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Breast-feeding exposure of infants to cadmium, lead, and mercury: A public health viewpoint

Division of Toxicology, Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Services, Atlanta, Georgia 30333, USA.
Toxicology and Industrial Health (Impact Factor: 1.71). 07/1997; 13(4):495-517. DOI: 10.1177/074823379701300403
Source: PubMed

ABSTRACT The purpose of this report is to provide an overview of the public health implications of exposure via breast milk to cadmium, lead, and mercury for nursing infants and to provide health-based guidance. Daily intakes were calculated and compared with guidance values used for public health assessments at hazardous waste sites. Cadmium, lead, and mercury under normal conditions are found in breast milk at concentration ranges of < 1 microgram/L, 2-5 micrograms/L, and 1.4-1.7 micrograms/L, respectively. Women exposed environmentally or occupationally can have higher levels in their breast milk. Concentrations of about 5 micrograms/L (cadmium), 20 micrograms/L (lead), and 3.5 micrograms/L (mercury) appear to be adequate screening levels. Many factors affect both the distribution of cadmium, lead, and mercury in breast milk and the health consequences to an infant. It is not clear what additional impact low-level exposure via breast milk may have on an infant born with a body burden to one of these metals. There is sufficient evidence to make the case that contaminated breast milk is a source of potential risk to infants in certain populations. Prevention strategies that include behavior modification and proper nutrition should be communicated to women at risk. Identification and elimination of exposure pathways and a critical analysis of the benefits of breast feeding versus heavy metal exposure are needed on a site-specific or individual basis. Research is required to better understand the impact of low-level exposure to heavy metals via breast milk. Breastfeeding should be encouraged under most circumstances.

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    • "Because maternal blood is the matrix from which lead is transferred to breast milk and, ultimately, to the breastfeeding infant, the relationship of lead in maternal blood and in breast milk is of key importance. Early studies supported the belief that human milk levels were one-tenth to one-fifth the levels of lead in maternal blood (Abadin et al. 1997). However, Gulson et al. (1998a) and Amarasiriwardena et al. (2013) have discussed in detail the analytical difficulties of quantifying lead in breast milk. "
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    ABSTRACT: Human milk is a potential source of lead exposure. Yet, lactational transfer of lead from maternal blood into breast milk and its contribution to infant lead burden remains poorly understood. We explored the dose-response relationships between maternal blood, plasma, and breast milk to better understand lactational transfer of lead from blood and plasma into milk and, ultimately, to the breastfeeding infant. We measured lead in 81 maternal blood, plasma, and breast milk samples at 1-month postpartum and in 60 infant blood samples at 3 months of age. Milk-to-plasma (M/P) lead ratios were calculated. Multivariate linear, piecewise, and generalized additive models were used to examine dose-response relationships between blood, plasma, and milk lead levels. Maternal lead levels (mean ± SD) were: blood: 7.7 ± 4.0 µg/dL; plasma: 0.1 ± 0.1 µg/L; milk: 0.8 ± 0.7 µg/L. Average M/P lead ratio was 7.7 (range 0.6 - 39.8) with 97% of the ratios being greater than 1. The dose-response relationship between plasma lead and M/P ratio was nonlinear (EDF = 6.5, p-value = 0.0006) with M/P ratio decreasing by 16.6 and 0.6 per 0.1 µg/L of plasma lead, respectively, below and above 0.1 µg/L plasma lead. Infant blood lead (3.4 ± 2.2 µg/dL) increased by 1.8 µg/dL per 1 µg/L milk lead (p-value < 0.0001, R(2) = 0.3). The M/P ratio for lead in humans is substantially higher than previously reported and transfer of lead from plasma to milk may be higher at lower levels of plasma lead. Breast milk is an important determinant of lead burden among breastfeeding infants.
    Environmental Health Perspectives 11/2013; 122(1). DOI:10.1289/ehp.1307187 · 7.98 Impact Factor
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    • "Usually, authors report values less than 1 mg/L (Sternowsky et al. 2002), while in samples from highly polluted areas 17 mg/L was reported (Dewey 1998). Values of 0.196 + 0.03 mg/L obtained in our study indicates very low exposure to As. Cadmium, mercury, and lead under normal conditions are found in breast milk at concentration ranges of ,1 mg/L, 1.4– 1.7 mg/L, and 2 – 5 mg/L, respectively (Abadin et al. 1997). In our study, concentrations of cadmium, mercury, and lead were 0.27 + 0.04 mg/L, 0.115 + 0.05 mg/L, and 1.51 + 0.32 mg/L, respectively, which is in accordance with values published by Honda (Honda et al. 2003) and Leotsinidis (Leotsinidis et al. 2005). "
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    ABSTRACT: This article maybe used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
    Analytical Letters 02/2008; 41(3). DOI:10.1080/00032710701862910 · 0.98 Impact Factor
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    • "MeHg forms accounted for about 7–50% of total mercury (Abadin et al., 1997). "
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