Radioactivity in drilled and dug well drinking water of Ogun state Southwestern Nigeria and consequent dose estimates

The status of natural radioactivity in Nigerian environments

Proper documentation of baseline radiation data of different environments is an important step toward adequate environmental monitoring, and it provides quick means to quantitatively check and determine possible radionuclide contamination by anthropogenic sources. Besides, such documentation is useful for decision making processes, assessment of dose rates to the public, epidemiological studies, and environmental regulations. This review summarizes the results of studies conducted on radioactivity in Nigerian environments. For most soil samples, the levels of radioactivity are well within the world averages of 33, 45, and 420 Bq kg^-1 for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. Other soil samples from regions such as Abeokuta in the southwest, and Jos in the northcentral have been described as high background radiation areas with radioactivity values comparable with those obtained from known high background radiation areas such as the Odisha (formerly Orissa) coast in India (with values reported as 350, 2,825, and 180 Bq kg^-1 for ²³⁸U/²²⁶Ra, ²³²Th, and ⁴⁰K, respectively). In some parts of Nigeria, surface and underground water sources used for drinking and other purposes also present elevated levels of ²²⁶Ra above the world range of 0.01 to 0.1 Bq l^-1 and the tolerable levels recommended by the World Health Organization and U.S. Environmental Protection Agency. Corresponding radiation doses due to measured radioactivities from different environments were estimated and compared with those reported in similar studies around the world. More so, the human and environmental health hazards that might be associated with the reported radioactivity in different environmental settings are discussed. The present report is expected to support authorities in developing appropriate regulations to protect the public from radiation exposure arising from environmental radioactivity. The report also examines other areas of consideration for future studies to ensure adequate radiation monitoring in Nigeria.

Evaluation of Radiological Health Risks in Popularly Consumed Brands of Sachet Water in Nigeria

Radiological investigation of 35 brands of most popularly used sachet drinking water in Ondo state, Nigeria has been carried out using a spectrometric method for evaluating the concomitant health risks to the members of the public. Activity concentrations of the investigated radionuclides ⁴⁰K, ²²⁶R, and ²²⁸Ra were in the range from 16.35 ± 4.10 to 199.94 ± 38.40 Bq L⁻¹ with an arithmetic mean (AM) of 66.22 ± 54.99 Bq L⁻¹, from 1.35± 0.79 to 17.06 ± 5.13 Bq L⁻¹ with an AM of 6.88 ± 3.66 Bq L⁻¹, and from 1.95 ± 0.08 to 17.22 ± 3.87 Bq L⁻¹ with an AM of 9.49 ± 4.98 Bq L⁻¹, respectively. The determined annual effective doses and the corresponding excess lifetime cancer risks due to ²²⁶Ra and ²²⁸Ra were found to exceed the acceptable limits of 0.1 mSv y⁻¹ and 10⁻³ respectively, as suggested by the World Health Organization (WHO). This implies a non-negligible carcinogenic health hazard due to the intake of the surveyed drinking water, especially for the lactating babies (0–1) y and teenagers (12–17) y. The data from this research may form an invaluable component of radiometric values of the database in Nigeria, as well as the world for setting up guidelines and control policies for the use of sachet water.

Gross alpha and beta measurements in drinkable water from seven major geographical regions of China and the associated cancer risks

In this study, human health risk derived from radioactive pollution in drinking water of China was assessed based on gross alpha and beta. Considering the presence of numerous data under the detection limits, the left-censored handling methods were employed to deal with the non-detected values in gross alpha and beta radioactive concentrations. Results show that concentrations of gross alpha and beta range from 4.98 × 10^-4 Bq/L to 0.49 Bq/L with a mean value of 0.029 Bq/L and 5.00 × 10^-3 Bq/L to 1.26 Bq/L with a mean value of 0.091 Bq/L, respectively. With the average effective dose being 1.41 × 10^-2 mSv/y, the annual cancer risk due to radioactive pollution in Chinese drinking water is 7.75 × 10^-7 /y. This study aimed to provide an easier method to quantify the radioactive pollution in drinking water and give a scientific basis for making policy decisions on radioactive pollution management.

Assessment of natural radioactivity and consequent radiological hazard in different brands of commercialized bottled mineral water produced in China

As one of the drinking water quality parameters, natural radioactivity parameters are recommended to prevent a potential health threat to the public. In this study, the gross-α and gross-β activity concentrations in 15 different brands of commercial bottled mineral water consumed in China were analyzed to evaluate the quality and corresponding health impact on the population. The activity concentrations of gross-α and gross-β in different samples varied from 4.4 to 130.6 and 17.3-320.3 mBq L^-1, respectively. The values of the annual effective dose equivalent rate (AED) for infants, children and adults ranged from 1.3 to 21.6, 2.9-52.5 and 5.5-97.8 μSv y^-1, respectively. The average excess lifetime cancer risk caused by the consumption of bottled mineral water samples was estimated as 6.0 × 10^-5. These results show that all the measured gross-α and gross-β are found to be obviously less than the guidance level by WHO and the domestic standard. The values of AED are below the World Health Organization (WHO) recommended limit of 0.1 mSv y^-1. Combined with the lifetime cancer risk assessment, it is concluded that there is no significant risk for consumption of the observed brands of bottled mineral water and it can be consumed safely.

Radon in harvested rainwater at the household level, Palestine

The main objective of this study was to assess Radon concentration in the harvested rainwater (HRW) at the household level in Yatta area, Palestine. HRW is mainly used for drinking as it is the major source of water for domestic uses due to water scarcity. Ninety HRW samples from the household cisterns were collected from six localities (a town and five villages) and Radon concentrations were measured. The samples were randomly collected from different households to represent the Yatta area. Fifteen samples were collected from each locality at the same day. RAD7 device was used for analysis and each sample was measured in duplicate. Radon concentrations ranged from 0.037 to 0.26 Bq/L with a mean ± standard deviation of 0.14 ± 0.06 Bq/L. The estimated annual effective radiation doses for babies, children and adults were all far below the maximum limit of 5 mSvy^-1 set by the National Council on Radiation Protection and Measurements.

Natural radionuclides in bottled drinking waters produced in Croatia and their contribution to radiation dose

Activity concentrations of (234)U, (238)U, (226)Ra, (228)Ra, (210)Po and (210)Pb in all Croatian bottled drinking natural spring and natural mineral water products, commercially available on the market, were determined. The samples originated from various geological regions of Croatia. Activity concentrations of measured radionuclides are in general decreasing in this order: (234)U>(238)U>(226)Ra>(228)Ra>(210)Pb>(210)Po and (226)Ra>(228)Ra>(234)U>(238)U>(210)Pb>(210)Po for natural spring and mineral waters, respectively. Based on the radionuclide activity concentrations average total annual effective ingestion doses for infants, children and adults, as well as contribution of each particular radionuclide to total dose, were assessed and discussed. The highest doses were calculated for children from 7 to 12 years of age, which makes them the most critical group of population. All values for each type of water, as well as for each population group, were well below the recommended reference dose level (RDL) of 0.1 mSv from one year's consumption of drinking water according to the European Commission recommendations from 1998. Contribution of each particular radionuclide to total doses varied among different water types and within each water type, as well as between different age groups, where the lowest contribution was found for uranium isotopes and the highest for (228)Ra.

Measurements of 222Rn activity concentration in domestic water sources in Penang, northern peninsular Malaysia

Measurements of (222)Rn activity concentration were carried out in 39 samples collected from the domestic and drinking water sources used in the island and mainland of Penang, northern peninsular, Malaysia. The measured activity concentrations ranged from 7.49 to 26.25 Bq l(-1), 0.49 to 9.72 Bq l(-1) and 0.58 to 2.54 Bq l(-1) in the raw, treated and bottled water samples collected, respectively. This indicated relatively high radon concentrations compared with that from other parts of the world, which still falls below the WHO recommended treatment level of 100 Bq l(-1). From this data, the age-dependent associated committed effective doses due to the ingestion of (222)Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from (222)Rn resulting from 1 y's consumption of these water were estimated to range from 0.003 to 0.048, 0.001 to 0.018 and 0.002 to 0.023 mSv y(-1), for age groups 0-1, 2-16 and >16 y, respectively.