ザンビア鉱床地域の慢性鉛曝露による毒性影響の解明と授乳期のキレート治療の開発評価

• Project/Area Number: 17J05756
• Research Category: Grant-in-Aid for JSPS Fellows
• Allocation Type: Single-year Grants
• Section: 国内
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Hokkaido University
• Principal Investigator: 豊巻 治也 北海道大学, 獣医学研究科, 特別研究員(DC1)
• Project Period (FY): 2017-04-26 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥3,100,000 (Direct Cost: ¥3,100,000); Fiscal Year 2019: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2018: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2017: ¥1,100,000 (Direct Cost: ¥1,100,000)
• Keywords: 鉛 / アフリカ / ザンビア / 環境汚染 / 母子 / 重金属 / 発展途上国 / 行動モニタリング

Outline of Annual Research Achievements

採用第1年度に調査地域のヒトの母子から採取した試料の誘導結合プラズマ質量分析法（ICP-MS）を用いた鉛濃度の解析では、WHOが推奨する母乳の許容域（2-5μg/dL）を超過する鉛濃度を確認した。また、鉛安定同位体比解析の測定をマルチコレクター型ICP-MSを用いて行ったが、母子の血液と母乳に比べ、乳幼児の糞便が調査地域の土壌に最も近い鉛安定同位体比を示した。このことから母乳は乳幼児の鉛曝露源の1つではあるものの、主な曝露源は土壌など環境中の鉛で有ることが示唆された。

採用第1年度に行ったKabwe市全域を対象とした疫学調査の試料のICP-MSを用いた鉛濃度の測定と、血漿を用いた生化学検査を行った。生化学検査では、25－50％の試料で、肝臓や腎臓に関わる項目の上昇が見られた。また、鉛が特異的に結合し、活性が低減することが知られているアミノレブリン酸脱水素酵素（ALAD）の活性と血中鉛濃度に有意な負の相関があることがわかった。これらの結果から、調査地域の人々は鉛曝露により重篤ではないものの、健康被害が起きている可能性が示唆された。

調査地域内のヒトや動物が高濃度の鉛曝露に対して、何らかの生体防御機構を有し、鉛の毒性を低減していることが示唆された。鉛の毒性影響を考える上で、生体中の鉛の存在形態や組成は重要であるが、知見は少ない。本年度は生体内の鉛の存在形態を解明するべく、調査地域内でサンプリングされたラット試料を用いて、X線吸収微細構造（XAFS）解析を行った。腎臓や肝臓、骨といった各種臓器の測定を行ったが、臓器ごとに異なる鉛の化学形態であることが示唆された。鉛が高濃度に蓄積しやすく、毒性が発現しやすい腎臓や、長期間に渡って鉛が蓄積することが知られる骨で、それぞれ鉛の化学形態が異なることは鉛の毒性を解明して行く上で重要な手がかりであると言える。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] University of Zambia(ザンビア)
• [Int'l Joint Research] University of Zambia(ザンビア)
• [Int'l Joint Research] University of Zambia(Zambia)
• [Journal Article] Factors associated with lead (Pb) exposure on dogs around a Pb mining area, Kabwe, Zambia (2020)
  • Author(s): Toyomaki Haruya、Yabe John、Nakayama Shouta M.M.、Yohannes Yared B.、Muzandu Kaampwe、Liazambi Allan、Ikenaka Yoshinori、Kuritani Takeshi、Nakagawa Mitsuhiro、Ishizuka Mayumi
  • Journal Title: Chemosphere Volume: 247 Pages: 125884-125884
  • DOI: 10.1016/j.chemosphere.2020.125884
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Current trends of blood lead levels, distribution patterns and exposure variations among household members in Kabwe, Zambia (2020)
  • Author(s): Yabe John、Nakayama Shouta MM.、Nakata Hokuto、Toyomaki Haruya、Yohannes Yared B.、Muzandu Kaampwe、Kataba Andrew、Zyambo Golden、Hiwatari Masato、Narita Daiju、Yamada Daichi、Hangoma Peter、Munyinda Nosiku Sipilanyambe、Mufune Tiza、Ikenaka Yoshinori、Choongo Kennedy、Ishizuka Mayumi
  • Journal Title: Chemosphere Volume: 243 Pages: 125412-125412
  • DOI: 10.1016/j.chemosphere.2019.125412
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Multidisciplinary field research in Kabwe, Zambia, towards better understanding of lead contamination of the city - A short report from a field survey (2017)
  • Author(s): Uchida Yoshitaka、Banda Kawawa、Nyambe Imasiku、Hamamoto Toru、Yoshii Yui、Munthali Kabenuka、Mwansa Mukuka、Mukuka Moses、Mutale Mubanga、Yabe John、Toyomaki Haruya、Beyene Yohannes Yared、Nakayama Shouta M. M.、Naruse Nobuyasu、Ishizuka Mayumi、Takahashi Yukihiro
  • Journal Title: BioRxiv Volume: -
  • DOI: 10.1101/096164
  • Open Access / Int'l Joint Research
• [Presentation] Relationship of lead (Pb) exposure between infants and mothers around Pb mining area in Kabwe (2020)
  • Author(s): Toyomaki H, Yabe J, Nakayama, SMM, Yohannes YB, Muzandu K, Ikenaka Y, Nakata H, Choongo K, Kuritani T, Nakagawa M and Ishizuka M
  • Organizer: International Symposium on Chemical Hazard in Wildlife
  • Int'l Joint Research
• [Presentation] Determination of Lead (Pb) exposure on infants living around Pb mining area in Kabwe, Zambia (2019)
  • Author(s): Toyomaki H, Yabe J, Nakayama, SMM, Yohannes YB, Muzandu K, Mizukawa H, Ikenaka Y, Nakata H, Kuritani T, Nakagawa M and Ishizuka M
  • Organizer: The 15th International Congress of Toxicology
  • Int'l Joint Research
• [Presentation] Blood Lead Levels in mothers and infants around Pb mining area in Kabwe, Zambia (2019)
  • Author(s): Haruya Toyomaki, John Yabe, Shouta M.M. Nakayama, Yared B. Yohannes, Kaampwe Muzandu, Hazuki Mizukawa, Yoshinori Ikenaka, Hokuto Nakata, Kennedy Choongo and Mayumi Ishizuka
  • Organizer: International CHEMICAL HAZARD Symposium 2019
  • Int'l Joint Research
• [Presentation] GPS装置を用いた鉛鉱床地域のイヌの行動のモニタリングと鉛曝露の関係性 (2018)
  • Author(s): 豊巻 治也、Yabe John、中山 翔太、Beyene Yared、水川 葉月、池中 良徳、中田 北斗、石塚 真由美
  • Organizer: 第27回環境化学討論会
• [Presentation] XAFSを用いたザンビア鉛汚染地域の生物及び環境試料における鉛の化学形態の解明 (2018)
  • Author(s): 豊巻治也、中山 翔太、中田 北斗、藤森 崇、塩田 憲司、Yabe John、Muzandu Kaampwe、 Beyene Yared、池中 良徳、水川 葉月、石塚 真由美
  • Organizer: 第21回XAFS討論会
• [Presentation] Does dog’s behavior affect the blood lead levels in domestic dogs around lead mining area, Kabwe, Zambia? (2018)
  • Author(s): Haruya Toyomaki, John Yabe, Shouta M.M. Nakayama, Yared Beyene Yohannes, Kaampwe Muzandu, Hazuki Mizukawa, Yoshinori Ikenaka, Hokuto Nakata and Mayumi Ishizuka
  • Organizer: The 6th Sapporo Summer Symposium for One Health (6th SaSSOH)
  • Int'l Joint Research
• [Presentation] Monitoring of blood lead levels in dogs from lead pollution area, Kabwe, Zambia (2018)
  • Author(s): Haruya Toyomaki, Shouta M.M. Nakayama, John Yabe, Yared B. Yohannes, Kaampwe Muzandu, Hazuki Mizukawa, Yoshinori Ikenaka and Mayumi Ishizuka
  • Organizer: 2nd Chemical Hazard Symposium
• [Presentation] The relationship between lead exposure on dogs and their behavior around Pb mining area, Kabwe, Zambia (2018)
  • Author(s): Haruya Toyomaki, John Yabe, Shouta M.M. Nakayama, Yared B. Yohannes, Kaampwe Muzandu, Hazuki Mizukawa, Yoshinori Ikenaka, Hokuto Nakata, Russell Dowling, Jack Caravanos and Mayumi Ishizuka
  • Organizer: SETAC Europe 28th Annual Meeting
  • Int'l Joint Research
• [Presentation] Relationship between blood lead levels in infants and mothers around lead mining area (2018)
  • Author(s): Haruya Toyomaki, John Yabe, Kaampwe Muzandu, Shouta M.M. Nakayama, Yared Beyene Yohannes, Hazuki Mizukawa, Yoshinori Ikenaka, Hokuto Nakata, Takeshi Kuritani, Mitsuhiro Nakagawa and Mayumi Ishizuka
  • Organizer: 2nd International KAMPAI Symposium & JST Mid-term Evaluation Meeting
  • Int'l Joint Research
• [Presentation] Monitoring of Dog’s Behavior using GPS and their blood lead levels (2018)
  • Author(s): Haruya Toyomaki, John Yabe, Shouta M.M. Nakayama, Yared Beyene Yohannes, Kaampwe Muzandu, Hazuki Mizukawa, Yoshinori Ikenaka, Hokuto Nakata and Mayumi Ishizuka
  • Organizer: 2nd International KAMPAI Symposium & JST Mid-term Evaluation Meeting
  • Int'l Joint Research
• [Presentation] Lead levels in Eggs in Kabwe, Zambia: Implication of human exposure (2018)
  • Author(s): Toyomaki H, Yabe J, Nakayama, SMM, Yohannes YB, Muzandu K, Mizukawa H, Ikenaka Y, Nakata H, Kuritani T, Nakagawa M and Ishizuka M
  • Organizer: SOT 57th Annual Meeting And ToxExpo
  • Int'l Joint Research
• [Presentation] Lead exposure on human samples in African countries and lead pollution in Kabwe, Zambia (2017)
  • Author(s): Toyomaki H, Yabe J, Nakayama SMM, Yohannes YB, Muzandu K, Mizukawa H, Ikenaka Y and Mayumi Ishizuka
  • Organizer: 5th Sapporo Summer Seminar for One Health (SaSSOH)
  • Int'l Joint Research
• [Presentation] The relationship of Blood Lead Levels between mothers and infants in Kabwe, Zambia (2017)
  • Author(s): Toyomaki H, Yabe J, Nakayama SMM, Yohannes YB, Muzandu K, Mizukawa H, Ikenaka Y, Nakata H, Russell Dowling, Jack Caravanos and Mayumi Ishizuka
  • Organizer: 9th International Toxicology Symposium
  • Int'l Joint Research
• [Presentation] Extent of lead exposure in mothers and infants living around a“closed”lead mining area, Kabwe, Zambia (2017)
  • Author(s): Toyomaki H, Yabe J, Nakayama, SMM, Yohannes YB, Muzandu K, Mizukawa H, Ikenaka Y, Nakata H, Dowling R, Caravanos J and Ishizuka M
  • Organizer: 1st International KAMPAI Symposium on Sustainable Management of Resources and Environment in the 21st Century in Japan
  • Int'l Joint Research
• [Presentation] Blood Lead Levels in chickens and dogs around lead mining area, Kabwe, Zambia (2017)
  • Author(s): Toyomaki H, Nakayama SM, Yohannes YB, Yabe J, Muzandu K, Mizukawa H, Ikenaka Y and Ishizuka M
  • Organizer: 第26回環境化学討論会
• [Remarks] KAMPAI Project
  • URL: http://satreps-kampai.vetmed.hokudai.ac.jp/