著者

鈴木 祥広 西山 正晃 糠澤 桂 石井 聡

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.41, no.2, pp.19-26, 2018 (Released:2018-03-10)

参考文献数

20

被引用文献数

2

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水環境におけるふん便指標細菌である大腸菌は, 環境中で再増殖することが知られており, 指標細菌としての妥当性が懸念されている。そこで本研究では, 下水処理水が流入する小河川において, 下水処理水の流入・混合後の流下過程における大腸菌数の変化について調査した。大腸菌のフラックスは, 上流地点と下水処理水の合計量よりも, その下流地点において増大する傾向を示した。また, 下流地点の底質で高密度の大腸菌数が検出された。そこで, パルスフィールド・ゲル電気泳動法によって大腸菌の遺伝子型の類似性を評価したところ, 上流の河川水, 河床付着物, ならびに底質から単離した大腸菌において遺伝子型の一致する株が確認された。以上のことから, 下水処理水の影響を強く受ける小河川では, 大腸菌が河床の付着物や底質に生残・蓄積しており, 再増殖する可能性も否定できないことが示唆された。河川における大腸菌数によるふん便汚染評価の解釈には, 留意する必要がある。

著者

鈴木 祥広 丸山 俊朗 高見 徹 土手 裕

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.19, no.5, pp.388-396, 1996-05-10 (Released:2008-01-22)

参考文献数

25

被引用文献数

5 4

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Monochloramine (NH2Cl) is the strongest toxic substance resulting from chlorinated sewage effluent. To estimate of NH2Cl on the growth of organisms in coastal region, disappearance of NH2Cl in seawater was investigated.Changes concentration of NH2Cl and total oxidant in artificial seawater were determined. The concentration of NH2Cl decreased with time and reached to 20% of the initial concentration after 6 hour at 30°C. On the other hand, 90% of the initial concentration of total oxidant was detected after disappearance of NH2Cl. The rate constant of NH2Cl disappearance was not concerned in the initial concentration at constant temperature. Disappearance of NH2Cl depended on water temperature, and the rate constant followed the Arrhenius equation. The rate constant and half-life value at 20°C for NH2Cl in seawater were 0.031 h-1 and 10 h. These results suggested that the effluent contained NH2Cl would be enough to effect on coastal organism until its disappearance. NH2Cl disappearance depended on salinity. However, NH2Cl in artificial seawater without KBr was stable even in the same condition. It was clear that the disappearance factor of NH2Cl was in existence of Br-. NH2Cl changed to the other oxidant with Br-, therefore, the product which may act on organisms still remained in seawater after disappearance of NH2Cl.

著者

丸山 俊朗 鈴木 祥広 佐藤 大輔 神田 猛 道下 保

出版者

公益社団法人日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.65, no.5, pp.818-825, 1999-09-15

参考文献数

24

被引用文献数

14 15

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閉鎖循環式の泡沫分離・硝化システムと従来の流水式システムでヒラメを飼育し, 閉鎖循環式養殖の可能性を検討した。本閉鎖循環式システムは, 飼育水槽, 空気自吸式エアーレーターを設置した気液接触・泡沫分離槽, 硝化・固液分離槽, およびpH・水温調整槽からなる。ヒラメ幼魚200尾を収容(初期収容率2.8%)し, 90日間の飼育実験(実験終了時収容率5.0%)を行った。本閉鎖循環式システムと流水式システムを比較すると, 生残率はそれぞれ93.5%と98%であり, また, 飼料効率は, それぞれ117%と110%であった。本閉鎖循環式システムによって, 飼育水をほぼ完全に排水することなしに, 高密度飼育することができた。

著者

高見 徹 丸山 俊朗 鈴木 祥広 三浦 昭雄

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.22, no.1, pp.29-34, 1999-01-10

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In the short-term bioassay using Porphyra yezoensis conchospores, it is basically important to clarify the most appropriate exposure period and end point to evaluate the effects of toxicants on the growth of Porphyra yezoensis conchospores. In this study, short-term bioassays (120 hours) were conducted on copper (Cu) and monochloramine (NH2Cl), which have different chemical characteristics. Three kinds of end points (survival ratio, germination ratio and growth ratio) at exposure periods every 24 hours were compared to define the most appropriate exposure period and end point.The minimum LOECs (lowest-observed-effect concentration) for Cu occurred at exposure period of 96 hours in the three kinds of end points. The 96-h LOECs from the survival ratio, the germination ratio and the growth ratio were 0.046 ± 0.026mg Cu·l-1 (n=5), 0.033 ± 0.027mg Cu·l-1 (n=5), 0.021 ± 0.019mg Cu·l-1 (n=5), respectively. The minimum LOECs for NH2Cl occurred at exposure period of 96 hours in the survival ratio and the growth ratio of 0.093 ± 0.026mg Cl2·l-1 (n=5) and 0.038 ± 0.016mg Cl2·l-1 (n=5), respectively. The minimum LOEC (0.036 ± 0.000mg Cl2·l-1, n=5) for NH2Cl from the germination ratio occurred at the exposure period of 48 hours.Therefore, taking into account of the simplicity of bioassay and its sensitivity to toxicants, it is concluded that the most appropriate exposure period and end point is 96 hours for Cu and 48 hours for NH2Cl judging from the end point of the germination ratio.

著者

高見 徹 丸山 俊朗 鈴木 祥広 三浦 昭雄

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.22, no.1, pp.29-34, 1999-01-10 (Released:2008-01-22)

参考文献数

22

被引用文献数

1

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In the short-term bioassay using Porphyra yezoensis conchospores, it is basically important to clarify the most appropriate exposure period and end point to evaluate the effects of toxicants on the growth of Porphyra yezoensis conchospores. In this study, short-term bioassays (120 hours) were conducted on copper (Cu) and monochloramine (NH2Cl), which have different chemical characteristics. Three kinds of end points (survival ratio, germination ratio and growth ratio) at exposure periods every 24 hours were compared to define the most appropriate exposure period and end point.The minimum LOECs (lowest-observed-effect concentration) for Cu occurred at exposure period of 96 hours in the three kinds of end points. The 96-h LOECs from the survival ratio, the germination ratio and the growth ratio were 0.046 ± 0.026mg Cu·l-1 (n=5), 0.033 ± 0.027mg Cu·l-1 (n=5), 0.021 ± 0.019mg Cu·l-1 (n=5), respectively. The minimum LOECs for NH2Cl occurred at exposure period of 96 hours in the survival ratio and the growth ratio of 0.093 ± 0.026mg Cl2·l-1 (n=5) and 0.038 ± 0.016mg Cl2·l-1 (n=5), respectively. The minimum LOEC (0.036 ± 0.000mg Cl2·l-1, n=5) for NH2Cl from the germination ratio occurred at the exposure period of 48 hours.Therefore, taking into account of the simplicity of bioassay and its sensitivity to toxicants, it is concluded that the most appropriate exposure period and end point is 96 hours for Cu and 48 hours for NH2Cl judging from the end point of the germination ratio.