1080 Poison

Compound 1080 or sodium monofluoroacetate, is a naturally occurring compound produced by many species of Australian plant. Sodium monofluoroacetate occurs naturally in about 40 native plant species in Australia, primarily of the genera, Gastralobium, which grow in Western Australia, across northern Australia in the Northern Territory and in central Queensland. No fluoroacetate bearing plants are known to occur in Tasmania or the other southern States.

Compound 1080 is a white fluffy powder that is odourless and tasteless. 1080 was first synthesised in Europe in 1896 and developed in the USA as a rodenticide during the 1940s. It was first used as a rabbit poison in Tasmania in 1952. It is now widely used in Australia and New Zealand to control pest animals.

How it is used

The Department of Primary Industries and Water is the only importer of 1080 into Tasmania and only authorised officers of the Department handle the poison. The powder is dissolved in water to make a 1.5 per cent solution. This is coloured blue to give it a distinctive appearance to avoid accidental misuse and to reduce its acceptability to birds.

In the field, it is mixed with bait material, usually chopped carrot, to provide a final concentration of 0.014 per cent of the active ingredient.

Wild animals such as wallabies and possums may only be poisoned where officially permitted by the Wildlife Management officers of the Department of Primary Industries and Water. Such permits will only be issued if poisoning is an essential element of their wildlife management program.

Species Susceptibility

The relative toxicity of 1080 to various animals is shown in table 1. Dogs and cats are highly susceptible. Next are all herbivores. Rats, wombats and humans are less susceptible, while quolls, Tasmanian devils and nearly all birds have a high tolerance to 1080 poison.

Table 1: Relative susceptibility of various animals to 1080 poison

AnimalLethal dose mg 1080/kg
body weight
Relative tolerance
dog = 1
Dog0.061
Cat0.46
Bennett's Wallaby
Pademelon
<0.2
0.13
3
2
Rabbit0.47
Cattle, sheep, deer0.2-0.63-10
Possum0.712
Rat1.017
Wombat1.525
Man2.040
Eastern quoll3.760
Tasmanian devil4.270
Mouse13220
Birds3-1950-300

Secondary poisoning

As can be seen from Table 1, dogs and cats are very susceptible to 1080 poisoning so every precaution should be taken to prevent dogs from eating poisoned carcases.

If a dog or cat ate a pademelon poisoned with 1080, it could obtain a lethal dose of the poison. In fact, one dead pademelon could contain enough 1080 to poison 12 dogs or 9 cats. Other carnivorous animals and birds are not likely to be killed by secondary poisoning as they would need to eat their own weight in poisoned rabbits to obtain a lethal dose (see Table 2).

Table 2: Amounts of poisoned Pademelon likely to be fatal to various carnivores

Carnivore and weightNumber of Pademelons
Dog (10 kg)1/12 or 510 gms
Cat (2 kg)1/9 or 660 gms
Man (70 kg)6 - 20
Eastern quoll (1.2 kg)2/3 or 3900 gms
Tasmanian devil (5 kg)3
Eagle (4 kg)5

These figures are approximate and assume that:
1. the pademelon weighed 6 kg and ate 50 g of carrot bait, and
2. 1080 is evenly distributed through the carcase.

Actually the poison is present in larger concentrations in the stomach and some other organs such as liver, heart, lung, kidneys and brain. Carnivores which show a liking for these organs therefore have an increased susceptibility to secondary poisoning.

Symptoms

There is some debate about the humaneness of 1080. However, this is less so in respect of its effect on herbivores, including target species such as rabbits and wallabies. Herbivores typically show no obvious signs of poisoning until their sudden collapse. Some herbivorous animals experience convulsions, others simply lie still, breathing slowly, until death occurs. Death in herbivores is typically the result of ventricular fibrillation (heart irregularities). Symptoms of nervous distress are seen in dogs, cats, and man, but from reports from men who have recovered, no pain is felt. Rabbits and wallabies usually die several hours after eating the bait and so die some distance from the burrow. The number of dead animals found near the burrow therefore cannot be used to assess the efficiency of the poisoning program.

Effect on the Environment

In use, 1080 does not accumulate in the environment. It is applied locally at relatively small rates and is readily degraded in soils, surface waters and by micro-organisms.

The usual fate of 1080 in baits is to be consumed by the target pests in the days or weeks following baiting.

Most of the 1080 ingested by animals is rapidly metabolised and/or excreted, with only low levels retained in the carcass.

Poisoning of non-target animals may occur with 1080 baiting. However, the impacts are either localised, or limited to individual animals and do not result in significant adverse effects on the non-target animals at a population level.

Careful attention to the selection of bait material, amount of 1080 in each bait, timing and placement of baits combined with preliminary free feeding to reduce bait shyness, increases the acceptance of poisoned baits by target animals.

Comparison with other Poisons

Strychnine is the main legal alternative poison used in vertebrate pest control in Australia, although its use is restricted in Tasmania.

It is inferior to 1080 because:

  • It is less humane, causing a violent death with convulsions and pain. The onset of symptoms is quick but death may not occur for 2 hours or more.
  • It is less specific; all species of animals and birds are susceptible.
  • It produces a violent death near the burrow, disturbing other rabbits so that fewer rabbits are killed.
  • It has a bitter taste, is not water soluble and is more difficult to use.
  • It is more dangerous. A child would be readily killed by one piece of apple poisoned with strychnine, but would need to eat at least 15 pieces of carrot poisoned with 1080.
  • It is not broken down on the bait or in the soil.
Other poisons, such as organophosphates, may not be used legally for vertebrate pest control. These poisons are totally non-selective and their use could threaten the survival of some species, particularly predator birds such as hawks and eagles.

Pindone is used for rabbit control in areas where there is an increased risk of secondary poisoning of dogs. It is an anticoagulant, and there is an antidote available, but native carnivores and birds of prey may be at greater risk from eating poisoned carcasses.

Summary

Compound 1080 is the most effective vertebrate pest poison currently available. It is relatively species-specific, it is relatively humane in terms of its effects on herbivores and it is biodegradable.

There is a definite risk of accidental poisoning of sheep, cattle, goats, horses and pigs, so every care must be taken to keep stock away from a poisoned area until all uneaten poisoned bait is removed.

There is a high risk of secondary poisoning if dogs eat poisoned rabbits or wallabies.

Poisoned animals are not found near the burrow so a count of carcases cannot be used to assess the effectiveness of the control operation.

All 1080 poison operations in Tasmania are performed under the supervision of DPIPWE Wildlife Management officers. These officers ensure that the operation is carried out according to the Code of Practice for Use of 1080 Poison for Native Browsing Animal Control.

Further reading

Wikipedia - Sodium Fluoroacetate

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