Ambient black carbon particles reach the fetal side of human placenta

TLDR

Particle transfer across the placenta has been suggested, but no direct evidence in real‑life human context has yet been demonstrated. We report detecting black carbon particles in human placentae using femtosecond‑pulsed white‑light generation. Black carbon particles were found in every examined placenta, with higher loads in mothers exposed to greater ambient levels, and the particles accumulated on the fetal side, indicating that ambient particulates can reach the fetus and may underlie early‑life pollution harms.

Abstract

Abstract Particle transfer across the placenta has been suggested but to date, no direct evidence in real-life, human context exists. Here we report the presence of black carbon (BC) particles as part of combustion-derived particulate matter in human placentae using white-light generation under femtosecond pulsed illumination. BC is identified in all screened placentae, with an average (SD) particle count of 0.95 × 10 4 (0.66 × 10 4 ) and 2.09 × 10 4 (0.9 × 10 4 ) particles per mm 3 for low and high exposed mothers, respectively. Furthermore, the placental BC load is positively associated with mothers’ residential BC exposure during pregnancy (0.63–2.42 µg per m 3 ). Our finding that BC particles accumulate on the fetal side of the placenta suggests that ambient particulates could be transported towards the fetus and represents a potential mechanism explaining the detrimental health effects of pollution from early life onwards.