Journal of Japan Society on Water Environment
Online ISSN : 1881-3690
Print ISSN : 0916-8958
ISSN-L : 0916-8958
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Volume 39, Issue 3
Displaying 1-4 of 4 articles from this issue
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Research Paper
  • Individual and Combined Toxicity of Antibacterial Substances to Green Alga Pseudokirchneriella subcapitata
    Satoshi YAGI, Hokuto KAWAKAMI, Takuma FUJIWARA, Nao ISHIKAWA, Ayumi IT ...
    Article type: Research Paper
    2016 Volume 39 Issue 3 Pages 63-70
    Published: 2016
    Released on J-STAGE: May 10, 2016
    DOIhttps://doi.org/10.2965/jswe.39.63
    JOURNAL FREE ACCESS
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    Acute toxicity tests were carried out to obtain EC50 for ten types of antibiotic substances, i.e., cefazolin, oxytetracycline, doxycyclin hyclate, amoxicillin, tylosin, lincomycin HCl, oxolinic acid, sulfamonomethoxin, enrofloxacine, and trimethoprim, for the green alga Pseudokirchneriella subcapitata. Through a comparison of EC50 obtained in this study with that for a variety of species, the relationships between action mechanisms of the antibiotic substances and growth inhibitions of P. subcapitata were discussed. Then, another acute toxicity test was performed to assess the growth inhibition when using the mixtures of enrofloxacine and sulfamonomethoxin or enrofloxacine and lincomycin at certain specific mixing ratios that had been determined to be Toxic Unit (TU) mixing ratios. The results indicated that the toxicities of both mixtures to P. subcapitata were shown to be an additive effect.
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  • Distribution and Behavior of Zinc in Tidal Urban Rivers
    Masanao SHINYA, Takayuki NISHIO
    Article type: Research Paper
    2016 Volume 39 Issue 3 Pages 71-78
    Published: 2016
    Released on J-STAGE: May 10, 2016
    DOIhttps://doi.org/10.2965/jswe.39.71
    JOURNAL FREE ACCESS
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    Zinc concentration, speciation, distribution and behavior in the tidal urban area of the Yodo River basin were determined in order to examine the level of the effect on aquatic life. Dissolved zinc, accounting for 49 to 89% of total zinc, was present at a higher rate in rivers in the Neya River area, discharged into by a large volume of sewage treatment water, while free zinc ions, known as one of the most toxic species in general, were present at a lower rate. The Neya River area was estimated to account for approximately three-fifths of the watershed load of total zinc, and two-thirds of that of dissolved zinc. In the brackish water area of the Aji River, the estimated load has been decreased to 87% for total zinc and 78% for dissolved zinc, because zinc was considered to change from the dissolved form in water to a suspended form owing to iron coprecipitation with rising pH, indicating an accumulation of zinc in the sediment. On the other hand, little elution of zinc from the sediment in the brackish water area was observed.
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  • Removal Properties of Boron Ion Pair in Leachates from Coal Fly Ash
    Kyoko OISHI, Yugo MAEHATA
    Article type: Research Paper
    2016 Volume 39 Issue 3 Pages 79-83
    Published: 2016
    Released on J-STAGE: May 10, 2016
    DOIhttps://doi.org/10.2965/jswe.39.79
    JOURNAL FREE ACCESS
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    Effective boron removal from coal fly ash containing various elements was studied. Dilute HCl is used to leach Al, Ca, and Mg in addition to boron from coal fly ash. The dissolved boron forms borate-ion pair, CaH2BO3+ and B (OH) 4-, under high pH conditions in the presence of Ca. The positive borate-ion pair CaH2BO3+may form coordinative bonds with Al (OH) 4- and finally be removed by coprecipitation. The negative borate-ion pair B (OH) 4- may form a complex with the diol group of polysaccharides. In this study, the effects of pH and the addition of Al on boron removal from the acid leachate of coal fly ash were investigated. The pH of the leachate was adjusted to 12, 11, 10.5 and 10. Then AlCl3aq was added to give Al/B molar ratios of 1, 10 and 50. After CaH2BO3+ was coprecipitated with Al (OH) 4-, the dissolved B (OH) 4- was adsorbed at pH12 using glucomannan semigel. The highest removal ratio of CaH2BO3+ was obtained under the condition of pH10 and Al/B molar ratio of 50, and that of B (OH) 4- at pH12. About 78% of the boron leached from the coal fly ash was finally removed by the combination of coprecipitation and adsorption.
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Survey Paper
  • Fish Fauna of River Kamatani in the Reintroduction Site of Oriental White Stork (Ciconia boyciana) , Hyogo Prefecture
    Moe MIYANISHI, Rinako TOKUDA, Shiro SAGAWA, Yasuo EZAKI, Kazumi HOSOYA
    Article type: Survey Paper
    2016 Volume 39 Issue 3 Pages 85-90
    Published: 2016
    Released on J-STAGE: May 10, 2016
    DOIhttps://doi.org/10.2965/jswe.39.85
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    The fish fauna of River Kamatani, a tributary of River Maruyama drainage system, was surveyed in June and August 2014. Twenty-two fish species/subspecies, belonging to six fish families, were caught at four stations. The oriental white stork favors a foraging habitat with high biodiversity and rich food. Crucian carp, Carassius spp., was identified as a valuable prey for the oriental white stork. The fish community structure differed between the middle and upper reaches of River Kamatani. Biodiversity was higher in the lower reaches than in the upper reaches of the river. To increase the fish population in River Kamatani, it is necessary to maintain the continuity of the river in terms of fish migration.
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