خيارات البحث
النتائج 1 - 10 من 39
Les lichens bioindicateurs: la pollution acide dans la region lyonnaise.
1986
Belandria G. | Asta J.
Impact de la pollution atmospherique fluoree d' origine industrielle sur l' environnement de la region d' Annaba (Algerie) [usine d' engrais phosphates].
1987
Semadi A.
Uptake, retention and toxicity of heavy metals in lichens. A brief review.
1989
Tyler G.
Epiphytic lichens as air quality indicators in forest stands
2002
Mavsar, R. (Slovenian Forestry Institute, Ljubljana (Slovenia)) | Batic, F. | Jeran, Z.
An outline of the analyses of experimental material from the 2000 moss survey is given. It includes some selected areas in Central Russia, Bosnia, Bulgaria, Romania, Slovakia and Serbia. Applying this methodology to areas of Central and Eastern Russia, not yet covered by the European moss surveys, will significantly broaden our understanding of air pollution in Europe
اظهر المزيد [+] اقل [-]The ecological impact of mineral exploitation in the Russian Arctic: A field-scale study of polycyclic aromatic hydrocarbons (PAHs) in permafrost-affected soils and lichens of the Yamal-Nenets autonomous region
2019
Ji, Xiaowen | Abakumov, Evgeny | Polyako, Vyacheslav | Xie, Xianchuan | Dongyang, Wei
Forty soil and lichen samples and sixteen soil horizon samples were collected in the mining and surrounding areas of the Yamal-Nenets autonomous region (Russian Arctic). The positive matrix factorization (PMF) model was used for the source identification of PAHs. The results of the source identification showed that the mining activity was the major source of PAHs in the area, and that the mining influenced the surrounding natural area. The 5+6-ring PAHs were most abundant in the mining area. The lichen/soil (L/S) results showed that 2+3-ring and 4-ring PAHs could be transported by air and accumulated more in lichens than in the soil, while 5+6-ring PAHs accumulated more in the soil. Strong relationships between the quotient of soil/lichen (QSL) and Log KOA and Log PL and between the quotient of lichen/histic horizon soil and KOW were observed. In addition, hydrogeological conditions influenced the downward transport of PAHs. Particularly surprising is the discovery of the high levels of 5 + 6 rings in the permafrost table (the bottom of the active layer). One hypothesis is given that the global climate change may lead to further depth of active layer so that PAHs may migrate to the deeper permafrost. In the impact area of mining activities, the soil inventory for 5+6-ring PAHs was estimated at 0.14 ± 0.017 tons on average.
اظهر المزيد [+] اقل [-]Comparing early twentieth century and present-day atmospheric pollution in SW France: A story of lichens
2013
Agnan, Y. | Séjalon-Delmas, N. | Probst, A.
Lichens have long been known to be good indicators of air quality and atmospheric deposition. Xanthoria parietina was selected to investigate past (sourced from a herbarium) and present-day trace metal pollution in four sites from South-West France (close to Albi). Enrichment factors, relationships between elements and hierarchical classification indicated that the atmosphere was mainly impacted by coal combustion (as shown by As, Pb or Cd contamination) during the early twentieth century, whereas more recently, another mixture of pollutants (e.g. Sb, Sn, Pb and Cu) from local factories and car traffic has emerged. The Rare Earth Elements (REE) and other lithogenic elements indicated a higher dust content in the atmosphere in the early twentieth century and a specific lithological local signature. In addition to long-range atmospheric transport, local urban emissions had a strong impact on trace element contamination registered in lichens, particularly for contemporary data.
اظهر المزيد [+] اقل [-]Biomonitors of urban air pollution: Magnetic studies and SEM observations of corticolous foliose and microfoliose lichens and their suitability for magnetic monitoring
2013
Chaparro, Marcos A.E. | Lavornia, Juan M. | Chaparro, Mauro A.E. | Sinito, Ana M.
This study explored the suitability of available lichen species as air pollution biomonitors and assessed their potential for magnetic monitoring in cities. Several lichens on tree bark were collected in urban and industrial sites from Tandil city, as well as control sites. The results showed that magnetite-like minerals were the main magnetic carriers in all sites and samples. However, the concentration varied between clean and polluted sites. In addition, magnetic-grain size-distribution showed clear differences between sites. Observations by scanning electron microscopy showed different particles in a variety of shapes and grain sizes; moreover, the presence of iron oxides and several toxic elements was detected by energy dispersive spectroscopy analysis. Although eleven lichen species were identified that appeared suitable for use as air-pollution monitors, three of them, Parmotrema pilosum, Punctelia hipoleucites and Dirinaria picta, occurred more frequently in the area, thus constituting appropriate species for future monitoring in the study area.
اظهر المزيد [+] اقل [-]Elemental composition of Usnea sp lichen from Potter Peninsula, 25 de Mayo (King George) Island, Antarctica
2016
Bubach, Débora | Catán, Soledad Perez | Di Fonzo, Carla | Dopchiz, Laura | Arribére, Maria | Ansaldo, Martin
Several pollutants, which include metals, are present in the Antarctic atmosphere, snow, marine and terrestrial organisms. This work reports the elements incorporated by Usnea sp thalli in Potter Peninsula, 25 de Mayo (King George) Island, South Shetlands, Antarctica. Geological origin was analyzed as possible sources of elements. For this purpose, correlations were done using a geochemical tracer, principal component analysis and enrichment factors were computed. Lithophile elements from particulate matter were present in most of the sampling sites. Bromine, Se and Hg showed the highest enrichment factors suggesting other sources than the particulate matter. Mercury values found in Usnea sp were in the same range as those reported for Deception Island (South Shetlands) and remote areas from the Patagonia Andes.
اظهر المزيد [+] اقل [-][Impact of fluorated atmospheric pollution of industrial origin on the environment in the region of Annaba (Algeria) [phosphate fertilizer factory]]
1987
Semadi, A. (Universite d'Annaba (Algeria). Institut des Sciences de la Nature)