Occurrence Of Maternal-neonatal Exposure To Persistent Organic Pollutants And Health Risk Assessment

Dichlorodiphenyltrichloroethanes(DDTs),polychlorinated biphenyls(PCBs)and per/polyfluoroalkyl substances(PFASs)are typical persistent organic pollutants(POPs).They have received high-priority concern for the long environmental persistence,biomagnification,and toxicity.Pregnant women and their neonates are the most sensitive population groups to chemical exposure.Since DDTs,PCBs and PFASs were proven to pass through the placental barriers,prenatal exposure frequently occurs in infants whose mothers were exposed to POPs during the pregnancy.Since lipophilic pollutants are easily transferred through breast milk,postnatal exposure frequently occurs in breast-feeding for chemicals from mother to neonates.As we known,fetal exposure to environmental factors plays an important role on the development and other diseases in later life,it is of great significance for assessing the exposure levels of POPs in maternal-neonatal population and evaluating the health risks to our next generations.The main contents and results are as follows:(1)Colostrum and umbilical cord serum samples collected from maternal-neonate pairs(n=106)from the Shengsi Island,located directly downstream from the Yangtze River outlet,were analyzed for DDT isomers and enantiomer compositions,using gas chromatography equipped with mass spectrometer(GC-MS)and GC-MS/MS.The average levels of total DDTs in colostrum and cord serum were 1.93 ± 1.98 and 1.38± 3.66 ?g g-1 lipid weight,respectively.High(DDE+DDD)/DDT and p,p'-DDE/p,p'-DDT ratios suggested that current DDTs residues originated primarily from historical use of DDTs products,but new sources may also contribute partially to some high o,p'-DDT//p,p'-DDT ratios.Maternal age and pregnancy BMI were positively associated with levels of DDTs(p<0.05).An enrichment was found for the(-)-enantiomer of of o,p '-DDD and the(+)-enantiomer of o,p'-DDT,suggesting stereoselective attenuation.After multivariable adjustment,increasing p,p'-DDD and p,p'-DDT level was found significantly associated with increase in neonatal birth weight which deserved additional focus on obesity risk effect.Finally,based on breast milk consumption,the average daily intake of DDTs by neonates was 8.33 ± 7.34 ?g kg-1 bw per day,which exceeded the WHO tolerable daily intake guideline by 25%,implying neonates in this region are potentially at high risk from DDTs exposure.(2)In this cross-sectional study,nine indicator PCBs were detected in both non-invasive samples.The median concentrations of total PCBs in colostrum and cord serum were 71.3 and 35.0 ng g-1 lipid weight.Gestational age was negatively correlated with PCB 52 and 44,while pre-pregnancy BMI was positively correlated with PCB 101.Distribution patterns of PCB180 were significantly different between different maternal age groups and birth gerder.Multivariable linear regression models indicated positive and significant association of PCB 44 between the two matrixes,suggesting the trans-generational transfer of lower-molecule PCB from mothers to neonate.Additionally,in utero exposure to PCB 28,44 and 153 were associated with decreased birth weight.Based on breast milk consumption,the average daily intake of PCBs to neonates was 0.112 ± 0.035 ?g kg-1 bw per day,which exceeded the RfD of ATSDR guideline by 77.4%,implying obvious high risk from exposure to PCBs.(3)This study involved quantitative determination of eleven PFASs in cord serum.PFOS,PFOA,and 6:2 Cl-PFESA were most abundant components with median levels of 4.07,1.05 and 0.731 ng mL-1,respectively.Others were ordered PFHxS>PFNA? PFUnDA ? PFDA>PFDoA>PFHpA>8:2 Cl-PFAES>PFHxA.Statistically higher serum levels were observed in primiparous mothers with advancing maternal age,higher pre-pregnancy BMI,and drinking tap water,which is attributable to the biopersistent properties,exposure and excretion pathway of individual PFASs.Notably,associations between PFOS and adverse birth outcomes were demonstrated,in which 10%increase in the logarithmic-transformed PFOS concentration was associated with a 3.80%and 3.58%declined for birth weight and ponderal index(p<0.01),respectively.PFOS and PFHxS also indicated associations with small for gestational age birth(p<0.05).These findings presented ubiquitous occurrence of emerging PFASs in maternal-neonatal population and improved current understanding of prenatal exposure to these contaminants of emerging concern.