First study on 236U in environmental samples from Bangladesh by ICP-MS/MS prior to the operation of its first nuclear power plant

For the first time, using ICP-MS/MS, the 234U, 235U, 236U, and 238U in the sediment samples from coastal region, Bangladesh, were measured as 5.13–5.48, 0.234–0.252, (2.70–4.59) × 10–5, and 4.92–5.31 Bq kg−1, and the 236U/238U atom ratios were (2.87–4.57) × 10–8, indicating the predominate influence of global fallout on 236U. For the rock samples from hilly area, the corresponding concentrations were much higher as 18.7–4023, 0.902–173, 9.58 × 10–5–1.29 × 10–2, and 18.8–2279 Bq kg−1, but the 236U/238U atom ratios were in the same range of (1.52–3.04) × 10–8, indicating the 236U was primarily due to the natural nuclear reactions.