46 phosphorus FRs (11 alkyl, 24 aryl, 11 chlorinated) were experimentally screened for placentation – disrupting effects, by inhibition of proliferation of human trophoblast cells. Three aryl phosphates, of the 46 tested OPFRs, showed disruption potential in the screening (EHDPP = 2-Ethylhexyl diphenyl phosphate CAS 1241-94-7, o-TCrP = Tri-O-cresyl phosphate CAS 78-30-8, B4tBPPP = Bis(p-tert-butylphenyl) phenyl phosphate CAS 115-87-7). Of these three, EHDPP was selected for further testing because it has been detected in soil, dust, water and food. In a 10-day in vitro test, EHDPP interfered with the insulin-like growth factor 1 receptor protein (IGF1R), inhibiting aerobic cell respiration and so villous cytotrophoblasts (VCT) cell proliferation. Animal tests using female mice, exposed to EHDPP at 0 – 10 mg/kg body weight/day before and during pregnancy showed placental disorders, with related failures of pregnancy, reduced fetal growth and impaired glucose tolerance.
“Screening of Organophosphate Flame Retardants with Placentation-Disrupting Effects in Human Trophoblast Organoid Model and Characterization of Adverse Pregnancy Outcomes in Mice”, C. Xu et al., Environmental Health Perspectives 057002-1, 130(5) May 2022 https://doi.org/10.1289/EHP10273