A review of recent regulatory and environmental toxicology studies on 1080: Results and implications

Sodium monofluoroacetate (1080) is a highly toxic vertebrate pesticide that has been widely used for possum and rabbit control in New Zealand since the 1950s. Because of its importance in pest control and the highly toxic nature of this compound, its environmental fate, persistence, non-target impacts and general toxicology have been and continue to be extensively studied. A series of in vitro (cell culture) and laboratory animal studies (in rats and mice) have recently been undertaken to update the regulatory toxicology database for 1080. Results of three different, complementary tests indicate that 1080 is not mutagenic, and therefore unlikely to cause cancer. Results of developmental toxicity studies indicate that 1080 causes developmental defects in rats when pregnant females are exposed to relatively high doses (0.33 and 0.75 mg kg(-1) day(-1)) on a daily basis during the period of organogenesis (from days 6 through to 17 of gestation). The developmental abnormalities observed were mild skeletal effects: slightly curved forelimbs, and bent or "wavy" ribs. These results highlight the highly toxic nature of 1080 and the need for extreme care when handling this pesticide during the manufacture and distribution of bait, but do not preclude its proper use. The morphological changes in foetuses observed in the recently completed rat developmental toxicity studies are likely to raise concern regarding the exposure of humans (particularly pregnant mothers) to 1080 through contamination of waterways after the aerial sowing of 1080 baits. However, ongoing monitoring (1990-98) of waterways from areas where 1080 baits have been aerially sown confirms that there is negligible risk of human contact with 1080 through this route of exposure.