Katsuhisa Honda

Acceleration of catalytic activity of calcium oxide for biodiesel production

This research was aimed at studying the acceleration of the catalytic activity of calcium oxide (CaO) for developing an effective heterogeneous catalyst for biodiesel production by the transesterification of plant oil with methanol. CaO was activated by pretreatment with methanol and was used for the transesterification reaction. The activation and transesterification reaction conditions were examined. The obtained optimal reaction conditions were 0.1-g CaO, 3.9-g methanol, 15-g rapeseed oil, and 1.5-h activation time at room temperature that provided methyl ester in approximately 90% yield within a reaction time of 3h at 60 degrees C. The activation mechanism was also investigated, and the proposed mechanism is as follows. By pretreatment with methanol, a small amount of CaO gets converted into Ca(OCH(3))(2) that acts as an initiating reagent for the transesterification reaction and produces glycerin as a by-product. Subsequently, a calcium-glycerin complex, formed due to the reaction of CaO with glycerin, functions as the main catalyst and accelerates the transesterification reaction.

Distribution of heavy metals and their age-related changes in the eastern great white egret,Egretta alba modesta, in Korea

Organ and tissue distribution of eight metals (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Hg) and their age-related changes were investigated in the chick and adult eastern great white egret,Egretta alba modesta, collected in Korea. High concentrations of the metals were found in the liver, kidney, feathers, bone, and skin; low values were found in the muscle and brain. A majority of the metal burdens in the chick and adult egrets existed in the muscle, bone, and feathers; about 50% of the Hg was in the feathers. The concentrations of Fe, Mn, Zn, and Cu in organs and tissues of the chicks characteristically changed with age, and their accumulations depended upon the metabolic turnover. In contrast, the concentrations of Pb, Ni, Cd, and Hg increased with age, suggesting that age or exposure time is a dominant factor. However, the younger stage of the downy chicks showed a rapid accumulation plateau of Pb, Ni, Cd, and Hg, and a dilution effect of these metal concentrations by increased body weight with age also was observed. Furthermore, rapid decreases of the body burden of Mn, Cu, Ni, Pb, Cd, and Hg were found in the fledgling birds, indicating that the metals were excreted via the feathers by moulting. These results indicate that consideration of the growth stage of organs and tissues is necessary for understanding the bioaccumulation processes and the toxicological criteria of the metals.

Metal Concentrations in Pelagic Seabirds from the North Pacific Ocean

Concentrations of four essential elements (Fe, Mn, Zn, and Cu) and two toxic metals (Cd and Hg) were measured in selected tissues of 19 pelagic seabird species collected in the North Pacific and neighboring waters. Essential metal concentrations were generally highest in the liver and less variable than toxic metals among species and also within each species. Fe concentrations in the muscle were higher in Alcidae than in the other families, whereas the opposite trend was found for Fe and Mn in the liver. Zn concentrations varied among species, depending on the Cd concentrations. On the other hand, toxic metal concentrations were highest in the liver or kidney and varied widely among species, greatly depending on differences in the diet among species. Extraordinarily high Hg concentrations were found in Black-footed Albatrosses,Diomedea nigripes, exceeding 300 μg/g wet weight in some, and seemed to be due to constraints on the elimination of Hg. Also, some geographical differences in Cd and Hg concentrations of the seabirds were observed. The concentrations of Cd and Hg reported here, however, seem to be natural rather than due to environmental pollution.

Tissue distribution of heavy metals in Dall's porpoise in the northwestern Pacific

Abstract Tissue distribution of heavy metals (iron, manganese, zinc, copper, lead, nickel, cadmium, and mercury) were investigated in the adult male, female, and foetal Dalls porpoises collected by salmon gill net in the north-western North Pacific. Determination of the metals was carried out by atomic absorption spectrophotometry. The heavy metal concentrations in the adults were generally high in liver, and low in blubber. Some metals showed organ- and metal-specific accumulations: zinc, nickel, and lead exhibited high concentrations in skin and bone; the cadmium concentration was relatively high in pancreas and adrenal and the highest concentration was observed in kidney. Similar tissue distribution patterns of metals were also found in the foetus, but the concentrations of manganese in bone, testis, and copper in liver, were relatively high compared with those in the adults. The concentration of cadmium in the foetus was very low, indicating that transplacental transfer of cadmium is negligible. The majority of the metal burdens in the body was in the muscle, liver and bone, whereas relatively high burden of cadmium was in the kidney. Based on these results, the suitability of tissues of a porpoise for ecological and physiological comparisons is discussed.

Seasonal changes in mercury accumulation in the black-eared kite, Milvus migrans lineatus

Abstract Seasonal changes of mercury accumulation in organs and tissues of the black-eared kite were investigated between the pre- and post-moult (April–November). The mercury concentration was high in the feathers, kidney and liver, and low in the skin and bone. About 70% of the mercury burden in the whole body was in the feathers. While the concentration of mercury decreased in most of the tissues during moulting (June–September), it remained constant in feathers throughout. This indicates that moulting is a major excretory pathway for mercury and the age-dependent accumulation of mercury is virtually absent in this species. The question of which kite feathers should be selected as indicators of mercury pollution in birds is discussed.

Distribution of cadmium and zinc in tissues and organs, and their age-related changes in striped dolphins, Stenella coeruleoalba.

Cadmium and zinc concentrations were determined in the tissues and organs, including the fetus, of striped dolphins. The kidney showed the highest cadmium concentration and the hepatic cadmium concentration was also relatively high. A similar distribution pattern among soft tissues was also observed with zinc, where its concentration varied less than that of cadmium. A significant positive correlation between zinc and cadmium was found in both the kidney and the liver; the increase of zinc concentration with cadmium was more marked in the liver (Zn:Cd 3∶1 on molar basis) than kidney (Zn:Cd 1∶1). Negligible cadmium concentration in the fetus suggested that cadmium is not transferred to the fetus via the placenta from the mother. Organ-specific age trends of cadmium and zinc concentrations were presented in detail for muscle, liver, kidney, pancreas, brain, and blood. Both metals showed rapid change during the periods of the fetus and weaning.

Heavy metal accumulations and their recent changes in southern minke whalesBalaenoptera acutorostrata

The concentrations of heavy metals in the livers of southern minke whales,B. acutorostrata, were determined by atomic absorption spectrophotometry, and their accumulation levels and variations were compared to food habit, and biological parameters. The concentration levels and bioconcentration factors of metals in the minke whale were relatively high for Fe and Cd and low for Hg, when compared to seals and small-toothed cetaceans from different waters. For most of the metals examined, the concentrations were log-normally distributed. The concentrations of Fe, Cd, and Hg were positively correlated with age, but a correlation was not observed for the other metals. While the hepatic Fe concentration linearly increased with age, the concentrations of Cd and Hg increased up to the age of about 20 years and thereafter decreased year by year. Such unusual age trends of Cd and Hg are considered to be due to recent changes of the amount of food intake by the minke whale, as a result of structural disturbances in the Antarctic marine ecosystem due to commercial whaling. Also, the hepatic concentrations of metals varied between sexes, and with reproductive status of the matured female; the concentration of Fe was lower in the females than the males, and Fe, Pb, Ni, and Co concentrations in the matured females decreased with progress of gestation.

Tissue distribution of heavy metals in Weddell seals (Leptonychotes weddellii)

Abstract Tissue distributions of heavy metals were investigated in the Weddell seal collected around Syowa Station, Antarctica. Generally, the metal concentrations were high in liver and kidney and low in brain, blubber and skin. Fe in blood and spleen, Zn in bone, and Mn and Cd in pancreas and gastrointestinal organs were also relatively high. Wide variations of the metal concentrations in different bones were also observed. The concentrations of Fe and Cd were positively correlated with moisture content of the bones, while those of Mn and Zn increased with increase of Ca content in the bone. Majority of the metal burden in the body existed in muscle and liver. A relatively high burden of Cd was in the kidney. Based upon these results, the suitability of the tissues of a seal for ecological and toxicological comparisons is discussed.

Removal of dioxins and dioxin-like PCBs from fish oil by countercurrent supercritical CO2 extraction and activated carbon treatment.

It has been known that fish oils are prone to contamination by polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs). In this study, the removal of contaminants from fish oil by countercurrent supercritical CO(2) extraction (CC-SCE) and activated carbon treatment was investigated. Fish oil was treated by CC-SCE at 70 degrees C and 30MPa and with a CO(2)/oil ratio of 72; this resulted in a 93% reduction in the sum of PCDDs, PCDFs and DL-PCBs concentration level by and 85% reduction in toxic equivalency (TEQ). CC-SCE uses 40% less CO(2) and yields 30% more refined oil than semi-batch-type processes. Subsequent treatment by activated carbon reduced the concentration level by 94% and TEQ by 93%. CC-SCE is effective for the removal of DL-PCBs, whereas activated carbon treatment is effective for the removal of PCDD/Fs. These results reveal that the combination of CC-SCE and activated carbon treatment is applicable to the removal of PCDD/Fs and DL-PCBs from fish oil.

Distribution and residue level of mercury, cadmium and lead in Korean birds

In Korea, some bird species have experienced a reduction in numbers since 1960s. This may be due to the destruction of habitats by industrialization, direct or indirect disturbance by people, and increase in the use of toxic contaminants such as organochlorine compounds and heavy metals. In particular, construction of heavy metals. In particular, construction of heavy industrial complexes during the last decade accelerated changes in the environmental quality, which might have influenced the wildlife populations in various ways. However, data on residue levels of contaminants such as organochlorine compounds and toxic metals in Korean birds are very scarce. The present investigation, which examines the tissue distribution of toxic metals (Hg, Cd and Pb) in 16 bird species in Korea, and the residue levels in relation to the feeding habits and habitats, was done in an attempt to learn the general levels of metal pollution in Korean birds.