Advisory panel affirms: Strict Game and Fish procedures assure that rotenone is a safe, effective fisheries management tool
Game and Fish Director approves final report and process improvement recommendations
PHOENIX – A blue-ribbon committee that extensively studied the use of rotenone in Arizona has reaffirmed the Arizona Game and Fish Department’s belief that rotenone is an important fisheries management tool that can be used safely and effectively.
Rotenone is a piscicide (a pesticide used to kill undesired fish) that is used in limited applications to assist native fish and aquatic species recovery or aquatic invasive species control.
The report and recommendations from the Rotenone Review Advisory Committee were accepted and approved on Jan. 9, 2012 by Game and Fish Director Larry Voyles.
“The committee provided insightful analysis and a number of recommendations regarding the department’s piscicide application procedures,” said Voyles. “The results show once again that processes can always be improved by careful evaluation and input from experts in different fields. We’ve just made processes and procedures that were very good even better.”
Voyles added that in addition to the committee recommendations, and after taking into careful consideration the recommendations by the Arizona Farm Bureau, “I have directed this agency to meet the standards of the National Environmental Policy Act for all piscicide applications.”
The use of rotenone as a piscicide prompted concerns last year by some constituents over perceptions of potential environmental or human health impacts from exposure. The concerns resulted in proposed state legislation—SB1294 and HB2114—that would have virtually eliminated the Arizona Game and Fish Department’s ability to use rotenone in the future. The legislation did not pass last session.
To thoroughly study the issue and address constituent concerns, Voyles temporarily halted the Game and Fish Department’s use of rotenone in Arizona and in June authorized the formation of the Rotenone Review Advisory Committee to analyze and make recommendations on the use of rotenone and other piscicides for Arizona fisheries and aquatic wildlife management.
The committee and its composite subcommittees reviewed the best available scientific reports and research, gathered input from other experts, and provided technical expertise, opinion, and analysis regarding the use of rotenone and other piscicides, focusing on the following subject areas: (1) state/federal regulations, internal policy, public involvement, and best management practices; (2) human health and the environment; (3) alternate management strategies; and (4) recreational, economic and social impacts.
The committee presented its final recommendations to the director in November, and the final report in late December. Among the recommendations, many of which are already in practice by Game and Fish, are:
- Modify policies and procedures for the planning and implementation of rotenone piscicide projects in Arizona in accordance with the latest accepted standards and regulations, which minimize potential environmental impacts and avoid impacts to human health and drinking water supplies.
- Include a robust public engagement process by developing a public awareness or involvement plan during planning and implementation of each piscicide project.
- Develop a project-specific operating protocol when there is a known or suspected direct connection with groundwater wells and rotenone-treated water within the project area.
- Ensure appropriate training for handling and applying rotenone to minimize human and non-target species exposure.
- Monitor scientific literature to ensure policies and practices take into account any advances in science and knowledge.
- Recognize the recreation, economic and social value of having rotenone as a tool to manage fish populations, and have the ability to use rotenone in a manner consistent with the latest Environmental Protection Agency (EPA) approved application procedures.
One of the concerns the committee examined was whether there was an association between rotenone exposure and Parkinson’s disease, in light of some recent studies that received media coverage.
The committee found that, to date, there are no published studies that conclusively link exposure to rotenone and the development of clinically diagnosed Parkinson’s disease. It found that the studies using animal models and pesticides to investigate the pathway of Parkinson’s disease are limited in scope because they do not produce the actual disease state, and they model only the motor features of the disease. Further, they used very high doses of rotenone administered to rodents mostly through tissue injection over long time periods—methods not relevant to realistic human exposure.
Other studies focused on rotenone use as an insecticide in the agricultural field, primarily applied by farmers. None of the studies identify risks from the application methods (insecticide or piscicide), or address the differences in rotenone concentrations that vary with application methods. Very small concentrations of rotenone are used in fish management in accordance with EPA-required protocols.
Piscicidal use of rotenone as a restricted-use pesticide degrades quickly, has never been shown to contaminate groundwater without a direct connection to the treated surface water, and restricts human exposure of the treatment area during treatment, all of which make an environmental exposure to rotenone highly unlikely to cause Parkinson’s disease or Parkinson’s-like symptoms in humans.
A detailed examination of this and other human health and environmental aspects are included within the committee’s report.
Participating members of the committee included representatives from the Arizona Department of Environmental Quality, Arizona Department of Health Services, Arizona Department of Water Resources, Arizona Department of Agriculture, Arizona Game and Fish Department, Arizona House of Representatives, Arizona Senate, Arizona State University, Central Arizona Project, City of Phoenix, Salt River Project, U.S. Environmental Protection Agency, U.S. Forest Service, U.S. Fish and Wildlife Service, Bureau of Land Management, Arizona Farm Bureau, Arizona Wildlife Federation, Trout Unlimited, R and R Partners, Shuler Law Firm, Town of Patagonia, and the Institute for Environmental Conflict Resolution.
Background on rotenone
Rotenone is a naturally occurring substance derived from the roots of tropical plants in the bean and pea family that are primarily found in Malaysia, South America, and East Africa. People have used rotenone for centuries to capture fish for food in areas where these plants are naturally found, and it has been used in fisheries management as a piscicide (a pesticide used to kill undesired fish) in North America since the 1930s. Rotenone was originally registered in the U.S. in 1947 for use in agriculture and as a piscicide. It was reregistered by EPA in 2007 for piscicide use after an extensive review of human and environmental safety.
Rotenone is an important tool for removing competing and predatory non-native fish from small, targeted recovery areas so that native fish or frogs (including threatened and endangered species) can be restored. Use of this tool is important to the state’s native and threatened/endangered species conservation efforts, which help ensure multiple uses of land as well as continued sport fishing opportunities and their associated economic benefits to the state. Rotenone is also used to control invasive species that can cause environmental and economic harm.
Rotenone does not persist long in the environment. Because it degrades rapidly, it disappears from streams quickly and does not penetrate well through soil, and therefore does not pose a threat to groundwater. In fact, short- and long-term monitoring studies following rotenone treatments have never detected rotenone in groundwater wells that have no direct connection to rotenone-treated surface water.
Humans and mammals are not affected by the small concentrations of rotenone used in fish removal projects. There are no known health impacts to humans when rotenone is used according to directions on the EPA-approved rotenone product labels.