Radiological risk assessment of outdoorRn andRn around rare earth element and uranium mines from northern Vietnam.

The outdoorRn andRn concentrations at 320 sampling points at 1 m above the ground in different sites surrounding rare earth element (REE) and uranium mines from northern Vietnam were measured using the RAD7. Results showed thatRn concentrations were always higher thanRn concentrations with large variation ranges from 25.7 to 573 Bq mand from 18.5 to 385 Bq m, respectively. The high correlation betweenRn andRa concentrations in surface soil of the studied sites were observed. The highestRn andRn concentrations are found at the sampling points of the REE NX-Lai Chau site. TheRn andRn activities surrounding the REE mines were found to be higher than those surrounding the uranium mines. The average annual committed effective doses originated from the inhalation ofRn andRn outdoor concentrations is about five times higher than the worldwide average value.