Rotenone and Public Health
The federal Environmental Protection Agency (EPA) controls pesticide use in partnership with state agencies. Before allowing application of a pesticide, the EPA studies each one to be sure they do not pose risks to human health and the environment.
The EPA regularly reviews all pesticides. In 2007, rotenone was re-registered for use in fish management. In their re-registration assessment, the EPA concluded that using rotenone according to product label instructions does not pose unreasonable risk to human health or the environment. However, the EPA does recommend precautionary measures such as wearing protective clothing for the applicators and closing water bodies treated with rotenone to swimming for a few days following treatment. The World Health Organization classifies rotenone as moderately hazardous because it may be absorbed by ingestion or inhalation. Inhalation of concentrated rotenone in the powder form is the most direct threat to humans, and caution is required during handling. The Alaska Department of Environmental Conservation requires that rotenone applicators receive state certification in applying pesticides.
There is a lot of information currently available concerning rotenone and human health and safety issues. Much of this information is synthesized in the following websites:
Millions of dollars have been spent in the U.S. on research to evaluate the safety of rotenone, and the majority of this work has focused on human health questions. Results of these studies confirm that rotenone does not cause birth defects, reproductive dysfunction, gene mutations or cancer. No fatalities in humans have been reported in response to proper use of rotenone products. Drinking rotenone poses little risk to humans because of the low concentration used and rapid degradation in the aquatic environment. A 160-pound adult would have to drink 23,000 gallons, and a 22-pound child would need to drink over 1,400 gallons of rotenone-treated water at one sitting to receive a lethal dose at concentrations used for fish management. Though rotenone-killed fish are not unsafe to eat, the EPA does not recommend that rotenone-killed fish be used for human consumption because no tolerance (acceptable residue level permitted in fish flesh) has been set by the EPA. In addition, there can be bacterial concerns with the fish because it often takes awhile for them to surface following treatment.
There have been highly publicized concerns that rotenone exposure could be linked to Parkinson's disease, but this linkage has since been refuted. In a study in which rats were injected with rotenone for a period of several weeks, researchers reported finding symptoms characteristic of Parkinson's disease. However, these results have been challenged on the basis of methodology: (1) that the continuous intravenous injection method used by researchers leads to "continuously high levels of the compound in the blood," and (2), that dimethyl sulfoxide (DMSO) was used to enhance tissue penetration whereas normal routes of exposure actually slow introduction of chemicals into the bloodstream. Finally, injecting rotenone into the body or feeding rotenone to lab animals is not a normal way of assimilating the compound, and does not reflect actual exposure conditions during a rotenone treatment for fisheries management.