The pale grass blue butterfly in ex-evacuation zones 5.5 years after the Fukushima nuclear accident: Contributions of initial high-dose exposure to transgenerational effects

Biological impacts of the Fukushima nuclear accident have been reported in various organisms but have not been evaluated sufficiently. Here, we collected the pale grass blue butterfly, Zizeeria maha, in September 2016, 5.5 years after the accident, from ex-evacuation zones in Fukushima Prefecture to evaluate the remaining biological effects of the accident. Although the morphological abnormality rate was not high, it was significantly positively correlated with the initial ¹³¹I and ¹³⁷Cs deposition levels (as of March 2011). The capture rate was negatively correlated with the initial ¹³⁷Cs deposition level at the borderline of significance. Neither the abnormality rate nor the capture rate was correlated with the ground radiation dose (as of September 2016). Generalized linear model (GLM) analysis also indicated contributions of the initial ¹³¹I and ¹³⁷Cs deposition levels but not the ground radiation dose. These results suggest that the butterflies present in the ex-evacuation zones in 2016 were still affected, although not severely, mainly because of the initial high-dose exposure to radioiodine, radiocesium, and other radionuclides. We conclude that transgenerational effects of radioactive contamination have successively manifested in the 5.5 years since the accident, possibly through genetic mutations, although potential contributions of other modes of damage cannot be ignored.     

Measurements of gamma (γ)-emitting radionuclides with a high-purity germanium detector: the methods and reliability of our environmental assessments on the Fukushima 1 Nuclear Power Plant accident

The severe accident of Fukushima 1 Nuclear Power Plant due to the Tohoku Region Pacific Coast Earthquake in 11 March 2011 caused wide contamination and pollution by radionuclides in Fukushima and surrounding prefectures. In the current JPR symposium, a group of plant scientists attempted to examine the impact of the radioactive contamination on wild and cultivated plants. Measurements of gamma (γ) radiation from radionuclides in “Fukushima samples”, which we called and collected from natural and agricultural areas in Fukushima prefecture were mostly done with a high-purity Ge detector in the Graduate School of Maritime Sciences, Kobe University. In this technical note, we describe the methods of sample preparation and measurements of radioactivity of the samples and discuss the reliability of our data in regards to the International Atomic Energy Agency (IAEA) Interlaboratory comparisons and proficiency test (IAEA proficiency test).     

Radionuclide analysis on bamboos following the Fukushima nuclear accident

In response to contamination from the recent Fukushima nuclear accident, we conducted radionuclide analysis on bamboos sampled from six sites within a 25 to 980 km radius of the Fukushima Daiichi nuclear power plant. Maximum activity concentrations of radiocesium (134)Cs and (137)Cs in samples from Fukushima city, 65 km away from the Fukushima Daiichi plant, were in excess of 71 and 79 kBq/kg, dry weight (DW), respectively. In Kashiwa city, 195 km away from the Fukushima Daiichi, the sample concentrations were in excess of 3.4 and 4.3 kBq/kg DW, respectively. In Toyohashi city, 440 km away from the Fukushima Daiichi, the concentrations were below the measurable limits of up to 4.5 Bq/kg DW. In the radiocesium contaminated samples, the radiocesium activity was higher in mature and fallen leaves than in young leaves, branches and culms.     

The diet of Atlantic Yellow-legged Gulls (<Emphasis Type="Italic">Larus michahellis atlantis</Emphasis>) at an oceanic seabird colony: estimating predatory impact upon breeding petrels

The diet and breeding ecology of Yellow-legged Gulls (Larus michahellis atlantis) were studied on Selvagem Grande, North Atlantic in the nesting season of 2007. We collected and analyzed 715 pellets from adults. The most frequent prey were White-faced Storm-petrels (Pelagodroma marina; present on 40.8% of all pellets) and the endemic land snails (Theba macandrewiana; present on 36.5% of all pellets). Other birds, namely Cory’s Shearwaters (Calonectris diomedea), Macaronesian Shearwaters (Puffinus assimilis), Bulwer’s Petrels (Bulweria bulwerii), and Band-rumped Storm-petrels (Oceanodroma castro) were relatively less frequent, but overall, seabirds were present in ca. 50% of all pellets, representing an estimated 60.4% of all mass consumed by gulls. We estimate that the contribution of seabirds to the overall caloric balance accounted for 82.5% of all energy consumed. The number of gull pairs breeding on Selvagem Grande was 12 on 2005 and 2007. Breeding success was low (0.92 and 0.25 juveniles per breeding pair, respectively). Using a simple bioenergetics model, we estimate the breeding gull population to have the potential to consume approximately 4,847 adult/sub-adult seabirds in 3.5 months in order to meet its energetic requirements. The importance of the estimated predation levels is discussed and some management actions are suggested.     

THE BREEDING SEABIRDS OF TROMELIN ISLAND (WESTERN INDIAN OCEAN): POPULATION SIZES,TRENDS AND BREEDING PHENOLOGY

Le Corre, M. 1996. The breeding seabirds of Tromelin Island (western Indian Ocean): population sizes, trends and breeding phenology. Ostrich 67: 155–159.

Formerly six or eight species of seabirds bred on Tromelin Island, but currently only two species do so: The Redfooted Booby Sula sula and the Masked Booby S. dactylatra. The last two species which became locally extinct, the Lesser Frigatebird Fregata ariel and the Greater Frigatebird F. minor, probably stopped breeding on the island as a consequence of human disturbance to breeding colonies. The populations of the two species of booby have opposing trends since 1954. The Masked Booby's population increased from 60 pairs in 1954 to 200–250 pairs in 1996 while the Red-footed Booby's population decreased from 500 pairs in 1968 to 130–180 pairs in 1996. The impacts of human settlement, introduced brown rats Rattus norvegicus, local extinction of the Greater Frigatebird and other factors are discussed to explain these changes in population sizes. New data are provided on the breeding phenology of the two species of booby. Finally, the importance of this island for the conservation of seabirds in the western Indian Ocean is discussed.     

Impact of the Fukushima nuclear accident on obesity of children in Japan (2008–2014)

This study used prefecture-level panel data from Japan for the period 2008–2014 to investigate the influence of the 2011 Fukushima nuclear accident on the body mass index (BMI) z-score and obesity rates of children over time. I adopted a difference-in-differences approach and found the following: (1) for the cohort aged 5–7 years in 2010, the BMI z-score and obesity rates in disaster-affected areas were higher than in other areas, although this was not observed for the other cohorts; (2) for the cohort aged 5–7 years in 2010, the influence of the accident persisted even after 3 years; and (3) the differences in the BMI z-score and obesity rate before and after the accident were greater for Fukushima Prefecture than for the other affected areas (Iwate and Miyagi prefectures). I infer that health-conscious parents, whose children had lower BMIs, may have moved from Fukushima, thereby increasing the BMI z-score of the child population living in Fukushima by around 0.05 for the cohort aged 5–7 years. The enforced reduction in physical activity increased the BMI z-score of children living in Fukushima by around 0.19 for that cohort.     

Contrasting effects of tropical cyclones on the annual survival of a pelagic seabird in the Indian Ocean

Tropical cyclones are renowned for their destructive nature and are an important feature of marine and coastal tropical ecosystems. Over the last 40 years, their intensity, frequency and tracks have changed, partly in response to ocean warming, and future predictions indicate that these trends are likely to continue with potential consequences for human populations and coastal ecosystems. However, our understanding of how tropical cyclones currently affect marine biodiversity, and pelagic species in particular, is limited. For seabirds, the impacts of cyclones are known to be detrimental at breeding colonies, but impacts on the annual survival of pelagic adults and juveniles remain largely unexplored and no study has simultaneously explored the direct impacts of cyclones on different life‐history stages across the annual life cycle. We used a 20‐year data set on tropical cyclones in the Indian Ocean, tracking data from 122 Round Island petrels and long‐term capture–mark–recapture data to explore the impacts of tropical cyclones on the survival of adult and juvenile (first year) petrels during both the breeding and migration periods. The tracking data showed that juvenile and adult Round Island petrels utilize the three cyclone regions of the Indian Ocean and were potentially exposed to cyclones for a substantial part of their annual cycle. However, only juvenile petrel survival was affected by cyclone activity; negatively by a strong cyclone in the vicinity of the breeding colony and positively by increasing cyclone activity in the Northern Indian Ocean where they spend the majority of their first year at sea. These contrasting effects raise the intriguing prospect that the projected changes in cyclones under current climate change scenarios may have positive as well as the more commonly perceived negative impacts on marine biodiversity.     

Intra-population variation in the diet of an avian top predator: generalist and specialist foraging in Great Black-backed Gulls Larus marinus

ABSTRACT

Capsule: Great Black-backed Gulls Larus marinus breeding on Skokholm, UK, fed predominantly on seabirds, rabbits, refuse, and marine prey, with the majority of pairs being dietary generalists, but with some specialist pairs.

Aims: To understand the significance of Great Black-backed Gulls as top predators on a small offshore island with internationally important numbers of breeding seabirds (Skokholm, UK) by quantifying their diet and to determine how this varies within the breeding season, to test for pair-level dietary specialization and to examine the consequences of dietary differences for reproductive performance.

Methods: Regurgitated pellets were collected and analysed from 26 breeding pairs on Skokholm during 2017 and related to breeding success.

Results: Analysis of 1035 pellets revealed that, overall, Great Black-backed Gulls fed on seabirds (48% – mostly Manx Shearwaters Puffinus puffinus), mammals (38% – mostly European Rabbits Oryctolagus cuniculus), anthropogenic waste (7%), and marine prey (7%). Diet varied among pairs with 18 (73%) generalist pairs and 7 (27%) specialist pairs (of which, 5 were bird specialists and 2 were mammal specialists). Diet also varied seasonally, but pair-level dietary diversity was repeatable through the breeding season. Dietary diversity did not covary with breeding success.

Conclusion: Great Black-backed Gulls are top predators on Skokholm. Variation in diet among pairs emphasizes that not all individuals contribute equally in terms of predation. Understanding the incidence of this variation has important ecological implications, particularly where apex predators may exert a strong top-down influence.     

Radioactive pollution and accumulation of radionuclides in wild plants in Fukushima

The radionuclide status of wild plants and soil in the Fukushima area was investigated during the period May 2011 to October 2012, using an imaging plate (autoradiograms) or a high purity germanium detector. Analyses of autoradiograms showed that wild plants grown in March 2011 were strongly polluted with fallout released from the Fukushima 1 Nuclear Power Plant. The radioactivity was mostly due to fallout adsorbed on the surface of the plants. On the other hand, a number of herbaceous plants were regularly collected in the Fukushima area and their radionuclide concentrations were measured with a high-purity germanium detector. Plants grown in March 2011 showed very high levels of ¹³⁴Cs and ¹³⁷Cs, but these radioactivity levels decreased rapidly after July 2011 and eventually became lower than that of endogenous ⁴⁰K. During this period, the radioactivity of the soil remained high. We therefore suppose that a significant proportion of the radioactivity detected from plants harvested after July 2011 was most likely derived from soil dust attached on the plant surface. Autoradiograms of rice plants were virtually identical between plants cultivated in Fukushima and Osaka area, reflecting the background radiation due to ⁴⁰K.     

Status,trends, and patterns of covariation of breeding seabirds at St Lazaria Island,Southeast Alaska, 1994–2006

Aim We examined patterns of covariation among piscivorous and planktivorous seabirds breeding at St Lazaria Island in order to evaluate their responses to interannual changes in sea surface temperature, a variable that affects marine food webs. In addition, we evaluated seabird population trends for responses to decadal‐scale changes in the marine ecosystem. Location St Lazaria Island, Sitka Sound, Alaska. Methods Established seabird monitoring protocols for the Alaska Maritime National Wildlife Refuge were followed in estimating population trends, the timing of nesting events and the reproductive success of eight species of seabirds between 1994 and 2006. Results  Population increases were noted for storm‐petrels (Oceanodroma furcata and O. leucorhoa), rhinoceros auklets (Cerorhinca monocerata) and glaucous‐winged gulls (Larus glaucescens). We found no population trend for pelagic cormorants (Phalacrocorax pelagicus), but it appeared that populations of common (Uria aalge) and thick‐billed (U. lomvia) murres and of tufted puffins (Fratercula cirrhata) declined. We detected no linear trends in either breeding chronology or reproductive success over the study period for any seabird. All species of piscivorous seabirds apparently responded similarly to environmental cues as there was a positive covariation among species in the timing of nesting. Piscivores tended to nest earlier, and most species had higher rates of reproductive success in years with relatively warm spring sea temperatures. In contrast, planktivorous Leach’s storm‐petrels (O. leucorhoa) tended to nest earlier when spring and summer sea temperatures were relatively cool. Clearly, seabirds at St Lazaria were responding to interannual changes in sea temperatures near the breeding colony, probably as a result of effects on the food webs. Main conclusions Every seabird species we monitored at St Lazaria exhibited significant population trends between 1994 and 2006. For most species there appeared to be a relationship between both the timing of nesting and reproductive rates and spring or summer sea surface temperatures. Responses at both decadal (populations) and interannual (timing and reproductive success) scales make seabirds useful candidates for helping to monitor change in the marine environment.     

Individual radiation exposure dose due to support activities at safe shelters in Fukushima Prefecture

Immediately after the accidents in the nuclear power stations in Fukushima on March 11, the Japanese Government ordered the evacuation of the residents within a 20-km radius from the station on March 12, and asked various institutions to monitor the contamination levels of the residents. Hirosaki University, which is located 355 km north of Fukushima City, decided to send support staff to Fukushima. This report summarizes the results of the exposure of 13 individual teams from March 15 to June 20. The support teams surveyed more than 5,000 people during this period. Almost all subjects had external contamination levels of less than 13 kcpm on Geiger-Müller (GM) survey meter, which is categorized as "no contamination level." The 1(st) team showed the highest external exposure dose, but the 4(th) team onward showed no significant change. Subsequently, the internal radiation exposure was measured using a whole body counter that indicated undetectable levels in all staff members. Although the measured external radiation exposure dose cannot have serious biological effects on the health of an individual, a follow-up study of the residents in Fukushima and other regions where the radioactive material has spread will be required for a long time.     

Current Measures on Radioactive Contamination in Japan: A Policy Situation Analysis

Background

The Great East Japan Earthquake on 11^th March 2011 and the subsequent Fukushima Dai-ichi nuclear power plant disaster caused radioactive contamination in the surrounding environment. In the immediate aftermath of the accident the Government of Japan placed strict measures on radio-contamination of food, and enhanced radio-contamination monitoring activities. Japan is a pilot country in the WHO Foodborne Disease Burden Epidemiology Reference Group (FERG), and through this initiative has an opportunity to report on policy affecting chemicals and toxins in the food distribution network. Nuclear accidents are extremely rare, and a policy situation analysis of the Japanese government’s response to the Fukushima Dai-ichi nuclear accident is a responsibility of Japanese scientists. This study aims to assess Japan government policies to reduce radio-contamination risk and to identify strategies to strengthen food policies to ensure the best possible response to possible future radiation accidents.

Methods and Findings

We conducted a hand search of all publicly available policy documents issued by the Cabinet Office, the Food Safety Commission, the Ministry of Health, Labor and Welfare (MHLW), the Ministry of Agriculture, Forestry and Fishery (MAFF) and prefectural governments concerning food safety standards and changes to radiation and contamination standards since March 11^th, 2011. We extracted information on food shipment and sales restrictions, allowable radio-contamination limits, monitoring activities and monitoring results. The standard for allowable radioactive cesium (Cs-134 and Cs-137) of 100 Bq/Kg in general food, 50 Bq/Kg in infant formula and all milk products, and 10 Bq/Kg in drinking water was enforced from April 2012 under the Food Sanitation Law, although a provisional standard on radio-contamination had been applied since the nuclear accident. Restrictions on the commercial sale and distribution of specific meat, vegetable and fish products were released for areas at risk of radioactive contamination. Monitoring of radioactive materials in food products in the prefectures has been mainly conducted before shipment to restrict the distribution of radio-contaminated foods. Between March 2011 and March 2012, 133,832 tests of non-commercial and commercial products were conducted, and 1,204 tests (0.9%) were found to violate the provisional standards. Since April 2012, 278,275 tests were conducted, and 2,372 tests (0.9%) were found to violate the revised standards. MHLW assessment of representative market baskets of foodstuffs at 15 locations throughout Japan between February and March 2014 found very low estimated dietary intake of radioactive cesium (0.0007–0.019 mSv/year), as did assessments of the contents of an average day’s food. Monitoring of fisheries products in coastal areas affected by the nuclear accident found very limited and declining radio-contamination of live fish outside of Fukushima prefecture. Fisheries monitoring is of limited geographical scope and covers only certain fishes.

Conclusions

Area-specific bans on production and distribution have been effective in preventing radioactive contamination in the Japanese food market. Currently there is no major concern about radioactive cesium concentrations in retail foodstuffs in Japan, and very low levels of contamination at the production and wholesale stage. However, because the residue limits and food safety policies were revised on an ad hoc, emergency basis after the nuclear accident, the monitoring procedure needs to be reviewed based on objective and scientifically rational criteria. A transparent and objective scientific framework is needed for prioritizing foodstuffs for inspection and revising Prefecture-specific restrictions. Monitoring of fishes and other seafood products in the wild should be regularized and the information made more publicly accessible, and monitoring activities expanded to identify foodstuffs that are no longer a food safety risk. Consultation with producers and consumers should be more formalized to ensure their concerns are incorporated into regular policy reviews in an appropriate and transparent manner. However, despite the limited available knowledge on best practice in food control and enforcement of provisional radio-contamination limits after the accident, current Japanese policy is sufficient to protect the Japanese public from major risk of radio-contamination from the commercial food market.     

Evaluation of Environmental Contamination and Estimated Radiation Doses for the Return to Residents’ Homes in Kawauchi Village,Fukushima Prefecture

To evaluate the environmental contamination and radiation exposure dose rates due to artificial radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), the concentrations of artificial radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming artificial radionuclides from all samples were ¹³⁴Cs and ¹³⁷Cs. The estimated external effective doses from soil samples were 0.42–7.2 µSv/h (3.7–63.0 mSv/y) within the 20-km radius from FNPP and 0.0011–0.38 µSv/h (0.010–3.3 mSv/y) within the 20–30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents’ homes after the FNPP accident.     

Internal Radiation Exposure Dose in Iwaki City,Fukushima Prefecture after the Accident at Fukushima Dai-ichi Nuclear Power Plant

As a result of the accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) on 11 March 2011, a huge amount of radionuclides, including radiocesium, was released and spread over a wide area of eastern Japan. Although three years have passed since the accident, residents around the FNPP are anxious about internal radiation exposure due to radiocesium. In this study, we screened internal radiation exposure doses in Iwaki city of Fukushima prefecture, using a whole-body counter. The first screening was conducted from October 2012 to February 2013, and the second screening was conducted from May to November 2013. Study participants were employees of ALPINE and their families who underwent examination. A total of 2,839 participants (1,366 men and 1,473 women, 1–86 years old) underwent the first screening, and 2,092 (1,022 men and 1,070 women, 1–86 years old) underwent the second screening. The results showed that 99% of subjects registered below 300 Bq per body in the first screening, and all subjects registered below 300 Bq per body in the second screening. The committed effective dose ranged from 0.01–0.06 mSv in the first screening and 0.01–0.02 mSv in the second screening. Long-term follow-up studies are needed to avoid unnecessary chronic internal exposure and to reduce anxiety among the residents by communicating radiation health risks.     

Genotoxicity and toxicity assay of water sampled from the underground nuclear explosion site in the north of the Perm region (Russia)

The results of our study revealed a local biologically relevant surface water contamination in the radionuclide anomaly in the north of Russia (Perm region) by means of Allium shoenoprasum L. the anaphase-telophase chromosome aberration assay. This radionuclide anomaly was formed in 1971 as a result of an underground nuclear explosion with soil excavation. Specific activities of main dose-forming radionuclides in all examined reservoirs are below intervention levels officially adopted in Russia for drinking water. We found that 90Sr significantly contribute to induction of cytogenetic disturbances. Our previous and described here data suggest that metal ions and radionuclides combined exposure on the various biota species (with the dose below permissible exposure limits for human) may cause substantial biological effects in part be due to synergic response. The findings described here indicated that development of a new concept of radiation protection for humans and biota should be based on the clear understanding of biological effects of low doses of radiation in chronic exposure to multi-pollutant mixtures.     

2013年北太平洋公海渔场柔鱼体内典型放射性核素分析及风险评估

为了解福岛核泄漏放射性核素对北太平洋公海渔场的后续性污染影响情况,于2013年8—11月在北太平洋公海渔场(40°—44° N、145°—160° E)采集柔鱼样品,利用超低本底HPGe γ 谱仪分析5种放射性核素.结果表明: ¹³⁴Cs和^110mAg未检测出高于本底值的比活度,而²¹⁰Pb、¹³⁷Cs和⁴⁰K均有检出.其中²¹⁰Pb在柔鱼体的比活度范围为0.99～7.60 Bq·kg^-1,¹³⁷Cs的比活度范围为最低检测限～0.37 Bq·kg^-1,⁴⁰K的比活度范围为46.00～107.00 Bq·kg^-1.²¹⁰Pb核素含量在柔鱼250～300 mm胴长组分布最高;在200～250和>400 mm胴长组中最低.¹³⁷Cs含量在柔鱼200～250 mm胴长组中最高;在250～300和350～400 mm胴长组较低.⁴⁰K核素含量在柔鱼250～300 mm胴长组中最高,在150～200 mm胴长组最低,总体分布比较均匀.3种核素在柔鱼的不同组织中含量不同,但均在内脏中含量最高.通过风险评估发现,北太平洋公海渔场所有检测的海洋生物的放射性核素含量值与基准值的熵值均未超过1,说明目前核辐射对该海域渔业资源的影响暂无大风险.研究可为福岛核事故对海洋环境生态影响及公众健康危害评估提供理论依据.     

Increased oxidative stress in barn swallows from the Chernobyl region

The Chernobyl nuclear accident produced the largest unintended release of radionuclides in history, with dramatic consequences for humans and other organisms. Exposure to ionizing radiation is known to reduce circulating and stored levels of specific antioxidants in birds and humans, thus potentially increasing oxidative stress. However, overall effects of radioactive exposure on oxidative status have never been investigated in any free ranging vertebrate. We measured plasma antioxidant capacity and concentration of reactive oxygen metabolites in adult barn swallows (Hirundo rustica) from colonies with variable background radiation levels in the Chernobyl region in Ukraine and Belarus. We predicted that antioxidants would decrease while reactive oxygen metabolites would increase with exposure to increasing levels of radiation at the breeding sites. Consistent with this expectation, radiation level positively predicted plasma concentration of reactive oxygen metabolites, whereas no significant covariation was found with non-enzymatic plasma antioxidant capacity. An index of oxidative stress was also larger in barn swallows exposed to high contamination levels. Thus, radioactive contamination appeared to be responsible for the increased generation of reactive oxygen metabolites and the imbalance between reactive oxygen metabolites and non-enzymatic plasma antioxidant capacity.     

Radiation Dose Reduction Efficiency of Buildings after the Accident at the Fukushima Daiichi Nuclear Power Station

Numerous radionuclides were released from the Fukushima Daiichi Nuclear Power Station (F1-NPS) in Japan following the magnitude 9.0 earthquake and tsunami on March 11, 2011. Local residents have been eager to calculate their individual radiation exposure. Thus, absorbed dose rates in the indoor and outdoor air at evacuation sites in the Fukushima Prefecture were measured using a gamma-ray measuring devices, and individual radiation exposure was calculated by assessing the radiation dose reduction efficiency (defined as the ratio of absorbed dose rate in the indoor air to the absorbed dose rate in the outdoor air) of wood, aluminum, and reinforced concrete buildings. Between March 2011 and July 2011, dose reduction efficiencies of wood, aluminum, and reinforced concrete buildings were 0.55±0.04, 0.15±0.02, and 0.19±0.04, respectively. The reduction efficiency of wood structures was 1.4 times higher than that reported by the International Atomic Energy Agency. The efficiency of reinforced concrete was similar to previously reported values, whereas that of aluminum structures has not been previously reported. Dose reduction efficiency increased in proportion to the distance from F1-NPS at 8 of the 18 evacuation sites. Time variations did not reflect dose reduction efficiencies at evacuation sites although absorbed dose rates in the outdoor air decreased. These data suggest that dose reduction efficiency depends on structure types, levels of contamination, and evacuee behaviors at evacuation sites.     

Removal Efficiency of Radioactive Cesium and Iodine Ions by a Flow-Type Apparatus Designed for Electrochemically Reduced Water Production

The Fukushima Daiichi Nuclear Power Plant accident on March 11, 2011 attracted people’s attention, with anxiety over possible radiation hazards. Immediate and long-term concerns are around protection from external and internal exposure by the liberated radionuclides. In particular, residents living in the affected regions are most concerned about ingesting contaminated foodstuffs, including drinking water. Efficient removal of radionuclides from rainwater and drinking water has been reported using several pot-type filtration devices. A currently used flow-type test apparatus is expected to simultaneously provide radionuclide elimination prior to ingestion and protection from internal exposure by accidental ingestion of radionuclides through the use of a micro-carbon carboxymethyl cartridge unit and an electrochemically reduced water production unit, respectively. However, the removability of radionuclides from contaminated tap water has not been tested to date. Thus, the current research was undertaken to assess the capability of the apparatus to remove radionuclides from artificially contaminated tap water. The results presented here demonstrate that the apparatus can reduce radioactivity levels to below the detection limit in applied tap water containing either 300 Bq/kg of ¹³⁷Cs or 150 Bq/kg of ¹²⁵I. The apparatus had a removal efficiency of over 90% for all concentration ranges of radio–cesium and –iodine tested. The results showing efficient radionuclide removability, together with previous studies on molecular hydrogen and platinum nanoparticles as reactive oxygen species scavengers, strongly suggest that the test apparatus has the potential to offer maximum safety against radionuclide-contaminated foodstuffs, including drinking water.     

Intra- and interannual variation in the diet of the Magellanic penguin (Spheniscus magellanicus) at Martillo Island,Beagle Channel

Knowledge of seabirds’ diet at each breeding site and its temporal variation is key to understanding and evaluating how changes in marine resources affect each seabird population. In this study, we determined the diet of Magellanic penguins (MP, Spheniscus magellanicus) at Martillo Island, accounting for sex, breeding stage and year. We analyzed a total of 144 stomach contents during three consecutive breeding seasons (2006–2007, 2007–2008 and 2008–2009) and stages (incubation, early and late chick-rearing). MP fed mainly on fuegian sprat (Sprattus fuegensis), which represented 75 % of the biomass consumed by birds during the entire study. The next important prey was squat lobster (Munida gregaria), followed by Patagonian squid (Loligo gahi). Both sexes consumed similar prey items. We observed variation in diet relative composition among breeding years and stages. Fuegian sprat consumption decreased throughout the years whereas squat lobster increased. Penguins consumed a higher proportion of squat lobster and Patagonian squid during the incubation stage than in the chick-rearing stages, whereas fuegian sprat was almost the only prey item consumed during the late chick-rearing stage. MPs show certain flexibility in the use of resources probably as a response to changes in prey populations. Variability in the diet among different reproductive stages could be related to changes in the distribution and abundance of their main prey near the colony during the breeding season together with changes in the energy requirements of seabirds.