Cumulative effects of radioactivity from
Fukushima on the abundance andbiodiversity of birds
A. P. Møller, I. Nishiumi &T. A. Mousseau

Journal of Ornithology
ISSN 2193-7192
J Ornithol
DOI 10.1007/s10336-015-1197-2

1 23

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Author's personal copy
J Ornithol
DOI 10.1007/s10336-015-1197-2

REVIEW

Cumulative effects of radioactivity from Fukushimaon the abundance and biodiversity of birds
A. P. Møller1 • I. Nishiumi2 • T. A. Mousseau3,4Received: 18 October 2014 / Revised: 3 March 2015 / Accepted: 3 March 2015
Ó Dt. Ornithologen-Gesellschaft e.V. 2015

Abstract Species differ in their susceptibility to radiation because of differences in their ability to sustain
toxic and genetic effects caused by radiation. We censused breeding birds in Fukushima Prefecture, Japan,
during 2011-2014 to test whether the abundance and diversity of birds became increasingly negatively affectedby radiation over time. The abundance of birds decreased
with increasing levels of background radiation, with significant interspecific variation. Even though levels of
background radiation decreased over time, the relationshipbetween abundance and radiation became more negative

Communicated by E. Matthysen.

Electronic supplementary material The online version of thisarticle (doi:10.1007/s10336-015-1197-2) contains supplementarymaterial, which is available to authorized users.
& A. P. Møller
anders.moller@u-psud.fr
I. Nishiumi
nishiumi@kahaku.go.jp
T. A. Mousseau
mousseau@sc.edu
1Laboratoire d’Ecologie, Systématique et Evolution, CNRSUMR 8079, Université Paris-Sud, Bâtiment 362,
91405 Orsay Cedex, France

2

Department of Zoology, National Museum of Nature andScience, 3-23-1 Haykunin-cho, Shinjuku-ku,
Tokyo 169-0073, Japan3

Department of Biological Sciences, University of South
Carolina, Columbia, SC 29208, USA

4

Department of Environmental Biology, Biosciences, andBiotechnology, Chubu University, Kasugai, Aichi 487-8501,
Japan

over time. The relationship between abundance andradiation became less negative with increasing trophic
levels. These findings are consistent with the hypothesisthat the negative effects of radiation on abundance andspecies richness accumulate over time.
Keywords
resistance

Birds  Chernobyl  Fukushima  Radiation

Introduction
Radiation has been demonstrated to have diverse negative effects on animals and plants under natural conditions (Møller and Mousseau 2011b). There are highly
radiation-resistant bacteria and fungi that are able tocope with extreme natural levels of radiation (Dadachova et al. 2004; Daly 2009), but such organisms seemto be exceptions rather than the rule. While naturallevels of radiation vary worldwide with significant effects on the incidence of disease in humans (e.g., Lubin
and Boice 1997; Hendry et al. 2009), and by implication
also on other organisms (Møller and Mousseau 2011b),
there are significant radiation effects involving DNA
damage and mutations (e.g., Ghiassi-Nejad et al. 2004),
following the original observation that radiation is a
powerful mutagen (Nadson and Philippov 1925). Recently, interest in the effects of low-dose radiation on
public health but also on free-living organisms has been
increasing following the nuclear accidents at Chernobyl
and Fukushima.
Acute exposure to radiation has negative effects on anumber of physiological processes such as oxidative stressand immune function, while chronic exposure across extended periods of time can result in severe accumulations

123

Author's personal copy
J Ornitholof effects of mutations during the lifespan of individuals,
but also across generations. Current studies, generally
conducted under laboratory conditions, typically rely on
acute exposure, while the chronic effects of extended exposure are rarely considered. We previously showed thatthe abundance and diversity of birds and other organisms at
Chernobyl were more strongly negatively impacted by agiven level of radiation than those affected by similarlevels of exposure at Fukushima (Møller et al. 2012). Thus,
the difference in the actual levels of radiation in Chernobyl
and Fukushima is not the cause since the effects were
quantified as effects per unit of background radiation.
Some studies suggested that the negative impact of radiation may become ameliorated over time because ofadaptation in terms of improved DNA repair (Boubriak
et al. 2008). The stronger negative effects at Chernobyl
than at Fukushima that we previously documented (Møller
et al. 2012) may be associated with a longer history of
exposure, although alternative explanations such as differences in radionuclides and their toxicity may also play arole.
Here we report the results of analyses of unique data on
the abundance of breeding birds in Fukushima, Japan, in
relation to the background level of radiation during the
2011–2014 period. This period covers the radiation effects
just after the Fukushima accident, but also the subsequentchronic effects accumulated during the following 3 years.
This is the first study quantifying such cumulative temporal
effects of radiation over time.
The objectives of this study were to test (1) whether
the effect of radiation reduced the abundance and species
richness of birds, (2) whether this effect differed among
species, and (3) whether such negative effects of radiation accumulated over time. Ionizing radiation at
Chernobyl and Fukushima had negative effects on theabundance and species richness of birds and other organisms (Møller and Mousseau 2007a, b; Møller et al.
2011a, b, 2012). Such effects vary considerably among
species because of differences in the physiology andecology (Møller and Mousseau 2007b; Galván et al.
2011, 2014). Unfortunately, there are no population
studies or studies of a broad range of species dating backto the period prior to the accidents at Chernobyl in 1986
or Fukushima in 2011. We conducted the first standardized counts of breeding birds in 2006 in Chernobyl,
20 years after the accident. We started bird counts inFukushima already in 2011, allowing for tests of effectsof ionizing radiation directly from the start of radiation
exposure. Here we present analyses of these unique dataon the effects of radiation since 2011 at Fukushima in an
attempt to determine whether such negative effects ofradiation on the abundance and diversity of birds accumulate over time.

123

Fig. 1 Location of census areas around Fukushima, Japan, indicatedby lines of dark blue dots in relation to the background radiationlevel. Circles show distances of 5 and 50 km from the reactors.
Radiation level increases from the lowest level for light blue to thehighest level for the darkest shade of red. Adapted from http://www.
nnistar.com/gmap/fukushima, generated by the Japanese Ministry of
Education, Culture, Sports, Science and Technology (MEXT) andlocal government (color figure online)

Methods
Study sites
We conducted breeding bird censuses at a total of 400
sampling points (in 2011 only 300 points) in forested areas
around the Fukushima Daiichi power plants in 2011–2014,
totaling 1,500 sampling events (Fig. 1). At least one local
ornithologist (Satoe Kasahara, Shin Matsui, Isao Nishiumi
or Keisuke Ueda) participated in approximately a quarterof the censuses in Japan to confirm the identity of somedifficult bird species. However, all analyses presented here
were based on the data recorded by APM. All samplingsites were localized using GPS coordinates, and altitude
was estimated to the nearest foot using a GPS.
Census methods
The point count census method provides reliable information on the relative abundance of birds (Blondel et al. 1970;
Møller 1983; Bibby et al. 2005; Vořı́šek et al. 2010). Thismethod has provided highly repeatable results for birds andother animals at Chernobyl (Møller and Mousseau 2011a).
It consists of counts lasting 5 min during which the numberof birds seen or heard is recorded. Each census point was
separated from the previous point by a minimum distance of
100 m. In Fukushima APM with the help of IN conducted
these standard point counts on 11–15 July 2011, 14–19 July
2012, 14–19 July 2013 and 11–16 July 2014. The fact thatone person made all counts analyzed here eliminates any
variance in results due to interobserver variability.

Author's personal copy
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We directly tested the reliability of our counts by letting
two persons independently perform counts, and the degreeof consistency was high for both species richness andabundance (details reported by Møller and Mousseau
2007a). The Pearson product-moment correlation between
species richness in two series of counts conducted by two
different persons was r = 0.99, t = 42.06, df = 8,
P \ 0.0001, and for abundance it was equally high at
r = 0.99, t = 12.47, df = 8, P \ 0.0001.
Abundance estimates can be affected by numerous
confounding variables (Vořı́šek et al. 2010); therefore, it isimportant to control such variables statistically to assessthe underlying relationship between radiation and species
richness and abundance. We classified habitats in the field
directly at the census points immediately following the
5-min count [agricultural habitats with grassland or shrubs(either currently or previously cultivated), deciduous forest
or coniferous forest] and estimated to the nearest 10 %ground coverage by herbs, shrubs, trees, agricultural
habitat, deciduous forest and coniferous forest within adistance of 50 m from the census points. Weather conditions can affect animal activity and hence census results(Vořı́šek et al. 2010), and we recorded cloud cover at thestart of each point count (to the nearest eighth), temperature (degrees Celsius) and wind force (Beaufort). For
each census point, we recorded the time of day when the
count was started (to the nearest minute). Our bird counts
were concentrated in the morning with counts extending
across the entire day depending on other research activities.
Because bird activity may show a curvilinear relationshipwith time of day, for example, with high levels of activity
in the morning and to a lesser extent in the evening forbirds (Vořı́šek et al. 2010), we also included time squared
as an explanatory variable in the statistical analyses.
Background radiation
Radiation measurements at Fukushima were obtained using
the same dosimeters (model: Inspector, SE International,
Inc., Summertown, TN, USA) cross-validated with readings from a dosimeter that had been calibrated and certified
to be accurate by the factory during the weeks preceding
the study (International Medcom, Sebastopol, CA, USA).
All radiation measurements were made at the census points
immediately after each bird count. We also made a crossvalidation test by comparing our own measurements using
the Inspector dosimeter with measurements obtained at thesame locations with a TCS 171-ALOKA used by Japanese
authorities. There was a very strong positive relationship[linear regression on log-log transformed data:
F = 2427.97, df = 1, 20, r2 = 0.99, P \ 0.0001, slope(SE) = 1.120 (0.023)]. All data are reported in Electronic
Supplementary Material Table S1.

Diet
We scored the species as herbivores if they mainly fed on
foliage or seeds, primary consumers if they mainly fed on
insects, spiders and other invertebrates, and as top consumers if they mainly fed on vertebrates, relying on information presented in del Hoyo et al. (1992–2011).
Statistical analyses
Radiation levels were log10 transformed, and coverage with
agricultural land, herbs, shrubs and trees, deciduous forest,
coniferous forest and cloud cover was square-root arcsine
transformed before analyses.
We quantified the relationship between the abundance ofdifferent bird species and level of radiation by estimating
the slope of the relationship between abundance and log10transformed radiation while including potentially confounding variables in the statistical models (coverage by
herbs, shrubs, trees, agricultural habitat, deciduous forestand coniferous forest, altitude, cloud cover, temperature,
wind force, time of day and time of day squared). The
resulting species-specific partial slopes for bird abundancewith radiation were used for subsequent analyses. Thisapproach is extremely conservative because it reduces thetotal counts of the entire study to a single estimate per
species or in some analyses a single estimate per species
and year. We quantified species richness as the total
number of species recorded at a given observation point
under the assumption that such estimates would be distributed randomly across radiation levels if there were no
negative effects of radiation on species richness.
A common underlying assumption of most statisticalanalyses is that each data point provides equally precise
information about the deterministic part of total process
variation, i.e., the standard deviation of the error term isconstant over all values of the predictor variable(s) (Sokal
and Rohlf 1995). Because estimates of slopes depend on
sample sizes, and because sample sizes vary considerably
among species, this can have serious consequences forconclusions (Garamszegi and Møller 2010, 2011). The
standard solution to violations of this assumption is to weigheach observation by sampling effort in order to use all data,by giving each datum a weight that reflects its degree ofprecision due to sampling effort (Draper and Smith 1981;
Neter et al. 1996; Garamszegi and Møller 2010). Therefore,
we weighted statistical models by sample size in order to use
all data in relation to the precision of the estimates. Even asingle observation of a species was included in the analyses
because such an observation could theoretically be recordedat any of the observation points with a single point having anobservation of 1 and all other points an observation of 0. The
null hypothesis is that the slope in this case will be zero,123Author's personal copy
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while non-random locations of observations will be concentrated at low radiation levels if radiation has a negative
effect on the presence and the abundance of birds.
We tested whether the abundance of species was related
to the level of radiation, species and the interaction between radiation and species. Next we tested whether there
was a temporal trend in slope of the relationship between
abundance and background radiation under the predictionthat the extent of negative effects would accumulate acrossyears. Finally, we tested whether the slope of the relationship between abundance and radiation differed among
categories of main diet: herbivory or carnivory, or herbivores, primary consumers or top consumers. All standard
least squares analyses or in case of data that were notnormally distributed non-parametric tests were made with
JMP (SAS 2012).

of background radiation, and this decrease differed among
species as reflected by the significant species by radiationinteraction (Table 1). There was a strong negative relationship between species richness and radiation levelacross the census points (Fig. 3A; F = 6.73, df = 1, 1495,
P \ 0.0001), and there was an equally strong negative
relationship between the total number of individuals andradiation level across the census points (Fig. 3b;
F = 18.11, df = 1, 1495, P \ 0.0001).
The slope of the relationship between abundance andbackground radiation for 57 different species of birds
ranged from -0.525 to ?0.107, mean (SE) = -0.162(0.023) (Table 2). The mean slope differed significantly
from zero in an analysis weighted by sample size (onesample t-test, t = -7.16, df = 56, P \ 0.0001). This implies that species were on average less abundant at highlevels of radiation.

Results

Differences in slopes among years

Tests for interspecific differences in the effectof radiation on abundance

Correlation coefficients between abundance and radiationdiffered among years in an analysis weighted by sample
size (Fig. 4; F = 5.25, df = 3, 107, r2 = 0.05, P =0.0020) in a model that accounted for species (F = 73.17,
df = 56, 107, P \ 0.0001).
We compared the slope of the relationship between
abundance and radiation for the same species in different
years under the assumption that the relationship for slopesof different species in subsequent years should be positive
with a slope of one. Any deviation from this null expectation would imply that factors other than statistical dependence were involved. There was a significant change inslope across years with 57 species for which there weredata for at least 3 years (Kendall s = -0.192, SE = 0.074,
P = 0.012). While the relationship between abundance andbackground radiation on average was weakly negative in
2011, it became on average more strongly negative in 2012
(Fig. 5a), and on average it became even more strongly
negative in 2013 compared to 2012 (Fig. 5b). Please notethat the relationship between abundance and radiation forthe different species in 2011 was positively related to therelationship for different species in 2012, and the relationship between abundance and radiation for different
species in 2012 was positively related to the relationshipfor different species in 2013. Thus, species tended to become more negatively affected by radiation over time. In
contrast, there was no evidence that the relationshipbetween abundance and background radiation changed
with sample size in the species for which there were data
for at least 3 years (Kendall s = -0.060, SE = 0.098,
P = 0.542).
There was a significant difference in slope between
species with a herbivorous and a carnivorous diet (F =The number of individual birds of the 57 different species
recorded at Fukushima ranged from 1 to 1,715, mean
(SE) = 166.7 (48.6), median = 22 individuals.
There was a significant decline in the level of background radiation across years (Fig. 2; F = 1736.70,
df = 3, 1097, P \ 0.0001) with additional variation among
census points (F = 43.53, df = 399, 1097, P \ 0.0001).
The abundance of birds at Fukushima differed significantly among species, decreasing with increasing levels

Fig. 2 Box plots of background radiation (lSv/h) at census points
during the years 2011–2014. The box plots show median, quartiles,
5th and 95th percentiles and extreme observations

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Table 1 Abundance ofdifferent species of birds inrelation to radiation level inFukushima

Sum of squares

df

F

P

Estimate (SE)Radiation (R)

0.123

1

12.39

0.0004

Species (S)45.58344

103.750.00018.16\0.0001

R9S

3.587

44

Error

133.90213410-0.0063 (0.0018)

The overall model had the statistics F89,13410 = 55.47, r2 = 0.27, P \ 0.0001

Discussion

Fig. 3 a Number of bird species and b number of bird individuals at
census points in relation to background radiation (lSv/h). The lines
are the linear regression lines

25.20, df = 1, 55, r2 = 0.30, P \ 0.0001). Surprisingly
herbivorous species had a more strongly negative slope(-0.32 (SE = 0.04), N = 10) than carnivorous species(-0.10 (0.02), N = 47). There was also a significant
positive association between the slope of the relationshipbetween abundance and radiation and trophic level(F = 12.52, df = 2, 54, r2 = 0.29, P \ 0.0001). The
mean slope was the steepest for primary consumers [-0.32(SE = 0.04, N = 10) over low level predators (-0.10(0.02), N = 38) to top predators (-0.04 (0.13), N = 9)].

The main results of this study of radiation and species
richness and abundance of birds at Fukushima, Japan,
during 2011–2014 were that (1) overall abundance anddiversity of species on average decreased with increasinglevels of background radiation, (2) the relationship differedamong species, with most species decreasing, but somespecies increasing in abundance with increasing levels ofradiation, and (3) the relationship became more strongly
negative across years, while there was no effect of change
in abundance.
The overall negative relationship between abundance
and level of background radiation differed among species.
This result parallels previous findings from Chernobyl(Møller and Mousseau 2007a). We conducted our censuses
under the assumption that there would be no significant
difference in abundance because radiation should be distributed randomly across habitats that were censused.
Therefore, we should expect the effect of radiation to remain after controlling statistically for the confounding effects of habitat, weather and time of day. We suggest thatthe difference in the effect of radiation on abundance between Fukushima and Chernobyl could be ascribed todifferences in duration of exposure to radiation with (1)mutations accumulating for longer time in Chernobyl and(2) selection due to radiation not having acted for equallylong time in the two areas.
We had expected an effect of bioaccumulation of radionuclides in the food web because bioaccumulation iscommon (Voitovich and Afonin 2002; Yakushev et al.
1999) and animals at higher trophic levels generally havehigher levels of radionuclide concentrations than animals at
lower levels (e.g., Kryshev and Ryabov 1990; Kryshev
et al. 1992; Smith et al. 2002). However, the evidence
suggested an opposite effect, with more strongly negative
effects of radiation on abundance at low trophic levels. Ourfindings are therefore possibly more consistent with the
hypothesis that oxidative stress in contaminated areas andreduced antioxidant levels (Møller et al. 2005) are a consequence of chronic radiation exposure (Møller andMousseau 2007b), with negative effects on reproduction
and survival and ultimately population trends.

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Table 2 Slope of the relationship between abundance and level ofradiation after controlling statistically for potentially confounding
variables (see ‘‘Methods’’) based on observations from 1,500 census
points, level of significance of this relationship and the number ofindividuals that were censused for different species of birds
Species
Accipiter gentilis

Slope

P

No. individuals

Table 2 continued
Species

Slope

Phasianus colchicus-0.00410.55607

Phasianus soemmeringii-0.00560.0446

60.00470.00280.21580.15191
3

Picus awokera
Regulus regulusP

No. individuals

0.00040.8295

3-0.1579\0.0001

180

Streptopelia orientalis

0.1067\0.0001

155

Aegithalos caudatus

0.04700.2411

54

Sturnus cineraceus-0.00880.697955

Alauda arvensis

0.00200.44395

Tarsiger cyanurus-0.0001

0.95102

0.00360.11662
1

Acrocephalus arundinaceus

0.00080.49391

Terpsiphone atrocaudata

Anas poecilorhyncha-0.0018

0.60898

Troglodytes troglodytes

0.00080.4784

Apus affinis-0.0067

0.2466

6

Turdus cardis

0.00380.00328

Ardea cinerea-0.01290.031622

Urosphena squameiceps-0.00150.790626

0.00220.16752

Zosterops japonica

0.02220.0831

118

Butastur indicus
Buteo buteo

0.0054-0.08120.2859\0.0001

14
99

Carduelis sinica-0.06810.2086

238

Cettia diphone-0.1798\0.0001

1715

Cinclus pallasii

0.00300.43385

Alcedo atthis

Bambusicola thoracica

Cisticola juncidis

0.00230.1475

2

Corvus corone-0.3069\0.0001

559

Corvus macrorhynchos

0.03620.2644446

Cuculus canorus

0.00490.174310-0.0534

0.0027284

Cuculus saturatus

0.00190.1014

1

Cyanopica cyanus-0.00150.7763130.00350.12784-0.0056

0.465620

Cuculus poliocephalus

Cyanoptila cyanomelana
Delichon urbica
Dendrocopos kizuki

0.01370.119256

Emberiza cioides
Eophona personata-0.1896-0.0015\0.0001
0.2039703
1

Falco peregrinus-0.00090.44161

Falco tinnunculus-0.00020.8821

1

Ficedula narcissina

0.0344\0.000153

Garrulax canorus-0.02480.040294

Garrulus glandarius

0.01390.007736

Hirundo rustica-0.2201\0.0001

419

Hypsipetes amaurotis-0.0494

0.20691618

Lanius bucephalus-0.0156

0.1086

71

Milvus migrans-0.00110.910456

Motacilla alba

-0.01610.004419

Motacilla cinerea-0.0640\0.0001

66

Motacilla grandis

44-0.0487\0.0001

Parus ater

0.0345\0.000145

Parus major

0.03150.0315137

Parus montanus
Parus varius

0.00370.00720.58790.213323
22

Passer montanus-0.5249\0.0001

1114

Pericrocotus divaricatus-0.0004

0.91801Phalacrocorax carbo

0.00120.5993

4

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Fig. 4 Box plots of the correlation coefficients between abundanceand background radiation during the years 2011–2014. The box plotsshow median, quartiles, 5th and 95th percentiles and extreme
observations

This study has implications for the assessment of biological effects of ionizing radiation on free-living organisms. We have shown that the negative impact of radiation
on abundance and species richness changes over time, andthis effect varies among species. If we had not conducted
the first breeding bird census in 2011 immediately after the
Fukushima accident, we would not have been able todocument a temporal change in abundance as we havereported here. Although bird species on average declined inabundance with increasing background radiation, there
were several species that clearly increased in abundance.
The reason for such changes can be changes in land use or
release from competition due to reductions in the abundance of other species. The patterns of change inAuthor's personal copy
J Ornithol

Fig. 5 Relationship between correlation coefficients for abundanceof different bird species and background radiation (lSv/h) at census
points during (a) 2011 and 2012 and (b) 2012 and 2013

abundance with radiation level were only weakly speciesspecific, and even closely related species such as barnswallow Hirundo rustica and house martin Delichon urbica, carrion crow Corvus corone and jungle crow Corvus
macrorhynchos, and great tit Parus major and varied tit
Parus varius varied significantly in the impact of radiation
on abundance (Table 2). This makes it unlikely that competitive release is an important factor.
Although there has been great public interest concerning
the ecological, genetic and potential health consequencesof the Fukushima radiological disaster, basic research todate has been surprisingly limited with only a handful ofstudies published since the disaster. A recent study of bull
sperm and testis from the Fukushima region found noevidence for significant histological changes in the testes orsperm morphology (Yamashiro et al. 2013), although thisstudy was very preliminary with only two bulls from a

relatively uncontaminated part of Fukushima represented
for the analysis of sperm. A study of aphids revealed large
effects of radiation on morphology, although aberrant
forms were only reported for one location in an area ofrelatively low contamination (Akimoto 2014). Similarly, a
recent study of Japanese macaques found evidence for radiation effects on various characteristics of their blood, but
individuals used in this study were obtained from areas
surrounding Fukushima City where contamination levels,
though measurable, are low relative to other parts ofFukushima Prefecture (Ochiai et al 2014). Ishida (2013)
reported on surveys of some bird populations living in
more heavily contaminated areas of the region and suggested that there was no evidence of significant declines
resulting from the disaster. However, the number of sites
surveyed was relatively few (56 in May and 38 in June2012), and the analyses did not control for the many otherpotentially confounding factors that influence bird abundance and distribution, making this study very preliminary.
Recent seminal studies of butterflies exposed to radioactive
contaminants associated with the Fukushima disaster foundstrong evidence for increased mutation rates, developmental abnormalities and population effects as a directconsequence of exposure to radionuclides (Hiyama et al.
2012, 2013). These studies by Hiyama et al. (2012, 2013)
were greatly strengthened by laboratory experiments thatused both internal and external radiation sources, and theseunambiguously supported observations of the elevatedmutation rates and phenotypic effects observed in the field(Møller and Mousseau 2013), although, as with otherstudies, the number of populations studied, and hence thelevel of replication of observations, was very limited.
Murase et al. (2015) made an equally compelling case forradiation having a negative impact on reproductive performance in the decline of Japanese goshawks Accipitergentilis fujijamae compared to the pre-accident years, theprogressive decline over time being directly linked to the
air dose rate.
In conclusion, we have shown substantial evidence
based on rigorous and highly replicated observations acrossspace and time that is consistent with the hypothesis thatthe species richness and abundance of different species ofbirds were suppressed at high levels of background radiation in Fukushima. The relationship between abundance
and radiation differed significantly among species, withmost species decreasing, but some species increasing inabundance with increasing levels of radiation. Importantly,
the relationship between abundance and radiation became
more strongly negative over the 4 years studied, while
there was no change in the effect of radiation on abundancewith change in abundance over years.
Acknowledgments We gratefully acknowledge the logistic support and help in Japan by Prof. A. Hagiwara, Prof.

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K. Ueda, Prof. K. Kawatsu, S. Matsui, S. Kasahara, T.
Kanagawa, K. Kawai, H. Suzuki and K. Koyama. We areespecially grateful to the people of Fukushima Prefecture
who permitted us to conduct this study. We thank Dr.
S. Welch for help in preparing the contamination map of
Fukushima Prefecture. We gratefully acknowledge support
from the US National Science Foundation, the Universityof South Carolina School of the Environment, the NATO
CLG program, the CRDF, the Fulbright Program, the National Geographic Society and the Samuel Freeman
Charitable Trust for Research in Chernobyl, and the
University of South Carolina, the Samuel Freeman
Charitable Trust, Qiagen GmbH, the Chubu University
Science and Technology Center and anonymous gifts fromindividual citizens for research in Japan.

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