Radiological Assessment of Soils on the Waysides of the Road Underconstruction in Ijebu-Ode, Ogun State, Southwestern Nigeria

The ongoing road construction and rehabilitation of major highways in Ijebu-Ode involved the grading, refilling of the roads with different types of soils and the use of various materials that may be radioactive. Therefore the construction and the rehabilitation of the roads may lead to enhancement of the natural radioactivity levels in the area. Soil samples were collected from the sideways of the roads and analysed using a single crystal 0.51cm x 0.51cm NaI (Tl) detector, manufactured by Scintitech Instrument, USA, is coupled through a Hamamatsa (R1306NSV3068) photomultiplier tube to a Multichannel Analyser, MCA (2100R:01) manufactured by Price gamma Technology, USA. The activity concentrations in the entire area of study were 396.1±70.9 Bqkg-1, 17.7±4.6 Bqkg-1, and 33.9±6.7 Bqkg-1 for 40K, 226Ra and 232Th respectively. The absorbed dose rate and the outdoor effective dose rate were 27.6±5.5 nGyh-1and 33.9±6.7µSvy-1 respectively. The collective health detriment was 1.1 x 10-4. The radiological health effect on the populace in the area were insignificant as the results showed very low radioactivity levels and collective health detriment indicated that 11 out of 100,000 people were vulnerable to any type of cancer. Keywords: Impact assessment, natural radioactivity, road constructions, health detriment, Nigeri

Radiological Impact Assessment of Farm Soils and Ofada rice (Oryza sativa japonica) from Three Areas in Nigeria

            يزرع الارز الاسيوي والمسمى ب (ارز اوفادا )في مجتمعات المسماة (أراموكو ، وأباكاليكي وأوفادا) ويستهلكها كل من الفقراء والأغنياء في نيجيريا على حد سواء . تم تحديد ما مجموعه عشرين مزرعة من أراضي الأرز في كل منطقة من مناطق الدراسة ، وتم جمع عينات من الأرز بشكل عشوائي ، وتم خلطها بشكل دقيق لتقديم عينة من كل أرض زراعية. تم جمع عينات التربة في كل مزرعة على عمق 5-15 سم من ثماني نقاط مختلفة على الأقل وتم خلطها معًا لتشكيل العينة. تم التحليل الطيفي لهذه العينات. تم استخدام كاشف أشعة كاما NaI (Tl) ذو معايرة جيدة في التحليل الطيفي للعينات واستخدمت الإحصاءات الوصفية لتحليل النتائج.لقد كان متوسط التركيز الاشعاعي للعناصر  40K,232Th,238U , هو 261.8±52.5Bq/kg      و   9.6±1.2Bq/kg و 8.7±1.0Bq/kg (أوفادا)،257.3±39.0Bq/kg،9.3±1.1Bq/kg و 7.8±1.8Bq/kg (أباكاليكي) و 248.2±54.8Bq/kg،9.3±0.9Bq/kg،7.6±1.5Bq/kg (أراموكو) على التوالي اما تراكيز النشاط الاشعاعي في التربة للعناصر  40K,232Th,238U ,كانت 333.9±62.8Bq/kg،11.1±1.1Bq/kg و 11.0±1.4Bq/kg (اوفادا) ،306.8±36.0Bq/kg،10.7±0.8Bq/kg و 9.4±1.8 Bq/kg (أباكاليكي) و 321.8±42.4Bq/kg،10.9±0.5Bq/kg و9.5±0.6Bq/kg (أراموكو). تم تسجيل أعلى متوسط جرعة 106.0±8.0µSv/y والجرعة الفعالة في الهواء الطلق البالغة32.4±3.40µSv/y في  Ofada. وان أعلى معدل لخطر الاصابة بسرطان قدره (0.33±0.004) x10-3 تم تسجيله في (أراموكو). أشارت النتائج إلى أن جرعة  النويدات المشعة أقل بكثير من الحد العالمي البالغ   290µSv/y  ومخاطر انخفاض السرطان عن الحد الذي أوصى به UNSCEAR وهو 0.29x10-3 ، وبالتالي فإن استهلاك الأرز ofada من المناطق قد لا يشكل أي تأثير صحي خطير.Oryza sativa japonica (ofada rice) is largely grown in Aramoko, Abakaliki and Ofada are communities and consumed by both the poor and rich in Nigeria. A total of twenty ofada rice farmlands were identified in each study area and rice samples were randomly collected, thoroughly mixed to make a representative sample from each farmland. Soil samples were collected in each farm to a depth of 5-15cm from at least eight different points and thoroughly mixed together to form a representative sample. The samples were thereafter taken to the laboratory for preparation and spectroscopic analysis. A well-calibrated NaI(Tl) gamma-ray detector was used in spectrometric analysis of the samples and descriptive statistics was used to analyze the results. The respective mean 40K, 238U and 232Th activity concentrations in the rice were 261.8±52.5Bq/kg, 9.6±1.2Bq/kg and 8.7±1.0Bq/kg (Ofada); 257.3±39.0Bq/kg, 9.3±1.1Bq/kg and 7.8±1.8Bq/kg (Abakaliki); and 248.2±54.8Bq/kg, 9.3±0.9Bq/kg and 7.6±1.5Bq/kg (Aramoko). The respective mean 40K, 238U and 232Th activity concentrations in the soils were 333.9±62.8Bq/kg, 11.1±1.1Bq/kg and 11.0±1.4Bq/kg (Ofada); 306.8±36.0Bq/kg, 10.7±0.8Bq/kg and 9.4±1.8 Bq/kg (Abakaliki) and 321.8±42.4Bq/kg, 10.9±0.5Bq/kg and 9.5±0.6Bq/kg (Aramoko). The highest mean ingestion dose of 106.0±8.0µSv/y and outdoor effective dose of 32.4±3.40µSv/y were recorded in Ofada community. The highest mean ingestion cancer risk of (0.33±0.004) x10-3was recorded in Aramoko. The results indicated significantly lower radionuclide ingestion dose than the world limit value of 290µSv/y and lower cancer risks than the UNSCEAR recommended limit of 0.29x10-3, therefore consumption of ofada rice from the areas may not pose any serious health impact

Radiological and related chemical health impact assessments of uranium in pipe borne water from some waterworks in Lagos metropolis, Nigeria

The common purifying technique of water for public (human) consumption in Nigeria is by chlorination which only eliminates the microbial contaminants, but the radioactive contaminants remain unaffected. There had been no serious radiological and related chemical health impact assessments of pipe borne water in the country. Water samples were collected from five waterworks across Lagos Metropolis and a single crystal NaI (Tl) detector was used to determine the activity concentration of 238U radionuclide in the water. The radiological health impact assessment determined includes annual effective dose rates and risk of incurring cancer. Using activity concentrations obtained and the relation from United State Environmental Protection Agency (USEPA), the chemical health impact such as life average daily dose (LADD) and hazard quotient (HQ) due to ingestion of 238U in water were determined and data were analyzed using descriptive statistics. The mean 238U activity concentrations were 15.3±4.1 Bql-1, 14.6±5.2 Bql-1, 9.7±2.0 Bql-1, 11.0±2.9 Bql-1 and 11.3±1.8 Bql-1 for Agege, Shomolu, Iju, Saka and Amuwo respectively. The least mean effective dose, 0.3±0.1 mSvy-1 was obtained in Iju while the highest, 0.5±0.2 mSvy-1 was obtained in Agege and Shomolu. The least mass concentration of 174.2±35.7μgl-1 was obtained in Iju and the highest of 274.9±73.3 μgl-1 was obtained in Agege. The highest mean cancer mortality and morbidity risks, (0.6±0.2) x10-3 and (0.9±0.2) x10-3 respectively were obtained in Agege. The activity concentrations of radionuclide in the water were low hence the morbidity and mortality risks in the study were low when compared to the world average value of 1.0x10-3. The result showed high radioactivity and chemical levels therefore caution and control should be taken to avoid any health crisis later in future.Keywords: uranium impact assessment, pipe born water, water works, Lagos metropolis, Nigeri

Activity and Corresponding Mass Concentrations of 40 K and 238 U in Well Waters from Ago-Iwoye, Ogun State, Nigeria

Abstract Ago-Iwoye, situated on the basement complex has similar geological setting to Abeokuta which had been reported to be significantly high in radioactivity when compared to the world's average. The major source of water for the populace in Ago-Iwoye was from the wells dug at different locations across the town. The 238 U and 40 K concentrations in the water samples were measured using gamma-ray spectroscopy method and the health risks due to consumption of the waters were determined. The mean activity concentrations were 25.1±10. . The cancer mortality and morbidity risks were less than the reported world average of 1.0x10 -3

Assessment of external and internal doses due to farming in high background radiation areas in old tin mining localities in Jos-plateau, Nigeria

Farming on soils situated in high background radiation areas can result to enhanced radiation exposure scenarios and pathways to humans. To assess the likely levels of exposures, farm soil samples were collected from different farmlands in three old tin mining localities (Bitsichi, Bukuru and Ropp) in Jos Plateau Nigeria, known for high radiations. The soil samples were analyzed for the activity concentrations of 226Ra, 232Th and 40K, using gamma-ray spectroscopy. The outdoor annual effective dose rates were calculated using the activity concentrations of the radionuclides and were found to vary from 0.07 mSv to 2.02 mSv across the three localities. Considering dust generation from soil tillage and inadvertent ingestion of soil particles, the likely internal radiation hazards were estimated using conservative dust and soil loading factors. The total average annual effective dose rates due to 226Ra and 232Th that could result from dust inhalation and ingestion of soil particles were 16.9 µSv, 8.1 µSv and 8.8 µSv, respectively for Bitsichi, Bukuru and Ropp. Though these values are about 5% the outdoor exposures to the farmers in those farms and greater than 1 µSv y-1, from the point of view of radiation protection and risk, they are significant. It suffices to say, therefore, that the results of this study will create the possibility of the importance to evaluate the health risk among the farming population and workplace environments which often is not covered by regulations concerning health protection