By Nathan Donley, Center for Biological Diversity, July 2016
More than 1 billion pounds of pesticides are used in the United States each year, applied to agricultural fields and orchards, residential lawns, playgrounds and parks. Pesticides are often mixed with other pesticides and chemicals before application or after, and the individual ingredients in these mixtures can interact in such a way as to enhance their toxic effects. This is referred to as “synergy,” and it can turn what would normally be considered a safe level of exposure to people, wildlife and the environment into one that causes considerable harm.
Although pesticide mixtures in the environment have been extensively documented, the Environmental Protection Agency generally only assesses the toxicity of pesticides individually, in isolation from potential real-life scenarios where these pesticides may interact with other chemicals. The EPA, which is tasked with ensuring that pesticides do not result in unreasonable harm to human health and the environment, often rationalizes this approach by stating that studies measuring mixture toxicity are often not available for analysis.
Our analysis, however, contradicts that claim by utilizing a publicly available information source (data from the U.S. Patent and Trademark Office) that provides a disturbing snapshot of pesticide synergy and the potential for widespread danger to people, waterways and wildlife — risks the EPA has repeatedly failed to identify and consider during its approval process.
For this report we conducted an intensive search of patent applications that were germane to all pesticide products containing two or more active ingredients approved by the EPA in the past six years from four major agrochemical companies (Bayer, Dow, Monsanto and Syngenta).
Among our key findings:
• 69 percent of these products (96 out of 140) had at least one patent application
that claimed or demonstrated synergy between the active ingredients in the
• 72 percent of the patent applications that claimed or demonstrated synergy
involved some of the most highly used pesticides in the United States, including glyphosate, atrazine, 2,4-D, dicamba and the controversial neonicotinoids thiamethoxam, imidacloprid and clothianidin, among others, indicating that potential impacts could be widespread.
This suggests that synergistic action between pesticide active ingredients is much better documented and more common than current EPA pesticide assessments would indicate. Further, it appears that pesticide companies are in fact collecting information about the synergistic effects of their products that they are not sharing with the EPA. Recognizing that pesticide synergy data are widely available and that the synergistic relationships between pesticides can have serious implications for human and environmental health, the EPA must now take action to properly consider the potential consequences of pesticide synergy.
For the full PDF version of the report click here.