Effects of 137Cs contamination after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident on food and habitat of wild boar in Fukushima Prefecture.

After the Tokyo Electric Power Company Fukushima Dai-ichi Nuclear Power Station accident, wild boar was found to have greater radiocesium (137Cs) activity concentrations in their bodies than other wild animals in Japan; however, the reason for this remains unknown. To understand the mechanism of 137Cs transfer from the environment to wild boar, and the factors that affect variation in 137Cs contamination in wild boar, we sampled muscle and stomach contents from wild boar captured in Fukushima Prefecture and analyzed the relationships among 137Cs concentrations in muscle tissue and in the stomach contents, 137Cs ground deposition at capture sites, and wild boar food habits. Significant positive relationships were observed among 137Cs activity concentrations in muscle and stomach contents, as well as 137Cs deposition density at capture sites. These results suggest that 137Cs is transferred from the environment to plant and animal materials consumed by wild boar, and then from these foods to the bodies of wild boar through digestion. However, no correlation was observed between 137Cs concentrations in stomach contents and the presence of any particular food item in stomachs of wild boar, including mushrooms. These findings suggest mushrooms and underground food items, which were found to affect 137Cs concentrations in wild animals in Europe, were not important contributors to high levels of 137Cs contamination in Japanese wild animals.