| Synthetic musks, a kind of emerging pollutants, are frequently used as additivesin cosmetics and personal care products. Because of their lipophilicity, they areexpected to accumulate in human lipid-rich tissues, including breast milk and blood.The main exposure routes of synthetic musks are through percutaneous absorption,which are different from those of organochlorine pesticides. In order to betterunderstand the contaminations of synthetic musks and organochlorine pesticides inhumans, their pollution levels in breast milk, maternal blood and cord blood fromShanghai were analyzed comprehensively in this study. The transfer characteristicswere also studied using paired mother-infant samples.A total of67breast milk,49cord blood,22maternal blood samples werecollected during2006-2010, which including21paired mother-infant samples.8synthetic musk compounds and11organochlorine pesticide compounds, includingdichlorodiphenyltrichloroethane (DDT) and its metabolites DDD and DDE,4isomers of hexachlorocyclohexane (HCH) and hexachlorobenzene (HCB) wereanalyzed. The results showed that these synthetic musks and organochlorinepesticides were ubiquitous in breast milk, maternal blood and cord blood samples.Galaxolide (HHCB) and its metabolite HHCB-lactone, kinds of polycyclic musks,were the main musk contaminants, accounting for66.0%-89.3%of the total muskconcentrations. And4,4’-DDE, the predominant organochlorine pesticide pollutants,accounted for about56.8%-74.7%of the total concentrations. The totalconcentrations ranged from4.7to276.2, from13.5to228.0and from28.3to545.3ng/g lipid weight for synthetic musks in breast milk, maternal blood and cord blood,respectively. The corresponding levels for organochlorine pesticides ranged from88.3to2532.9, from497.5to5737.0, and from248.5to4384.2ng/g lipid weight,respectively. The concentrations of organochlorine pesticides were much higher thanthose of musks in the present study. From a global view, the contamination levels of musks were low in samples from Shanghai, and levels of organochlorine pesticideswere moderate to high, which was higher than those in developed countries, such asEurope, America and Japan or South Korea. The ratio values of DDE/DDTconcentrations in all maternal samples (breast milk and maternal blood) were alllarger than1, excepting in one maternal blood sample, indicated that DDTs weremainly originated from historical application. The correlation analyzed results onconcentrations in breast milk and cord blood suggested different exposure sourcesfor synthetic musks and organochlorine pesticides. This was also supported byprincipal component analysis results on concentration levels in maternal blood.Dietary intake, percutaneous absorption, and respiratory pathway were proposed.The influences of sampling time, mothers’ age and parity on pollution levels ofsynthetic musks and organochlorine pesticides were discussed using statisticalanalysis. The concentrations on different musk compounds in breast milk showeddifferent time changing trends. The relatively high median concentrations of HHCBand HHCB-lactone in2010were detected compared with2006and2008. Thetonalide (AHTN) levels remained fairly constant, whereas musk xylene (MX)concentrations dropping from13.0to9.3ng/g lipid weight was observed during2006-2010. These observations were consistent with musk use patterns, suggestingthe replacement of nitro musks by polycyclic musks. A clear downward temporaltrend in DDTs, HCHs and HCB concentrations (p <0.01) indicated a reduction inhuman body burden in Shanghai, China. There were compound-specificaccumulation patterns of synthetic musks and organochlorine pesticides. A positivecorrelation was observed between the levels of organochlorine pesticides andmother’s age (p <0.05). But for musks, there was no correlationship between residuelevels and age (p>0.05). The age-related influence of organochlorine pesticideaccumulation was only observed in maternal samples. No age-related influence wasfound in organochlorine pesticide concentrations in cord blood samples. Theparity-related influence on organochlorine pesticide levels was also observed in this study (p=0.001), indicating the elimination of organochlorine pesticides viaprevious lactation. The different residue levels of musks may be due to individualuse, instead of maternal age and parity.The popular existing of HHCBs (HHCB+HHCB-lactone), DDTs, HCHs andHCB in breast milk, maternal blood and cord blood, suggested their transfer inhuman body, which was from maternal blood to breast milk, and from maternalblood to cord blood. The ratio values of HHCBs in cord blood/maternal blood werehigher than the ratio values in breast milk/maternal blood in all21paired samples,and the values were significantly higher than1in nearly76%samples. Thisphenomenon may be explained by easily transfer into fetus on HHCBs. Thetransferred amount to breast milk was relatively small, compared to that to cordblood. The ratios of organochlorine pesticides in breast milk/maternal blood andcord blood/maternal blood indicated that their similar transfer amount. The medianconcentration ratio values of HHCBs in cord blood/maternal blood is1.86, whichwas higher than the value of HCB, β-HCH, DDE and DDT (0.54-1.26). Thesignificantly higher transfer ratio of HHCB than that of HHCB-lactone was observedin breast milk and cord blood (p=0.001) The transfer ratio of4,4’-DDE was a littlehigher than that of4,4’-DDT, which was not statistically significant. The resultssuggested that metabolism may affect the transfer characteristics of HHCB and DDT,but the effects were different from each other. The metabolism of HHCB may reduceits transfer level from maternal blood to breast milk or cord blood, while themetabolism of DDT did not significant changed its migrating level. The differenttransfer characteristics may be due to their half-life in humans and physico-chemicalproperties such as logKOW. The concentration correlationship analyses also providedscientific evidences on this difference. The contamination levels on HHCBs inmaternal blood were correlated significantly with that in cord blood (p <0.05), andorganochlorine pesticide concentrations in maternal blood was statistically correlatedwith those in breast milk (p <0.05). Exposure level assessment showed that typical organochlorine pesticides werethe main contaminants for neonates via breast milk, and for fetus in utero, and muskexposure level was considerably low. The mean daily intakes estimated for neonateswere0.1,0.01,0.04,0.01and0.05μg/kg body weight for HHCB, AHTN, MX, MKand HHCB-lactone, respectively. These values were much lower than the estimatedprovisional tolerable daily intakes of500,50,7, and7μg/kg body weight for thesecompounds, respectively. The musks intake via breast milk in neonates was low. Butfor organochlorine pesticides, further attention was needed.85%of neonate intakesexceeded the reference dose (RfD) of the U.S. EPA (4,4’-DDT,0.50μg/kg·day) andthe daily intake of HCHs also exceeded the Canadian provisional tolerable dailyintake (0.3μg/kg body weight) in56%individuals. According to reference data onadults, the exposure level of organochlorine pesticides for fetus in utero was low. Butconsidering the immature metabolic capability and sensitivity of fetus, the pollutionstatus of organochlorine pesticides is still worthy of attention.A method of detection of synthetic musks and organochlorine pesticides inhuman samples was established in this study. The pollution characteristics andinfluence factors of synthetic musks and typical organochlorine pesticides in womenwere discussed, and the exposure amount of fetus in utero and of infants throughbreast milk intakes were also estimated. The transfer characteristics on syntheticmusks and organochlorine pesticides were proposed. Through this study, a largenumber of basic data on exposure assessment of synthetic musks and organochlorinepesticides for infants was provided. And those data, as well as present results, cangive a comprehensive understanding of the differences on pollution and transfercharacteristics, and deepen the studies on human exposure of synthetic musks andorganochlorine pesticides in China. |
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