Genotoxic potentials and related mechanisms of bisphenol A and other bisphenol compounds: A comparison study employing chicken DT40 cells

Bisphenol A (BPA) has been found in plastic food containers, paper currencies and toys. BPA has been reported for various adverse health concerns including reproduction, development and carcinogenesis. These potential health implications have led to increasing use of alternative bisphenols such as bisphenol F and bisphenol S among many. However, little is known about the toxicity of alternative bisphenols and most of the toxicological information is limited to endocrine disrupting potentials. In this study, we evaluated cytotoxicity and the genotoxic potentials of several bisphenol compounds, and identified the mechanism of genotoxicity using a panel of mutant chicken DT40 cell lines deficient in DNA repair pathways. Several bisphenols including bisphenol AP, bisphenol M, or bisphenol P exerted genotoxic potentials that are greater than that of BPA. Generally RAD54^−/− mutant cells were the most sensitive to all bisphenols except for bisphenol F, suggesting the induction of DNA double-strand breaks that could be rescued by homologous recombination. Genotoxic potential of bisphenols was confirmed by chromosomal aberration assay and γ-H2AX foci forming assay between wild-type and RAD54^−/− mutant. Among the tested bisphenols, BPP at 12.5 μM showed the greatest genotoxic potency, inducing chromosomal aberration and γ-H2AX foci in RAD54^−/− mutant by 2.6 and 4.8 folds greater than those in wild-type, respectively. Our results clearly show several alternative bisphenols can cause genotoxicity that could be rescued by homologous recombination pathway, and some bisphenols induced even greater genotoxic potentials than that of BPA.     

Validation of diffusive mini-samplers for aldehyde and VOC and its feasibility for measuring the exposure levels of elementary school children

Exposure to various chemicals can cause adverse effects to health, such as asthma and allergies, especially in children. Data on personal exposure levels in children are scarce, thus small lightweight diffusive mini-samplers for aldehydes and volatile organic compounds (VOCs) were designed to measure the exposure level of children to these chemicals. The aim of the study was to validate and examine the applicability of these mini-samplers for measuring daily chemical exposure. The diffusive mini-samplers are 20 mm in length, 11 mm in diameter, and 1.67 g in weight. The devices are cylindrically shaped with polytetrafluoroethylene membrane filters placed at each end. To measure aldehydes and acetone, 20 mg of 2,4-dinitrophenylhydrazine was used as an absorbent. To measure VOCs, a carbon molecular sieve was used. The sampling rate for each chemical was determined by parallel sampling with active samplers in a closed exposure bag. The blank levels of the chemicals and the storage stability of the device were tested. The mini-samplers were compared to commercially available diffusive samplers. To examine the applicability of the samplers, 65 elementary school children carried them for 24 h. The sampling rates for formaldehyde, acetaldehyde, and acetone were 20.9, 22.9, and 19.7 mL min(-1), respectively. The limits of quantification (LOQ) for the 24-hour sampling by high-performance liquid chromatography/ultraviolet (HPLC/UV) analysis were 8.3, 7.6, and 8.8 μg m(-3) for formaldehyde, acetaldehyde, and acetone, respectively. The sampling rates for the 11 VOCs were determined and ranged from 3.3 mL min(-1) for styrene and 2-ethyl-1-hexanol to 11.7 mL min(-1) for benzene. The LOQ for the 24-hour sampling by gas chromatography-mass spectrometry (GC-MS) analysis ranged from 5.9-105.2 μg m(-3), 1.1-24.7 parts per billion. The storage stability after 5 days ranged from 94.8 to 118.2%. Formaldehyde, acetone, benzene, and toluene were detected above the LOQ in more than 90% of the children, and the median concentrations were 21.7, 20.9, 10.1, and 21.5 μg m(-3), respectively. This study shows that the diffusive samplers developed were suitable for children to carry and were capable of measuring the children's daily chemical exposure.     

Production of 2-Pyrrolidone from Biobased Glutamate by Using Escherichia coli

We have developed a simple and highly efficient process for the production of 2-pyrrolidone (2-PRN) from biobased l-glutamic acid (Glu). First, we produced γ-aminobutyric acid (GABA) from Glu obtained by fermentation of biomass using Escherichia coli, which is known to possess GABA producing activity. The reaction solution contained only the substrate Glu, bacterial cells, and water, and did not require buffers or coenzymes, pyridoxal-5′-phosphate (PLP). Every 24 h, cells were removed by centrifugation, and GABA containing supernatant was obtained. This reaction can be repeated 14 times by adding water and Glu, without any decrease in activity. Finally, 303.7 g of GABA was produced from 560 g (40 g × 14 times) of Glu with a yield of 77.4 %. The concentration of this solution was almost 40 %. The GABA was then converted to biobased 2-PRN by heating and distillation under reduced pressure without pretreatment. The yield obtained with this chemical process was 95.8 %. These results showed that biobased 2-PRN could be produced from biomass-derived Glu. Biobased 2-PRN has great potential as a raw material to change other petroleum-based materials to biobased materials.     

Vulnerability, Risk and Adaptation Assessment Methods in the Pacific Islands Region: past approaches, and considerations for the future

Over two decades of vulnerability assessments have shown the Pacific Islands region to be one of the regions most at risk to the adverse consequences of climate change. Pacific Island countries have shown strong leadership in characterising the challenges of climate change, both nationally and for the region as a whole, and in identifying the most appropriate responses. This paper reviews the various Vulnerability, Risk and Adaptation (VRiA) Assessment Methods and Tools that have been used across the Pacific Islands region, with an emphasis on the past two decades. The aim is to identify the approaches that are best suited to the region, and to develop a common understanding and principles that may be relevant and useful to harmonising the assessment of vulnerability and risk, and of adaptation options across the region. Even though assessments undertaken in the Pacific Islands region tend to share the common objective of reducing vulnerabilities and risks, practitioners in the Pacific are using numerous approaches, methods and tools to assess vulnerabilities and identify possible adaptation interventions. No one approach will address all needs and accommodate all capacities. Rather, several successful approaches, methods and tools are identified. The paper also identifies and assesses the approaches, methods and tools that have merit for further use, without or with further improvements. Lessons learned as well as success stories and success factors are documented. These findings are reflected in principles designed to assist harmonisation of approaches to VRiA assessment. These principles, in turn, influence the development of a proposed higher-level framework and approach for VRiA assessments. It accommodates the various approaches, methods and tools commonly used with success in the Pacific.     

Accumulation of Hg and other heavy metals in the Javan mongoose (Herpestes javanicus) captured on Amamioshima Island, Japan

Concentrations of 22 elements (Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, total Hg (T-Hg), Pb) and organic Hg (O-Hg) were examined in the liver, kidney and brain of the Javan mongoose (Herpestes javanicus) and in liver of the Amami rabbit (Pentalagus furnessi) from Amamioshima Island in Japan. Relatively high levels of T-Hg levels (from 1.75 to 55.5 microg g-1 wet wt.) were found in the Javan mongoose. As for a comparison of hepatic T-Hg concentrations between the two areas, there was no significant difference between the Javan mongoose in Amamioshima and those in the Okinawa islands. In addition, T-Hg levels in the livers of the Amami rabbit were the same as in the livers of other herbivorous mammals. Taken together, it suggested that T-Hg accumulation in the livers of the Javan mongoose was not affected by the environment but by a specific physiological mechanism. The comparison of Hg and other heavy metal accumulations between terrestrial mammals (13 species, 61 individuals) including the Javan mongoose and marine mammals (18 species, 508 individuals) were also discussed.     

Uptake and distribution of iodine in rice plants

Rice (Oryza sativa L.) plants were cultivated in an experimental field and separated at harvest into different components, including polished rice, rice bran, hull, straw, and root. The contents of iodine in these components and the soil were determined by inductively coupled plasma-mass spectrometry and radiochemical neutron activation analysis, respectively. Iodine content varied by more than three orders of magnitude among the plant components. Mean concentration of iodine in the entire plants was 20 mg kg(-1) dry weight, and the concentration of iodine in the surface soil (0-20 cm depth) was 48 mg kg(-1). The highest concentration of iodine (53 mg kg(-1) dry weight) was measured in root and the lowest concentration (0.034 mg kg(-1) dry weight) in polished rice. While the edible component (polished rice) accounted for 32% of the total dry weight, it contained only 0.055% of iodine found in the entire rice plants. Atmospheric gaseous iodine (5.9 ng m(-3)) was estimated to contribute <0.2% of the total iodine content in the biomass of rice plants; therefore nearly all of the iodine in the rice plants was a result of the uptake of iodine from the soil. The content of iodine in the aboveground part of rice plants was 16 mg kg(-1) dry weight and the percentage of iodine transferred per cropping from the soil into the aboveground biomass corresponded to 0.27% (20 mg m(-2)) of the upper soil layer content.     

Inundation Analysis in the Coastal Area Considering Climate Change Due to Global Warming

This paper describes the possible inundation scenarios under sea level rise conditions due to global climate change with particular reference to Nagoya, Japan. The study was carried out by using a two-dimensional sea model integrated with one-dimensional river flow model and two-dimensional overland flow model. For the connections of models, the upstream discharge or downstream water level in each grid is considered as the boundary conditions. The governing equations used for the analysis have been solved by finite volume method. The analysis results implicate that some parts of densely populated coastal area of Nagoya city will be vulnerable to inundation if the sea level rise due to global warming by 1 m. Moreover, the performances of existing sewer system and inundation scenario under various conditions have been analyzed.     

Creating an academic landscape of sustainability science: an analysis of the citation network

Sustainability is an important concept for society, economics, and the environment, with thousands of research papers published on the subject annually. As sustainability science becomes a distinctive research field, it is important to define sustainability clearly and grasp the entire structure, current status, and future directions of sustainability science. This paper provides an academic landscape of sustainability science by analyzing the citation network of papers published in academic journals. A topological clustering method is used to detect the sub-domains of sustainability science. Results show the existence of 15 main research clusters: Agriculture, Fisheries, Ecological Economics, Forestry (agroforestry), Forestry (tropical rain forest), Business, Tourism, Water, Forestry (biodiversity), Urban Planning, Rural Sociology, Energy, Health, Soil, and Wildlife. Agriculture, Fisheries, Ecological Economics, and Forestry (agroforestry) clusters are predominant among these. The Energy cluster is currently developing, as indicated by the age of papers in the cluster, although it has a relatively small number of papers. These results are compared with those obtained by natural language processing. Education, Biotechnology, Medical, Livestock, Climate Change, Welfare, and Livelihood clusters are uniquely extracted by natural language processing, because they are common topics across clusters in the citation network.     

Ocean fertilization for geoengineering: A review of effectiveness,environmental impacts and emerging governance

Dangerous climate change is best avoided by drastically and rapidly reducing greenhouse gas emissions. Nevertheless, geoengineering options are receiving attention on the basis that additional approaches may also be necessary. Here we review the state of knowledge on large-scale ocean fertilization by adding iron or other nutrients, either from external sources or via enhanced ocean mixing. On the basis of small-scale field experiments carried out to date and associated modelling, the maximum benefits of ocean fertilization as a negative emissions technique are likely to be modest in relation to anthropogenic climate forcing. Furthermore, it would be extremely challenging to quantify with acceptable accuracy the carbon removed from circulation on a long term basis, and to adequately monitor unintended impacts over large space and time-scales. These and other technical issues are particularly problematic for the region with greatest theoretical potential for the application of ocean fertilization, the Southern Ocean. Arrangements for the international governance of further field-based research on ocean fertilization are currently being developed, primarily under the London Convention/London Protocol.     

Mercury emission from sewage sludge incineration in Japan

Sewage sludge contains trace amounts of mercury, and sewage sludge incineration is a major source of mercury emissions. However, relatively few studies have reported on mercury emissions from sewage sludge incineration. Consequently, data on emissions from sewage sludge incinerators must be updated to estimate current emissions of mercury. In this study, we examined mercury emissions and speciation using continuous mercury analyzers in two incinerators. The mercury concentrations in stack gas from facilities A and B were 36.6 and 21.1???g/Nm³, respectively. As a result, the emission rate was calculated to be 0.282?C0.750?g/ton-dry sludge. Considering the total amount of sewage sludge incinerated in Japan, the mercury emissions from sewage sludge incinerators were estimated to be 0.49?C1.31?tons/year.