Rat results questioned
A scientist has questioned positive 1080 results in dead rats tested at an unnamed laboratory by an environmental group.
Locals and Department of Conservation (DOC) staff picked up almost 700 rats as well as dead Westland petrels, weka, octopus, starfish, a goat, crabs, crayfish and skates after they washed up on Westport’s North Beach this month.
DOC initially speculated that the rats may have died as the result of an aerial 1080 drop 140 kilometres inland, and were washed down rivers in heavy rain. But testing of eight dead rats and a weka by Maanaki Whenua Landcare Research found no 1080 residue.
Massey University’s School of Veterinary Science could not determine the cause of death.
Flora and Fauna of Aotearoa and Clean Green New Zealand Trust said it had had some of the dead wildlife tested at an unnamed lab and found that they had been poisoned by 1080.
Landcare Research tested
the dead rats for the chemical fluoroacetate, or 1080, while the conflicting lab report claims to have tested for both fluoroacetate and fluorocitrate – the chemical created when 1080 is metabolised in the body.
The two campaign groups said samples from four of the five rats tested positive for three chemical markers of 1080, including fluorocitrate. A weka, two shearwaters and a starfish also tested positive for fluorocitrate.
Trustee Ursula Edgington questioned why DOC’s tests looked for fluoroacetate but not fluorocitrate. She said the trust did not want to name the laboratory for its safety.
Belinda Cridge, of the University of Otago’s department of pharmacology and toxicology, said she had read both reports. She had several questions about the processes used in the trust’s testing, and questioned its final results.
‘‘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,’’ she said.
Cridge said she could not support the positive results without a detailed description of all the methods and controls used.
‘‘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.’’
DOC West Coast operations director Mark Davies suggested that the rats died while crossing flooded waterways in search of food.
He said that if the animals had been exposed to 1080, this would have been picked up through the tests.