Researchers investigated the long-term contamination of Lake Onuma in Japan resulting from the 2011 Fukushima Daiichi nuclear disaster. They devised a formula based on a framework known as the fractional diffusion model to predict the radioactive contamination of the lake for up to about 30 years after the Fukushima accident. The results suggest that the decrease in radioactivity concentration will be slower than predicted by the conventional two-component decay function model.