Paraquat and Parkinson’s Disease

In recent months, growing concerns about the relationship between paraquat exposure and Parkinson’s disease have gained attention in the Australian media.

Paraquat, a commonly used herbicide since the 1960s, is currently the active ingredient in 141 products registered by the Australian Pesticides and Veterinary Medicines Authority (APVMA). While banned in many countries due to its toxicity, paraquat remains legal in Australia.

In early September 2024, ABC Landline aired a program addressing concerns about paraquat and its potential link with Parkinson’s disease. These concerns were raised by both scientists and farmers. Animal studies have suggested that exposure to paraquat may lead to the destruction of dopamine neurons in the brain, which had previously been identified as a key factor in Parkinson’s disease. One study found that Parkinson’s disease was more prevalent in rural and remote areas, such as farming communities. Several independent studies also found evidence linking paraquat exposure to an increased likelihood of developing Parkinson's disease. However, both Syngenta, the original manufacturer of paraquat, and the APVMA have maintained that there is insufficient evidence to link the chemical to the disease, asserting that it is safe when used correctly. Such statements by Syngenta appeared to contradict their internal findings. When the program was aired, the APVMA had already released a draft review of paraquat, which was still open for consultation. This draft review included new safety restrictions and stricter protective measures.

Shortly after the program aired, ABC News reported that Parkinson’s Australia, the Australian advocacy group for the neurodegenerative disease, had called for a ban on paraquat. The petition coincided with the APVMA’s review of the chemical, and is still open. In addition to Parkinson’s Australia’s concerns, the Australian Council of Trade Unions (ACTU) raised their own concerns. In particular, the ACTU was concerned that the APVMA was more focused on industry interests rather than those of the people who were more likely to be exposed to the chemical, urging the regulator to work more closely with such stakeholders when making their decisions.

In response to ABC Landline and ABC News, the APVMA released a media statement correcting claims they felt misrepresented the APVMA’s position and the current scientific consensus on paraquat. The APVMA emphasized that their review of the chemical was still open for consultation, and that all submissions would be considered. They clarified that they consider a wide range of studies, including independent research, and make decisions based on the available evidence. The APVMA noted that they do not consider animal studies on paraquat to be relevant to typical human exposure, as they involve unrealistic occupational exposure methods. Furthermore, they emphasized that product safety is evaluated under the assumption that the product in question is used in accordance with recommended safety measures, as per the product label. Regarding claims that there is a growing body of evidence linking paraquat to Parkinson’s disease, the APVMA highlighted that their reviews, as well as those conducted by the US Environmental Protection Agency, do not support such claims. The APVMA requested that ABC issue a correction to clarify these points.

Before the airing of the ABC Landline program, Syngenta had already released a statement, in which they affirmed that the paraquat is safe when used as directed, and that current scientific studies do not support a link between herbicide and Parkinson’s disease. After the program aired, Syngenta released a follow-up statement, echoing the APVMA’s view that ABC Landline and ABC News had misrepresented their stance. They reiterated that paraquat is safe to use, and the links between the chemical and disease are not supported by current scientific studies.

The APVMA’s public consultation on paraquat has since closed, having received submissions from industry, community, medical and public health sectors. They assured the public that a rigorous scientific assessment will be completed, and that all evidence provided will be carefully considered. However, should new evidence emerge showing an imminent risk to human health, the APVMA will take swift action to protect those potentially exposed to the chemical. A final decision on paraquat is expected to be published in mid-2025.