Journal ArticleDOI
OH Radical Reactions: The Major Removal Pathway for Polychlorinated Biphenyls from the Atmosphere
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In this article, a simple model for the vertical concentration gradient of PCBs in the troposphere was developed and used to calculate the total global loss rate (8300 t yr-1) of polychlorinated biphenyls from the atmosphere due to removal by OH.Abstract:
Polychlorinated biphenyls (PCBs) are transported through the environment primarily in the atmosphere and may undergo chemical reactions, particularly with the OH radical, while in the vapor phase. Rate constants for the gas-phase reaction of 14 PCB congeners with the OH radical over the temperature range of 323−363 K were measured. The calculated temperature dependences of the reactions were used to estimate OH−PCB reaction rate constants at 298 K; see Table 4. These 298 K rate constants agree well with literature rate constants for PCBs containing zero to two chlorines and with OH−PCB reaction rate constants estimated from a structure−activity method. Calculated atmospheric lifetimes of PCBs due to OH-initiated reactions varied from 2 days for biphenyl to 34 days for a pentachlorobiphenyl. A simple model for the vertical concentration gradient of PCBs in the troposphere was developed and used to calculate the total global loss rate (8300 t yr-1) of PCBs from the atmosphere due to removal by OH. This path...read more
Citations
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Toxicological profile for polychlorinated biphenyls (PCBs)
Obaid Faroon,James N. Olson +1 more
TL;DR: A toxicological profile for PCBs, Draft for Public Comment, was released in December 1998 as discussed by the authors, which supercedes any previously released draft or final profile, but no less than once every three years.
Journal ArticleDOI
Degradation half-life times of PCDDs, PCDFs and PCBs for environmental fate modeling.
TL;DR: Literature search of the knowledge on the degradation of persistent organic pollutants (POPs) in environmental compartments air, water, soil and sediment was done in purpose to find properties of POPs of interest for modeling.
Journal ArticleDOI
Temporal and spatial variabilities of atmospheric polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and polycyclic aromatic hydrocarbons (PAHs) in the Canadian Arctic: Results from a decade of monitoring
Hayley Hung,Pierrette Blanchard,Crispin J. Halsall,T. F. Bidleman,Gary A. Stern,P. Fellin,Derek C. G. Muir,Leonard A. Barrie,Liisa M. Jantunen,Paul A. Helm,Jianmin Ma,Alexei Konoplev +11 more
TL;DR: The Northern Contaminants Program (NCP) baseline monitoring project was established in 1992 to monitor for persistent organic pollutants (POPs) in Arctic air and results obtained in the past 5 years are summarized.
Journal ArticleDOI
Evaluating environmental persistence
TL;DR: In this article, it is shown that the overall environmental half-life or persistence in a multimedia environment is also a function of the mode of entry of the chemical and its partitioning properties.
Journal ArticleDOI
Activation of persulfate with vanadium species for PCBs degradation: A mechanistic study
TL;DR: In this article, the activation of persulfate (PS) with vanadium (V) species for PCBs degradation was investigated for the first time, and it was found that PS exhibited high catalytic activity toward PS decomposition for PCB28 degradation.
References
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Journal ArticleDOI
Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and related compounds: environmental and mechanistic considerations which support the development of toxic equivalency factors (TEFs).
TL;DR: The most toxic halogenated aromatic is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and based on in vivo and in vitro studies the relative toxicities have been determined relative to TCDD (i.e., toxic equivalents).
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Protein Folding Intermediates: Native-State Hydrogen Exchange
TL;DR: The partially unfolded forms detected by hydrogen exchange appear to represent the major intermediates in the reversible, dynamic unfolding reactions that occur even at native conditions and thus may define the major pathway for cytochrome c folding.
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Atmospheric Trends and Lifetime of CH3CCI3 and Global OH Concentrations.
Ronald G. Prinn,Ray F. Weiss,Benjamin R. Miller,Jian Yu Huang,F. N. Alyea,Derek M. Cunnold,Paul J. Fraser,Dana E. Hartley,Peter Simmonds +8 more
TL;DR: The lifetime of CH3CCI3 in the total atmosphere is 4.8 � 0.3 years, which is substantially lower than previously estimated and the deduced hydroxyl radical concentration shows little change from 1978 to 1994.
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The effect of intrauterine PCB exposure on visual recognition memory.
TL;DR: The relation between prenatal exposure and visual recognition was not mediated by the neonatal deficits, suggesting that intrauterine PCB exposure may have a delayed effect on central nervous system (CNS) functioning.
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Large Lakes of the World
TL;DR: An inventory of the distribution, origin, and morphometry of the world's large lakes has been undertaken by as mentioned in this paper, which shows that the large lakes occupy a surface area of 1.456,000 km 2 and they have an estimated volume of 202.000 km 3.