Common pesticide linked to Parkinson's disease
13 November, 2000
The National Registration Authority for Agricultural and Veterinary Chemicals (NRA) is to conduct a detailed study into the pesticide rotenone following recent research findings linking the pesticide with Parkinson’s disease. The study will determine what implications the research by Emory University in Atlanta, Georgia, might have, if any, for chemical products containing rotenone registered for sale in Australia.
The NRA decision follows research to be published in the December issue of Nature Neuroscience, which showed that long-term exposure to rotenone induced many of the major symptoms of Parkinson’s disease in rats.
Researchers from Emory University found that intravenous administration of rotenone in rats produced effects that closely resembled human Parkinson’s disease, including slowing and abnormal movements, unstable posture, unsteady gait and some evidence of tremor.
The latest issue of New Scientist has quoted Abraham Lieberman, medical director of the US National Parkinson Foundation, as saying that it’s the first solid proof that long-term exposure to a toxin can cause this disease. However, he also added that the study needed to be repeated in primates.
Rotenone is a so-called natural pesticide extracted from the derris plant. It is widely used as an insecticide in gardens and to kill pests on pets. It is often formulated as dusts, powders and sprays for use in gardens and on food crops.
According to the NRA’s Chemical Review Program manager, Dr Ron Eichner, the study, to begin immediately, will involve an assessment of all available relevant scientific data.
In line with normal procedure in these cases, the NRA will work closely with the Federal Health authorities and the Therapeutic Goods Administration (TGA) for technical advice on public health issues in the conduct of the study.
The TGA however, has downplayed the research results saying that we should not be too concerned.
In the TGA’s preliminary examination of available information, including the overview of the US research, it noted that ‘in order to produce the brain lesions specific for Parkinson’s disease, the Emory University researchers had to infuse rotenone directly into the rat bloodstream for up to 5 weeks.
‘Studies conducted by the US National Toxicology Program in 1988, in which rats and mice received rotenone in their diets over a lifetime, appeared to show no evidence of any degenerative brain damage. This suggests that the route of exposure may be quite important in determining how much toxic material gets to critical sites in the brain.
‘The main products used as pesticides by organic farmers and home gardeners are based on Derris dust, which is the powdered extract of the Derris root. The rotenone content of Derris dust is generally less than 1 per cent so this may be a basis for an amelioration of concern about this type of product.’
‘The Emory University research involved the injection of high concentrations of rotenone directly into the bloodstream of laboratory animals. Whereas, when people use the chemical in the home garden it is done irregularly, in a very diluted form with potential contact being primarily on the skin,’ said Dr Eichner.
‘The NRA therefore considers that it is highly unlikely that the new study will identify any reasons for public concern in these latest research findings,’ he concluded.
However the NRA believes that the findings of a well-conducted scientific study from a respected institution cannot be ignored and deserve proper examination along with the other scientific data available on rotenone.
The special study will focus directly on the possible relationship between the results of the laboratory research involving rotenone administered to rats and any likely impact on human health of the use of the products in Australia.
For products containing rotenone, as with any other chemical product, the NRA strongly recommends that the user strictly follow the instructions set out on the label.
Rotenone appears to have been in use in Australia from about 1945. There is evidence of very early usage, as in 1649 it was reported as being used in South America to paralyse fish, which were then netted, and in 1848 in Asia, rotenone was apparently used as an insecticide to control leaf-eating caterpillars.
Last Reviewed: 13 November 2000
- 1. National Registration Authority for Agricultural and Veterinary Chemicals (NRA)
2. Nature Neuroscience 2000; 3 (12):1301-6
3. Nature Neuroscience 2000; 3 (12):1227-8
4. New Scientist daily news; ns9999129
