Week in Review

Questions raised over Westport rat 1080 results

Results released over the weekend of independent testing of some of the carcasses found in Westport have done little to solve the mystery of what killed over 600 rats

Test results from an unnamed mysterious laboratory on rats and other wildlife that washed up on a Westport beach have puzzled toxicologists, with one describing the results as "very unusual" and in direct conflict with published studies.

The secret laboratory’s results show levels of 1080 and related substances present in rats, birds and a starfish. This differs from results reported by the Department of Conservation (DoC) which found no trace of 1080 present in rats.

Numerous theories have been put forward as the reason more than 680 rats washed up in Westport. These include 1080 poisoning, a flash flood, mass suicide, poor swimming ability or a farmer using rat bait. Bad weather and a spike in rat numbers caused by a mast year have been suggested as a possible factor in the unusual incident. Rat tracking from tunnels in the area of forest which 1080 was dropped on had reached 87 percent, in non-mast years rat tracks are only found in around 10 percent of tunnels.

DoC came under criticism for only testing for fluoroacetate, and not for fluorocitrate. The 1080 poison - fluoroacetate - causes a reaction in the body that creates fluorocitrate.

The test results released by Flora & Fauna of Aotearoa and Clean Green New Zealand Trust from an unnamed laboratory found fluoroacetate (1080) in rats and shearwater and fluorocitrate in rats, weka, shearwaters and a starfish.

The lab also reported finding traces of the green dye used in 1080 baits in rats and shearwater.

The published results were handwritten on forms which appear to have been downloaded from a US laboratory. This, and other aspects of the tests, have raised questions about the laboratory which conducted them

Who is behind the mysterious lab?

Flora & Fauna of Aotearoa and Clean Green New Zealand Trust won’t publicly name the laboratory saying: “For the security and safety of the independent chemists involved, the identity of the laboratory has been withheld.”

Newsroom asked for the identity of the laboratory to check its credentials and agreed not to disclose the name.

A name was given to Newsroom by a caller claiming to represent the laboratory. The caller said the laboratory has around 3000 metres of space over three sites.

Despite being supplied a name and having the letters spelled out, Newsroom has been unable to verify details of the laboratory.

The supplied name is not in a register of New Zealand companies.

The press release from Flora & Fauna of Aotearoa and Clean Green New Zealand Trust says the laboratory is accredited with 17025 accreditation. This is accreditation given to laboratories deemed to the technically competent. Newsroom could find no record in the New Zealand IANZ directory for the name given.

The name given is also not on a list of New Zealand laboratories with IANZ accreditation to test for fluoroacetate. Accredited laboratories include Landcare Research, Analytica Laboratories, AsureQuality, MilkTest NZ and QEC.

The caller claimed to have purchased ‘standards’ from supplier Sigma Aldrich to test against. Newsroom has queried whether Sigma Aldrich has rules around the supply of 1080 standards.

Searches for content of a website associated with the laboratory name supplied show no content visible in various snapshots taken by an internet archiving service from 2010 to 2019.

An attempt to clarify whether the name supplied - and spelled out - is correct has been made. A spokesperson from Clean Green New Zealand Trust responded:

“I can assure you that the laboratory is a registered NZ company - and trades under the name you have been given. Sometimes these names are different, as you know.”

Queries over the results

University of Otago Dr Belinda Cridge is a lecturer and programme director of the department of pharmacology and toxicology. She is currently funded to conduct research to develop safer alternatives to 1080 and pest control poisons.

"Having seen both reports I have several questions around the processes used in the second (positive) toxicology screen which bring the final results into question ...

"Performing the test for 1080, and in particular fluorocitrate, is complicated and requires a very high degree of technical expertise. My understanding is that the laboratory at Landcare are currently the only group in New Zealand who have sufficient expertise and experience with the test to perform the analysis at short notice.

The press release mentions the methodology of testing was based on the Pitt protocol however, a reference article detailing this protocol is not included.

“There are multiple mistakes in the method as presented which may be a simple error but can’t currently be cross-checked.”

One thing she’s surprised by is the detection of fluorocitrate in tissue.

“This is a difficult measurement to achieve in biological samples, again further specific details on the method used would be very useful.”

She’s also surprised by the levels of fluoroacetate which she said are “significantly higher” than she would expect and wonder if the laboratory has a view on why these would be so high.

She also queries the fluorocitrate levels.

“Is there an additional error in the reporting of the fluorocitrate results? These are presented as being higher than the fluoroacetate levels which is not expected.”

Normally only a small proportion of fluoroacetate gets converted to fluorocitrate.

The test results also were based on the stomach, or in some cases the intestines, of creatures other than the starfish. This also has her puzzled as conversion from fluoroacetate to fluorocitrate is not widely-known to occur in stomach.

"For these reasons I am reluctant to fully support the new results until we receive a detailed description of all the methods and controls used by the second laboratory. The results that were published contain several very unusual findings which are in direct conflict with all published studies to date which means that an open and robust scientific discussion needs to take place. We need to determine why such anomalous results may have occurred and assess any further downstream implications."

University of Auckland associate professor Malcolm Tingle also looked over the results. He thought the method of testing for all three substances seemed reasonable but felt more information was needed to assess whether the results sounded reasonable. He would like to have seen data where proven exposure is linked to a known outcome.

"In summary, without considerably more data, a wisp of a smoking gun, but a lot more science would be needed."

Responses from Flora & Fauna of Aotearoa and Clean Green New Zealand Trust

The use of the US company’s form is “standard practice” according to the response which said when examples of documentation templates are accessible, there’s little point reinventing the wheel.

In answer to a question asking why duplicate tests weren’t completed as would be expected, Newsroom was told some documentation has been withheld and the results given were an average obtained.

The response to Cridge’s query relating to the Pitt protocol was: “The full list of relevant citations and the analytical technique for extraction and analysis may be released in confidence to persons qualified to assess its validity properly.”

When asked about the high level of fluoroacetate the response was the chemist overseeing the analysis is not a toxicologist and this was outside their sphere of expertise.

In response to the question about the high levels of fluorocitrate in the stomach the response given was:

“Fluoroacetate is water soluble, and metabolises to fluorocitrate - this is the true poison through Krebs cycle disruption. The bodies had been in the water for a period of time, possibly less time than those taken by DoC staff for their analysis.”

The groups think the test results are cause to halt current 1080 poisoning operations.

"Flora and Fauna of Aotearoa and Clean Green NZ Trust, along with their volunteer supporters and many thousands of concerned New Zealand citizens, are calling on the government to act now to protect public health by initiating an immediate independent investigation into this tragic incident and stopping all aerial 1080 poison operations before more wildlife are harmed."

Newsroom is continuing to attempt to clarify the name of the laboratory.

Read more:

What killed the Westport rats

Rat-aclysm tests forest defences