Dataset Information

Decadal trends in ¹³⁷Cs concentrations in the bark and wood of trees contaminated by the Fukushima nuclear accident.

ABSTRACT: Understanding the actual situation of radiocesium (¹³⁷Cs) contamination of trees caused by the Fukushima nuclear accident is essential for predicting the future contamination of wood. Particularly important is determining whether the ¹³⁷Cs dynamics within forests and trees have reached apparent steady state. We conducted a monitoring survey of four major tree species (Japanese cedar, Japanese cypress, konara oak, and Japanese red pine) at multiple sites. Using a dynamic linear model, we analyzed the temporal trends in ¹³⁷Cs activity concentrations in the bark (whole), outer bark, inner bark, wood (whole), sapwood, and heartwood during the 2011-2020 period. The activity concentrations were decay-corrected to September 1, 2020, to exclude the decrease due to the radioactive decay. The ¹³⁷Cs concentrations in the whole and outer bark samples showed an exponential decrease in most plots but a flat trend in one plot, where ¹³⁷Cs root uptake is considered to be high. The ¹³⁷Cs concentration ratio (CR) of inner bark/sapwood showed a flat trend but the CR of heartwood/sapwood increased in many plots, indicating that the ¹³⁷Cs dynamics reached apparent steady state within one year in the biologically active parts (inner bark and sapwood) and after several to more than 10 years in the inactive part (heartwood). The ¹³⁷Cs concentration in the whole wood showed an increasing trend in six plots. In four of these plots, the increasing trend shifted to a flat or decreasing trend. Overall, the results show that the ¹³⁷Cs dynamics within forests and trees have reached apparent steady state in many plots, although the amount of ¹³⁷Cs root uptake in some plots is possibly still increasing 10 years after the accident. Clarifying the mechanisms and key factors determining the amount of ¹³⁷Cs root uptake will be crucial for predicting wood contamination.

SUBMITTER: Ohashi S

PROVIDER: S-EPMC9253084 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Contamination of freshwater fishes with 137Cs remains as a serious problem in Japan, nearly 10 years after the Fukushima nuclear power plant accident, but there is limited information on the distribution of 137Cs contamination in fish bodies. The 137Cs distribution can be used for the estimation of internal radiation exposure through the consumption of fish and for the dose estimation of fish themselves. In this study, the 137Cs distribution in the bodies of 8 freshwater fish species was investigated as percentages of total body burden for fish inhabiting Lake Inba. Fish samples were caught in stake nets placed close to the shore approximately once a month. After the measurement of body length and fresh weight, the radioactivities of 137Cs in muscle, internal organs, spawn, milt and bone were assayed using high-purity germanium detectors. Analysis of all fish samples showed that the 137Cs distribution was highest in muscle (54 ± 12%), followed by internal organs (7.8 ± 4.6%), spawn (7.4 ± 5.4%), milt (3.2 ± 2.1%) and bone (1.2 ± 0.58%). Among fish species, the highest proportion of 137Cs in muscle was detected in largemouth bass (71 ± 1 3%), followed by snakehead (69 ± 14%), channel catfish (63 ± 17%), common carp (62 ± 14%), barbel steed (58 ± 6.5%), silver carp (57 ± 7.7%), bluegill (53 ± 4.7%), and crucian carp (50 ± 10%). These results suggested that the 137Cs in muscle was likely to be high in piscivorous fishes compared to omnivorous fishes, especially crucian carp. The proportion of 137Cs in muscle of crucian carp was not explained either by body length or fresh weight. However, a positive correlation was found between the proportion of 137Cs in muscle and the condition factor which was an indicator of nutritional status calculated from a length-weight relationship. This correlation implied that more 137Cs accumulated in muscle tissue of a fish species with high nutritional status. This is the first study to show that condition factor is more important than body length and wet weight in explaining the high proportion of 137Cs in muscle tissues, at least for crucian carp.

Dataset Information

Decadal trends in ¹³⁷Cs concentrations in the bark and wood of trees contaminated by the Fukushima nuclear accident.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Decadal trends in 137Cs concentrations in the bark and wood of trees contaminated by the Fukushima nuclear accident.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Decadal trends in ¹³⁷Cs concentrations in the bark and wood of trees contaminated by the Fukushima nuclear accident.