Concentration Distributions of Trace Metals in Umbilical Cord Blood in Taiwan

1. Concentration Distributions of Trace Metals in Umbilical Cord Blood in Taiwan Chun-Hung Liu , Yaw-Huei Hwang Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University Background Trace metals are widely distributed in our environment (air, water and soil). Some metals are essential for human health, but some are hazardous. Studies in animals show that high arsenic and cadmium exposures during pregnancy can cause illness in babies. There is some evidence that they can affect neonatal development. As we have known, the hazard of mercury and lead are mainly about the nervous system. Selenium is one of the essential trace metals in human and plays important roles in cofactors of some enzymes and antioxidant system. People usually expose to trace metals by human daily activities; particularly pregnant women and neonates are susceptible to them. When they expose to hazard substances or lack essential elements during pregnancy, it would cause temporal or lasting health effect to them. Therefore, it is worth investigating the distributions of trace metals in umbilical cord blood. Objectives 1.To understand the distributions of trace metals in umbilical cord blood in Taiwan. 2.To establish the reference values in umbilical cord blood. Materials and methods Study population In total, 1526 pairs of mothers and their neonates were recruited from two study programs in Taiwan. One was recruited from April 2004 to January 2005, including 335 pairs in one medical center in Taipei, 50 pairs in one local hospital in Sanshia and 101 pairs in two clinics in Shijhuang and Lujou. The other was recruited from May 2004 to July 2005, including 1040 pairs in Shijhuang, Yunlin, Chiayi, Tainan, Kaohsiung and Taitung. All participants were informed about the content of this research and the informed consents were signed before they participated in the study. Data collection Questionnaire was completed by mother after delivery. Basic information, including age, occupation, education level, family income, nationality and so on was obtained by questionnaires. Additionally, gestation information, history of pregnancy, home environment information were collected in this study. Nurses were responsible for the information collection of neonatal growth status. Sampling and Trace elements analysis Nurses were asked to collect biological samples. Cord bloods were collected at birth in EDTA tubes. After that, these blood samples were allocated to different tubes and they were stored under -80℃ frozen condition until laboratory analysis was performed. For the analysis of maternal and umbilical whole bloods, they were diluted ten times with a solution comprising 5 g/L of 25% ammonia, 0.5 g/L Triton X-100 and 0.5 g/L EDTA in double de ionized water. After being filtered, the diluted samples were analyzed by inductively coupled plasma mass spectrometry, 7500C, Agilent Technologies, Inc., Japan. The trace elements determined in this study included As, Ba, Be, Cd, Ce, Co, Cu, Ga, Hg, Mn, Mo, Pb, Pt, Sb, Se, Th, Zn, U. Result Discussion Table1. Concentration distributions of 18 cord blood metal elements (μg/L) 1. sample representativeness 2. Concentration distributions of 18 elements 3. Compared with other study results *Outliers have been discarded if the value is greater than mean plus 3*SD