| Project/Area Number |
16K00628
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Environmental risk control and evaluation
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| Research Institution | Public Works Research Institute |
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Principal Investigator |
Kitamura Tomokazu 国立研究開発法人土木研究所, 土木研究所(つくば中央研究所), その他 (30355797)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | アフリカツメガエル / 下水処理水 / 変態 / 生殖腺組織 / 生殖腺 / 両生類 |
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| Outline of Final Research Achievements |
To clarify the effect of treated sewage on tadpole metamorphosis, tadpoles from the genus Xenopus were exposed to treated sewage and chlorinated treated sewage until the tadpoles metamorphosed into frogs and were grown. The chlorine exposure treatments used for the chlorinated treated sewage were: 0.07, 0.04, 0.03, and 0.02 mg/L total residual chlorine. The effects on the metamorphosis and growth of the tadpoles were investigated based on observation of the phenotype, the thyroid during the metamorphosis stage, and the gonad organization of grown frogs.
The number of deaths during the tadpole stage increased slightly at a total residual chlorine concentration of 0.07 mg/L. However, all the tadpoles that survived metamorphosed into frogs. Prevention or delay of metamorphosis were not observed in any of the treatments. In addition, abnormalities were not observed in the thyroid gland organization of the tadpoles or the gonad organization of grown frogs.
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| Academic Significance and Societal Importance of the Research Achievements |
流入下水には、女性、男性、甲状腺ホルモンを攪乱する物質が含まれている場合があり、下水処理が不十分な場合、下水処理水放流先の水生生物の存続に影響が生じる可能性がある。本研究代表者は、これらの生物影響を評価できる生物としてカエルに着目した。カエルは、甲状腺ホルモンの分泌によりオタマジャクシからカエルに変態する。甲状腺ホルモンの分泌に異常が生じると変態に異常が生じる。変態と生殖腺組織の異常を指標とすることで、下水処理水のホルモン攪乱の影響を評価できると考えた。本研究では下水処理水がオタマジャクシの変態、変態したカエルの生殖腺に与える影響を調べ、通常の下水処理水には影響がないことを明らかにした。
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