Concentration of Radiocesium in the Wild Japanese Monkey (Macaca fuscata) over the First 15 Months after the Fukushima Daiichi Nuclear Disaster

Abstract

Following the massive earthquake that struck eastern Japan on March 11, 2011, a nuclear reactor core meltdown occurred at the Fukushima Daiichi Nuclear Power Plant, operated by Tokyo Electric Power Company, and was followed by the release of large amounts of radioactive materials. The objective of this study was to measure the concentration of radiocesium 134Cs and 137Cs in the muscle of Japanese monkeys (Macaca fuscata) inhabiting the forest area of Fukushima City and to determine the change in concentration over time as well as the relationship with the level of soil contamination. Cesium concentrations in the muscle of monkeys captured at locations with 100,000–300,000 Bq/m2 were 6,000–25,000 Bq/kg in April 2011 and decreased over 3 months to around 1,000 Bq/kg. However, the concentration increased again to 2,000–3,000 Bq/kg in some animals during and after December 2011 before returning to 1,000 Bq/kg in April 2012, after which it remained relatively constant. This pattern of change in muscle radiocesium concentration was similar to that of the change in radiocesium concentration in atmospheric fallout. Moreover, the monkeys feed on winter buds and the cambium layer of tree bark potentially containing higher concentrations of radiocesium than that in the diet during the rest of the year. The muscle radiocesium concentration in the monkeys related significantly with the level of soil contamination at the capture locations.

Low blood cell counts in wild Japanese monkeys after the Fukushima Daiichi nuclear disaster

“…The Japanese monkey usually forms a troop of 50–100 individuals of maternal lineage, and each troop has a home range of about 8–31 km 2 in snowy areas6. The mean muscle radiocesium concentration in monkeys captured in areas with a soil contamination level of 100,000–300,000 Bq/m 2 was significantly higher than that in monkeys captured in areas of 10,000–100,000 Bq/m 2 (P < 0.001)5.…”

“…Between April 2011 and June 2012, Hayama et al 5 investigated chronological changes in muscle radiocesium concentrations in monkeys inhabiting Fukushima City. The Japanese monkey usually forms a troop of 50–100 individuals of maternal lineage, and each troop has a home range of about 8–31 km 2 in snowy areas6.…”

The biological impacts of ingested radioactive materials on the pale grass blue butterfly

“…The accumulation of radionuclides in the bodies of wild and domesticated organisms and in agricultural products has also been documented4567891011. However, the biological impacts of this pollution on the health and disease of wild organisms have not been examined sufficiently.…”

Contamination of Wild Animals: Microhabitat Heterogeneity and Ecological Factors of Radioactive Cesium Exposure in Fukushima

“…Unfortunately, there is very little information on the wildlife in the contaminated area of Abukuma Mountains before the F1NPP accident. It will be desirable to monitor the ecosystem and several principal wildlife species, such as some of the dominant 10 birds (explained previously), S. scrofa and unique primate Macaca fuscata (Hayama et al 2013), until most of the ecosystems and human societies regain stability in five or more decades later (Galvan et al 2014).…”