Paraquat Exposure May Damage Neurons, Lead to Parkinson’s Disease: New Study

Paraquat, a widely used herbicide in the United States, has come under increasing scrutiny in recent years due to its potential link to Parkinson’s disease, a debilitating neurological condition. Decades of research has uncovered a troubling connection between exposure to paraquat and the development of this chronic, progressive brain disorder, including one new study in which researchers found that exposure to the weed killer paraquat damages neurons in a way that may lead to Parkinson’s disease. 

As the number of paraquat-related Parkinson’s disease claims continues to rise, affected individuals and their families are seeking justice, filing lawsuits against Syngenta and other paraquat manufacturers for their alleged failure to adequately warn about the risks.

What is Paraquat?

Paraquat is a highly potent herbicide that has been a staple in the agricultural industry for decades, prized for its effectiveness in controlling weeds and grasses. However, this same potency that makes it a valuable tool for farmers also renders it extremely hazardous to human health. Paraquat is classified as a “toxic chemical” by the Centers for Disease Control and Prevention (CDC), and even a small amount ingested can result in fatal poisoning.

Despite these well-documented risks, paraquat remains approved for use in the United States, where it is sold under various brand names such as Gramoxone, Firestorm, Helmquat, and Parazone. The herbicide is commonly used as a substitute for the glyphosate-based weed killer Roundup, which has faced its own legal battles due to concerns over its highly publicized link to non-Hodgkin’s lymphoma and other cancers.

Paraquat Exposure Pathways and Health Consequences

The primary concern surrounding paraquat is not just its acute toxicity, but also the long-term health effects associated with chronic exposure. Even when used as directed, the herbicide can pose a serious threat to the health of agricultural workers, farmers, landscapers, and others who come into contact with it during mixing, loading, or application.

According to the CDC, inhalation or skin absorption of paraquat can lead to a range of devastating health consequences, including lung damage, heart failure, and kidney failure. The CDC also warns that paraquat exposure can cause esophageal strictures, a condition where the esophagus narrows, making it difficult to swallow.

Potential Link Between Paraquat and Parkinson’s Disease

The connection between paraquat exposure and Parkinson’s disease has been the subject of extensive research, with numerous studies pointing to a clear correlation between the two. The Agricultural Health Study, a landmark prospective study involving over 52,000 licensed pesticide applicators, found that those exposed to paraquat had double the risk of developing Parkinson’s disease compared to non-users.

In one of the latest paraquat studies, published last month in the journal Ecotoxicology and Environmental Safety, researchers reported that exposure to paraquat may result in the abnormal accumulation of a protein called α-synuclein (α-syn), which the brain then cannot eliminate efficiently. According to the study authors, the buildup of this protein is linked to neurodegenerative diseases like Parkinson’s disease.

“The lack of amyloid clearance is now widely recognized as one of the important etiologies of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases,” the researchers noted. “Epidemiological studies and rodent experiments have shown that [Paraquat] is associated with Parkinson’s disease and causes typical pathological changes such as misfolding of soluble α-syn monomers into insoluble aggregates that are difficult to degrade.”

Regulatory Efforts and Ongoing Paraquat Lawsuits

In response to the growing body of evidence linking paraquat to Parkinson’s disease, regulatory agencies have taken some steps to address the issue. In 2016, the U.S. Environmental Protection Agency (EPA) introduced measures to minimize the risk of accidental paraquat ingestion and reduce exposure among pesticide applicators and farmworkers. These included restricting the use of paraquat to certified applicators only and requiring specialized training.

However, critics argue that these efforts fall short of adequately protecting the public from the alleged neurological dangers posed by paraquat. The Unified Parkinson’s Advocacy Council has expressed concern that restricting use to certified applicators is “insufficient to protect all people,” as paraquat exposure can also occur through herbicide drift and residue in rural communities.

Thousands of Paraquat Lawsuits Filed Nationwide

Thousands of individuals across the United States have filed lawsuits against Syngenta, Chevron, and other paraquat manufacturers, alleging that the companies failed to adequately warn about the neurological risks associated with paraquat exposure, putting agricultural workers, farmers, and nearby residents at risk of developing Parkinson’s disease.

The federal paraquat litigation, which includes more than 5,000 lawsuits, has been centralized in the U.S. District Court for the Southern District of Illinois as part of a multidistrict litigation (MDL) process. This consolidation of claims is intended to streamline the legal proceedings and facilitate the resolution of common issues. The first bellwether trial, which will serve as a test for the broader litigation, is scheduled to begin in November 2022.