1080 Poison has continued to be a contentious topic in New Zealand. Recently, social media has come alight with protest and news surrounding the ‘dangers of 1080’, however, with the recent revelation that some of this news has been false, Craccum went to Associate Professor Malcolm Tingle, Associate Professor in Toxicology within the Department of Pharmacology and Clinical Pharmacology to find out the real truth about 1080.
What exactly is 1080?
1080 is the trade name for the highly water soluble chemical sodium fluoroacetate. This is a naturally occurring compound found in a number of plants in South America, South and West Africa and in particular Australia where there are over 40 plant species which produce it. Sodium fluoroacetate is synthesised for use in 1080 poison and is used in a number of countries such as the U.S.A and Australia.
How does 1080 work?
Sodium fluoroacetate is rapidly absorbed after eating and distributes to various organs of the body. The highest concentrations are in blood, with moderate levels in muscle and kidneys and low levels in the liver. Fluoroacetate combines with coenzyme A to form fluoroacetyl CoA, which is then converted to fluorocitrate by citrate synthase, Fluorocitrate then binds irreversibly to another enzyme, aconitase (1). Citrate syntase and aconitase are key mitochondrial enzymes involved in cellular energy production. Without sufficient energy production, organs with high metabolic rates are affected first, so the brain and heart are particularly vulnerable. There are other effects through disturbance of normal biochemistry that contributes to the toxicity of fluoroacetate. Possums will die through nervous system failure, cardiac arrest and respiratory failure within 6-18 hours of consumption of 1080. Not all animals are equally susceptible to 1080 however.
Why does New Zealand use this poison specifically?
Because it works. At a high enough dose, 1080 will kill any species, but generally carnivores are more sensitive than herbivores and birds and reptiles are even less sensitive. Invertebrates, like the weta appear not to be adversely affected by 1080. So, for use to protect native fauna, 1080 seems like a good pesticide because target species need to consume less poison per kg of body weight than the species trying to be protected.
In addition, if a sub-lethal dose is ingested, fluoroacetate is either excreted unchanged in the urine or undergoes metabolism by the liver and then the metabolites are excreted by the kidney, so there is little chance of the compound accumulating in the food chain, unlike some other pesticides. Fluoroacetate is very water soluble, so it will leach from uneaten bait and be dispersed into the environment. These factors make it suitable for aerial drops, where there is little control over the fate of the bait.
Are there risks to humans from 1080?
Well, everything is toxic, it is just a question of dose, so there must be some risk. In human beings, fluoroacetate is known to cause nausea, vomiting, and abdominal pain, followed by changes to the heart’s function and low blood pressure (hypotension), respiratory distress, anxiety, agitation, muscle spasm, stupor, seizure, and coma at higher doses. However, there are only a few case reports of actual human poisoning, often as a result of known suicide attempts and thus after ingesting very high doses. Secondary poisoning of humans from eating, for example, deer that have been poisoned with 1080, is considered unlikely because of its lack of accumulation.
Does 1080 impact our potable water supply? Can it poison us through the water?
Fluoroacetic acid was apparently investigated for its potential as a chemical weapon during WWII based on its mechanism of action and the fact that it is so water soluble, so could potentially be added to the enemy’s water supply. For environmental exposure, it is considered to be immediately dangerous to life only if the concentration in water is above 2.5 mg/m3, so it is highly unlikely ever to be of concern (and possibly why it was not pursued as a chemical weapon, since it would have required tonnes to pollute supplies). It is not considered genotoxic, so it is not predicted to cause cancer through chronic low dose exposure, nor is the any evidence that is causes birth defects.
Should we be concerned about the use of 1080?
It seems sensible to be cautious about any extensive use of chemicals. However, in this instance, the risks to humans are low. There are, of course, other considerations. In particular, some species, such as dogs are particularly sensitive to 1080 poisoning, so rigorous controls around non-target species getting into aerial drop zones could be an issue. There are animal welfare concerns with the use of 1080, in that animals may undergo a significant amount of distress before dying. In this regard, cyanide is perhaps the most humane, since death is so much faster, but it has poor species selectivity, considerable human toxicity and would not be suitable for pest eradication techniques such as aerial drops. In contrast, 1080 has a far smaller welfare impact than other pesticides, particularly the anticoagulants such as brodifacoum, and which are far more persistent in the environment.