| 1. |
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| 2. |
- Fu, Jianjie, et al.
(författare)
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Temporal trends (2005-2009) of PCDD/Fs, PCBs, PBDEs in rice hulls from an e-waste dismantling area after stricter environmental regulations
- 2012
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 88:3, s. 330-335
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Tidskriftsartikel (refereegranskat)abstract
- Primitive e-waste dismantling activities have been of increasing concern due to serious environmental and human health problems, and therefore authorities in China have strengthened the regulations on illegal e-waste recycling activities. In this work, we used rice hull as a passive sampler and investigated temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) in areas near e-waste recycling sites after the stricter regulations. Furthermore, the distribution patterns and composition profiles of these contaminants were also discussed. The average concentrations of the three groups of persistent organic pollutants (POPs) in rice hulls have markedly decreased during the period of 2005-2009. Specifically, from 12.9 (average value in 2005) to 0.37 pg WHO-TEQ/g (dry weight, dw) (in 2009) for PCDD/Fs, 47.6 (2005) to 7.10 ng g(-1)dw (2009) for PCBs, and 2.51 (2005) to 0.89 ng g(-1), dw (2009) for PBDEs. The significant decrease of combustion markers 2,3,4,7,8-PeCDF, 1,2,3,6,7,8HxCDF and PCB126, and the PCDD/PCDF ratio from 1:9 (2005) to 7:3 (2009) is likely a result of stricter regulations on open combustion activities. This study suggests that stricter control measures, strengthened laws and regulations and more environmental friendly techniques could be effective measures in reducing the release and formation of related POPs in typical e-waste dismantling sites, and these measures could further improve the quality of the environment and health of the local inhabitants.
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| 3. |
- Hao, Yanfen, et al.
(författare)
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Air monitoring of polychlorinated biphenyls, polybrominated diphenyl ethers and organochlorine pesticides in West Antarctica during 2011-2017 : Concentrations, temporal trends and potential sources
- 2019
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 249, s. 381-389
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Tidskriftsartikel (refereegranskat)abstract
- Annual air samples were collected at various sites in the Fildes Peninsula, West Antarctica from December 2010 to January 2018 using XAD-2 resin passive air samplers to investigate concentrations, temporal trends and potential sources of persistent organic pollutants (POPs) in Antarctic air. Relatively low concentrations of polychlorinated biphenyls (PCBs) (Σ19PCBs: 1.5-29.7 pg/m3), polybrominated diphenyl ethers (PBDEs) (Σ12PBDEs: 0.2-2.9 pg/m3) and organochlorine pesticides (OCPs) (Σ13OCPs: 101-278 pg/m3) were found in the atmosphere of West Antarctica. PCB-11, BDE-47 and hexachlorobenzene (HCB) were the predominant compounds in the atmosphere. The concentrations of PCBs, HCHs, DDTs and endosulfans were found to show decreasing temporal trends, whereas uniform temporal trends were observed for HCB. The atmospheric half-life values for PCBs, HCHs, DDTs and endosulfans in Antarctic air were estimated for the first time, using regressions of the natural logarithm of the concentrations versus the number of years, obtaining the values of 2.0, 2.0, 2.4 and 1.2 year, respectively. An increasing ratio of α-HCH/γ-HCH indicated long residence time for α-HCH and possible transformation of γ-HCH to α-HCH in the atmosphere. The ratios of p,p'-DDT/p,p'-DDE were mostly lower than unity in this study, which could be attributed to aged sources. It was found that long-range atmospheric transport was still considered to be the main contributing factor to the atmospheric levels of the POPs in West Antarctica whereas the contribution of human activities at the Chinese Great Wall Station was minor. The results of this study give a view on the most recent temporal trends and provide new insights regarding the occurrence of various POPs in the Antarctic atmosphere.
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| 4. |
- Li, Honghua, et al.
(författare)
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Levels and distribution of hexabromocyclododecane (HBCD) in environmental samples near manufacturing facilities in Laizhou Bay area, East China
- 2012
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry (RSC). - 1464-0325 .- 1464-0333. ; 14:10, s. 2591-2597
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Tidskriftsartikel (refereegranskat)abstract
- A total of 55 samples including soil, sediment, plants (cypress, reed and seepweed) and aquatic species were collected at locations around hexabromocyclododecane (HBCD) manufacturing facilities in Laizhou Bay area, East China. HBCD was determined at concentrations ranging between 0.88 and 6901 ng g(-1) dry weight (dw), 2.93-1029 ng g(-1) dw, 8.88-160241 ng g(-1) dw, and 7.09-815 ng g(-1) lipid weight (lw), respectively. Significant negative correlations (r(2) = 0.54, p = 0.006) were observed between HBCD concentrations in soils and the distance from the manufacturing facility, and the concentrations became constant when the distance was >4 km. The calculation results on the bioaccumulation factors (BAFs) suggested that HBCD may be accumulated in plants. Tissue-specific bioaccumulation of HBCD diastereoisomers was found in aquatic species. For example, in crabs the highest concentrations of HBCD (815 ng g(-1) lw for female and 446 ng g(-1) lw for male) were observed in the gill. Besides the gill, α-HBCD was more preferentially accumulated in the spermary and ovary, while β- and γ-HBCD were more accumulated in the muscle. A similar distribution was also observed in roe and muscle of goby fish.
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| 5. |
- Li, Yuanjing, et al.
(författare)
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Association of Lifelong Cognitive Reserve with Dementia and Mild Cognitive Impairment among Older Adults with Limited Formal Education : A Population-Based Cohort Study
- 2023
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Ingår i: Dementia and Geriatric Cognitive Disorders. - 1420-8008 .- 1421-9824. ; 52:4, s. 258-266
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Early-life educational attainment contributes to cognitive reserve (CR). We investigated the associations of lifelong CR with dementia and mild cognitive impairment (MCI) among older people with limited formal education. Methods: This population-based cohort study included 2,127 dementia-free participants (≥60 years; 59.4% women; 81.5% with no or elementary school) who were examined at baseline (August-December 2014) and follow-up (March-September 2018). Lifelong CR score at baseline was generated from six lifespan intellectual factors. Dementia, MCI, and their subtypes were defined according to the international criteria. Data were analyzed using Cox proportional-hazards models. Results: During the total of 8,330.6 person-years of follow-up, 101 persons were diagnosed with dementia, including 74 with Alzheimer's disease (AD) and 26 with vascular dementia (VaD). The high (vs. low) tertile of lifelong CR score was associated with multivariable-adjusted hazards ratios (95% confidence interval) of 0.28 (0.14–0.55) for dementia and 0.18 (0.07–0.48) for AD. The association between higher CR and reduced AD risk was significant in people aged 60–74 but not in those aged ≥75 years (p for interaction = 0.011). Similarly, among MCI-free people at baseline (n = 1,635), the high (vs. low) tertile of lifelong CR score was associated with multivariable-adjusted hazard ratios of 0.51 (0.38–0.69) for MCI and 0.46 (0.33–0.64) for amnestic MCI. Lifelong CR was not related to VaD or non-amnestic MCI. Discussion: High lifelong CR is associated with reduced risks of dementia and MCI, especially AD and amnestic MCI. It highlights the importance of lifelong CR in maintaining late-life cognitive health even among people with no or limited education.
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| 6. |
- Li, Yingming, et al.
(författare)
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Levels and vertical distributions of PCBs, PBDEs, and OCPs in the atmospheric boundary layer : observation from the Beijing 325-m meteorological tower
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:4, s. 1030-1035
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Tidskriftsartikel (refereegranskat)abstract
- Polyurethane foam disk passive air sampling was carried out to investigate the levels, vertical distributions, and potential sources of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in the atmospheric boundary layer of an urban site in Asia. Sampling was performed at nine heights (15, 47, 80, 120, 160, 200, 240, 280, 320 m) of the 325-m meteorological tower in Beijing, China over three 2-month periods between December 2006 and August 2007. This is the first study to report vertical variations of PBDEs in the ABL and one of only a few studies to investigate vertical distributions of persistent organic pollutants. The levels of sigma19PCBs and sigma8PBDEs were relatively low, ranging from 22 to 65 and from 2.3 to 18 pg m-3, respectively. Air concentrations of gamma-HCH were high, with values in the range of 39-103 pg m-3 in winter, 100-180 pg m-3 in spring, and 115-242 pg m-3 in summer, respectively. alpha-HCH concentrations ranged from 20 to 86 pg m-3, p,p'-DDT between 7.3 and 78 pg m-3, and HCB between 15 and 160 pg m-3. The seasonal variations of PCBs, PBDEs, and OCPs may reflect different sources for these chemicals, such as those related with regional use (gamma-HCH), volatilization/re-emission (PBDEs, PCBs, alpha-HCH), and pesticide impurities (HCB). Although the performance reference compounds (PRCs) were spiked before deployment, the sampling rates showed strong dependency on wind speeds, resulting in large variations in uptake rates in the ABL, ranging from approximately 7.0 m3 day-1 at ground level to 11 m3 day-1 at 320 m. Levels of PCBs, PBDEs, and OCPs decreased with increasing ABL height indicating the potential of Beijing as the local sources.
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| 7. |
- Li, Yingming, et al.
(författare)
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Reduction of atmospheric polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during the 2008 Beijing Olympic games
- 2011
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 45:8, s. 3304-3309
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Tidskriftsartikel (refereegranskat)abstract
- A total of 120 air samples were collected at three urban and one rural location in Beijing, China in the summers of 2007-2010, and before, during, and after the Beijing 2008 Olympic Games (BOG), in order to assess the effectiveness of long-term and short-term emission-control measures in reducing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the atmosphere. During the BOG (August, 2008), the PCDD/Fs concentrations decreased to an average value of 1150 fg m−3 (63 fg I-TEQ m−3), which was reduced by approximately 70% from the average in 2007 and by 29% from that in July 2008, before the Olympic event began. Although 2009-2010 levels of PCDD/Fs were significantly higher than 2008, the overall temporal trend was decreasing for summer months during the sampling campaign period. The apparent half-lives of atmospheric PCDD/Fs were estimated to be 3.2-5.8 years by statistically regressing the logarithm PCDD/Fs concentrations versus the number of years passed since 2006. The air concentrations of total suspended particulates (TSP) during the BOG ranged between 135 and 183 μg m−3, showing a 52% reduction from 2007 and 26% decrease from those prior to the Olympic event. No significant relationships were found between meteorological parameters (temperature, humidity, and wind speed) and PCDD/Fs or TSP during the BOG, whereas the PCDD/Fs concentrations were significantly dependent on the air quality (p < 0.05, positive against TSP and negative against visibility). This work is one of few temporal trend studies of atmospheric PCDD/Fs in mainland China, and provides unique insight into the effects of large-scale control measures in improving air quality and reducing one of the most ubiquitous and toxic organic pollutants in the environment.
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| 8. |
- Ruan, Ting, et al.
(författare)
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Presence and partitioning behavior of polyfluorinated iodine alkanes in environmental matrices around a fluorochemical manufacturing plant : another possible source for perfluorinated carboxylic acids?
- 2010
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 44:15, s. 5755-5761
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Tidskriftsartikel (refereegranskat)abstract
- The indistinct origins of some ubiquitous perfluorinated alkyl acids have attracted great attention in recent decades. In this present work, even-chained polyfluorinated iodides (PFIs), a group of volatile perfluorinated compounds (PFCs), including four perfluorinated iodine alkanes (FIAs) and three polyfluorinated telomer iodides (FTIs) were confirmed to be present in the environment. A wide concentration range was found for FIAs at 1.41 to 3.08x104 pg/L, and for FTIs at 1.39 to 1.32x103 pg/L in the ambient air collected around a fluorochemical manufacturing plant in Shandong province, northern China. Whereas for surface soils, most of these PFIs were below detection limits and only small amounts of analytes with higher carbon chain (such as perfluorododecyl iodide and 1H,1H,2H,2H-perfluorodecyl iodide, 16.6-499 pg/g) could be sporadically detected. The presence of the PFIs in different environmental matrices in the investigated area and calculated vapor pressures (0.095-20.4 Torr) verify that they can be considered as volatile organic chemicals and easily be released into the atmosphere. Together with reported degradation ability and long-range transport potential, the identification of these PFIs indicates that unintentional release during the telomer reaction process might also be another route for the formation and distribution of certain polyfluorinated alcohols, aldehydes, and carboxylic acid derivatives under oxidative conditions in the environment.
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| 9. |
- Ruan, Ting, et al.
(författare)
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Trace determination of airborne polyfluorinated iodine alkanes using multisorbent thermal desorption/gas chromatography/high resolution mass spectrometry
- 2010
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Ingår i: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1217:26, s. 4439-4447
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Tidskriftsartikel (refereegranskat)abstract
- A novel gas chromatography/high resolution mass spectrometry method coupled with multisorbent thermal desorption cartridges has been developed for the determination of volatile neutral polyfluorinated iodine alkanes (PFIs) in airborne samples. It allows, for the first time, simultaneous analysis of four mono-iodized perfluorinated alkanes, three diiodized perfluorinated alkanes and four mono-iodized polyfluorinated telomers in ambient air samples. 3.75 L air sample was passed through a sorbent tube packed with 150 mg of Tenax TA and 200mg of Carbograph 1 TD for analyte adsorption. Important factors during the analysis procedures, such as safe sampling volume, air sampling rate, analyte desorption and transfer strategies, were optimized and good thermal desorption efficiencies were obtained. The method detection limit (MDL) concentration ranged from 0.04 pg/L for 1H,1H,2H,2H-perfluorododecyl iodide to 1.2 pg/L for perfluorohexyl iodide, and instrument response of a seven-point calibration was linear in the range of 10-1000 pg. Travel spike recoveries ranged from 83% to 116%. Small variabilities of less than 36% were obtained near the MDLs and the differences between triplicates were even smaller (2.1-7.3%) at 200 pg spiked level. The method was successfully applied to analyze ambient air samples collected near a point source, and five PFIs were identified (10.8-85.0 pg/L), with none of the analytes detectable at the background site.
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| 10. |
- Shang, Hongtao, et al.
(författare)
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Bioaccumulation of PCDD/Fs, PCBs and PBDEs by earthworms in field soils of an E-waste dismantling area in China
- 2013
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 54, s. 50-58
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Tidskriftsartikel (refereegranskat)abstract
- A total of 60 paired samples of earthworm, corresponding soil and wormcast were collected to investigate the bioaccumulation tendency of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in earthworms from a typical E-waste dismantling area in east China. Significant correlations were observed for the total concentrations among different matrix types except for PCDD/Fs in soil and earthworm. The bioaccumulation tendency showed some differences among the contaminants. Calculated biota-soil accumulation factors (BSAFs) indicated that PCBs and PBDEs had higher bioaccumulation potential compared to PCDD/Fs, which was somewhat different from laboratory studies. The plot of mean BSAFs versus log Kow values for PCBs and PBDEs was well fitted by a second-order polynomial with the maximum BSAF at approximately log Kow of 6.5. While for PCDD/Fs, only a slightly decreasing trend was observed with increasing log Kow. Composition analysis indicated that tetra-, penta- and hexa-halogenated homologs had higher bioaccumulation levels, indicating that medium-halogenated congeners with log Kow around 6.5 are more easily accumulated by earthworms. Furthermore, the ratios of BDE-47/-99 and BDE-99/-100 showed some discrepancies with the technical products and other biotic species, suggesting different bioaccumulation potential of PBDEs in earthworm.
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