Use of 1080 for pest control
Policy type: Position statement
Reference: 13b
Status: Current
Date ratified: 1 May 2015
Use of 1080 for pest control
The New Zealand Veterinary Association (NZVA) recognises that, in the absence of effective alternatives, the continued use of 1080 as a means of pest control (possums and some other introduced species) is necessary to assist the eradication of bovine tuberculosis and the conservation of New Zealand’s unique native flora and fauna.
Use of 1080 must be carefully managed to reduce the potential for accidental or secondary poisoning of non-target species especially dogs, which are extremely susceptible and food-producing animals that may enter the food chain (including wild animals hunted for food).
Background
The major user of the Vertebrate Toxic Agent* 1080 is OSPRI NZ Ltd [Operational Solutions for Primary Industries] under its Tbfree New Zealand programme (formerly the Animal Health Board), for the control of vectors of bovine tuberculosis (Tb), usually possums, followed by the Department of Conservation (DOC), for the protection of native plants and animals from a number of pests. Some regional councils also use 1080 for pest control and a small amount is used by other sectors, mainly forestry sector to protect new seedlings.
1080 is registered for use on the following target species in New Zealand: wallabies (carrot, cereal pellets and gel); possums (paste, gel blocks, carrots, apple and cereal pellets); rabbits (paste, oats, carrots and cereal pellets); deer (carrots and gel); rodents (cereal pellets); wasps (paste) and cats (fish meal pellet). Its use is tightly controlled and includes requirement for public notification in the areas in which it is laid.
New Zealand’s economy is heavily dependent on the export of products derived from animals. Trading partners demand product of increasingly high animal health standards, and their own livestock are mostly free from bovine tuberculosis. Therefore eradication of Tb from New Zealand domestic livestock is important for market access. Despite more than 30 years of a compulsory national Tb eradication campaign, the disease is still a significant problem because it is present in possums in large and often inaccessible parts of the country where there are no other cost effective control options available. Wildlife disease spreads to livestock in farms that border on to forest areas and seeds infection into possum populations in farm landscapes. Possum control is therefore central to Tb control.
Control of possums and introduced mammalian species (rats and mustelids in particular) is also essential to the preservation of much of New Zealand’s natural forest habitat and endangered bird, reptile and invertebrate populations. DOC uses 1080 also for wasp control in beech forests and for wallaby control.
The detrimental effects of possums on the environment are many and various: damage to native forests from browsing on leaves, flowers, fruit; predation on birds and their eggs; predation on invertebrates. Rats and mustelids are also predators of birds, reptiles and invertebrates. Browsing by wild goats and deer can interfere with forest regeneration. 1080.
Sodium monofluoroacetate, commonly known as 1080, is manufactured as a fine white powder. The active ingredient, fluoroacetate, is chemically identical to the fluoroacetate that occurs naturally in some poisonous plants found in Brazil, Africa and Australia. Plants with high concentrations can be toxic if eaten, but do not occur in New Zealand.
1080 is used in the form of a paste, cereal pellets, carrot baits, gels and fish-based pellets, depending on the species targeted and the terrain. It is applied by aerial spreading, or by ground operations that use bait stations; as a paste spread on upturned earth spits, small bait stations or retrievable cardboard squares or tin lids; or spread by hand in small areas.
The toxic effects of 1080 result from disruption of the Krebs cycle. Possums usually die in 6-18 hours from heart failure. Herbivores also suffer heart failure. In carnivores 1080 causes central nervous system disturbance resulting in convulsions and death from respiratory failure. Sub-lethal doses are metabolised and excreted without accumulation in the body, with the dose likely to be eliminated within a week. However, long-term damage can occur, e.g. myocardial necrosis in sheep (Eason & Wickstrom).
Under favourable conditions, 1080 undergoes defluorination within 1 -2 weeks, but in extremes of cold or drought, this process can be delayed. Rainfall assists with detoxification and particularly for pelleted forms the toxin will be mostly deactivated after significant rainfall. Aerial operations actually require clear time periods for application to avoid this. Public notification is required for areas where 1080 has been laid and particular effort is made to notify users of forested areas with dogs, though once rain fall has been significant the primary danger is secondary poisoning through animals consuming the carcases [especially in cold conditions with delayed carcase breakdown]. Most operations today set up carcases and monitor breakdown rates before finalising removal of 1080 Danger notification signage.
Advantages and disadvantages
1080 has been the vertebrate toxic agent of choice for possum control. It has the advantages of being the only one registered for aerial application , which allows control operations in areas otherwise inaccessible or difficult to access, and of being relatively cheap. It is highly effective for killing possums and rats, giving rapid reduction in numbers of these pests. It is rapidly biodegradable, quickly diluted in waterways, and is broken down in both soil and water by microorganisms so does not build up in the environment, except under the unfavourable conditions mentioned previously.
Its disadvantages lie in the risks it poses to non-target species. It can have direct effects, especially in dogs, which are extremely sensitive, or through the ingestion of poisoned carcasses. Historically there have been 1080 pest control operation failures which resulted in non-target native animal deaths.
There is currently no antidote for poisoning with 1080, and treatment is difficult and depends on early presentation (McLaren 1999, Parton et al 2001, Williams 2009). Recent reviews/reports
The 2007 Environmental Risk Management Authority (ERMA) reassessment of 1080 determined that the continued use of 1080 had significant advantages outweighing the dangers provided used compliantly, however additional controls on aerial application were introduced particularly focused on accidental delivery of toxin outside of operational boundaries as this had been shown to be a high risk event for non-target deaths. The review also included increased monitoring of operations, strengthening existing controls, promoting best practice and conducting further research into alternatives for pest control and the effects of 1080. It also identified requirements for evaluation of and exclusion of use in some water catchment areas used for potable water sources [no fly zones for aerials].
In 2011 industry guidelines were developed by the National Pest Control Agencies to assist with compliance with HSNO and ACVM requirements for use of registered 1080 products and there are strict conditions around communication, signage, handling, storage, records, reporting, bait preparation, transportation, permission to use (from DOC and/or the local Public Health Unit), application, tracking of delivery [flight lines], emergency management, decontamination and disposal.
In 2011 the Parliamentary Commissioner for the Environment investigated the use of 1080 and strongly endorsed the ongoing use of aerial 1080 pest control operations to protect native forests and the animals in them due to the lack of viable alternatives. She made additional recommendations around simplifying regulations, communication and improved access to information.
In 2013 the EPA released a review of aerial 1080 operations over the previous 5 years which found that these management controls are working well and there was no evidence of adverse impacts on water quality.
Public concerns
Some New Zealanders have expressed their opposition to the widespread use of 1080. Concerns expressed include questions on the humaneness of the toxin, the risks to non-target species, possible appearance of 1080 in the food chain, and contamination of environment and waterways from aerial application over wide areas. Evidence suggests that much of the publicly voiced concern is unfounded and that risks can be managed by selection of application method.
Public opposition to 1080 based on perception of toxins as inhumane remains unchanged, and is balanced against the economic and environmental losses which would be sustained if 1080 were not available for vertebrate pest control and the lack of a viable alternative.
Improvements in methodology for aerial distribution include improved consultations and notification procedures, the increased accuracy of distribution using global positioning systems, improving bait spreading machinery, changes to toxin loading of the baits, improved bait quality, size and bait characteristics. These have led to a reduction in aerial application rates by over a factor of 3, over the past 25 years for both cereal and carrot baits and markedly reduced risks to non-target animals. Non-target species of interest to Hunters form a particular concern expressed in public forums and deer repellent "coatings" have been developed and shown to be particularly effective for reducing deer kill, though in crown land non-RHA areas this is at the discretion of DOC determination.
Buffer zones and caution periods are used to manage the risks to food safety. A buffer zone of 2 km is imposed around treated zones to prevent removal of wild animals for food from around poisoned areas. Caution periods (defined by time and rainfall) are imposed to restrict the removal of wild animals for food during risk periods.
Ground operations are used in areas where it is necessary to avoid exposing livestock, pets, people or native animals.
In response to concerns from anglers regarding trout eating 1080 poisoned mice, research which commissioned by DOC was evaluated by Ministry for Primary Industries which concluded that the peak levels of 1080 temporarily reached within force-fed trout in the laboratory fell well short of breaching internationally accepted standards for human health, and that the levels were likely to be a ‘gross overestimate’ of any likely residue to be found in wild trout.
All 1080 operations are strictly controlled by health and environmental regulations to ensure its safe use. The management regime set by the Environmental Protection Authority (EPA) and regional health authorities requires detailed operational conditions and regular reporting including water quality monitoring. Many areas also utilise bird count data and registers of other non-target species deaths.
Scientists conclude that on present evidence, the ecological costs of using vertebrate toxic agents such as 1080 is much less than the damage resulting if they are not used.
Poisoning of non-target species
Non-target species can be poisoned by direct ingestion of 1080 or by secondary poisoning through eating carcasses of poisoned possums or other animals.
Species vary in their sensitivity. In general, dogs are particularly sensitive, herbivores and birds are less sensitive, and reptiles and amphibians less sensitive again. Body size is important, and although the LD50 for birds is relatively high, very small insectivorous birds are particularly at risk. Fish and aquatic species have low sensitivity.
Predatory and scavenging birds such as harriers and Moreporks are at risk of secondary poisoning from eating dead possums, rodents, small birds or invertebrates.
Secondary poisoning is common in dogs because of their scavenging habits, and particularly when the dog consumes the whole carcase including the gastrointestinal tract. Dogs should be muzzled in areas where 1080 has been laid. Secondary poisoning can also occur in cats.
Effective control of dogs by dog owners will reduce the opportunity for dogs to be poisoned with 1080.
In cases of suspected 1080 poisoning, samples for diagnosis include vomitus, rumen or stomach contents, fresh liver and muscle.
Research from DOC shows that non-target native species can still be killed in 1080 operations (in particular kea, weka, robins and tomtits) however measures are taken to minimise the impact by careful control of bait quality, use of dark green dye and cinnamon lures to attract possums but repel most birds, and avoiding operations in open areas. Post-operation monitoring has shown that the benefits of protecting breeding birds and their nests from predators strongly outweigh the low rate of mortality recorded for these species e.g. kea nests on the West Coast protected from predators by 1080 produce four times as many chicks as the unprotected areas which offsets the 12% mortality recorded in kea tracked through 1080 operations.
Alternative control methods
Currently the other options for control of pest animals are trapping, hunting and the use of other vertebrate toxic agents. The NZVA recognises that, despite concerns about its humaneness (Sherley 2007), 1080 has numerous advantages over the other toxic agents and methods available at present, but looks forward to research into pest-specific toxins and other means of control (including fertility control) yielding alternatives in the future.
References
Champeau O, Knight B, Tremblay L. 1080 Uptake and Elimination in Rainbow Trout, Cawthron Institute Report No. 2611 October 2014
Eason CT, Wickstrom M. Vertebrate pesticide toxicology manual (poisons): Information on poisons used in New Zealand as vertebrate pesticides. Department of Conservation Technical Series 23. http://www.doc.govt.nz/upload/documents/science-and-technical/docts23a.pdf (accessed 16/03/09)
McLaren J. Treatment of 1080 poisoning in dogs. Vetscript, March 1999
Parton K, Bruere AN, Chambers JP. Fluoroacetate – 1080 in Veterinary Clinical Toxicology, Veterinary Continuing Education 208, 141-53, Massey University, 2001
Sherley M. Is sodium fluoroacetate (1080) a humane poison? Animal Welfare 16, 449-458, 2007
Williams V. You can save dogs poisoned with 1080. Vetscript, February 2009
Wright, J. Evaluating the use of 1080: Predators, poisons and silent forests, Parliamentary Commissioner for the Environment Report, June 2011 www.pce.parliament.nz
Controls for formulate substances containing sodium fluroacetate (1080). www.ermanz.govt.nz/news-events/1080/controls%20document.pdf
Reassessment of 1080, Environmental Risk Management Authority, August 2007
B9 Aerial 1080 Pest Control Industry Guidelines, National Pest Control Agencies, April 2011
