PMRA premature in re-registering 2,4-D
By Dr. Meg Sears, Ottawa Adjunct Investigator, CHEO Research Institute
July 14, 2008
Canada's re-registration of the weed killer 2,4-D disallows some products, decreases application rates, and increases applicator protection. Past practices were unsafe. Has the Pest Management Regulatory Agency (PMRA) now got it right?
In 2006, I was among researchers and physicians who concluded in Paediatrics and Child Health that "2,4-D can be persuasively linked to cancers, neurological impairment and reproductive problems." Subsequent peer-reviewed research strengthens this conclusion. The PMRA decision is premature. Manufacturers have yet to provide important studies.
Scientific reports of birth defects and neurological harms have not factored in the PMRA decision, but animal studies coming in 2009 may trigger further measures to protect children. Contaminant analyses are also pending. According to Environment Canada, herbicides like 2,4-D are the largest source of 2,7-DCDD (the unregulated dioxin that comes with 2,4-D) in our environment. PMRA staff say that vastly more 2,7- DCDD than regulated dioxins is in 2,4-D. Importantly, given its high levels, the U.S. Agency for Toxic Substances and Disease Registry found that 2,7-DCDD is "equipotent" to the most toxic, regulated dioxin, in tests of immune suppression.
Immune disruption contributes to many chronic illnesses, including cancers. The PMRA quietly let slide the 2005 Advisory Panel recommendation to investigate further child cancer. The immune system cancer non-Hodgkin lymphoma (nHL) is strongly linked to 2,4-D. The PMRA dismissed these scientific studies, and even misinterpreted one as saying that 2,4-D lowered the chance of developing a particular nHL. In fact, compared to farmers not using pesticides, applicators of 2,4-D were three times as likely to develop the cancer.
The National Cancer Institute of Canada says that North America is a world leader in nHL. The 2,4-D-linked nHL is increasing most rapidly, and is the most intractable to treat.
When pesticides are used in neighbourhoods, children's largest exposure may be from dust. Bylaws and provincial legislation for least- toxic pest control, to eliminate this exposure, are wise public policy.
Based upon these concerns, and additional information gathered during 2 days spent examining the confidential data available in the Reading Room at the PMRA, an objection to the 2,4-D re-registration was submitted.
Meg Sears,
Ottawa Adjunct Investigator,
CHEO Research Institute
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