Assessment of contamination levels, potential ecological and human health risks due to trace elements pollution in the vicinity of the Lolodorf uranium deposit, Southern Cameroon.

The current study assessed the contamination levels and associated ecological and health risks due to hazardous trace elements in soils from Awanda and Mvengue, located in the vicinity of the Lolodorf uranium deposit in Southern Cameroon. Qualitative and quantitative analyses of the soil samples were performed using energy-dispersive X-ray spectrometry. The results indicated that the mean concentrations of metallic and trace elements in soil samples increased in the following order: U < As < Th < Pb < Cu < Ni < Zn < Cr < Mn < Fe < Al.

Radionuclides distribution in soils and radon level assessment in dwellings of Mungo and Nkam Divisions, Cameroon.

Radionuclide and radon levels have been investigated in soil samples and residential environments within the Mungo and Nkam Divisions of the Littoral Region. These analyses employed gamma spectrometry facilitated by a NaI (Tl) detector for soil samples, yielding average activity concentrations of Ra, Th, and  K at 23.8, 72, and 105 Bq kg, respectively.

Thoron exposure in the radon-thoron prone area of the Adamawa Region, Cameroon.

The radon-prone area of the Adamawa region is characterized by high radon concentrations, where no low-risk area was observed. This study aims to investigate about indoor thoron concentration in this area, using RADUET detectors, thoron progeny monitors and DTPS/DRPS. The indoor thoron concentration ranged between 17 and 1000 Bq m, with an average of 131 Bq m.

Effective dose assessment due to inhalation of Rn, Rn, and their progeny: highlighting the major contribution of thoron in a thoron-prone area in Cameroon.

To assess public exposure to radon, thoron, and their progeny, measurements were conducted in 50 dwellings within the bauxite-rich area of Fongo-Tongo in western Cameroon. Passive integrating radon-thoron discriminative detectors (specifically RADUET) were employed for radon and thoron measurements. Additionally, concentrations of short-lived radon and thoron progeny were estimated using Direct Radon Progeny Sensors (DRPSs) and Direct Thoron Progeny Sensors (DTPSs) based on LR-115 detectors.

IoT-based monitoring system and air quality prediction using machine learning for a healthy environment in Cameroon.

This paper is aimed at developing an air quality monitoring system using machine learning (ML), Internet of Things (IoT), and other elements to predict the level of particulate matter and gases in the air based on the air quality index (AQI). It is an air quality assessor and therefore a means of achieving the Sustainable Development Goals (SDGs), in particular, SDG 3.9 (substantial reduction of the health impacts of hazardous substances) and SDG 11.

Chemical weathering and CO consumption in the upper Nyong Basin rivers (Central Africa): Insights on climatic and anthropogenic forcing in humid tropical environments.

A hydrological and hydrochemical database (produced by the M-TROPICS critical zone observatory) in the upper Nyong Basin from 1998 to 2017 was used to evaluate the river's response to climatic and anthropogenic forcing and examine chemical weathering processes. SiO and HCO constitute about 85 % of the Total dissolved solids (TDS) load, equivalent to 0.12 × 10 kg.

Cosmic-ray exposure assessment using particle and heavy ion transport code system: case study Douala-Cameroon.

According to UNSCEAR, cosmic radiation contributes to ~16% (0.39 mSv/y) of the total dose received by the public at sea level. The exposure to cosmic rays at a specific location is therefore a non-negligible parameter that contributes to the assessment of the overall public exposure to radiation.

Simultaneous measurements of radon, thoron and thoron progeny and induced cancer risk assessment in Djeno, Pointe-Noire, Republic of Congo.

In this study, the activity concentrations of radon (222Rn), thoron (220Rn) and thoron progeny were measured simultaneously in Djeno (Pointe-Noire, Republic of Congo) using RADUET detectors to evaluate the air quality and the radiological risks due to the inhalation of these radionuclides. Activity concentrations of radon progeny were calculated from those of radon. Indoor radon, thoron and progenies followed a lognormal distribution ranging between 20 and 40, 6 and 62, 8 and 17.

Transient fertilization of a post-Sturtian Snowball ocean margin with dissolved phosphate by clay minerals.

Marine sedimentary rocks deposited across the Neoproterozoic Cryogenian Snowball interval, ~720-635 million years ago, suggest that post-Snowball fertilization of shallow continental margin seawater with phosphorus accelerated marine primary productivity, ocean-atmosphere oxygenation, and ultimately the rise of animals. However, the mechanisms that sourced and delivered bioavailable phosphate from land to the ocean are not fully understood. Here we demonstrate a causal relationship between clay mineral production by the melting Sturtian Snowball ice sheets and a short-lived increase in seawater phosphate bioavailability by at least 20-fold and oxygenation of an immediate post-Sturtian Snowball ocean margin.

Mapping in a radon-prone area in Adamawa region, Cameroon, by measurement of radon activity concentration in soil.

The radon-prone area of the Adamawa region in Cameroon is characterized by high natural radiation background resulting from the high concentrations of radium-226, thorium-232, and indoor radon. To produce a radon-risk map, radon measurements in soil were carried out in the city of Ngaoundere. The radon activity concentration in soil gas ranged from 256 to 166 kBq m with a mean of 80 kBq m and a standard deviation of 38 kBq m.

INDOOR RADON (222RN) MEASUREMENTS AND ESTIMATION OF ANNUAL EFFECTIVE DOSE IN MVANGAN LOCALITY, SOUTH CAMEROON.

The present work was aimed at measuring indoor radon activity concentrations in dwellings in Mvangan locality, South Cameroon, in order to assess the extent of measures that may be necessary for controlling public indoor radon exposure in this area. Measurements were carried out using passive solid-state nuclear track detectors (RADONAVA Inc., RadTrak2, Sweden) following ISO 11665-4 standard.

Assessment of organ and effective doses received by adult patients undergoing computed tomography in three hospitals in Brazzaville, Congo Republic.

The present study aimed to evaluate adult patient data collected from three hospitals in Brazzaville, Congo Republic, for the purpose of estimating organ and effective doses for each included examination type. A total of 1277 adult patients (aged 16-97 years) who underwent head, chest, abdominopelvic (AP), chest-abdomen-pelvis (CAP), and lumbar spine computed tomography scans were considered. The organ and effective doses were estimated using a Monte Carlo-based method.

Soil gas radon, indoor radon and its diurnal variation in the northern region of Cameroon.

Soil gas radon and indoor radon measurements have been carried out in Mayo-Louti and Benoué Divisions in northern Cameroon. Concentrations of radon in soil have been measured using Markus 10 at the depth of about 1 m. Radon concentration in soil varies from 0.

Natural radioactivity in building materials, indoor radon measurements, and assessment of the associated risk indicators in some localities of the Centre Region, Cameroon.

The objective of the current study is to investigate the natural radioactivity of some building materials, the resulting long-term external and internal effective dose equivalents (EEDE and IEDE) analysis followed by indoor radon measurements, and the assessment of some radiological risk indicators associated with radon exposure. A total of 37 samples of building materials were analyzed with a sodium iodide detector (NaI (Tl)), and the computer code RESRAD-BUILD was used for the analysis of the EEDE and IEDE of the structural elements of the houses (walls and floor). For indoor radon measurements, 140 houses were selected, and in each of them was placed 01 RADTRAK dosimeter.

Assessment of trace elements pollution and their potential health risks in the cobalt-nickel bearing areas of Lomié, East Cameroon.

A study of trace elements pollution in the cobalt-nickel mining area of Nkamouna-Kongo (East Region of Cameroon) and their intimation to the risk of human exposure was carried out. A large spatial variability of concentrations was observed in the geochemical analysis of the trace elements in the thirty samples investigated. Trace element pollution in the investigated samples was assessed using the Regional Screening Level calculator of Environmental Protection Agency (USEPA) and the collected sample were analyzed using a SPECTRO XEPOS Energy Dispersive X-Ray Fluorescence analyzer (ED-XRF).

Preliminary study of black carbon content in airborne particulate matters from an open site in the city of Yaoundé, Cameroon.

A light absorbing reflectometer was used to calculate black carbon (BC) mass concentrations contained in both fine and coarse particulate matters (PM and PM) collected in an urban area of Yaoundé from 1st March 2018 to 26th February 2019 to highlight BC fluctuation and determine its potential predominant sources. The highest BC concentrations were obtained on 14/02/2019 (5.37 µg/m) and 17/01/2019 (3.

Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations.

A long-term measurement technique of radon exhalation rate was previously developed using a passive type radon and thoron discriminative monitor and a ventilated type accumulation chamber. In the present study, this technique was applied to evaluate the thoron exhalation rate as well, and long-term measurements of radon and thoron exhalation rates were conducted for four years in Gifu Prefecture. The ventilated type accumulation chamber (0.

"Early earth" structural data from the Memve'ele area in the northwestern Congo Craton (Ntem complex-southwestern Cameroon).

Structural data, meso‑ and micro-photographics were collected from Archean basement of the Memve'ele area (Ntem Complex, southwestern Cameroon). The analyses were acquired using field and laboratory investigations. Meso-photographics were obtained by a camera Canon , 16X digital zoom, HD 16.

Indoor Radon Measurements Using Radon Track Detectors and Electret Ionization Chambers in the Bauxite-Bearing Areas of Southern Adamawa, Cameroon.

The current work deals with indoor radon (Rn) concentrations and ambient dose-equivalent rate measurements in the bauxite-bearing areas of the Adamawa region in Cameroon before mining from 2022. In total, 90 Electret Ionization Chambers (EIC) (commercially, EPERM) and 175 Radon Track Detectors (commercially, RADTRAK2) were used to measure Rn concentrations in dwellings of four localities of the above region. A pocket survey meter (RadEye PRD-ER, Thermo Scientific, Waltham, MA, USA) was used for the ambient dose-equivalent rate measurements.

The Importance of Direct Progeny Measurements for Correct Estimation of Effective Dose Due to Radon and Thoron.

Radon (Rn), thoron (Tn), and thoron progeny (TnP) were measured in seven inhabited areas of the uranium and thorium bearing region of Lolodorf, located in southwestern Cameroon. Then the equilibrium factor (F) between thoron and its progeny was determined in order to show the importance of direct progeny measurements for correct estimation of effective dose due to radon, thoron and their progenies. A total of 220 RADUET detectors were used to measure indoor radon and thoron and 130 TnP monitors for thoron progeny indoors.

Compositions and mobility of major, δD, δO, trace, and REEs patterns in water sources at Benue River Basin-Cameroon: implications for recharge mechanisms, geo-environmental controls, and public health.

Hydro-geochemical data are required for understanding of water quality, provenance, and chemical composition for the 2,117,700 km Niger River Basin. This study presents hydro-geochemical analysis of the Benue River Basin, a major tributary of the Niger River. The distribution of major ions, Si, δD, and δO, trace and rare-earth elements (TE and REEs, respectively) composition in 86 random water samples, revealed mixing of groundwater with surface water to recharge shallow aquifers by July and September rains.

Simultaneous measurements of indoor radon and thoron and inhalation dose assessment in Douala City, Cameroon.

Radon, thoron and associated progeny measurements have been carried out in 71 dwellings of Douala city, Cameroon. The radon-thoron discriminative detectors (RADUET) were used to estimate the radon and thoron concentration, while thoron progeny monitors measured equilibrium equivalent thoron concentration (EETC). Radon, thoron and thoron progeny concentrations vary from 31 ± 1 to 436 ± 12 Bq m, 4 ± 7 to 246 ± 5 Bq m, and 1.

NATURAL RADIATION EXPOSURE TO THE PUBLIC IN MINING AND ORE BEARING REGIONS OF CAMEROON.

Within the framework of a joint research project on natural radiation exposure and its health effects in Cameroon from 2014 to 2017, the Institute of Geological and Mining Research and the Hirosaki University worked together to carry out natural radiation survey in mining and ore bearing regions of Cameroon. Air kerma rates were measured using car-borne survey method. In-situ gamma spectrometry was used to determine activity concentrations of 238U, 232Th and 40K in soil.