Meaduring thoron (220Rn) in natural waters
We have been using radon-in-air monitors coupled together with a water-air exchanger to measure 222Rn in coastal waters as a tool to locate and quantify direct groundwater discharge into the sea. Recently, we began to investigate the possibility of making concurrent analysis of 220Rn (thoron, t1/2= 56 s) to “prospect” for points of entry. While the half-life of thoron makes its assay sensitive to variations in air and water flow rates, the short half-life is also an advantage because its detection ensures that one must be close to a source. Another useful application of thoron analyses in water is to locate radium-rich deposits that develop in oil/gas and water supply pipelines. This can be done via 220Rn analysis at points along a pipeline, or at a single site while varying the water flow rate. Determination of the precise location of radioactive scale could avoid expensive and unnecessary remediation or at least affect distribution system maintenance programs. We present here the theoretical basis and some examples from public water supplies in New Jersey where some thorium-series radioactive decay products were already known to be elevated. We present a system for making continuous thoron-in-water measurements and show how one can estimate the volume, distance, and source strength of the contamination.
Additional publication details
|Publication type||Book chapter|
|Publication Subtype||Book Chapter|
|Title||Meaduring thoron (220Rn) in natural waters|
|Publisher||Royal Society of Chemistry|
|Contributing office(s)||New Jersey Water Science Center|