1,721,002 research outputs found
Memories of Professor Aristeo Renzoni
No full textHere were reported Memories of Professor Aristeo Renzoni, University of Siena. Among the first Professors of Ecology in Italy and internationally recognized scientist. In almost 60 years of research he published over 250 scientific papers. The main ecological and environmental topics of his research were the histology of reproductive structures of bivalves, the histology of the pineal gland in birds, the accumulation of mercury in large pelagic predators of Mediterranean Sea, the contamination of organochlorine compounds in bird eggs, the lead shot pollution from hunters activities in wetlands
Valutazione preliminare sul grado di contaminazione nel lago di Lesina utilizzando alcuni biomarkers.
No full textMercurio e selenio nelle uova di Larus cachinnans e Larus audouinii (Laridae) dell'Arcipekago Toscano e della Sardegna
No full textPapillifera papillaris (O.F. Müller), a small snail living on stones and monuments, as indicator of metal deposition and bioavailability in urban environments
No full textAlthough mosses, lichens and vascular plants are widely used as biomonitors of metal deposition in urban environments, these organisms also accumulate soil and rock dust particles making difficult the recognition of metal sources and their bioavailability to consumers. Based on the assumption that a stationary, widespread and omnivorous animal species, scarcely interacting with soil and inhaling fine particles, could be a much more reliable indicator of metal deposition and bioavailability in urban environments, we analyzed for the first time the elemental composition of soft tissues and excreta of a pulmonate gastropod, Papillifera papillaris (O.F. Müller), commonly dwelling on stone walls and monuments in Italian and Mediterranean urban environments. Snails and some moss species were collected in 2014 and 2015 from stone- and brick-walls at the side of roads with different traffic intensity and in control sites. Results showed that the soft tissues of P. papillaris, purged of the gut contents, accumulated much higher Cd, Cu, Mn, Pb, and Zn levels than mosses from the same walls and concentrations of these metals were significantly higher at the side of roads with higher traffic intensity. Mollusk excreta had very high concentrations of Al, Cr, Fe, Ni and Pb, suggesting that a large proportion of elements associated to soil or stone particles, or with the black crusts scraped from walls, is not absorbed in the digestive tract. Surprisingly, P. papillaris tissues accumulated much higher Mn concentrations than those reported in literature for other species of terrestrial gastropods. Although preliminary, this study indicates that P. papillaris is a very promising species to monitor metal deposition pattern and bioavailability in urban environments and to evaluate the possible metal transfer along food chains
Differential elemental stoichiometry of two Mediterranean evergreen woody plants over a geochemically heterogeneous area
No full textLeaf nutrient composition and stoichiometry reflect complex interactions of the plant with its environment and are useful traits to explore ecological processes and relationships. In the present study, the foliar elemental compositions of two common Mediterranean woody species, the evergreen broad-leaved Quercus ilex and the coniferous Pinus pinaster growing in an area of Central Italy known for geochemical and geothermal anomalies, were investigated. To assess the site-specific and age-dependent pattern of foliar composition and stoichiometry, macronutrients (C, N, P, K, Mg, S) and trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Sb, V, Zn) were determined in leaves and needles of three different ages (6-, 12- and 24-month-old) collected from metalliferous (geothermal, mining) and rural areas. Leaves of Q. ilex showed comparatively high concentrations of micronutrients (i.e., Cu, Fe and Zn), while needles of P. pinaster accumulated significantly high concentrations of potentially toxic elements (i.e., As, Pb and S). No significant trend was found in elemental concentrations in relation to the age of leaves and needles. Multi-element stoichiometry of P. pinaster was driven by the geochemical heterogeneity of the sites, suggesting plastic adaptation at the sites with the most selective edaphoclimatic conditions (i.e., patches with nutrient poor and metalliferous soils). On the other hand, the content of both nutrients and potentially toxic elements in Q. ilex leaves varied little across the study area, reflecting stoichiometric stability; this is consistent with the ecophysiological features of Q. ilex as a late-successional species with a dominant role in the ecosystems of the Mediterranean area. Our findings demonstrate the value of foliar stoichiometric traits for understanding plant adaptation in a heterogeneous environment and also the consequences of biotic interactions during succession
Tree-rings analysis to reconstruct atmospheric mercury contamination at a historical mining site
Full text linkMercury (Hg) is a global environmental concern due to its toxicity (especially high
in methylated form) and the long-range distribution of its gaseous elemental
form (GEM). Hg-contaminated areas, such as abandoned mining sites, pose
intrinsic difficulties for their management and heavy monitoring costs. In these
environments, plant-based solutions may play a key role in the ecosystem quality
assessment and support remediation strategies, combining reliability and costeffectiveness. In this study, we adopted a biomonitoring approach by using tree
rings of four different species collected in the proximity of the miningmetallurgical area of Abbadia San Salvatore, central Italy, a major former Hg
mining district whose reclamation is currently in progress. Our dendrochemical
analysis was aimed at identifying the historical changes of local atmospheric Hg
contamination and at singling out, for the first time in the study area, other
potentially toxic elements (PTEs) associated with the past mining activity.
Collected cores dated back to early as 1940 and provided the temporal
patterns of atmospheric Hg emission vs the produced liquid quantities, so
reconstructing the historical impact of the mining site on nearby terrestrial
ecosystems and resident human population. Current GEM contamination was
found about twenty times lower than that of the fully operational mine periods.
From a first survey on other PTEs, thallium (Tl) and lead (Pb) appeared to be
potentially associated with the mining activity, thus suggesting new working
assumptions for further dendrochemical analyses and for the inclusion of Pb in
human biomonitoring surveys of the Mt. Amiata area, actually not present in the
control list. The results prompt a more thorough assessment by tracking for a
longer time span a critical site that is an ideal open-field lab to study the
ecophysiology of different tree species in relation to environmental behavior of
PTEs for better-assessing wildlife and human exposures
Lichen transplants as indicators of gaseous elemental mercury concentrations
Full text linkLichens play an important role in the biogeochemical cycling of mercury (Hg) and are commonly used as indicators of Hg enrichment in remote and anthropogenically impacted environments. To assess their capacity for Hg uptake and accumulation, we determined the concentration of gaseous elemental mercury (GEM) in air and the concentration of total Hg (THg) in transplanted thalli of two lichen species. Lichen transplants and passive air samplers (PASs) were concurrently deployed, side by side, at 10 sites within an abandoned mining area, characterized by large gradients in atmospheric Hg contamination. Highly variable time-weighted GEM concentrations determined by the PASs, ranging from 17 to 4,200 ng/m3, were mirrored by generally high Hg concentrations in transplanted thalli of both Xanthoria parietina (174–8,800 ng/g) and Evernia prunastri (143–5,500 ng/g). Hg concentrations in the two species co-varied linearly indicating about 60% greater Hg accumulation in X. parietina than in E. prunastri. Whereas Hg uptake in the fruticose E. prunastri increased linearly with GEM, a power law equation with a fractional exponent described the uptake in the foliose X. parietina. Extrapolating the relationships observed here to higher GEM levels yielded concentrations in lichen that agree very well with those measured in an earlier fumigation experiment performed under laboratory-controlled conditions. The uptake model of X. parietina was further verified by correctly estimating GEM concentrations from the THg measured in autochthonous thalli collected from the urban area adjacent to the mine site. Passive sampling can effectively provide time-weighted data of suitable spatial resolution to quantitatively describe GEM assimilation by lichens. Therefore, the combined use of passive sampling and lichen transplants can contribute to a more comprehensive understanding of the role of lichens, and potentially also of other cryptogams, in the deposition of atmospheric Hg to terrestrial ecosystems
Air quality in post-mining towns: tracking potentially toxic elements using tree leaves
Full text linkIn this study, leaves of the evergreen holm oak Quercus ilex were used to assess airborne contamination of potentially toxic elements (PTEs) at five towns located on the slopes of the Mt. Amiata (central Italy), an area with a long history of mining and, more recently, an important district for the industrial exploitation of geothermal energy. PTE composition and covariance of washed and unwashed Q. ilex leaves of three different ages (6, 12 and 24 month-old) were used to identify atmospheric inputs of PTEs at residential areas, evaluate long-term adsorption and retention of PTEs by the leaves, thus providing an indication of potential human exposure. Moreover, the determination of foliar concentrations of major elements (C, N, S and P) allowed an assessment of the nutritional status of the investigated urban tree stands which excluded the existence of stress condition caused by air pollution or other disturbances. Results indicated that overall Pb, Cu, and Cd concentration were low in the investigated urban sites, if compared with similar studies conducted in larger Italian cities, denoting a low contribution of vehicular traffic to the atmospheric pathway. The five urban settlements were characterized by a specific profile of elements (Al, Ba, Hg and Sb) enriched in unwashed leaves, resulting from the distinct geochemical characteristics of the area and from diffuse (i.e., urban activity) and point sources of PTEs emission (i.e., brownfields, geothermal power plants). The latter sources primarily govern the distribution of Hg, whose contamination was found to be very localized close to a major abandoned mining area. Our data provided quantitative evidence of the spectrum of PTEs potentially impacting resident population and may prove useful in support of follow-up instrumental monitoring campaigns of air quality, as well as for human health and ecological risk assessments
Temporal and geographical variations of mercury and selenium in eggs of Larus michahellis and Larus audouinii from central Mediterranean islands
No full textIn this study, we determined mercury and selenium levels in abandoned unhatched eggs of the yellow-legged gull (Larus michahellis) and Audouin’s gull (Larus audouinii) collected during 2004–2005 from the Tuscan archipelago and Sardinia (Italy). The different feeding habits of the two species probably determine the different uptakes of trace elements, as the study shows highly significant differences for selenium and mercury levels as well as shell thickness and Hg:Se molar ratio values. Audouin’s gulls nesting on the coasts of the Tuscan archipelago showed significantly higher selenium levels than did gulls from colonies from the islands around Sardinia. Comparisons with a similar investigation previously conducted in the same area suggested that mercury and selenium concentrations, although in line with reports in the literature, were significantly lower than levels encountered in gulls in the early 1980s. Mercury (mg/kg d.w.) dropped from 8.631 to 5.030 in Audouin’s gulls and from 2.509 to 0.828 in yellow-legged gulls. The regional decline in mercury levels following reduced use of the metal in industry and the probable food depletion effects linked to the overfishing of fish prey of these two gull species are discussed as hypotheses that could explain the decrease in mercury levels found in eggs
Evidenza di effetti estrogenici in esemplari mediterranei di pesce spada (Xiphias gladius): risultati delle indagini ecotossicologiche
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