Transport of persistent organic pollutants across the human placenta

Abstract

Prenatal life is the most sensitive stage of human development to environmental pollutants. Early exposure to persistent organic pollutants (POPs) may increase the risk of adverse health effects during childhood. The mechanisms of transference of POPs during pregnancy are still not well understood. The present study is aimed to investigate the transfer of POPs between mother and fetus. The concentrations of 14 organochlorine pesticides, 7 polychlorinated biphenyls (PCBs) and 14 polybromodiphenyl ether (PBDEs) congeners have been measured in 308 maternal serum samples, their respective umbilical cords and 50 placental tissues from a mother-infant cohort representative of Spanish general population. In general, the adjusted lipid-basis concentrations were higher in maternal serum than in cord serum and placenta. The concentrations of most pollutants between maternal serum and cord serum and between maternal serum and placenta were significantly correlated. These distributions were consistent with a predominant maternal source that transfers the pollutants into the placenta and the fetus. However, this distribution did not correspond to passive diffusion of these compounds between these tissues according to lipid content. The compounds more readily metabolized were higher in newborns, which suggest that differences in metabolic capabilities may be responsible of the observed variations in POP distributions between mother and newborns. Prenatal exposure to 4,4'-DDT and some PBDEs such as BDE 99 and BDE 209 is much higher than it could be anticipated from the composition of maternal serum. POP exposure assessment studies of newborns may overlook the effects of some of these pollutants if they only consider maternal determinations.

Effects of Prenatal Exposure to Endocrine Disruptors and Toxic Metals on The Fetal Epigenome

“…While DDT and DDE both have long half-lives in the environment and the human body, DDE was observed to be the predominant form found in pregnant women participating in the National Health and Nutrition Examination Survey [87]. While levels of DDT are lower within fetal than maternal tissues, there is evidence that DDT is actively transported across the placenta as fetal levels are higher than expected via passive diffusion [72]. Prenatal exposure to DDT and DDE has been associated with a range of early and later life health outcomes, including fetal growth measures, adolescent neurodevelopment, indicators of female reproductive functioning, and lung functioning [88][89][90][91][92][93].…”

“…Specifically, exposures to BPA, DDT, PBDE, PCB and phthalates are highlighted. As noted above with respect to toxic metals, all of the endocrine disruptors discussed here are known to cross the placental barrier [71][72][73][74]. The studies detailed below are summarized in Supplementary Table 2. Bisphenol-A BPA, an industrial compound with significant estrogenic effects, is used in a variety of products as a component of polycarbonate plastics or epoxy resins [75].…”

“…Previously used widely as coolants, these chemicals persist in the environment [98]. Research has demonstrated that PCB levels are higher than expected in fetal tissues based on passive diffusion alone, suggesting an active transport mechanism across the placenta [72]. Moreover, biomonitoring of pregnant women suggests that serum levels of PCB may increase over the course of pregnancy as lipid stores are mobilized [99].…”

Prenatal Exposure to Persistent Organic Pollutants and Anogenital Distance in Children at 18 Months

“…These products were added to the list of POPs under the Stockholm Convention in 2009 [2]. Nowadays, their synthesis is severely restricted or banned, but they persist in the environment and in human tissues owing to their high lipophilicity and biomagnifying properties [3-5]. …”

Organochlorine Pollutants within a Polythermal Glacier in the Interior Eastern Alaska Range

“…[28,53,54] This OCP transport may occur within other ablating glaciers of Interior Alaska, raising the possibility that OCP concentration in the ecologically critical Yukon watershed is increasing with ongoing glacial melt. [9,62,[65][66][67][68] Thus, investigations into the reemergence and distribution of OCPs in Arctic glaciers should be prioritized. With the high fish consumption of many Arctic subsistence groups, [24] the risk of toxicity from OCP bioaccumulation is higher than other alpine regions.…”