New research by NIWA scientists shows 1080 poison does not contaminate waterways.
1080 is used throughout New Zealand to control animal pests - mainly possums - which spread the livestock disease bovine tuberculosis.
Over the past three months, scientists have placed large amounts of 1080 in a trial catchment on the West Coast and then simulated rainfall in the area.
The aim is to understand how 1080 - a natural toxin - moves through or across soil into waterways and if the run-off degrades the quality of water.
Dr Alastair Suren is the freshwater ecologist who led the research and says the study found that during rainfall 1080 diluted to the point where it became nearly undetectable.
"We were loading up our tidy study catchments with a lot just to get a signal and we were finding concentrations very, very low - especially when you normalised it back to what you'd expect from one bait.
"So if you were to look at a catchment which has been treated with 1080 under normal conditions, you basically won't be able to detect any 1080 in the soil water, the ground water or the stream water after an operation and after it's rained, which is when the 1080 will leach out from baits."
Dr Suren hopes the study will help to alleviate fears that people and stock can be poisoned by drinking the water near a 1080 drop.
"I think these results hopefully will just help satisfy people that there is an incredibly low chance or no chance of any contamination occurring, especially after a rainfall event."
The research was commissioned by the Animal Health Board which is responsible for the TB eradication programme.
