| 1. |
- Dai, Qingyuan, et al.
(författare)
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Severe dioxin-like compound (DLC) contamination in e-waste recycling areas : An under-recognized threat to local health
- 2020
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 139
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Tidskriftsartikel (refereegranskat)abstract
- Electrical and electronic waste (e-waste) burning and recycling activities have become one of the main emission sources of dioxin-like compounds (DLCs). Workers involved in e-waste recycling operations and residents living near e-waste recycling sites (EWRS) are exposed to high levels of DLCs. Epidemiological and experimental in vivo studies have reported a range of interconnected responses in multiple systems with DLC exposure. However, due to the compositional complexity of DLCs and difficulties in assessing mixture effects of the complex mixture of e-waste-related contaminants, there are few studies concerning human health outcomes related to DLC exposure at informal EWRS. In this paper, we have reviewed the environmental levels and body burdens of DLCs at EWRS and compared them with the levels reported to be associated with observable adverse effects to assess the health risks of DLC exposure at EWRS. In general, DLC concentrations at EWRS of many countries have been decreasing in recent years due to stricter regulations on e-waste recycling activities, but the contamination status is still severe. Comparison with available data from industrial sites and well-known highly DLC contaminated areas shows that high levels of DLCs derived from crude e-waste recycling processes lead to elevated body burdens. The DLC levels in human blood and breast milk at EWRS are higher than those reported in some epidemiological studies that are related to various health impacts. The estimated total daily intakes of DLCs for people in EWRS far exceed the WHO recommended total daily intake limit. It can be inferred that people living in EWRS with high DLC contamination have higher health risks. Therefore, more well-designed epidemiological studies are urgently needed to focus on the health effects of DLC pollution in EWRS. Continuous monitoring of the temporal trends of DLC levels in EWRS after actions is of highest importance.
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| 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 infants and toddlers : Relationship between concentrations in matched plasma and faecal samples
- 2017
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 107, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- Early-childhood biomonitoring of persistent organic pollutants (POPs) is challenging due to the logistic and ethical limitations associated with blood sampling. We investigated using faeces as a non-invasive matrix to estimate internal exposure to POPs. The concentrations of selected POPs were measured in matched plasma and faecal samples collected from 20 infants/toddlers (aged 13 +/- 4.8 months), including a repeat sample time point for 13 infants (similar to 5 months apart). We observed higher rates of POP quantification in faeces (2 g dry weight) than in plasma (0.5 mL). Among the five chemicals that had quantification frequencies over 50% in both matrices, except for HCB, log concentration in faeces (C-f) and blood (C-b) were correlated (r > 0.74, P < 0.05) for p.p'-dichlorodiphenyldichloroethylene (p,p'-DDE), 2,3', 4,4', 5-pentachlorobiphenyl (PCB118), 2,2', 3,4,4', 5'-pentachlorobiphenyl (PCB138) and 2,2', 4,4', 5,5'-pentachlorobiphenyl (PCB153). We determined faeces: plasma concentration ratios (K-fb), which can be used to estimate C-b from measurements of C-f for infants/toddlers. For a given chemical, the variation in K-fb across individuals was considerable (CV from 0.46 to 0.70). Between 5% and 50% of this variation was attributed to short-term intra-individual variability between successive faecal samples. This variability could be reduced by pooling faeces samples over several days. Some of the remaining variability was attributed to longer-term intra-individual variability, which was consistent with previously reported observations of a decrease in K-fb over the first year of life. The strong correlations between C-f and C-b demonstrate the promise of using faeces for biomonitoring of these compounds. Future research on the sources of variability in K-fb could improve the precision and utility of this technique.
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| 4. |
- 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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