Cernichiari E, Toribara T Y, Liang L, Marsh D O, Berlin M W, Myers G J, Cox C, Shamlaye C F, Choisy O, Davidson P
Department of Environmental Medicine, University of Rochester School of Medicine, New York 14642, USA.
Neurotoxicology. 1995 Winter;16(4):613-28.
The concentration of total mercury in maternal hair during pregnancy was used as a measure of fetal exposure to methylmercury in a study of a fish-eating population in the Seychelles islands. A segment of scalp hair approximately 10 centimeters in length, that grew during pregnancy, was selected for measurement. Total and inorganic mercury were measured by cold vapor atomic absorption (CVAA) using the Magos reagents (Magos, 1971). For comparative purposes, total mercury was measured by X-ray Fluorescent Spectrometry (XRF) and methylmercury by gas chromatography/atomic fluorescence detection (GC/AFD) in a subset of hair samples. A limited number of fish samples were also analyzed. Extensive interlaboratory testing was conducted to ensure accuracy of the mercury measurements. Concentrations of organic mercury calculated as the difference between total and inorganic mercury as measured by CVAA agreed with those of methylmercury measured on the same samples of hair by GC/AFD. Methylmercury measured by GC/AFD and organic mercury measured by CVAA accounted for over 80% of the total mercury in hair and over 90% of the total mercury in fish muscle. To test the accuracy of recapitulation by hair sampling, hair samples were collected from mothers at the time of delivery and 6 months later. The segment corresponding to the pregnancy term was selected for measurement assuming a hair growth rate of 1.1 cm/month. Results from both samples were in close agreement. As part of both a pilot investigation followed by the main study, maternal hair samples were collected each year from 1986 to 1989 for a total of 1604 samples. The median and mean values for each year's collection fell in the range of 5.9 to 8.2 ppm and exhibited no statistically significant trend with time. The highest recorded concentration was 36 ppm. In hair samples from 654 mothers, the mean concentration of total mercury was compared with the mean concentrations in segments corresponding to each trimester, approximately 3.3 centimeters in length. A high degree of correlation was found between mean levels in each trimester versus the entire pregnancy segment.
在对塞舌尔群岛一个食鱼人群的研究中，孕妇头发中总汞浓度被用作衡量胎儿甲基汞暴露情况的指标。选取孕期生长的一段约10厘米长的头皮头发进行测量。总汞和无机汞采用冷蒸气原子吸收法（CVAA），使用马戈斯试剂进行测量（马戈斯，1971年）。为作比较，在一部分头发样本中，通过X射线荧光光谱法（XRF）测量总汞，通过气相色谱/原子荧光检测法（GC/AFD）测量甲基汞。还对数量有限的鱼类样本进行了分析。开展了广泛的实验室间测试，以确保汞测量的准确性。通过CVAA测量的总汞与无机汞之差计算得出的有机汞浓度，与通过GC/AFD对相同头发样本测量的甲基汞浓度相符。通过GC/AFD测量的甲基汞和通过CVAA测量的有机汞占头发中总汞的80%以上，占鱼肉中总汞的90%以上。为检验通过头发采样重现情况的准确性，在分娩时和6个月后采集母亲的头发样本。假设头发生长速度为每月1.1厘米，选取对应孕期的发段进行测量。两个样本的结果高度一致。作为先导调查及后续主要研究的一部分，在1986年至1989年期间每年采集孕妇头发样本，共1604份。每年采集样本的中位数和平均值在5.9至8.2 ppm范围内，且未显示出随时间的统计学显著趋势。记录到的最高浓度为36 ppm。在654名母亲的头发样本中，将总汞平均浓度与对应每个孕期、长度约3.3厘米的发段中的平均浓度进行了比较。发现每个孕期的平均水平与整个孕期发段之间存在高度相关性。
