Preparation of Chitin/Cellulose Films Compatibilized with Polymeric Ionic Liquids

This paper reports the preparation of chitin/cellulose films compatibilized with polymeric ionic liquids. In-situ (co)polymerization of polymerizable ionic liquids, 1-(3-methacryloyloxypropyl)-3-vinylimidazolium bromide (1) and 1-methyl-3-vinylbenzylimidazolium chloride (3), was carried out in the presence of a radical initiator, AIBN, in the chitin/cellulose solution with ionic liquid solvents (1-butyl-3-methylimidazolium acetate and chloride, BMIMOAc and BMIMCl, respectively), followed by the appropriate procedure to give the desired films. The presence of the polymeric ionic liquid in the film was confirmed by the IR measurement. The powder X-ray diffraction analysis suggested that crystalline structures of the polysaccharides were largely disrupted in the film, as same as that of a chitin/cellulose film prepared by the AMIMOAc/BMIMCl system. These results were different from the XRD result of a chitin/cellulose film prepared by the 1-allyl-3-methylimidazolium bromide/BMIMCl system reported in our previous study, in which some crystalline structures were still remained in the film. Furthermore, the mechanical properties of the present films were evaluated by tensile testing, which were affected by the molar ratios of the polymeric ionic liquids to the polysaccharides and the compositional ratios of the two units 1 and 3.     

Detection of Escherichia coli in a cattle manure composting process by selective cultivation and colony polymerase chain reaction

Livestock manure is suitable for use as a composting material. However, various intestinal microbes, such as Escherichia coli, are significant components of such manures. Thus, it is desirable that the level of intestinal microbes, and particularly opportunistic pathogens, in compost is inspected and counted regularly. The sensitivity and specificity of detection of E. coli in compost have been improved by selective cultivation followed by colony polymerase chain reaction (PCR) using the ECO primer. Indeed, the sensitivity of this method is higher than that of DNA extraction from compost and PCR. In this study, changes in numbers of E. coli present in a field-scale composting process over time was assessed using selective cultivation and colony PCR. Numbers of ECO-positive colonies after 24 h decreased, with a concomitant rise in compost temperature. ECO-positive colonies were not detected from 33 to 48 h. However, ECO-positive colony numbers increased beginning on day 4 and continuing until day 42. Thus, it seems likely that the high temperatures reached during the composting process did not affect E. coli numbers in the final compost. Additionally, selective cultivation followed by colony PCR using specific primers is an appropriate method of determining levels of cultivable pathogens in composted materials.     

Ecological risk assessment of TBT in Ise Bay

An ecological risk assessment of tributyltin (TBT) in Ise Bay was conducted using the margin of exposure (MOE) method. The assessment endpoint was defined to protect the survival, growth and reproduction of marine organisms. Sources of TBT in this study were assumed to be commercial vessels in harbors and navigation routes. Concentrations of TBT in Ise Bay were estimated using a three-dimensional hydrodynamic model, an ecosystem model and a chemical fate model. Estimated MOEs for marine organisms for 1990 and 2008 were approximately 0.1-2.0 and over 100 respectively, indicating a declining temporal trend in the probability of adverse effects. The chemical fate model predicts a much longer persistence of TBT in sediments than in the water column. Therefore, it is necessary to monitor the harmful effects of TBT on benthic organisms.     

Numerical investigation concerning the impact of CO2 geologic storage on regional groundwater flow

Large-scale storage of carbon dioxide in saline aquifers may cause considerable pressure perturbation and brine migration in deep rock formations, which may have a significant influence on the regional groundwater system. With the help of parallel computing techniques, we conducted a comprehensive, large-scale numerical simulation of CO₂ geologic storage that predicts not only CO₂ migration, but also its impact on regional groundwater flow. As a case study, a hypothetical industrial-scale CO₂ injection in Tokyo Bay, which is surrounded by the most heavily industrialized area in Japan, was considered, and the impact of CO₂ injection on near-surface aquifers was investigated, assuming relatively high seal-layer permeability (higher than 10 microdarcy). A regional hydrogeological model with an area of about 60 km × 70 km around Tokyo Bay was discretized into about 10 million gridblocks. To solve the high-resolution model efficiently, we used a parallelized multiphase flow simulator TOUGH2-MP/ECO2N on a world-class high performance supercomputer in Japan, the Earth Simulator. In this simulation, CO₂ was injected into a storage aquifer at about 1 km depth under Tokyo Bay from 10 wells, at a total rate of 10 million tons/year for 100 years. Through the model, we can examine regional groundwater pressure buildup and groundwater migration to the land surface. The results suggest that even if containment of CO₂ plume is ensured, pressure buildup on the order of a few bars can occur in the shallow confined aquifers over extensive regions, including urban inlands.     

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.     

Development of a testing method for asbestos fibers in treated materials of asbestos containing wastes by transmission electron microscopy

Appropriate treatment of asbestos-containing wastes is a significant problem. In Japan, the inertization of asbestos-containing wastes based on new treatment processes approved by the Minister of the Environment is promoted. A highly sensitive method for testing asbestos fibers in inertized materials is required so that these processes can be approved. We developed a method in which fibers from milled treated materials are extracted in water by shaking, and are counted and identified by transmission electron microscopy. Evaluation of this method by using asbestos standards and simulated slag samples confirmed that the quantitation limits are a few million fibers per gram and a few μg/g in a sample of 50 mg per filter. We used this method to assay asbestos fibers in slag samples produced by high-temperature melting of asbestos-containing wastes. Fiber concentrations were below the quantitation limit in all samples, and total fiber concentrations were determined as 47–170 × 10^?6 f/g. Because the evaluation of treated materials by TEM is difficult owing to the limited amount of sample observable, this testing method should be used in conjunction with bulk analytical methods for sure evaluation of treated materials.     

Characterization of iron elution for seaweed bed restoration using a steelmaking slag and compost method

Coastal areas in Japan and other parts of the world have serious problems with barren grounds. A method has been developed that uses a mixture of steelmaking slag and compost including humic substances supplied in seawater, for restoring seaweed beds. The effects of this method have been previously confirmed in field tests. It was found that the mixture of steelmaking slag and compost was effective for extending the lifetime of iron elution as well as increasing iron concentrations in seawater. In this study, the effect of the mixing composts with steelmaking slag was evaluated additionally for increasing dissolved iron concentrations in seawater. The characteristics of iron elution were also studied using this method. In particular, the mechanism of Fe elution and dissolved Fe oxidation was examined in detail. The iron elution of actual seawaters was tested using three kinds of samples which involved steelmaking slag, compost, and a mixture of steelmaking slag and compost. These samples were used to understand the mechanism of Fe elution and oxidation in seawater. It was found that the mixture of steelmaking slag and compost was the most effective, which also confirmed the validity of the proposed Fe elution process in seawater.