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1.
Sci Total Environ ; 775: 145109, 2021 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-33631575

RESUMEN

The long-term time trends of atmospheric pollutants at eight Arctic monitoring stations are reported. The work was conducted under the Arctic Monitoring and Assessment Programme (AMAP) of the Arctic Council. The monitoring stations were: Alert, Canada; Zeppelin, Svalbard; Stórhöfði, Iceland; Pallas, Finland; Andøya, Norway; Villum Research Station, Greenland; Tiksi and Amderma, Russia. Persistent organic pollutants (POPs) such as α- and γ-hexachlorocyclohexane (HCH), polychlorinated biphenyls (PCBs), α-endosulfan, chlordane, dichlorodiphenyltrichloroethane (DDT) and polybrominated diphenyl ethers (PBDEs) showed declining trends in air at all stations. However, hexachlorobenzene (HCB), one of the initial twelve POPs listed in the Stockholm Convention in 2004, showed either increasing or non-changing trends at the stations. Many POPs demonstrated seasonality but the patterns were not consistent among the chemicals and stations. Some chemicals showed winter minimum and summer maximum concentrations at one station but not another, and vice versa. The ratios of chlordane isomers and DDT species showed that they were aged residues. Time trends of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were showing decreasing concentrations at Alert, Zeppelin and Andøya. The Chemicals of Emerging Arctic Concern (CEAC) were either showing stable or increasing trends. These include methoxychlor, perfluorohexane sulfonic acid (PFHxS), 6:2 fluorotelomer alcohol, and C9-C11 perfluorocarboxylic acids (PFCAs). We have demonstrated the importance of monitoring CEAC before they are being regulated because model calculations to predict their transport mechanisms and fate cannot be made due to the lack of emission inventories. We should maintain long-term monitoring programmes with consistent data quality in order to evaluate the effectiveness of chemical control efforts taken by countries worldwide.

2.
Chemosphere ; 193: 343-350, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29149710

RESUMEN

The large surface area of Lake Victoria (about 68,800 km2) makes it vulnerable to high atmospheric deposition of chemical pollutants. We present measurements of polychlorinated biphenyls (PCBs) from the lake's atmospheric environment. High volume air (24 h) samples were collected within the northern Lake Victoria watershed in Uganda over two periods; 1999-2004 [at Kakira (KAK) and Entebbe (EBB)] and 2008-2010 (at EBB only). Precipitation samples were also collected monthly during the 2008-2010 period at EBB. Analysis for PCBs was done using GC-µECD in a dual column approach. The ranges of ΣPCB concentrations in the KAK air samples were 154-462 pg m-3 (KAK 1999-2000), 26.7-226 pg m-3 (KAK 2003-2004), 27.0-186 pg m-3 (EBB 2003), 46.8-174 pg m-3 (EBB 2004), 19.2-128 pg m-3 (EBB 2008), 45.8-237 pg m-3 (EBB 2009) and 65.6-244 pg m-3 (EBB 2010). The di-, tri-, tetra- and penta-PCBs were predominant in air sample sets while the tetra- and penta-PCBs were predominant in precipitation samples. The mean flux of ΣPCBs in the precipitation samples was 26.9 ng m-2 (range of 14.8-41.5 and median of 27.5). Concentrations at EBB were lower than those reported elsewhere for urban sites in the East and Central African region. Multivariate analysis and analysis of air mass movements suggested influence of combustion sources on the PCB profiles from the region, especially, from the major East African urbanized regions.


Asunto(s)
Movimientos del Aire , Contaminantes Atmosféricos/análisis , Lagos/química , Bifenilos Policlorados/análisis , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente/métodos , Prevalencia , Uganda
4.
Environ Sci Technol ; 50(14): 7409-15, 2016 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-27309668

RESUMEN

Fourteen organophosphate esters (OPEs) were measured in the filter fraction of 117 active air samples from yearly ship-based sampling campaigns (2007-2013) and two land-based stations in the Canadian Arctic, to assess trends and long-range transport potential of OPEs. Four OPEs were detected in up to 97% of the samples, seven in 50% or less of the samples, and three were not detected. Median concentrations of ∑OPEs were 237 and 50 pg m(-3) for ship- and land-based samples, respectively. Individual median concentrations ranged from below detection to 119 pg m(-3) for ethanol, 2-chloro-, phosphate (3:1) (TCEP). High concentrations of up to 2340 pg m(-3) were observed for Tri-n-butyl phosphate (TnBP) at a land-based sampling location in Resolute Bay from 2012, whereas it was only detected in one ship-based sample at a concentration below 100 pg m(-3). Concentrations of halogenated OPEs seemed to be driven by river discharge from the Nelson and Churchill Rivers (Manitoba) and Churchill River and Lake Melville (Newfoundland and Labrador). In contrast, nonhalogenated OPE concentrations appeared to have diffuse sources or local sources close to the land-based sampling stations. Triphenyl phosphate (TPhP) showed an apparent temporal trend with a doubling-time of 11 months (p = 0.044). The results emphasize the increasing relevance of halogenated and nonhalogenated OPEs as contaminants in the Arctic.


Asunto(s)
Monitoreo del Ambiente , Ésteres , Canadá , Organofosfatos , Ríos
5.
Sci Total Environ ; 543(Pt A): 9-18, 2016 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-26575633

RESUMEN

The Lake Victoria watershed has extensive agricultural activity with a long history of pesticide use but there is limited information on historical use or on environmental levels. To address this data gap, high volume air samples were collected from two sites close to the northern shore of Lake Victoria; Kakira (KAK) and Entebbe (EBB). The samples, to be analyzed for pesticides, were collected over various periods between 1999 and 2004 inclusive (KAK 1999-2000, KAK 2003-2004, EBB 2003 and EBB 2004 sample sets) and from 2008 to 2010 inclusive (EBB 2008, EBB 2009 and EBB 2010 sample sets). The latter sample sets (which also included precipitation samples) were also analyzed for currently used pesticides (CUPs) including chlorpyrifos, chlorthalonil, metribuzin, trifluralin, malathion and dacthal. Chlorpyrifos was the predominant CUP in air samples with average concentrations of 93.5, 26.1 and 3.54 ng m(-3) for the EBB 2008, 2009, 2010 sample sets, respectively. Average concentrations of total endosulfan (ΣEndo), total DDT related compounds (ΣDDTs) and hexachlorocyclohexanes (ΣHCHs) ranged from 12.3-282, 22.8-130 and 3.72-81.8 pg m(-3), respectively, for all the sample sets. Atmospheric prevalence of residues of persistent organic pollutants (POPs) increased with fresh emissions of endosulfan, DDT and lindane. Hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and dieldrin were also detected in air samples. Transformation products, pentachloroanisole, 3,4,5-trichloroveratrole and 3,4,5,6-tetrachloroveratrole, were also detected. The five most prevalent compounds in the precipitation samples were in the order chlorpyrifos>chlorothalonil>ΣEndo>ΣDDTs>ΣHCHs with average fluxes of 1123, 396, 130, 41.7 and 41.3 ng m(-2)sample(-1), respectively. PeCB exceeded HCB in precipitation samples. The reverse was true for air samples. Backward air trajectories suggested transboundary and local emission sources of the analytes. The results underscore the need for a concerted regional vigilance in management of chemicals.


Asunto(s)
Contaminantes Atmosféricos/análisis , Atmósfera/química , Monitoreo del Ambiente , Plaguicidas/análisis , África Oriental , Contaminación del Aire/estadística & datos numéricos , Clorobencenos/análisis , Cloropirifos/análisis , Endosulfano/análisis , Hexaclorobenceno/análisis , Hexaclorociclohexano , Lagos , Trifluralina/análisis
6.
Environ Sci Technol ; 49(9): 5584-92, 2015 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-25844542

RESUMEN

Polycyclic aromatic hydrocarbon (PAH) measurements were conducted by Wood Buffalo Environmental Association (WBEA) at four community ambient Air quality Monitoring Stations (AMS) in the Athabasca Oil Sands Region (AOSR) in Northeastern Alberta, Canada. The 2012 and 2013 mean concentrations of a subset of the 22 PAH species were 9.5, 8.4, 8.8, and 32 ng m(-3) at AMS 1 (Fort McKay), AMS 6 (residential Fort McMurray), AMS 7 (downtown Fort McMurray), and AMS 14 (Anzac), respectively. The average PAH concentrations in Fort McKay and Fort McMurray were in the range of rural and semirural areas, but peak values reflect an industrial emission influence. At these stations, PAHs were generally associated with NO, NO2, PM2.5, and SO2, indicating the emissions were from the combustion sources such as industrial stacks, vehicles, residential heating, and forest fires, whereas the PAH concentrations at AMS 14 (∼35 km south of Fort McMurray) were more characteristic of urban areas with a unique pattern: eight of the lower molecular weight PAHs exhibited strong seasonality with higher levels during the warmer months. Enthalpies calculated from Clausius-Clapeyron plots for these eight PAHs suggest that atmospheric emissions were dominated by temperature-dependent processes such as volatilization at warm temperatures. These findings point to the potential importance of localized water-air and/or surface-air transfer on observed PAH concentrations in air.


Asunto(s)
Contaminantes Atmosféricos/análisis , Yacimiento de Petróleo y Gas , Hidrocarburos Policíclicos Aromáticos/análisis , Suelo/química , Alberta , Monitoreo del Ambiente , Incendios , Bosques , Tamaño de la Partícula , Material Particulado/análisis , Comunicaciones por Satélite , Estadísticas no Paramétricas , Temperatura , Factores de Tiempo , Emisiones de Vehículos/análisis , Volatilización
7.
Environ Sci Technol ; 48(3): 1458-66, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24400732

RESUMEN

High volume air and precipitation samples were collected close to the shore of Lake Victoria at Entebbe, Uganda, between October 2008 and July 2010 inclusive. Polybrominated diphenyl ethers (PBDEs) and alternative flame retardants (AFRs) were analyzed by GC-MS. BDEs 47, 99, and 209 were the predominant PBDEs with mean concentrations (in air) of 9.84, 4.38, 8.27 pg m(-3) and mean fluxes in precipitation of 3.40, 6.23, and 7.82 ng m(-2) sample(-1), respectively. 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and hexabromocyclododecane (HBCDD), anti- and syn-Dechlorane plus were detected at levels comparable with those of PBDEs. Both PBDEs and AFRs in air generally increased from 2008 to 2010. Elevated PBDE concentrations in air were associated with slow moving low altitude air masses from the region immediately adjacent to the lake, while low concentrations were mostly associated with fast moving westerly and southwesterly air masses. Analysis of the octa- and nona-BDE profiles suggested photolysis and pyrolytic debromination of BDE-209 in the air samples. The highly halogenated and most abundant PBDEs and AFRs in air also predominated in precipitation samples. This is the first study to report flame retardants in high volume air samples and precipitation in Equatorial Africa.


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Retardadores de Llama/análisis , Éteres Difenilos Halogenados/análisis , Lagos , Lluvia/química , Contaminantes Químicos del Agua/análisis , Bromobencenos/análisis , Hidrocarburos Bromados/análisis , Uganda
8.
Environ Sci Technol ; 46(21): 11524-31, 2012 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-23020709

RESUMEN

In the first study of its kind in Africa, PAHs were measured in high volume (24 h) air samples collected from two sampling stations, at Kakira and Entebbe (KAK and EBB, respectively) within the Lake Victoria watershed in Uganda, to assess source contributions and generate a baseline reference data set for future studies in the East African region. Sampling was conducted over two periods [2000-2004 (KAK and EBB1) and 2008-2010 (EBB2)]. The samples were extracted by accelerated solvent extraction and analyzed for 30 PAHs by GC-MS. The mean total PAH concentrations (ng/m(3)) were found to be 74.3 (range; 19.3-311, N = 39) for KAK, 56.8 (range; 13.3-126, N = 22) for EBB1 and 33.1 (range; 4.91-108, N = 56) for EBB2. The 3-ringed PAHs were the most predominant group with mean concentrations of 35.9 ng/m(3)(EBB1), 30.5 ng/m(3)(KAK) and 23.2 ng/m(3)(EBB2). Naphthalene had an exceptionally high mean concentration (21.9 ng/m(3)) for KAK compared to 0.44 and 0.39 ng/m(3) in EBB1 and EBB2 respectively, likely due to intensive agricultural operations nearby KAK. Principal component and diagnostic ratio analyses showed that the measured levels of PAHs were associated with mixed sources, combustion of petroleum, and biomass being the major sources.


Asunto(s)
Contaminantes Atmosféricos/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , África Oriental , Monitoreo del Ambiente , Lagos , Abastecimiento de Agua
9.
J Environ Monit ; 13(11): 3111-8, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21997219

RESUMEN

Initiated in 1992, air monitoring of organic pollutants in the Canadian Arctic provided spatial and temporal trends in support of Canada's participation in the Stockholm Convention of Persistent Organic Pollutants. The specific analytical laboratory charged with this task was changed in 2002 while field sampling protocols remained unchanged. Three rounds of intensive comparison studies were conducted in 2004, 2005, and 2008 to assess data comparability between the two laboratories. Analysis was compared for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in standards, blind samples of mixed standards and extracts of real air samples. Good measurement accuracy was achieved for both laboratories when standards were analyzed. Variation of measurement accuracy over time was found for some OCPs and PCBs in standards on a random and non-systematic manner. Relatively low accuracy in analyzing blind samples was likely related to the process of sample purification. Inter-laboratory measurement differences for standards (<30%) and samples (<70%) were generally less than or comparable to those reported in a previous inter-laboratory study with 21 participating laboratories. Regression analysis showed inconsistent data comparability between the two laboratories during the initial stages of the study. These inter-laboratory differences can complicate abilities to discern long-term trends of pollutants in a given sampling site. It is advisable to maintain long-term measurements with minimal changes in sample analysis.


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/normas , Hidrocarburos Clorados/análisis , Laboratorios/normas , Plaguicidas/análisis , Bifenilos Policlorados/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminación del Aire/análisis , Regiones Árticas , Sesgo , Canadá , Cromatografía de Gases y Espectrometría de Masas , Ensayos de Aptitud de Laboratorios , Modelos Lineales
10.
Tidsskr Nor Laegeforen ; 128(13): 1508-11, 2008 Jun 26.
Artículo en Noruego | MEDLINE | ID: mdl-18587456

RESUMEN

BACKGROUND: The annual Quart Rock Festival (1991-2007) was the largest rock festival in Norway. During festivals in 2004-06, a daily average of 3 000 personnel, guests and artists, and 10,000 visitors, 13,000 people, were present daily. The festival had a medical care organization recruited from primary care personnel. The team consisted of one general practitioner, one physiotherapist, two nurses from the municipality outpatient service, and lay personnel trained in first aid. MATERIAL AND METHODS: We recorded all patient contacts at the festival in 2004, 2005, and 2006 in order to describe injuries requiring medical attention and the need for referrals. RESULTS: The total number of festival participants, including personnel, was 208,000 during the registration period. Of totally 1,349 patient contacts, 254 required consultation with a nurse and 191 with the attending physician. There were no deaths, cardiac or respiratory arrests or serious penetrating trauma. 33 contacts were related to intoxication: 24 due to alcohol, five to illegal drugs and four to unknown substances. Violence-related injuries were the cause of 18 contacts, of which none were serious. 49 patients were referred for follow-up, mostly to the municipality outpatient service or their own physician, and five patients were admitted to hospital. The transport-to-hospital-ratio was 0.24 per 10,000 participants. INTERPRETATION: The results are similar to those in studies of rock festivals in other countries. The need for referrals was equal to or lower than in other studies. This indicates that the primary care-based medical organization at the Quart Festival was adequate.


Asunto(s)
Servicios Médicos de Urgencia , Vacaciones y Feriados , Adulto , Niño , Aglomeración , Servicios Médicos de Urgencia/estadística & datos numéricos , Femenino , Humanos , Masculino , Música , Noruega/epidemiología , Atención Primaria de Salud/estadística & datos numéricos , Derivación y Consulta/estadística & datos numéricos , Recursos Humanos , Heridas y Lesiones/epidemiología , Heridas y Lesiones/terapia
11.
Eur Arch Otorhinolaryngol ; 264(11): 1289-94, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17530269

RESUMEN

Nasal blockage is a common complaint in Family Practice. Decongestive nosedrops are frequently employed therapeutic measures. Due to a considerable risk of abuse and side effects, alternatives are wanted. The purpose of this study was to elucidate to what extent ENDS might represent an alternative to decongestive nose sprays (DNS). The effects of DNS (xylometazolin) and ENDS (BreatheRight) on subjective and objective nasal blockage were compared in 89 patients. Main outcome measures were recordings of nasal symptom scores on visual analogue scales (VAS), minimal cross-sectional areas (MCA) and nasal cavity volumes (NCV) as measured by acoustic rhinometry (AR), and peak nasal inspiratory flow (PNIF). ENDS significantly increased the MCA and the NCV in the anterior 0.0-3.0 cm of the nose compared to DNS, but had no effect on MCA from 3.0 to 5.4 cm behind the nostrils. In contrast to DNS, ENDS had no effect on the posterior NCV. ENDS and DNS gave comparable increase in nasal inspiratory flow as measured by PNIF, and in the subject's own experience of nasal obstruction. ENDS may represent an alternative to DNS as a measure against nasal blockage.


Asunto(s)
Dilatación , Imidazoles/uso terapéutico , Descongestionantes Nasales/uso terapéutico , Obstrucción Nasal/terapia , Tiras Reactivas/uso terapéutico , Administración Intranasal , Administración Tópica , Adulto , Femenino , Humanos , Imidazoles/administración & dosificación , Masculino , Descongestionantes Nasales/administración & dosificación , Obstrucción Nasal/tratamiento farmacológico
12.
Environ Sci Technol ; 40(21): 6601-7, 2006 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-17144284

RESUMEN

Weekly high-volume air samples were collected between 2000 and 2003 at six Arctic sites, i.e., Alert, Kinngait, and Little Fox Lake (LFL) in Canada, Point Barrow in Alaska, Valkarkai in Russia, and Zeppelin in Norway. Hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were quantified in all samples. Comparison showed that alpha-HCH and HCB were homogeneously distributed in the circumpolar atmosphere and uniform throughout the seasons. However, significantly higher atmospheric concentrations of alpha-HCH and HCB and strongertemperature dependence of alpha-HCH and gamma-HCH were found at LFL in Yukon (YK), which is unique among the sites by virtue of its high altitude and low latitude, resulting in higher precipitation rates and summer temperatures. Strong temperature dependence of alpha- and gamma-HCH at this location suggests that secondary emissions, i.e., re-evaporation from surfaces, were more important at this site than others. It is hypothesized that a higher precipitation rate at LFL facilitated the transfer of alpha-HCH from the atmosphere to surface media when technical HCH was still in use worldwide. On the other hand, higher temperature at LFL enhanced reevaporation to the atmosphere after the global ban of technical HCH. In contrast to alpha-HCH and HCB, larger spatial and seasonal differences were seen for gamma-HCH (a currently used pesticide), which likely reflect the influence of different primary contaminant sources on different Arctic locations. Fugacity ratios suggest a net deposition potential of HCB from air to seawater, whereas seawater/air exchange direction of alpha-HCH varies in the circumpolar environment.


Asunto(s)
Contaminantes Atmosféricos , Atmósfera , Monitoreo del Ambiente/métodos , Hexaclorobenceno/análisis , Hexaclorociclohexano/análisis , Plaguicidas/análisis , Estaciones del Año , Regiones Árticas , Ambiente , Hidrocarburos Clorados/análisis , Control de Calidad , Agua de Mar , Propiedades de Superficie , Temperatura
13.
Environ Sci Technol ; 40(10): 3217-22, 2006 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-16749684

RESUMEN

Polycyclic aromatic hydrocarbon (PAH) air concentrations measured over the period 1992-2000 at the Canadian High Arctic station of Alert were subject to time-series analysis using dynamic harmonic regression (DHR). For most of the PAHs, the DHR model fit to the observed data was good, with DHR capable of interpolating over missing data points during periods when air concentrations were below detection limits. As expected, DHR identified seasonal increases in PAH air concentrations. However, it has also identified additional, subtler "seasonal" patterns as a series of harmonics with varying periodicity. For example, a regular summer high in air concentrations was apparent for many PAHs, particularly the lower molecular weight (two- to three-ringed) compounds, which may be attributed to summertime regional combustion events such as forestfires and/or revolatilization from surfaces (e.g., soil and oceans, as well as arctic surfaces). Comparison of wintertime PAH concentrations (where sigmaPAH ranged from 260 to 516 pg m(-3)) with an earlier arctic study did not reveal a reduction in PAH levels. However, removal of the seasonal components by DHR revealed a declining trend in PAH concentrations over the 1992-2000 period. For many lighter PAHs, this was typified by a linear decrease over the whole time series, although, for the higher molecular weight PAHs, a marked reduction was apparent in the first few years of sampling followed by a leveling off in concentrations by the mid/late-1990s. This behavior is similar to reported trends of other air pollutants in the Arctic, may be attributed to the decline in Soviet industry during the early 1990s, and has implications regarding the major PAH sources affecting the Arctic.


Asunto(s)
Contaminantes Atmosféricos/análisis , Atmósfera/análisis , Monitoreo del Ambiente , Hidrocarburos Policíclicos Aromáticos/análisis , Regiones Árticas , Canadá , Estaciones del Año , Factores de Tiempo
14.
Environ Sci Technol ; 39(21): 8214-9, 2005 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-16294857

RESUMEN

The initial emission rate of volatile organic compounds (VOCs) from consumer products is important for assessing potential human exposure to VOCs in products. The vapor pressure and boundary layer (VB) model developed in the past was used to predict the emission rates of VOCs in the fast decaying phase from petroleum-based wet materials. This study has extended the model to largely water-based products. Study results have shown a good agreement (ratio = 1.01, r2 = 0.89) between model-predicted initial emission rates (ER0) of 2-butoxyethanol (2-BE) based on its equilibrium headspace concentration and experimentally measured ER0 in a small dynamic environmental chamber for 20 consumer products. These water-based products included wood surface treating stains, general cleaning agents, and degreasers with 2-BE concentrations over a wide range. The results also demonstrated a dependency between the headspace concentrations of the target analytes and the water content in the liquid. But dependency on water content had no effect on the use of headspace concentration to predict the ER0. The ER0 of 2-BE in the products ranged from 100 to 3000 mg m(-2) h(-1). In the majority of cases, the 2-BE concentration range in individual products indicated in the Material Safety Data Sheet agreed with the measured data.


Asunto(s)
Contaminantes Ambientales/análisis , Glicoles de Etileno/análisis , Cromatografía de Gases y Espectrometría de Masas , Control de Calidad , Volatilización
15.
Environ Sci Technol ; 38(21): 5514-21, 2004 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-15575266

RESUMEN

Archived extracts of weekly air samples collected at remote arctic monitoring stations at Alert and Tagish, Canada, and Dunai Island, Russia, in 1994-1995 were combined into 4-week composites and analyzed for levels and seasonal trends of polychlorinated naphthalenes (PCNs) and non- and mono-ortho-substituted polychlorinated biphenyls (PCBs). Mean annual sigmaPCN concentrations were 0.69, 0.82, and 0.38 pg/m3 at Alert, Dunai, and Tagish, respectively. PCNs exhibited a seasonal trend at Alert and Dunai, with higher levels occurring during winter when air masses originating over Eurasia influence the high arctic and coincide with the haze period. Episodic, trans-Pacific transport impacted PCN concentrations at Tagish. A seasonal trend was not evident for the non-/mono-o-PCBs. The contrary PCN and non-/mono-o-PCB trends indicate that the sources of these two compound classes to arctic air differ, and that atmospheric transport from source regions has a greater influence on PCN levels than for non-/ mono-o-PCBs. PCNs apparently originating from combustion sources contribute to levels in winter, as indicated by the presence of combustion marker congeners, but evaporative emissions from source regions are likely the dominant source. PCNs contributed 71 and 75% of dioxin toxic equivalents (TEQ) relative to the non-/mono-o-PCBs at Alert and Dunai and 30% at Tagish during the winter months, demonstrating the toxicological importance of PCNs as a compound class relative to PCBs.


Asunto(s)
Contaminantes Atmosféricos/análisis , Compuestos de Cloro/análisis , Naftalenos/análisis , Bifenilos Policlorados/análisis , Regiones Árticas , Canadá , Dioxinas/análisis , Incineración , Naftalenos/química , Federación de Rusia , Estaciones del Año , Volatilización
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