| 2. |
- Chen, Yiqin, et al.
(författare)
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Monthly variation in faeces : blood concentration ratio of persistent organic pollutants over the first year of life
- 2016
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 147, s. 259-268
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have found that the concentrations of a range of persistent organic pollutants (POPs) in faeces is linearly proportional to the POP concentrations in blood of human adults irrespective of age and gender. In order to investigate the correlation between POP concentrations in faeces and blood in infants, the monthly variation of POP concentrations in faeces over the first year of life of one infant was investigated in this study and compared to modelled blood concentrations. Faecal samples were collected from one male infant daily. The samples were pooled by month and analysed for three selected POPs (2,2',4,4',5,5'-Hexachlorobiphenyl (PCB153), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and 2,2',4,4'-tetrabromodiphenyl ether (BDE47)). The POP concentrations in faecal samples increased for the first four months by a factor of 2.9, 4.9 and 1.4 for PCB153, BDE47, and p,p'-DDE, respectively. The faecal concentrations of all POPs decreased rapidly following the introduction of formula and solid food to the diet and subsequent weaning of the infant. Further, a one-compartment model was developed to estimate the daily POP concentrations in the blood of the infant. The POP concentrations in blood were predicted to vary much less over the first year than those observed in faeces. The faeces:blood concentration ratio of selected POPs (K-fb) differed significantly (P < 0.0001) between the period before and after weaning, and observed changes in K-fb are far greater than the uncertainty in the estimated K-fb. A more stable K-fb after weaning indicates the possibility of applying the stable K-fb values for non-invasive assessment of internal exposure in infants after weaning. The intra-individual variation in K-fb in infants is worthy of further investigation.
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| 3. |
- Chen, Yiqin, et al.
(författare)
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Persistent organic pollutants in matched breast milk and infant faeces samples
- 2015
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 118, s. 309-314
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Tidskriftsartikel (refereegranskat)abstract
- Assessing blood concentration of persistent organic pollutants (POPs) in infants is difficult due to the ethical and practical difficulties in obtaining sufficient quantities of blood. To determine whether measuring POPs in faeces might reflect blood concentration during infancy, we measured the concentrations of a range of POPs (i.e. polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs)) in a pilot study using matched breast milk and infant faecal samples obtained from ten mother-child pairs. All infants were breast fed, with 8 of them also receiving solid food at the time of faecal sampling. In this small dataset faecal concentrations (range 0.01-41 ng g(-1) lipid) are strongly associated with milk concentrations (range 0.02-230 ng g(-1) lipid). Associations with other factors generally could not be detected in this dataset, with the exception of a small effect of age or growth. Different sources (external or internal) of exposure appeared to directly influence faecal concentrations of different chemicals based on different inter-individual variability in the faeces-to-milk concentration ratio R-fm. Overall, the matrix of faeces as an external measure of internal exposure in infants looks promising for some chemicals and is worth assessing further in larger datasets.
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