The risk assessment and biological defense mechanism for high methylmercury exposure group eating whale and tuna

• Project/Area Number: 16H02972
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental impact assessment
• Research Institution: National Institute for Minamata Disease
• Principal Investigator: Nakamura Masaaki 国立水俣病総合研究センター, その他部局等, 部長 (50399672)
• Co-Investigator(Kenkyū-buntansha): 郡山 千早 鹿児島大学, 医歯学域医学系, 教授 (30274814) ; 坂本 峰至 国立水俣病総合研究センター, その他部局等, 主任研究員 (60344420) ; 植田 光晴 熊本大学, 医学部附属病院, 講師 (60452885) ; 山元 恵 国立水俣病総合研究センター, その他部局等, 部長 (70344421)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥14,040,000 (Direct Cost: ¥10,800,000、Indirect Cost: ¥3,240,000); Fiscal Year 2018: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2017: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000); Fiscal Year 2016: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
• Keywords: メチル水銀 / 健康影響 / 小児発達 / 生体防御機構 / 健康影響評価

Outline of Final Research Achievements

Since the apparent health effect by clear methylmercury (MeHg) was not seen by adult population in Taiji-cho, we tried detection of serum proteins correlated with blood cell mercury concentration. The three candidate proteins (ApoE, TTR, adiponectin) were obtained as a result of two-dimensional electrophoresis. When relevance between the concentration of blood cell mercury and these proteins was investigated by ELISA, serum TTR concentrations were significant positive associated with blood cell mercury concentrations and serum adiponectin concentrations were negative associated with blood cell mercury concentrations.
Moreover, we conducted influence investigation to the child development by MeHg exposure, and acquired the data of 133 examples. Now, we have been analyzing the association between umbilical cord MeHg concentration (index of prenatal MeHg exposure of an embryo term) or hair mercury concentration (index of postnatal MeHg exposure) and a neuronal development index.

Academic Significance and Societal Importance of the Research Achievements

これまで、公害や農薬による人工的な汚染と通常の魚食とを区別されないまま、魚食を通じたメチル水銀摂取のリスク評価がなされてきた。太地町の調査で通常の魚食摂取による高濃度の水銀曝露による成人の健康影響が見られなかったが、その理由を解明することで、日本人の食生活で重要な位置を占める魚食の安全性に対するクライテリアの確立およびメチル水銀の毒性軽減の手掛かりが得られることが期待される。
また、メチル水銀曝露による小児発達に及ぼす影響は結論がでていないが、今回の小児検診によりメチル水銀曝露が小児発達に及ぼす影響が明らかになることが期待される。

Research Products

• [Presentation] Associations between mercury levels in hair and fish consumption among children in the south area of Wakayama Prefecture, Japan. (2019)
  • Author(s): Yamamoto M, Itatani M, Nakamura M, Koriyama C, Sakamoto M
  • Organizer: 58th Annual Meeting of Society of Toxicology
  • Int'l Joint Research
• [Presentation] Methylmercury exposure and health survey in a whaling town, Japan (2016)
  • Author(s): 中村政明
  • Organizer: International Association for the Scientific Study of Intellectual and Developmental Disabilities（IASSIDD）
  • Place of Presentation: オーストラリア・メルボルン
  • Year and Date: 2016-08-15
  • Int'l Joint Research
• [Remarks] クジラ由来の高濃度メチル水銀の健康リスク評価
  • URL: http://nimd.env.go.jp/kenkyu/docs/h29nenpoh.pdf#page=66
• [Remarks] クジラ由来の高濃度メチル水銀の健康リスク評価
  • URL: http://www.nimd.go.jp/kenkyu/docs/h28nenpoh.pdf#page=60