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Assessing Pesticide Cumulative Risk
Quick Resources
This website provides information on EPA's
- process for conducting pesticide cumulative risk assessments,
- cumulative risk assessment methods and tools, including several exposure assessment models, and
- cumulative risk assessments for four
groups of pesticides,
- Organophosphates (OPs)
- N-methyl carbamates
- Triazines
- Chloroacetanilides
Through the pesticide reregistration program, EPA evaluates the risks of individual, older pesticides to human health and the environment. Under the Food Quality Protection Act (FQPA), the Agency also must assess the cumulative risks of pesticides that share a common mechanism of toxicity, or act the same way in the body.
EPA has developed a framework for conducting cumulative risk assessments. In assessing cumulative risks, EPA evaluates the potential for people to be exposed to more than one pesticide at a time from a group with an identified common mechanism of toxicity. These cumulative assessments consider exposures from food, drinking water, and residential sources. The Agency also incorporates regional exposures from residential and drinking water sources since this is the most appropriate way to account for the considerable variation in potential exposures across the country. EPA's cumulative assessments, therefore, approximate as closely as possible people's actual exposures and potential risks resulting from current uses of these pesticides in different parts of the country.
The Agency has determined so far that four groups of pesticides each have a common mechanism of toxicity and require cumulative risk assessments because exposure to these pesticide groups may pose potential risks to human health and the environment. The four groups are: the organphosphates, N-methyl carbamates, triazines and chloroacetanilides.
The Agency has determined that two other groups of pesticides, the thiocarbamate and dithiocarbamate pesticides, should not undergo cumulative assessments since chemicals in those two groups do not act the same way in the body. In late 2001 and early 2002, EPA provided an opportunity for the public to comment on the Agency's common mechanism determinations for the thiocarbamates (PDF) (46 pp, 348 KB, About PDF) and dithiocarbamates (PDF) (51 pp, 418 KB, About PDF), which also belong to the carbamate group of pesticides. EPA considered four common effects, including acetyl cholinesterase inhibition, and determined that the thiocarbamates and dithiocarbamates do not share a common mechanism of toxicity.
Through cumulative risk assessment, EPA will be able to consider whether the risks posed by a group of pesticides that act the same way in the body meet the current safety standard of "reasonable certainty of no harm" established by FQPA. Pesticides that EPA determines meet this standard may successfully complete tolerance reassessment under the Federal Food, Drug, and Cosmetic Act, now closely intertwined with completing reregistration under the Federal Insecticide, Fungicide, and Rodenticide Act. During development of the individual and cumulative assessments and the subsequent risk management decisions, EPA provides a number of opportunities for input from stakeholders. The Agency's process for public involvement and consultation during EPA's tolerance reassessment and reregistration review of pesticides is outlined on a separate web page.