Korrick S A, Altshul L
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Environ Health Perspect. 1998 Aug;106(8):513-8. doi: 10.1289/ehp.98106513.
As a consequence of contamination by effluents from local electronics manufacturing facilities, the New Bedford Harbor and estuary in southeastern Massachusetts is among the sites in the United States that are considered the most highly contaminated by polychlorinated biphenyls (PCBs). Since 1993, measures of intrauterine PCB exposure have been obtained for a sample of New Bedford area infants. Among 122 mother-infant pairs, we identified four milk samples with total PCB levels that were significantly higher than the rest, with estimated total PCBs ranging from 1,100 to 2,400 ng/g milk fat compared with an overall mean of 320 ng/g milk fat for the 122 women. The congener profile and history of one case was consistent with past occupational PCB exposures. Otherwise, the source of PCB exposures in these cases was difficult to specify. Environmental exposures including those from fish consumption were likely, whereas residence adjacent to a PCB-contaminated site was considered an unlikely exposure source. In all four cases, the infants were full-term, healthy newborns. Because the developing nervous system is believed to be particularly susceptible to PCBs (for example, prenatal PCB exposures have been associated with prematurity, decrements in birth weight and gestation time, and behavioral and developmental deficits in later infancy and childhood, including decrements in IQ), it is critical to ascertain if breast-feeding is a health risk for the women's infants. Despite the potential for large postnatal PCB exposures via breast milk, there is limited evidence of significant developmental toxicity associated with the transmission of moderate PCB concentrations through breast milk. Breast-feeding is associated with substantial health benefits including better cognitive skills among breast-fed compared with formula-fed infants. We conclude, based on evidence from other studies, that the benefits of breast-feeding probably outweigh any risk from PCB exposures via breast milk among the four New Bedford infants. In this case report, PCB analysis of breast milk and infant cord serum was a research tool. PCB analysis of milk is rarely done clinically, in part because it is difficult to use the results of such analyses to predict health risks. Substantial effort is needed to achieve a better understanding of the clinical and public health significance of PCB exposures, particularly among potentially susceptible groups such as infants and children. Such efforts are critical to improving the clinical and public health management of widespread and ongoing population exposures to PCBs.
由于受到当地电子制造设施排放废水的污染，马萨诸塞州东南部的新贝德福德港及河口是美国被认为多氯联苯（PCBs）污染最严重的地区之一。自1993年以来，已获取了新贝德福德地区婴儿样本的宫内PCB暴露量数据。在122对母婴中，我们发现有4份母乳样本中的总PCB水平显著高于其他样本，估计总PCBs含量在1100至2400纳克/克乳脂肪之间，而这122名女性的总体平均水平为320纳克/克乳脂肪。其中一个案例的同系物特征和既往史与过去的职业性PCB暴露相符。否则，这些案例中PCB暴露的来源很难确定。包括食用鱼类在内的环境暴露很有可能，但居住在受PCB污染场地附近被认为不太可能是暴露源。在这4个案例中，婴儿均为足月出生的健康新生儿。由于发育中的神经系统被认为对PCBs特别敏感（例如，产前PCB暴露与早产、出生体重和妊娠期下降以及后期婴儿期和儿童期的行为和发育缺陷有关，包括智商下降），因此确定母乳喂养是否会对这些女性的婴儿构成健康风险至关重要。尽管通过母乳可能会有大量的产后PCB暴露，但关于通过母乳传播中等浓度PCB会产生显著发育毒性的证据有限。母乳喂养与诸多健康益处相关，包括与配方奶喂养的婴儿相比，母乳喂养的婴儿认知能力更强。基于其他研究的证据，我们得出结论，对于这4名新贝德福德婴儿而言，母乳喂养的益处可能超过通过母乳接触PCB带来的任何风险。在本病例报告中，母乳和婴儿脐带血清的PCB分析是一种研究工具。母乳的PCB分析在临床上很少进行，部分原因是很难利用此类分析结果来预测健康风险。需要付出大量努力以更好地了解PCB暴露的临床和公共卫生意义，尤其是在婴儿和儿童等潜在易感人群中。这些努力对于改善对广泛且持续的人群PCB暴露的临床和公共卫生管理至关重要。
