We smell a rat when one laboratory report says testing has detected 1080 in dead rodents collected on the West Coast, contradicting the findings of another laboratory report which found no evidence of the controversial poison.
The identity of the laboratory which produced the first-mentioned report is being kept confidential “for the security and safety of the independent chemists involved … ”
The secret lab’s findings challenge the Department of Conservation insistence that 1080 was not found in any of the wildlife tested by Landcare Research and Massey University veterinarians.
Who should we believe?
The Science Media Centre asked for help in tackling that question by asking for comment from Dr Belinda Cridge, in the Department of Pharmacology and Toxicology at University of Otago. Her observations can be read HERE.
The use of 1080 to eradicate pests is politically contentious, although in 2011 the Parliamentary Commissioner for the Environment Dr Jan Wright, released a report investigating the use of 1080 – Evaluating the use of 1080: Predators, poisons and silent forests.
In the report Dr Wright recommended against a moratorium on 1080, citing the damage that would be done to native forests and animals if a ban went ahead.
But two non-profit environmental groups, Flora & Fauna of Aotearoa and Clean Green New Zealand, disagree.
This week they published test results indicating that 1080 poison was the likely cause of death “at an environmental catastrophe in Westport”.
This refers to the discovery on November 9 of dead wildlife washed down the flooded Buller River one week after a Department of Conservation aerial 1080 poison operation 140 kms upstream,
The environmental groups’ press statement says:
“Hundreds of potentially toxic carcasses of rats, a goat, birds and numerous aquatic species were strewn across the public beach at Westport. The full results of tests undertaken by an independent laboratory1, using the latest methodology and equipment, include samples taken from 5 rats, 1 weka, 2 shearwaters, 1 starfish and 6 mussels.
“The samples from 4 of the 5 rats tested positive for three chemical markers of 1080 poison, including the toxic chemical, fluorocitrate. This was also the case for both the shearwater birds. “The starfish and weka also tested positive for fluorocitrate.
“There were no traces of 1080 detected in the mussels.
“The tests included stomach and intestines of samples extracted from carcasses collected from the beach and Buller River by volunteers”
But the environmental groups’ press statement says the identity of the laboratory has been withheld “for the security and safety of the independent chemists involved”.
There is no secret about who did the testing for the Department of Conservation.
Its press statement, on November 20, said Maanaki Whenua Landcare Research tested eight dead rats and one weka.
None of these animals had any residue of 1080 toxin. Two other rats were too decomposed to test.
Massey University School of Veterinary Science undertook post-mortem examinations of five of the dead rats but could not determine their cause of death. The weka was also examined with cause of death unknown.”
DOC West Coast Operations Director Mark Davies says the test results confirm that the rats washed up on the beach are unlikely to have come from an area where 1080 had been used.
“We don’t know the source of the dead rats but it’s possible they came from beech forest areas closer to Westport in the Buller Gorge, affected by flood conditions.
“Rat numbers have exploded in beech forests due to heavy seeding and now seed is germinating, they are desperate for food, which can drive them into new areas and cause them to cross waterways,” says Mark Davies.
“Predator control is critical to protecting our most at-risk population of native wildlife as rats turn to eating native birds and bats and their young this spring and summer.”
DOC sent ten rats for testing. Five went to Massey University for post-mortem and five to Maanaki Whenua Landcare Research for toxicology testing.
After post-mortem, the five rats were also sent to test for 1080 although two were too decomposed to do this. The weka was also sent for post-mortem and 1080 testing.
DoC says it’s likely the marine animals which also washed up near Westport were victims of prolonged stormy weather at the time, which can have a negative impact on marine life.
Read the toxicology and pathology reports HERE.
The contradictory results – the environmental groups’ press statement contends – raise serious questions about the methodology employed by the laboratories commissioned to undertake DoC’s testing.
They say the full results of the independent tests will be made publicly available on Flora and Fauna of Aotearoa’s website and copies sent to relevant government agencies and MPs.
Flora and Fauna of Aotearoa and Clean Green NZ Trust called on the government to initiate an immediate independent investigation into the incident and stop all aerial 1080 poison operations before more wildlife are harmed.
Dr Belinda Cridge, Department of Pharmacology and Toxicology, University of Otago, responded to a request for comment from the Science Media Centre.
Having seen both reports, she raises 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 method used by the second lab is referenced as Pitt (2015), I couldn’t find a corresponding article for this reference. There are multiple mistakes in the method as presented which may be a simple error but it can’t currently be cross-checked. The fluorocitrate results are presented as being higher than the fluoroacetate levels which is not expected. Additionally, the report shows that the stomach contents were analysed, and there were high levels of the fluorocitrate in the stomach reported, yet conversion to fluorocitrate from fluoroacetate tends to be minimal in this organ.”
“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.”
In a conflict of interest declaration, Dr Cridge says she is being funded to conduct research to develop safer alternatives to 1080 and other pest control poisons. In the close network that is NZ science she is acquainted with, but has not collaborated or worked with, the team at Landcare NZ.