Using non-targeted screening and silicone wristbands to investigate geographic differences in pollution exposures among maternal and cord sera

BACKGROUND AND AIM: Differential risk for adverse pregnancy outcomes in the Fresno and San Francisco regions of California may be influenced by chemical exposures in pregnant women that are not fully captured by traditional biomonitoring approaches. We compared multiple exposure assessment approaches and evaluated differences in chemical exposures among a cohort of pregnant women between the two locations. METHODS: We recruited 300 San Francisco and 75 Fresno mothers and collected maternal and cord sera which we screened for over 2,420 chemicals using high-resolution mass spectrometry using liquid chromatography – quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). 26 of the Fresno participants wore silicone wristbands, which were screened for over 1,500 chemicals using targeted chemical analysis. We matched 75 San Francisco participants to the Fresno participants and used Fisher’s exact test to compare detection frequencies of chemicals in maternal and cord sera between the two locations. We also evaluated whether mothers living in Census tracts with high levels of pollution or pesticides according to CalEnviroScreen had significantly higher numbers of chemicals detected in their sera using Spearman’s rank correlation. RESULTS:We detected 2,167 features across the maternal and cord sera samples by the non-targeted approach. The numbers of suspect chemical features detected were not significantly different between San Francisco and Fresno. A higher number of chemicals tentatively identified as cosmetics or fragrances were significantly differentially detected among the Fresno participants (p0.05). The silicone wristbands also showed high levels of several chemicals used in fragrances, including ethylene brassylate, benzyl salicylate, tonalide, beta-ionone, and lilial. Fresno participants living in tracts with higher pesticide scores had significantly higher numbers of suspect pesticides in their sera (p0.05). CONCLUSIONS:Multiple exposure assessment approaches demonstrate the broad array of chemicals women are exposed to during pregnancy. Many of these chemicals have not been well-studied in terms of their effects on human health. KEYWORDS: exposome, reproductive outcomes, environmental disparities