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Background Awareness of the dangers associated with exposure to high radiation in the environment is necessary to avoid its health impact, especially when staying in-door. Method Assessment of gamma dose rate and radionuclides in urban settings of Ota has been carried out using a hand-held gamma detector to determine the hotspot of high radionuclides concentration in the study area. In this study, eighteen (18) stations were covered, gamma dose rate and radio-nuclides (Uranium-238, Thorium-232, and Potassium-40) emitting from the subsurface were measured. Results The result showed that the mean value for the measured dose rate of 45.06 nGh−1 is below the suggested value of 84 nGh−1 while the estimated mean values for the radionuclides are were 23.81, 45.35 and 77.82 Bq/kg respectively. The evaluated radium equivalent (Raeq), internal index (Hin), external index (Hex) and gamma index (Iy) ranges from 70.92 to 128.70 Bq/kg, 0.24 to 0.41, 0.19 to 0.35 and 0.25 to 0.46 respectively. Furthermore, the estimated value of the alpha index ranged between 0.05 and 0.15, and an annual effective dose rate from 0.33 to 0.55. The estimated mean value of excess cancer lifetime risk is 0.0015. Conclusions Therefore, the study suggests that the study area is safe for the residents. However, radioactivity concentration emanating from the subsurface of the setting should be monitored to avoid the environmental-health implication of accumulation of low gamma-dose, which can cause cancer of the lung due to anthropogenic activities.

Chemical toxicity risks from 14 different brands of building materials such as Cements, tiles, marbles and sands were analysed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This study is aimed at determining the risk exposure to dweller of different age groups. The digested samples analysed using ICP-MS for the concentrations of Cr, Pb, Zn, Ni, Fe, As and Cd varies from 10 to 183, 8.96 to 68.70, 35.4 to 733.7, 14.4 to 690.5, 0.95 to 4.64 and 0.7 to 14.7 mgkg−1respectively. Statistical Analysis showed that 44% of the Concentrations of Toxic metals measured in the building material samples come from Ni, the scree plots of dermal and inhalation risks exposure to children aged from 0.5 to 11 years showed sharp drop after Ni metal compared to adult with ages ranges from 12 to 70 years where the drop is steady from the first factor. This indicated that Adults are not over-exposed compared to children to these heavy metals. The High factor value of 2.786 was seen in Goodwill Verified. Tile High factor scores were discovered from the exposure of children to both dermal and inhalation risks compared to the Adults. Some of these concentrations and risks exceed the permissible limits of the European Regulatory Standards and USEPA. Significantly, these chemical toxicity risks of heavy metal contents in the building materials may pose health risks on dwellers especially the under-aged children.

The concentrations of lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni), B and Fe in twenty (20) different brands of bottled water samples were investigated to ascertain the risk exposure to consumers using Atomic Absorption Spectrometry (AAS). The concentrations of the heavy metals analyzed varied from bottled water to bottled water samples. The BE bottled water sample was found to contain the least concentration of Pb with a value of 0.0232 mg/l. The risk of chronic daily intake (CDI) was determined based on the United State Environmental Protection Agency (USEPA) model for health risk. It was observed that Fe, Mg and Ca reported in all the bottled water samples. The estimated Chronic Daily Intake (CDI) of different metals from the water samples is found to be in order of magnitude of Pb> Fe>Cd>Ni. The highest CDI found in VA, SO, SO, LAT water samples are higher than the International Reference Dose Level according to WHO and USEPA respectively. This study suggest that some bottled water factories should be sited in zones that are safer from these heavy metals if Reverse Osmosis machine for proper removal of these trace elements from the raw water is not in use for water treatment.

Understanding the background concentration of heavy metals in dust samples is so much important for identifying and managing pollution. Thus, these concentrations in dust can be distributed indoors and outdoors in order of magnitudes. This study demonstrates the risk analysis of dust samples collected from selected buildings in both Covenant University and Canaanland using Atomic Absorption Spectrometer (AAS). The obtained concentrations were used to determine the Geoaccumulation, Contaminant Factor and the Pollution Loading Index (PLI). The highest geo-accumulation index and pollution loading index of 3.108 and 0.5836 due to chromium (Cr) contents in the dust samples were noted in Lecture Theatre 2 (LT2). The higher values found in LT2 may be due to the wide open of both doors and windows. Both the Geo-accumulation Index and Pollution Load Index were found to be lower than the permissible level suggested by World Health Organization (WHO) and United State Environmental Protection Agency (USEPA). Significantly, these observations from this study will provide the basis for the background concentrations and potential risks of some important heavy metals of environmental concern