Zinc tolerance and uptake by <Emphasis Type="Italic">Arabidopsis halleri ssp. gemmifera</Emphasis> grown in nutrient solution

Background, aim, and scope  

Zinc is an essential micronutrient element but its concentrations found in contaminated soils frequently exceed those required by the plant and soil organisms, and thus create danger to animal and human health. Phytoremediation is a technique, often employed in remediation of contaminated soils, which aims to remove heavy metals or other contaminants from soils or waters using plants. Arabidopsis (A.) halleri ssp. gemmifera is a plant recently found to be grown vigorously in heavy metal contaminated areas of Japan and it contained remarkably high amount of heavy metals in its shoots. However, the magnitude of Zn accumulation and tolerance in A. halleri ssp. gemmifera need to be investigated for its use as a phytoremediation plant.     

Effects of acute γ-irradiation on the aquatic microbial microcosm in comparison with chemicals

Effects of acute γ-irradiation were investigated in the aquatic microcosm consisting of green algae (Chlorella sp. and Scenedesmus sp.) and a blue–green alga (Tolypothrix sp.) as producers; an oligochaete (Aeolosoma hemprichi), rotifers (Lecane sp. and Philodina sp.) and a ciliate protozoan (Cyclidium glaucoma) as consumers; and more than four species of bacteria as decomposers. At 100 Gy, populations were not affected in any taxa. At 500–5000 Gy, one or three taxa died out and populations of two or three taxa decreased over time, while that of Tolypothrix sp. increased. This Tolypothrix sp. increase was likely an indirect effect due to interspecies interactions. The principal response curve analysis revealed that the main trend of the effects was a dose-dependent population decrease. For a better understanding of radiation risks in aquatic microbial communities, effect doses of γ-rays compared with copper, herbicides and detergents were evaluated using the radiochemoecological conceptual model and the effect index for microcosm.     

Solventless Delignification of Wood Flour with TiO2/poly(ethylene oxide) Photocatalyst System

A novel solventless delignification of a defatted Picea glehnii wood flour sample was performed using a TiO₂/polyethylene oxide (PEO) photocatalyst system. A cell wall structure of the wood flour was directly observed, showing that its lignin fraction was removed by the photodegradation. The total lignin amount was slightly decreased as compared with that of the pristine sample, and the vanillin formation was confirmed by the ¹H-NMR measurement. The TiO₂ worked as a radical initiator, and simultaneously acid and aldehyde compounds produced by the PEO photolysis did as an accelerator for the solventless delignification. Although the photocatalyst system showed high delignification activity even for a low molecular lignin model, the delignification of the wood flour sample was confined to the surface. It was found that the suppressed delignification behavior was due to crosslinked structure of lignin.     

Recovery of gold by chicken egg shell membrane-conjugated chitosan beads

We have successfully prepared a bead-type adsorbent from two materials with different adsorption characteristics. Heavy metals were removed by greatly swollen egg shell membrane-conjugated chitosan beads. The egg shell membrane accumulated and removed precious metal ions from a dilute aqueous solution with a high affinity in a short contact time. Experiments suggested that chitosan beads could take up gold ions with great capacity and selectivity by conjugation with egg shell membrane. Under certain conditions, the selective removal of gold and copper in a mixture of gold and copper ions by egg shell membrane-conjugated chitosan beads was 100% and 2%, respectively. Egg shell membrane-conjugated chitosan beads can be seen as a promising material to recover gold in wastewater from various industries, such as electroplating.     

Preparation and Characterization of Cellulose/Polypropylene Composite Using an Oxidatively Degraded Polypropylene

In this work, an oxidatively degraded polypropylene (DgPP) was studied as a novel coupling agent for fibrous cellulose (FC)/polypropylene (PP) composite. An optimal preparation time of PP thermal oxidative degradation was 18 h at 130 °C, and the DgPP had functional groups such as γ-lactone and acid groups. The spherulite observation of the DgPP suggested miscibility for the undegraded PP. The addition of the DgPP presented the transparency improvement of FC/PP composite, and this behavior was found to be originated from the grafted DgPP, which was produced by the esterification reaction between the of FC and the DgPP. The scanning electron microscope (SEM) observation showed that the grafted DgPP coated the FC surface, and the tensile strength of the FC/PP composite increased by an appropriate amount of the DgPP addition. These results suggested that the DgPP was suitable for the coupling agent of FC/PP composite.     

Economic evaluation of sewage treatment processes in India

This paper evaluates the total annual cost including capital and operation and maintenance (O&M) costs for the up-flow anaerobic sludge blanket (UASB) and waste stabilization pond (WSP) systems operated in India. It also compares UASB and WSP systems with the activated sludge process (ASP) and biological aerated filter (BAF) systems in terms of total annual cost and chemical oxygen demand (COD) removal cost by assuming various annual interest rates and land prices. It was found that the relationship between capital and O&M costs per unit size of a UASB or WSP system and its treatment capacity can be established by a first-order equation. The relation between the cost of organic removal and capital or O&M cost for various sewage treatment systems at various annual interest rates revealed that, for the Indian context, UASB could be the most suitable option in terms of expenses and treatment efficiency.     

Infectious waste management in Japan: a revised regulation and a management process in medical institutions

In Japan, the waste management practice is carried out in accordance with the Waste Disposal Law of 1970. The first rule of infectious waste management was regulated in 1992, and infectious wastes are defined as the waste materials generated in medical institutions as a result of medical care or research which contain pathogens that have the potential to transmit infectious diseases. Revised criteria for infectious waste management were promulgated by the Ministry of Environment in 2004. Infectious waste materials are divided into three categories: the form of waste; the place of waste generation; the kind of infectious diseases. A reduction of infectious waste is expected. We introduce a summary of the revised regulation of infectious waste management in this article.     

Evolutionary relationships of deep-sea mussels inferred by mitochondrial DNA sequences

In order to elucidate the evolutionary process of deep-sea Bathymodiolus mussels, we investigated the phylogenetic relationships of 16 species worldwide by analyzing nucleotide sequences of the mitochondrial COI and ND4 genes. Deep-sea mussels were clustered into three groups by basal trichotomous divergence. The first was composed of four species found in Japanese waters and one species from the Gulf of Mexico, which contain methanotrophic endosymbiotic bacteria. The second included nine species distributed in the West and East Pacific, Indian, and Atlantic Oceans. Members of the second group were trichotomously divided into the Indo-West Pacific, Atlantic, and East Pacific subclusters. The Indo-West Pacific subcluster was composed of three very closely related species with mutual genetic distances at the intraspecific level (av. 0.019 in COI and 0.009 in ND4 relative to av. 0.156 in COI and 0.265 in ND4 among Bathymodiolus species other than Cluster A species), suggesting some gene flow among these species. The third consisted of two West Pacific species. Species in the second and third groups contain mainly thioautotrophic endosymbionts, including some species harboring both methanotrophs and thioautotrophs.     

Measurement of photosynthetic production of a marine phytoplankton population using a stable 13C isotope

The use of stable isotope of carbon, ¹³C, for the determination of the photosynthetic rate of a marine phytoplankton population was examined. Particular concern was paid to the effects of non-phytoplanktonic organic carbon and the enrichment of inorganic carbon on the estimation of the photosynthetic rate. Photosynthetic rates determined by the ¹³C method showed a remarkable agreement with those determined by the ¹⁴C method. Insitu determinations of photosynthetic rate were made in three different water types: open ocean, coastal and neritic waters, which included oligo- and mesotrophic waters, by using the ¹³C method established.