Despite surging anti-1080 sentiment, next year DOC is planning its biggest drop in history.
This weekend on Newshub Nation, we investigated the arguments for and against the controversial poison.
Is 1080 dangerous to our water supply?
A dangerous level of 1080 has never been measured in human or stock water supply. Since 1990 more than 3500 water samples have been taken following 1080 drops; of those, just 86 have come back with traces of 1080.
The official contamination limit is two parts per billion - the equivalent of two drops of ink in an Olympic swimming pool. Of those 86 positive tests, just six have been above two parts per billion, and four of those are believed to be false positives.
DOC says that at a level of two parts per billion, you would have to drink approximately 60,000 litres of water in a single sitting to have a 50 percent chance of dying. For reference, drinking more than six litres of water in a sitting could kill an adult through diluting the salt in their blood, leaving them unable to process electrolytes - a condition known as hyponatremia or water intoxication.
Is it dangerous to animals other than pests?
Dogs are particularly vulnerable to 1080. The poison can linger in carcasses for months after death, meaning dog owners are strongly advised to keep their pets on leashes in areas where 1080 has been dropped or not enter at all.
However, dog deaths due to 1080 remain rare. In the decade between 2007 and 2016 an estimated 27 dogs were killed, with a further five disputed deaths - either way that's around three a year. Meanwhile, the Greater Wellington Regional Council estimates 150 dogs have been killed by blue green algae over the past 15 years, around 10 per year. Then consider the unknown number killed by ordinary rat poison or being hit by cars.
Some kea have been killed from eating 1080, usually in areas where they have gotten used to being fed by humans. DOC has tracked a total of 71 kea through 1080 operations in Kahurangi National Park (2009-2016) at four different sites (Mt Arthur, Wangapeka, Anatoki, and Oparara), and two birds were poisoned.
However the overall effect of 1080 on kea populations has been positive. Kea nests were nine times more likely to survive and successfully produce chicks after aerial 1080 predator control.
No monitored kiwi has ever died from the use of 1080, despite what you may see on social media.
Photo of kiwi killed by dogs and cars passed off as 1080 poisoned birds
Is it an effective pest control?
After an eight-year operation in the 1990s, the number of kokako in the central North Island bounced back eightfold. In 2006, a 1080 drop in Tongariro Forest saw the survival of Kiwi chicks jump from 25 percent before the drop, to more than 50 percent in the following two years. In 2014, the nesting success of robin in the Marlborough Sounds jumped from 7 percent before, to 50% after the use of 1080.
At $33 a hectare aerial 1080 is currently the most cost-effective method for last scale pest eradication. The Bay Bush Action group says that the annual cost of maintaining fenced forest is around $3365 per hectare. Trapping setup costs alone are around $378 per hectare.
In 2011, a Parliamentary Commissioner for the Environment (PCE) investigation concluded "not only should the use of 1080 continue (including in aerial operations) to protect our forests, but we should use more of it".
Sources: Department of Conservation, Office of the Parliamentary Commissioner for the Environment, Bush Bay Action Group.
Originally published on Newshub Nation.