Assessment of the Radiological Impacts of Radionuclides in Soil Samples of Flood Ravaged Areas in Isoko North and South LGA, Delta State, Nigeria

Abstract

This dissertation investigates the impact of natural radioactivity in soil samples
collected from flood-affected areas in the Isoko North and South Local
Government Areas (LGAs) of Delta State, Nigeria. The aim was to identify
potential radiological health risks in these areas, where periodic flooding may
affect the distribution of naturally occurring radioactive elements.
Gamma spectrometry detectors were used to examine soil samples from both
flood-damaged and non-flooded control points in order to quantify the activity
concentrations of radionuclides 238U, 232Th, and 40K. The analysis found that
the average activity concentrations of 238U ranged from 25.67 Bqkg⁻¹ in floodprone
areas to 8.13 ± 1.73 Bqkg⁻¹ in control zones. The concentrations of 232Th
and 40K also varied, with notable ranges in flood-exposed areas compared to
control samples, highlighting an increase potentially linked to flood dynamics.
Radiological hazard indices, such as the Absorbed Dose Rate (ADR), Annual
Effective Dose Equivalent (AEDE), and Excess Lifetime Cancer Risk (ELCR),
were calculated. ADR values ranged from 14.58 nGyh⁻¹ to 26.98 nGyh⁻¹, while
AEDE values averaged 25.20 μSvy⁻¹, both well below UNSCEAR's recommended
safety thresholds. The study reveals that flooding alters soil radionuclide
distribution, with most areas remaining within safe radiation limits. However,
elevated 238U levels in some flood-prone sites exceed WHO thresholds,
highlighting the need for continued monitoring and assessment of potential risks.
This research concludes by suggesting that Isoko North and Isoko South LGAs
conduct periodic evaluations to track potential cumulative effects on public health
and the environment, thereby providing crucial data to guide future
environmental safety and public health efforts in flood-affected areas.