The chemistry of 1080

1080 is the brand name for sodium fluoroacetate – a manufactured poison. It is the sodium salt of a naturally occurring plant toxin called fluoroacetate. Plants use this toxin to defend themselves from herbivores. There are around 40 different plant species that produce fluoroacetate. Examples include Southern Africa’s gifblaar (poison leaf) and Western Africa’s ratsbane (a natural rat poison). In Australia, it is found in members of the wattle family and plants known as poison peas.

Sodium fluoroacetate was first synthesised in 1896 by treating sodium chloroacetate with potassium fluoride. It was patented in Germany in 1927 for use as a pesticide. In 1944, the US Fish and Wildlife Service researched a number of rodenticides (poisons that kill rodents), and rather than write the long chemical name for sodium fluoroacetate, they used the laboratory catalogue number – 1080.

How 1080 works

The chemical formula for sodium fluoroacetate (1080) is CH₂FCOONa. Once within the body, it goes through several chemical changes.

The sodium ion (Na⁺) dissociates (separates) from the fluoroacetate. Fluoroacetate is then converted to its acid form – fluorocitrate – which affects the function of several enzymes in the cell mitochondria. Because of this, the body’s cells cannot convert food into energy (the process of cellular respiration). As a result, the body’s organs begin to fail. Herbivores usually die of heart failure. Carnivores usually die of respiratory failure.

Small animals usually begin to show symptoms within half an hour. With larger mammals, it takes about 3 hours. Possums become lethargic and usually die within 5–40 hours. Carnivores – like dogs, ferrets and stoats – may experience convulsions, spasms, vomiting and paralysis. There is no antidote to 1080, but inducing vomiting in dogs as quickly as possible may save their lives.

Does 1080 cause suffering?

The simple answer is yes. Most forms of pest control that use poison (whether in bait stations or from aerial operations) cause some suffering. The National Animal Welfare Advisory Committee rates poisons from most humane (grade 1) to least humane (grade 8). 1080 is grade 6 – severe. Most commonly used poisons are also grades 6–8.

On the other hand, some people argue that introduced pests inflict suffering when they predate native birds and other creatures. Others say that, even though 1080 causes suffering, it’s still necessary if we are to protect our native ecosystems as well as control the spread of bovine TB.

Toxicity, dose and tolerance

For pest control purposes in New Zealand, the recommended amount is 1.5 grams of 1080 per kilogram of bait (1.5 g/kg). Aerial operations use less than 2 kilograms of bait per hectare. Rats and possums eat the 1080 bait. Stoats and ferrets are killed by secondary poisoning – from eating rats or possums that have recently eaten 1080. Dogs and other non-target species can also be affected by secondary poisoning.

LD₅₀ is a general indicator of a substance’s toxicity within a short space of time. Dogs are particularly susceptible to 1080, and their LD₅₀ is a mere 0.07 mg of 1080 per kilogram of body weight (Eason et al., 2013). The LD₅₀ for rats and possums is 1.2 mg/kg (Eason et al., 2013) and 1.4 mg/kg for a ferret (Hansford, 2016).

Reptiles and amphibians have slower metabolism and are less sensitive to fluorocitrate. They are more likely to neutralise and excrete the toxin. Fish also have very low sensitivity to 1080. The lethal concentration for rainbow trout is 54 mg/litre of water or three fully dissolved baits per litre of water (Hansford, 2016).

1080 has the potential to kill invertebrates – it has been used as an insecticide for the control of fleas, wasps and aphids. However, invertebrates are not likely to encounter 1080 baits used in New Zealand as they do not seek them for food.

References

Eason, C.T., Ross, J. & Miller, A. (2013). Secondary poisoning risks from 1080-poisoned carcasses and risk of trophic transfer – a review. New Zealand Journal of Zoology, 40(3), 217–225. DOI: 10.1080/03014223.2012.740488

Hansford, D. (2016). Protecting Paradise. Nelson, New Zealand: Potton & Burton.