Functional morphology and phylogeny of the rock-boring bivalves <Emphasis Type="Italic">Leiosolenus</Emphasis> and <Emphasis Type="Italic">Lithophaga</Emphasis> (Bivalvia: Mytilidae): a third functional clade

The functional morphology of the shell of rock-boring mytilids (especially Leiosolenus and Lithophaga) is analyzed and compared with that of several epifaunal and semi-infaunal mytilids. Semi-infaunal species are generally intermediate between epifaunal and rock-boring ones both in terms of shell form and the magnitude of forces pulling the shells against the substratum. A molecular phylogenetic analyses using 18s rDNA sequence data strongly suggests that Leiosolenus and Lithophaga are monophyletic genera but that the so-called Lithophaginae (or Leiosolenus plus Lithophaga) is a paraphyletic group. The common cylindrical shell form of rock-boring species, which is here called “lithophagiform” as a third functional mytilid clade, may be due to convergence, as is the case with ‘mytiliform’ and ‘modioliform’.     

Natural purification effects in the river in consideration with domestic wastewater pollutant discharge reduction effects

The first social experiment program in Japan to reduce domestic wastewater pollutant discharge by “soft interventions” in households has been conducted in the Yamato-gawa River drainage area since 2005. The Yamato-gawa River has been listed as one of the worst water quality rivers in Japan because of the larger annual average BOD. “Hard interventions” including deployment of wastewater treatment facilities and artificial installation of natural purification facilities in the river has been conducted in these years to improve river water quality. At the first Yamato-gawa River social experiment program (YR-SEP) in March 2005, BOD at the monitoring point near the river mouth decreased about 6% during the Program. Natural purification e ect along the river was evaluated in this article with one-dimensional water quality model for the six river sections. Larger biological oxygen consumption rate, kb, was estimated in the sections with artificially installed natural purification facilities. The e ect of “soft interventions” in households in the YR-SEP was estimated as 25% BOD decrease in the nearest monitoring point to the river mouth, when all the households participate in the Program and BOD discharge reduction rate with “soft interventions” in households was 40%.     

Analysis of driving forces behind diversified carbon dioxide emission patterns in regions of the mainland of China

China has large regional disparities in carbon dioxide CO₂ emissions with economic development among its 31 provincial mainland regions. This paper investigates these disparities in CO₂ emission patterns and identifies the factors underlying the differences. Results show that the 30 study China's mainland provinces (Tibet not included) can be divided into seven groups with three typical CO₂ emission patterns. Index decomposition results indicate that changes in economic development, the industrial sector, and technology contribute far more to increased CO₂ emissions than do population, energy structure, and other sectors. Close inspection reveals that different industry structures and technology contribute greatly to the differences observed in CO₂ emissions between provinces with similar economic output. This study highlights the importance of region-specific industrial structure adjustment policies, especially for regions transitioning to heavy industry and for those still in the primary stages of industrialization. The potential application of a domestic carbon emissions trading system, to encourage regional investment in updated technology, is also discussed.     

Composition of green turtle feeding aggregations along the Japanese archipelago: implications for changes in composition with current flow

In order to develop effective conservation strategies for endangered migratory species, the link between feeding and breeding grounds needs to be clarified. In this study, the genetic compositions of consecutive Japanese feeding aggregations of green turtles (Chelonia mydas) along the Kuroshio Current were examined by mixed-stock analyses of mitochondrial DNA control-region sequences. The results indicated that the southern feeding aggregation around Yaeyama (24.3°N, 124.0°E) was sourced from various Pacific rookeries in the Yaeyama, Ogasawara, Western Pacific, and Indian Oceans and Southeast Asia. Among northern feeding aggregations, the Ginoza (26.5°N, 128.0°E) aggregation was also sourced from the Western Pacific Ocean, but the Nomaike (31.4°N, 130.1°E), Muroto (33.2°N, 134.2°E), and Kanto (35.6°N, 140.5°E) aggregations were contributed mostly by the closer Ogasawara rookeries. The reduced contribution from tropical Pacific rookeries to northern feeding aggregations and the significant correlation between genetic differentiation and geographical distance matrices of feeding aggregations indicated that most hatchlings from these regions transported by the Kuroshio Current settle in upstream feeding grounds along the Japanese archipelago, implying that current flow influences the composition of feeding aggregations. Differences in the composition of relatively close neritic feeding aggregations have important conservation implications, for which both regional and multinational conservation strategies are needed.     

Control of Mercury Emissions from a Municipal Solid Waste Incinerator in Japan

Abstract

The control of Hg emissions from a municipal solid waste incinerator (MSWI) is very important, because more than 78% of municipal solid waste (MSW) is incinerated. The Hg content of coal used in utility boilers is relatively low in Japan. In this study, recent trends in the Hg content of MSW in Japan and activated carbon (AC) injection as a control technology of Hg emission from an MSWI are discussed. The effect of AC injection on Hg removal from flue gas in an MSWI was investigated by pilot-scale experiments using a bag filter (BF). The injection of AC increases the Hg reduction ratio by 20–30% compared with cases without AC injection. The Hg reduction ratio increases as the flue gas temperature decreases. The Hg reduction ratio is closely related to the inlet Hg concentration and was expressed with a Langmuir-type adsorption isotherm.     

Demonstration study of high temperature melting for asbestos-containing waste (ACW)

The service life of many buildings and houses built using asbestos-containing materials is coming to an end and their demolition will lead to a great deal of asbestos-containing waste (ACW). Conventionally, the disposal of such waste is conducted by isolation under controlled landfill procedures; however problems with this method exist, such as the risk at the time of re-utilization of landfill sites and the depletion of lands to be reclaimed. Melting treatment is a promising technology that could be used to solve these problems; a thermal process involving temperatures exceeding the melting points of asbestos, it transforms them into non-hazardous minerals. This technology may be applicable not only for friable ACW but also for nonfriable ACW. We performed a demonstration test of melting treatment of nonfriable ACW using a gasification and melting furnace of the shaft furnace type, which is a typical method for high temperature melting. Detailed observation using transmission electron microscopy as well as general analyses verified that the same level of asbestos remained in the slag obtained by high temperature melting as that of the background soil. In addition, the asbestos concentration in the exhaust gas and the dust from the facility were at sufficiently low levels, and it was thus verified that the asbestos concentration in the atmosphere in the vicinity of the facility during the melting treatment was comparable to that of Japan’s background level reported by the Ministry of the Environment in 2007.     

Nitrate facilitates cadmium uptake, transport and accumulation in the hyperaccumulator Sedum plumbizincicola

The aims of this study are to investigate whether and how the nitrogen form (nitrate (NO₃ ^–) versus ammonium (NH₄ ⁺)) influences cadmium (Cd) uptake and translocation and subsequent Cd phytoextraction by the hyperaccumulator species Sedum plumbizincicola. Plants were grown hydroponically with N supplied as either NO₃ ^– or NH₄ ⁺. Short-term (36 h) Cd uptake and translocation were determined innovatively and quantitatively using a positron-emitting ¹⁰⁷Cd tracer and positron-emitting tracer imaging system. The results show that the rates of Cd uptake by roots and transport to the shoots in the NO₃ ^– treatment were more rapid than in the NH₄ ⁺ treatment. After uptake for 36 h, 5.6 (0.056 μM) and 29.0 % (0.290 μM) of total Cd in the solution was non-absorbable in the NO₃ ^– and NH₄ ⁺ treatments, respectively. The local velocity of Cd transport was approximately 1.5-fold higher in roots (3.30 cm h^?1) and 3.7-fold higher in shoots (10.10 cm h^?1) of NO₃ ^–- than NH₄ ⁺-fed plants. Autoradiographic analysis of ¹⁰⁹Cd reveals that NO₃ ^– nutrition enhanced Cd transportation from the main stem to branches and young leaves. Moreover, NO₃ ^– treatment increased Cd, Ca and K concentrations but inhibited Fe and P in the xylem sap. In a 21-day hydroponic culture, shoot biomass and Cd concentration were 1.51 and 2.63 times higher in NO₃ ^–- than in NH₄ ⁺-fed plants. We conclude that compared with NH₄ ⁺, NO₃ ^– promoted the major steps in the transport route followed by Cd from solution to shoots in S. plumbizincicola, namely its uptake by roots, xylem loading, root-to-shoot translocation in the xylem and uploading to the leaves. S. plumbizincicola prefers NO₃ ^– nutrition to NH₄ ⁺ for Cd phytoextraction.     

Online measurements of low-volatile organic chlorine for dioxin monitoring at municipal waste incinerators

In this study, an automatic sampling device and an analysis device have been developed for the measurement of low-volatile organic chlorine (LVOCl) in flue gas. The concentrations of dioxins (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls) have been estimated by online measurements of LVOCl at a municipal solid waste incinerator (MSWI) using these devices. The LVOCl concentration at the outlet of the selective catalyst reactor (SCR) of the MSWI increased momentarily up to 95 μg Cl m⁻³ during the startup period of the MSWI; subsequently, it gradually decreased to less than 1.0 μg Cl m⁻³ after 50 h from the start of waste feeding. The concentration of toxic equivalent quantity (TEQ)-Dioxins at the SCR outlet had a linear positive relationship with the LVOCl concentrations. Moreover, the level of TEQ-Dioxins concentration can be estimated by using this relationship with LVOCl. From our results, since the LVOCl concentrations in a flue gas can thus be automatically analyzed every hour by online measurements, the operators of an MSWI would be able to monitor approximate TEQ-Dioxin emissions on a daily basis.     

Influence of oxygen flow rate and compost addition on reduction of organic matter in aerated waste layer containing mainly incineration residue

Landfilling municipal solid waste incineration (MSWI) residue alkalizes the waste layer, causing a subsequent decrease in microbial activity and a delay in the decomposition of organic matter. In this study, efficiencies of neutralization of the leachate and organic matter decomposition in the waste layer in a column filled with MSWI residue using aeration and compost addition were evaluated.Total organic carbon (TOC) reduction in the waste layer is large at high oxygen flow rate (OFR). To effectively accelerate TOC reduction in the waste layer to which compost was added, a high OFR exceeding that by natural ventilation was required. At day 65, the pH of the leachate when OFR was above 102mol-O2/(day·m3) was lower than that when OFR was below 101mol-O2/(day·m3). At the same OFR, the pH of waste sample was lower than that of waste sample with compost. Although leachate neutralization could be affected by compost addition, TOC reduction in the waste layer became rather small. It is possible that humic substances in compost prevent the decomposition of TOC in MSWI residue.