Here is the Department of Conservation reply, received directly: 5 June 2020
Dear Waikato Conservation Board Chair and Members
Thank you for your information request to the Department of Conservation. We hope this information will assist you in answering the question that was raised at your previous meeting and provide supporting information that addresses the concerns
that were voiced by the attendees. In saying that we note that the broader information discussed below only touches on
the actual information available on these issues. There is a wide array of information about the use of 1080 in predator control available on the Department’ s website.
The following response references a number of the more salient links in respect of the issues that have been raised.
Question posed by the attendees

As we explain below, our understanding is that concerns about the nature of the tests that are conducted in relation to 1080 arise from a fundamental misunderstanding of the scientific basis for testing for Fluoroacetate as opposed to Fluorocitrate.

The department holds a contract with Manaaki Whenua Landcare Research to conduct toxicology tests including testing in relation to 1080. Manaaki Whenua is accredited to test for 1080 and has a biodiversity focus and is presently the only
accredited laboratory in New Zealand that can provide the full array of testing the Department requires
Useful information about their accreditations and work can be found here:
https://www.landcareresearch.co.nz/resou...
As an accredited laboratory they are the experts in what is and what is not the most appropriate means of testing.

Fluoroacetate and Fluorocitrate
Manaaki Whenua - Landcare Research has provided DOC with an explanation of why it does not test for fluorocitrate when testing for the suspected involvement of 1080 in relation to the death of an animal.
1080 is made up of sodium and a compound called fluoroacetate (which is why it is often referred to as sodium monofluoroacetate). When ingested, the sodium and
fluoroacetate break apart, with the sodium becoming harmless. The sodium has the same composition at that point as the sodium in table salt. The fluoroacetate component of 1080 is metabolised (broken down and transformed) by animal cells
into a range of non-toxic substances, plus the toxic chemical fluorocitrate.
The toxic effects of 1080 are a result of this transformation of fluoroacetate into fluorocitrate, which has the effect of interrupting the way that cells generate energy, in a biochemical process called the krebs cycle. When cells cannot generate energy, they die, which occurs on a wide scale with the ingestion and breakdown of 1080. This leads to the death of the animal.
There are two main reasons why testing for fluoroacetate is appropriate:
Firstly, animals poisoned with a lethal dose of 1080 will always die with detectable fluoroacetate in their system, because there will have been enough fluorocitrate to kill the animal before all the fluoroacetate can be metabolised and/or excreted. Only small amounts of fluoroacetate are converted to fluorocitrate. Lab research by Savarie (1984) states that the amount converted may be 3% of the total, leaving the other 97% as fluoroacetate. Other studies suggest the proportion is around 1- 2.5%.
Secondly, fluorocitrate is more difficult to test for because it remains strongly bound to the aconitase enzyme within the cell’s mitochondria (where it causes the block in the Krebs cycle that kills the organism). As the fluorocitrate is connected to the
enzyme, normal lab tests to find it are significantly less effective.
There is, therefore, a much higher chance of detecting sodium fluoroacetate than fluorocitrate in a poisoned carcass. Manaaki Whenua - Landcare Research’s tests for
1080 are sensitive to 0.001ug/g – one part in a billion. It is in the departments best interest to know when 1080 has contributed to the death of an animal in question. DOC, therefore, considers that if an animal had been killed by 1080 then Manaaki
Whenua - Landcare Research would be able to detect 1080 in the carcass by the presence of fluoroacetate alone.
Scientific theory can only be displaced with evidence
There is one further point that we think is worth noting in response to the issues that have been raised. Our understanding of science shifts where there is new evidence to
support either a change or departure from an existing theory where it has been discredited by any such new evidence. The mere fact a scientific theory or body scientific evidence has existed for a long time does not invalidate it simply by virtue of
its age. There are numerous examples of famous scientific theories that still stand despite being hundreds of years old. As we have noted, we rely on an accredited
'Toxic characteristics of fluorocitrate, the toxic metabolite of compound 1080', Savarie, 1984

laboratory to undertake the testing we require in relation to 1080. The experts there are best placed to determine the type of test that is actually required.
Other concerns
The attendees have raised a number of concerns in relation to the Department’s use of 1080 in its predator control programmes. We touch on these briefly below and
again note that a wide array of information is available on our website and is otherwise publicly available.
Public Health
The Department works with the Ministry of Health, the Environmental Protection Authority and Worksafe New Zealand to manage risks to workers and the public during pest control operations. The separate roles and responsibilities of these
agencies are explained here:
https://worksafe.govt.nz/about-us/news-a...
Before an operation can take place, permission must be received from the relevant Public Health Unit. This permission covers the measures that must be taken to protect the health of all members of the public.
This approval includes conditions on excluding waterways that supply drinking water. Drinking water supplies are always safeguarded by buffer zones set by health officers to ensure there is no temporary contamination by 1080.
The Ministry of Health document Guidelines for Drinking-water Quality
Management for New Zealand contains information on health considerations for 1080, including a derived potential exposure value for inhalation of 1080.
The WorkSafe document Workplace exposure standards and biological exposure indices may also be of interest to you.
These documents are respectively available at:
https://www.health.govt.nz/publication/g...
management-new-zealand
https://worksafe.govt.nz/topic-and-indus...
health/monitoring/exposure-standards-and-biological-exposure-indices/
Operation Rationale
Each aerial 1080 operation run by the Department undergoes an internal permission process, which includes identifying targets and the rationale behind an operation, as well as the legal permissions required to enable work to occur. Examples can be found here:
https://www.doc.govt.nz/news/oia-respons...

Monitoring
An important point to understand in relation to the monitoring we undertake is that while the Department monitors pest numbers for various purposes including effectiveness of aerial 1080 operations, the most meaningful measure of pest control
outcomes is the response shown by vulnerable native species. Ultimately, success is measured by the increase in native species populations and the reality is that threatened native birds and wildlife are thriving due to our Tiakina Ngā Manu
predator control programme.
The Department’s website hosts a large amount of publicly available information on monitoring.
We recommend this publicly available article that describes our management approach: Elliott, G. and Kemp, J. (2016), Large‐scale pest control in New Zealand beech forests. Ecol Manag Restor, 17: 200-209. doi:10.1111/emr.12227
For further explanation please also see:
www.doc.govt.nz/our-work/biodiversity-in...
www.doc.govt.nz/globalassets/documents/s...
monitoring/guideline-to-monitoring-populations.pdf
Biodegredation of 1080
Tests in a range of New Zealand soils and leaf litter show microbes break down the remaining traces of diluted 1080.
Bacteria and fungi in soil make natural catalysts (enzymes) that detoxify 1080. These release compounds which the microbes use as a food source. Whether tested in the lab or in the bush, studies show soil bacteria can thrive when 1080 is present.
Once 1080 biodegrades, all that remains in the soil are natural compounds and minerals. These include glycolate, fluoride and carbon, at levels that are normally found in the environment.
The time 1080 takes to biodegrade in soil depends on the weather.
At temperatures around 10–20 °C, 1080 washed from the bait pellets is broken down by soil organisms within 1-2 weeks. This still occurs at temperatures as low as 5 °C, but more slowly. In cold, dry conditions, traces of 1080 might take a few months to
completely biodegrade.
The Department does not carry out research into the ‘biodegradation’ of 1080, as that topic is outside our area of speciality. However, there is research from other
organisations available online. You may like to start your search with : 'An updated review of the toxicology and ecotoxicology of sodium fluoroacetate (1080) in relation to its use as a pest control tool in New Zealand, Eason et al. 2011, which is
available on the New Zealand Journal of Ecology website at:
https://newzealandecology.org
This paper discusses the breakdown of 1080 and cites numerous other papers on the subject.

1080 entering a waterway
Any bait pellets containing 1080 that fall into a stream, river or lake are rapidly diluted to harmless levels and almost always undetectable in a waterway after 24 hours. When a bait pellet containing 1080 falls into water, two things happen:
• the 1080 dissolves and is washed out of the pellet, even before the pellet
breaks apart. This process happens quickly, especially in flowing water
• the 1080 washed out of the bait becomes so diluted it cannot work as a toxin.
In laboratory experiments that simulated water flowing over pellets in a stream, about half of the 1080 had been washed out after 5 hours and more than 90% after 24 hours. No 1080 was detected in the water after 36 hours.
Only a very small fraction of a pellet (0.15%) is the chemical 1080 – the rest is cereal, binding agents and flavouring that make it attractive to predators. When wet, baits lose their green colour after 2 days, start to swell and break apart after 3 days, and disintegrate after 4 days.

Keeping 1080 out of drinking water
We use sophisticated GPS technology to keep 1080 pellets out of exclusion zones.
Toxic pellet baits containing 1080 are only effective on land, so we avoid wasting them by sowing them over water. However, sometimes baits will be sown over waterways that are not part of exclusion zones, in order to make sure there are no
gaps in the treatment area.
To ensure our drinking water is always safe, the Ministry of Health has set a stringent guideline that 1080 can only be present at levels below 2 parts per billion (ppb). This
is the equivalent of about 3 pin heads on a football field.
At these extremely low levels, an adult weighing 70 kg would have to drink 70,000 litres (or 230 baths full) in one go to receive a fatal dose. No tests of drinking water after 1080 operations have ever come close to this limit.
For the 1299 samples of water used for human or stock drinking supplies tested between 1990 and 2016, only 5 contained traces of 1080. These had 1080 residues ranging from 0.1 to 0.2 ppb. No 1080 was found in the other samples.

Drinking stream water
It is extremely unlikely that stream water will be contaminated by 1080. Bait pellets that land in a stream have their 1080 washed out and diluted very quickly. When it rains after a 1080 operation, rainwater washes most of the 1080 from uneaten baits into the soil, where it is biodegraded by microbes.

1080, the environment and plants
A NIWA field study in 2012 investigated whether 1080 could dissolve out of baits and end up in streams after heavy rainfall. The study was unable to detect any traces of 1080 in groundwater or stream water, despite using 25,000 times more 1080 than usually applied in an aerial operation.
The only samples that tested positive for 1080 (7 of the 59 samples) came from soil water. These samples contained much lower levels of 1080 than the Ministry of Health standard for drinking water.

We hope this will help in your discussions at your next meeting and appreciate the
opportunity to assist.

Yours sincerely,

The Departme