Figure 1: Fukushima nuclear power plant (NBC, 2021)

Radionuclide water pollution occurs though multiple sources, from natural processes like the decomposition of rocks containing high concentrations of radionuclide, to anthropogenic sources like uranium mining (Tsivoglou & Towne, 1957). With the rise of nuclear energy, wastewater from nuclear power plant accidents are the main sources of aquatic radionuclide pollution today (Martinez et al., 2021). A recent example would be the 2011 Fukushima nuclear disaster (Fig.1), where there was a direct discharge of leaked radioactive cooling water from the reactor into the ocean, which led to the doubling of radioactive caesium in the north Pacific Ocean (Nakajima et al., 2019).

Effects of aquatic radionuclide pollution

The influx of radioactive caesium into seawater would subsequently be incorporated into marine life through seawater uptake and food ingestion (Morita et al., 2019). A study conducted by Horiguchi et al. (2019) suggests that the Fukushima disaster had led to the reduction in population density, species richness and biomass of aquatic wildlife off the coasts of the nuclear plant. These effects were partly attributed to the production of gamma rays from the decay of radionuclides. These penetrative gamma rays are known to damage tissue and DNA, causing the mortality of eggs and larvae of fish while also reducing the fertility of adult organisms (ICRP, 2008).

Additionally, the release of radionuclides into the atmosphere during the Fukushima incident had seen its transportation and deposition into freshwater systems. The rivers of the Abukuma Mountains area, located further inland, are currently experiencing a trend of recovery from radionuclide pollution (Igarashio et al., 2022). According to Yusof et al. (2019), the prolonged exposure of salmon to radionuclide in the Mano River in Abukuma mountains has led to genetic mutations, with alterations in the amino acid substitutions within newer generations of salmon. While it still remains unknown how these mutations affect the salmon, these findings highlight the biological legacy of the Fukushima incident, which could affect ecosystems in the long run.

The Fukushima nuclear meltdown in 2011 following the Tohuku earthquake was an unforeseen and unfortunate event. Although more than a decade has passed since the disaster, the region still struggles with recovery, with residents gradually returning in 2022 (Jozuka & Regan, 2022). Scars on the city still remain and it may be some time before these physical and psychological wounds heal.

References:

Horiguchi, T., Kodama, K., Kume, G., & Kang, I. J. (2019). Delayed recovery from declines in the population densities and species richness of intertidal invertebrates near Fukushima Daiichi Nuclear Power Plant. Low-Dose Radiation Effects on Animals and Ecosystems, 65–88. https://doi.org/10.1007/978-981-13-8218-5_6

Igarashi, Y., Nanba, K., Wada, T., Wakiyama, Y., Onda, Y., Moritaka, S., & Konoplev, A. (2022). Factors controlling the dissolved 137 cs seasonal fluctuations in the Abukuma River under the influence of the Fukushima Nuclear Power Plant Accident. Journal of Geophysical Research: Biogeosciences, 127(1). https://doi.org/10.1029/2021jg006591

International Commission on Radiological Protection (ICRP) (2008) Environmental protection – the concept and use of reference animals and plants. ICRP Publication 108. Ann ICRP 38:4–6. Retrieved from: https://www.icrp.org/publication.asp?id=icrp%20publication%20108

Jozuka, E. & Regan, H. (2022, June 14). ‘We’re still recovering’: 11 years after Fukushima nuclear disaster, residents return to their village. CNN. Retrieved from: https://edition.cnn.com/2022/06/14/asia/japan-fukushima-katsurao-village-return-intl-hnk/index.html

Martinez, G., Restrepo-Baena, O. J., & Veiga, M. M. (2021). The myth of gravity concentration to eliminate mercury use in artisanal gold mining. The Extractive Industries and Society, 8(1), 477–485. https://doi.org/10.1016/j.exis.2021.01.002

Morita, T., Ambe, D., Miki, S., Kaeriyama, H., & Shigenobu, Y. (2019). Impacts of the Fukushima nuclear accident on fishery products and fishing industry. Low-Dose Radiation Effects on Animals and Ecosystems, 31–41. https://doi.org/10.1007/978-981-13-8218-5_3

Nakajima, T., Ohara, T., Uematsu, M., & Onda, Y. (2019). Environmental Contamination from the Fukushima Nuclear Disaster, 5–49. Cambridge University Press. https://doi.org/10.1017/9781108574273.003

NBC. (2021, August 26). Fukushima nuclear plant water to be released into the ocean via undersea tunnel. NBC. Retrieved from: https://www.nbcnews.com/news/world/fukushima-nuclear-plant-water-be-released-undersea-tunnel-n1277630

Tsivoglou, E. C., & Towne, W. W. (1957). Sources and Control of Radioactive Water Pollutants. Sewage and Industrial Wastes, 29(2), 143–156.

Yusof, M. F., Kawada, G., Enomoto, M., Tomiya, A., Watanabe, M., Morishita, D., Izumi, S., & Nakajima, M. (2019). Mutations observed in mitochondrial DNA of salmon collected in Mano River, Fukushima Prefecture, Japan. Low-Dose Radiation Effects on Animals and Ecosystems, 89–98. https://doi.org/10.1007/978-981-13-8218-5_7