Contamination of ²²⁶Ra radionuclide in well water, associated health risks and long-term behaviors in agricultural soils: a case study in Phu Yen province, Vietnam

Flexpart Sixty samples of well water were collected in a coastal area of Phu Yen province, Vietnam for ²²⁶Ra analysis. Activity concentrations of ²²⁶Ra (A-²²⁶Ra) were found from 1.7 to 159 mBq L^-1 with the average value of 5.44 mBq L^-1. The results showed that A-²²⁶Ra in well water samples related to the topographical conditions of sampling locations and types of well. The values of A-²²⁶Ra, effective dose and excess lifetime cancer risk did not exceed their recommended values. Long-term change of A-²²⁶Ra in agricultural soils due to well water irrigation was based on model assessment. The results showed that A-²²⁶Ra increased continuously under the cultivation process including water irrigation and fertilizer application. However, it got an equilibrium value after a certain period of the agricultural cultivation. This period correlated with A-²²⁶Ra in irrigation water and A-²²⁶Ra partition lost by processes of volatilization, leaching, radioactive decay and plant uptake. (author)