Phosphate rich land before mining
Radium-226, a breakdown product of uranium, is present in the phosphate rich ore matrix and the concentration of radium is increased in the processing and reclamation process of the former mines. Radium-226 contamination in the soil presents a source of gamma radiation exposure. This risk is enhanced due to the fact that 1) the concentration of Radium-226 in the reclaimed soil is greater and 2) the mining removes the protective layers of overburden and sand tailings making levels of gamma radiation higher at the soil surface.
Gamma radiation due to Radium-226 contamination in the soil is not shielded and is a source of direct exposure to high levels of radiation.
radon is different
gamma radiation and radon are both due to Contamination with radium-226 but...
Radon is not gamma
Radon is a gas
Radon can be absent, despite high levels of Radium-226 and high levels of gamma radiation
As shown above, radon can be a problem when homes are located on top of land contaminated with high levels of Radium-226 due to seepage and diffusion of the gas through the foundation and building up in the indoor air.
However, gamma radiation levels increased at the soil surface create a cancer risk to anyone present on the property, without a structure to concentrate the radon gas, and independent of elevated levels of radon in the structure
Gamma radiation levels can be directly measured at the soil surface and increase due to the concentration of Radium-226 in the soil and the proximity of that contamination to the soil surface
Starting in 1978, Drummond was told that there was a radiation contamination problem with the land
Nuclear Regulatory Commission rule requires cleanup level down to 25 mrem/year which equates to a 1 in 5000 cancer risk.
At 100 mrem/year the cancer risk is equivalent to 2 in 1000 or 1 in 500.
The high end of EPA acceptable cleanup levels would be 25 mrem/year.
It would be "exceptional" (not for residential uses) to allow for up to 100 mrem/year.
EPA's standard allowable risk that triggers cleanup is 1 excess cancer in 1,000,000 people. Accepting a 1 in 500 cancer risk would be 2,000 times greater than what is normally allowed by the EPA.
Contact us if you have any questions about the levels of gamma radiation on or around your property.
Credits:
Created with images by Scott Clark - "Strip Mining"