide residues in a few ways while they’re on the course. Skin contact is one of the most direct routes, especially when your hands, legs, shoes, or clothing brush against treated grass. You can also inhale pesticides as fine droplets, vapors, or dust, especially during or soon after an application.

Your hands can do more than swing a club on the course. They can act as a pathway for pesticide chemicals to enter your body. If residues get on your skin, you can accidentally swallow them by eating, drinking, smoking, or touching your mouth before washing.

One study found that golfers could pick up measurable amounts of chlorpyrifos and carbaryl after playing on treated turf, mostly through skin contact [34]. The amounts measured were below the EPA’s short-term safety limits at the time, but the study only looked at two pesticides and exposure from a single round of golf. Besides, many harmful chemicals have been shown to have adverse effects, even at small doses.

The good news is that a few simple habits can reduce unnecessary contact. Avoid freshly treated areas, wash your hands before eating or drinking, watch for posted application or re-entry notices, and keep golf shoes and other turf-contact gear out of your main living space when you get home. Golf-course workers may have more frequent and direct exposure, so protective equipment and safe handling practices are especially important for them.

Golf Course Workers: Protection from Pesticide Exposures

For golf course workers, pesticide exposure can look very different from an occasional round of golf. Groundskeepers and applicators may work around treated turf day after day and may also mix, load, or spray concentrated products. Research on greenspace workers has linked pesticide exposure with higher risks of Parkinson’s disease and several cancers, although researchers are still working to identify which chemicals and exposure levels contribute most to those findings.

Wear Protective Gear

Protective gear is one of the most direct ways to reduce exposure. Chemical-resistant gloves should match the pesticide label. Nitrile is commonly used, but the right glove material depends on the product. Respiratory protection also needs to match the chemical.

An N95 can filter particles and some spray mist, but it does not protect against pesticide gases or vapors. When vapor protection is required, workers may need a NIOSH-approved respirator with the correct chemical cartridge, often combined with a particulate filter. The pesticide label should determine the respirator, and workers using tight-fitting respirators should receive proper fit testing and training.

Know Your Chemical Exposures

Stay alert to what is being applied and where. Check posted treatment notices and ask for the pesticide label or application information before entering recently treated areas.

Posting requirements differ by state and pesticide, so if you believe required notices are missing or you are unsure whether an area is safe to enter, bring it up with your supervisor or safety manager rather than guessing. EPA requires pesticide handlers to have access to label information and instructions about hazards, protective equipment, and safe handling.

A respectful way to start that conversation could be, “I want to make sure I’m following the right safety precautions. Can you let me know what was applied here, when it was sprayed, and whether there is a re-entry period or PPE I should be using?”

Clean Up Before Heading Home

Finally, try not to bring the course home with you. Change out of work clothes and shoes before getting into your car or entering your living space when possible. Keep contaminated work clothing separate from household laundry.

If your workplace has locker rooms and showers, consider showering and changing before leaving after pesticide-handling work. EPA guidance also says not to take contaminated PPE home and to store and clean it separately from personal clothing.

Your body already has built-in systems, including the liver and kidneys, that help process and remove chemicals. A practical way to support them is to lower the amount of exposure coming in when you can.

If you live near a golf course, a water filter and air purifier can be useful additions at home. A HEPA filter can reduce particles in the air, while activated carbon can help capture some chemical vapors and contaminants that HEPA alone may miss.

How to Support Your Health Near a Golf Course

If you live or work near a golf course, moving or changing jobs may not be realistic. That doesn’t mean you are out of options! A more practical approach is to focus on the exposures you can reduce.

At home, that may mean:

Using a quality water filter for PFAS and other harmful chemicals
Improving indoor air with a HEPA purifier plus activated carbon
Removing shoes at the door
When possible, keeping windows closed during nearby pesticide applications

It can also help to look at your total chemical load, not just golf-course pesticides. Personal care products, cleaning products, fragrances, plastics, and other everyday items can add to the exposures your body is already processing. Million Marker’s Exposure Test can measure certain chemical metabolites and provide personalized recommendations to help you identify where changes may have the biggest impact.

Always remember to start with the chemicals closest to home! Avoid chemical pesticides on your lawn, garden, and indoor spaces to reduce direct exposures you can control. You may not be able to change where you live or work, but you can still lower your overall chemical burden by making thoughtful changes in the places and products you interact with every day.

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