1,721,133 research outputs found
Environmental distribution of mercury and other trace elements in the geothermal area of Bagnore (Mt. Amiata, Italy)
No full textThe environmental distribution of mercury and other trace elements in the geothermal area of Bagnore (Mt. Amiata, central Italy) and its surroundings was evaluated by means of lichens used as bioaccumulators. Adopting a 'before-after' strategy, the impact of a recently built power plant was also evaluated. Four sites were sampled: (1) S. Fiora, a town 2 km SE of Bagnore; (2) Bagnore, a village where geothermal power is generated; (3) Aiole, a locality 1.5 km NW of Bagnore with an abandoned Hg smelting plant and a waste pile of roasted cinnabar; (4) Arcidosso, a town 3.5 km NW of Bagnore. At S. Fiora and Arcidosso, where most of the population is concentrated, mercury levels in lichens were within the background range (0.1-0.2 μg/g dw). On the contrary, at Aiole, Hg concentrations (0.63-0.67 μg/g dw) were much higher than background. After the new geothermal power plant went into operation at Bagnore, lichen concentrations of rig showed a 50% increase from 0.22 to 0.32 μg/g dw. This value, however, is in line with those found in lichens from natural areas with hot springs and fumaroles. © 2001 Elsevier Science Ltd. All rights reserved
Lichens as bioindicators of geothermal air pollution in central Italy
No full textThe suitability of lichens as bioindicators of geothermal air pollution was evaluated in central Italy. Fifty-one sites were sampled in the Travale-Radicondoli geothermal field, an area of about 15 km2. Lichens on 1-5 trees per station were sampled, using 30 × 50 cm grids on tree boles, where lichens were most dense. Index of Atmospheric Purity (IAP) was calculated as the sum of the frequencies of all lichen species present at the station. Using automatic mapping programs, the area was divided into four air quality zones and the lowest IAP values were found within about 500 m of geothermal power plants. No direct measurements of air pollution are available for the whole study area, however, other studies show that air pollution levels (mercury, boron) fall with distance from a geothermal source. Also no substrate parameter (height, circumference, bark pH, and buffer capacity of the trees) discriminates between IAP zones. This suggests that air pollution arising from geothermal emissions is responsible far the zonation shown, with values for species richness and IAP rising with distance from geothermal installations. It is concluded that lichens are reliable bioindicators of geothermal air pollution. Copyright © 1996 by the American Bryological and Lichenological Society, Inc
Lichen bioindication of air quality in the Mt. Amiata geothermal area (central Italy)
No full textThe results of a lichen bioindication survey of air quality performed
in the Mr. Amiata geothermal area (Tuscany, central Italy) are reported. On the
basis of 153 Index of Atmospheric Purity (IAP) samplings, an air quality zonal
map of the area was drawn. The lowest IAP values were recorded in an area
encompassing the geothermal power plants, up to a distance of about 500 m.
The overall pattern of rising IAP values with increasing distance from the
geothermal power plants suggested that air pollution from the geothermal
installations is the main cause of the observed zonation of lichen communities.
It is suggested that hydrogen sulphide is the main contaminant responsible for
lichen decline around geothermal power plants
Lichens from the Lake Burano Nature Reserve (Tuscany, Central Italy)
No full text48 species of lichens are reported from the Burano Lake Nature Reserve. Three taxa are new to the Region of Tuscany. The lichen florula of the Nature Reserve is characterized by a relatively high incidence of mediterranean species of humid habitats
Lichens and mosses as biomonitors of trace elements in areas with thermal springs and fumarole activity (Mt. Amiata, central Italy)
No full textThe contribution of thermal springs and fumaroles to environmental levels of Al, As, B, Cd, Cu, Fe, Hg, Mo, Pb, S, Sb and Zn was evaluated by means of lichens (Parmelia sulcata) and mosses (Hypnum cupressiforme) used as bioaccumulators. Compared to the data reported for unpolluted areas, accumulation of Hg, S and Al was found, with values of Hg and S in the same range as in the vicinity of geothermal power plants. Furthermore, fumaroles turned out to be a significant source of atmospheric arsenic
Lichen biomonitoring of trace elements in a geothermal area (central Italy)
No full textThe epiphytic lichen Parmelia caperata was used systematically to biomonitor trace elements in the Travale-Radicondoli geothermal field (central Italy). The results showed a very low occurrence of potentially toxic heavy metals such as Cd, Hg and Ph, and relatively high values for As, B, Mo and elements associated with soil dust (Al, Co, Cr, Fe, Mn and Ni). Boron was the principal element of geothermal origin. Arsenic seems to originate both from power plants and adjacent thermal springs. It is concluded that trace element pollution in the area is low
Lichens as long–term biomonitors of air quality in central Italy
No full textThe results of a long-term study (data of 1978 and 1993) performed in central Italy using epiphytic lichens both as indicators and monitors (accumulators) are presented. Floristic data showed that air quality in the study area did not change markedly in this 15-year period and is currently fairly good. Similarly, the concentrations of trace elements in Parmelia caperata thalli showed no substantial change, with values similar to those in lichens of unpolluted areas. The concentration of Cs-137 in P. caperata and Lobaria pulmonaria thalli doubled after the Chernobyl accident, but was low compared to other European areas
Fragmentation of Mediterranean oak forests affects the diversity of epiphytic lichens
No full textThe present study investigated a fragmented Mediterranean oak forest to evaluate so called edge effect on species richness and composition of epiphytic lichen communities colonizing tree trunks.
The results showed that in Mediterranean oak forest patches, epiphytic lichen diversity and communities are significantly influenced by microlimatic variables related to the edge effect. Light influx rather than atmospheric humidity and temperature was the main driving factor affecting lichen diversity along the forest edge-interior gradient, while humidity is the prevailing factor inside the forest. It is concluded that forest fragmentation may have a heavy impact of epiphytic lichens, with the reduction and disappearance of typical forest species and the appearance of ubiquitous tolerant species, with an overall impoverishment and banalization of the lichen flora
Epiphytic lichens and bryophytes of forest ecosystems in Tuscany (C. Italy)
No full textThe distribution of epiphytic bryophytes and lichens on three species of trees (Quercus ilex, Quercus cerris and Fagus sylvatica, representing the forest ecosystems of central Italy at low, medium and high elevations, respectively) was examined with respect to host specificity and habitat differences. Although most species were host-specific, the results suggested that habitat characteristics are more important than phorophyte properties in determining the distribution of lichens and bryophytes. Factors affecting the diversity of the epiphytic flora were different for lichens and bryophytes. In the case of lichens, climatic parameters and forest monospecificity were important factors, whereas tree cover (i.e. shade) and to a certain extent the number of available trees seemed more important for bryophytes
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