Uranium and radium isotopes in some selected thermal, surface and bottled waters in Vietnam

210Po characteristic in selected thermal water sources in Northern Vietnam

There are eight famous thermal water sources, with medium temperature, neutral pH, high ranges of TDS values located in different carbonate formations in Northern Vietnam. The chemical composition results showed the major elements present were Na, K, Mg, Ca, Sr, while trace amounts of rare earth elements (REE), Ag, As, Pb, Th, U were observed. The 210Po activity concentration and the annual committed effective doses for adults, children, and infants in all study areas were far less than 100 mBq L−1 and 0.1 mSv y−1, respectively. Some significant correlations between 210Po and other chemical components have been observed.

Study of Well Waters from High-Level Natural Radiation Areas in Northern Vietnam

The determination of natural radionuclide concentrations plays an important role for assuring public health and in the estimation of the radiological hazards. This is especially true for high level radiation areas. In this study, ²²⁶Ra, ²²⁸Ra and ²³⁸U concentrations were measured in well waters surrounding eight of the high-level natural radiation areas in northern Vietnam. The ²²⁶Ra, ²²⁸Ra and ²³⁸U activity concentrations vary from <1.2 × 10^-3-2.7 (0.46), <2.6 × 10^-3-0.43 (0.07) and <38 × 10^-3-5.32 Bq/L (0.50 of median), respectively. ²²⁶Ra and ²³⁸U isotopes in most areas are in equilibrium, except for the DT-Thai Nguyen area. The calculated radiological hazard indices are generally higher than WHO (World Health Organization) recommendations. Average annual effective dose and excess lifetime cancer risk values due to drinking well water range from to 130 to 540 μSv/year and 7.4 × 10^-6 to 3.1 × 10^-5, respectively.

Gross alpha/beta activity concentrations in spa and mineral waters in North Vietnam

There is little available information on the radioactivity concentrations in the thermal and drinking water sources in North Vietnam. In the current study, the gross alpha and gross beta activity concentrations were determined in 8 water sources in the area. The average activities of gross alpha and beta in the 8 sources are 38.7 mBq L− 1 and 88.0 mBq L− 1. These activity concentrations are lower than WHO recommendations for drinking water. In this study, the gross alpha and gross beta show a weak correlation.

Assessment of radioactivity and chemical contaminants in domestic water at supply stations in Long Phu District, Vietnam, to prevent public health risks

This paper presents information on the concentration of radioactivity and chemicals at 12 water stations that used groundwater as their raw water supply source. The groundwater's radioactivity was higher than the treated, tap, and surface water, but lower than the national and international recommendations. At five stations (41.7%), the gross alpha contents were higher than the levels advised by Vietnam's regulations, but met the WHO and IAEA's recommendations. The mean activity (Bq L^-1) gross alpha, gross beta, Ra-224, Ra-226, and Ra-228 were 0.093 ± 0.012, 0.221 ± 0.020, 0.031 ± 0.004, 0.028 ± 0.004, and 0.035 ± 0.001, respectively. The contribution of Ra-226 to the gross alpha was in a range of 23%-60% (r = 0.91, p value <0.001), and the ratio of Ra-226/Ra-228 ranged from 0.49-1.06. For the treated and tap water, each age groups' annual committed effective dose was lower than the international regulations. The concentration of the total dissolved solids, sulfate, chloride, sodium, barium, and manganese met the national regulations. However, during the rainy season, the surface water in the area was affected by saltwater intrusion, with salinity up to 4.1‰. Discriminant analysis was applied to study the differences among the water groups. As a result, the treated and tap water were separated from the others.