Quantifying dissolved radon in drinking water using an augmented method

Quantifying dissolved radon in drinking water using an augmented method | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Quantifying dissolved radon in drinking water using an augmented method Maine K Wau, Henao Willie, David Kolkoma, Felix Beslin Pereira, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9145612/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Radioisotopes in drinking water raise several serious concerns for human health and environment. Surface and underground sources of water contain natural radionuclides in varying levels depending on the geology of the region on earth and their origin. Primordial radionuclide 226 Ra leaches from the geographical bodies and releases its gaseous progeny radon ( 222 Rn) into ground water in contact with. Radon in water also originates from dissolution of airborne radon into water and other higher radon bearing water in-flows in the catchment area. Aquatic organism intake radionuclides, which may lead to bioaccumulation, genetic mutations, and reproductive issues in them. It is a well-accepted fact that inhalation of indoor radon and its progeny have significant lung cancer risk for human beings. Ingesting radon-contaminated water may contribute to the development of carcinoma in internal organs, particularly within the gastrointestinal tract. Tap water and shower usage are among the primary sources of indoor radon exposure, as they release radon directly into the household air. Assessing dissolved radon in water is essential for evaluating potential health risks and ensuring environmental safety. We report the results of active measurements conducted using the Rad8 Radon Detector to quantify radon levels in drinking water samples collected from 53 locations in the city of Lae in Papua New Guinea. The method adopted is nascent in its method. The results show that the dissolved radon concentration varies from 3 ± 1 to 44 ± 5 Bq l − 1 with an average 24 ± 7 Bq l − 1 . Dissolved radon concentrations in majority of samples were between 18 and 32 Bq l − 1 . Estimated annual effective dose of radiation from radon exposure due to dissolved radon in water was 0.15 ± 0.04 µSv y − 1 which poses no health risk upon consumption. Dissolved radon water RAD8 ingestion dose inhalation dose effective annual dose Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Radon is a naturally occurring radioactive gas that can dissolve in groundwater from the neighbouring geophysical and geochemical activities. Underground water contains natural radionuclides in various concentrations depending on their origin. Radon and its progeny contribute more than half of the total radiation dose to the human being and also the second major cause of lung cancer after cigarette smoking (Belete & Anteneh, 2021; Onoja et al., 2024). Radon is released as a result of natural decay of 226 Ra in the rocks and soil and dissolves predominantly in water. (Moreno, 2014). Radon dissolves well in water than other noble gases. The solubility of the radon decreases with temperature. (Rani et al,.2021; Jin Chen, 2019.). Ostwald coefficient which represents the solubility of a gas, is 0.25 at 20 o C and has inverse relation with increase in temperature. Solubility of radon has an inverse relation with salinity, but minimal impact on pH of water (Yong-jun, 2019). Radon in drinking water can cause radiation expose to the people through both ingestion and inhalation. Inhalation of radon causes lung cancer and he ingestion though food can affect intestinal pathways. Long-term exposure to radon is linked to increased risks of lung and stomach cancer, especially where there are high natural radon levels persists. 226 Ra is one of the abundant naturally occurring radioactive materials in rocks, stones, and soils, in the Earth’s crust (Shahrokhi A, 2014). Indoor radon generated in the geological materials mainly migrates and enters dwellings through cracks in walls, basements, and foundations. Tap water used in the kitchen or shower can be another source of radon in homes (WHO,2009). A worldwide estimation by World Health Organisation found that about 1-7% of all lung cancer deaths emerged from high level concentration of dissolved radon in drinking water and about 10-15% of total indoor exposures are from escaped radon, from tape waters and showers (Onoja et al., 2024). Papua New Guinea belongs to the seismic region known as the ‘ring of fire’ with a couple of active volcanos in the area. Even though a detailed baseline data on the radionuclide content in the surface soil or geological materials in the country is not available there are observations of elevated levels of radionuclides in certain region (Kolkoma, 2023). Measuring dissolved radon is important to determine if water sources are safe for consumption, especially in regions near mines, uranium-rich rocks, or in industrial zones. Radon levels can throw light into the underlying geological activity and contamination from sources like mining waste, fossil fuel combustion and the like in the region. Lae is the second largest city in Papua New Guinea and has numerous industries of different kinds. To date, there are no documented studies on radon in water from any region of Papua New Guinea. However, a few investigations have explored radon presence in indoor environments and the atmosphere (Jojo, 2019; Felix, 2024). Therefore, the present study focuses on measuring radon concentration in ground water collected from various sources in the city of Lae, to investigate how radiologically safe are the drinking water in the region. Based on the results of radon concentrations in water, annual effective dose of radiation from radon exposure for different age groups and an estimate of ingestion dose risks have also been determined. Experimental methods a) Description of the locale: City of Lae, widely accepted as Papua New Guinea’s industrial powerhouse, is the capital of Morobe Province (Fig. 1 ). Lae is strategically located near the Markham River delta, serves as the country’s largest cargo port, and a vital gateway to the densely populated highland region. The city of Lae is the home to major industrial sectors including manufacturing, distribution, fisheries, mining, and agriculture. According to the latest census (2021) the population is about 150,000 with a growth rate of 3.6% per annum. Lae experiences a tropical rainforest climate and is one among the wettest cities on the planet, receiving significant rainfall even during dry months. The average temperature of the city is about 24°C and relative humidity of about 85%. b) Sample collection: For collecting drinking water sample EPA protocols were followed (EPA, 2016 ). Representative natural ground water samples were collected following the EPA protocols from 53 locations in the city of Lae located close to the equator. (Latitude: 6 o 43’ S and Longitude:146 o 59’ E; as per https://latitude.to ). The study used a methodical sampling strategy to collect water samples from wells, boreholes, and surface water bodies in different locations. during the months of May to September 2025 from the surrounding region of the Papua New Guinea University of Technology (PNGUoT) with an approximate sampling area of 24 km 2 . Fresh water samples were collected in leak-tight bottles made up of low-permeability material having a volume of 1000 ml. Sufficient precautions were taken during sampling to minimize aeration and prevent loss of dissolved radon in water sample. The sample bottle was sealed airtight, maintained with minimal agitation and without any variation in ambient temperature and pressure. Measurements were carried out within 3 h of sample collection to minimize the loss of radon due to the radioactive decay process. c) Instrumentation: RAD8 manufactured by Durridge, USA was designed for continuous real-time radon detection and spectral analysis. RAD8 is a highly versatile comprehensive radon and thoron measurement system. We used an improvised probe to measure radon in water samples. The probe consists of a semi-permeable helical polyethylene tube of wall thickness 10 − 3 m. The helical tube was placed in the water sample to allow radon gas diffuse into it (Fig. 2 ). The tube was connected in closed loop with the RAD8. Before the measurements RAD8 was purged for 8 minutes to remove any left-out radon and progeny inside the detector. The instrument was connected in closed-loop configuration with the helical tube completely immersed in the water sample and the measurement was carried out with a measurement cycle of minimum 24 hrs. During this period of time the radon concentration was found to attain an equilibrium conentration. The radon concentration in the air column of the tube was used to determine the original dissolved radon concentration in water at the equilibrium condition. Radon ( 222 Rn) and its progeny decay inside the RAD8 chamber, emitting alpha particles which are electrostatically collected on the silicon detector, producing an electrical pulse and are processed to determine radon concentration in the air loop. Knowing the equilibrium partition coefficient and measured radon activity in the air, the original radon concentration in the water sample was determined. RAD8 makes radon measurements in every 30 minutes. Radon in water diffuses into the tube until it reaches an equilibrium with radon in water. This can be observed from the growth curve of radon in the RAD8. Dry stick, a tubular desiccant system, was used inside the recursive loop to allow only dry air to measure the radon concentration. The detector makes use of the alpha-spectrometry method for the determination radon in the air. Before each measurement using RAD8, purging of the device was carried out to remove undesired moisture and humidity from the measurement chamber. a) Mathematical formulations Different techniques are used to measure the amount of radon present in water samples. In the present study the plastic tube contains an air column that is continuously circulated through a radon detector and back into the tube. Radon diffuses from the surrounding water into the air column inside the tube. As the air circulates, the detector measures radon concentration in real time. Over the time, the radon concentration stabilizes, allowing for accurate calculation of the radon level in the water using the partition coefficient between air and water. The sealed loop reduces radon loss and external contamination. This method enables real-time monitoring and trend analysis without repeated sampling. The radon buildup in the system, can be written as: \(\:\frac{dC\left(t\right)}{dt}\) = E - λ C(t) (1) Where, C(t) is the radon concentration in air at time, t E – is the entry rate of radon from water to the air column and 𝜆 = decay constant of radon (≈ 2.1 × 10⁻⁶ s⁻¹) This equation assumes a constant radon entry rate and accounts for radioactive decay. Being a closed aeration system, no decay correction is needed. When there is a constant build up radon in the tube, ( \(\:\frac{dC\left(t\right)}{dt}\) = 0), we have, E = λ C(t). Once radon concentration in air at steady state is determined, we can use the Partition Coefficient, K to convert the radon concentration in air to that in water, using the relation: C water = K \(\:\times\:\) C air (2) Partition Coefficient, K is a temperature dependent constant and, in this study, we adopted the value of K ≈ 0.25 (Schwarzenbach, 2005). Therefore, the concentration in water was estimated from the radon concentration in air. Annual Effective Dose The pathways of radon gas to human body are through ingestion and through inhalation. Ingestion of radon through consumption of water and inhalation of radon gas released from water to indoor air contribute radiation doses. Therefore, the annual effective dose (AED) for ingestion and inhalation are determined (UNSCEAR, 2000). The annual effective dose due to ingestion of radon was estimated using the dose coefficient Factor (DCF) of 3.5 nSv per Becquerel and average annual intake of water (RAI = 1095 l y − 1 ). For inhalation dose estimation, it was assumed that the ratio of radon to tap water is 10 − 4 . Average indoor occupancy (AO) of 7000 hours per year and the equilibrium factor (EF) between radon and progeny of 0.4 was assumed. Radon inhalation dose conversion factor (DCF) used was 9nSv Bq − 1 m − 3 h − 1 . An annual effective dose of 2.5 µSv from inhalation of radon was estimated based on a tap water radon concentration of 1000 Bq/m³. (UNSCEAR,2000; Somashekar and Ravikumar, 2010 ; Inaam, 2015). AED(Ingestion) = CRn(Water) \(\:\times\:\) RAI \(\:\:\times\:\) DCF(Ingestion) (3) AED (Inhalation) = CRn(Water) \(\:\times\:\) 10 − 4 \(\:\times\:\) AO(Indoor) \(\:\:\times\:\) EF \(\:\times\:\) DCF(Inhalation) (4) Therefore, the contribution of total annual effective dose from the dissolved radon in water is: AED(Total) = AED(Ingestion) + AED (Inhalation) (5) The above quantity represents the annual effective dose to the human beings owing to dissolved radon in water alone. Results and discussion Analysis of 53 water samples using RAD8 radon detector which make use of alpha spectrometry by measuring the parent radionuclides 218 Po and 214 Po in the decay chain of 222 Rn give the results presented in the Table 1 . Table 1 Statistical distribution of dissolved radon in water and annual effective dose Sample size = 53 Rn concentration (Bq l − 1 ) Annual Effective Dose (mSv y − 1 ) In air In water Ingestion Inhalation Total Minimum 36 ± 5 3 ± 1 0.01 0.01 0.02 Maximum 178 ± 16 44 ± 5 0.17 0.11 0.28 Average 98 ± 25 24 ± 7 0.09 ± 0.03 0.06 ± 0.02 0.15 ± 0.04 The average radon concentration in water samples was found to be 24 ± 7 Bq l − 1 . The average annual effective doses from ingestion and inhalation of radon were 0.09 ± 0.04 mSv and 0.06 ± 0.02 mSv respectively and the total annual effective dose was found to be 0.15 ± 0.04 mSv. It may be noted that the annual ingestion dose and the inhalation dose evaluated are merely the doses resulting from the consumption water with dissolved radon and release of radon from water being used in the dwellings. Based on a good rule of thumb that 10 4 Bq l − 1 in water can contribute about 1 Bq l − 1 to indoor radon concentration, the contribution of dissolved radon towards the indoor radon is negligibly small for the region of study. The obtained results showed that the annual effective dose due to ingestion of the water was below the reference level of 0.1 mSv y –1 in most of the samples and hence do not cause any health concern from the radiation dose received from water in the study regions (WHO, 2017 ). Analysis of data In general, the distribution of dissolved radon concentrations in groundwater is limited to a range of 18 to 32 Bq l − 1 for the region as seen in the Fig. 3 . The data on radon shows a moderate positive skewness of 0.8 indicating the data clusters slightly towards lower values with a few relatively large values stretching the distribution. The kurtosis 2.9 shows somewhat a normal distribution of data. Furthermore, Q-Q plot of the data points (Fig. 4 ) closely follows a straight diagonal line, indicating an almost normal distribution of the total annual effective dose resulting from the dissolved radon in the samples analysed. The data points obtained in the experiment are closely follow the diagonal line suggest that the distribution of the total annual effective dose values is very similar to a theoretical normal distribution. This indicates that the sample data does not deviate significantly from normality. From the plot of the data no major curvature, clustering, or systematic departures from the line are observed which implies there is no evidence of skewness or heavy tails in the dataset. The normal distribution suggests that the variation in annual effective dose from dissolved radon across samples is random and evenly spread, without extreme outliers or irregular patterns. The finding implies that most individuals in the sampled population receive doses around the mean value, with fewer individuals at the extremes. This supports the reliability of using average dose values for public health risk assessments. The World Health Organization (WHO) and the European Commission (EU) set the guidance level to 100 Bql − 1 (EU, 2001 ; WHO, 2017 ). The WHO has recommended a reference dose level (RDL) of 0.1 mSv due to the annual intake of drinking water. Radon concentrations in the water samples in the present study are much lower than the reference level of 100 Bq∙l − 1 . UNSCEAR suggested a value of radon concentration in water for human consumption between 4 and 40 Bq l − 1 (UNSCEAR, 2008 ). Our results agree well with many other research conducted in different parts of the region. The results of radon measurements in shallow-well water from Phichit subdistrict in the Songkhla province, in Thailand ranged from 0.18 ± 0.07 to 98.1 ± 5.92 Bq l − 1 with a mean value of 16.7 ± 2.33 Bq l − 1 . The range of annual effective doses from ingestion and inhalation of radon were 0.03–17.66 and 0.45–245.25 µSv y − 1 , respectively. The estimated total annual effective dose due to ingestion and inhalation ranged from 0.48 to 262.91 µSv y −1v (Charoensri, 2014). In another investigation held in India, radon concentrations in ground water samples collected from 16 hand pumps in the Varahi river basins, in the Karnataka State, ranged between 0.2 ± 0.4 and 10.1 ± 1.7 Bq l − 1 with an average of 2.07 ± 0.84 Bq l − 1 (Somashekar, 2010 ). Conclusions Radon concentrations measured in 53 groundwater samples collected from different locations of the city of Lae in Papua New Guinea were mostly in a range of 18 to 32 Bq l − 1 with an average 24 ± 7 Bq l − 1 . Near normal distribution of these values implies that the majority of samples cluster around the mean, with predictable probabilities of higher or lower concentrations. The Q-Q plot’s confirmation of normality strengthens confidence in these dose estimates, as parametric methods used to calculate averages and confidence intervals are statistically justified. Except at a few locations, the effective dose results were lower than internationally accepted reference values. The normal distribution confirmed by the Q-Q plot provides statistical assurance that these exceedances are isolated rather than systematic, reinforcing the conclusion that the majority of the population is not at risk. This strong statistical evidence confirms that the dataset is well-behaved, with no significant skewness or heavy tails. The distribution of data allows for reliable risk modelling and supports regulatory compliance assessments. With most samples showing effective doses below safety thresholds, groundwater in the investigated area poses no significant radiological health risk to the population, except for a few localized exceedances that warrant further monitoring. Declarations Conflicts of Interest The authors declare no conflicts of interest regarding the publication of this paper. Author Contribution PJ: Conceptualisation, manuscript preparation and supervisionMW: Design of experiment HW: Sample acquisition and analysisFP: Critical revision of manuscriptDK: Interpretation of results Acknowledgments The authors thankfully acknowledge the financial assistance for the study from the Postgraduate Studies, Research and Innovation Committee, Papua New Guinea University of Technology. References Asadi Mohammad Abadi, A., Rahimi, M. and Jabbari-Koopaei, L. (2021). Measurement of dissolved radon concentration in groundwater samples of Shahre Babak city and estimation of annual effective absorbed dose. Journal of Radiation Safety and Measurement , 10 (3), 31-38. doi: 10.22052/9.3.31. Belete, G. D., & Anteneh, Y. A. (2021). General Overview of radon Studies in Health hazard Perspectives. Journal of Oncology , 2021 , 1–7. https://doi.org/10.1155/2021/6659795 Charoensri A., Siriboonprapob S. and Sastri N. (2015) Analysis of radon in shallow-well water: a case study at Phichit subdistrict in Songkhla province, Thailand. Journal of Physics: Conference Series 611 (2015) 012025. https://doi:10.1088/1742-6596/611/1/012025 Chen, J. (2019). A DISCUSSION ON ISSUES WITH RADON IN DRINKING WATER. Radiation Protection Dosimetry . https://doi.org/10.1093/rpd/ncz035 EPA (2016) Quick Guide To Drinking Water Sample Collection, United States Environmental Protection Agency, 2 nd Ed. EU (2001) EU Recommendation on the protection of the public against exposure to radon in drinking water supplies. Off. J. Eur. 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Epub November 13, 2013. doi:10.1016/j.jenvrad.2013.10.021 Onoja, E. D., Onyekachi, G. A., Ejila, A. O., Okoh, P., & Jack, Z. K. (2024). Measurement of Radon Gas Concentration in Sources of Drinking Water in Makurdi, Benue State, Nigeria Using Radon Detector (RAD-7). UMYU Scientifica , 3 (3), 322–332. https://doi.org/10.56919/usci.2433.034 Rani, S., Kansal, S., Singla, A. K., & Mehra, R. (2021). Radiological risk assessment to the public due to the presence of radon in water of Barnala district, Punjab, India. Environmental Geochemistry and Health , 43 (12), 5011–5024. https://doi.org/10.1007/s10653-021-01012-y Schwarzenbach R.P., Gschwend P.M., Imboden, D. M. (2005) Environmental Organic Chemistry, 2nd Ed., Wiley and Sons, ISBN: 978-0-471-64964-9. Shahrokhi A, Szeiler G, Rahimi H, Kovács T (2014) Investigation of natural and anthropogenic radio nuclides distribution in arable land soil of south eastern European countries. IJSER Research. 5(11):445-449. Somashekar R. K. and Ravikumar P (2010) Radon concentration in groundwater of Varahi and Markandeya River basins, Karnataka State, India. J Radioanal Nucl Chem 285:343–351. http://doi.org/10.1007/s10967-010-0573-x The World Health Organization. WHO handbook on indoor radon: a public health perspective. In Hajo Z, Ferid S (eds). Geneva; WHO Press. 2009. UNSCEAR 2000, United Nations Scientific Committee on the Effects of Atomic Radiation 2000 Sources and Effects of Ionizing Radiation vol. 1 (New York: United Nations) UNSCEAR 2008 Sources and Effects of Ionizing Radiation 2008 (New York: UNSCEAR) WHO (2017) WHO Guidelines for Drinking-Water Quality, the Fourth Edition Incorporating the First Addenda. World Health Organization, Geneva, Switzerland. Yong-jun Ye, Xiang-qian Xia, Xin-tao Dai, Chun-hua Huang & Qian Guo (2019) Effects of temperature, salinity, and pH on 222 Rn solubility in water. Journal of Radioanalytical and Nuclear Chemistry. 320, 369–375. Additional Declarations No competing interests reported. Supplementary Files AnnexureA.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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2","display":"","copyAsset":false,"role":"figure","size":253280,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of the experimental set up for the measurement using RAD8\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9145612/v1/6b09da0076f065fdc7ea6d7c.png"},{"id":105566229,"identity":"1615a182-2dcd-43c1-b567-41b75924bd23","added_by":"auto","created_at":"2026-03-27 12:55:48","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":65842,"visible":true,"origin":"","legend":"\u003cp\u003eScatter diagram of the dissolved radon concentrations in water samples\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9145612/v1/4a045bb6009c674874fbed78.png"},{"id":105499746,"identity":"99d8bba1-3d07-42e4-aec0-4a2250e8bf16","added_by":"auto","created_at":"2026-03-26 17:15:19","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":115774,"visible":true,"origin":"","legend":"\u003cp\u003eThe Quantile-Quantile plot of the total dose data\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-9145612/v1/717633dbc505535df983fca2.png"},{"id":105570244,"identity":"4383f5de-3b6f-47ed-ab43-0e93cbe36645","added_by":"auto","created_at":"2026-03-27 13:15:43","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1106220,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9145612/v1/142ba5cb-1073-4e1b-8487-06b8ec798de9.pdf"},{"id":105566698,"identity":"c9d3fb8c-9407-4e52-aecc-718561a7f3ec","added_by":"auto","created_at":"2026-03-27 12:57:01","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":20557,"visible":true,"origin":"","legend":"","description":"","filename":"AnnexureA.docx","url":"https://assets-eu.researchsquare.com/files/rs-9145612/v1/472007112a5a74ec49ae72cd.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Quantifying dissolved radon in drinking water using an augmented method","fulltext":[{"header":"Introduction","content":"\u003cp\u003eRadon is a naturally occurring radioactive gas that can dissolve in groundwater from the neighbouring geophysical and geochemical activities. Underground water contains natural radionuclides in various concentrations depending on their origin. Radon and its progeny contribute more than half of the total radiation dose to the human being and also the second major cause of lung cancer after cigarette smoking (Belete \u0026amp; Anteneh, 2021; Onoja et al., 2024). Radon is released as a result of natural decay of \u003csup\u003e226\u003c/sup\u003eRa in the rocks and soil and dissolves predominantly in water. (Moreno, 2014). Radon dissolves well in water than other noble gases. The solubility of the radon decreases with temperature. (Rani et al,.2021; Jin Chen, 2019.). Ostwald coefficient which represents the solubility of a gas, is 0.25 at 20\u003csup\u003eo\u003c/sup\u003eC and has inverse relation with increase in temperature. \u0026nbsp;Solubility of radon has an inverse relation with salinity, but minimal impact on pH of water (Yong-jun, 2019). \u0026nbsp;Radon in drinking water can cause radiation expose to the people through both ingestion and inhalation. Inhalation of radon causes lung cancer and he ingestion though food can affect intestinal pathways. Long-term exposure to radon is linked to increased risks of lung and stomach cancer, especially where there are high natural radon levels persists. \u003csup\u003e226\u003c/sup\u003eRa is one of the abundant naturally occurring radioactive materials in rocks, stones, and soils, in the Earth\u0026rsquo;s crust (Shahrokhi A, 2014). Indoor radon generated in the geological materials mainly migrates and enters dwellings through cracks in walls, basements, and foundations. Tap water used in the kitchen or shower can be another source of radon in homes (WHO,2009). A worldwide estimation by World Health Organisation found that about 1-7% of all lung cancer deaths emerged from high level concentration of dissolved radon in drinking water and about 10-15% of total indoor exposures are from escaped radon, from tape waters and showers (Onoja et al., 2024).\u003c/p\u003e\n\u003cp\u003ePapua New Guinea belongs to the seismic region known as the \u0026lsquo;ring of fire\u0026rsquo; with a couple of active volcanos in the area. Even though a detailed baseline data on the radionuclide content in the surface soil or geological materials in the country is not available there are observations of elevated levels of radionuclides in certain region (Kolkoma, 2023). Measuring dissolved radon is important to determine if water sources are safe for consumption, especially in regions near mines, uranium-rich rocks, or in industrial zones. Radon levels can throw light into the underlying geological activity and contamination from sources like mining waste, fossil fuel combustion and the like in the region. Lae is the second largest city in Papua New Guinea and has numerous industries of different kinds. To date, there are no documented studies on radon in water from any region of Papua New Guinea. However, a few investigations have explored radon presence in indoor environments and the atmosphere (Jojo, 2019; Felix, 2024). Therefore, the present study focuses on measuring radon concentration in ground water collected from various sources in the city of Lae, to investigate how radiologically safe are the drinking water in the region. \u0026nbsp;Based on the results of radon concentrations in water, annual effective dose of radiation from radon exposure for different age groups and an estimate of ingestion dose risks have also been determined.\u0026nbsp;\u003c/p\u003e"},{"header":"Experimental methods","content":"\u003ch2\u003ea) Description of the locale: \u0026nbsp;\u003c/h2\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eCity of Lae, widely accepted as Papua New Guinea\u0026rsquo;s industrial powerhouse, is the capital of Morobe Province (Fig. \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Lae is strategically located near the Markham River delta, serves as the country\u0026rsquo;s largest cargo port, and a vital gateway to the densely populated highland region. The city of Lae is the home to major industrial sectors including manufacturing, distribution, fisheries, mining, and agriculture. According to the latest census (2021) the population is about 150,000 with a growth rate of 3.6% per annum. Lae experiences a tropical rainforest climate and is one among the wettest cities on the planet, receiving significant rainfall even during dry months. The average temperature of the city is about 24\u0026deg;C and relative humidity of about 85%.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eb) Sample collection:\u003c/h2\u003e\n \u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eFor collecting drinking water sample EPA protocols were followed (EPA, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Representative natural ground water samples were collected following the EPA protocols from 53 locations in the city of Lae located close to the equator. (Latitude: 6\u003csup\u003eo\u003c/sup\u003e43\u0026rsquo; S and Longitude:146\u003csup\u003eo\u003c/sup\u003e59\u0026rsquo; E; as per \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://latitude.to\u003c/span\u003e\u003c/span\u003e). The study used a methodical sampling strategy to collect water samples from wells, boreholes, and surface water bodies in different locations.\u003c/p\u003e\n \u003cp\u003eduring the months of May to September 2025 from the surrounding region of the Papua New Guinea University of Technology (PNGUoT) with an approximate sampling area of 24 km\u003csup\u003e2\u003c/sup\u003e. Fresh water samples were collected in leak-tight bottles made up of low-permeability material having a volume of 1000 ml. Sufficient precautions were taken during sampling to minimize aeration and prevent loss of dissolved radon in water sample. The sample bottle was sealed airtight, maintained with minimal agitation and without any variation in ambient temperature and pressure. Measurements were carried out within 3 h of sample collection to minimize the loss of radon due to the radioactive decay process.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003ch3\u003ec) Instrumentation:\u003c/h3\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eRAD8 manufactured by Durridge, USA was designed for continuous real-time radon detection and spectral analysis. RAD8 is a highly versatile comprehensive radon and thoron measurement system. We used an improvised probe to measure radon in water samples. The probe consists of a semi-permeable helical polyethylene tube of wall thickness 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e m. The helical tube was placed in the water sample to allow radon gas diffuse into it (Fig. \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The tube was connected in closed loop with the RAD8. Before the measurements RAD8 was purged for 8 minutes to remove any left-out radon and progeny inside the detector. The instrument was connected in closed-loop configuration with the helical tube completely immersed in the water sample and the measurement was carried out with a measurement cycle of minimum 24 hrs. During this period of time the radon concentration was found to attain an equilibrium conentration.\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003eThe radon concentration in the air column of the tube was used to determine the original dissolved radon concentration in water at the equilibrium condition. Radon (\u003csup\u003e222\u003c/sup\u003eRn) and its progeny decay inside the RAD8 chamber, emitting alpha particles which are electrostatically collected on the silicon detector, producing an electrical pulse and are processed to determine radon concentration in the air loop. Knowing the equilibrium partition coefficient and measured radon activity in the air, the original radon concentration in the water sample was determined.\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n \u003cp\u003eRAD8 makes radon measurements in every 30 minutes. Radon in water diffuses into the tube until it reaches an equilibrium with radon in water. This can be observed from the growth curve of radon in the RAD8. Dry stick, a tubular desiccant system, was used inside the recursive loop to allow only dry air to measure the radon concentration. The detector makes use of the alpha-spectrometry method for the determination radon in the air. Before each measurement using RAD8, purging of the device was carried out to remove undesired moisture and humidity from the measurement chamber.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003ea) Mathematical formulations\u003c/h3\u003e\n\u003cp\u003eDifferent techniques are used to measure the amount of radon present in water samples. In the present study the plastic tube contains an air column that is continuously circulated through a radon detector and back into the tube. Radon diffuses from the surrounding water into the air column inside the tube. As the air circulates, the detector measures radon concentration in real time. Over the time, the radon concentration stabilizes, allowing for accurate calculation of the radon level in the water using the partition coefficient between air and water. The sealed loop reduces radon loss and external contamination. This method enables real-time monitoring and trend analysis without repeated sampling.\u003c/p\u003e\n\u003cp\u003eThe radon buildup in the system, can be written as:\u003c/p\u003e\n\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u0026nbsp;\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{dC\\left(t\\right)}{dt}\\)\u003c/span\u003e\u0026nbsp;\u003c/span\u003e = E - \u0026lambda; C(t) (1)\u003c/p\u003e\n\u003cp\u003eWhere, C(t) is the radon concentration in air at time, t\u003c/p\u003e\n\u003cp\u003eE \u0026ndash; is the entry rate of radon from water to the air column and\u003c/p\u003e\n\u003cp\u003e𝜆 = decay constant of radon (\u0026asymp;\u0026thinsp;2.1 \u0026times; 10⁻⁶ s⁻\u0026sup1;)\u003c/p\u003e\n\u003cp\u003eThis equation assumes a constant radon entry rate and accounts for radioactive decay. Being a closed aeration system, no decay correction is needed. When there is a constant build up radon in the tube, (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{dC\\left(t\\right)}{dt}\\)\u003c/span\u003e\u003c/span\u003e = 0), we have, E\u0026thinsp;=\u0026thinsp;\u0026lambda; C(t).\u003c/p\u003e\n\u003cp\u003eOnce radon concentration in air at steady state is determined, we can use the Partition Coefficient, K to convert the radon concentration in air to that in water, using the relation:\u003c/p\u003e\n\u003cp\u003eC\u003csub\u003ewater\u003c/sub\u003e = K \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\times\\:\\)\u003c/span\u003e\u003c/span\u003e C\u003csub\u003eair\u003c/sub\u003e (2)\u003c/p\u003e\n\u003cp\u003ePartition Coefficient, K is a temperature dependent constant and, in this study, we adopted the value of K\u0026thinsp;\u0026asymp;\u0026thinsp;0.25 (Schwarzenbach, 2005). Therefore, the concentration in water was estimated from the radon concentration in air.\u003c/p\u003e\n\u003ch3\u003eAnnual Effective Dose\u003c/h3\u003e\n\u003cp\u003eThe pathways of radon gas to human body are through ingestion and through inhalation. Ingestion of radon through consumption of water and inhalation of radon gas released from water to indoor air contribute radiation doses. Therefore, the annual effective dose (AED) for ingestion and inhalation are determined (UNSCEAR, 2000). The annual effective dose due to ingestion of radon was estimated using the dose coefficient Factor (DCF) of 3.5 nSv per Becquerel and average annual intake of water (RAI\u0026thinsp;=\u0026thinsp;1095 l y\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). For inhalation dose estimation, it was assumed that the ratio of radon to tap water is 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e. Average indoor occupancy (AO) of 7000 hours per year and the equilibrium factor (EF) between radon and progeny of 0.4 was assumed. Radon inhalation dose conversion factor (DCF) used was 9nSv Bq\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. An annual effective dose of 2.5 \u0026micro;Sv from inhalation of radon was estimated based on a tap water radon concentration of 1000 Bq/m\u0026sup3;. (UNSCEAR,2000; Somashekar and Ravikumar, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Inaam, 2015).\u003c/p\u003e\n\u003cp\u003eAED(Ingestion)\u0026thinsp;=\u0026thinsp;CRn(Water) \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\times\\:\\)\u003c/span\u003e\u003c/span\u003e RAI\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\:\\times\\:\\)\u003c/span\u003e\u003c/span\u003e DCF(Ingestion) (3)\u003c/p\u003e\n\u003cp\u003eAED (Inhalation)\u0026thinsp;=\u0026thinsp;CRn(Water) \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\times\\:\\)\u003c/span\u003e\u003c/span\u003e 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\times\\:\\)\u003c/span\u003e\u003c/span\u003e AO(Indoor)\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\:\\times\\:\\)\u003c/span\u003e\u003c/span\u003e EF \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\times\\:\\)\u003c/span\u003e\u003c/span\u003e DCF(Inhalation) (4)\u003c/p\u003e\n\u003cp\u003eTherefore, the contribution of total annual effective dose from the dissolved radon in water is:\u003c/p\u003e\n\u003cp\u003eAED(Total)\u0026thinsp;=\u0026thinsp;AED(Ingestion)\u0026thinsp;+\u0026thinsp;AED (Inhalation) (5)\u003c/p\u003e\n\u003cp\u003eThe above quantity represents the annual effective dose to the human beings owing to dissolved radon in water alone.\u003c/p\u003e"},{"header":"Results and discussion","content":"\u003cp\u003eAnalysis of 53 water samples using RAD8 radon detector which make use of alpha spectrometry by measuring the parent radionuclides \u003csup\u003e218\u003c/sup\u003ePo and \u003csup\u003e214\u003c/sup\u003ePo in the decay chain of \u003csup\u003e222\u003c/sup\u003eRn give the results presented in the Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eStatistical distribution of dissolved radon in water and annual effective dose\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSample size\u0026thinsp;=\u0026thinsp;53\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eRn concentration\u003c/p\u003e \u003cp\u003e(Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003eAnnual Effective Dose\u003c/p\u003e \u003cp\u003e(mSv y\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIn air\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIn water\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eIngestion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eInhalation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMinimum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e36\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e3\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaximum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e178\u0026thinsp;\u0026plusmn;\u0026thinsp;16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e44\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.28\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e98\u0026thinsp;\u0026plusmn;\u0026thinsp;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e24\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe average radon concentration in water samples was found to be 24\u0026thinsp;\u0026plusmn;\u0026thinsp;7 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The average annual effective doses from ingestion and inhalation of radon were 0.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04 mSv and 0.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 mSv respectively and the total annual effective dose was found to be 0.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04 mSv. It may be noted that the annual ingestion dose and the inhalation dose evaluated are merely the doses resulting from the consumption water with dissolved radon and release of radon from water being used in the dwellings. Based on a good rule of thumb that 10\u003csup\u003e4\u003c/sup\u003e Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in water can contribute about 1 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to indoor radon concentration, the contribution of dissolved radon towards the indoor radon is negligibly small for the region of study. The obtained results showed that the annual effective dose due to ingestion of the water was below the reference level of 0.1 mSv y\u003csup\u003e\u0026ndash;1\u003c/sup\u003e in most of the samples and hence do not cause any health concern from the radiation dose received from water in the study regions (WHO, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eAnalysis of data\u003c/h2\u003e \u003cp\u003eIn general, the distribution of dissolved radon concentrations in groundwater is limited to a range of 18 to 32 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for the region as seen in the Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe data on radon shows a moderate positive skewness of 0.8 indicating the data clusters slightly towards lower values with a few relatively large values stretching the distribution. The kurtosis 2.9 shows somewhat a normal distribution of data. Furthermore, Q-Q plot of the data points (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) closely follows a straight diagonal line, indicating an almost normal distribution of the total annual effective dose resulting from the dissolved radon in the samples analysed. The data points obtained in the experiment are closely follow the diagonal line suggest that the distribution of the total annual effective dose values is very similar to a theoretical normal distribution. This indicates that the sample data does not deviate significantly from normality. From the plot of the data no major curvature, clustering, or systematic departures from the line are observed which implies there is no evidence of skewness or heavy tails in the dataset. The normal distribution suggests that the variation in annual effective dose from dissolved radon across samples is random and evenly spread, without extreme outliers or irregular patterns. The finding implies that most individuals in the sampled population receive doses around the mean value, with fewer individuals at the extremes. This supports the reliability of using average dose values for public health risk assessments.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe World Health Organization (WHO) and the European Commission (EU) set the guidance level to 100 Bql\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (EU, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; WHO, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). The WHO has recommended a reference dose level (RDL) of 0.1 mSv due to the annual intake of drinking water. Radon concentrations in the water samples in the present study are much lower than the reference level of 100 Bq∙l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. UNSCEAR suggested a value of radon concentration in water for human consumption between 4 and 40 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (UNSCEAR, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Our results agree well with many other research conducted in different parts of the region. The results of radon measurements in shallow-well water from Phichit subdistrict in the Songkhla province, in Thailand ranged from 0.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07 to 98.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.92 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with a mean value of 16.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.33 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The range of annual effective doses from ingestion and inhalation of radon were 0.03\u0026ndash;17.66 and 0.45\u0026ndash;245.25 \u0026micro;Sv y\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. The estimated total annual effective dose due to ingestion and inhalation ranged from 0.48 to 262.91 \u0026micro;Sv y\u003csup\u003e\u0026minus;1v\u003c/sup\u003e (Charoensri, 2014). In another investigation held in India, radon concentrations in ground water samples collected from 16 hand pumps in the Varahi river basins, in the Karnataka State, ranged between 0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4 and 10.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with an average of 2.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Somashekar, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2010\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eRadon concentrations measured in 53 groundwater samples collected from different locations of the city of Lae in Papua New Guinea were mostly in a range of 18 to 32 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with an average 24\u0026thinsp;\u0026plusmn;\u0026thinsp;7 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Near normal distribution of these values implies that the majority of samples cluster around the mean, with predictable probabilities of higher or lower concentrations. The Q-Q plot\u0026rsquo;s confirmation of normality strengthens confidence in these dose estimates, as parametric methods used to calculate averages and confidence intervals are statistically justified. Except at a few locations, the effective dose results were lower than internationally accepted reference values. The normal distribution confirmed by the Q-Q plot provides statistical assurance that these exceedances are isolated rather than systematic, reinforcing the conclusion that the majority of the population is not at risk. This strong statistical evidence confirms that the dataset is well-behaved, with no significant skewness or heavy tails. The distribution of data allows for reliable risk modelling and supports regulatory compliance assessments. With most samples showing effective doses below safety thresholds, groundwater in the investigated area poses no significant radiological health risk to the population, except for a few localized exceedances that warrant further monitoring.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflicts of Interest\u003c/h2\u003e \u003cp\u003eThe authors declare no conflicts of interest regarding the publication of this paper.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003ePJ: Conceptualisation, manuscript preparation and supervisionMW: Design of experiment HW: Sample acquisition and analysisFP: Critical revision of manuscriptDK: Interpretation of results\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThe authors thankfully acknowledge the financial assistance for the study from the Postgraduate Studies, Research and Innovation Committee, Papua New Guinea University of Technology.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAsadi Mohammad Abadi, A., Rahimi, M. and Jabbari-Koopaei, L. (2021). Measurement of dissolved radon concentration in groundwater samples of Shahre Babak city and estimation of annual effective absorbed dose. \u003cem\u003eJournal of Radiation Safety and Measurement\u003c/em\u003e, \u003cem\u003e10\u003c/em\u003e(3), 31-38. doi: 10.22052/9.3.31.\u003c/li\u003e\n \u003cli\u003eBelete, G. D., \u0026amp; Anteneh, Y. A. (2021). General Overview of radon Studies in Health hazard Perspectives. \u003cem\u003eJournal of Oncology\u003c/em\u003e, \u003cem\u003e2021\u003c/em\u003e, 1\u0026ndash;7. https://doi.org/10.1155/2021/6659795\u003c/li\u003e\n \u003cli\u003eCharoensri A., Siriboonprapob S. and Sastri N. (2015) Analysis of radon in shallow-well water: a case study at Phichit subdistrict in Songkhla province, Thailand. Journal of Physics: Conference Series 611 (2015) 012025. https://doi:10.1088/1742-6596/611/1/012025\u003c/li\u003e\n \u003cli\u003eChen, J. (2019). A DISCUSSION ON ISSUES WITH RADON IN DRINKING WATER. \u003cem\u003eRadiation Protection Dosimetry\u003c/em\u003e. https://doi.org/10.1093/rpd/ncz035\u003c/li\u003e\n \u003cli\u003eEPA (2016) Quick Guide To Drinking Water Sample Collection, United States Environmental Protection Agency, 2\u003csup\u003end\u003c/sup\u003e Ed.\u003c/li\u003e\n \u003cli\u003eEU (2001) EU Recommendation on the protection of the public against exposure to radon in drinking water supplies. \u003cem\u003eOff. J. Eur. Communities\u003c/em\u003e 344, 85\u0026ndash;88\u003c/li\u003e\n \u003cli\u003eFelix Pereira B., Jojo Panakal John, Shameka Banta, Simeon Ifu, David Kolkoma (2024) Evidence of Radon Emission Associated with 7th October 2023 Earth quake off the Coast of Madang in Papua New Guinea, Interdisciplinary Journal of Papua New Guinea University of Technology (IJPNGUoT) 1(1),37-42.\u003c/li\u003e\n \u003cli\u003eDavid Kolkoma and Felix Pereira (2023) Assessment of dose rate using gamma ray observations in the mining waste samples of Simberi gold mine in Papua New Guinea, \u003cem\u003ePollution Research,\u0026nbsp;\u003c/em\u003e42 (1) : 7-11.\u003c/li\u003e\n \u003cli\u003eJojo, P. J., Philip Epemu Victor, Pereira, F. B. and Gabriel Anduwan (2019) Radon in Dwellings of Papua New Guinea: Observations of a Preliminary Study, \u003cem\u003eInternational Journal of Environmental Science and Development\u003c/em\u003e, 10(6); 188-192.\u003c/li\u003e\n \u003cli\u003eMoreno, V., Bach, J., Baixeras, C., \u0026amp; Font, L. (2014). Radon levels in groundwatersandnaturalradioactivityinsoils of the volcanic region of La Garrotxa, Spain. Journal of Environmental Radioactivity, 128,1\u0026ndash;8. Epub November 13, 2013. doi:10.1016/j.jenvrad.2013.10.021\u003c/li\u003e\n \u003cli\u003eOnoja, E. D., Onyekachi, G. A., Ejila, A. O., Okoh, P., \u0026amp; Jack, Z. K. (2024). Measurement of Radon Gas Concentration in Sources of Drinking Water in Makurdi, Benue State, Nigeria Using Radon Detector (RAD-7). \u003cem\u003eUMYU Scientifica\u003c/em\u003e, \u003cem\u003e3\u003c/em\u003e(3), 322\u0026ndash;332. https://doi.org/10.56919/usci.2433.034\u003c/li\u003e\n \u003cli\u003eRani, S., Kansal, S., Singla, A. 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K. and Ravikumar P (2010) Radon concentration in groundwater of Varahi and Markandeya River basins, Karnataka State, India.\u0026nbsp;\u003cem\u003eJ Radioanal Nucl Chem\u003c/em\u003e 285:343\u0026ndash;351.\u003cbr\u003ehttp://doi.org/10.1007/s10967-010-0573-x\u003c/li\u003e\n \u003cli\u003eThe World Health Organization. WHO handbook on indoor radon: a public health perspective. In Hajo Z, Ferid S (eds). Geneva; WHO Press. 2009.\u003c/li\u003e\n \u003cli\u003eUNSCEAR 2000, United Nations Scientific Committee on the Effects of Atomic Radiation 2000 Sources and Effects of Ionizing Radiation vol. 1 (New York: United Nations)\u003c/li\u003e\n \u003cli\u003eUNSCEAR 2008 Sources and Effects of Ionizing Radiation 2008 (New York: UNSCEAR)\u003c/li\u003e\n \u003cli\u003eWHO (2017) WHO Guidelines for Drinking-Water Quality, the Fourth Edition Incorporating the First Addenda. World Health Organization, Geneva, Switzerland.\u003c/li\u003e\n \u003cli\u003eYong-jun Ye, Xiang-qian Xia, Xin-tao Dai, Chun-hua Huang \u0026amp; Qian Guo (2019) Effects of temperature, salinity, and pH on \u003csup\u003e222\u003c/sup\u003eRn solubility in water. \u003cem\u003eJournal of Radioanalytical and Nuclear Chemistry. 320, 369\u0026ndash;375.\u003c/em\u003e\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Dissolved radon, water, RAD8, ingestion dose, inhalation dose, effective annual dose","lastPublishedDoi":"10.21203/rs.3.rs-9145612/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9145612/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eRadioisotopes in drinking water raise several serious concerns for human health and environment. Surface and underground sources of water contain natural radionuclides in varying levels depending on the geology of the region on earth and their origin. Primordial radionuclide \u003csup\u003e226\u003c/sup\u003eRa leaches from the geographical bodies and releases its gaseous progeny radon (\u003csup\u003e222\u003c/sup\u003eRn) into ground water in contact with. Radon in water also originates from dissolution of airborne radon into water and other higher radon bearing water in-flows in the catchment area. Aquatic organism intake radionuclides, which may lead to bioaccumulation, genetic mutations, and reproductive issues in them. It is a well-accepted fact that inhalation of indoor radon and its progeny have significant lung cancer risk for human beings. Ingesting radon-contaminated water may contribute to the development of carcinoma in internal organs, particularly within the gastrointestinal tract. Tap water and shower usage are among the primary sources of indoor radon exposure, as they release radon directly into the household air. Assessing dissolved radon in water is essential for evaluating potential health risks and ensuring environmental safety. We report the results of active measurements conducted using the Rad8 Radon Detector to quantify radon levels in drinking water samples collected from 53 locations in the city of Lae in Papua New Guinea. The method adopted is nascent in its method. The results show that the dissolved radon concentration varies from 3\u0026thinsp;\u0026plusmn;\u0026thinsp;1 to 44\u0026thinsp;\u0026plusmn;\u0026thinsp;5 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with an average 24\u0026thinsp;\u0026plusmn;\u0026thinsp;7 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Dissolved radon concentrations in majority of samples were between 18 and 32 Bq l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Estimated annual effective dose of radiation from radon exposure due to dissolved radon in water was 0.15 \u0026plusmn; 0.04 \u0026micro;Sv y\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e which poses no health risk upon consumption.\u003c/p\u003e","manuscriptTitle":"Quantifying dissolved radon in drinking water using an augmented method","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-26 17:15:14","doi":"10.21203/rs.3.rs-9145612/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ca4de26e-0379-47c4-8e67-270b99cf5e2e","owner":[],"postedDate":"March 26th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Revision requested","date":"2026-05-04T18:40:35+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-04T18:54:51+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-26 17:15:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9145612","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9145612","identity":"rs-9145612","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}