Monitoring of Low-Level Mercury Exposure in Utero

Research Project

Project/Area Number	06670426
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Public health/Health science
Research Institution	Kagoshima University
Principal Investigator	AKIBA Suminori Kagoshima Univ., Fac of Med., Professor, 医学部, 教授 (50145554)
Co-Investigator(Kenkyū-buntansha)	YAMAMOTO Shinichi Kagoshima Univ., Fac of Med.Assistant Professor, 医学部, 講師 (50230553) ANDO Tetsuo Kagoshima Univ., Fac.of Med., Research Associate, 医学部, 助手 (10107865)
Project Period (FY)	1994 – 1995
Project Status	Completed (Fiscal Year 1995)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1995: ¥1,100,000 (Direct Cost: ¥1,100,000) Fiscal Year 1994: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywords	Maternal blood / Cord blood / RBC mercury levels / Maternofetal correlation / fish consumption / 総水銀濃度 / 胎盤蓄積性 / 胎児移行性 / 臍体血 / 血清脂肪酸
Research Abstract	We collected blood samples from about 300 maternofetal pairs in Kagoshima Prefecture. Informed consent was taken from mothers. Maternal blood samples were taken during 3-4 days after delivery. / Cord blood samples were obtainted from umbilical veins immediately after delivery. Geometric means of total mercury in maternal RBCs were 43.7 and 16.8 ppb for the mothers in Ohshima Municipal Hospital (N=193) and Kagoshima University Medical School Hospital (N=90), respectively. Geomwtric means in cord blood samples were 58.9 and 24.6 ppb in the former and the latter hospitals, respectively. The mercury levels in mothers and their fetuses were about tow-fold higher in Ohshima than in Kagoshima City. The difference may be attributable to the area differences of fish consumption, as report by Suzuki et al.in 1976. The average mercury level in female fetuses (N=90) was 60.8ppb and was higher than that in males (N=103), which was 52.6 ppb. There were nine mothers whose RBC mercury levels exceeded 100 ppb. The highest mercury levels of maternal RBCs was 143.9 ppb. The estimated hair mercury level for this case was 25 ppm. There were 22 fetuses whose cord blood mercury levels exceeded 100 ppb (the highest ; 205.5 ppb). The mercury levels in mothers and fetuses were positively correlated to fish consumption. The rations between cord blood and maternal blood levels were inversely correlated to maternal levles. Of interest was an inverse correlation between cord blood mercury levels and placental weights. Further investigations are necessary to elucidate the mechanisms involved in this observation. Our study, which showed that babies delivered in remote islands in Kagoshima are exposed to relativery high levels of mercury exposure in utero, urges further investigation in this topics.