Environmental Health Risks

• Trained dogs were able to detect Parkinson’s disease from skin swabs with up to 80% accuracy.
  

• This method could lead to a faster, non-invasive way to diagnose the disease earlier.
  

• Researchers hope it could eventually help spot Parkinson’s years before symptoms appear.
  

What if a dog’s nose could help doctors diagnose Parkinson’s Disease (PD)? 

That’s exactly what new research from Medical Detection Dogs and the Universities of Bristol and Manchester has explored. 

In a recent study, two specially trained dogs were able to sniff out Parkinson’s with high accuracy, using nothing more than skin swabs from participants.

While we often associate medical detection dogs with things like cancer or diabetes, this study brings us one step closer to using man’s best friend as a tool in identifying neurological diseases — especially those like Parkinson’s that are notoriously hard to catch early.

“We are extremely proud to say that once again, dogs can very accurately detect disease,” Medical Detection Dogs CEO and Chief Scientific Officer Claire Guest said in a news release. 

“There is currently no early test for Parkinson’s disease and symptoms may start up to 20 years before they become visible and persistent, leading to a confirmed diagnosis. Timely diagnosis is key as subsequent treatment could slow down the progression of the disease and reduce the intensity of symptoms.”

The study

The star dogs — Bumper the Golden Retriever and Peanut the Labrador — were trained over several weeks using more than 200 skin swab samples. 

The samples came from two groups: people with Parkinson’s disease and those without. During training, the dogs learned to pick out the scent associated with Parkinson’s and were rewarded when they correctly identified positive samples — or correctly ignored the ones that didn’t show signs of the disease.

For the actual testing phase, researchers used a “double-blind” method. That means even the handlers didn’t know which samples were which — only a computer did. 

Each row of samples was presented in different orders, and any samples the dogs didn’t respond to were reshuffled and re-presented until a decision was made for every single one.

The results

The dogs showed up to 80% sensitivity (correctly identifying positive cases) and up to 98% specificity (correctly ignoring negative ones). 

Even more noteworthy? The dogs were still able to detect Parkinson’s even when patients had other unrelated health conditions, suggesting the scent they were picking up on is very specific to the disease.

There’s still no definitive test for Parkinson’s, and symptoms can take years — even decades — to fully show up. That’s why early detection tools like this have so much promise. 

“Identifying diagnostic biomarkers of PD, particularly those that may predict development or help diagnose disease earlier, is the subject of much ongoing research,” researcher Nicola Rooney said in the news release. 

“The dogs in this study achieved high sensitivity and specificity and showed there is an olfactory signature distinct to patients with the disease. Sensitivity levels of 70% and 80% are well above chance, and I believe that dogs could help us to develop a quick non-invasive and cost-effective method to identify patients with Parkinson’s disease.”

• EWG study shows tackling several tap water contaminants at once offers far greater health benefits than treating pollutants individually.

• Arsenic and chromium-6 frequently occur together and can be reduced using the same technologies.

• Small and rural communities face the highest risks and costs, underscoring a call for updated federal regulations.

A new study suggests that changing how America treats contaminated drinking water could save tens of thousands of lives. Instead of tackling one pollutant at a time, water systems should adopt multi-contaminant treatment strategies that can significantly reduce cancer risks nationwide, according to research published by the Environmental Working Group (EWG) in the journal Environmental Research.

The peer-reviewed study analyzed more than a decade’s worth of data from over 17,000 community water systems. EWG scientists found that simultaneously targeting dangerous chemicals like arsenic and hexavalent chromium, also known as chromium-6, could prevent more than 50,000 lifetime cancer cases in the U.S. Chromium-6 alone has been detected in water supplies serving about 251 million Americans.

“Drinking water is contaminated mostly in mixtures, but our regulatory system still acts like they appear one at a time,” said Tasha Stoiber, Ph.D., EWG senior scientist and lead author of the study. “This research shows that treating multiple contaminants together could prevent tens of thousands of cancer cases.”

Higher risk where pollution overlaps

Arsenic and chromium-6 frequently co-occur in drinking water systems and can be removed using similar technologies like reverse osmosis and ion exchange. The study found that reducing arsenic levels by as little as 27% to 42% in systems already dealing with chromium-6 contamination could quadruple the number of cancer cases avoided compared to treating chromium-6 alone.

States like California, Arizona, and Texas face the highest burden from arsenic pollution and would benefit most from a multi-contaminant approach. In California alone, nearly eight out of 10 preventable cancer cases linked to drinking water are due to arsenic exposure.

Health risks from these pollutants are particularly severe for children, pregnant people, and residents in small or rural communities, which often rely on groundwater and lack resources to upgrade outdated water systems.

Outdated regulations and cost challenges

Under current regulations, the federal government evaluates each contaminant in isolation, considering costs and benefits pollutant by pollutant. But EWG researchers argue this approach is outdated and leaves millions vulnerable to cumulative health risks from chemical mixtures in drinking water.

“The federal nitrate limit was set decades ago to prevent infant deaths, but we now know cancer and birth complications can occur at much lower levels,” said Anne Schechinger, EWG’s Midwest director.

Nitrate contamination, particularly common in agricultural regions, poses significant health risks including cancer and birth defects. EWG estimates that cutting nitrate levels by just 20% could prevent 130 cancer cases each year and save $35 million in healthcare costs, especially when combined with treatment for arsenic and chromium-6.

Despite proven technologies capable of removing multiple pollutants at once, small water systems face steep costs and limited technical support, leaving many communities exposed to significant health risks.

“This is about more than clean water—it’s about protecting health and advancing equity,” said David Andrews, Ph.D., acting chief science officer at EWG. “We have the engineering solutions to fix the broken drinking water system in the U.S., but we need state and federal policies to reflect the reality people face when they turn on the tap.”

What consumers can do

While policymakers debate reforms, consumers worried about tap water contaminants can take steps to protect themselves. EWG recommends reverse osmosis filters for removing arsenic, chromium-6, and nitrate, though filters must be replaced on schedule to stay effective.

Consumers can also search EWG’s Tap Water Database to learn which contaminants are present in their local water systems.

As concerns grow about drinking water safety across the country, experts say a shift toward multi-contaminant solutions could be key not only to preventing cancer cases but also to promoting health equity and saving millions in healthcare costs.