Assessing geochemical and natural radioactivity impacts of Hamadat phosphatic mine through radiological indices

Abstract

The utilization of phosphorite deposits as an industrial resource is of paramount importance, and its sustainability largely depends on ensuring safe and responsible practices. This study aims to evaluate the suitability of phosphorite deposits for industrial applications such as the production of phosphoric acid and phosphatic fertilizers. To achieve this goal, the study meticulously examines the geochemical characteristics of the deposits, investigates the distribution of natural Radioactivity within them, and assesses the potential radiological risk associated with their use. The phosphorites are massive and collected from different beds within the Duwi Formation at the Hamadat mining area. They are grain-supported and composed of phosphatic pellets, bioclasts (bones), non-phosphatic minerals, and cement. Geochemically, phosphorites contain high concentrations of P2O5 (23.59–28.36 wt.%) and CaO (40.85–44.35 wt.%), with low amounts of Al2O3 (0.23–0.51 wt.%), TiO2 (0.01–0.03 wt.%), Fe2O3 (1.14–2.28 wt.%), Na2O (0.37–1.19 wt.%), K2O (0.03–0.12 wt.%), and MnO (0.08–0.18 wt.%), suggesting the low contribution of the detrital material during their deposition. Moreover, they belong to contain enhanced U concentration (55–128 ppm). They are also enriched with Sr, Ba, Cr, V, and Zn and depleted in Th, Zr, and Rb, which strongly supports the low detrital input during the formation of the Hamadat phosphorites. The high Radioactivity of the studied phosphorites is probably due to the widespread occurrence of phosphatic components (e.g., apatite) that accommodate U in high concentrations. Gamma spectrometry based on NaI (Tl) crystal 3×3 has been used to measure occurring radionuclides in the phosphorite samples. The results indicate that the radioactive concentrations’ average values of 226Ra, 232Th, and 40K are 184.18±9.19, 125.82±6.29, and 63.82±3.19 Bq Kg-1, respectively. Additionally, evaluations have been made of the radiological hazards. The calculated risk indicators exceeded the recommended national and world averages. The data obtained will serve as a reference for follow-up studies to evaluate the effectiveness of the Radioactivity of phosphatic materials collected from the Hamdat mine area.

Vegetation Type Mapping in Southern Patagonia and Its Relationship with Ecosystem Services, Soil Carbon Stock, and Biodiversity

“…The main land use cover area estimates extracted from the map at the regional level identified about 142,085 km 2 of steppe grasslands (representing 58.1% of the total area), 38,355 km 2 of Mata Negra Matorral thicket (15.7%), and about 25,189 km 2 of bare soil (10.3%) (Table 1). The native forest VT represented 3728 km 2 (1.5%), where pure N. pumilio forest would cover about 2538 km 2 (1.0%) followed by pure N. antarctica forest, occupying 1000 km 2 (0.4%). Permanent water bodies and glaciers were mapped at 5428 (2.2%) and 3484 km 2 (1.4%), respectively.…”

“…The native forest VT represented 3728 km 2 (1.5%), where pure N. pumilio forest would cover about 2538 km 2 (1.0%) followed by pure N. antarctica forest, occupying 1000 km 2 (0.4%). Permanent water bodies and glaciers were mapped at 5428 (2.2%) and 3484 km 2 (1.4%), respectively. Table 2 shows the confusion matrix for land use classifications.…”

“…Planning and land management institutions need comprehensive information on the types of land-use cover to provide the basis for understanding the status, trends, and Sustainability 2024, 16, 2025. https://doi.org/10.3390/su16052025 https://www.mdpi.com/journal/sustainability pressures of human activity on natural resources, carbon cycles, and biodiversity [1,2]. From this, Vegetation Type (VT) mapping using Optical Earth observation (EO) data is essential for the management and conservation of natural resources, as well as for the evaluation of the supply of provisioning ecosystem services (ESs), the maintenance of ecosystem functions, and the conservation of biodiversity in anthropized environments [3][4][5].…”

Geochemical characteristics, hazards impact assessment and radiogenic heat production of the alkaline rocks

“…The primary source of natural radioactivity in rocks emanates from the presence of radionuclides (e.g., 238 U, 232 Th, and 40 K), which intricately linked to their mineralogical composition 1 , 2 . Amidst the growing public apprehension regarding radiation exposure, there has been a surge in studies focusing on high-background natural radiation areas.…”

“…The radioactive elements and rare earth elements (REEs) are mainly sourced from resources such as phosphorites 2 ; ironstone 14 ; black shale 15 , rare metal granites 8 ; pegmatites 16 , carbonatites and alkaline-rich rocks 17 among others. Notable areas for REEs include China (Bayan Obo deposit) 18 , Australia (Mount Weld deposit) 19 , and Brazil (Catalão deposit) 20 .…”