Eels in a South Taranaki waterway contaminated with the residue of potentially carcinogenic firefighting foam are of little risk to humans if eaten, researchers have found.
The paper, published in the New Zealand Medical Journal, looked at the risk of PFOS (Perfluorooctanesulfonic acid) residues in eels for Māori consumers and found it to be insignificant.
The area it chose to investigate, the Ōaonui Stream, is an area found to have elevated levels of the chemicals associated with firefighting foam.
University of Canterbury professor of toxicology Ian Shaw said eels were a food source of interest because their lifespan and fat content meant they contained higher levels of PFOS compared with other plants and animals living in the waterways.
Prof Shaw said it was important when looking at chemicals and food safety to choose a focus group.
"When I look at eels, they are a very important food of Māori, it's traditional to eat [it in the] community, so if there are any contaminants of higher levels in eels, we need to see what the implications are for people whom might eat them more," he said.
The research investigated the safety of an individual consuming about 1kg a year of the eels, while taking into consideration the variations in consumption throughout the year.
Using the average body weight of 70kg, researchers found the Māori dose is about 0.0001 percent of the 'carcinogenic' dose in rats.
The yearly intake of eel in a single meal would be 0.02 percent of the 'carcinogenic' rat dose.
Prof Shaw said there was still a lot of controversy about the carcinogenicity of these chemicals found in firefighting foam.
"There is a lot of controversial, contradicting evidence, and the regulatory authorities look to be erring on the side of safety, so they've used a very safe level, just in case that data is positive," he said.