Foodexposed has previously discussed the EPA approval of 2,4-D and its combination with glyphosate to produce a new herbicide product. A new genetically modified product was recently approved by the USDA despite vociferous protest from environmental groups, concerned scientists and medial professionals and grassroot activists.
The International Agency for Research on Cancer (IARC) has classified the popular herbicide, 2,4-D, as a Group 2B, “possibly carcinogenic to humans.” Twenty six experts from 13 countries met at the World Health Organization’s (WHO) IARC in Lyon, France to assess the carcinogenicity of the insecticide lindane, the herbicide 2,4-D, and insecticide DDT. Glyphosate, the ingredient in the popular Roundup weed killer, has been previously classified as a Group 2A “probable” carcinogen, by the IARC based on sufficient evidence of carcinogenicity.
“Exposures to herbicides in early life can lead to disease in childhood or disease later on in adult life or even old age,” said Dr. Landrigan, dean for global health at Mount Sinai School of Medicine. “Herbicide chemicals can also cross from mother to child during pregnancy and prenatal exposures that occur during the nine months of pregnancy are especially dangerous.”
“Physicians are very concerned about exposure to the combination of 2,4-D and glyphosate because of the potential lifelong and irreversible effects on the health of vulnerable populations, including children, pregnant women and farm workers,” said Dr. Thomasson, executive director of Physicians for Social Responsibility. “Policy decisions should take into account the costs that can result from failure to act on the available data on toxic herbicides.”
“2,4-D already is permitted by EPA to remain as residues on over 300 different forms of food,” said John P. Wargo, Ph.D., professor of environmental health and politics at Yale University. “Spraying millions of additional acres with these chemicals will increase their contamination of soils, surface and groundwater and foods bearing their residues. If applied by aircraft, sprays will drift to adjacent lands, potentially endangering those who reside, go to school or work nearby.”
“There is strong evidence that 2,4-D induces oxidative stress, a mechanism that can operate in humans, and moderate evidence that 2,4-D causes immunosuppression, based on in vivo and in vitro studies. However, epidemiological studies did not find strong or consistent increases in risk of NHL or other cancers in relation to 2,4-D exposure.”
In the review conducted by IARC experts, population-based case-control studies of 2,4-D exposure in relation to lymphoma and leukemia were found to provide mixed results. The working group conducted a meta-analysis of 11 studies that shows no association of non-Hodgkin lymphoma with over-exposure to 2,4-D, although the results appeared to be sensitive to whether the studies adjusted for other pesticides. The consensus of the working group was that there is inadequate evidence in humans for the carcinogenicity of 2,4-D, although a substantial minority considered that the evidence was limited. But in animal studies, the group finds that there was limited evidence in experimental animals for the carcinogenicity of 2,4-D, due to methodological concerns regarding the positive studies. Many of the studies under review observed increased incidence of reticulum-cell sarcoma in laboratory mice. In male rats, 2,4-D in the diet induced a positive trend in the incidence of rare brain cancer tumors (astrocytomas). However, other studies provided strong evidence that 2,4-D induces oxidative stress that can operate in humans and moderate evidence that 2,4-D causes immunosuppression, based on in-vivo and in-vitro studies.
2,4-D, one half of chemical makeup of Agent Orange, is highly toxic as it is linked to numerous adverse health effects, including increased risk of birth defects, reduced sperm counts, Parkinson’s disease, and endocrine disruption. Unfortunately, its use is predicted to increase due to the deregulation and expected proliferation of 2,4-D tolerant genetically engineered (GE) crops. Concerns around increased 2,4-D use on GE crops revolves around increasing the onset of 2,4-D-resistant weeds, direct and indirect adverse impacts on human health, increased in drift to non-target sites, and the contamination of food and water. Earlier this year, several conservation, food safety, and public health groups filed a motion challenging the EPA’s decision to expand the use of a new 2,4-D product to be used on GE crops citing serious impacts the powerful new herbicide cocktail will have on farmworkers, neighboring farms, and ground and surface water, as well as endangered species.
The use of 2,4-D also comes with the possibility for dioxin contamination, which has been a long part of 2,4-D’s history. Expected increases in 2,4-D use means that the frequency of low level dioxin residues entering the environment may also increase. Dioxins are a carcinogenic class of chemicals that have left a toxic legacy for human health and environmental protection across the U.S due to their persistence and toxicity. Dioxins have notoriously long half-lives, are bioaccumulative, and present broadly significant health risks developmentally and postnatally.