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81.
Seasonal changes in abundance and development of Calanus pacificus Brodsky were investigated by analyzing samples of different depth strata (0–150 m and 0–1000 m) collected monthly in the Oyashio–Kuroshio Mixed Region. Copepodite stage 5 (C5) emerged from dormancy and matured in early summer. A new generation appeared in July and developed into C5 during summer to autumn. Some of the summer generation arrested development at C5 and persisted below 150 m depth until the following early summer. Although the remainder matured and reproduced in October, a new generation was not observed at the surface during winter. These results suggest that C. pacificus shows two different life-cycle patterns, i.e. one generation annually, with overwintering C5 in deep waters, and two generations annually, with surface development during autumn to winter. The complex life-cycle patterns may be an adaptation to the highly fluctuating surface environment in the Oyashio–Kuroshio Mixed Region.Communicated by T. Ikeda, Hakodate 相似文献
82.
Concentrations of paralytic shellfish poisoning (PSP) toxins in toxic dinoflagellate cells and in marine planktonic copepods were monitored during the bloom of Alexandrium tamarense in Hiroshima Bay, western Japan. Concentration of the toxins retained by copepods was a function of the ambient toxin concentration, i.e. the product of A. tamarense cell density and cellular toxicity. The toxin concentration in copepods increased with the increase of toxicants in the seawater then leveled off, but decreased significantly at higher concentrations. In the field, the maximum toxin concentration was 1.2 pmol ind-1, whereas in the laboratory, the copepod Acartia omorii accumulated a much higher concentration of PSP toxins (24 pmol ind-1). Feeding avoidance against Alexandrium tamarense and a shift to alternative food sources such as diatoms in the field might keep their toxin levels lower than their potentially maximum level. The copepod toxin levels in the field were not so high as to cause an instantaneous lethal effect on their predator fishes but may reach possibly lethal levels after a few days' continuous feeding. Overall toxin retention by copepods after 12 h feeding and 2 h starvation was only 2.5% of total ingested toxins, which suggested that a significant amount of toxins was released into the seawater. Measurements of toxin reduction and gut evacuation suggested that the toxins were removed through both fecal evacuation and metabolism (e.g. excretion, decomposition and transformation). The results, as a whole, imply that copepods can be a link for PSP toxin flux in both pelagic and benthic food webs and can also be a sink for toxins by metabolizing and removing them from the environment.Communicated by T. Ikeda, Hakodate 相似文献
83.
Hirose J Kondo F Nakano T Kobayashi T Hiro N Ando Y Takenaka H Sano K 《Chemosphere》2005,60(8):1018-1024
Wastewater from clinical institutions contains a considerable amount of toxic substances. Among the toxic substances, antineoplastics may induce carcinogenesis, teratogenesis, and the emergence of mutant microorganisms in the environment. Although the incineration or chemical treatments of disposed antineoplastics are recommended, a high energy during incineration and a careful quality control during chemical treatment are required. In this study, we determined the conditions for the electrolytic treatment of an antineoplastic, epirubicin hydrochloride (EH), using two platinum electrodes with a constant current of 100 mA. We analyzed the cytotoxicity, mutagenicity and antibacterial activity of electrolyzed EH and compared them with those of unelectrolyzed EH. Nearly 100% cytotoxicity, mutagenicity and antibacterial activity were eliminated and HPLC did not detect an EH molecule, in the case of electrolysis for 6 h. We also examined the biological cytotoxicities of electrolyzed irinotecan hydrochloride, vincristine sulfate, mitomycin C, paclitaxel, methotrexate and cisplatin, and found that 72.1-99.999% toxicity was eliminated by electrolysis under the same conditions. The biological toxicity of a mixture of these drugs was determined to be decreased by approximately 99% by electrolysis under the same conditions. 相似文献
84.
The present study aimed to resolve the question why marine Synechococcus spp. abundantly occur even at the bottom of the euphotic zone in the Kuroshio are. Photosynthesis under such conditions was examined using simulated blue-green model light (BGL). Results indicated that photosynthesis of marine Synechococcus spp. under BGL is as active enough to support growth of these organisms. Examination of light-harvesting under BGL indicated that active photosynthesis is permitted by an unusually high abundance of phycoerythrin (PE), which is the main light-harvesting pigment for photosystem II (PSII), due to a phycobilisome (PBS) structure which is different from ordinary hemidiscoidals. Although the absorption maximum of PE is located at longer wavelengths than the energy maximum of BGL, PE was found to absorb BGL significantly. Thus, BGL cannot be a typical photosystem I (PSI) light. PSII is also significantly excited by BGL. Carotenoids, which largely absorb BGL, were found to be effective in light-harvesting for PSI. Based on the results obtained, possible reasons why marine Synechococcus spp. commonly occur in warm waters were discussed. Two strains of Synechococcus spp. isolated from the Gulf Stream in 1981 and from Kuroshio, Japan in 1983 were used in the present study. 相似文献
85.
Haruhisa Fukada Noriyuki Takahashi Noriko Hosomi Toshiro Masumoto 《Journal of Material Cycles and Waste Management》2016,18(2):231-238
During tuna processing for human consumption, the fish are initially boiled in water, creating ~7000 tons of wastewater a year in Tosashimizu City, Japan. The wastewater (tuna broth; TB) is rich in free amino acids and peptides; therefore, we investigated two methods of utilizing it beneficially. In experiment 1, crude TB was used as a growth enhancer for two farmed species, juvenile yellowtail (Seriola quinqueradiata) and red sea bream (Pagrus major). Juveniles of both species, fed commercial extruded pellets mixed with 300 mL TB, showed significantly better growth than the unsupplemented control group. In experiment 2, concentrated TB was used as a dietary ingredient for juvenile yellowtail to improve palatability and growth. Dietary preferences and growth were rated as follows: fish meal diet > soy protein concentrate (SPC) + TB diet > SPC + krill meal diet > SPC diet. The beneficial effects of TB as a dietary supplement were evident. Crude TB enhanced juvenile growth at minimal cost. Concentrated TB requires processing, with associated costs; however, it proved to be a valuable fish-feed supplement because of its high palatability and growth-promoting effect. The utilization of TB also contributes to reducing the environmental impact of fish wastewater. 相似文献
86.
Yasunori Ohtsu Ryuzo Yamada Hiroshi Urasaki Tatsuya Misawa Sebastian Popescu Hiroharu Fujita 《Journal of Material Cycles and Waste Management》2010,12(1):25-29
It is necessary to develop a medical waste management system featuring nonburning treatment and safety functions for small
medical institutions. In this article, the development of a waste management system without oxygen injection was achieved
by means of hybrid heating using microwave energy and an electric heater. The shape of the microwave reactor was a rectangular
parallelepiped with a volume of about 0.1 m3. In the experimental setup, microwave energy (2.45 GHz, about 800 W) was injected from the top of the reactor, while the
heater (about 1 kW) was located at the bottom. Heat insulators were set into all the walls of the reactor. The gases generated
in the system were vented through water and activated carbon. Five paper-based diapers with absorbed water were used as the
waste sample. For the evaluation of performance, the reduction rate was defined as the ratio (in percent) of the weight before
and after treatment. The reduction rate as a function of treatment time and the effect of the position of the waste in the
reactor on the reduction rate and the uniformity of treatment were examined for about 3 kg of waste. It was found that the
reduction rate reached as low as 4.2% at 3 h and then 3% after 8 h. The treated profile strongly depended on the position
of the waste in the reactor. In particular, it was clarified that a metal cylindrical enclosure and a needle electrode played
an important role in attaining uniform treatment of the waste. 相似文献
87.
88.
Improvement of permeability of waste sludge by mixing with slag or construction and demolition waste
Hiroshi Asakura Kazuto Endo Masato Yamada Yuzo Inoue Yusaku Ono 《Waste management (New York, N.Y.)》2009,29(6):1877-1884
To determine the allowable ratio of waste sludge required to ensure an aerobic zone in the landfill, we investigated sludge permeability, which involved mixing sludge, the major landfill waste in Japan, at different mixing ratios with other wastes (slag and construction and demolition waste (C&D)). We measured parameters of sample permeability and analyzed parameters that exert a large influence on oxygen penetration depth with a simulation model accounting for both diffusion and convection driven by temperature gradients. We also determined the critical volumetric contents in which gas and/or water permeability change significantly when sludge is mixed with sand or gravel. From the results of the simulations, gas permeability of the layer, the difference between inside and outside temperatures and the oxygen consumption rate exert a large influence on the resulting oxygen penetration depth. The allowable ratio of sludge required to ensure an aerobic zone in the landfill was determined by considering the balance of the above three parameters. By keeping volumetric sludge content to below 25%, air convection and oxygen penetration depth of several meters were achieved in the modeling. 相似文献
89.
An experimental study of the behavior of endocrine-disrupting chemicals (EDCs) in leachate treatment processes (aeration, coagulation and sedimentation, activated carbon adsorption, and advanced oxidation) was conducted and removal efficiencies were evaluated. Among target EDCs, concentrations of BPA (1800 times), DBP (10 times), BBP (40 times), and DEHP (30 times) in leachate are more than ten times higher than those in surface water. BPA, DBP, and BBP can be treated by aeration and DEHP, by advanced oxidation processes. BPA could not be effectively removed by coagulation and sedimentation because most of BPA partitioned in the supernatant. DEHP could hardly be treated by aeration. The removal ratios of DEHP were approximately 50–70% if the generated sediment was removed completely. The removal ratios of DEHP in leachate of 100 m3/d with 100 kg of activated carbon were 50–70%, assuming a complete mixing model. The concentration of DEHP was decreased to below one-tenth in 120 min by advanced oxidation processes. 相似文献
90.
Takayoshi Ueno Toru Shiino Hiroshi Onishi 《Journal of Material Cycles and Waste Management》1999,1(1):25-32
Life cycle assessment (LCA), a quantitative method for evaluating the total environmental impact of a product, from the materials
in its manufacture to its final disposal, is playing an increasingly important role in manufacturing. When the LCA method
is applied to a product containing many kinds of electronic components, there is a need for life cycle inventory (LCI) data
on the components. This paper provides an original calculation of the LCI data for each electronic components industry. These
data show the amount of input energy and emissions into the atmosphere per yen of production yield. It is demonstrated that
the magnitude of the LCI data for each industry is essentially equal to that of the other industries. Furthermore, we conclude
that the LCI data for all electronic components are roughly equivalent, making it possible to calculate the LCI data of any
electronic component by simply multiplying the LCI data for the industry by the price of the component. Furthermore, after
comparing the materials production stages with the component manufacturing stage in the calculation, it became clear that
for several component industries the materials production stage could not be omitted from the calculation.
Received: April 10, 1998 / Accepted: February 8, 1999 相似文献