Radioactive contamination of aquatic insects in a stream impacted by the Fukushima nuclear power plant accident

The Fukushima Daiichi Nuclear Power Plant accident emitted radioactive substances into the environment, contaminating a diverse range of organisms. Stream algae, litter, sand substrate, aquatic insects and fishes are among the organisms that have been impacted. Radioactive Cs contaminations in the litter and sand substrate were elevated where the atmospheric dose rate in the air was high. Radioactive Cs contaminations in algae and aquatic insects varied irregularly; nevertheless, radioactive Cs contaminations in aquatic insects in pools were consistently higher than those in stream riffles. Contamination by the radioactive Cs differed by species, location and stream velocity. This study was undertaken in a limited number of samples and sites, with more extensive studies planned to fully determine the impact of radionuclides on aquatic ecosystems.