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In order to ensure radiation monitoring and protection, an investigation and assessment of radiological risks that may be associated with the consumption of table waters commonly consumed in Ilorin, Nigeria, was carried out. The activity concentration level of 238U, 232Th, and 40K was determined using thallium activated 3˝×3˝ [NaI(TI)] detector connected to ORTEC 456 amplifier. The radiological risks due to the consumption of the samples were then estimated. The highest annual effective dose (AED) values were obtained from VW and the minimum was obtained from UW water. The AED decreases in the order VW>HW>IW>MW>DW>UW. This implies that VW water constitutes more radiation exposure followed by HW, IW, MW, DW, and then UW Water. The values estimated for MW, DW, and UW water were all lower than the world average value of 1 mSv/y and hence pose no serious radiation hazard. While the values estimated for VW, IW, and HW waters were slightly higher than the recommended threshold value, suggesting a possible risk of radiation exposure to customers. The Excess Lifetime Cancer Risks corroborated the findings of the AED, implying that the probability of developing cancer is high for most of the water samples. Since the values of the estimated hazard parameters were mostly higher than the recommended limits for all age groups, it is recommended that public water system should be monitored and efforts should be made to educate and enlighten the public on radiation exposure, its health effects, and remedial actions necessary to reduce radionuclides concentration in drinking water.

This study aimed to assess the radiological health implications to humans due to the use of kaolin from kaolin mines in Nigeria. A calibrated RS-125 spectrometer was used in-situ to monitor the activity concentrations of 40K, 238U, 232Th and dose-rate of kaolin minefields in Ilorin-south and Ilorin-west, Nigeria. The in-situ monitoring and measurements were done in 90 locations selected at random in the study areas. The in-situ measurements were consolidated via laboratory analysis of 48 samples of Kaolin bricks using lead-shielded NaI(Tl) detector. The estimated average values for all radiological hazard parameters for the in-situ measurements of Ilorin-west are higher than that of Ilorin-south minefield. However, the opposite was the case with the laboratory analysis of the bricks. This apparent conundrum was due to the higher values of 238U observed in the samples of bricks from Ilorin-south. In addition, the measured activity concentration of the primordial radionuclides in the Kaolin bricks from both mines are lower than the on-site measurements. This was attributed to the contribution from other terrestrial materials on-site. The 5th, 50th, and 95th percentiles of the cumulative probabilities for the excess lifetime cancer risk using the Monte Carlo simulation are 167.00 × 10–6, 281.00 × 10–6, 414.00 × 10–6 for Ilorin-west (in-situ), 104.00 × 10–6, 232.00 × 10–6, 392.00 × 10–6 for Ilorin-south (in-situ), 706.00 × 10–6, 1,250.00 × 10–6, 1,900.00 × 10–6 for Ilorin-west (lab), and 742.00 × 10–6, 1,480.00 × 10–6, 2,460.00 × 10–6 for Ilorin-south (lab), respectively. Therefore, the cancer risks are within the acceptable limits for both mining sites. This study is useful in developing radiation risk assessment models for decision makers in different fields of environmental sciences.

The present study combined analysis of satellite, aeromagnetic and radiometric data for evaluation of structural features within the Ife-Ilesha schist belt. Shuttle Radar Topographic Mission digital elevation data have been enhanced using hill-shading technique for the delineation of morphological features. The superposition of total gradient amplitude lineaments on the 3-D Euler deconvolution map revealed the trends and depth of structural features within the study region. The major trends are NE–SW, NNE–SSW, E–W and minor trends in the N–S direction, including the Ifewara shear zone that trends in the NNE–SSW. The estimated depths to the top of the sources within the shear zone varies from 90 to 200 m. Complementary analysis of the airborne radiometric data revealed that the Ifewara shear zone and adjacent regions are characterized by radiometric anomalies, indicating regional mineralization alteration zone. Generally, there is a good correlation between the satellite, radiometric, aeromagnetic maps which provides new insights and re-evaluation of structural features.

This work investigates the activity concentration of 238U, the ambient gamma absorbed dose rates (DR), and the 222Rn concentration levels in ground and surface water samples from gold and lead mining area of Moro, Kwara State, Nigeria. In situ measurements of activity concentration of 238U and DR were carried out using Super SPEC RS-125 gamma spectrometer and 222Rn activity concentration in ground and surface waters were analysed using a calibrated RAD7 big bottle system. The results show that the risk of radiation exposure at the mining area is high and the public are not safe from exposure to ionizing radiation.

Dye-sensitized solar cells (DSSCs) which fall under the category of the third generation solar cells have been extensively studied because of the presume low cost, simple methods of preparation, low levels of toxicity and ease of manufacturing. However, due to their low conversion efficiency: relatively low performance compares with other photovoltaic devices, and unpromising-long-term stability, this hampers it usage on a commercial or industrial scale. The highest efficiency ever recorded for a DSSC material was about 12% using Ru(II) dyes when its material and structural properties were optimized. However, this efficiency is less when compared to the efficiencies of the first and second generation of solar cells, (thin-film solar cells and first generation (Si-based) solar cells) whose efficiency were about 20–30%. This article therefore provides an overview of the operational principles, light harvesting and trapping technologies, and recent advancesof the DSSCs. We highlighted the reasons it should be given much research attention, some improved light harvesting and trapping technology, operating principle, component of DSSC and lastly, the highlight of the future prospective alongside the need to revisit the associated problems of low stability, scalability, and low efficiency.

Since mining activities are known to contribute immensely to human exposure to ionizing radiation of terrestrial origin, the berylium mining site in Ifelodun is believed to cause radiological impacts. Forty-eight samples of surface and ground waters were collected within this area and analyzed in order to assess radon (222Rn) radioactivity level and its associated effective doses. The 222Rn activity concentration in the ground and surface waters were analyzed using a calibrated RAD7-active electronic detector big bottle system. The fact-findings from the mean Radon concentration and the estimated annual effective doses for adults, children, and infants reveals values that were mostly above the recommended limits set by regulatory bodies. The order of radiological risk follow the pattern infant > children > adult. All the estimated values of the cancer risks for both surface and ground water using the Monte Carlo simulation are higher than the recommended value of 0.2 (× 10−3) provided by ICRP and UNSCEAR. Owing to this radiation risk, strict and effective measures need to be put in place to safeguard populace in the area and the workers in the mining site.

High-resolution airborne magnetic data of Oyo Metropolis has been used to map subsurface geological features which in most cases, corresponds to the area of interest for mineral expedition. The airborne magnetic data was first reduced to the magnetic equator (RTE); this is normally done to make the data simpler to interpret. The RTE map was subjected to Fast Fourier Transform to separate the regional and residual magnetic anomalies and estimate their depths. An average depth of 2500 m and 500 m were obtained for the top of regional and residual sources respectively. 3D-Euler deconvolution and tilt derivative interpretation techniques were combined and used on the RTE map, to locate and estimate depths to geologic contacts and pegmatite intrusions attributed to lineaments. The resulting 3D-Euler depth solutions were plotted on the tilt derivative map of the study area. A very good correlation was highlighted, indicating that the methods are good interpretative techniques for mapping magnetic lineaments. The estimated depths obtained from 3D-Euler deconvolution method are in the range of 108.1–544.3 m for structural index 1.0 corresponding to intrusions (dykes), and the result of structural index 0.0 corresponding to geologic contacts are in the range of 5.9–295.2 m. The estimated depth parameters coupled with known geological information, were further used to produce the best image view of the subsurface geological features of the study area, using 2-D profile modeling technique. The result obtained from the 2-D profile model is in good agreement with the results obtained from the 3D-Euler deconvolution and tilt derivative methods, indicating locations and depths of various intrusions (dykes) and geologic contacts. The obtained results from this study will help shed more light into the structural framework of the study area and can help potential explorer target new areas for mineral exploration.

Graphical abstract, In this study, a well calibrated Super-Spec (RS-125) gamma spectrometer was used to measure the activity concentrations of 40K, 238U, 232Th and gamma doses rate at 1 m above the ground level over a granite mining field in Asa, Kwara State, North-central Nigeria. Measurements were carried out in 50 randomly selected sample points. The overall mean activity concentrations of 40K, 238U, 232Th and gamma dose are 570.91, 42.86, 18.15 Bqkg−1, and 60.11 nGyh−1 respectively. The results of the activity concentrations were used to estimate the corresponding radiation hazard parameters to assess the suitability of the granite for building and construction purposes. The data in this study could serve as the baseline radiological data of the region for future references. • Activity concentrations of 40K,238U,232Th and gamma doses were measured over a granite mining field in Asa. • The total mean activity concentrations of the radioisotopes and gamma dose are 570.91, 42.86, 18.15 Bqkg−1, and 60.11 nGyh−1 respectively. • The radiological hazards are higher than the recommended permissible limits.

In an attempt to understand the general structural patterns of Ikogosi warm spring and environs, remotely sensed images have been integrated with high resolution aeromagnetic anomaly dataset. This is because subsurface faults offer pathways for the upward flow of geothermal fluids and imaging these structures where they are concealed provides localized areas for geothermal investigation. Interpretation of the high resolution aeromagnetic, Landsat-8 and Shuttle Radar Topography Mission data has resulted in the detection of structural features within Ikogosi and environs. The enhancement of aeromagnetic anomaly data using total gradient technique facilitated the identification of three distinct geologic trends. This technique offers good information of structural patterns within the region, including the estimated source depths from the source parameter imaging and 3-D Euler deconvolution methods, which ranges from 100 to 860 m. The results show the distribution and direction of lineaments with major N–S, NE–SW and E–W trends within the study area. The combination of the surface lineaments with magnetic depth maps has established that faults around the warm spring interact, connect and act as conduits for the flow of hydrothermal fluids at varying depths which subsequently channel the fluids to an exit fault/lineament on the surface. The result revealed that the Ikogosi warm spring is situated along a major NNE-trending fault with subsidiary minor E-trending faults. These minor concealed subsidiary faults associated with the Ikogosi warm spring provides a follow-up for geothermal investigation within the region.

In this study, determination of magnetic susceptibility were carried out on 366 soil samples using MS2B magnetic susceptibility meter connected to a computer system using MULTISUS2 software. The soil samples were selected from six sites namely: Shell environment, Nigeria Liquefied Natural Gas environment, Port Harcourt Refining Company James Hart, New Jerusalem and Port Harcourt respectively. Three of the six sites; Shell, NLNG and Port-Harcourt Refining Company environments have their soils contaminated with hydrocarbon. One hundred and ninety two (192) soil samples were collected from these hydrocarbon contaminated sites and 174 from non-hydrocarbon contaminated soil (control samples). The magnetic susceptibility values obtained from Shell environment and for hydrocarbon samples showed higher (enhanced) magnetic susceptibility with average values of 117.54x10-8 m3kg-1 and 2016.39x10-8 m3kg-1 and a moderate magnetic susceptibility for with an average value of 20.83x10-8 m3kg-1 in comparison to magnetic susceptibility values obtained from the control samples whose average values were 2.39x10-8 m3kg-1, 12.42x10-8 m3kg-1 and 3.31x10-8 m3kg-1 for James Hart, New Jerusalem and Port Harcourt respectively. This means that the hydrocarbon sites are highly magnetic which could be indication of pollution. The results of the percentage frequency dependent susceptibility (χFD%) obtained in the hydrocarbon samples showed about 16% of the samples had percentage frequency dependent susceptibility (χFD%) values between 0-2%, 53% had values of χFD% between 2-10% and 31% had χFD% between 10-12% and above while about 21% of the control samples had χFD% values between 0-2%, 58% between 2-10% and 21% between 10-12% and above. The high magnetic susceptibility value in the hydrocarbon soil samples is an indication of pollution due to hydrocarbon deposit. The Government is therefore advised to monitor the location and activities of the oil companies and initiate quick mop up strategies should be put in place in the eventuality of oil spillage.

This work contains dataset of measured activity concentrations of 40K, 238U, 232Th and gamma doses at 1 m above the ground level over Beryllium and Gold mining fields in Ifelodun and Moro respectively, Kwara State, North-central Nigeria. A well calibrated Super-Spec (RS-125) gamma spectrometer was used to carry out these measurements. Measurements were carried out manually in 72 randomly selected sample points. Statistical analyses of the data were explored to infer potential statistical relationships. The obtained dataset is presented for further assessment that can offer insights into the safety state of Ifelodu, Moro and their environs from radiation protection point of view. The data in this study could serve as a substantial baseline radiological data of the region for future monitoring and epidemiology researches.

Natural radioactivity measurement and dose assessment are important aspects of radiation protection. The goal of this study is to validate the previous results obtained from the in-situ measurements in the study area in order to ascertain the level of radiation hazards to the populaces living around the mining site.A3 × 3-inch lead-shielded NaI(Tl) detector was used to measure the activity concentrations of 40K,238U and232Thin soil, water and guinea corn grain samples collected from a granite mining field in Asa, Kwara State, North-central Nigeria. The overall mean activity concentrations of 40K,238U and 232Th are 441.06, 11.51 and 15.42 Bqkg−1for the soil samples, 20.67, 0.66, and 0.88 BqL−1 for the water samples and 214.31, 5.25 and 8.86 Bqkg−,1respectively for the grain samples. The bioaccumulation/transfer factors are 0.49, 0.46 and 0.58 for 40K,238U and 232Th respectively. The mean values of all the radiological hazard parameters are within the permissible limit recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation. Consequently, the risk of indoor and outdoor gamma radiation exposure is comparatively less for these Granite soils. Hence, the results in this study will reference future studies in terms of basic radiological data., Atomic physics, Environmental science, Nuclear physics, Granite, Asa, Nigeria, NaI(Tl) detector, Radioactivity, Radiological hazards.

Aeromagnetic data acquired over Ibi area within the Middle Benue Trough, Nigeria, has been interpreted to successfully mapped regional structural features that are favorable for economic mineral deposits. The 3D Euler deconvolution technique provided estimated depth values for the regional structural features while the deduced source parameter imaging gave depth estimates to magnetic basement of the study area. The latter map shows two major sub-basins with depth values between 2700 m and 3300 m. Since the magnetic basement depth estimates could be used as a proxy for the thickness of sedimentary formation of the region, the sedimentary formation is sufficiently thick for fossil maturation and therefore confirms that hydrocarbon exploration may be plausible within the region. The combined assessment of magnetic source edge location and magnetic basement depth values offers valuable information on the subsurface configuration, which is very important for mineral and hydrocarbon exploration within Ibi area.

Silver thin films were prepared on glass substrates using chemical bath method. The thin films were annealed at different temperatures of 100 and 200oC for 1hour. The samples, as-prepared and annealed were characterized using X-ray diffractometer (XRD) and Uv-Vis spectrophotometer. XRD results revealed that silver films present a cubic phase with (111) preferred orientation. The XRD result and analysis also revealed that the intensity of the peaks and the crystallite size increase with increase in annealing temperature. All the films showed very low transmittance within the visible region with the 200oC annealed film having the highest at 1.4%. Reflectance was found to reduce from 65% for the as-deposited film to as low as 17% for the 200oC annealed film within the visible region of the wavelength. The reflectance reduces with increase in annealing temperature. The films also showed low percentage absorbance within the UV region of the wavelength with the 200oC annealed film having the highest absorbance of 2.79%.Keywords: Annealing, Thin films, XRD, Optical properties, Spectrophotometer, Silver

Reliance on structural data from geological mapping will be grossly inadequate to establish an informative regional tectonogenic interpretation in southwestern Nigeria mainly because of poor exposure of outcrops due to severe weathering in the tropical region. Therefore high resolution aeromagnetic anomaly and Landsat-8 OLI/TIRS data were adopted for tectonic analysis of Ikole/Kabba area where qualitative analysis of Landsat-8 imagery provides surface lineaments with major E − W and N–S trends. Processing of the aeromagnetic anomaly data utilizing the horizontal gradient magnitude and total gradient methods indicated various E − W, NW - SE, N–S and NE - SW structural features in agreement with the surface lineaments; lending credence to the existing geologic structural interpretation. The resulting synoptic structural interpretation suggests the preservation of two major successive events; an earlier prominent E-W trending lineaments resulting from a N–S compressional deformation, succeeded by a brittle deformational event characterized by NW-SE and NE-SW trending lineaments. Additionally, the magnetic basement depth map deduced from the source parameter imaging technique shows depth values between 50 m and 650 m, which represent depths to the top of structural features within the basement rocks of the region. The collective interpretation of high resolution aeromagnetic anomaly and Landsat-8 data provides significant information about regional tectonics and structures that are good conduits for mineral deposits within the study area.

This study evaluates health risks associated with Arsenic due to mining activities in parts of North-central Nigeria. 306 samples of soil, water and guinea corn were collected for analysis using Atomic Absorption Spectrometry. The analysis reveals varying concentration of Arsenic that is in most cases, above the acceptable limits of consumption, signifying evidence of pollution. The estimated pollution evaluation indices indicates evidence of pollution due to the mining activities. The estimated values of the bioaccumulation factors are very low. The Average Daily Intake reveals that ingestion pathway is the dominant pathway of exposure. While most of the Hazard Index (HI) estimated for the soil and grain samples are « 1, the HI estimated for the water is ≈1. This therefore, means that the probable non-cancerous effect of Arsenic in the drinking water is high. Based on the Delphii method of classification, the Incremental Lifetime Cancer Risk ranges between level II and level III for the soil and grain samples and between level VI and level VII for the water samples within the study sites. This high cancer risks was confirmed by the mean, 5th and 95th percentiles of the cumulative probabilities using the Monte Carlo simulation.

In this research paper, the sub-surface heat flow of a part of the Chad Basin, in North eastern Nigerian was estimated using spectral analysis. This was obtained from twenty (20) digitized High Resolution Aeromagnetic (HRAM) data sheet covering the study area. Regional-residual separation using first order polynomial fitting method with three coefficients was carried out on the data map before the application of statistical spectral analysis. Result shows that the centroid depth varies between 9.39 km and 18.31 km. The depth to the Curie temperature isotherm varies between 15.14 km and 33.46 km below the mean sea level. It was also found that the Curie temperature isotherm within the basin is not a horizontal level surface but an undulating surface with geothermal gradients and heat flow ranging between 15.77 and 38.31°C/Km, and 39.41 and 95.77 mWm -2 respectively. Thus, the calculated average geothermal gradient and heat flow for this area are 23.39°C/Km and 58.47 mWm -2 respectively. Since average heat flow in thermally normal continental region is 60 and the values in excess of 80 mWm -2 – 100 mWm -2 are associated with anomalous geothermal conditions, hence the study area can generally be considered as a thermally normal region. But, the northeastern part of the study area with values in excess of 80 mWm -2 is recommended for further investigation Keywords: Geothermal energy, Spectral Analysis, Chad Basin. Curie point depth

Natural radionuclides content of 238U, 232Th and 40Kfor water and sediment samples collected from Asa-dam Ilonn. Nigeria weremeasured using Nal(TI) detector. The mean activity concentration in the water samples were 6.05, 3.23 and 9.65 Bql−1 for 238U, 232Th and 40Krespectively. The mean activity concentration of 238U, 232Th and 40Kmeasured in the sediment samples were 7.57, 8.19 and 73.48 Bql−1 respectively. Theactivity concentration of 40Kwas higher than that of 238U and 232Thfor the water and sediment samples. All measured activity concentration and estimated radiological parameters were below world permissible limit values. Therefore, there may be no serious immediate radiological health burden on the environment and the people using the dam.

Radiometric assessment of natural radioactivity concentration around Ijako dumpsite was done using hand held gamma spectrometer. A total of 10 in situ measurements were taken at the site. The U-238, Th-232, and K-40 radioactivity concentration obtained were used to assess the radiological hazard level in the area. Comparing the mean results of radiological parameter obtained with world average; Radium equivalent was far less than 370Bqkg-1, External hazard was less than 1, Annual effective dose equivalent was less than 0.08mSvy-1, Gamma index was less than 1, and Excess life cancer risk was less than 0.29 × 10-3. This implies that Ijako dumpsite poses no radiological hazard to the general public.

Measurement of activity concentration of primordial radionuclides 40K, 232Th, 238U and the corresponding gamma dose rate over a major sharp-sand field in Ilorin, Nigeria, was carried out using Super Spec RS125 gamma ray spectrometer. The RS125 gamma spectrometer gives in-situ measurement of radioactivity concentration. Measurements were taken in 50 locations. The peak values of the measured activity concentrations of 40K, 238U, 232Th, the dose rate (D) and the resulting annual effective dose (AED) are 688.60, 48.17, 30.86 Bqkg−1, 49.50 nGyh−1 and 0.06 mSvy−1 respectively, while their corresponding lowest values are 31.30, 1.24, 0.41 Bqkg−1, 4.70 nGyh−1, and 0.01 mSvy−1 respectively. The estimated mean values of 40K, 232Th, 238U, the gamma dose rate (D) and AED are 454.48, 13.52, 11.63 Bqkg−1, 32.96 nGyh−1 and 0.04 mSvy−1 respectively. Consequently, the mean values of the measured radionuclides and the hazard parameters i.e. dose rate and annual effective dose are within the permissible levels. This follows that the risk of radiation exposure for this location is comparatively less, but the general public may not be safe from exposure to indoor ionizing radiation since no amount of radiation is safe for stochastic effects.

Radionuclides are found naturally in air, water and soil. They are even found in vegetation, consumer products and in human body. Everyone on the planet is exposed to some background level of ionizing radiation through external exposures that occurs as a result of irradiation, and internal exposures that occurs as a result of ingestion and inhalation. Studies have shown that tobacco contains minute quantities of radioisotopes from uranium and thorium-decay series which are radioactive and carcinogenic. Tobacco product increases both external and internal exposure due to these radioisotopes. In fact, tobacco products have been considered to be one of the most significant causes of lung cancer. Owing to the large-scale consumption of tobacco in Nigeria at the present time, locally produced tobacco products in Nigeria were collected from the market and the naturally-occurring 238U and 232Th decay series, as well as non-series decay 40K in these products were measured using γ-ray spectrometer. The radiological impacts of the radionuclides in these products were assessed from their specific activities. The average values of the absorbed dose rate were 19.72 and 17.59 nGy h -1 for snuff and cigarette products respectively. The average values of the effective doses due to daily inhalation of smoke by consumers from one wrap of snuff and one stick of cigarette products is 592.32 and 66.62 μSv yr -1 respectively. Similarly, the values of the radium equivalent activity index for snuff and cigarette samples were 40.95 and 38.95 Bq kg -1 respectively. Also the external radiation hazard index were 0.12 and 0.11 for snuff and cigarette samples respectively while the internal radiation hazard index were 0.17 and 0.15 for the two samples respectively. The average excess lifetime cancer risk (x 10 -3 ) values for daily inhalation of smoke from one wrap of snuff and one (1) stick of cigarette were 2.07 and 0.23 x 10 -3 respectively. The estimated values of some of these parameters were found to be lower than the recommended limit by UNSCEAR (2000). However, the effective dose poses a serious health risk to addicted consumers of the product when three (3) or more wraps of snuff and one (1) or more packs of cigarette products are consumed daily. The mean excess lifetime cancer risks values estimated were also much higher than the recommended limits by UNSCEAR (2000). This then makes the risk of suffering cancer and other radiation injuries to be high. Keywords : Radiological impacts, Tobacco, Cigarette, Snuff, Cancer, Radiation injury, Nigeria.

Radionuclides are found naturally in air, water and soil. They are even found in vegetation, consumer products and in human body. Everyone on the planet is exposed to some background level of ionizing radiation through external exposures that occurs as a result of irradiation, and internal exposures that occurs as a result of ingestion and inhalation. Studies have shown that tobacco contains minute quantities of radioisotopes from uranium and thorium-decay series which are radioactive and carcinogenic. Tobacco product increases both external and internal exposure due to these radioisotopes. In fact, tobacco products have been considered to be one of the most significant causes of lung cancer. Owing to the large-scale consumption of tobacco in Nigeria at the present time, locally produced tobacco products in Nigeria were collected from the market and the naturally-occurring 238U and 232Th decay series, as well as non-series decay 40K in these products were measured using γ-ray spectrometer. The radiological impacts of the radionuclides in these products were assessed from their specific activities. The average values of the absorbed dose rate were 19.72 and 17.59 nGy h-1 for snuff and cigarette products respectively. The average values of the effective doses due to daily inhalation of smoke by consumers from one (1) stick of cigarette and one (1) wrap of snuff products were 66.62 and 592.32 μSv yr-1 respectively. Similarly, the values of the radium equivalent activity index for snuff and cigarette samples were 40.95 and 38.95 Bq kg-1 respectively. Also, the external radiation hazard index was 0.12 and 0.11 for snuff and cigarette samples respectively while the internal radiation hazard index was 0.17 and 0.15 for the two samples respectively. The average excess lifetime cancer risk (× 10-3) values for daily inhalation of smoke from one (1) stick of cigarette and one (1) wrap of snuff were 0.23 and 2.07 × 10-3 respectively. The estimated values of some of these parameters were found to be lower than the recommended limit by UNSCEAR (2000). However, the effective dose poses a serious health risk to addicted consumers of the product and passive smokers in the environment when three (3) or more wraps of snuff and one (1) or more packs of cigarette products are consumed daily. The mean excess lifetime cancer risks values estimated were also much higher than the recommended limits by UNSCEAR (2000). This then makes the risk of suffering cancer and other radiation injuries to be high.

Atomic Absorption Spectrometry was used to analyze the concentrations of heavy metals (Pb, Cd, Cr, Fe and As) in the Catfish and Tilapia from Kiri Dam and River Gongola, Northeastern Nigeria. Analysis of these selected heavy metals in the fish samples reveals that these selected heavy metals are higher in Catfish than Tilapia irrespective of the location. Assessment of the health risks due to consumption of these fishes suggests that both fishermen and the general populace are not subjected to a significant potential health risk. The results of this study regarding metal contents in fishes from the study areas also suggest that the consumption of catfish and tilapia from the study area is not free of risks. And that the complex THQ and TTHQ parameters used in health risk assessment of heavy metals provides a better image than using only a simple parameter like the content of the metals in the samples.

This paper focuses on the production of printed circuit boards for use with both domestic and industrial electronics. The use of printed circuit board (PCB) design software, methods of design transfer to copper boards, etching and post-production tasks were undertaken and are described in detail in this paper. The relevance of this paper is appreciated for its unique ideas and methods of incorporating local technology into modern PCB design with proven reliability, precision and economic advantages.

This study assessed the natural radioactivity and radiological health impact of thirty-eight (38) samples of soil, food and water in Fashina village, Ile-Ife, Osun State, Nigeria using portable survey meter with a Global Positioning System (GPS) and well-calibrated NaI(Tl) detector system The mean exposure rates in the study area were 0.14 μSv hr -1 and 0.12 μSv hr -1 in soil/food and water samples respectively. The mean radioactivity content obtained for 238 U, 232 Th and 40K were 12.14 ± 4.17Bq kg -1 , 23.23 ± 7.67 Bq kg -1 and 270.14 ± 61.79Bq kg -1 respectively in soil samples and 8.56 ± 2.80Bq kg -1 , 13.17 ± 4.48Bq kg -1 and 89.41 ± 24.15Bq L -1 respectively for 238 U, 232 Th and 40K in water samples. The mean values of 30.91, 15.64 and 12.47 nGy h -1 were obtained for the absorbed dose rate in soil, food and water, respectively, while 37.90, 178.79 and 1085.23 μSv y -1 were obtained for the Annual Effective Doses (AED). Similarly, the Radium equivalent (Raeq) were 66.16 Bq kg -1 , 34.28Bq kg -1 and 27.31BqL -1 , in soil, food and water, respectively. The external and internal radiation hazard indices were 0.18 and 0.21, 0.09 and 0.12, 0.07 and 0.09, respectively for soil, food and water. The values obtained for the Excess Lifetime Cancer Risk (ELCR) in (x 10 -3 ) were also 0.13, 0.63 and 3.80 for the soil, food and water samples, respectively. It was found that the values of some exposure rate, radioactivity contents and radiological impact parameters in the study area which were higher than those of the control area and the world average values poses a serious health risk to the environment and its inhabitants. Keywords : Radioactivity, Scrap Metal, Gamma Spectrometry, Radiological Impact Parameter

This study assessed the radioactivity levels and transfer factor of natural radionuclides around iron and steel smelting company located in Fashina village, Ile-Ife, Osun State, Nigeria. This was with a view to evaluate the exposure rate of the study area, determine the radionuclides present and activity concentration (238U and 232Th and 40K) in the samples and evaluate the soil-to-food transfer ratio of the radionuclides. A portable survey meter with a Global Positioning System (GPS) were used for in-situ investigation and a well-calibrated NaI(Tl) detector system was used for the radioactivity measurement of the samples. A total of 38 samples comprising soil, food and water were collected at the study area (Fashina) and control area (Opa) in Osun state, Nigeria for spectrometry analysis. The soil and food samples were oven dried, pulverized and sieved while water samples were acidified with 10 mL of 11 M HCl per litre to prevent adsorption of radionuclides with the wall of the container. All the samples were then sealed and kept for at least 28 days in radon impermeable cylindrical container so as to reach secular equilibrium. The mean exposure rates in the study area were 0.14 µSv hr-1 and 0.12 µSv hr-1 for the control environment. The mean radioactivity content obtained for 238U, 232Th and 40K were 12.14 ± 4.17 Bq kg-1, 23.23 ± 7.67 Bq kg-1 and 270.14 ± 61.79 Bq kg-1 respectively in soil samples and 8.56 ± 2.80 Bq kg-1, 13.17 ± 4.48 Bq kg-1 and 89.41 ± 24.15 Bq kg-1 respectively in food samples. Similarly it was 7.64 ± 2.95 Bq L-1, 10.04 ± 3.43 Bq L-1 and 69.04 ± 15.49 Bq L-1 respectively for 238U, 232Th and 40K in water samples. The transfer factor from soil to food for 238U, 232Th and 40K were calculated from the activity concentrations of soil and food, while the means were 0.73, 0.61, and 0.39 respectively in the study area.

Mining and smelting activities are the main causes for the increasing pollution of heavy metals from water sources. The toxicity of these heavy metals from the mining, milling and smelting companies can cause harmful and even lethal effects on the human health. The objective of this study was to investigate the level of As, Cr, Zn, Mg, Fe, Pb, Cd, Cu, Ag and Mn in well and tap water and assess the degree of pollution in the study area. Atomic Absorption Spectrometry investigation was carried out on 60 samples of water (Well and Tap) collected within and outside the mining and smelting area of Ajaokuta to determine the extent of these heavy metals contamination in their drinking water. The data of heavy metal concentrations reveal that the area has been slightly contaminated with the heavy metals, with As and Cr having the highest level of contamination. Correlation analysis between the selected heavy metals was conducted to further investigate the relationship between the metals. The result shows that these selected metals have common pollution sources related to the mining and smelting activities in the area. Keywords: Heavy metals, atomic absorption spectrometry (AAS), smelting, pollution, well water

Water samples from Hadejia River in the north eastern part of Nigeria were studied in order to ascertain the suitability and radiological safety of water from the river for human consumption. Radioactive measurements, using a lead shielded sodium iodide detector coupled to a multichannel analyzer were used to estimate eight radiological parameters of water samples from Hadejia River. The results show that the values of all the parameters fall within the minimum universal standard, indicating that consuming the water pose no serious radiological hazard, especially for adults. The values of the Absorbed Dose Rate (50.10511 nGyh-1) and AEDE (12.458 mSvy-1) for the infant however portend that infant consumer could be susceptible to radiation hazard on consuming water from the River. It is however recommended that activities that are capable of enhancing the radiological content of the River be avoided within the area.