Radon-222 (222Rn) in groundwater is a potential source of internal radiation exposure through
ingestion, particularly in regions where groundwater constitutes a major source of drinking
water. This study presents an assessment of 222Rn concentrations, radiological risks, and
measurement uncertainties in groundwater within Kubwa, Abuja, Nigeria, using liquid
scintillation counting. Thirty groundwater samples collected during the peak dry season were
analysed using a calibrated Tri-Carb 1000 TR liquid scintillation analyser, with corrections for
radioactive decay and partitioning effects. The 222Rn concentrations ranged from below the
detection limit to 2.30 Bq L⁻¹, with a mean of 0.29 ± 0.43 Bq L⁻¹. Estimated annual effective
doses were of the order of 10⁻³ mSv y⁻¹, well below the recommended reference level of 0.1
mSv y⁻¹. Expanded relative uncertainties (k = 2) ranged from approximately 6% for higheractivity samples to over 20% for samples near the detection limit. The results indicate a very
low radiological risk from 222Rn ingestion through groundwater and provide baseline data for
the study area. The findings also demonstrate the importance of considering detection limits
and measurement uncertainty in environmental radioactivity assessments.
This study investigates the concentration of Rn-222 in domestic water sources within Nasarawa metropolis, Nasarawa State, Nigeria. With the aim of accessing the potential health concerns related to radon accumulation. A total of thirty water samples comprising ten each from wells, boreholes, and streams were collected and analyzed using a liquid scintillation counter (Tri-Carb LSA 1000). Key parameters evaluated include Rn-222 activity concentration, annual effective dose from ingestion and inhalation, dose contributions to the stomach and lungs, and the excess lifetime cancer risk. Measured Rn-222 levels ranged from 0.06 to 18.50 counts per minute (cpm), with a background radiation count of 63.83 cpm attributed to environmental and non-sample sources. Radon activity concentrations spanned from 3.14 × 100 to 1.15 × 103 Bq/L, with an average of 4.17 × 101 Bq/L which substantially exceed the World Health Organization (WHO) recommended safety threshold of 100 Bq/L for drinking water. The mean annual effective dose from ingestion (3.05 × 10⁻³ mSv/y) remained below the International Commission on Radiological Protection (ICRP) public exposure limit of 1 mSv/y. However, the mean dose to the stomach was 3.65 × 10⁻⁴ mSv/y, indicating minor but quantifiable internal exposure. Notably, the average annual effective dose from inhalation was 18.4 mSv/y, significantly surpassing the ICRP guideline, thus raising potential health concerns, particularly in enclosed, poorly ventilated settings where radon may accumulate. The study therefore recommends continuous monitoring of domestic water sources and improved ventilation practices to minimize radon-related health risks.
Ahmad A. Sule, Ubaidullah Ahmad, Abdulkareem M. Hamza· Journal of Basics and Applie...· 0 citations
This study presents an accurate assessment of natural radioactivity levels of
226
Ra,
232
Th, and
40
K in 49 groundwater samples collected from the Tuban Delta in Yemen. Gamma ray spectroscopy was employed to quantify the radioactivity concentrations in the analyzed samples. In addition to radionuclide assessment, heavy metal concentrations were also measured. The results revealed average activity concentrations ranging from 0.83 to 6.5 Bq/L for
226
Ra, 1.2 to 3.7 Bq/L for
232
Th, and 110 to 172.3 Bq/L for
40
K. To evaluate potential health risks, effective doses were calculated based on measured radionuclide concentrations and typical water consumption patterns, yielding ranges of 0.3–1.29 mSv/year for infants, 0.04–2.20 mSv/year for children, and 0.02–1.34 mSv/year for adults. Pearson's correlation analysis revealed strong positive relationships among major ions (Ca
2+
, Mg
2+
, Na
+
) and natural radionuclides (
226
Ra,
232
Th), indicating geogenic influences on groundwater chemistry. Principal Component Analysis identified two main components explaining 83.7% of the variability, highlighting mineral dissolution and geochemical processes as key factors controlling water quality and radionuclide distribution in the Tuban Delta.
Emran Eisa Saleh, Dua'a Anis Taya, W. Abdurabu et al.· CLEAN - Soil, Air, Water· 0 citations
This study assessed the radiological hazard associated with sediment and silt samples collected from the Nile River. The results consistently demonstrated low levels of natural radioactivity. Calculated dose parameters were found to be well within international safety limits. The average outdoor annual effective dose equivalent (AEDEout) was 50 µSv/y for sediments and 60 µSv/y for silt. Similarly, the average indoor AEDE (AEDEin) values were 280 and 350 µSv/y, respectively, remaining significantly below the worldwide limit of 450 µSv/y. Long-term risk assessment further supported these findings, with the annual gonadal dose equivalent (AGDE) averaging 0.28 mSv/y for sediments and 0.36 mSv/y for silt. Finally, the calculated excess lifetime cancer risk (ELCR) remained low, at 1.15 × 10-3 for sediments and 1.44 × 10-3 for silt. The average radon concentrations in soil were 7.17 Bq/m3 for sediment and 5.65 Bq/m3 for silt. In conclusion, all measured activity concentrations and derived radiological risk factors confirm that the Nile River sediment and silt samples pose no significant radiological hazard to the public.
S. Fares, A. H. Korna, B. Alshahrani et al.· Isotopes in environmental an...· 0 citations
This study aimed to measure radon concentration in Djiri River water and to evaluate the associated equivalent doses, effective doses, and lifetime cancer mortality risks for the population of Brazzaville, Republic of Congo. Radon concentration was measured in 29 water samples collected from the Djiri River using an AlphaGUARD PQ2000 PRO radon detector. Polyethylene terephthalate (PET) bottles were evaluated for sample storage in order to estimate radon losses during storage. To enable a direct comparison with the National Research Council (1999) reference values, the estimated cancer mortality risks were normalized to the same reference radon concentration. Measured radon concentrations ranged from 0.23 to 0.73 Bq/L, with a mean value of 0.425±0.12 Bq/L (equivalent to 425±120 Bq/m³). These concentrations are low and indicate that radiation exposure through drinking water ingestion is minimal under the investigated conditions. The estimated annual effective doses from water ingestion were 5.37×10⁻6 mSv/year for infants, 4.45×10⁻3 mSv/year for 1-year-old children, 2.03×10⁻3 mSv/year for 5-year-old children, 1.18×10⁻3 mSv/year for 10-year-old children, 4.38×10⁻6 mSv/year for 15-year-old children, and 4.02×10⁻3 mSv/year for adults. All estimated doses remained well below the World Health Organization guideline value of 0.1 mSv/year for drinking water. The estimated lifetime cancer mortality risks for males, females, and the total population were 6.35×10⁻7, 9.45×10⁻7, and 7.68×10⁻7, respectively. After normalization to the same radon concentration, these estimates were consistent with the projections reported by the National Research Council (1999). Although the estimated doses and risks are very low and do not indicate a significant radiological health concern, the results support periodic monitoring of radon in the Djiri River as part of routine environmental and public health surveillance.
Guy Romuald Mossa Efouka, J. Bazoma, R. M. Moubakou Diahou et al.· Carpathian Journal of Earth...· 0 citations
This study assessed the natural radioactivity levels and associated radiological health risks in groundwater sources (boreholes and hand-dug wells) supplying residents of Ijebu-Igbo, Ogun State, Nigeria, where the population relies almost entirely on these sources for domestic water in the absence of a comprehensive municipal treatment scheme. Twenty-five (25) water samples were purposively collected from five sampling locations in each of five residential sections of the town (Atikori, Ojowo, Oke-Agbo, Oke-Alafia and Oke-Sopen), sealed in Marinelli beakers, and stored for forty days to attain secular equilibrium between parent and daughter radionuclides prior to counting. The activity concentrations of Uranium-238 (²³⁸U), Thorium-232 (²³²Th) and Potassium-40 (⁴⁰K) were determined by gamma-ray spectrometry using a High-Purity Germanium (HPGe) detector coupled to an 8192-channel multichannel analyser at the Nigerian Nuclear Regulatory Authority (NNRA) environmental laboratory, University of Ibadan. Radiological hazard indices – radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), absorbed dose rate (D), annual effective dose (AED) and excess lifetime cancer mortality risk (ELCMR) – were computed from the measured activities. Results showed mean activity concentrations of 53.60 ± 7.83 Bq/L for ²³⁸U, 4.81 ± 0.29 Bq/L for ²³²Th and 200.49 ± 10.19 Bq/L for ⁴⁰K. The mean Raeq (75.92 Bq/L), Hex (0.20) and Hin (0.34) were all below the reference limits of the World Health Organization (WHO), International Commission on Radiological Protection (ICRP) and International Atomic Energy Agency (IAEA). However, the mean AED of 1.30, 1.74 and 3.36 mSv/y for infants, adolescents and adults, respectively, exceeded the WHO reference level of 0.1 mSv/y, and one sampling point in Oke-Alafia recorded an anomalously high ²³⁸U concentration of 873.30 ± 121.87 Bq/L. The study concludes that groundwater in Ijebu-Igbo is largely radiologically safe for consumption, with the exception of the identified hotspot in Oke-Alafia. It is recommended that the affected borehole be investigated further and remediated, that residents of the affected area undergo periodic medical screening, and that routine radiometric monitoring of groundwater sources be instituted across the study area.
S. G. Ogunobi, K. A. Ogunjobi, G. O. Olanrewaju et al.· International journal of sci...· 0 citations
Groundwater serves as a primary source of domestic water in many urban areas across developing regions, yet naturally occurring radionuclides like Radon-222 can dissolve into aquifer systems and present health risks depending on subsurface geological conditions. This study aimed to statistically evaluate the concentration, spatial distribution, and lithological dependencies of Rn in groundwater across the distinct basement complex formations of Gusau metropolis. A total of 60 groundwater samples (boreholes and hand-dug wells) were collected across seven geological units using a stratified random sampling strategy. Radioactivity levels were analyzed using a Tri-Carb-LSA1000 Liquid Scintillation Counter (LSC) equipped for high-precision analysis after achieving radioactive equilibrium. Data were evaluated using descriptive statistics, frequency distribution modeling, one-way Analysis of Variance (ANOVA), and post-hoc Tukey HSD tests. The overall arithmetic mean concentration of Rn was found to be 26.37 ± 1.14 Bq/L (range: 11.03 - 59.99 Bq/L), with 55% of all samples clustering within the 20 - 30 Bq/L modal range. All measured values complied with the World Health Organization (WHO) reference guideline of 100 Bq/L, though 98.3% exceeded the USEPA maximum contaminant level of 11 Bq/L. Statistically, the data exhibited a positive skewness (1.398) and leptokurtic kurtosis (3.289), indicating localized high-concentration outliers. One-way ANOVA confirmed significant lithological influence on radon concentration (F = 3.066, p = 0.0119 < 0.05). Post-hoc analysis revealed that this statistical variation was primarily driven by a significant difference between the Migmatite (GS4) and Mica Schist (GS7) formations (p = 0.0466). These findings demonstrate that groundwater radon concentrations in Gusau metropolis are inherently controlled by local subsurface lithology. The highly sheared, foliated matrix of the Mica Schist optimizes alpha recoil and elevates radon emanation, whereas dense, recrystallized Migmatite segregations restrict fluid-rock interactions. The results provide essential baseline data for environmental monitoring and suggest that future public health water management strategies in the region should account for localized geological "hotspots" rather than assuming uniform regional risk.
A. Saidu, Abdulhakeem Umar, A. Umar et al.· UMYU Scientifica· 0 citations
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