Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan

Radiological characterization related to lithology and risk assessment of bottled natural mineral water

The enhancement of natural radioactivity in groundwater, specifically in natural mineral water, is related to the lithological formations through which water bodies or courses pass. Although natural mineral waters are exempt from monitoring for radioactive substances according to Council Directive 2013/51/EURATOM, this study focuses on the radiological characterization of natural mineral water under Spanish Royal Decree 3/2023. The water studied was taken from Catalan aquifers with different lithological characteristics (sedimentary, metamorphic or granitic) and is sold on local markets. Moreover, radiological data on the water was correlated with its lithological origin and the health risk for different age groups was assessed. Our results showed that of the 26 natural mineral waters studied, 10 exceeded gross alpha screening value (100 mBq/L), all from granitic aquifers. Further research on natural individual radionuclides was conducted on these ten samples. 234U and 238U were at around 1100-1600 mBq/L. In addition, 210Pb was found in two samples, which also presented the highest 226Ra activity, associated with granitic bedrock and the presence of 210Po. The annual effective dose was 179.0 µSv/year and 145.9 µSv/year, exceeding 100 µSv/year mainly due to the contribution of 210Pb > 234,238U > 210Po > 226Ra, in this order. After assessing the lifetime cancer risk, these two samples were determined not to pose a health risk due to ingestion. Although no radiological monitoring is required for natural mineral water, further surveillance is recommendable.

Assessment of radiation dose due to 210Po in water and food samples of Chamarajanagar district, Karnataka, India

Groundwater is in direct contact with the soil and rocks that dissolve many compounds and minerals including uranium and its daughter products. 210Po is one of the decay products of 238U series that cause internal radiation dose in humans when consumed in the form of water and food, including sea food. Therefore, activities of 210Po have been studied in ground and surface water, and in food samples that are commonly used in Chamarajanagar region of Karnataka, India. The average 210Po concentration in bore well water samples and surface water samples are 3.21 and 1.85 mBq L-1, respectively. In raw rice and wheat, the average values of 210Po are 96 and 41 mBq kg-1, respectively. In millets and pulses, the average activity of 210Po is 157 and 79 mBq kg-1, respectively. Among food items, the highest activity of 1.3 kBq kg-1 is observed in marine crabs and the lowest activity of 2.6 mBq kg-1 is found in milk samples. The average ingestion dose due to 210Po in ground and surface water are 2.8 and 1.62 μSv y-1, respectively. The ingestion dose due to various food samples to the population is also calculated. Total ingestion dose due to 210Po to pure vegetarian population and general population are 38.09 and 590.80 μSv y-1, respectively. The concentration of 210Po in water samples and food samples of this region are in a comparable range with the world and Indian average values and lies well below the recommended guideline level.

Levels of naturally occurring radioisotopes in local and imported bottled drinking water available in Québec City, Canada

Consumption of local and imported bottled water in Canada has greatly increased during the past three decades. While the presence of natural radioactivity is often overlooked when dealing with the water quality of these bottled products, it could contribute substantially to the uptake of radionuclides especially when sourced from regions with higher radioactivity levels compared to where it is consumed. In this study, the activity of several naturally occurring radionuclides (i.e., 210Po, 226,228Ra, 230,232Th, 234,235,238U) were measured in bottled water available in Québec, Canada after sample pretreatment and analysis by either radiometric or mass spectrometry approaches. 230,232Th and 228Ra concentrations were below minimum detectable activity levels in all samples tested. Analytical results for 234U, 235U, 238U, and 226Ra showed concentrations that ranged from 0.38 to 115 mBq/L, (2.2-313) x 10-2 mBq/L, 0.48-58.4 mBq/L, and 1.1-550 mBq/L, respectively. 210Po was detected in only 5 samples and its activity ranged from 2 to 26 mBq/L. To determine variability in activity within brands, the same brands of bottled water were purchased during two consecutive years and analyzed. The possible radiological impact of the consumption of these types of water was assessed based on different drinking habit scenarios. Some of the imported water brands showed higher activity concentrations than local sources or tap water, suggesting that individuals drinking predominantly imported bottled water would receive a higher radiation dose than those who drink mainly local water.

Assessment of internal radiation exposure caused by radon in commercially bottled spring waters consumed in Turkey

The variation of dissolved radon levels in water supplies remains of interest since radon ingested through drinking water can give considerable radiation to the lining of the stomach. This study aims to determine the radon concentration levels in bottled spring drinking water (BSW) brands commercially sold in Turkey using a radon gas monitor and to assess the internal radiation exposure caused by the ingestion and inhalation of radon. The activity concentrations of radon analyzed in 77 BSW brands varied from 7.1±0.8 to 28.7±2.7 mBq/L with an average of 15.7±5.1 mBq/L. The total annual effective dose was estimated to assess the radiological risk for three age groups in four different scenarios based on annual drinking water intake. All estimated dose values are well below the recommended reference dose of 100 µSv for drinking water. Therefore, radon gas in the investigated BSW samples poses no significant radiological risk to the public.

Natural Radionuclides in Bottled Mineral Waters Consumed in Turkey and Their Contribution to Radiation Dose

Bottled natural mineral water (BMW) consumption in Turkey is increasing every year. Depending on the local geology from which the water is extracted, BMW could be enhanced with natural radionuclides. In this study, the activity concentrations of natural radionuclides in 58 BMW samples of 25 different brands marketed in Turkey were measured using a γ-ray spectrometer with high-purity germanium (HPGe) detector. The average activity concentrations of 226Ra, 228Ra, and 40K in BMW samples were found as 0.4, 0.5, and 4.3 Bq/L, respectively. The activity concentrations of 228Ra exceeded the WHO-recommended maximum permissible limit of 0.1 Bq/L for drinking water. The annual effective dose (AED) and excess lifetime cancer risk (LCR) caused by the ingestion of each BMW sample were estimated for adults to assess radiological risks using two different scenarios based on BMW consumption rates (150 and 13 L/y). All estimated total AEDs, except for two samples, were below the guidance dose level of 100 μSv/y recommended by the World Health Organization (WHO) and Turkish regulations for drinking water. For all BMW brands, 228Ra was found as the main contributor to the AEDs. The LCR values were lower than the acceptable value of 10-3 for radiological risks.

222Rn and 226Ra Concentrations in Spring Water and Their Dose Assessment Due to Ingestion Intake

²²²Rn and ²²⁶Ra concentrations of less than a few to several thousands of Bq L⁻¹ have been observed in several underground bodies of water around the world. Although regulations for these concentrations in water have been implemented internationally, there are currently no regulations in place in Japan. However, concentrations that exceed these internationally recognized regulatory values have also been observed in Japan. In this study, concentrations in spring water in the northern part of Japan were measured and the effective dose from intake of the water was evaluated. ²²²Rn concentrations were measured using a liquid scintillation counter, and ²²⁶Ra concentrations were measured using a high purity germanium detector after chemical preparation. The measured ²²²Rn concentrations (=12.7 ± 6.1 Bq L⁻¹) and ²²⁶Ra concentrations (<0.019–0.022 Bq L⁻¹) did not exceed the reference values set by international and European/American organizations. A conservative estimate of the annual effective ingestion dose of 8 μSv for ²²²Rn and ²²⁶Ra obtained in this study is much smaller than the estimated overall annual effective dose of 2.2 mSv from natural radiation to the Japanese population. However, this dosage accounts for 8% of the WHO individual dosing criteria of 0.1 mSv/year for drinking water.

Assessing contribution of bottled water in nutrient absorption using the bottled water nutritional quality index (BWNQI) in Iran

In this study, the contribution of bottled water in the absorption of nutritional minerals in Iran has been investigated. To calculate the nutritional quality index of bottled water (BWNQI) and evaluate the contribution of bottled water in nutrient absorption; the concentration of nutrient minerals, the standard level of these elements in bottled water, the recommended amount of nutrient mineral and the total consumption of drinking water in different age-sex groups were analyzed. The results showed that the average contribution of bottled water in absorbing the recommended amount of the nutrients of fluoride (F), magnesium (Mg), calcium (Ca), sodium (Na), copper (Cu), zinc (Zn) and manganese (Mn) was 12.16, 4.98, 4.85, 2.12, 0.49, 0.33 and 0.02%, respectively. According to the BWNQI index, the bottled water quality was as follows: 53.5% poor, 36.6% marginal, 7% fair, 2.81% good. Although most of the bottled water studied in this research were mineral water, a significant portion of them had poor nutritional quality, so the addition of minerals needed by the body through bottled water should be given more attention by the bottled water manufacturers and suppliers.