Carbon-14 in the environment near the Belarusian and the Ignalina nuclear power plants in 2016–2025

Abstract

Carbon-14 ( ¹ ⁴C) is a critical radionuclide for environmental monitoring around nuclear facilities due to its high mobility, atmospheric prevalence, and incorporation into the biosphere via photosynthesis. This study presents the results of a ¹ ⁴C monitoring (2016–2025) in terrestrial and aquatic ecosystems within the vicinities of two nuclear power plants situated 98 km apart: the newly commissioned Belarusian NPP (BelNPP) and the Ignalina NPP (INPP), which has been undergoing decommissioning since 2010. Analyses were performed on biota (terrestrial and aquatic) and dissolved inorganic carbon (DIC) in water. The findings reveal a distinct contrast in ¹ ⁴C distribution. In terrestrial ecosystems, no significant excess was detected at the outer boundary of the 30-km zones. However, a residual ¹ ⁴C excess (up to 7.7 ± 2.5 pMC) was measured in the immediate vicinity (0–5 km) of the decommissioned INPP, 15 years after its shutdown. In contrast, aquatic ecosystems—in particular the Neris River (BelNPP) and Lake Drūkšiai (INPP)—showed variable but significant ¹ ⁴C excess (approx. 540 pMC in DIC of the Neris River, and approx. 394 pMC in aquatic biota of Lake Drūkšiai), unequivocally originating from the respective NPPs. A key outcome of this research is the demonstration of prolonged ¹ ⁴C persistence in the environment after reactor shutdown, underscoring the necessity for long-term environmental monitoring throughout the entire lifecycle of nuclear facilities.