Brazilian Health Surveillance Agency, University of Brasilia, Brasilia, DF, Brazil; Laboratory of Toxicology, Department of Pharmacy, University of Brasilia, Brasilia, DF, Brazil.
Laboratory of Toxicology, Department of Pharmacy, University of Brasilia, Brasilia, DF, Brazil.
J Trace Elem Med Biol. 2017 Dec;44:99-103. doi: 10.1016/j.jtemb.2017.06.009. Epub 2017 Jul 1.
Mercury is a toxic metal, ubiquitous in nature; it is excreted in breast milk from exposed mothers and may affect infant neuro-development. In this study, 224 breast milk samples provided by eight human milk banks in the Federal District of Brazil were analyzed for total mercury (THg), of which 183 were also analyzed for methyl mercury (MeHg), the most relevant form of this metal for the breastfed infants. Samples were acid digested in a microwave oven and THg determined by atomic fluorescence spectrometry (LOQ of 0.76μg/L). Samples were lyophilized, ethylated and MeHg determined in a MERX automated system (LOQ of 0.10μg/L). Inorganic mercury (IHg) levels were estimated from the THg and MeHg determined in the samples. Most of the samples were collected 1-2 months postpartum, with 38% during the first month. Over 80% of the samples had THg values above the LOQ, reaching a maximum of 8.40μg/L, with a mean of 2.56μg/L. On average, MeHg accounted for 11.8% of THg, with a maximum of 97.4%. Weekly intakes were estimated individually, considering the baby's age and body weight at the time of milk collection. Mean weekly intake for MeHg was 0.16±0.22μg/kg bw, which represented 10% of the PTWI; in only one case, the intake exceeded 100% of the PTWI (1.90μg/kg bw, 119% of PTWI). Mean intake for IHg was 2.1±1.5μg/kg bw, corresponding to 53% PTWI. These results indicate no health concern for the breastfed babies, a conclusion that can be extended to the consumers of breast milk donated to the milk banks, primarily immature and low weight babies.
汞是一种在自然界中普遍存在的有毒金属，会从暴露的母亲的母乳中排出，并可能影响婴儿的神经发育。在这项研究中，分析了来自巴西联邦区 8 个人类母乳库的 224 份母乳样本中的总汞（THg），其中 183 份还分析了甲基汞（MeHg），这是该金属对母乳喂养婴儿最相关的形式。样本在微波炉中进行酸消解，通过原子荧光光谱法（LOQ 为 0.76μg/L）测定 THg。样本经冻干、乙基化，在 MERX 自动化系统中测定 MeHg（LOQ 为 0.10μg/L）。根据样本中测定的 THg 和 MeHg 估算无机汞（IHg）水平。大多数样本是在产后 1-2 个月采集的，其中 38%是在第一个月采集的。超过 80%的样本 THg 值高于 LOQ，最高达 8.40μg/L，平均值为 2.56μg/L。平均而言，MeHg 占 THg 的 11.8%，最高达 97.4%。考虑到采集母乳时婴儿的年龄和体重，分别估算每周的摄入量。MeHg 的平均每周摄入量为 0.16±0.22μg/kg bw，占参考剂量（PTWI）的 10%；仅在一个案例中，摄入量超过了 100%的 PTWI（1.90μg/kg bw，119%的 PTWI）。IHg 的平均摄入量为 2.1±1.5μg/kg bw，相当于 PTWI 的 53%。这些结果表明母乳喂养的婴儿没有健康风险，可以将这一结论推广到母乳库捐赠母乳的消费者，主要是不成熟和低体重的婴儿。
