Recent studies in experimental animals found that oral exposure to micro- and nano-plastics (MNPs) during pregnancy had multiple adverse effects on outcomes and progeny, although no study has yet identified the translocation of ingested MNPs to the placenta or fetal tissues, which might account for those effects. We therefore assessed the placental and fetal translocation of ingested nanoscale polystyrene MNPs in pregnant rats. Sprague Dawley rats (N = 5) were gavaged on gestational day 19 with 10 mL/kg of 250 µg/mL 25 nm carboxylated polystyrene spheres (PS25C) and sacrificed after 24 h. Hyperspectral imaging of harvested placental and fetal tissues identified abundant PS25C within the placenta and in all fetal tissues examined, including liver, kidney, heart, lung and brain, where they appeared in 10–25 µm clusters. These findings demonstrate that ingested nanoscale polystyrene MNPs can breach the intestinal barrier and subsequently the maternal–fetal barrier of the placenta to access the fetal circulation and all fetal tissues. Further studies are needed to assess the mechanisms of MNP translocation across the intestinal and placental barriers, the effects of MNP polymer, size and other physicochemical properties on translocation, as well as the potential adverse effects of MNP translocation on the developing fetus.

Genistein is a natural phytoestrogen of the soybean, and bisphenol A (BPA) is a synthetic chemical used in the production of polycarbonate plastics. Both genistein and BPA disrupt the endocrine system in vivo and in vitro. Growing concerns of altered xenobiotic metabolism due to concomitant exposures from soy milk in BPA-laden baby bottles has warranted the investigation of the glucuronidation rate of genistein in the absence and presence (25 μM) of BPA by human liver microsomes (HLM) and rat liver microsomes (RLM). HLM yield V_max values of 0.93 ± 0.10 nmol · min⁻¹ · mg⁻¹ and 0.62 ± 0.05 nmol · min⁻¹ · mg⁻¹ in the absence and presence of BPA, respectively. K_m values for genistein glucuronidation by HLM in the absence and presence of BPA are 15.1 ± 7.9 μM and 21.5 ± 7.7 μM, respectively, resulting in a K_i value of 58.7 μM for BPA. Significantly reduced V_max and unchanged K_m in the presence of BPA in HLM are suggestive of noncompetitive inhibition. In RLM, the presence of BPA resulted in a K_i of 35.7 μM, an insignificant change in V_max (2.91 ± 0.26 nmol · min⁻¹ · mg⁻¹ and 3.05 ± 0.41 nmol · min⁻¹ · mg⁻¹ in the absence and presence of BPA, respectively), and an increase in apparent K_m (49.4 ± 14 μM with no BPA and 84.0 ± 28 μM with BPA), indicative of competitive inhibition. These findings are significant because they suggest that BPA is capable of inhibiting the glucuronidation of genistein in vitro, and that the type of inhibition is different between HLM and RLM.

A method of employing an ion chromatography (IC) column, an online post-column cold vapor (CV) generation system, coupled to an inductively coupled plasma mass spectrometer (ICP-MS), for the determination of inorganic mercury (Hg²⁺) and monomethylmercury (CH₃Hg⁺) is described. The IC-CV-ICP-MS technique has generated a method with significant improvements in detection limits as well as shorter analysis time over previous methods. In addition, several major shortcomings associated with the conventional pneumatic nebulization system, e.g., high reflected power from organic solvent introduction into the plasma, deposition of carbon on the sampler and skimmer cones and significant memory effect, have been minimized. The analysis run was finished in as little as six minutes with a mobile phase of 65% methanol and 0.45 M hydrochloric acid. The detection limits (as Hg), based on three times the standard deviation of a standard solution, were found to be 35 pg mL⁻¹ for Hg²⁺ and 73 pg mL⁻¹ for CH₃Hg⁺, with an injection volume of 400 µL. The proposed method was applied to mercury speciation analysis in two soil samples and compared with IC-ICP-MS using conventional pneumatic nebulization for sample introduction. Good agreement was obtained between the two methods. The analysis of extracts from soil samples spiked of Hg²⁺ and CH₃Hg⁺ with this method showed recoveries of close to 100% for both species.

The use of Bisphenol A (BPA) has widely been replaced in consumer products by analogs BPB, BPE, BPF, BPS, and BPAF. Recent studies have linked these substitutes to similar adverse health outcomes as BPA, including disruption of endocrine pathways in animal and human studies. We designed a novel MS method, developed specifically for this study, to capture the most relevant BPA alternatives, BPB, BPE, BPF, BPS, BPAF and 4-NP in human blood and urine to quantify potential in utero exposures. To our knowledge, this is the first study to explore in utero exposure to these BPA analogs and the first U.S. study to test for BPA in maternal/fetal pairs. The method was run on 30 paired maternal urine and fetal cord blood samples from mothers undergoing elective Caesarean sections. 90% of mothers and 77% of babies tested positive for at least one BP analog. 83% of mothers tested positive for BPAF, 60% for BPS, 57% for BPB, 17% for BPF and 7% for BPA. 57% of babies tested positive for BPAF and 50% for BPF. BPA and BPB were detected in one cord blood sample each. BPS was not detected in cord blood. BPE was not detected in any fetal cord blood or maternal urine samples. These findings demonstrate the pervasiveness of some BP analogs in pregnant women and their babies at birth.