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ABSTRACT
Pyrethroids are a class of plant-derived insecticides and their man-made analogues that are increasingly applied in Canada as first choice for pest control in many agricultural and residential settings. Their popularity is partly due to their alleged safety compared to the older organochlorine and organophosphate insecticides. Application of pyrethroids is expanding because of recent increases in the level of pest infestations - such as bed bugs - and the decreased susceptibility of target species to many pest control products. Pyrethroid residues have been documented in homes, child care centres and food. While pyrethroids are considered of low health risk for humans, their increased use is of concern. Our current understanding of the adverse effects of pyrethroids derives mainly from studies of short-term effects in laboratory animals, case reports of self- and accidental poisonings, and high-dose occupational exposures, for which the levels and formulations of pyrethroid products differ from those relevant for long-term exposure in the general population. The available data suggest that the reproductive and nervous systems, endocrine signalling pathways, and early childhood development may be targets for adverse effects in the case of repeated exposure to pyrethroid formulations. Given uncertainty about the existence of long-term health effects of exposure to pyrethroids, particularly under realistic scenarios, we should be cautious when promoting pyrethroid products as safe methods for pest control.
Key words: Pyrethrins; environmental exposure; endocrine disrupting chemicals; toxicology; risk assessment
La traduction du résumé se trouve à la fin de l'article. Can J Public Health 2012;103(6):404-7.
Mots clés : pyréthrine; exposition environnementale; perturbateurs endocriniens; toxicologie; évaluation du risque
Pyrethroid insecticides and naturally occurring pyrethrins are commonly used for insect control in households and in agriculture. 1 Reasons for this are increasing restrictions in the use of organophosphate and organochlorine insecticides, the greater selectivity of pyrethroids for certain target species,2 their moderate acute oral toxicity in vertebrates and humans,3 and relatively low levels of environmental residues due to rapid degradation outdoors. 1 While pyrethroids have received both scientific2 and regulatory4,5 attention, questions remain as to their safety, especially for residential applications.
What are pyrethroids?
Natural pyrethrins are present in pyrethrum extracts obtained from flowers of some species of chrysanthemum. Because pyrethrins degrade easily under the influence of water and sunlight, more stable...