Excess Cancer Research Articles

The radioactive contamination of ground and surface water near a uranium mine in Malawi

Ground and surface water in the uranium mining area of Kayelekera in Malawi was assessed for concentration levels of radioactive metals. Potential health risks associated with the intake of these metals in drinking water from various sources were also estimated. Surface, groundwater and mine discharge water samples were collected and analysed for radio elemental concentration using inductively coupled plasma mass spectrometry analytical technique. The results indicated a high concentration of 238U in water samples from lower Sere river. The activity concentrations of 238U, 232Th and 40K were however below WHO recommended limit. Health risk assessment using average committed effective dose were below the global average. Excess lifetime cancer risk values with an average of for borehole water was calculated and found to be below the global average. Radiologically, the water quality of Kayelekera area post uranium mining activities has not been compromised, however close monitoring and treating of drinking water is recommended

Natural radionuclide content in horticulture plants from former tin mining land and health risk assessment: A case study on Bangka Belitung Island, Indonesia

As a tin producer in Indonesia, Bangka Belitung has abandoned tin mining land containing natural radionuclides, and its use for cultivating horticultural crops has health risks. The aim of the research was to determine the contribution of former tin mining land to natural radionuclide contamination in horticultural products and to assess the radiation hazards by determining the annual effective dose and excess lifetime cancer risk (ELCR). The methodology includes sampling vegetables, fruit, and tubers from several villages in Bangka. Measurement of natural radionuclides using a Gamma Spectrometer at their specific energy. The research results showed that the radionuclides Ra-226, Th-232, K-40 were found in vegetables, fruit, and tubers samples. The highest Ra-226 was found in bitter melon and spinach, Th-232 in cassava leaves, spinach, and bitter melon, while K-40 in bitter melon, spinach, cassava leaves, papaya leaves, mustard greens. The activity rank of Ra-226, Th-232, and K-40 is shown in tubers > vegetables > fruit. The total annual effective dose (AED) from vegetable and fruit consumption is 0.6330 mSv/year, as recommended by UNSCEAR (1 mSv/year), except consumption of tubers (galangal). The ELCR value of vegetable, fruit, and cassava (tubers) consumption is 1.08x10−3; 0.75x10−3; and 0.42x10−3, as recommended by the ICRP.

Studies on radionuclides in soil samples of of Tiruvannamalai District Tamilnadu, India using Gamma Ray Spectrometry

The activity concentrations of natural radionuclides 226Ra, 232Th, and 40K in soil samples from Tiruvannamalai district, Tamil Nadu, have been estimated using NaI (TI) detector-based gamma spectrometry. The mean activity concentration of 232Th in soil samples is greater and poorer for 226Ra and 40K, respectively, when compared with world average values. Radiation hazard estimation was done by the assessment of radiological parameters such as radium equivalent activity (Raeq), absorbed gamma dose rate (DR), annual effective dose rate (HR), and excess lifetime cancer risk (ELCR). These parameters were compared with international criteria. The findings in the soil showed that there is no major radiological risk to the general public by using these soil samples from the Tiruvannamalai district.

Radiological Risk Assessment of Soil Using RESRAD-OFFSITE Code in Communities around Indorama Fertilizer Company Eleme, Port-Harcourt, Rivers State, Nigeria

Anthropogenic activities around a fertilizer company can cause elevation in the concentration of naturally-occurring radioactive materials (NORMs) within surrounding soils, as a result of effluent discharge or heaping of rocks used as raw materials. The aim of this study was to evaluate the human risk associated with exposure to NORMs in soils from communities around Indorama Fertilizer Company Eleme, Port-Harcourt, Rivers State, Nigeria. A sodium-iodide doped with thallium [NaI(TI)] detector was used to measure activity concentrations of these NORMs in 22 soil samples within the study area. The residual radioactivity (RESRAD) offsite modeling program(version 4.0) was then used to estimate the radiation doses and the cancer morbidity risk of uranium-238 (238U), thorium-232 (232Th) and potassium-40 (40K) for hypothetical resident farmer scenario. According to the RESRAD prediction, the maximum total effective dose equivalent (TEDE) during 100 years was found to be 2.82 x 10-5 mSvy-1 at year 12, while the maximum total excess cancer morbidity risk for all the pathways was 3.52E-08 at year 6. Therefore, results obtained from the RESRAD-OFFSITE code in this study has shown that the health risk from effluent discharge within the study area is within acceptable levels according to international standards.

Carcinogenicity of asbestos-free talc and talcum powder: A systematic review of the epidemiological evidence after the 2006 monograph of the International Agency for Research on Cancer.

in 2006, the International Agency for Research on Cancer (IARC) concluded that the evidence of carcinogenicity for asbestos-free talc was inadequate (group 3), whereas perineal use of talcum powder was classified as possibly carcinogenic (group 2B). to assess whether later studies provide more solid information on the carcinogenic risk from asbestos-free talc and talcum powder and a better characterization of exposure. systematic review. cohort studies of talc miners and millers exposed to asbestos-free talc, as well as cohort and case-control studies reporting cancer risk in talc powder consumers published from 2006 onwards were identified through PubMed and reference lists. Pooled analyses were included, but not reviews and meta-analyses. In the case of repeatedly reported studies, the article with the longest follow-up or the largest number of observed cases was selected for data abstraction. Notice was taken of studies which were both reported individually and included in pooled analyses. publications meeting inclusion criteria were: 2 cohort studies on talc miners and millers, 10 cohort studies on talcum powder users (4 of which estimated ovarian cancer risk), and 14 case-control studies (13 on ovarian and 1 on endometrial cancer) on the risk from talcum powder use. No excess cancer mortality has been reported among asbestos-free talc miners and millers. Case-control studies consistently led to estimates of ovarian cancer excesses associated with the use of perineal talcum powder (odds ratios up to 1.5). Most studies quantifying exposure also provided evidence of a dose-response relationship. Individual cohort studies estimated hazard ratios (HR) just above 1. In an analysis of pooled cohorts for a total of 3,112 cases, the HR for women with patent reproductive tract was 1.13 (95%CI 1.01-1.26) with a correlation between HR and frequency of use (p for trend 0.03). In all cohort studies, the perineal use of talcum powder was measured only once in the early phases of follow-up, thus producing an inaccurate measure of cumulative exposure. Results of epidemiological studies regarding cancer risk in other organs are limited and inconsistent. epidemiological studies updated or published after IARC 2006 evaluation indicate that: no increase in cancer risk is apparent among miners and millers of asbestos-free talc; risk for ovarian cancer increases following the perineal use of commercial talcum powder. A correlation between indicators of quantity of use and cancer risk is suggested by a number of studies. The composition of talcum powders considered in such studies is not known.

Evaluation of Appropriate Conditions for Efficient Simultaneous Determination of US EPA and EU Priority Polycyclic Aromatic Hydrocarbons in Various Food Categories and Assessment of Their Consumption Risk.

The QuEChERS (quick, easy, cheap, effective, rugged and safe) conditions were optimized for efficient determination of the U.S. Environmental Protection Agency (US EPA) and European Union (EU) priority polycyclic aromatic hydrocarbons (PAHs) for the categories of grains, tuber & starchy vegetables, soy beans and products, fish & seafood, and poultry & meat, including raw materials and their corresponding products. The PAHs were analyzed using ultrahigh-performance liquid chromatography with temperature-controlled fluorescence detection and gas chromatography with tandem mass spectrometry. The established conditions had good accuracy, repeatability, and precision. Environmental pollution and processing methods influence the level of PAHs in samples. The low molecular weight PAHs were present in all raw materials, and processing increased high and low molecular weight PAHs in the products. The excess cancer risk for consumption of PAHs in cooked samples was mostly acceptable; a small number of samples might be of slight concern in certain age groups.

Assessing radioactive contaminants in Kathmandu soils: measurement and risk analysis.

Soil samples from vegetable farmland in densely populated wards of Nepal were analyzed for natural radionuclide levels, employing a NaI(Tl) 3" [Formula: see text] 3" gamma detector. The study aimed to evaluate the causes of radiation risk, attributing it to soil contamination resulting from the rapid urbanization and concretization that followed the earthquake in 2015. The activity concentration of radium-226, thorium-232, and potassium-40 and the ranges observed are 2.080±0.084-33.675±1.356 Bq kg[Formula: see text], 17.222±0.198-119.949±1.379 Bq kg[Formula: see text], and 11.203 ± 0.325-748.828±21.716 Bq kg[Formula: see text], respectively. The average values obtained for hazard indices are as follows: radium equivalent activity (82.779 Bq kg[Formula: see text]), absorbed dose rate (36.394 nGy h[Formula: see text]), annual effective dose equivalent (0.045 mSv yearr[Formula: see text]), gamma index (0.291), external hazard index (0.224), internal hazard index (0.253), excess lifetime cancer risk (0.159), annual gonadal dose equivalent (243.278 mSv year[Formula: see text]), alpha index (0.054), and activity utilization index (0.716). However, in most places, thorium-232 concentration is greater than those of the world average and recommended values. In specific locations such as Ward 4 in Baluwatar, the soil was found to have concentrations of Ra[Formula: see text] and K[Formula: see text] exceeding recommended limits. Despite this localized concern, the overall analysis of hazard indices across the studied areas revealed that most values were within permissible limits. This suggests that, on a broader scale, radiation exposure may not be a significant concern in the investigated regions. Nonetheless, the study recommends regular monitoring in additional locations to ensure a comprehensive and ongoing assessment of radiation levels.

Radiological hazards assessment associated with granitoid rocks in Egypt

The present study aimed to assess the radioactive hazards associated with the application of granitoid rocks in building materials. An HPGe spectrometer was used to detect the levels of the radioactive elements uranium-238, thorium-232, and potassium-40 in the granitoid rocks. The results showed that the levels of these elements were lower (38.32 < 33 Bq kg−1), comparable (47.19–45 Bq kg-1) and higher (992.26 ≫> 412 Bq kg−1) than the worldwide limits for 238U, 232Th, and 40K concentration, respectively. The exposure to gamma radiation of granitoid rocks was studied by various radiological hazard variables like the absorbed dose rate (Dair), the outdoor and indoor annual effective dose (AEDout and AEDin), and excess lifetime cancer risk (ELCR). A variety of statistical methods, including Pearson correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA) was used, to study the relationship between the radioactive elements and the radiological hazards. According to statistical analysis, the main radioactive risk of granitoid rocks is contributed to by the elements uranium-238, thorium-232, and potassium-40. Granitoid rocks can be applied in building materials, but under control to prevent risk to the public.

Radiological landscape of natural resources and mining: Unveiling the environmental impact of naturally occurring radioactive materials in Ghana's mining areas

This study provides a general observation of the status of naturally occurring radioactive materials (NORMs) distribution in mining and industrial areas of Ghana in order to establish regional and national data on NORMs. The study includes data on radioactivity concentrations of U-238, Th-232, and K-40 in soils and for water concentrations of Ra-226, Th-228, and K-40 from various mining, oil, and gas communities, as well as water sources used for crop farming and farmlands. The average activity concentrations of U-238, Th-232, and K-40 in the soil samples were found to be 59 ± 16 Bq/kg, 48 ± 15 Bq/kg, and 286 ± 57 Bq/kg, respectively. The average concentration of Ra-226, Th-228, and K-40 in the water samples were found to be 1.62 ± 0.33 Bq/L, 2.08 ± 0.53 Bq/L, and 22.36 ± 3.44 Bq/L, respectively. The estimated average annual effective doses from external and internal exposure pathways in soil and water samples were 0.09 mSv/y and 0.54 mSv/y, respectively. The total annual effective dose resulting from both exposure pathways was calculated to be 0.63 mSv/y, which is below the 1 mSv/y dose limit recommended by the International Commission on Radiological Protection (ICRP) for controlling public radiation exposure. Based on the radiological hazard indices, the majority of the soil samples were found to be suitable as building materials as their respective indices were below the limits except for two sample locations and the sludge and scale samples. The average Excess Lifetime Cancer Risk (ELCR) value of the water samples was 1.6 times greater than the recommended value of 1.16 × 10−3, presenting a relatively higher risk to the public of developing cancer. No significant regional differences in the levels of radioactive elements. The regression models demonstrate strong interrelationships between the studied elements, with high R-squared values suggesting a predictable nature of one element’s concentration based on others.

Investigation of natural radioactivity in soil of selected hospitals in Imo State, Nigeria

We measured the terrestrial activity contents, radiation doses; hazard indices and excessive lifetime cancer risk (ELCR) from primordial radionuclides (226Ra, 232Th and 40K) in 50 soil samples collected from the five selected hospitals within Imo State, Nigeria. Radioactivity measurements were carried out by the method of gamma-ray spectrometry with thallium doped sodium iodide [NaI(Tl)] detector. The mean activity values obtained for the radionuclides 226Ra, 232Th and 40K (respectively) in Federal Medical Centre, Owerri (FMC); General Hospital, Umuguma, Owerri West, (GHW); Neuroscience Hospital, Ohaji Egbema (NHO); St. Joseph Hospital, Okigwe (SJH); Imo State University Teaching Hospital, Orlu (IMSUTH) are: 20.56±4.73, 14.96±3.42 and 105.65±31.40 Bqkg-1; 11.77±3.03, 17.45±4.20 and 63.67±18.44 Bqkg-1; 17.97±4.65,10.02±2.18 and 190.43±42.83 Bqkg-1; 11.36±3.71, 17.39±4.46 and 76.29±25.08 Bqkg-1; and 11.84±3.64, 4.89±2.25 and 165.18±58.41 Bqkg-1 respectively. These values were below the worldwide average values: 32 Bqkg-1 for 226Ra, 45 Bqkg-1 for 232Th, and 412 Bqkg-1 for 40K as documented by UNSCEAR (2000). 40K recorded the highest mean activity compared to 226Ra and 232Th in the studied soil samples. Radium equivalent activity (Raeq), absorbed gamma dose rate (Dr), annual effective dose equivalent (AEDE), external hazard index (Hex), gamma representative index (Ιϒr) and annual gonadal dose equivalent (AGDE), were calculated to quantify the radiation risk to the public from exposure to 226Ra, 232Th and 40K in the studied samples. In addition, excess lifetime cancer risk (ELCR) was also accessed. The mean computed values of the excess lifetime cancer risk for FMC, GHW, NHO, SJH and IMSUTH are 0.08±0.03, 0.09±0.15, 0.10±0.2, 0.10±0.03 and 0.07±0.02 respectively. The mean values of these hazard parameters were within the acceptable safety limits provided for human safety and environmental protection.

Research Progress and Controversy on the Relationship Between Iodine Excess and Thyroid Cancer Occurrence

Research Progress and Controversy on the Relationship Between Iodine Excess and Thyroid Cancer Occurrence

Radon levels and dose assessment at the basement workplaces of hospitals in different regions of Taiwan

The basements of large hospitals in Taiwan are usually working areas for image radiometry, radiation therapy, and nuclear medicine, where the radon concentration can be accumulated. This study investigated radon concentrations in the basement working environments of 30 hospitals in different regions with various geology of Taiwan, aiming to explore the relationship between geological conditions and radon concentrations and estimate the radiation dose received by the working staff. Portable MR107+ semiconductor radon detectors calibrated with a radon chamber were used for radon measurement at the hospital basement working areas according to the protocol of MAH-2019 instrument placement recommendations from the US EPA. The excess lung cancer risk (ELCR) as well as the lung cancer cases per million persons (LCC) were further derived from the radiation dose.The basement working areas investigated are located on the first to sixth underground floors of hospitals in Taiwan mainland and islands, Penghu and Kinmen. The 222Rn concentration higher than 100 Bq/m3 was observed at CH-1 (122.1 Bq/m3) in Changhua City and CY-1 (114.7 Bq/m3) in Chiayi City. This is attributed to that the central air conditioning systems of these hospitals were turned off during off-duty hours. The radon concentrations of all hospitals were lower than the action level, 150 Bq/m3, regulated by the US EPA. No significant relationship was found between radon concentration and the geological characteristics of the measured sites. That is, the ventilation of the basement working areas in hospitals is more important than local geological characteristics on indoor radon concentration, and therefore proper ventilation is crucial for reducing radon gas concentration in the hospital basements. Estimated annual effective dose from 222Rn for the hospital staff was higher than 1 mSv/y at YL (1.24 mSv/y), CH-1 (1.64 mSv/y), CY-1 (1.54 mSv/y), CY-2 (1.34 mSv/y), and PH-2 (1.14 mSv/y), and that for the rest sites was <1 mSv/y. The maximum mean ELCR was found to be 0.63% at CH-1, and the related LCC was estimated to be 29.5 per million persons.

Assessing the adverse impacts of biodegradable plastic bags: Chemical elements and radionuclides considerations

Biodegradable plastic (BP) products are considered potential substitute for conventional plastics and are increasingly used in various fields and applications. However, concerns remain regarding their safety and potential impact on the humans and ecosystems. This research examined pristine BP shopping bags (collected from local market in Jeddah, Kingdom of Saudi Arabia) for their elemental content and natural radionuclides, 40K, Th, and U, using neutron activation analysis. The results obtained revealed that BP bags contain higher mass fractions of potentially toxic elements (e.g., Cr, Co, Ba, Zn, Mn, V, Cd, Mo), halogens (Br and Cl), and natural radionuclides compared to conventional plastic bags. To assess the potential human health risks associated with BP shopping bags, the radiological and elemental hazards were evaluated by calculating the relevant hazard indices over a long exposure period. For non-carcinogenic risks, the average daily intake of each element through different exposure pathways, as well as the hazard quotient, hazard index, and total exposure hazard index, were estimated. For carcinogenic risks, the incremental lifetime cancer risk was calculated. Possible hazards arising from radiological exposure were assessed by determining the excess lifetime cancer risk and other indices. Overall, the results showed that BP bags don’t pose a significant radiological or elemental threat to human health. However, attention should be given for controlling and monitoring the Cr content in BP bags. For more accurate health risk assessment, studies on leaching of chemical elements and radionuclides under different environmental and biological conditions will be carried out in future works.

Evaluation of radiological health risk caused by the use of fly ash in cement and concrete production and its storage

ABSTRACT As a result of firing pulverized coal in thermal power plants, enormous amounts of fly ash (FA) are produced as industrial waste. The release into the atmosphere and storage of this industrial waste remains one of the major environmental problems that threaten human health by contributing to air, water, and soil pollution. The recovery and reuse of FA in the construction industry is the only economic solution to the existing problem. In this study, the potential radiological risk caused by the usage of FA in concrete and cement production as a main component and its storage in landfill sites was evaluated for people and works by estimating radiological parameters (activity concentration and alpha index, annual effective doses, and the corresponding excess lifetime cancer risks) based on activity concentrations of terrestrial radionuclides in FA. Also, the radiological risk to the workers working in the FA landfill site was evaluated using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of terrestrial radionuclides in FA samples from the Tunçbilek lignite coal-fired thermal power plant at Kütahya province of Turkey were measured as 417, 156 and 454 Bq kg−1 for 226Ra, 232Th and 40K, respectively. When using up to 35% by mass of FA in cement and concrete, the average values of the radiological parameters revealed that they were within the recommended safety limits. However, code estimations showed that a regular worker in FA storage would be exposed to a total effective dose rate greater than 3 mSv y−1.

Multi-kingdom microbial signatures in excess body weight colorectal cancer based on global metagenomic analysis

Excess body weight (EBW) increases the risk of colorectal cancer (CRC) and is linked to lower colonoscopy compliance. Here, we extensively analyzed 981 metagenome samples from multiple cohorts to pinpoint the specific microbial signatures and their potential capability distinguishing EBW patients with CRC. The gut microbiome displayed considerable variations between EBW and lean CRC. We identify 44 and 37 distinct multi-kingdom microbial species differentiating CRC and controls in EBW and lean populations, respectively. Unique bacterial-fungal associations are also observed between EBW-CRC and lean-CRC. Our analysis revealed specific microbial functions in EBW-CRC, including D-Arginine and D-ornithine metabolism, and lipopolysaccharide biosynthesis. The best-performing classifier for EBW-CRC, comprising 12 bacterial and three fungal species, achieved an AUROC of 0.90, which was robustly validated across three independent cohorts (AUROC = 0.96, 0.94, and 0.80). Pathogenic microbial species, Anaerobutyricum hallii, Clostridioides difficile and Fusobacterium nucleatum, are EBW-CRC specific signatures. This work unearths the specific multi-kingdom microbial signatures for EBW-CRC and lean CRC, which may contribute to precision diagnosis and treatment of CRC.

Risk assessment-based verification of the CertiPURTM limit values for toluene diamine and methylene dianiline in flexible polyurethane foam.

Flexible polyurethane foams (PUF) are used in many consumer products. PUF may contain trace levels of aromatic diamine impurities that could represent a potential health risk. The risk associated with sleeping on a PUF mattress was evaluated. Toxicity benchmarks for sensitization and non-cancer endpoints were derived from the respective points-of-departure using standard assessment factors. For the cancer endpoints, toxicity benchmarks were derived from the 25th-percentile values of animal studies. Recently published emission and migration data allowed to link exposure with the CertiPURTM voluntary quality limits of ≤5mg.kg-1 for 2,4-toluene diamine and 4,4'-methylene dianiline in PUF. Using conservative exposure scenarios, lifetime-average daily internal doses from the combined inhalation and dermal exposures were calculated. Margins of safety for non-cancer and sensitization endpoints were >104. The theoretical excess cancer risk was ≤1.5 × 10-7. It is concluded that sleeping on a mattress that satisfies the CertiPUR limit value does not pose undue risk to consumers.

Simulation of excess lifetime cancer risk due to the presence of radon in groundwater in Wamba town of Wamba local government area, Nasarawa state, Nigeria

The measurements of Radon concentration in ten groundwater (4-wells and 6-boreholes) from Wamba town of Wamba Local Government Area of Nigeria had been carried out. The annual effective dose (AED) and the Excess Lifetime Cancer Risk (ELCR) due to ingestion of the groundwater was established to ascertain the risk outcome from the samples. Radon concentration was detected using RAD7. The minimum Radon concentration was 0.146 Bql-1 while the maximum was 0.474 Bql-1 with mean average of 0.3134 Bql-1 which are within the United States Environmental Protection Agencies (USEPA) 11.1 Bq/L recommendation. Moreso, the maximum and minimum Annual Effective Dose (AEDing) was 3.5×10^(-6) and 1.10×10^(-6) Sv/yr which are also within the 0.1 mSv/yr World Health Organization (WHO) recommendation, while the maximum and minimum Excess Lifetime Cancer Risk (ELCR) was 1.44×10^(-5) and 4.50×10^(-6) respectively. Cumulative probability simulation of the Excess Lifetime Cancer Risk (ELCR) was carried out using Oracle Crystal Ball software validated by 10 and 90% percentiles. Comparison of all the results with the European Union (EU)/World Health Organization (WHO) value of 500 Bq/L recommendation revealed that all the samples analyzed have Radon concentration below the recommended limit. The average mean Radon concentration in the ten locations from Wamba Town are within the recommended levels as confirmed by the simulation results. At 10% Probability, the highest risk was found in Event center (1.26×10^(-5)) while the lowest was found in the water sample collected from Angwan dalatu (1.05×10^(-6)) while at 90% probability the highest (1.62×10^(-5)) and lowest (1.37×10^(-6)) risk was found in the same Events center and Angwan dalatu. Though there is variation in the results based on locations which means that the concentration of Radon gas depends on the geological nature of the bedrock and generally increases with the uranium concentration in the local geology. The Excess Lifetime Cancer Risk (ELCR) dose results are far lower than the UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiations) recommended maximum contamination level of 0.003875. Therefore, no indication of any likelihood of cancer incidence as a result of waterborne radon within the studied community that may demand urgent intervention from radiological point of view.

Background Ionization Radiation Of Selected Water Factories In Yenagoa Metropolis Bayelsa State

The research work was carried out at the water factories of both Allen T. water factory and Niger Delta University (NDU) water factory in Bayelsa State, Nigeria. Radiation Monitoring Device- Radalert x100 was deployed in carrying out the study. The water factories were partitioned into ten different locations as indicated in the both Tables. The Background Ionizing Radiation (BIR) mean value of 0.016 mSv/y was recorded at Allen T. water factory as against the BIR mean value, 0.013 mSv/y as recorded at Niger Delta University (NDU) water factory. The mean Absorbed dose rate (AbD) of 0.140 nGy/h was recorded at Allen T. water factory as against the AbD mean value, 0.110 nGy/h as recorded at Niger Delta University (NDU) water factory. Annual effective dose equivalent (AEDE) mean value of 0.215mSv/y was recorded at Allen T. water factory which is quite higher than the Annual effective dose equivalent (AEDE) mean value of 0.168 mSv/y as recorded in Niger Delta University (NDU) water factory. The Excess life cancer risk (ELCR) mean value of 0.593 x10-3 recorded at Allen T. water factory was higher than the Excess life cancer risk (ELCR) mean value, 0.464 x10-3 as recorded at Niger Delta University (NDU) water factory. The values obtained were then compared to the World Permissible Limit as given by UNSCEAR 2000. The high radiological values as recorded at Allen T. water factory is mainly because of poor ventilation system, the absence of steel-coated equipment’s in the factory and the location of the factory close to human activities thereby contributing to the high-level of radiation.

Assessment of Natural Background Radiation Exposure in the Federal Capital Territory of Nigeria

The detrimental effects of environmental contamination and deterioration on health are a worldwide concern and Nigerian environmental and public authorities continue to be concerned about the risk to public health. The water, the sky, construction materials and the earth's crust all release natural background radiation that contaminates the environment around us. Additionally, people are exposed to background radiation that comes from internal, cosmic, and terrestrial sources, although, the altitude determines the amount of cosmic radiation exposure, and high altitudes result in large radiation doses. Monitoring the amounts of radiation to which humans are exposed, either directly or indirectly, requires an understanding of the natural background radiation in the environment. The current study attempted to create a baseline of outdoor background radiation in FCT for exposure rate, absorbed dose rate, annual effective dose equivalent, and excess life cancer risk. The study used a very sensitive survey meter to measure the BIR. The average BIR value found in the research areas is marginally below the 0.013mRh-1 global BIR level, indicating an almost high BIR level for the FCT while the absorbed dose rates of 105.85nGy/hr was greater than the 59nGy/hr global population weighted average gamma dose rates estimate. The obtained annual effective dosage equivalent value is greater than the global average normal annual effective dosage level for outdoor environments, and the excess lifetime cancer risk values were higher than the 0.29×10-3 allowable level as reported by UNSCEAR &amp; ICRP. Therefore, the general people and those who live in environmentally sensitive areas may experience immediate health effects from contamination and radiation levels at the current rates.

Evaluation of Radioactivity Contents and Excess Lifetime Cancer Risk Due to Ingestion from Natural Radionuclides in Maize Samples from Some Selected Maize Farms in Ekiti State, Nigeria

The study was carried out to evaluate the radioactivity concentrations of 40K, 232Th and 238U in five maize samples collected from maize farms within Ekiti State, Nigeria. The activity concentration measurements were determined using n – type co-axial HPGe detectors for the state. The activity concentrations were found to vary from 994.67 – 2457.01 Bq Kg-1 for 40K, 32.84 – 91.88 Bq kg-1 for 232Th and 43.21 – 97.77 Bq kg-1 for 238U respectively. The annual effective dose to individuals from the consumption of the Maize was estimated on the basis of the measured radionuclides content in the food crop which ranged between 0.41 and 1.51 m Svy-1 respectively. The value1.04 m Svy-1 were obtained for the state as the mean total annual effective dose. The mean excess life time cancer risk was also calculated to be 2.06x10-9 . The value was compared with the internationally acceptable limits and found to be far less to the maximum permissible dose of 1.0 x10-3 recommended for the public by the United Nations Scientific Committee on the Effects of Atomic Radiation. Hence, the maize was found to be safe for human consumption.