| 31. |
- Wang, Pu, et al.
(författare)
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Altitude dependence of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in surface soil from Tibetan Plateau, China
- 2009
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 76:11, s. 1498-1504
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Tidskriftsartikel (refereegranskat)abstract
- Remote mountain areas besides high latitude regions are beginning to receive increased attention in studying the transport and behavior of persistent organic pollutants (POPs). In the present work, surface soil samples were collected from the Tibetan Plateau, the highest plateau in the world which includes the northern slope of Mt. Qomolangma, to investigate the levels and trends of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) along the altitudinal gradient. The average PCB and PBDE concentrations were 185.6 ng kg-1 dry weight (dw) (range 47.1-422.6 ng kg-1 dw) and 11.1 ng kg-1 dw (range 4.3-34.9 ng kg-1 dw), respectively. Regression analysis between the log-transformed TOC-normalized concentrations and the altitudes of the sampling sites showed two opposite trends with regard to altitude dependence: negative relationship with altitude below about 4500 m followed by a positive altitude dependence above this point. Considering minimum anthropogenic activities and very sparse precipitation in the north of Himalayas, the trends above 4500 m imply that the significant altitude dependence of these two groups of POPs were irrespective of pollution sources, but could be predicted by the global distillation effect involving cold condensation in high altitude mountain areas. Increasing levels of heavier congeners were found in higher altitude sites, although the lighter congeners were the main contributors to the total amount, suggesting that less volatile congeners seem to become enriched easier than those more volatile at higher altitudes in this region.
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| 32. |
- Wang, Pu, et al.
(författare)
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Evaluation of Soxhlet extraction, accelerated solvent extraction and microwave-assisted extraction for the determination of polychlorinated biphenyls and polybrominated diphenyl ethers in soil and fish samples
- 2010
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Ingår i: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 663:1, s. 43-48
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Tidskriftsartikel (refereegranskat)abstract
- Three commonly applied extraction techniques for persistent organic chemicals, Soxhlet extraction (SE), accelerated solvent extraction (ASE) and microwave-assisted extraction (MAE), were applied on soil and fish samples in order to evaluate their performances. For both PCBs and PBDEs, the two more recent developed techniques (ASE and MAE) were in general capable of producing comparable extraction results as the classical SE, and even higher extraction recoveries were obtained for some PCB congeners with large octanol-water partitioning coefficients (K(ow)). This relatively uniform extraction results from ASE and MAE indicated that elevated temperature and pressure are favorable to the efficient extraction of PCBs from the solid matrices. For PBDEs, difference between the results from MAE and ASE (or SE) suggests that the MAE extraction condition needs to be carefully optimized according to the characteristics of the matrix and analyte to avoid degradation of higher brominated BDE congeners and improve the extraction yields.
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| 33. |
- Wang, Sophia S., et al.
(författare)
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HLA Class I and II Diversity Contributes to the Etiologic Heterogeneity of Non-Hodgkin Lymphoma Subtypes
- 2018
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 78:14, s. 4086-4096
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Tidskriftsartikel (refereegranskat)abstract
- A growing number of loci within the human leukocyte antigen (HLA) region have been implicated in non-Hodgkin lymphoma (NHL) etiology. Here, we test a complementary hypothesis of "heterozygote advantage" regarding the role of HLA and NHL, whereby HLA diversity is beneficial and homozygous HLA loci are associated with increased disease risk. HLA alleles at class I and II loci were imputed from genome-wide association studies (GWAS) using SNP2HLA for 3,617 diffuse large B-cell lymphomas (DLBCL), 2,686 follicular lymphomas (FL), 2,878 chronic lymphocytic leukemia/small lymphocytic lymphomas (CLL/SLL), 741 marginal zone lymphomas (MZL), and 8,753 controls of European descent. Both DLBCL and MZL risk were elevated with homozygosity at class I HLA-B and -C loci (OR DLBCL = 1.31, 95% CI = 1.06-1.60; OR MZL = 1.45, 95% CI = 1.12-1.89) and class II HLA-DRB1 locus (OR DLBCL = 2.10, 95% CI = 1.24-3.55; OR MZL = 2.10, 95% CI = 0.99-4.45). Increased FL risk was observed with the overall increase in number of homozygous HLA class II loci (P trend < 0.0001, FDR = 0.0005). These results support a role for HLA zygosity in NHL etiology and suggests that distinct immune pathways may underly the etiology of the different NHL subtypes. Significance: HLA gene diversity reduces risk for non-Hodgkin lymphoma.
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| 34. |
- Wang, Thanh, 1979-, et al.
(författare)
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Characteristic accumulation and soil penetration of polychlorinated biphenyls and polybrominated diphenyl ethers in wastewater irrigated farmlands
- 2010
-
Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 81:8, s. 1045-1051
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Tidskriftsartikel (refereegranskat)abstract
- The impact of wastewater irrigation on the distribution of two groups of persistent organic pollutants (POPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), in farm soil was investigated in this study. The concentrations of total analyzed PCBs were in the range 256-2140 pg g-1 on dry weight basis in surface soils. There was a higher accumulation of PCBs in farms irrigated by wastewater, with decachlorobiphenyl (CB-209) as the predominant congener. The spatial distributions of PBDEs were similar although not as obvious as that of PCBs, and BDE-209 was the predominant congener at 2040-496000 pg g-1dw, accounting for >96% of the total analyzed PBDEs. However, no significant correlations could be found between PCB and PBDE concentrations in the topsoil samples, and also with soil organic content between the different sites. On the other hand, soil vertical profiles showed significant relationship with soil organic content in cores taken from farms irrigated with wastewater. The vertical distribution was quite uniform at the topsoil, corresponding to the plowed layer, and decreased thereafter exponentially. Furthermore, the soil vertical distribution was found to be congener specific for PCBs, where less chlorinated congeners were able to penetrate deeper into the soil while heavier congeners were more restricted in their movement. This fractionation process was however not found for PBDEs. Also, the prevalence and high relative concentrations of CB-11 and CB-209 suggests that these PCB congeners should more often be included in routine environmental analysis in order to identifying unusual contamination sources.
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| 35. |
- Wang, Yawei, et al.
(författare)
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Assessment of polychlorinated biphenyls and polybrominated diphenyl ethers in Tibetan butter.
- 2010
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 78:6, s. 772-777
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Tidskriftsartikel (refereegranskat)abstract
- The Tibetan plateau is considered a potential cold trap for persistent organic pollutants (POPs) and plays an important role in the global long-range transport of these compounds. This present work surveyed the concentrations of polychlorinated biphenyl (PCBs) and polybrominated diphenyl ethers (PBDEs) in Tibetan butter samples collected from different prefectures in Tibet autonomous region (TAR). summation operator(25)PCB concentrations ranged from 137 to 2518 pg g(-1) with a mean value 519 pg g(-1), which were far lower than those in the butter from other regions in the world. The highest level was found in butter from Sichuan province, which is located to the east of the Tibetan plateau and the lowest value was in samples from southeast TAR. The average concentration of summation Sigma(12)PBDE was 125 pg g(-1). The sample with highest and lowest summation Sigma(12)PBDE concentration (955 and 18.0 pg g(-1)) was from the south and southeast part of the plateau, respectively. Back trajectory model implied that the sources of these two groups of POPs were by atmospheric deposition in south, whereas the western plateau was mainly influenced by the tropical monsoon from south Asia. Air currents from Sichuan and Gansu province are further responsible for the atmospheric transport of PCBs and PBDEs to the eastern and northern side of the plateau. Local air concentrations of summation Sigma(5)PCBs predicted using air-milk transfer factor were at the lower end of published global levels.
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| 36. |
- Wang, Yawei, et al.
(författare)
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Effect of municipal sewage treatment plant effluent on bioaccumulation of polychlorinated biphenyls and polybrominated diphenyl ethers in the recipient water
- 2007
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 41:17, s. 6026-6032
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Tidskriftsartikel (refereegranskat)abstract
- Water, sediment, and aquatic species including plankton, fish, and turtles were collected from a small lake in Beijing, which receives effluent discharged from a large sewage treatment plant (STP). The samples were examined to investigate polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) releases from a STP and their distributions in the lake. The accumulations of ∑12PBDEs and BDE-209 in the sediment were 62.3 and 1150 ng/cm2, respectively, while that of ∑PCBs was 99.3 ng/cm2. BDE-209 was detected in more than 50% of the aquatic species. A strong linear correlation (R2 = 0.92) was found between ∑12PBDEs and ∑PCBs levels in aquatic species but not in sediments. The different PBDE congener profiles in sediments and biota samples suggest metabolic debromination in the sampled fish. Bioaccumulations of PBDEs and PCBs were found in aquatic species.The logarithm bioaccumulation factor (BAF) decreases with the number of bromines in PBDEs molecules, while the log BAF versus the number of chlorines in PCBs appears to be parabolic. Biomagnifications of these compounds were not obvious in the food web by analysis of the relationship between ∑12PBDEs or ∑PCBs levels and the trophic level of aquatic biota species.
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| 37. |
- Wang, Yawei, et al.
(författare)
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Selection of bioindicators of polybrominated diphenyl ethers, polychlorinated biphenyls, and organochlorine pesticides in mollusks in the Chinese Bohai Sea
- 2008
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 42:19, s. 7159-7165
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Tidskriftsartikel (refereegranskat)abstract
- Mollusks, including bivalve and gastropod samples, were collected in the summer of 2006 and 2007 to evaluate the spatial patterns of organochlorine pesticides (OCPs), polychlorinated biphenyl (PCBs), and polybrominated biphenyl ethers (PBDEs) in the coastal water of the Chinese Bohai Sea. Seven species of mollusks, including Rapana venosa (Rap), Neverita didyma (Nev), Scapharca subcrenata (Sca), Mytilus edulis (Blue mussel, Myt), Amusium (Amu), Meretix meretrix (Mer), and Crassostrea talienwhanensis (Oyster, Ost) were investigated to select appropriate bioindicators. Compared with other species, Ost and Myt possess higher lipid contents and have higher concentrations of OCPs and PBDEs. Multivariate linear regression analysis revealed that the most influential factor on the contaminant concentrations in mollusks is the trophic level (TL), followed by the lipid contents. Concentrations of OCPs, PCBs, and PBDEs correlated negatively with the TL of the selected mollusks. Results of principal component and correlation analyses suggest that Ost and Myt can be used as potential bioindicators of pollution by OCPs, PCBs, and PBDEs of the Chinese Bohai Sea.
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| 38. |
- Yang, Ruiqiang, et al.
(författare)
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Organochlorine pesticides and PCBs in fish from lakes of the Tibetan Plateau and the implications
- 2010
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 158:6, s. 2310-6
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Tidskriftsartikel (refereegranskat)abstract
- High mountains may play significant roles in the global transport of persistent organic pollutants (POPs). This work aims to investigate the levels, patterns and distribution of semi-volatile organochlorine pollutants and to improve the understanding of the long-range atmospheric transport and fate of contaminants on the Tibetan Plateau. A total of 60 fish samples were collected from eight lakes located between 2813 and 4718 m above sea level across the Plateau. Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) including dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were measured in fish muscle. The results showed that concentrations of DDT, HCH and HCB were comparable to or lower than those found in remote mountains of Europe, Canada and US, while PCB concentrations in fish were, on average, about 4-150 times lower on Tibet than at other mountain areas. The transport and fate of contaminants in the Plateau are significantly influenced by the unique climatological and meteorological conditions, particularly by the summer Indian monsoon and winter westerly jet stream.
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| 39. |
- Yu, Miao, et al.
(författare)
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Structure prediction of methyoxy-polybrominated diphenyl ethers (MeO-PBDEs) through GC-MS analysis of their corresponding PBDEs
- 2016
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Ingår i: Talanta. - Amsterdam, Netherlands : Elsevier. - 0039-9140 .- 1873-3573. ; 152, s. 9-14
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Tidskriftsartikel (refereegranskat)abstract
- It is hard to quantify the trace pollutants in the environment without the corresponding reference standards. Structure identifications of unknown organic pollutants are thus of great importance in environmental analysis. As for polybrominated diphenyl ethers (PBDE) with one substituent of methoxyl group, there are 837 congeners, but only 32 standards are commercially available. In this work, an effective method based on gas chromatography coupled with mass spectrometry (GC-MS) was proposed to predict the potential structures of methoxylated polybrominated diphenyl ethers (MeO-PBDEs). The mass fragmentation pattern using SIM mode not only provided the useful information on the substitution position of methoxyl group, the number of Br atoms, but also guaranteed the high sensitivity for trace analysis. Br distribution patterns of the unknown MeO-PBDEs were revealed by a linear regression model with dummy variables which described the retention time relationship between MeO-PBDEs and the corresponding PBDEs on different types of GC columns. This method was successfully used to identify three new MeO-PBDEs metabolites of BDE-28 as 4-MeO-BDE-22, 4'-MeO-BDE-25 and 4-MeO-BDE-31 in the pumpkins. Therefore, the newly developed structure prediction model based on GC-MS behavior is helpful in the evaluation of unknown PBDE metabolites in the environment.
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| 40. |
- Yuan, Bo, et al.
(författare)
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Short chain chlorinated paraffins in mollusks from coastal waters in the Chinese Bohai Sea
- 2012
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46:12, s. 6489-6496
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Tidskriftsartikel (refereegranskat)abstract
- As an extremely complex group of persistent organic pollutants (POPs) candidates in the Stockholm Convention, short chain chlorinated paraffins (SCCPs) have been of extensive concern in recent years. In this study, nine bivalve and two gastropod species were collected in 2009 to evaluate the spatial distributions and potential factors influencing the bioaccumulation of SCCPs in mollusks in the Chinese Bohai Sea. The concentrations of ∑ SCCPs in the mollusks were in the range 64.9-5510 ng/g (dry weight) with an average chlorine content of 61.1%. C(10) and C(11) were the predominant homologue groups of SCCPs, which accounted for about 29.7% and 34.9% of ∑ SCCPs, respectively. Six and seven chlorinated substituents were the main congener groups. Mya arenaria (Mya), Mactra veneriformis (Mac), and Crassostrea talienwhanensis (Oyster, Ost) had higher average concentrations of SCCPs than other species, implying that these bivalves could be used as sentinels to indicate SCCPs contamination in this coastal region. A significant positive linear relationship was found between SCCP concentrations and lipid content of the mollusks, whereas the lipid-normalized SCCP concentrations were negatively linear-related to the trophic levels (TL), which implied that SCCPs did not show biomagnification in mollusks in this region.
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