Exploring the Correlation between Primordial Radionuclides and Heavy Metal Concentrations in Surface Environmental Media of the Dhaka Region, Bangladesh

Abstract

Rapid urbanization and industrial expansion in the Dhaka District of Bangladesh have led to significant soil contamination from heavy metals and naturally occurring radionuclides, posing increasing risks to environmental quality and human health. This study synthesizes published research on the correlation between primordial radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) and heavy metals (Pb, As, Zn, Mn, Cd, Fe, Cu, Cr) in soils, dust, and plants from industrial and rural areas in Dhaka District, Bangladesh. Data sources of Savar, Ashulia, and DEPZ were integrated to calculate radiological indices (Raeq, D, AEDE, AGDE, Iγ, Hex, and Hin) and contamination indices (CF, EF, Igeo, and PLI) for assessing environmental and health risks. Mean activities of ²²⁶Ra, ²³²Th, and ⁴⁰K exceed the global reference values, especially in industrial zones, but their Raeq and related hazard indices remain within international limits. However, the rate of absorbed dose (D), AEDE, and, more importantly, AGDE, approximately two times higher than the world average in industrial (601.93 ± 100.72 µSv/yr) and rural (503.43 µSv/yr) locations, provides a warning of radiological concern. Anthropogenic contamination of industrial soils is characterized by enrichment of Pb, Zn, Cd, Cu, and Cr (PLI > 1). Correlation analysis reveals mostly weak or negative relationships between most radionuclides, meaning that the levels of each radionuclide are regulated by the geological background and certain anthropogenic additions instead of direct correlations with heavy metals.