Uncontrolled urban waste dumps in low- and middle-income countries act as unregulated reservoirs for naturally occurring radioactive materials (NORM), posing potential radiation exposure risks to both humans and non-human biota. This study provides a high-resolution radiological characterization of five major dumpsites in Gusau, Nigeria (G1–G5). Activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in 60 soils, 60 plant, and 25 well water samples were determined using NaI(Tl) gamma spectrometry (relative uncertainty 1 (max 1.34), necessitating Tier 2 (Brown et al., 2022; Hosseini et al., 2024). Tier 2 refined assessment showed expected RQs for all reference organisms (plants, birds, mammals, reptiles) were 0.96, p < 0.01) identified ²³²Th as the dominant external dose driver, while ²²⁶Ra dominated internal food-chain risk. We conclude that while direct external human risk is low, enhanced ²²⁶Ra plant transfer creates a chronic internal exposure pathway requiring biomonitoring. The ERICA Tool successfully identified lichens as the critical ecological receptor, consistent with recent European recommendations.
Girigisu et al. (Sun,) studied this question.