The Waikato River won’t become the country’s first glow-in-the-dark river any time soon, according to Environment Waikato’s water sampling.
The Council took a closer look at levels of uranium in the river following claims in two magazines that the radioactive waste was detectable in the water. One German laboratory which tested water had asked how far from the “nuclear power plant” samples were taken, according to the magazines.
But recent Environment Waikato sampling has shown levels in the river are 60 times lower than required for drinking water standards.
Water scientist Bill Vant told this week’s Council Environment Committee that radioactive uranium was a health issue for safe drinking water. It was naturally occurring in soils and could therefore get into water through runoff. Testing in 1980 showed no levels of concern and no need for routine monitoring.
Last year a five yearly survey was being done of heavy metals in the river at five sites from Taupo to Tuakau.
The laboratory which tested the samples used the most sensitive method known, which are able to detect extremely low levels. The testing showed no detectable levels of uranium – less than 0.00002 grams per cubic metre. In November results of one of the 20 samples showed 0.00003, just above detectable limits. The drinking water standard is 0.002.
Mr Vant said there were no known sources of uranium waste in the Region and Environment Waikato was working with fertiliser manufacturers to find out more about the magazines’ findings and the German sampling.
Dr Ants Roberts of AgResearch and Dr Hilton Furness of the New Zealand Fertiliser Manufacturers’ Research Association also presented a report to the Committee on uranium in soils, which said at the background levels present in New Zealand soils presented no danger to human health.
The levels of uranium in New Zealand soils at 1.5 parts per million placed the country at the lower end of international rankings. Russia had 3.8 ppm, while US levels were double New Zealand’s and in Britain they were 70 percent higher.
Uranium occurred naturally in phosphate rock, which was the main ingredient of superphosphate fertiliser. Humans received about five percent of the total radiation they receive through plants, which take it up through the soil.
Dr Roberts said that a 40 year trial of phosphate in the South Island showed that applications at high levels – 376 kg of superphosphate per hectare a year for the next 100 years – would still give levels lower than present levels in Britain, the US and Russia.
This media item was current at its release date. The facts or figures it contains may have changed since its original publication.