International comparative study on Neuropathy of chronic arsenic poisoning due to High to Medium / Low concentration arsenic exposure

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K10052
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 58020:Hygiene and public health-related: including laboratory approach
• Research Institution: University of Miyazaki
• Principal Investigator: Mochizuki Hitoshi 宮崎大学, 医学部, 講師 (50501699)
• Co-Investigator(Kenkyū-buntansha): 菱川 善隆 宮崎大学, 医学部, 教授 (60304276)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 重金属中毒 / ヒ素中毒 / 神経障害

Outline of Final Research Achievements

Regarding sensory impairment, an analysis in Myanmar showed that the group with arsenic concentration in drinking water (ACDW) of 10 ppb or higher had significantly higher subjective symptoms of weakness and persistent numbness and pain. Objective neurological findings showed that the group with ACDW of 50 ppb or higher had a higher rate of pain and vibration sensation impairment. Objective peripheral neuropathy (both small and large diameter fibers) was estimated to occur at around 50 ppb of ACDW. Regarding hearing impairment, even high-concentration exposure in the Toroku area did not leave any sequelae in the long term in adults. Conversely, analysis in Myanmar suggests that even low concentrations may cause hearing impairment in children. When considering arsenic-induced neuropathy, it is necessary to carefully consider the factors of the exposed side, including age.

Free Research Field

脳神経内科

Academic Significance and Societal Importance of the Research Achievements

飲料水ヒ素濃度と感覚障害に関しての末梢神経障害の関連を報告した。今回の研究にて、神経障害の閾値（dose-response関係）を世界で初めて示した。また、安全な飲料水のヒ素濃度はWHOが推奨する 10ppb以下が適切と思われた。ヒ素濃度の安全な閾値は年齢によって異なる可能性を示した。ヒ素による神経障害を検討する際には、曝露されるヒ素の濃度、期間以外に、年齢を含めた曝露される側の要素を十分に考慮する必要がある。