Heavy metal contamination of selected mining fields in North-Central Nigeria.

This study evaluates the causes, concentration and the associated health risks of selected heavy metals (HMs) in soil samples collected from beryllium and gold mining fields in Nigeria. The samples of soil were collected manually and analysed by means of Atomic Absorption Spectrophotometry (AAS). Seventy-two (72) samples were analysed which presented varying degrees of concentration of the selected HMs. The analysed HMs are Chromium (Cr), Arsenic (As), Iron (Fe), Cadmium (Cd), Nickel (Ni), Manganese (Mn), Magnesium (Mg), Zinc (Zn), Copper (Cu) and Lead (Pb). Deterministic and stochastic approaches were explore to examine the human health risks. The evaluated Hazard Indices (HI) for the investigated mining locations are < 1, the recommended threshold provided by United State Environmental Protection Agency (USEPA) for acceptable non-cancer risk. The estimated cancer risk levels for the mining locations exceeds the acceptable range of 1.00E-6 and 1.00E-4.•Thus, the mining is making significant contribution to HMs pollution, which is dangerous human health.•However, the Monte Carlo simulation (MCS) reveals that the 95th, 50th and 5th percentiles of the cumulative probability of the cancer risks are within the acceptable range.•This work will be useful for decision makers in mitigating heavy metals contamination due to mining activities.

Soil-to-plant transfer of 40K, 238U and 232Th and radiological risk assessment of selected mining sites in Nigeria.

One of the major route through which humans are exposed to ionizing radiation is via food chain, which is consequent of soil-to-plant transfer of radionuclides. This work reported the activity concentrations of 40K, 238U and 232Th in samples of water, soil and guinea corn grains collected from Beryllium and Gold mining sites in Kwara, Nigeria. In-situ measurements at approximately 1 m in the air was carried out using a well-calibrated portable Gamma Spectrometer (Super Spec RS-125), while the soil, water and the guinea corn samples were analyzed using a '3 × 3' inch lead-shielded NaI (Tl) detector. The measured activity concentrations of the natural radionuclides in the soil from both mines are lower than the in-situ measurements. This was attributed to the contribution from other terrestrial materials on-site. The estimated mean transfer factors (TFs) for 40K, 238U and 232Th are 0.21, 0.17 and 0.31, and 0.46, 0.19 and 0.28 respectively for the Beryllium and Gold mining sites. While the TFs for 238U and 232Th exceeded the mean value of 0.0062 and 0.0021 for 238U and 232Th respectively, the TFs for 40K are well below the 0.74 for cereals grains provided by International Atomic Energy Agency (IAEA). The radiation impact assessment using the Monte Carlo simulations reveals values that were generally less than the global average values provided by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Hence, the risk of cancer inducement due to radiation exposure is within the acceptable limits for both mining sites.

Dataset on radioactivity measurement of Beryllium mining field in Ifelodun and gold mining field in Moro, Kwara State, North-central Nigeria.

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.

Radioactivity levels and transfer factor for granite mining field in Asa, North-central Nigeria.

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 40 K, 238 U and 232 Thin 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 40 K, 238 U and 232 Th 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 40 K, 238 U and 232 Th 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.

Natural radionuclides and radiological risk assessment of granite mining field in Asa, North-central Nigeria.

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.

Data on the porphyrin effect and influence of dopant ions on Thaumatococcus daniellii dye as sensitizer in dye-sensitized solar cells.

In this work, data on the effect of porphyrin characteristic of UV/VIS absorption of Thaumatococcus daniellii (T. daniellii) dye-sensitized solar cells sensitized with different electrolytes were presented. The influence of dopants from 1 g/100 ml electrolyte: distilled water and applied time difference of 3 min is observed on the photovoltaic characteristics and performance of the deposited thin film. The output efficiency and incident photon to conversion efficiency of T. daniellii dye-sensitized solar cells was acquired and could be further used as a model for designing dye-sensitized solar models as substitute for silicon solar cells.