Rotenone is an odorless chemical that is used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the roots and stems of several plants such as the jicama vine plant. It causes Parkinson's disease-like symptoms if injected into rats. Rotenone kills the freshwater snail Lymnaea stagnalis by attacking the mitochondria in its neurons.
Emmanuel Geoffroy first isolated rotenone from a specimen of Robinia nicou, now called Lonchocarpus nicou, while traveling in French Guiana. He wrote about this research in his thesis, published posthumously in 1895 after his death from a parasitic disease. Researchers later determined that the substance which Geoffroy termed nicouline was identically rotenone.
Rotenone is used in solution as a pesticide and insecticide.
It is commonly used in powdered or emulsified liquid form in fisheries management to remove unwanted fish species, such as the eradication of exotic fish from non-native habitats. People catch fish by extracting rotenone from plants and releasing it into water. Poisoned fish come to the surface and are easily caught. This method was first practiced by various indigenous tribes who smashed the roots. Fish caught this way can be eaten because rotenone is very poorly absorbed by the gastrointestinal tract of humans, whereas it is lethal to fish because it readily enters the blood stream of the fish through the gills.
Small-scale sampling with rotenone is used by fish researchers studying the biodiversity of marine fishes to collect cryptic, or hidden, fishes, which represent an important component of shoreline fish communities. Rotenone is the most effective tool available because only small quantities are necessary. It has only minor and transient environmental side-effects.
Rotenone is also used in powdered form to reduce parasitic mites on chickens and other fowl. In the United States and in Canada, all uses of Rotenone except as a piscicide are being phased out.
Rotenone is classified by the World Health Organization as moderately hazardous. It is mildly toxic to humans and other mammals, but extremely toxic to insects and aquatic life including fish. This higher toxicity in fish and insects is due to the fact that the lipophilic rotenone is easily taken up through the gills or trachea, but not as easily through the skin or through the gastrointestinal tract.
The lowest lethal dose for a child is 143 mg/kg. Human deaths attributed to Rotenone are rare because its irritating action causes vomiting. Deliberate ingestion of rotenone can be fatal.
The compound breaks down when exposed to sunlight and usually has a short lifetime of six days in the environment. In water rotenone may last six months.
Rotenone is classified by the USDA National Organic Program as a nonsynthetic and was allowed to be used to grow "organic" produce until 2005 when it was removed from the list of approved substances due to concerns about its safety
In 2000 it was reported that injecting rotenone into rats causes symptoms of Parkinson's disease to develop. Rotenone was continuously applied over a period of five weeks, mixed with DMSO and PEG to enhance tissue penetration, and injected into the jugular vein.
The study does not directly suggest that rotenone exposure is responsible for Parkinson's disease in humans but is consistent with the belief that chronic exposure to environmental toxins increases the likelihood of the disease.
In addition, studies with primary cultures of rat neurons and microglia have shown low doses of rotenone (below 10 nM) to induce oxidative damage and death of dopaminergic neurons and it is these neurons in the substantia nigra that die in Parkinson's disease.
It had been known earlier that the neurotoxin MPTP causes Parkinson's disease (in humans and other primates, though not in rats) by interfering with Complex I in the electron transport chain and killing dopaminergic neurons in the substantia nigra. Because of this, rotenone was investigated as a possible Parkinson-causing agent. Both MPTP and rotenone are lipophilic and can cross the blood-brain barrier.
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UNDERSTANDING ROTENONE
HELPFUL LINKS
Question and answer about eradication
From Department of Fisheries and Game in California
Millions of dead tui chubs floating atop freshly poisoned Diamond Lake was a specter the Sutten family could not miss Friday.
Matt and Teresa Sutten hauled their three kids from their Springfield home through the year's first snow to the Diamond Lake Resort, where the carnage from Thursday's poisoning ringed the docks and shoreline Friday like thick, silver ruffles.
"It's a massacre," declared their son, Andrew Sutten, 11.
Life after death began Friday at Diamond Lake, when floating mats of dead chubs brought renewed optimism that the 13-year-old fight against invasive species is over here — for now.
State fish biologist Dave Loomis declared Diamond Lake fishless a day after dozens of his fellow Oregon Department of Fish and Wildlife employees donned protective moon suits to apply rotenone that killed all fish in the lake.
The targets were chubs, which were illegally introduced in the late 1980s by fishermen who illegally used them as live bait. Ninety-million chubs later, the lake sported a ramshackle fishery and an ecosystem so damaged by the voracious fish that insects and zooplankton disappeared and were replaced by toxic algae blooms.
After pulling off the $5.6 million project planned and studied the past five years, Loomis and others began preparations for jump-starting the once-popular trout fishery while adding new tools in the fight against unwanted water pests.
Plans are to stock predatory trout as early as next spring as a first line of defense against any unwanted invader that could find its way to this High Cascades lake.
Loomis hopes to have state and federal agencies build at least two boat- and trailer-washing stations that could keep zebra mussels or other non-native marauders from piggybacking into the lake on boats.
A new kiosk and warning signs will anchor an aggressive education program aimed at hammering home the message to anglers: Friends don't let friends use tui chubs as bait.
"Invasive species are a serious problem," said Loomis, who headed the multi-agency restoration team. "We don't want anybody out there to miss the story of Diamond Lake."
For the Suttens, they wanted to be part of the story.
Former Diamond Lake devotees, the family had joined hordes of others who steered clear of the 5-square-mile lake that drew more than 100,000 angler-days before chubs were discovered in 1993.
"When they restock it, we'll be back," Matt Sutten said.
But first, they and others had to see Friday what soon will be missing.
When Forest Service law-enforcement officers dropped the barricades at noon, Dave Swenson of Roseburg came to see the carnage and create his own video journal.
"This is a major event," said Swenson, a science teacher in nearby Oakland. "The whole ecosystem is starting over, and it's awesome."
The water was already safe Friday for swimming and even drinking — at least for wildlife. Loomis calculated that, based on that morning's rotenone levels, a songbird would have to drink 40 gallons of treated water in 24 hours to feel any impacts from the poison.
Still, death was everywhere.
Thousands and thousands of 3- and 4-inch chubs lapped against docks, buoys, breakwaters and rocks. For every 15,000 chubs, Loomis said, he saw one dead trout. A commercial fisherman will skim the dead fish beginning Saturday and haul them to landfills or to farms for fertilizer.
Swenson's hand-held video camera whirred through the wind and snow.
"I'm here to look at dead fish," said Swenson, who will bring 100 seventh- and eighth-graders to the lake Monday to teach a science lesson about invasive species. "I'm psyched."
Snow knocked down any stench of rotting fish while birds feasted at the smorgasbord that Matt Sutten decided he needed to see.
"They poisoned this once (in 1954), so I figured this was the only time in my lifetime that I can see something like this," Sutten said.
His children, however, might get another chance.
ODFW Director Virgil Moore said he believes the war against invasive species is not a winnable one.
"We have all sorts of threats to our ecosystems from invasive species," Moore said.
It could be tui chubs, zebra mussels or hydrilla. Maybe even goldfish. Moore said he expects some invader to make its way intentionally, or accidentally, into Diamond Lake and again upset the ecological balance.
Moore also believes technicians in the future will don moon suits and backpacks full of rotenone and pump death once again into Diamond Lake.
"It's probably not the last time we'll have to do it," Moore said of the rotenone treatment.
"Whether it's 20 years from now or 50 years from now, that's the question."
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Invasive Species Threaten
Salmon In Pacific Northwest
Adapted from materials provided by American Institute of Biological Sciences.
Mar. 2, 2009 - Many native fishes in the Pacific Northwest are threatened or endangered, notably salmonids, and hundreds of millions of dollars are expended annually on researching their populations and on amelioration efforts.
Most of the attention and funding have been directed toward to the impacts of habitat alteration, hatcheries, harvest, and the hydrosystem—the "all H's." A study published in the March 2009 issue of BioScience concludes, however, that nonindigenous species, notably invasive fishes, appear to pose at least as much of a threat to native salmonids as the all H's, principally through predation.
The study, by Beth L. Sanderson of the Northwest Fisheries Science Center in Seattle, Washington and two colleagues, made use of a spatially explicit database that identified the presence of invasive species in roughly 1800-square-kilometer, hydrologically connected areas throughout Washington, Oregon, and Idaho. The number of invasive species in each area ranged between 86 and 486, the majority being plants and fish.
Sanderson and colleagues assembled reports of predation by six nonindigenous fish species: catfish, black and white crappie, largemouth bass, smallmouth bass, walleye, and yellow perch. Hundreds of thousands to millions of juvenile salmonids were being consumed by these species at just a handful of sites, and for some of the species, salmonids constituted a large fraction of their diet. Yet despite the clear evidence of a substantial impact of invasive species on economically important salmonids, only a very small percentage of research funding is devoted to the potential harms to salmon resulting from invasives.
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Freshwater Fish Invasions
The Result Of Human Activity
Adapted from materials provided by PLoS Biology, via EurekAlert!, a service of AAAS.
Feb. 9, 2008 - Globally, invasive species represent a major threat to native species. A new paper* shows that, for rivers and lakes, where these invasions occur is predicted by human activity; find an area where economic activity is high and, in nearby lakes and rivers, up to a quarter of species will be migrants to the region.
In the first global analysis of invasions in aquatic habitats, Fabien Leprieur, Olivier Beauchard, and colleagues investigate what factors can predict invasion events and find that human activity is to blame.
Prior to this work, ecologists have debated the relative importance of human activity and intrinsic features of an ecosystem when trying to explain the distribution of invasive species. Researchers have suggested that the number of native species would predict the number of invasive species settling in an area.
This is because either an environment that is good for fish generally, and therefore hosts lots of natives, would be good for invaders too; or, conversely, because an environment that was host to many natives would be"full" to hopeful migrants.
Leprieur and colleagues from France, Belgium, and Canada investigated the fish species found in over 1000 river basins and found that the number of native species does not correlate with the number of invasive species.
Instead, they found that invasion was related to gross domestic product, with higher human population density, and with nearby urbanized land. This raises serious concerns for the future of many aquatic ecosystems as the rate of global economic expansion continues to rise, predicting an increase in invasive species and, with it, an increase in the extinction of native animals.
*Citation: Leprieur F, Beauchard O, Blanchet S, Oberdorff T, Brosse S (2008) Fish invasions in the world's river systems: When natural processes are blurred by human activities. PLoS Biol 6(2): e28. doi:10.1371/journal.pbio.0060028
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Global hot spots of freshwater fish invasion. (Credit: Image: Richard Robinson)
California Clearing Lake of
Northern Pike Fish With Poison
Adapted from materials provided by California Department Of Fish And Game
Sep. 29, 2007 - Northern pike (Esox lucius) are a nonnative invasive fish species that threaten California’s aquatic resources. California has been working to eradicate the fish from Lake Davis.
After a recent successful treatment of the creeks flowing into Lake Davis, the California Department of Fish and Game plans to begin a second stream treatment on Monday, Sept 24. The reservoir treatment is scheduled for Tues Sept 25 and Wed Sept 26. The reservoir is anticipated to be at 41,000 to 42,000 acre-feet at that time. The project uses a liquid rotenone formulation, CFT Legumine.
Releases from the dam into Big Grizzly Creek will be shut off for five days when the reservoir treatment begins. Current plans call for the dam to remain closed for up to 45 days to allow the rotenone formulation compounds to degrade naturally in the reservoir.
One day recently, DFG crews netted about 200 trout in Big Grizzly Creek immediately below the dam and moved them further down the creek where incoming springs will provide sufficient habitat after flow from the dam is shut off. About half the fish were 8 inches or larger in size, and about two thirds were brown trout, and the remainder rainbow.
After the first treatment in the creeks upstream of Lake Davis, several hundred dead pike were observed - mostly young-of-the year, one-year-old fish, and a few 2-year olds. In some areas, pike were the only fish found – demonstrating how pike can dominate an ecosystem. This summer, DFG field crews did intensive electrofishing in the creeks to reduce the numbers of pike and help keep them from spreading further up the streams. Nearly two thousand pike were removed by that control method.
Northern pike are top predators with long torpedo shaped bodies built for speed. Their camouflaged coloration enables them to hide in aquatic vegetation and ambush their prey. Once a pike is about 8 inches long, it primarily feeds on other fish which it grasps in its wide mouth. Pike are also highly fecund; for each pound body weight, a female can lay 10,000 eggs.
The dead fish pose no danger to wildlife, such as herons and coyote, which are scavenging in the area. The water is safe for wildlife to drink.
The stream treatments are carried out using 5-gallon drip stations in flowing water, while crews using backpack sprayers and trailer-mounted spray rigs treated standing water and backwater areas. Screens are placed at the mouths of the tributaries to prevent any pike from re-entering the creeks.
Post-treatment stocking will begin when Lake Davis is free of any of the rotenone formulation compounds, which is anticipated to occur before the reservoir freezes over.
The majority of the stocking will occur in Spring 2008, with several hundred thousand fingerling, sub-catchable, catchable, and bonus size rainbow trout, along with fingerling brown trout.
In addition to the information provided in the EIR/EIS for the project, an analysis of the seven lots of rotenone being used in the project has been conducted.
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Scuba divers researching conditions in Lake Davis. For the past several years, DFG has been controlling the pike population by electro-fishing. Pike have been found through out the Lake Davis watershed, from the dam up into the tributaries. So far, they have taken over 65,000 pike out of the reservoir. (Credit: Image courtesy of California Department Of Fish And Game)
Rotenone and Parkinsons
Medicinal Plant, St John's Wort, May Reduce Neuronal Degeneration Caused By Parkinson's Disease
Adapted from materials provided by Universidad Complutense de Madrid, via AlphaGalileo.
May 13, 2009 - A research team from the Universidad Complutense de Madrid (UCM) has carried out a study entitled, “Hypericum perforatum. Possible option against Parkinson's disease”, which suggests that this plant with antidepressant properties has antioxidant active ingredients that could help reduce the neuronal degeneration caused by the disease.
In the last few years, the idea that the excessive numbers of free radicals has an important role in the complex etiology of Parkinson's disease has spread. Post-mortem investigations have revealed evidence of lipid peroxidation as well as oxidative damage to the DNA of brain proteins in patients suffering from the disease. The increase of oxidative stress is attributed, among other factors, to a less active mitochondrial complex I. Certain environmental contaminants such as pesticides, and in particular Rotenone, can cause Parkinson's. Nevertheless, the mechanism that causes Rotenone to have these effects is not yet fully understood. The hypothesis is that the increase in the production of
Reactive oxygen species (ROS) caused by the altered function of the mitochondrial complex I could be the cause of the degeneration of dopaminergic neurons through the apoptotic process.
A proposition that is widely accepted is that ingesting high quantities of antioxidants can reduce the risk of suffering from Parkinson's disease or delay its progression. Natural products are highly appreciated in the development of drugs for their great structural diversity and wide range of pharmacological effects. Approximately one third of the best selling drugs in the world are, or derive from, natural substances. With this is mind, a plant well known for its antidepressant effects, St John's wort (Hypericum perforatum), was chosen for an in vivo test using a model of Parkinson's disease with rotenone.
St John's wort presents proven antioxidant effects, which make it beneficial for all those pathologies that cause an increase of free radicals. With the goal of determining which component of St John's wort is responsible for its beneficial role against neurodegenerative diseases, it was decided to evaluate the effects of a standard
Hypericum Perforatum extract with a 0.3% concentration of Hypericin, versus those of an extract with 11% Hyperforin but deficient in other active compounds of the plant. In the same experimental conditions as both these extracts, Quercetin was used as a positive control.
Body weight was controlled to determine whether or not the use of the different drugs had any significant impact on it. The pre-treatment of animals with both types of extract reduced the negative effects of Rotenone, as well as the loss of body weight during the chronic treatment. The obtained results after the catalepsy test show that the pre-treatment of animals with both extracts reduced the latency period increased by Rotenone. These behavioural alterations suggest that neurons in the nigrostriatal pathway are sensitive to the toxic effects of the pesticide. In fact, the administration of the toxin for a period of 30 days caused extensive lesions to that region, in many cases creating areas with missing neurons. The evaluation of neuron degeneration caused in the substantia nigra shows a reduction of dopaminergic neuron death with St John's wort.
The evaluation of antioxidant enzymes levels, superoxide dismutases, catalase, and glutathione peroxidase, conclude that administration both St John's wort extracts can prevent the increase of the three enzymes, reducing them significantly. St John's wort reduces the exacerbated production of Reactive oxygen species produced in the presence of Rotenone, as well as the damage that the free radicals cause dopaminergic neurons in the substantia nigra, avoiding the action of apoptosis. The neuron protecting effects are greater with the standard Hypericum Perforatum extract with the 0.3% concentration of Hypericin. This implies that the powerful antioxidant effects of the plant is caused by a synergic action of various of its active compounds.
The research team formed by Mª Ángeles Gómez del Rio, Irene Iglesias Peinado and Juana Benedí González, from the Departamento de Farmacología; Mª Isabel Sánchez Reus, from the Departamento de Bioquímica y Biología Molecular of the Facultad de Farmacia at the UCM has been awarded the CINFA 2008 prize (Real Academia Nacional de Farmacia) for their investigation.
