產婦血、臍帶血與胎盤中砷、鎘、錳、汞、鉛濃度相關性與其 可能暴露來源

Abstract

摘要 孕婦與胎兒屬於易感受性族群，孕婦在懷孕期間接觸到有害重金屬暴露時，可能會對胎兒的健康造成不良影響。本研究目的為探討懷孕期間可能會影響產婦血中砷、鎘、錳、汞、鉛等重金屬濃度的環境暴露因素與其可能暴露途徑，並且討論五種重金屬在產婦血、臍帶血與胎盤中濃度之間的相關性。 研究對象為2004 年5 月至2005 年2 月在大臺北地區三種不同層級醫院分娩的產婦與單胞胎新生兒共480 對。以問卷收集懷孕期間暴露資料，並在分娩前收集產婦血、分娩時收集臍帶血與胎盤等檢體，使用感應耦合電漿質譜儀(ICP-MS)分析檢體中的重金屬濃度。 濃度的表示法為除去高濃度極端值後的濃度幾何平均值(幾何標準差)，依重金屬別一一列出，並且說明其相關性，濃度結果如下：砷在產婦血、臍帶血與胎盤中濃度幾何平均值(幾何標準差)分別為4.47 μg/L (1.66)、3.72 μg/L (1.55)與22.91 ng/g (1.62)，三種檢體的砷濃度間均呈現顯著正相關。鎘在產婦血、臍帶血與胎盤中濃度幾何平均值(幾何標準差)分別為1.15 μg/L (2.04)、0.23 μg/L (3.55)與63.10 ng/g (1.48)，產婦血與胎盤間鎘濃度呈顯著正相關。錳在產婦血、臍帶血與胎盤中濃度幾何平均值(幾何標準差)分別為20.89 μg/L (1.62)、46.77 μg/L (1.38)與549.54 ng/g (1.23)，產婦血與臍帶血、臍帶血與胎盤間錳濃度呈顯著正相關。汞在產婦血、臍帶血與胎盤中濃度幾何平均值(幾何標準差)分別為5.25 μg/L (2.69)、11.48 μg/L (1.86)與213.80 ng/g (1.62)，產婦血、臍帶血與胎盤間汞濃度均呈現顯著正相關。鉛在產婦血、臍帶血與胎盤中濃度幾何平均值(幾何標準差)分別為14.13 μg/L (2.24)、11.48 μg/L (2.00)與66.07 ng/g (1.70)，不同檢體之間的鉛濃度均呈現顯著正相關。 由於禁止使用含鉛汽油，使臺灣的臍帶血中鉛濃度逐漸下降，從2002 至2004年臍帶血中鉛濃度約下降了10 μg/L。產婦血與臍帶血中汞濃度雖然也有逐漸下降趨勢，但是與其他歐美國家研究的濃度值相比仍然偏高。 使用逐步複迴歸模式尋找可能影響產婦血中砷、鎘、錳、汞、鉛濃度高低的暴露因子，結果顯示：收案地區為影響產婦血砷、汞濃度的主要因素。產婦血錳、鉛濃度亦因收案地區不同產生差異。臍帶血中砷、錳、汞、鉛與胎盤中砷、鎘、汞濃度主要受產婦血中濃度所影響。而臍帶血鎘、胎盤錳、鉛濃度高低則主要受到收案地區不同而產生差異。臍帶血、胎盤中鉛濃度受產婦血中濃度與收案地區所影響。 臍帶血鉛濃度值逐漸趨近於先進國家，但是產婦血與臍帶血汞濃度與其他研究地區相比濃度仍然偏高，未來可針對我國懷孕婦女進行懷孕期間的追蹤研究，探尋懷孕期間與汞相關的所有暴露來源，藉此找出我國產婦血與臍帶血中汞濃度偏高的原因。並且為了減少不同收案地區之間人口分佈情形差異對產婦血、臍帶血與胎盤中濃度可能造成的影響，研究對象的收集可以盡量選擇在同樣地區相同層級的醫療院所。

Abstract Pregnant women and fetuses are susceptible to environmental hazards. If women are exposed to heavy metals during pregnancy, their fetuses’ growth development could be adversely affected. Therefore, the aims of the present study were to find the relationship of arsenic, cadmium, manganese, mercury, and lead concentrations among maternal blood, cord blood and placenta, and to explore the potential environmental exposure sources of these five metals. Study subjects included 480 mother and infant pairs collected from three different level hospitals in Taipei area. Questionnaires were administered to get study subjects’ environmental exposure history before and during pregnancy. Biological samples, including maternal blood, cord blood, and placenta, were collected at delivery. Then ICP-MS was applied to analyze arsenic, cadmium, manganese, mercury and lead contents in maternal blood, cord blood, and placenta samples. Metal concentrations in maternal blood, cord blood, and placenta samples were as follows (GM (GSD)): 4.47 μg/L (1.66), 3.72 μg/L (1.55), 22.91 ng/g (1.62) for arsenic, 1.15 μg/L (2.04), 0.23 μg/L (3.55), 63.10 ng/g (1.48) for cadmium, 20.89 μg/L (1.62), 46.77 μg/L (1.38), 549.54 ng/g (1.23) for manganese, 5.25 μg/L (2.69), 11.48 μg/L (1.86), 213.80 ng/g (1.62) for mercury, and 14.13 μg/L (2.24), 11.48 μg/L (2.00), 66.07 ng/g (1.70) for lead, respectively. The correlations among the concentrations of the study metals were examined by Pearson’s correlation. It appeared that arsenic and lead concentrations, respectively, in maternal blood, cord blood, and placenta were significantly and positively correlated. Manganese and mercury concentrations, respectively, in cord blood and placenta were also significantly positively correlated, as well as the mercury concentrations in maternal blood and cord blood. A significant correlation of cadmium concentration was only shown between maternal blood and placenta samples. Because it was prohibited to use leaded gasoline, cord blood lead concentration was continuously decreasing. From 2002 to 2004, cord blood lead concentration was decreased by about 10 μg/L. Although maternal and cord blood mercury concentrations also decreased by 50% during the past years, they were still significantly higher than those of western countries. Multiple stepwise regression models were used to explore the factors affecting the maternal blood, cord blood and placental arsenic, cadmium, manganese, mercury, and lead concentrations. Results showed that study area was the major factor of maternal blood arsenic and mercury concentrations, and also affected maternal blood manganese and lead and cord blood cadmium and placental manganese and lead concentrations. Cord blood arsenic, manganese, mercury and lead and placental arsenic, cadmium and mercury concentrations were affected by those concentrations of maternal blood. In cord blood and placental lead concentrations, maternal blood lead concentration and study area had about the same influence of cord blood and placental lead concentrations. Cord blood lead concentration was getting close to the developed countries. However, mercury concentrations in maternal and cord blood were still high. To find out the exposure mechanism, a follow-up study may be needed to investigate the possible mercury exposure sources for the pregnant women in the future.