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The March 2011 Fukushima Dai-ichi Nuclear Power Plant accident in Japan released 520 PBq of radionuclides compared to a total release of 5300 PBq from the Chornobyl Nuclear Power Plant accident. Both nuclear accidents resulted in deposition of radiocesium throughout the northern hemisphere, and a plethora of studies have been performed regarding radiocesium (137Cs) behavior. However, few studies have assessed the impact of precipitation on 137Cs deposition in forests. Wide-scale environmental measurements from 2011 and 2016 were used to determine the differences in 137Cs deposition because of precipitation following the Fukushima accident. In areas where wet deposition processes were dominant, dense forests generally had lower ambient dose rates and levels of contamination on forest floors than other stands with fewer stems per hectare in 2011. Similar tendencies were not observed in areas that were primarily subject to dry deposition nor were any trends observed in 2016. 137Cs was retained in dense forest canopies for an extended period regardless of the deposition mode. Additionally, it was found that the initial retention of radionuclides by forest canopies is in general higher for areas with predominantly dry deposition. Incorporation of radiocesium into wood tissues was the same for both wet and dry deposition.

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released the most significant quantity of radiocesium into the environment since Chernobyl, and detailed measurements over the initial 5 years provide new insights into fluvial redistribution of radiocesium. We found that the high initial activity concentration of 137Cs-bearing suspended sediment in rivers was followed by a steep exponential decline (λ1) which extended to approximately 1 year after the accident, while the rate of initial decline in radiocesium activity concentration in water was an order of magnitude higher than rates measured after Chernobyl. Fluvial transport of 137Cs to the ocean from the Abukuma river totaled 12 TBq between June 2011 and August 2015 and almost all this radiocesium (96.5%) was transported in the particulate form. The primary sources of 137Cs were paddy fields, farmland, and urban areas [plaque-forming unit (PFU)], discharging 85% of the exported 137Cs from 38% of the watershed area. After 1 year, activity concentrations were lower and exhibited a more gradual secondary decline (λ2) which was associated with reduced radiocesium losses from PFU areas, while forest areas continue to represent more stable contaminant stores.

ABSTRACTThis study determined the initial distribution of Fukushima reactor-derived radiocesium fallout in forest areas of Fukushima Prefecture based on analysis of airborne monitoring surveys by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT). The results of the fifth airborne monitoring surveys were compared with the third airborne survey data in order to correct for variation of deposition density due to multiple factors such as weathering processes and measurement uncertainties between two surveys. Finally, the results of the third and the corrected fifth airborne surveys were combined to reconstruct the initial radiocesium fallout map over the whole Fukushima Prefecture area following the Fukushima reactor accident. Our calculation results showed that forest areas accumulated 72% of the total atmospheric input of 137Cs to the land of Fukushima Prefecture. The deposition density in forest areas showed significant variability among municipalities. Nevertheless, forest areas accumulated a large percentage of atmospherically deposited radiocesium in many municipalities. Statistical analysis of the variability in 137Cs deposition density indicated that deposition density varied significantly, even within a municipality. Furthermore, the inconsistency in the probability distributions of measured deposition density among municipalities makes it difficult to obtain a representative initial radiocesium fallout input following the accident. To reduce uncertainty in environmental parameters related to radiocesium transfer in forest environments, we strongly recommend that the deposition density of initial 137Cs fallout at each location is determined by in-situ sampling survey and using the reconstructed 137Cs fallout map presented in this study.

Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa) plantations account for approximately 30% of the total forested area in Japan. Both are arbuscular mycorrhizal trees that leach more NO3−in response to nitrogen (N) deposition than do forests of ectomycorrhizal trees. However, little information is available about the size of N exports from these plantations. The aim of this study was to evaluate nonpoint source N exports from a N‐saturated plantation. We collected stream water samples in base‐flow (25 samples) and storm‐flow conditions (20 events) in a watershed (2.98 ha) where Japanese cypress and Japanese cedar were planted in 1969 (41 yr old). The annual NO3−export was calculated from load–discharge relationships. Atmospheric N deposition was also determined. The stream water contained high NO3−concentrations (160 and 165 μmol L−1during base flow and storm flow, respectively), indicating N saturation in the watershed. High bulk atmospheric N deposition (16.5 kg N ha−1yr−1) could explain the N saturation. There were only small variations in NO3−concentrations in stream water in response to discharge volume, because of the N saturation of the forest ecosystem. Consequently, there were only small errors in estimating annual NO3−exports from the studied watershed. The annual NO3−export was high (36.1 kg N ha−1yr−1), comparable to values reported for agricultural and urbanized areas. These results suggest that N‐saturated forest plantations can become important nonpoint N sources. Our results also suggest that N exports from forest plantations across Japan should be quantified to evaluate nonpoint source N accurately.

AbstractInterception loss (Ei) in forests has been studied widely. However, Eiparameters and modeling as well as spatial patterns of throughfall (TF) in abandoned Japanese cypress (Chamaecyparisobtusa) plantations remain poorly documented. In this study, gross precipitation (PG), stemflow (SF), and TFwere monitored in an unmanaged 32-year-old Japanese cypress stand throughout the 2011 rainy season. Results indicate that PGpartitioning into TF, SF, and Eiwere, respectively, 64.2 ± 3.6, 10.6 ± 0.6, and 25.2 ± 1.1 % of the 880.8 mm cumulative PGfrom 29 rainfall events. Direct throughfall proportion (p) and drainage from the canopy contributed about 14 ± 7 and 50 ± 21 % of the total TFfor the events, respectively. The mean canopy storage capacity (S) was 2.4 ± 0.7 mm. The coefficient of variability (CV) of TFrate decreased asymptotically with increasing PGamount, ranging from 16 to 56 % with median 26 %. The CV of TFrate was not significantly correlated with canopy cover (r= 0.152, P= 0.521, n= 20) and distance from the nearest trunk (r= 0.196, P= 0.408, n= 20). Based on the revised Gash analytical model, the total simulated Eiwas close to the observed, with a general underestimation magnitude of 5.7 %. The Eicomponents were quantified, and most of the interception loss (62.9 %) evaporated during rainfall, while 26.8 % evaporated after rainfall ceased. Climatic and forest structural parameters required by the model were identified and analyzed by sensitivity analysis, implying that the revised Gash analytical model is robust and reliable enough for abandoned Japanese cypress plantations in a maritime climate.

Interception loss (Ei) in forests has been studied widely. However, Eiparameters and modeling as well as spatial patterns of throughfall (TF) in abandoned Japanese cypress (Chamaecyparisobtusa) plantations remain poorly documented. In this study, gross precipitation (PG), stemflow (SF), and TFwere monitored in an unmanaged 32-year-old Japanese cypress stand throughout the 2011 rainy season. Results indicate that PGpartitioning into TF, SF, and Eiwere, respectively, 64.2 ± 3.6, 10.6 ± 0.6, and 25.2 ± 1.1 % of the 880.8 mm cumulative PGfrom 29 rainfall events. Direct throughfall proportion (p) and drainage from the canopy contributed about 14 ± 7 and 50 ± 21 % of the total TFfor the events, respectively. The mean canopy storage capacity (S) was 2.4 ± 0.7 mm. The coefficient of variability (CV) of TFrate decreased asymptotically with increasing PGamount, ranging from 16 to 56 % with median 26 %. The CV of TFrate was not significantly correlated with canopy cover (r= 0.152, P= 0.521, n= 20) and distance from the nearest trunk (r= 0.196, P= 0.408, n= 20). Based on the revised Gash analytical model, the total simulated Eiwas close to the observed, with a general underestimation magnitude of 5.7 %. The Eicomponents were quantified, and most of the interception loss (62.9 %) evaporated during rainfall, while 26.8 % evaporated after rainfall ceased. Climatic and forest structural parameters required by the model were identified and analyzed by sensitivity analysis, implying that the revised Gash analytical model is robust and reliable enough for abandoned Japanese cypress plantations in a maritime climate.

The 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released large amounts of radioactive materials into the environment. River systems play an important role in the terrestrial redistribution of FDNPP‐derived 137Cs in association with water and sediment movement. We examined the seasonal fluctuations in dissolved and particulate 137Cs activity concentrations and clarified the biological and physicochemical factors controlling 137Cs seasonality in the Abukuma River's middle course in the region affected by the FDNPP accident. The results showed seasonal fluctuations in the dissolved 137Cs activity concentration, with an increase in summer and a decrease in winter, although there was no clear seasonal change in the particulate 137Cs activity concentration. Water temperature and K+concentration dominated the seasonality of the dissolved 137Cs activity concentration. The volumetric activity concentration of the organically bound 137Cs was found to be several orders of magnitude lower than that of the dissolved 137Cs. Therefore, we concluded that the 137Cs in organic matter is not a source of dissolved 137Cs in river water. The study also revealed the temperature dependence of Kdin riverine environments from a Van't Hoff equation. The standard reaction enthalpy of 137Cs in the Abukuma River was calculated to be approximately −19.3 kJ/mol. This was the first study to clearly reveal the mechanisms by which the dissolved 137Cs activity concentration and Kdare influenced by chemical and thermodynamic processes in the middle course of a large river, and it is expected to lead to an improved model of 137Cs dynamics in rivers. The 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released large amounts of radioactive materials into the environment. River systems play an important role in the terrestrial redistribution of FDNPP‐derived 137Cs in association with water and sediment movement. The dissolved 137Cs activity concentration in the Abukuma River showed clear seasonal fluctuations, with an increase in summer and a decrease in winter, although there was no clear seasonal change in the particulate 137Cs activity concentration. Water temperature and K+concentration dominated the seasonality of the dissolved 137Cs activity concentration. Previously, decomposition of 137Cs‐contaminated organic matter was thought to be the reason for the seasonality of the dissolved 137Cs activity concentration in rivers. However, in the middle course of the river, the organically bound 137Cs activity concentration is much lower than that of the dissolved 137Cs activity concentration, indicating that the decomposition of organic matter does not directly affect the dissolved 137Cs in the middle course. This study revealed that seasonal fluctuations in river temperature determine the seasonality of the dissolved 137Cs activity concentration in the middle course in the region affected by the FDNPP accident. Dissolved 137Cs in the Abukuma River displays significant seasonal fluctuationsThe main factors determining the seasonality of dissolved 137Cs activity concentrations are water temperature and K+The standard enthalpy of 137Cs desorption from sediments was determined to be approximately −19.3 kJ/mol Dissolved 137Cs in the Abukuma River displays significant seasonal fluctuations The main factors determining the seasonality of dissolved 137Cs activity concentrations are water temperature and K+ The standard enthalpy of 137Cs desorption from sediments was determined to be approximately −19.3 kJ/mol

Abstract: To determine the effects of the characteristics of litter and surface soil on the infiltration capacity in bamboo groves, infiltration rates were measured on a plot-scale using an oscillating-nozzle rainfall simulator at seven Moso bamboo (Phyllostachys pubescens) sites and one Madake (P. bambusoides) site in Japan. The maximum final infiltration rate (FIRmax), which was defined in this study as the infiltration capacity, was calculated, and the correlation between FIRmax and earth surface properties was analyzed. The FIRmax ranged from 9 to 308 mm h−1, showing little correlation with litter as surface cover, and a weak correlation with bulk density (0.3–0.9 g cm−3) and organic matter content (10.4–45.9%). These results suggest that the bulk density and organic matter content of surface soil, rather than surface cover, can be the controlling factors of infiltration capacity in bamboo groves. The bulk density of surface soil correlated significantly with the soil organic matter content, represented by bamboo rhizomes, suggesting that the infiltration capacity can increase with the amount of root networks present, related to macropore formation. The stand density showed a weak positive correlation, although not significant, with the soil organic matter content and a positive correlation with FIRmax. Thus, the infiltration capacity of bamboo groves can increase as the stand density of culms and bamboo rhizomes increase.

AbstractTo determine the effects of the characteristics of litter and surface soil on the infiltration capacity in bamboo groves, infiltration rates were measured on a plot-scale using an oscillating-nozzle rainfall simulator at seven Moso bamboo (Phyllostachys pubescens) sites and one Madake (P. bambusoides) site in Japan. The maximum final infiltration rate (FIRmax), which was defined in this study as the infiltration capacity, was calculated, and the correlation between FIRmaxand earth surface properties was analyzed. The FIRmaxranged from 9 to 308 mm h−1, showing little correlation with litter as surface cover, and a weak correlation with bulk density (0.3–0.9 g cm−3) and organic matter content (10.4–45.9%). These results suggest that the bulk density and organic matter content of surface soil, rather than surface cover, can be the controlling factors of infiltration capacity in bamboo groves. The bulk density of surface soil correlated significantly with the soil organic matter content, represented by bamboo rhizomes, suggesting that the infiltration capacity can increase with the amount of root networks present, related to macropore formation. The stand density showed a weak positive correlation, although not significant, with the soil organic matter content and a positive correlation with FIRmax. Thus, the infiltration capacity of bamboo groves can increase as the stand density of culms and bamboo rhizomes increase.

Abstract: A low-cost and simple monitoring method for early warning of landslides is proposed. To detect abnormal deformation of a slope, this method employs a tilt sensor in place of an extensometer on the slope surface. In order to examine the relevance of measuring rotation angle on a slope surface by tilt sensor, model tests were conducted, and rotation on the slope surface was observed together with slide displacement along the surface. The rotation data responded 30 min before failure in a model test, which could be useful as a signal for early warning. However, the behavior of rotation before failure varies from case to case, and thus, criteria to issue warning should be defined more carefully. For a model slope made of uniform loose sand, measurement of slide displacement along the slope surface is sensitive to failure at the toe, while the measurement of rotation on the slope surface is useful to detect the development of progressive failure upward along the slope. Wireless sensor units with microelectromechanical systems (MEMS) tilt sensor and volumetric water content sensor were also examined on a real slope in Kobe City, and a long-term monitoring was attempted. A simple but possible way to define the criteria of judgment to issue warning can be proposed based on combination of data obtained by the tilt sensors and volumetric water content sensors.

In order to elucidate the nutrient dynamics in lakes with special reference to sediments, the changes in vertical distributions of sediment nutrients over 20 years were analyzed with the aid of sediment dating at the centers of two shallow, eutrophic lakes in Japan, i.e.Lakes Kasumigaura and Suwa. Peaks of137 Cs and apparent density gave estimated sedimentation rates of around 1 and 2 kg m-2 y-1 in Lakes Kasumigaura and Suwa, respectively. Slight decreases of TP and TN contents (0.07 and 0.63 mg g-1 for TP and TN, respectively, in Lake Kasumigaura and 0.90 mg g-1 for TN in Lake Suwa) were observed by comparison between the cores obtained around 1980 and those of recent years except for a considerable decrease in TP in Lake Suwa (1.0 mg g-1). This decrease probably came from the higher percentage of easily releasable phosphorus in the past sediments of Lake Suwa. Using the TP and TN increases in lake waters during summer, the averaged nutrient release rates were estimated to be within the ranges of those observed by laboratory core experiments and by measuring the vertical profi les of interstitial concentrations except for a smaller estimation of TN in Lake Kasumigaura. On the other hand, the nutrient release rates were also determined using the long-term changes in sediment nutrient contents. The estimated rates were a little lower than the rates determined by the method using the increase in lake nutrient concentrations other than the higher ones for TP in Lake Suwa, which were originally based on the higher percentage of easily releasable phosphorus as mentioned above. Net sedimentation rates for 24 years in Lake Kasumigaura and those for 26 years in Lake Suwa calculated as the sum of new sedimentation and changes in old sediments during these periods were compared with the net input loads based on the per capita/exporting method. In the case of TP, we observed a fairly good agreement because of its conservation, whereas the residuals were larger for TN due to denitrifi cation in the overlying waters of sediments. The rates estimated from the imbalances in TN were in the ranges of the measured denitrifi cation rates in laboratory tests with the sediments. Thus, the information on the long-term changes in sediment nutrients could provide the average rates of these fundamental processes in lake environments.

The effects of the burrowing activity of river crabs on subsurface water movement and piping erosion were studied through a flume experiment. Cohesive field soil was used and constant fluvial head was applied. During the experiments with river crabs, burrows were excavated downwards under the groundwater level. At the outlet of each burrow, the crabs excavated pellets of soil and stacked them in piles, in the form of cone mounds. These mounds acted as effective dams for subsurface outflow, but they sometimes collapsed. The roofs of the burrows also caved in occasionally, whereby the crabs would excavate new burrows. The burrowing activity of the crabs led to marked erosion. In contrast, no marked erosion was observed in experiments without crabs, indicating that piping erosion occurs through the assistance of burrowing activity. It was observed that burrowing activity and piping erosion was pronounced when the hydraulic head was not significantly high (0.21–0.25). Analysis of the potential distribution of the soil mass indicated that the head loss close to the burrow was small in the case of experiments with crabs. This suggests that the burrow enhances rapid discharge of subsurface water. Consequently, burrowing activity was found to play an important role in piping erosion and rapid discharge of subsurface water.

Zwischen den Verwitterungsraten, den hydrologischen Prozessen, Hangrutschen, der Tiefe des Verwitterungsmantels und der Hangform wurde eine Rückkopplung gefunden in vier Einzugsgebieten der Obara-Region, Zentral-Japan. Die Hänge im Granodiorit haben eine geringe Anzahl von flachen Rutschen, konvexe Profile und einen dicken Verwitterungsmantel mit hoher Wasserspeicher-Kapazität. Im Gegensatz dazu haben die Hänge im Granit eine hohe Zahl von Rutschen, ein konkaves Profil und einen dünnen Verwitterungsmantel mit geringer Wasserhaltefähigkeit. Weil der Verwitterungsmantel als ein Niederschlagsreservoir wirkt, kontrolliert er den Abfluß, seine eigene Aufnahmefähigkeit bis zur Sättigung und das Auftreten von Hangrutschen, während seine Mächtigkeit von der Abtragung durch Hangrutsche kontrolliert wird. Hangrutsche sind verantwortlich für eine konkave Hangform, während die kontinuierliche Abtragung durch Sickerung die konvexe Hangform bedingt, wo Rutschprozesse nicht dominieren.

Placental alkaline phosphatase (PLAP) is an abundant surface antigen in the malignancies of the female reproductive tract. Nevertheless, the discovery of PLAP-specific small organic ligands for targeting applications has been hindered by ligand cross-reactivity with the ubiquitous tissue non-specific alkaline phosphatase (TNAP). In this study, we used DNA-encoded chemical libraries to discover a potent (IC50= 32 nM) and selective PLAP inhibitor, with no detectable inhibition of TNAP activity. Subsequently, the PLAP ligand was conjugated to fluorescein; it specifically bound to PLAP-positive tumors in vitroand targeted cervical cancer in vivoin a mouse model of the disease. Ultimately, the fluorescent derivative of the PLAP inhibitor functioned as a bispecific engager redirecting the killing of chimeric antigen receptor-T cells specific to fluorescein on PLAP-positive tumor cells.