Internal Exposure Of Phthalates In Pregnant Women In Guangzhou And Their Association With DNA Oxidative Damage

Phthalate esters?PAEs?are a class of synthetic organic chemicals commonly used in a variety of daily consumer products.Inhalation,dietary and skin contact are the three main pathways in which PAEs enter organisms.PAEs may have adverse effects on the health of animals'reproductive system,endocrine system,respiratory system and nervous system.Pregnant women,as a special group,are more sensitive than others and are susceptible to environmental pollutants.Prenatal exposure to PAEs during pregnancy may directly affect the normal growth and development of the fetus,so it is of great significance to carry out studies on exposure of PAEs in pregnant women.In the present study,urinary phthalate metabolites?me-PAEs?were determined as markers in pregnant to indicate human exposure to phthalates.From January 2015 to July2016,a total of 364 pregnant women in different gestational periods were recruited in downtown in Guangzhou,South China.Urine samples as well as questionnaires were collected from the volunteers.Then,the urine was subjected to liquid-liquid extraction pretreatment,and the concentrations of nineteen me-PAEs and 8-hydroxy-2'-deoxyguanosine?8-OHd G?,a deoxyribonucleic acid?DNA?oxidative damage marker,were detected by high performance liquid chromatography tandem mass spectrometry.Based on urinary concentrations of phthalate metabolites,the estimated daily intakes?EDI?of PAEs as well as the potential health risk of them were assessed in pregnant women.Our results indicated that at least one target chemical was found in all urines,suggesting the widespread exposure of PAEs for pregnant women in Guangzhou.Three new me-PAEs,mono-?7-carboxyoctyl?phthalate?m COP?,mono-?6-hydroxy-2-propylheptyl?phthalate?m HPHP?,and mono?3,5,5-trimethyl-1-hexyl?phthalate?m TEHP?were found in more than half of the samples,which indicated that the new PAEs plasticizer has already entered the non-occupational exposed population.The sum concentration of nineteen phthalates(?₁₉PAEs)in pregnant women's urine ranged from 7.28 to 1780 ng/m L with a median 144 ng/m L.Mono-n-butyl phthalate?m BP?,mono-iso-butyl phthalate?mi BP?,and di?2-ethylhexyl?phthalate?DEHP?metabolites were the three main pollutants,and their concentrations were also higher than other phthalates in this study.The profiles were likely related to the continuous exposure through consumer products.Compared with traditional me-PAEs,the concentration of new me-PAEs was about two orders of magnitude lower in pregnant women,which indicated that the new PAEs plasticizer in use has not yet entered the human body in large quantities.Compared with studies in global range,PAEs exposure in pregnant women was at a moderate level in Guangzhou,and industrial pollution may be the main cause of differences in me-PAEs concentrations in similar populations from different countries.A relative strong or moderate but significant positive correlation was found between concentrations of 8-OHd G and the traditional me-PAEs,reflecting the possible associations of PAEs exposure with oxidative stress and DNA oxidative damage.The correlation between the new me-PAEs and 8-OHd G was low and significantly weaker than those between traditional me-PAEs and 8-OHd G,which indicated that the oxidative effect caused by the new PAEs might be less.This result also indicated that new PAEs are some plasticizers with less toxicity and will have great development prospects in the future.For exposure doses,among the seven PAEs evaluated,the highest EDI was for di-n-butyl phthalate?DBP??median:2.47?g/kg bw/day?,followed by diisobutyl phthalate?Di BP??1.64?g/kg bw/day?and DEHP?0.93?g/kg bw/day?,which were far less than the tolerable daily intakes recommended by the authorities,so the daily exposure of PAEs for pregnant women in Guangzhou is low.In addition,the calculated hazard quotient?HQ?and hazard index?HI?in a small number of pregnant women was higher than 1.0,which indicated they may have potential health risk introduced by exposure to phthalates.