Radon is a soluble colourless, gaseous, unstable isotope with a half-life of 3.8 days. It is generated as part of the uranium decay series. Uranium is ubiquitous in almost all rocks and soils, resulting in the release of radon from uranium bearing minerals in groundwater.

Radon is abundant in groundwaters but has almost negligible concentrations in surface waters due to rapid radon loss to the atmosphere through degassing. This contrast in radon concentrations between groundwaters and surface waters enables radon to be an ideal tracer to measure groundwater-surface water interaction. Surface waters which have elevated concentrations of radon indicate a location where groundwater is discharging into the surface water.

Radon sampling and analysis is a rapid, cost-effective method for screening long river reaches to identify local groundwater inflows. The liquid scintillation method used in GNS Science water dating laboratory has the advantage over other methods of being able to measure large numbers of samples at once. In addition, this method provides another tool to study the transport of nutrients from farms to streams and rivers. 

How to Submit Radon Samples

  • We send bottles to you, free of charge. Please contact us to request bottles.
  • It is crucial to let us know when the sampling is scheduled to take place, so we can have a counter ready when your samples arrive.
  • Samples must be sent to us immediately on the day of, or day after sampling.
  • Do not send samples to us on Friday (best sampling is Monday to Wednesday). Samples collected during the week must arrive no later than Friday 12pm.

Please read the sampling instructions before taking samples.

Send samples to:

Tritium and Water Dating Laboratory
GNS Science
1 Fairway Drive
Lower Hutt 5010
New Zealand

Contact phone: 04 570 4652, 04 570 4247