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- Bidleman, Terry, et al.
(författare)
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Chapter 2: Properties, sources, global fate and transport
- 2013
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Ingår i: Canadian Arctic Contaminants Assessment Report III 2013. - Ottawa : Northern Contaminants Program, Aboriginal Affairs and Northern Development Canada. - 9781100546520 ; , s. 19-146
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Bokkapitel (refereegranskat)abstract
- Part II of the second Canadian Arctic Contaminants Assessment Report (CACAR-II) began with a section on “Physicochemical Properties of Persistent Organic Pollutants”, which identified key physicochemical (pchem) properties, provided the rationale for their measurement or prediction and tabulated literature citations for chemicals that are of concern to the NCP (Bidleman et al. 2003). The section also discussed temperature dependence of pchem properties and their applications to describing partitioning in the physical environment.There is, and will continue to be, emphasis on predictive approaches to screening chemicals for persistence, bioaccumulation and toxic (PB&T)properties, as well as long-range atmospheric transport (LRAT) potential (Brown and Wania 2008, Czub et al. 2008, Fenner et al. 2005, Gouin andWania 2007, Howard and Muir 2010, Klasmeier et al. 2006, Matthies et al. 2009, Muir and Howard 2006). This has created the need for determining pchem properties of new and emerging chemicals of concern.Predicting gas exchange cycles of legacy persistent organic pollutants (POPs) and new and emerging chemicals of concern places a high demand on the accuracy of pchem properties, particularly the air/water partition coefficient, KAW. Hexachlorocyclohexanes (HCHs) in Arctic Ocean surface waters are close to air-water equilibrium, with excursions toward net volatilization or deposition that vary with location and season (Hargrave et al. 1993, Jantunen et al. 2008a, Lohmann et al. 2009, Su et al. 2006, Wong et al. 2011) while hexachlorobenzene (HCB) (Lohmann et al. 2009, Su et al. 2006, Wong et al. 2011) and some current use pesticides (CUPs) (Wong et al. 2011) are undergoing net deposition. The predicted Arctic Contamination Potential (ACP) for persistent organic chemicals is strongly influenced by ice cover due to its effect on air-water gas exchange (Meyer and Wania 2007).Many advances have taken place and numerous papers have been published since CACAR-II, which present new measurements and predictions of pchem properties. This section does not attempt to provide a comprehensive review of the field, or to compile pchem properties from the many studies. The approach taken is to highlight the reports which are most relevant to polar science, particularly in areas of improving reliability of pchem properties for POPs, improving experimental techniques and comparing predictive methods. The section ends with a discussion of polyparameter linear free energy relationships (pp-LFERs), which goes beyond partitioning descriptions based on single pchem properties by taking into account specific chemical interactions that can take place in airsurface and water-surface exchange processes. A detailed list of chemical names and nomenclature are provided in the Glossary.
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| 2. |
- Arnot, Jon A., et al.
(författare)
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Toward a Consistent Evaluative Framework for POP Risk Characterization
- 2011
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 45:1, s. 97-103
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of Annex E in the Stockholm Convention (SC) on Persistent Organic Pollutants (POPs) is to assess whether a chemical is likely, as a result of its long-range environmental transport, to lead to significant adverse human health or environmental effects, such that global action is warranted. To date, risk profiles for nominated POPs have not consistently selected assessment endpoints or completed mandated risk characterizations. An assessment endpoint hierarchy is proposed to facilitate risk characterization for the implementation of the SC. The framework is illustrated for a nominated POP, hexabromocyclododecane (HBCD), using three risk estimation methods. Based on current monitoring and toxicity data, the screening-level results indicate that humans and ecological receptors in remote regions such as the Arctic are unlikely to experience significant adverse effects (i.e., low risk) due to long-range environmental transport of HBCD. The results for birds are more uncertain than the results for fish and mammals due to the paucity of avian toxicity data. Risk characterization results for HBCD and for some listed POPs are compared to illustrate how the proposed methods can further assist decision-making and chemical management.
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| 3. |
- Gouin, Todd, et al.
(författare)
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Influence of global climate change on chemical fate and bioaccumulation : The role of multimedia models
- 2013
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 32:1, s. 20-31
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Tidskriftsartikel (refereegranskat)abstract
- Multimedia environmental fate models are valuable tools for investigating potential changes associated with global climate change, particularly because thermodynamic forcing on partitioning behavior as well as diffusive and nondiffusive exchange processes are implicitly considered. Similarly, food-web bioaccumulation models are capable of integrating the net effect of changes associated with factors such as temperature, growth rates, feeding preferences, and partitioning behavior on bioaccumulation potential. For the climate change scenarios considered in the present study, such tools indicate that alterations to exposure concentrations are typically within a factor of 2 of the baseline output. Based on an appreciation for the uncertainty in model parameters and baseline output, the authors recommend caution when interpreting or speculating on the relative importance of global climate change with respect to how changes caused by it will influence chemical fate and bioavailability.
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| 4. |
- Wang, Thomas J, et al.
(författare)
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Common genetic determinants of vitamin D insufficiency: a genome-wide association study.
- 2010
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Ingår i: Lancet. - 1474-547X. ; 376:9736, s. 180-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Vitamin D is crucial for maintenance of musculoskeletal health, and might also have a role in extraskeletal tissues. Determinants of circulating 25-hydroxyvitamin D concentrations include sun exposure and diet, but high heritability suggests that genetic factors could also play a part. We aimed to identify common genetic variants affecting vitamin D concentrations and risk of insufficiency. METHODS: We undertook a genome-wide association study of 25-hydroxyvitamin D concentrations in 33 996 individuals of European descent from 15 cohorts. Five epidemiological cohorts were designated as discovery cohorts (n=16 125), five as in-silico replication cohorts (n=9367), and five as de-novo replication cohorts (n=8504). 25-hydroxyvitamin D concentrations were measured by radioimmunoassay, chemiluminescent assay, ELISA, or mass spectrometry. Vitamin D insufficiency was defined as concentrations lower than 75 nmol/L or 50 nmol/L. We combined results of genome-wide analyses across cohorts using Z-score-weighted meta-analysis. Genotype scores were constructed for confirmed variants. FINDINGS: Variants at three loci reached genome-wide significance in discovery cohorts for association with 25-hydroxyvitamin D concentrations, and were confirmed in replication cohorts: 4p12 (overall p=1.9x10(-109) for rs2282679, in GC); 11q12 (p=2.1x10(-27) for rs12785878, near DHCR7); and 11p15 (p=3.3x10(-20) for rs10741657, near CYP2R1). Variants at an additional locus (20q13, CYP24A1) were genome-wide significant in the pooled sample (p=6.0x10(-10) for rs6013897). Participants with a genotype score (combining the three confirmed variants) in the highest quartile were at increased risk of having 25-hydroxyvitamin D concentrations lower than 75 nmol/L (OR 2.47, 95% CI 2.20-2.78, p=2.3x10(-48)) or lower than 50 nmol/L (1.92, 1.70-2.16, p=1.0x10(-26)) compared with those in the lowest quartile. INTERPRETATION: Variants near genes involved in cholesterol synthesis, hydroxylation, and vitamin D transport affect vitamin D status. Genetic variation at these loci identifies individuals who have substantially raised risk of vitamin D insufficiency. FUNDING: Full funding sources listed at end of paper (see Acknowledgments).
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