20 research outputs found
Maria Nallino (1908-1974) and the Birth of Arabic and Islamic studies at Ca’ Foscari
This essay, based on bibliographic and archival material, focuses on the academic figure Maria Nallino, a scholar whose voluminous body of work ranges from classicism to modernity with equal fluency and expertise. Daughter of the famous Orientalist Carlo Alfonso Nallino (1872-1938), whose work she gathered and actively promoted, her arrival at Ca’ Foscari (1962) inaugurated Arabic and Islamic studies in Venice
Human contribution to trace elements in urban areas as measured in holm oak (Quercus ilex L.) bark
The effect of human activities on the presence of trace elements in the atmosphere was evaluated by analyzing samples of holm oak bark, collected in Italy in a large city, in a small town, and in a reference area, scarcely inhabited. In all cases, point sources of pollution were excluded (e.g., industries and incinerators). The concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, Pb, V, and Zn were measured using inductively coupled plasma optical emission spectrometry (ICP-OES). The element concentrations in the small town are not different from the reference area, except for Pb and Cu, while the samples collected in the large city show higher concentrations of Co, Cu, Fe, Ni, Pb, V, and Zn with respect to the rural area. In particular, the Pb levels in the large city are approximately 16 times higher than in the reference site, and five times higher than in the small town. Most element concentrations are correlated in the large city, while in the reference site, only a few significant correlations between elements were found. Even in the absence of specific sources of pollution, populations living in big cities are exposed to higher concentrations of trace elements than those living in rural environments or in small urban centers
Urban and industrial contribution to trace elements in the atmosphere as measured in holm oak bark.
The concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn were measured by ICP-OES in samples of bark of the holm oak (Quercus ilex L.) collected from trees in different urban environments (residential and mixed residential/industrial). The use of tree bark as a bioindicator makes it easy to create maps that can provide detailed data on the levels and on the spatial distribution of each trace element. For most of the elements considered (As, Co, Fe, Mn, Ni, V and Zn), the concentrations in the industrial sites are about twice (from 1.9 to 2.8 times higher) of those in the residential area. Arsenic, Fe and Zn show the highest concentrations near a steel plant (operational until 2005), but for the other elements it is not possible to identify any localized source, as evident from the maps. In areas where urban pollution is summed up by the impact of industrial activities, the population is exposed to significantly higher amounts of some metals than people living in residential areas
Trace elements in Plantago lanceolata L., a plant used for herbal and food preparations: new data and literature review
Plantago lanceolata L. is a common grassland and roadside plant, widely used in many countries in food and herbal preparations. In this study, samples of this wild plant were collected from rural, suburban/urban, and industrial environments; the concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, P, Pb, V, and Zn were measured in the edible parts of the plant (leaves), in the roots, and in the soils in order to calculate the bioaccumulation and translocation factors. The data obtained were compared with literature data available. Except for samples collected near mines and smelting plants, where Cd, Pb, and Zn concentrations were up to 15 times higher, in all other cases, no differences were observed with respect to samples from rural areas, except for Pb concentration, which was 3 times higher in urban areas. In the samples collected in our study area, the metal content does not pose particular health risks; however, even within a quite restricted region like the investigated area, high metal concentrations, possibly due to the presence of particular substrates, were observed in some samples collected from areas considered "clean" and suitable for wild food plant gathering
The bark of the branches of holm oak (Quercus ilex L.) for a retrospective study of trace elements in the atmosphere
Tree bark has proved to be a useful bioindicator for trace elements in the atmosphere, however it reflects an exposure occurring during an unidentified period of time, so it provides spatial information about the distribution of contaminants in a certain area, but it cannot be used to detect temporal changes or trends, which is an important achievement in environmental studies. In order to obtain information about a known period of time, the bark collected from the annual segments of tree branches can be used, allowing analyses going back 10\u201315 years with annual resolution. In the present study, the concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, Pb, V and Zn were measured by atomic emission spectrometry in a series of samples covering the period from 2001 to 2013 in an urban environment. Downward time trends were significant for Cd, Pb and Zn. The only trace element showing an upward time trend was V. The concentrations of the remaining six trace elements were constant over time, showing that their presence in bark is not simply proportional to the duration of exposure. This approach, which is simple, reliable and widely applicable at a low cost, allows the \u201ca posteriori\u201d reconstruction of atmospheric trace element deposition when or where no monitoring programme is in progress and no other natural archives are available
Temporal trends (1981\u20132007) of trace and rare earth elements in the lichen Cetraria islandica (L.) Ach. from Italian herbaria
Twenty-four herbarium specimens of Cetraria islandica collected in Italy from 1981 to 2007 were used for
retrospective analysis. Cd, Ce, Cu, Fe, Gd, La, Mn, Ni, Pb, Sb, V, Y, and Zn concentrations were measured. Pb
showed a negative temporal trend, linked to the ban of leaded fuel for vehicles. Pb showed a negative
correlation with the distance of the sampling sites from a highway in the years before 1995 and no
relationship after that year, corresponding to the Pb content reduction in gasoline. A significant trend
towards increasing Mn concentrations over time also emerged, which deserves further investigations
due to Mn toxicity. Cluster analysis showed a group of elements of anthropogenic origin, while rare earth
elements formed a separated cluster of natural origin. Lichens from herbaria proved to be a valuable tool
for reconstructing historical trends in trace element deposition, highlighting variations produced by
human activities
Branch bark of holm oak (Quercus ilex L.) for reconstructing the temporal variations of atmospheric deposition of hexavalent chromium
The bark from the annual segments of the branches of holm oak (Quercus ilex L.) is exposed to trace element deposition for a known period of time and thus it is a possible candidate as a bioindicator for reconstructing historical changes in pollution. A series of samples were analysed for Cr(VI) concentration by electrothermal atomic absorption spectrometry (ET-AAS) after selective extraction in a sodium carbonate solution. In this way the atmospheric deposition of Cr(VI) was reconstructed from 2001 to 2010 in an area where an industrial plant produced Cr(VI) compounds until 2003. The present study shows the potential of this type of sample as a natural archive for persistent pollutants, useful for monitoring changes that occur before a monitoring programme is established, with the advantage of being easy to collect almost everywhere
The bark of holm oak (Quercus ilex, L.) for airborne Cr(VI) monitoring
In this work, the bark of holm oak was used as a bioindicator to study the atmospheric distribution of
Cr(VI). The chosen method (alkaline extraction and atomic absorption determination) was found in the
literature, adapted for use with the matrix involved, and validated. The method had some limits, but
provided an excellent estimation of Cr(VI) concentrations with good sensitivity and a reasonable time
of analysis and cost. Thirty-four samples of holm oak collected in three areas characterised by different
possible sources of pollution (the area near a former chromate production plant, an urban area, and a
rural \u2018\u2018reference\u2019\u2019 area) were analysed, obtaining concentrations ranging from 1.54 to 502 lg g1 near
the industrial plant, ranging from 0.22 to 1.35 lg g1 in the urban area, and mostly below the detection
limit (0.04 lg g1) in the rural area. The bark of holmoak proved to be a good bioindicator to detect Cr(VI)
in the environment. The extraction procedure followed by atomic absorption analysis is simple, provides
good sensitivity, and it is suitable for environmental studies
Is there a risk of trace element contamination in herbal preparations? A test study on the lichen Cetraria islandica
Lichens are a source of unique secondary metabolites, which have been proved to have many biological properties with possible pharmaceutical roles, including e.g. antioxidant, antimicrobial, antifungal or anti-inflammatory activities and to be worth of consideration for potential human use. However, lichens lack cuticolar tissues and are exposed to several atmospheric contaminants, including trace elements. This work aims at exploring the potential toxicity of herbal preparations derived by the lichen Cetraria islandica due to trace element contamination, testing whether different concentrations may be observed, depending on the origin of the raw material. Fourteen samples of C. islandica, as cut dried thalli occurring on the European market, have been bought from different providers. For each sample, the concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, P, Pb, V and Zn were measured on comminuted herbal substance and on the corresponding decoction, using atomic emission spectrometry (ICP-OES). The elemental concentrations in decoctions were significantly lower than those measured in raw materials, dropping down to levels of negligible health concern. Differences observed in raw materials were not observed anymore in the corresponding decoctions. Also, the elemental transfer rate from dried lichen to decoction was extremely element-specific, ranging from 2% for Cu to 95% for Zn