scholarly journals Distribution Characteristics and Source of Dechloranes in Soil and Lichen of the Fildes Peninsula (Antarctica)

2018 ◽  
Vol 15 (10) ◽  
pp. 2312 ◽  
Author(s):  
Hui Gao ◽  
Guangshui Na ◽  
Yao Yao ◽  
Ruijing Li ◽  
Yuhang Gao ◽  
...  
Keyword(s):  
Long Range ◽  
Coastal Area ◽  
Emerging Contaminants ◽  
Atmospheric Transport ◽  
Regional Distribution ◽  
The Tibetan Plateau ◽  
Polar Regions ◽  
Distribution Characteristics ◽  
Fildes Peninsula ◽  
The Mean

Dechloranes (Decs) have been widely found in the environment, even in the Tibetan Plateau and remote polar regions. However, the understanding of their regional distribution characteristics in polar regions is limited. To study the long-range atmospheric transport and fates of these emerging contaminants, Decs were analyzed in soil and lichen from the Fildes Peninsula in Antarctica. The concentrations of five Decs in soil and lichen ranged from 141.46 to 838.47 pg/g dw and 237.04 to 3599.18 pg/g dw, respectively. The mean fractions of anti-Dechlorane Plus (DP) (fanti) values estimated in the current soils (0.37) and lichen (0.24) were lower than those of commercial products (fanti = 0.64–0.80), which confirms that long-range atmospheric transport is a main source of DP, and the DP burdens could be driven by the accumulation of syn-DP. The average ΣDP concentration in soil in the coastal area was higher than that in the inland area and Ardley Island, while in lichen, the average DP concentration at the Ardley Island site was approximately three-fold higher than that in the coastal area and inland areas. This indicates that the distribution of DP was influenced by anthropogenic interference and animal activities in the Fildes Peninsula. The spatial variation of fanti of the three regions was clearer in soil than that in lichen. The fanti values were negatively correlated with DP concentrations in soil, suggesting that DP concentration levels play an important role in determining the isomeric composition of DP in the soil.

scholarly journals Occurrence and Spatial Distribution of the Neutral Per-fluoroalkyl Substances, and Cyclic Volatile Methylsiloxanes in Atmosphere of the Tibetan Plateau

2018 ◽  
Author(s):  
Xiaoping Wang ◽  
Jasmin Schuster ◽  
Kevin C. Jones ◽  
Ping Gong
Keyword(s):  
Tibetan Plateau ◽  
Long Range ◽  
Atmospheric Transport ◽  
Grand Canyon ◽  
Capital City ◽  
The Tibetan Plateau ◽  
Transport Channel ◽  
Local Contribution ◽  
Remote Environment ◽  
Global Background

Abstract. Due to their properties of bioaccumulation, toxicity, and long-range atmospheric transport, poly and per-fluoroalkylsubstances (PFASs), and cyclic volatile methyl silxoanes (cVMS) are currently being considered as emerging persistent organic pollutants (POPs) for regulation. To date, there are limited data on PFASs and cVMS in the atmosphere of the Tibetan Plateau (TP), a remote environment which can provide information on global background conditions. Sorbent-impregnated polyurethane foam (SIP) disk passive air samplers were therefore deployed for three months (May to July 2011 and 2013) at 16 locations across the TP. Using previously reported methods for estimating the air volume sampled by SIP disks, the derived atmospheric concentrations ranged as follows: 18–565 ng/m3 for ∑cVMS (including D3, D4, D5, and D6); 65–223 pg/m3 for fluorotelomer alcohols (∑FTOHs); 1.2–12.8 pg/m3 for fluorinated sulfonamides (∑FOSA); and 0.29–1.02 pg/m3 for fluorinated sulfonamidoethanols (∑FOSE). The highest ∑cVMS occurred at Lhasa, the capital city of the TP, indicating the local contribution to the emerging pollutants. Higher levels of ∑FTOHs were observed at sites close to the transport channel of the Yarlung Tsangpo Grand Canyon, indicating possible long-range atmospheric transport (LRAT). Elevated concentrations of shorter-chain volatile PFAS precursors (4 : 2 FTOH and fluorobutane sulfonamidoethanol) were found in most air samples, reflecting the shift in production from long- to short-chain PFASs in Asia. Overall, concentrations of emerging POPs at background sites of the TP were 1–3 orders of magnitude higher than those reported for legacy POPs.

scholarly journals Occurrence and spatial distribution of neutral perfluoroalkyl substances and cyclic volatile methylsiloxanes in the atmosphere of the Tibetan Plateau

2018 ◽  
Vol 18 (12) ◽  
pp. 8745-8755 ◽  
Author(s):  
Xiaoping Wang ◽  
Jasmin Schuster ◽  
Kevin C. Jones ◽  
Ping Gong
Keyword(s):  
Tibetan Plateau ◽  
Long Range ◽  
Atmospheric Transport ◽  
Grand Canyon ◽  
Capital City ◽  
Perfluoroalkyl Substances ◽  
The Tibetan Plateau ◽  
Transport Channel ◽  
Remote Environment ◽  
Global Background

Abstract. Due to their properties of bioaccumulation, toxicity, and long-range atmospheric transport, polyfluoroalkyl and perfluoroalkyl substances (PFASs) and cyclic volatile methylsiloxanes (cVMSs) are currently being considered as emerging persistent organic pollutants (POPs) for regulation. To date, there are limited data on PFASs and cVMSs in the atmosphere of the Tibetan Plateau (TP), a remote environment which can provide information on global background conditions. Sorbent-impregnated polyurethane foam (SIP) disc passive air samplers were therefore deployed for 3 months (May to July 2011 and 2013) at 16 locations across the TP. Using previously reported methods for estimating the air volume sampled by SIP discs, the derived atmospheric concentrations ranged as follows: 18–565 ng m−3 for ΣcVMS (including D3, D4, D5, and D6); 65–223 pg m−3 for fluorotelomer alcohols (ΣFTOHs); 1.2–12.8 pg m−3 for fluorinated sulfonamides (ΣFOSA); and 0.29–1.02 pg m−3 for fluorinated sulfonamidoethanols (ΣFOSE). The highest ΣcVMS occurred at Lhasa, the capital city of the TP, indicating the local contribution to the emerging pollutants. Higher levels of ΣFTOHs were observed at sites close to the transport channel of the Yarlung Tsangpo Grand Canyon, indicating possible long-range atmospheric transport (LRAT). Elevated concentrations of shorter-chain volatile PFAS precursors (4 : 2 FTOH and fluorobutane sulfonamidoethanol) were found in most air samples, reflecting the shift in production from long- to short-chain PFASs in Asia. Overall, concentrations of emerging POPs at background sites of the TP were 1–3 orders of magnitude higher than those reported for legacy POPs.

scholarly journals Carbonaceous Matter in the Atmosphere and Glaciers of the Himalayas and the Tibetan Plateau: An Investigative Review

2021 ◽  
Author(s):  
Chaoliu Li ◽  
Fangping Yan ◽  
shichang kang
Keyword(s):  
Tibetan Plateau ◽  
Organic Carbon ◽  
Radiative Forcing ◽  
Atmospheric Transport ◽  
Climate Forcing ◽  
The Tibetan Plateau ◽  
Polar Regions ◽  
Carbonaceous Matter ◽  
Current Thinking ◽  
Atmospheric Transport Modeling

<p>Carbonaceous matter, including organic carbon (OC) and black carbon (BC), is an important climate forcing agent and contributes to glacier retreat in the Himalayas and the Tibetan Plateau (HTP). The HTP - the so-called “Third Pole” – contains the most extensive glacial area outside of the polar regions. Considerable research on carbonaceous matter in the HTP has been conducted, although this research has been challenging due to the complex terrain and strong spatiotemporal heterogeneity of carbonaceous matter in the HTP. A comprehensive investigation of published atmospheric and snow data for HTP carbonaceous matter concentration, deposition and light absorption is presented, including how these factors vary with time and other parameters. Carbonaceous matter concentrations in the atmosphere and glaciers of the HTP are found to be low. Analysis of water-insoluable organic carbon and BC from snowpits reveals that concentrations of OC and BC in the atmosphere and glacier samples in arid regions of the HTP may be overestimated due to contributions from inorganic carbon in mineral dust. Due to the remote nature of the HTP, carbonaceous matter found in the HTP has generally been transported from outside the HTP (e.g., South Asia), although local HTP emissions may also be important at some sites. This study provides essential data and a synthesis of current thinking for studies on atmospheric transport modeling and radiative forcing of carbonaceous matter in the HTP.</p>

scholarly journals Evidence of exactness of the mean-field theory in the nonextensive regime of long-range classical spin models

2000 ◽  
Vol 61 (17) ◽  
pp. 11521-11528 ◽  
Author(s):  
Sergio A. Cannas ◽  
A. C. N. de Magalhães ◽  
Francisco A. Tamarit
Keyword(s):  
Field Theory ◽  
Long Range ◽  
Mean Field Theory ◽  
Mean Field ◽  
Spin Models ◽  
Classical Spin ◽  
The Mean ◽  
Classical Spin Models

Cadmium concentrations in kidneys of sheep and cattle in Western Australia. 1. Regional distribution

1994 ◽  
Vol 45 (4) ◽  
pp. 851 ◽  
Author(s):  
PW Morcombe ◽  
DS Petterson ◽  
HG Masters ◽  
PJ Ross ◽  
JR Edwards
Keyword(s):  
Western Australia ◽  
Geometric Mean ◽  
Regional Distribution ◽  
Adult Cattle ◽  
Agricultural Region ◽  
Wet Weight ◽  
The Mean ◽  
Winter Annual ◽  
Rate Of Accumulation ◽  
Cattle And Sheep

A sample of 4973 kidneys from sheep stratified by age and shire of origin within the Agricultural Region of Western Australia, was analysed for cadmium (Cd) content during the period August 1989 to April 1991. The geometric mean Cd concentration in the kidney of hogget ewes was 0.9 mg/kg, in 4-tooth ewes 1.47 mg/kg and in adult ewes 3.34 mg/kg on a wet weight basis. The mean Cd concentrations of either ewe or hogget flocks from different Divisions of the Agricultural Region did not differ from each other. The annual increase in Cd concentration of kidney from hogget sheep was estimated to be 0-65 mg/kg. The rate of accumulation of Cd in kidney from cattle and sheep grazing the same properties was similar. Kidneys from a sample of 354 adult cattle from the Kimberley Region and 483 aged sheep from the Pastoral Region, both areas of unimproved rangelands, had geometric mean Cd concentrations of 0.15 mg/kg and 0-31 mg/kg respectively. A higher Cd concentration in flocks from the divisions adjacent to the Agricultural Region may have resulted from the establishment of some volunteer species of winter annual pastures in the rangeland.

scholarly journals Electrical Behaviour of Finely Divided Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 173-191 ◽  
Author(s):  
J. G. Paren ◽  
J. W. Glen
Keyword(s):  
Relaxation Times ◽  
Surface Adsorption ◽  
Frequency Dispersion ◽  
Polar Regions ◽  
Electrical Behaviour ◽  
Heterogeneous Nature ◽  
Glacier Ice ◽  
Bulk Relaxation ◽  
Adsorption Of Co ◽  
The Mean

Abstract The electrical behaviour of ice which has been finely ground and compressed was investigated during ageing in air and over a range of temperatures. The dielectric behaviour may be accurately represented as the sum of two elliptical relaxation spectra. The behaviour eventually stabilizes with similar activation energies for the mean relaxation time of each spectrum c. 0.25 eV, and the ratio of the relaxation times is ten in samples of density c. 0.42 Mg m-3. Arguments are presented on whether the higher-frequency dispersion is a consequence of the heterogeneous nature of the samples or is a bulk relaxation process. The similarities between the behaviour of such finely ground ice and of deposited snow and polar glacier ice are discussed. The extent to which the results may be attributed to surface adsorption of CO2 are examined by reference to measurements of the CO2 content of finely divided ice and ice from polar regions.

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