Geochemical and Radiological Assessment of a Region with Phosphate Deposits, Democratic Republic of the Congo

Abstract

Four areas in the Kongo Central Province, western Democratic Republic of the Congo, with unexploited phosphate deposits were investigated to assess the composition of phosphatic materials and to evaluate pollution hazards, including radiological hazards arising from naturally occurring radionuclides. In those areas, phosphate rocks were sampled and analyzed for P2O5 content (by ED-XRF), and for the naturally occurring radionuclides 238U, 226Ra, 232Th, 40K (by gamma-ray spectrometry). Phosphate rocks displayed P2O5 content ranging from 1.06 to 24.42% (dry weight) and exceptionally high 238U and 226Ra activity concentrations (up to 3069 and 2273 Bq kg−1, respectively), significantly exceeding global averages in soils. Radiological hazard indices, including the radium equivalent (RaEq), annual effective dose and lifetime cancer risk, confirmed potential health risks associated with phosphate-rich rocks. With the upcoming development of phosphate deposits in DRC, such phosphate materials might become future sources of both geochemical contamination and radiological exposure, emphasizing the need for suitable radiation monitoring and waste management plans prior to and during mineral resource exploitation.