Plutonium concentration and 240Pu/239Pu atomic ratio in liver of squid collected in the coastal sea areas of Japan

Plutonium isotopes, 239Pu and 240Pu, were measured in liver samples from Surume squid using a sector-field high resolution ICP-MS after radiochemical purification. Surume squid samples were obtained from nine landing ports in Japanese inshore during fishery season from September to December 2002. Concentrations of 239Pu and 240Pu ranged from 1.5 to 28 mBq kg(-1) and 1.1 to 24 mBq kg(-1), respectively. Plutonium (239,240Pu) concentrations in liver were several thousand times higher than levels found in seawater. The concentration factor (CF) compared to seawater for 239,240Pu and 13 other elements ranged from 10(0) to 10(7). The CF values for 239,240Pu, V and Th were 10(2)-10(4). Pu had an intermediate CF between conservative and scavenged elements. 240Pu/239Pu atomic ratios in the squid liver ranged from 0.177 to 0.237 which were slightly higher than 0.178+/-0.014 for global fallout. The variations of 240Pu/239Pu atomic ratios in ocean currents with different source functions are important for interpreting high 240Pu/239Pu atomic ratios in Surume squid liver. It seems likely that Pu with high 240Pu/239Pu atomic ratio is continuously transported through the solubilization and seawater transport from the North Equatorial Current to Kuroshio and its branch, Tsushima Current. By assuming that Pu found in Surume squid liver is a mixture of global fallout Pu (0.178) and close-in fallout Pu with high 240Pu/239Pu atomic ratio (0.30-0.36) around Bikini Atoll, Pu contribution from Bikini close-in fallout Pu accounts for close to 35% of the whole plutonium in Surume squid liver. These results highlight that Surume squid is a useful organism for evaluating environmental Pu levels of larger sea area and facilitate the development of models to understand oceanic transport of close-in fallout Pu from Bikini Atoll.     

Inventories of Pu, Cs, and excess Pb in sediments from freshwater and brackish lakes in Rokkasho, Japan, adjacent to a spent nuclear fuel reprocessing plant

We investigated the vertical profiles of ^239+240Pu, ¹³⁷Cs, and excess ²¹⁰Pb (²¹⁰Pb_ex) in sediment core samples obtained from two freshwater lakes and two brackish lakes situated near the first commercial spent nuclear fuel reprocessing plant in Rokkasho, Japan, before the final test of the plant using actual spent nuclear fuel. The inventory of ^239+240Pu in those lakes was larger than that in soil in Rokkasho, which indicated the inflow of ^239+240Pu from the catchment area in addition to direct deposition on the lake surfaces. The ¹³⁷Cs inventory in sediments of the brackish lakes was lower than that in the soil, which showed that part of the ¹³⁷Cs was removed from the sediments by the brackish water or that it was not deposited into the sediments, because of the high solubility of Cs in brackish water. The ¹³⁷Cs inventory in sediments of the freshwater lakes was higher than that of the brackish lakes, and comparable with that in soil except for one core sample out of four. The ^239+240Pu/¹³⁷Cs ratio in freshwater lake sediments was higher than that in soil, and that indicated that part of the ¹³⁷Cs was lost from the sediments. The low inventory of ¹³⁷Cs may be attributable to competition for absorption sites in sediments with ammonium ions formed in the reducing environment which occurs from summer to fall in the sediments. Those data will be used as background data on the artificial radionuclides in the lakes to assess the effect of released radionuclides on their concentrations.     

Isolation and identification of new vasodilative substances in diesel exhaust particles

Background, aim, and scope  

We recently developed a new isolation method for diesel exhaust particles (DEP), involving successive extraction with H₂O, sodium bicarbonate, and sodium hydroxide, in which the sodium hydroxide extract was found to consist of phenolic components. Analysis of the extract revealed that vasodilative-active nitrophenols are in DEP in significantly higher concentrations than those estimated by an earlier method involving a combination of solvent extraction and repeated chromatography. These findings indicated that our new procedure offers a simple, efficient, and reliable method for the isolation and identification of bioactive substances in DEP. This encouraged us to extend our work toward investigating new vasodilatory substances in the sodium bicarbonate extract.     

Occurrence of tributyltin (TBT)-resistant bacteria is not related to TBT pollution in Mekong River and coastal sediment: with a hypothesis of selective pressure from suspended solid

Tributyltin (TBT) is organotin compound that is toxic to aquatic life ranging from bacteria to mammals. This study examined the concentration of TBT in sediment from and near the Mekong River and the distribution of TBT-resistant bacteria. TBT concentrations ranged from <2.4 to 2.4 ng/g (dry wt) in river sediment and <2.4-15 ng g(-1) (dry wt) in harbor sediment. Viable count of total bacteria ranged from 2.0 x 10(4) to 1.4 x 10(7)cfu/g, and counts of TBT-resistant bacteria ranged <1.0 x 10(2) to 2.5 x 10(4)cfu/g. The estimated occurrence rate of TBT-resistant bacteria ranged from <0.01 to 34% and was highest in upstream sites in Cambodia. The occurrences of TBT in the sediment and of TBT-resistant bacteria were unrelated, and chemicals other than TBT might induce TBT resistance. TBT-resistant bacteria were more abundant in the dry season than in the rainy season. Differences in the selection process of TBT-resistant bacteria between dry and rainy seasons were examined using an advection-diffusion model of a suspended solid (SS) that conveys chemicals. The estimated dilution-diffusion time over a distance of 120 km downstream from a release site was 20 days during dry season and 5 days during rainy season, suggesting that bacteria at the sediment surface could be exposed to SS for longer periods during dry season.     

Degradation of Poly(acrylic acid)s with Phenolic Side-Chains by Manganese Peroxidase from White Rot Fungi

Poly(acrylic acid)s (PAAs) with various functional groups, such as phenolic hydroxyl, amino, and aldehyde groups, in the side-chains were treated with manganese peroxidase (MnP) prepared from the culture of lignin-degrading white rot fungi. While no change in the M_w of PAA without a functional group was observed after a 24-h MnP treatment, the M_w␣of␣PAA␣with p-aminophenol as side-chains decreased from 90,000 to 59,000, and that with␣o-aminophenol from 70,000 to 26,000. MnP treatment also decreased the M_w of PAA with a p-aminoaniline or aldehyde group. Furthermore, the MnP treatment generated a significant depolymerization of the cross-linked PAA with p-aminophenol from an insoluble polymer to water soluble products. These results suggest that functional groups generating radicals can act as elemental devices and induce degradation of the PAA main chain.     

The literature landscape on peace–sustainability nexus: A scientometric analysis

Academics, policymakers, and practitioners have long considered peace and sustainability to be fundamentally linked. However, despite the increased attention paid toward the intersection of peace and sustainability, there is still limited knowledge on the nature of their linkages. To advance the current understanding on the peace–sustainability nexus and inform an integrated research agenda, this paper employs a scientometric analysis of literature to identify publication trends, thematic clusters, and knowledge gaps. Analyzing the publications according to the types of peace, the pillars of positive peace, the dimensions of sustainability, and the SDGs further reveals weak engagement among academic disciplines and across the SDGs. The results of this analysis emphasize the need for future research to focus on underexamined subjects, geographic regions, and sectors to bolster the linkages between peace and sustainability.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01388-8) contains supplementary material, which is available to authorized users.     

Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida)

Platydemus manokwari is a broadly distributed invasive terrestrial flatworm that preys heavily on land snails and has been credited with the demise of numerous threatened island faunas. We examined whether P. manokwari tracks the mucus trails of land snail prey, investigated its ability to determine trail direction, and evaluated prey preference among various land snail species. A plastic treatment plate with the mucus trail of a single species and a control plate without the trail were placed side by side at the exit of cages housing P. manokwari. All trials were then videotaped overnight. The flatworms moved along plates with mucus trails, but did not respond to plates without trails, blank control (distilled water), or with conspecific flatworm trails. When presented at the midpoint of a snail mucus trail, the flatworms followed the trail in a random direction. The flatworms showed a preference when choosing between two plates, each with a mucus trail of different land snail species. Our results suggest that P. manokwari follows snail mucus trails based on chemical cues to increase the chance of encountering prey; however, trail-tracking behavior showed no directionality.     

A survey of indoor workplace radon concentration in Japan

Radon ((222)Rn) concentration was measured at indoor workplaces in Japan to estimate effective dose to the public from (222)Rn and its progeny. Measurements were made from 2000 to 2003 at 705 sites in four categories of office, factory, school and hospital. Passive type Rn monitors equipped with two sheets of polycarbonate thin films for measuring radon concentrations were installed at observation sites and replaced every 3 months to observe seasonal variations in (222)Rn concentrations. The range of annual mean (222)Rn concentrations for all sites was 1.4-182 Bq m(-3), with the arithmetic mean and standard deviation were 20.8 and 19.5 Bq m(-3). Annual mean (222)Rn concentration observed at office, factory, school and hospital were 22.6, 10.1, 28.4 and 19.8 Bq m(-3), respectively. Seasonal variations in (222)Rn concentrations at offices, schools and hospitals were similar to those found in dwellings, and variations in factories were similar to those found in outdoor environments. (222)Rn concentration observed in every quarter period was found to decrease as follows: school>office>hospital>factory. The average effective dose to the public due to (222)Rn was estimated to be 0.41 mSv y(-1) weighted by the working population. Considering the (222)Rn exposure in indoor workplaces, effective dose to the general public is estimated to be in the range from approximately 0.42 to 0.52 mSv y(-1).