環境微量金屬暴露追蹤監測－－臍帶血中鉛與其他金屬濃度

Abstract

胎兒及孕婦是環境中重金屬汙染物暴露的易感受族群，金屬暴露的危害範圍包括神經與生殖系統、新生兒出生健康狀況、胎兒的成長和發育等。本研究所屬單位過去分別在民國76年、81年、91年與94年持續監測大臺北地區新生兒臍帶血中鉛濃度，本研究再次以同區域範圍進行孕婦及新生兒臍帶血中鉛及其他多種微量重金屬元素濃度分布之調查，並比較過往三十二年間孕婦及新生兒臍帶血中多種微量金屬元素之變動趨勢與影響因素演變。 本研究於2016年11月至2018年6月邀請在臺大醫院隨機選取之孕婦及其新生兒作為研究對象，採集孕婦分娩前之血液樣本，以及分娩時之臍帶血樣本，並使用感應耦合電漿質譜儀(ICP-MS)分析樣本中砷、鎘、鉻、錳、鉛、鋅等微量金屬元素濃度。同時利用問卷收集人口學及暴露資料，以分析社經條件、生活與環境等因素對孕婦血液及臍帶血中鉛及其他受關注金屬濃度之影響。 分析結果顯示，孕婦血液樣本中砷、鎘、鉻、錳、鉛、鋅的濃度分別為4.45±2.52 μg/L、0.63±0.38 μg/L、3.01±4.75 μg/L、29.5±8.0 μg/L、10.9±6.7 μg/L、6,121±1,457 μg/L。而臍帶血中砷、鎘、鉻、錳、鉛、鋅的濃度分別為 4.38±2.05 μg/L、0.36±0.38 μg/L、1.11±1.46 μg/L、66.0±20.0 μg/L、8.1±4.5 μg/L、2,219±473 μg/L。比起往年，孕婦血液及臍帶血中鉛、鎘、鋅濃度皆呈現下降趨勢。孕婦血液及臍帶血中砷濃度(r=0.885, p<0.0001)、錳濃度(r=0.198, p=0.041)、鉛濃度(r=0.58, p<0.0001)及鋅濃度(r=0.218, p=0.0244)均呈現顯著正相關，顯示這四項金屬元素容易穿過胎盤進入胎兒體內。而孕婦血液及臍帶血中鎘及鉻濃度則是沒有顯著的相關。 Multiple logistic regression分析結果顯示，服用鈣片之頻率越高的孕婦比未服用的孕婦容易有較低的血中砷濃度(OR=0.50, p=0.019)。使用銀粉補牙的孕婦比未使用的孕婦容易有較低的鉛濃度(OR=0.36, p=0.037)，其新生兒臍帶血中鉛濃度也較低(OR=0.36, p=0.031)。而於懷孕前抽菸之孕婦比未抽菸的孕婦容易有較高的血中鉛濃度(OR=7.13, p=0.021)。於懷孕期間有使用口紅的孕婦比未使用的孕婦，其新生兒臍帶血中容易有較高的鉻濃度(OR=4.90, p=0.046)。 目前環境金屬危害暴露型態已由過去的急性、高劑量暴露逐漸轉變成長期、低劑量之暴露，如同本研究發現化妝品、健康食品、飲食習慣等因素對微量金屬暴露的影響漸漸浮現。這些金屬暴露程度雖是低濃度範疇，但長期可能造成之健康效應仍值得關注。

Fetus and pregnant women are susceptible to heavy metal exposure, with adverse health concerns on neurological and reproduction system, fetus growth and development, and newborn health status at birth. Following the previous serial studies conducted by this institute to report the cord blood lead levels of newborns in Taipei metropolitan area in 1987, 1992, 2002 and 2005, this study was therefore carried out in the same study area to examine multiple metal concentrations, including lead, in the blood samples of pregnant women and their newborns’ cord blood samples. The aim of this study was to examine the transition trends of lead and other metal concentrations in maternal and cord blood samples in the past 32 years and the relevant affecting factors. Pregnant women visiting National Taiwan University Hospital from November 2016 to June 2018 were randomly invited to participate in this study. Maternal blood samples were collected when the pregnant women were admitted to the hospital for delivery and cord blood samples were collected at delivery. Both the maternal blood samples and the cord blood samples were determined for arsenic, cadmium, chromium, manganese, lead and zinc by inductively coupled plasma mass spectrometry. Information on demographics and environmental exposure factors were obtained through questionnaire administration and used to examine their effects on the distributions of multiple metal levels in the maternal blood samples and the cord blood samples. The mean arsenic, cadmium, chromium, manganese, lead and zinc levels in maternal blood samples were 4.45±2.52 μg/L, 0.63±0.38 μg/L, 3.01±4.75 μg/L, 29.5±8.0 μg/L, 10.9±6.7 μg/L, 6,121±1,457 μg/L, respectively, and those in the cord blood samples were 4.38±2.05 μg/L, 0.36±0.38 μg/L, 1.11±1.46 μg/L, 66.0±20.0 μg/L, 8.1± 4.5μg/L, 2,219±473 μg/L, respectively. The levels of lead, cadmium and zinc in both maternal and cord blood samples continuously declined in the past years. Positive correlations were found between the maternal blood samples and the cord blood samples for arsenic (r=0.885, p<0.0001), manganese (r=0.198, p=0.041), lead (r=0.580, p<0.0001) and zinc concentrations (r=0.218, p=0.0244), implying significant transfer of arsenic, manganese, lead and zinc through placenta to the fetus. Meanwhile, there are no significant correlations present between the maternal blood samples and the cord blood samples for cadmium and chromium concentration. Results of multiple logistic regression analyses showed that intake frequency of calcium supplement was found negatively associated with arsenic level in the maternal blood samples (OR=0.50, p=0.019). Lead level in the maternal blood and cord blood samples were found negatively associated with amalgam fillings (OR=0.36, p=0.037 and OR=0.36, p=0.031, respectively). Maternal smoking habit before pregnancy was found positively associated with lead level in the maternal blood samples (OR=7.13, p=0.021). The habit of using lipstick during pregnancy was found positively associated with chromium level in the cord blood samples (OR=4.90, p=0.046). Nowadays, the pattern of environmental metal exposure has turned into long-term and low level exposure. This study suggested the effects of cosmetics and nutritional supplement consumption, and dietary habits on metal exposure levels were emerging. Although these metal exposures are at relatively low levels, their potential adverse health impacts are still deserved of concern.