Concentration Distributions of Trace Elements and Heavy Metals in Umbilical Cord Blood in Taiwan

金屬元素遍佈於環境中，有些是天然環境中已存在的，但有些是人為所產生的。人類透過各種日常活動暴露到這些環境金屬元素，尤其懷孕婦女與其胎兒更是易感受族群。藉由血液金屬多元素分析作為生物監測之工具，可以較具體地瞭解人體內金屬元素暴露的情形。因此本研究的目的設定為：.藉由分析臍帶血中18種金屬元素濃度，建立台灣臍帶血中金屬濃度之常模值，作為環境汙染暴露監測的基礎背景參考資料。.探討臍帶血中18種金屬元素濃度分布之相關影響因子。研究收樣期間為2004年4月到2005年7月，共收集1526對產婦及其新生兒為研究對象，所有受邀產婦會被告知相關問卷與樣本收集流程，並請其簽署參與計劃同意書。問卷資料在產婦分娩後進行收集，而臍帶血樣本則在分娩時，由護士進行採樣，並儲存於-80℃冰箱保存。總共收集1407個臍帶血樣本，以感應偶合電漿質譜儀進行18種金屬元素的分析，包括鈹(Be)、鉻(Cr)、錳(Mn)、鈷(Co)、鎳(Ni)、銅(Cu)、鋅(Zn)、砷(As)、硒(Se)、鉬(Mo)、鎘(Cd)、銻(Sb)、鉑(Pt)、汞(Hg)、鉈(Tl)、鉛(Pb)、釷(Th)、鈾(U)等共18種元素。帶血金屬濃度分布其特性顯示，臍帶血中濃度最高金屬元素為鋅(Zn)，平均濃度值為2452 ± 1018 μg/L。其次為銅(Cu)、硒(Se)，其平均濃度值分別為534 ± 105 μg/L、204 ± 47 μg/L。再其次為錳(Mn)、汞(Hg)、鉛(Pb)等，平均濃度分別為48.9 ± 15.7、10.8 ± 6.5、13.9 ± 6.0 μg/L。去二十年來，台灣臍帶血中鉛濃度從1987年74.8 μg/L下降至本研究2005年測得的14.5 μg/L。而臍帶血中汞濃度也從1988年28.8 μg/L下降至本研究2005年測得的11.6 μg/L。ANOVA統計分析結果顯示，除了鎳元素，其他17種臍帶血中金屬元素濃度在產婦居住地理區域分組間有顯著差異(p<0.0001)。臍帶血中汞濃度，隨著產婦教育程度與家庭年收入的提高，濃度有升高的現象，而臍帶血中鉛濃度則是呈相反趨勢(p<0.05)。同時，汞濃度在產婦年齡分組間有顯著差異(p<0.05)。逐步複迴歸分析結果顯示，產婦懷孕期間是否吸煙會影響臍帶血中鎘濃度 (β=0.201, p<0.001)。影響臍帶血中鉛濃度的因素則包括產婦年齡(β=0.159, p<0.05)、產婦教育程度(β=－1.050, p<0.001)。臍帶血中汞濃度則受產婦年齡(β=0.193, p<0.001)、產婦教育程度(β=0.996, p<0.001)、食用海水魚量(β=0.260, p<0.01)、食用淡水魚量(β=－0.273, p<0.15)等因素的影響。由本研究得知台灣新生兒的臍帶血中金屬元素暴露常模值，提供後續其他研究作為參考。而台灣臍帶血中鉛、汞濃度已有下降的現象，目前臍帶血中鉛、汞濃度約為10 μg/L等級。如此低濃度暴露是否會帶來相關的新生兒健康危害，仍需持續關切。帶血中金屬元素濃度監測，可作為新生兒受環境中金屬暴露的指標。因此建立國人相關血中金屬多元素監測是必要的，藉長期血液中金屬濃度的變化趨勢與空間分布關係來瞭解人類受環境金屬污染暴露情形。Trace metals are widely distributed in our environment (air, water and soil). People usually expose to trace metals by daily activities.Pregnant women and their neonates are particularly susceptible to them. Biomonitoring of metal elements in blood has become an important tool to characterize the distributions of trace metals in human body.The aim of this study was set to understand the distributions of trace metals in umbilical cord blood in Taiwan and establish the corresponding norm values for further environmental pollution monitoring, and to explore the potential determinants for the metal concentrations in umbilical cord blood.n total, 1526 pairs of delivering women and their neonates were recruited from April 2004 to July 2005. All participants were informed about the content of this research and the statements of consents have been signed before they participated in the study. Questionnaire information was collected from delivering women after delivery.n total, 1407 Cord blood samples were collected at delivery by nurses and stored in EDTA tubes under -80℃ frozen condition until laboratory analysis with inductively coupled plasma mass spectrometry for 18 trace elements, including As, Be, Cd, Cr, Co, Cu, Ga, Hg, Mn, Mo, Ni, Pb, Pt, Sb, Se, Tl, Th, Zn, U.he highest concentration of metal in cord blood was found for zinc with mean of 2452 ± 1018 μg/L, followed by copper and selenium with means of 534 ± 105 μg/L and 204 ± 47 μg/L, respectively, and by manganese, mercury, lead with means of 48.9 ± 15.7、10.8 ± 6.5、13.9 ± 6.0 μg/L, respectively.ver the past two decades, cord blood lead level in Taiwan declined from 74.8 μg/L in 1987 to 14.5 μg/L in 2005. The mercury level in umbilical cord blood also decreased from 28.8 μg/L in 1988 to 11.6 μg/L in 2005.esults of ANOVA indicated there was significant difference among geographical zones for all study metal levels in cord blood expect for Ni (p<0.0001). The concentration of Hg in umbilical cord blood was positively associated with maternal education and family income levels, while that of Pb was negatively (p<0.05). Meanwhile, there was significant difference in cord blood Hg level among age groups of delivering women.n conclusion, the norms of metal levels in cord blood in Taiwan were established, and could be used as references in further. Cord blood lead and mercury levels in Taiwan presented a decreasing trend in th past years. The current cord blood lead and mercury levels is about 10 μg/L. It’s still of concern whether such low level exposure to lead and mercury would lead to potential adverse health effects of neonates.n the future, a longitudinal monitoring for cord blood metals shall be established to monitor the longitudinal and spatial trend of blood metal level to characterize the human exposure to environmental metal pollutants.摘要.................................................................................................................................. Ibstract.......................................................................................................................... III一章 研究背景............................................................................................................ 1二章 研究目的............................................................................................................ 2三章 文獻回顧............................................................................................................ 3.1 砷........................................................................................................................ 3.2 鎘........................................................................................................................ 4.3 汞........................................................................................................................ 5.4 錳........................................................................................................................ 6.5 鉛........................................................................................................................ 6.6 其它必需元素................................................................................................... 7.7 稀有元素使用情形........................................................................................... 8.8 分析技術........................................................................................................... 9.9 生物監測（Biological Monitoring） ............................................................... 9.10 低濃度分布情形............................................................................................. 9.11 胎兒易感受族群........................................................................................... 10.12 各國臍帶血中金屬濃度的研究情形........................................................... 10四章 材料與方法...................................................................................................... 12.1 研究族群......................................................................................................... 12.2 問卷資料收集................................................................................................. 12.3 臍帶血樣本收集............................................................................................. 13.4 臍帶血樣本處理與分析................................................................................. 13.4.1 臍帶血樣本處理.................................................................................. 13.4.2 檢量線樣本配製.................................................................................. 13.4.3 血液樣本分析...................................................................................... 14.5 實驗分析之品質管制..................................................................................... 14.6 統計分析......................................................................................................... 15五章 結果.................................................................................................................. 16六章 討論.................................................................................................................. 24七章 結論與建議...................................................................................................... 35八章 參考文獻.......................................................................................................... 3