Overall, the presence of 1080 baits in the environment poses very little risk to people. This low risk is due to a combination of the properties of 1080 and the way it is managed. Very small amounts of 1080 are applied in pest control operations. Any residues remain in the environment for a short length of time. The series of controls on the use of 1080 virtually eliminate the chance of the public accidentally coming into contact with 1080 baits or residues.
Nevertheless 1080 is a poison, and there are many controls on its use to protect people during and after aerial 1080 operations. For instance:
• The Health Act specifically prohibits the contamination of any drinking water supply, and regional councils place restrictions over the application of 1080 around water bodies. Aerial operations must avoid water supplies – including restrictions on flights near water supplies by aircraft transporting 1080. Depending on the situation, intakes to drinking water supplies may need to be closed and monitored for the poison during aerial 1080 operations, and an alternative drinking water supply provided. Water cannot be taken from a water supply until monitoring has shown that 1080 is not present.155
• There are controls on how long after an aerial 1080 operation that people should not commercially harvest food from an area and this period must be clearly stated on signs and public notices. The withholding period for aerial 1080 is based on a minimum period of six months plus an additional period based on the length of time baits and poisoned possum carcasses take to break down at the site.156 The agency carrying out the operation must monitor
the breakdown of baits and carcasses in the operational area to determine if the withholding period needs to be modified. The warning signs cannot be removed until monitoring has shown no 1080 is still present.157
• Under the Hazardous Substances and New Organisms Act 1996 and the Health and Safety Act 1992 there are controls in place to protect those who prepare baits and carry out 1080 operations. Anyone handling 1080 must be properly trained and wear suitable protective clothing. 1080 must be packaged and transported in clearly labelled secure containers. Exposure limits for contact with 1080 have been set,158 and the health of all workers must be monitored
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6.4 Does 1080 kill humanely?
Determining the humaneness of different pest control techniques is not an absolute science. Humaneness is a relative measure that is based both on the time it takes a poisoned animal to lose consciousness and on the nature and severity of symptoms it experiences. Humaneness is also a somewhat subjective measure, and different people may have different opinions on how humane a particular pest control method is.
A recent report commissioned by the National Animal Welfare Advisory Committee (NAWAC) rated the relative humaneness of 1080 and other pest control techniques used in New Zealand.159 The results of the NAWAC report form the basis of
the humaneness assessments in this report. The NAWAC report rated 1080 as moderately humane.
1080 works by interrupting the body’s energy production systems: an animal’s cells are starved of energy and subsequently vital functions in the body stop. 1080 acts on different animals in different ways. Herbivores usually die of heart failure, whereas carnivores are more likely to suffer convulsions and respiratory failure.
The symptoms poisoned animals display also differ. Possums stop eating within an hour of consuming 1080, become lethargic and die between 5 and 40 hours later, depending on the dose consumed.160 Rats can show pain-related behaviours such
as increased grooming and stomach scratching, altered breathing, un-coordination and convulsions.
Deer have been recorded as becoming lethargic and lying down quietly without convulsions or leg-thrashing. However, researchers have noted that behavioural responses in deer to poisoning must be interpreted cautiously. This is because deer are known to frequently show no symptoms when in pain.161
Dogs, stoats, and ferrets have all been observed to go through states of fitting and uncoordinated movement to difficulty in breathing, lethargy, and paralysis. Vomiting can also occur.162 It is not clear how much carnivores suffer during
poisoning, as there is some evidence that they lose consciousness well before death occurs.163
The suffering of animals killed by 1080 can be reduced in two ways. First, baits can be designed to contain enough 1080 to ensure that they eat enough to die as quickly as possible. Second, painkillers may be added to baits.164 Currently baits
contain doses at levels that increase the likelihood of a fatal dose, but painkillers are not added to them.
There is no known antidote to 1080 poisoning, although veterinary treatment can reduce suffering in poisoned animals.165
National Animal Welfare Advisory Committee report rated 1080 as moderately humane
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6.5 Conclusions
1080 is a poison and like any poison has risks associated with its use. Many people are concerned about its safety and humaneness, although it is the most regulated pest control poison used in New Zealand. 1080:
• leaves residues for very short times in the environment, with one exception – it can linger in carcasses of poisoned animals under very cold and dry conditions for some months
• can still cause by-kill of both native and introduced animals, and although techniques are increasingly being used to reduce this risk, there is no way to protect uncontrolled dogs
• does not endanger people provided it is used as prescribed in regulations • kills different animals in different ways, but is not the most inhumane pest