Material evidence

By Rebecca Priestley In Health, Science

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27th August, 2005 Leave a Comment

When the community newspaper the Wellingtonian ran a story recently about radioactive waste buried in a suburban park, it appeared to come as news to the Wellington City Council. “New Zealand is nuclear-free, so we didn’t expect anything like that!” exclaimed the council’s Johan Simeonov.

Yet, it was the council that, in 1964, approved the burial of the waste in what was then Wilton tip and is now Ian Galloway Park. There had also been media exposure about it in 1988, and the story has appeared again in three books* in the past few years.

Not that the stuff is illegal. New Zealand’s nuclear-free policy bans nuclear weapons, ships and power – not nuclear science. Licensed importers bring in some 2500 shipments of radioactive material a year – from phosphorus-32 to strontium-90 – for use in medicine, industry and scientific research. And where there are radioactive isotopes, there is radioactive waste.

These days, however, it’s unlikely to be dumped in your local landfill.

The waste buried under Ian Galloway Park consists of three truckloads of furniture and equipment, dumped in 1964 following the discovery of radio-active contamination in Victoria University’s physics department. Back in 1961, a physics technician trying out a new Geiger counter discovered high levels of radioactivity – most likely from careless handling of the radioactive isotope radium-226. The Dominion X-Ray and Radium Laboratory (now the Ministry of Health’s National Radiation Laboratory) surveyed the physics department and removed some contaminated material, which – as was standard practice at the time – was encased in concrete and dumped at sea.

But in 1963, a new radiation monitor revealed further evidence of contamination and a more comprehensive clean-up was ordered. Radioactive contamination was discovered on furniture, equipment, floors, walls, dust and papers. To complicate matters, by 1963 Ron Humphrey, a physics lecturer, had died of leukaemia and his family were suing the university for compensation.

The department was carefully decontaminated and all contaminated material removed to a nearby garage, pending a possible court case over Humphrey’s death. When the case was settled out of court, the material was trucked to the Wilton tip. The cause of Humphrey’s leukaemia was not determined, but post-mortem analysis of his bones – the place where ingested radium becomes concentrated – showed his radium levels were within the normal range.

The 1964 burial hit the news in 1988 when journalist Steven Raea broke the story in Christchurch’s Weekend Star. The headline ran across two pages: Radiation leak: Official cover-up, starting a month-long media frenzy around the country. (The nuclear-free law had not long been passed.) Subsequent tests of the park’s radioactivity, however, showed no activity above normal background levels.

By the time the waste was buried, New Zealand had been importing and using – and disposing of – radioactive isotopes for more than 60 years. Radium was used for cancer treatment soon after its discovery at the turn of the century. It was first used at Victoria University in 1910 when Ernest Rutherford procured a supply for physics professor Thomas Laby, who was investigating the nature of gamma rays. In 1935, the Department of Scientific and Industrial Research imported radioactive cobalt to use in agricultural experiments. After World War II, radioactive isotopes manufactured in nuclear reactors became available and their use in medicine, industry and science boomed.

Until the 1970s, most of New Zealand’s radioactive waste, including contaminated articles such as gloves and equipment, was embedded in concrete and dumped in the Hikurangi Trench, just east of Cook Strait. The physics department waste was of such high volume and low radioactivity, however, that landfill disposal was preferred.

Since 1976, radioactive waste has either been stored at the National Radiation Laboratory in Christchurch or shipped back to its source for recycling or disposal. Today’s handling safety standards are stringent and waste mostly consists of radioactive isotopes that are no longer needed – because their radioactivity has depleted to an ineffective level, or because technology has superseded them. The National Radiation Laboratory’s storeroom is currently home to 161 small drums of radioactive sources sealed in concrete. Although the material is considered potentially harmful enough to be thus isolated, it’s safe enough to be stored within metres of where people work every day. (Radiation from radium-226, for example, is harmful only when the radium is in close or direct contact with the body.) Most of the radioisotopes imported today, however, are short-lived, and decay to a safe level in a matter of days or weeks.

As for the waste in Ian Galloway Park, the total level of radioactivity associated with the material dumped in 1964 was 500 microcuries – about the same amount of radioactivity that could be found naturally occurring in about 150 cubic metres of ordinary clay.

“It is not likely to be harmful,” says the National Radiation Laboratory’s Jim Turnbull. “Most of the furniture will have decayed by now and the radium incorporated into the fill, where the radioactivity will be comparable to that of local soil.”

But just to be safe, the Wellington City Council is planning to test the park’s leachate for elevated levels of radium, and also to do a Geiger counter test of surface radioactivity. High time, perhaps. While organising the 1964 burial, the Dominion X-Ray and Radium Laboratory recommended that “arrangements should be made for the periodic collection of samples of groundwater flowing out below the rubbish tip”. Watch this space for test results.

Rebecca Priestley is writing a PhD thesis on New Zealand’s nuclear and radiation history.

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27th August, 2005 Leave a Comment

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