Assessment of natural radioactivity in soil, rocks, and water along the Manali-Leh Highway, India

Natural background radiation has been an inevitable part of living beings since the evolution of the earth. The measurement of natural radioactivity is of great importance in health physics as well as environmental and geological formation studies. The natural radioactivity in 50 soil, 50 rock, and 31 water samples collected from the Upper Himalayas region along the Manali-Leh Highway is measured in the present study. Uranium and other heavy metals are measured in water samples using LED Fluorimeter and AAS techniques. The concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K in rock and soil samples is measured using an HPGe detector. The elemental analysis of rock samples is also carried out using the SEM-EDS technique. The average uranium concentration in water samples is found to have a value of 4.71 μg L^-1. The overall average of uranium and other heavy metals in water have concentrations within the safe limits. The average activity of primordial radionuclides for rock and soil samples is within the world average values. The activity of these primordial radionuclides in soil and rocks differs considerably. Also, after a particular location, a significant decrease in radioactivity concentration in rocks and soil is observed, due to the different geological and topological formations present in the region. (author)