VISAKHAPATNAM: Beach sand samples collected along the Visakhapatnam coast contain concentrations of naturally occurring radioactive elements above global average levels, with relatively higher concentrations recorded in the northern sector of the study area, according to a research paper published by Springer Nature.
The study, titled ‘Spatial distribution of natural radionuclides and radiological hazard assessment in beach sands of the Visakhapatnam coast, Eastern India’, examined four naturally occurring radionuclides, including uranium-238, radium-226, thorium-232 and potassium-40, and assessed their distribution in beach sands, and the associated ambient radiation levels.
The paper was authored by B Ramesh, P Padma Savitri, J Sudhakar, R Balaram Kumar, SK Sahoo, IV Saradhi and Vandana Pulhani.
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The authors are associated with the Environmental Monitoring and Assessment Division of the Bhabha Atomic Research Centre (BARC) in Visakhapatnam, Andhra University, and the Homi Bhabha National Institute in Mumbai.
The researchers recorded mean activity concentrations of 167 becquerels per kilogram (Bq/kg) for uranium-238, 292 Bq/kg for radium-226, 2,614 Bq/kg for thorium-232 and 449 Bq/kg for potassium-40. The concentrations varied considerably between sampling locations, particularly in the case of thorium-232, which ranged from 6.9 to 13,691.7 Bq/kg.
The findings point to a marked variation in the distribution of natural radioactivity along the coastline. The researchers observed relatively higher concentrations in the northern part of the study area, while samples collected across different sections of the beach also showed variations in radioactivity.
The measurements were carried out using a high-purity germanium (HPGe)-based gamma spectrometry system, which is used to identify and quantify radioactive elements in samples. The researchers also generated spatial distribution maps to examine the pattern of radionuclide concentrations.
The study found that activity concentrations at some locations exceeded global average values. The measured absorbed gamma dose rates were comparable to those reported in monazite-rich high background radiation areas in India, and other parts of the world.
The researchers, however, noted variations in the concentrations across the study area, underscoring the need to consider local differences when assessing natural radioactivity along the coastline.