Effects of low level mercury contamination on health and reproduction in marine high trophic animals

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K00588
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental impact assessment
• Research Institution: Meijo University
• Principal Investigator: Niizuma Yasuaki 名城大学, 農学部, 教授 (00387763)
• Co-Investigator(Kenkyū-buntansha): 大浦 健 名城大学, 農学部, 教授 (60315851)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 水銀 / 低レベル汚染 / 繁殖 / 繁殖行動 / 内分泌器官 / ウミネコ

Outline of Final Research Achievements

Because of bioaccumulation and biomagnification of environmental Hg in marine food web, seabirds being higher trophic levels are exposed a high level of Hg contamination compared to lower ones. However, little is known about the effect of lower level of Hg contamination on seabirds. In this study we investigated the oxidative stress, the accumulation of Hg in endocrine glands and the breeding behavior in black-tailed gulls Larus crassirostris in order to estimate the effect of lower contamination of Hg on their breeding. Their antioxidative activities were significantly decreased with Hg concentration in blood. Adrenal glands accumulated Hg at the highest level among other tissues and the Hg concentration in the glands were not significantly correlated to that in blood. The number of feeding were significantly decreased with Hg concentration in blood. The results suggest that lower level of Hg contamination could have significant effects on their breeding in black-tailed gulls.

Free Research Field

動物生理生態学

Academic Significance and Societal Importance of the Research Achievements

アジア地域から排出される水銀の越境汚染は日本沿岸海域まで拡大している．海洋生態系の高次補食動物である海鳥類は低濃度の水銀汚染にさらされている．ヒトの場合，たとえ低濃度の水銀摂取であっても胎児や乳幼児への危険性が認められている．本研究では，日本列島沿岸に広く繁殖するウミネコをモデル生物とし，低濃度の水銀汚染でも繁殖行動に負の影響があることを野生動物で初めて示した．魚を食べることの多い日本では，野生動物と同様にヒトについても注視する必要があるかもしれない．また，生物多様性の保全の観点からも，高次捕食動物の水銀汚染の動向をモニターする必要があるだろう．