| Plasticizers,organochlorine pesticides and polycyclic aromatic hydrocarbons are the organic pollutants that widespread in the environment with different physicochemical properties and pose a potential hazard to humans,living beings,properties,and the environment itself.Currently,the method of human biomonitoring was widely used to evaluate the internal exposure concentration of hazardous substances in human bodies.Fetus in the womb is a very sensitive period for exposure.The Barker hypothesis suggests that the effects of exposure during gestational times may lead to negative health effects after birth or even adulthood.Some studies have reported that those xenobiotic hazardous substances have the ability to enter the cord blood circulations and direct exposure to the fetus.However,the research on how those material get transported through the placenta is still very scarce.After the hazardous substances enter the fetal blood circulation,the endocrine disrupting substances(EDCs)may affect the hypothalamic-pituitary-gonadal axis(HPG axis)of the fetus,thereby affecting its endocrine level and regulating the secretion of sex hormones.Therefore,the goal of this study is to investigate of the exposure level of environmental hazardous substances,to establish a valid human biomonitoring method for human biomonitoring studies,and to study the level of fetal exposure to environmental hazardous substances and their exposure mechanisms,and a step further,to investigate the adverse health effects of hazardous substances on the fetus.Those topics have extremely important scientific and practical significance in the field of environmental health.The results of this paper are as follows:(1)In this chapter,a human biomonitoring method using hair as a sample matrix was established and validated.A small-scale pilot human biomonitoring experiment was also conducted.This method meets the precision and accuracy standards issued by the European Medicine Agency(EMA)guidelines and have the ability to accurately evaluate 10 of 11 biomarkers for 4 novel alternative plasticizers.The result for pilot biomonitoring experiment indicated more hydrophobic primary monoester metabolites are easier to detect than the more hydrophilic secondary metabolites.Hair is a matrix with adequate ability to retain and store AP metabolites from the blood circulation and can be used as a biological matrix for exposure assessment of human for alternative plasticizers.It may have greater application value when studying exposure to vulnerable or difficult to sample populations,such as newborns and you ng children.(2)In this chapter,the human biomonitoring method developed in the previous chapter was expanded and validated to cover both phthalate ester and alternative plasticizer metabolites.Using hair segments samples from patients under observation in ICU to investigate the potential nosocomial plasticizer exposure from medical devices.The results show that the concentration of the biomarkers in the hair segments increased alo ng with the time of ICU hospitalization time.Amo ng all the metabolites,MEP,MEHP and MEHTP could be related to nosocomial plasticizer exposure,and other quantifiable metabolites could be the results for the background plasticizer exposure in that area.(3)In this chapter,79 pairs of mother-infants volunteers were recruited from Wuhan,Hubei,China.The concentration of typical OCPs,the HCH and the DDT were quantified in matched samples of maternal serum,placenta and cord serum.The transplacental efficiency was calculated using concentration ratios on both sides of the placenta(Rem).The correlations between the concentration in matrices,the transplacental transfer efficiency and the potential impact factors were evaluated using Pearson correlation analysis.OCP lipid adjusted concentration was found in the three biological matrices:maternal serum>cord serum>placenta,with ?-HCH and p,p'-DDE being the predominant contaminant species.The study found a significant negative correlation between parity and pollutant concentration;other factors such as maternal age were also related to the exposure of pollutants in the body,but the correlation was not universal.The study found that the chiral contaminants a-HCH,o,p '-DDD and o,p '-DDT were non-racemic in all three biological samples.Wherein EF a-HCH<0.5,EFo,p'-DDD<0.5,EFo,p'-DDT>0.5.The HCH and DDT exhibit different transplacental transport characteristics.For HCH,the Rem<1,while for DDT,the Rcm?1,indicates the transplacental transport efficiency of different pollutants is related to the physicochemical properties or depending on different transport mechanisms.(4)In this chapter,the mechanism of transplacental transport of typical organochlorine pesticides(HCH and DDT)was studied using BeWo chorionic epithelial cell membrane in vitro placental model.It was found that HCH and DDT reached concentration equilibrium after exposed in pesticides for 180 minutes,HCH showed higher apparent transport efficiency in the intake direction than DDT;the efflux direction showed higher transport efficiency than the intake direction.Results show HCH is more difficult to pass through the placental membrane,which is consistent with the experimental results of biomonitoring samples.Transport inhibition experiment has observed that ABC transporter family inhibitors and metabolic inhibitors can significantly reduce the transport efficiency of OCP across BeWo cell membranes,confirming that OCP transplacental transfer is the result of active transport of multiple transporters alo ng with lipophilic substances across phospholipids by passive diffusion transport of molecular layers.(5)In this chapter,maternal exposure of polycyclic aromatic hydrocarbon(PAHs)in 109 cord serum samples from She ngsi Islands,Zhoushan City was using the human biomonitoring method.An ELISA analysis was applied to investigate the sex hormone levels in the same group of samples.The total concentration of 16 PAHs was found to be 164(IQR 93.6-267)ng g-1 lipid,the main component was L-PAHs.The dietary intake route is the main route of exposure for the study population.There was no correlation between the total concentration of 16-PAHs and the concentration of H-PAHs in cord blood and the potential influencing factors;while L-PAHs were significantly correlated with gender of the baby,parity,pregnancy weight gain,the number of abortions.Sex hormone in cord serum was found not significantly correlated with those factors.The PAHs exposure was found to be negatively correlated with E2 and AMH levels in cord blood and positively correlated with FSH levels.This alteration in sex hormone levels may be related to the negative feedback regulation of the HPG axis. |
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