The use of a Radiation Alert Inspector device and a gamma-spectrometry system fitted with a Sodium Iodide (NaI) detector was used to determine the radioactivity concentration level of natural radionuclides 238 U, 232 Th, and 40 K in soil in several locations in Orlu, Imo State, Nigeria. 19 soil samples were collected for analysis from several locations of factories, agricultural farming-lands, gullies and water eroded areas, and soil deposits very close to flowing waters from rocks, due to environmental concerns arising from human activities in this region. The activity concentration values for 238 U, 232 Th, and 40 K were found to range from 0.14 to 9.34 Bq.kg −1 , 0.03–3.75 Bq.kg −1 , and 16.83–783.06 Bq.kg −1 , respectively, with average mean values of 4.15, 1.64, and 134.13 Bq.kg −1 . Radium equivalent activity, absorbed dose rate, and gamma index mean values for the samples were 16.822 Bq.kg −1 , 8.528 nGyh -1 , and 0.133 mSv respectively, the obtained values were below the safe limit values set by the United Nations Scientific Committee on the Effects of Atomic Radiation of 370.0 Bq.kg −1 , 59.0nGyh −1 , and 1.0 mSv. According to the findings, the regions under study are reasonably safe for human outdoor activities such as agriculture, construction, and factory operations.

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In this paper, a geophysical strategy based on the recently proposed Manta-Ray Foraging (MRF) Optimization algorithm is adapted and presented for the blind computation of depth/shape defining parameters from magnetic anomalies due to buried geo-bodies. The model parameters deciphered are the coefficient of amplitude (K), buried structure’s origin (x0), the depth (z), magnetization angle (α), and a shape factor (q). After detailed and piecewise design, the new inversion tool is originally trial-tested on anomaly data generated synthetically. The uncorrupted version of the test data is first analyzed, then - it is corrupted with noise varied at 5, 10, 15, and 20% corruption levels. Thereafter, it is experimented with magnetic profiles taken from exploration fields in the United States, Peru, and Egypt. From the evaluation of results obtained, the new procedure is observed as exhibiting outstanding stability and flexibility especially with noisy dataset and notable efficiency in the quantitative resolution of magnetic inversion problems. The results obtained for the field cases are also mostly consistent especially when compared with background results from similar studies conducted with other methods; further affirming the new tool as reliable for the geophysical investigation of buried minerals.

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