Correspondence on “Fukushima Contaminated Water Risk Factor: Global Implications”

Recommendations W e recognize the efforts of Liu et al. 1 in bringing attention to the global issue of ocean protection, which is a shared priority, particularly in the context of Japan's discharge of advanced liquid processing system (ALPS)-treated water into the North Pacific Ocean. 2 Their effort to evaluate the potential impacts of the upper-activity-limit annual release of 22 TBq of tritium ( 3 H) from the Fukushima Daiichi Nuclear Power Plant (FDNPP) reflects the scientific community's commitment to transparency and environmental stewardship.However, we are concerned that the paper overstated the associated risks by relying on unconventional and misleading metrics and by omitting essential scientific context.Several aspects of their analysis could benefit from additional context to ensure that risk evaluations are aligned with internationally accepted standards.In particular, some of the metrics and assumptions used in Liu et al. have led to an overestimation of potential impacts.The 3 H releases are closely assessed and monitored under international frameworks.The amount of 3 H released from the FDNPP was smaller than the routine, permitted discharges from many operating nuclear facilities in Asia and worldwide.Available monitoring data and dose assessments, including those undertaken by the IAEA, 3,4 indicate that even when considering organically bound tritium (OBT) formation, expected doses to humans and marine organisms remain far below levels associated with any measurable health or ecological effects.While we recognize that physical and biological processes and its chemical form may affect 3 H behavior in the environment, whatever processes are influencing 3 H in the Pacific have not led to biota concentrations that cause concern.It represents an insignificant addition to the 3 H concentration in the Pacific Ocean, far below natural background concentration variability.In addition, the source term for cesium-137 ( 137 Cs) used in their risk assessment results is substantially inconsistent with independently verified data, which affects the resulting conclusion.Below, we highlight the specific metrics used by Liu et al. 1 that could result in spurious conclusions, and we provide needed scientific context to better illuminate any potential environmental risks.