Prenatal And Postnatal Exposure Assessment And Maternal-fetal Transmission Of Synthetic Phenolic Antioxidants

Synthetic phenolic antioxidants?SPAs?are a type of anthropogenic additives widely used in various daily necessities and industrial products,whose potential for toxicity has received widespread concerns in recent years.SPAs have been widely detected in food,dust,sewage sludge and other environmental matrices,this substance can be further exposed to the human body through dietary intake,dust ingestion and dermal exposure,and may cause potential health risks to human body.Although SPAs can reach humans through many exposure pathways,few data on the concentrations of SPAs in humans are available,especially on the exposure of sensitive groups such as pregnant women and infants to these synthetic chemicals.In this study,we selected the sensitive group of pregnant women and infants in Guangzhou as the research object,and the new organic pollutant SPAs were selected as target compounds.The study was systematically analyzed the composition profiles and the transfer across the placenta of target compounds in matched maternal plasma,cord plasma,and placenta from a population of pregnant women.In addition,the association of concentrations with the Mothers'demographic and lifestyle characteristics and newborn birth outcomes,and the potential exposure of infants to multiple antioxidants through breast feeding.The main conclusions of this study are as follows:Five target SPAs and all four target?transformation products?TPs of 2,6-di-tert-butyl-hydroxytoluene?BHT?were frequently detected in the maternal-placental-fetal unit,indicating prenatal exposure to SPAs and the transfer of SPAs across the placenta.In the three matrices,BHT,2,4-di-tert-butylphenol?DBP?,and 2,2-methylenebis?4-methyl-6-tert-butylphenol??AO 2246?were identified as the most abundant SPAs,while 2,6-di-tert-butyl-1,4-benzoquinone?BHT-Q?and 2,6-di-tert-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone?BHT-quinol?were identified as the predominant TPs of BHT.In the maternal plasma,concentrations of both BHT-Q and BHT-quinol were significantly correlated with BHT?p<0.001?,suggesting that the two TPs mainly originated from the biotransformation of BHT itself in pregnant women.The transplacental transfer efficiencies?TTEs?of the SPAs and TPs were structure-dependent and generally less than 1.Significantly higher TTEs for four target TPs than their parent BHT were identified.All target SPAs and TPs were detected in the breast milk samples.DBP was detected at high concentrations(mean of 16.9 ng m L^-1),followed by BHT(mean of1.52 ng m L^-1).DBP and BHT collectively contributed to 91.9%of the mean?SPAs?sum concentrations of all detected SPAs?.The lipid content was identified as an important endogenous factor that influenced the levels of DBP and BHT in breast milk.The concentrations of BHT,DBP,and?TPs?sum concentrations of all four detected TPs?in the breast milk were significantly associated with maternal education level,eating habits,and personal care product use?p<0.05?.Furthermore,the concentrations of BHT and its TPs in the breast milk were also found to be significantly associated with newborn birth outcomes,including prematurity and birth length?p<0.05?.The<1-month-old infant group had the highest exposure risk,and their estimated daily intake values?EDIs?of BHT,DBP,?SPAs,and?TPs under the high-end exposure scenario were up to 672,5850,6600,and 750 ng kg^-1 bw day^-1,respectively.And the EDIs decreased with an increase in infant age due to decreasing daily ingestion rate?MIR?with increasing infant body weight.