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St. Petersburg Coastal and Marine Science Center

St. Petersburg Coastal and Marine Science Center > Research and Support Capabilities

Research and Support Capabilities at the St. Petersburg Coastal and Marine Science Center

Shipboard Operations

Radon Detection in Coastal Marine Environments

   Bill Simmonds and Don Rossenberry
Bill Simmonds (left, USGS/Tacoma, WA) and Don Rossenberry (right, NRP/Denver) are assisting in the collection of surface water Radium isotope samples by 'fluffing' the Manganese fiber. The fiber is placed in a small flow-through canister and a known volume passed across the fiber. [larger version]
The distribution of groundwater inputs into coastal surface water can be mapped by utilizing natural sources of the stable isotope 222Radon in coastal environments. Radon-222 is an inert gas that forms from the decay of Uranium in sediments. This natural groundwater-tracer allows hydrogeologists and geochemists to define sources and mechanisms of groundwater/surface water interactions in coastal, lacustrine, and riverine environments.

The 222Radon (222Rn) in the water is measured with a commercially available Radon Detector built and sold by Durridge Company Inc. The unit is called a RAD7 and has the following The activity of 222Rn in the water column is determined with an air-water exchanger and application of known calculations to data output from the RAD7 unit.

Radon data are typically collected in two fashions: (1) continuous mode and (2) stationary mode. The RAD7 units are placed on a boat and water is pumped up and through the air-water exchanger during continuous mode Radon mapping. Data from the RAD7 unit is synchronized with GPS to map and evaluate changes in radon along a shoreline. Stationary radon sampling can be used to evaluate the response of the groundwater discharge/recharge to tidal events. The stationary mode provides detailed radon variations with changes in tides and factors such as wind, rainfall, and surface water currents.


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Page Last Modified: April 29, 2014 @ 12:48 PM (JSS)