Exposure Levels of Environmental Endocrine Disruptors in Mother-Newborn Pairs in China and Their Placental Transfer Characteristics

Lu-Xi Li,Yuan Liang,Xiang-Zhou Meng,Bing-Heng Chen,Yan Zhao,Yun-Hui Zhang,Li Chen,Shang-Qin Chen,Li-Fang Zhao,Qinghua Sun

doi:10.1371/journal.pone.0062526

Abstract

There is a growing concern about the potential health effects of exposure to various environmental chemicals during pregnancy and infancy. The placenta is expected to be an effective barrier protecting the developing embryo against some endocrine disruptors (EDs) circulating in maternal blood. The current study was designed to assess in utero exposure levels of non-persistent organic pollutants (non-POPs) and persistent organic pollutants (POPs) in Chinese newborns and potential role of placenta barrier against fetal exposure to these commonly-used environmental endocrine disruptors. A total of 230 newborn-mother pairs were enrolled during 2010–2011, 201 pairs of which were recruited from Shanghai, and the other 29 pairs came from Wenzhou. Maternal blood, cord blood, and meconium specimens were collected in the subject population from Shanghai and analyzed for non-POPs, including mono-2-ethylhexyl phthalate (MEHP), octylphenol (OP) and 4-nonylphenol (4-NP). A total of 19 polybrominated diphenyl ethers (PBDEs) congeners, which belong to POPs, were detected in maternal and cord blood specimens from the other 29 pairs. Fetal-maternal ratios (F-M ratios) and regression coefficients were presented to assess potential function of placenta on barricading the mother/fetal transfer of these EDs. Concentrations of the detected non-POPs in cord blood samples were approximately 20% lower than those in maternal blood, and regression coefficients of which were all over 0.80. In contrast, PBDEs levels in cord blood samples were significantly higher than those in maternal blood. MEHP levels in meconium were much higher than those in cord blood samples, and highly correlated. Therefore, observations demonstrated that the placental barrier slightly decreased the fetal exposure to most non-POPs, while PBDEs seemed to be totally transferred across the placenta and finally reached the fetus. For in utero exposure assessment of Di-2-ethylhexyl phthalate (DEHP), MEHP level in meconium may be a useful biomarker.

Highlights

Endocrine disruptors (EDs) are ubiquitous in environment matrix and human bodies
Mono-2-ethylhexyl phthalate (MEHP), octylphenol (OP), 4-nonylphenol (4-NP) and polybrominated diphenyl ethers (PBDEs) have been detected in physiologically relevant compartments within pregnant women and the developing fetuses, such as maternal urine, cord blood, breast milk, meconium, placenta, and amniotic fluid in several studies from Europe, the United States of America (USA), and Asia [1,2,3,4,5,6,7], showing that pregnant women and their fetuses are exposed to those chemicals
MEHP, OP and 4-NP were found in more than 65% maternal and cord blood samples in our study, indicating widespread human exposure to these non-persistent organic pollutants (POPs) in Shanghai and confirming that human exposure to these chemicals can begin in utero

Summary

Introduction

Endocrine disruptors (EDs) are ubiquitous in environment matrix and human bodies. There is a growing concern about the potential health effects of exposure to various environmental chemicals during pregnancy and infancy. Mono-2-ethylhexyl phthalate (MEHP), octylphenol (OP), 4-nonylphenol (4-NP) and polybrominated diphenyl ethers (PBDEs) have been detected in physiologically relevant compartments within pregnant women and the developing fetuses, such as maternal urine, cord blood, breast milk, meconium, placenta, and amniotic fluid in several studies from Europe, the United States of America (USA), and Asia [1,2,3,4,5,6,7], showing that pregnant women and their fetuses are exposed to those chemicals These environmental EDs, released into the environment through production and usage, are known to mimic or antagonize hormonal activities at trace concentrations. Fetal exposure to EDs has been associated with functional developmental effects [9], and eventually may adversely affect their reproductive and hormonal systems, as well as cause cancer

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Results

Conclusion