1,720,973 research outputs found
Identification of present-day and historical sources of mercury in a complex industrial area
No full textMercury levels were measured in soils and earthworms on behalf of a long-term
surveillance program of the emissions from the industrial area of Scarlino
(Southern Tuscany, Central Italy), where a municipal solid waste incinerator and
two main chemical plants are currently operating. The study aimed at establishing
preliminary soil data to be used as baseline for long-term monitoring of mercury
contamination of soil and soil biota and to assess eventual contribution of the
industrial emissions. Overall total mercury concentration of superficial soils (0-5
cm), collected from 44 sampling sites randomly selected within a circular area up to
1.5 km from the center of the industrial area, was in average 0.29 ± 0.27 μg g-1
. This
value, which remains well below the screening values (1 μg g-1
) for contaminated
soils set by the Italian regulatory framework for residential areas, is approximately
4-5 times higher than the European topsoil baseline (FOREGS) for mercury and
highlights a general enrichment of the metal in the area. This is mainly attributable
to widespread geochemical anomalies characterizing the Southern Tuscany and to
the historical mineral processing and smelting activities that have been carried out
in the Scarlino area until the mid-90s. The highest mercury concentrations were
found in soils from sampling sites in direct proximity of industrial/artisanal
activities, where concentrations up to 1.59 μg g-1 were reached. Average mercury
concentrations (0.25 ± 0.10 μg g-1
) from agricultural and grazing land soils were
also noticeable, although earthworms from the same sites did not show a significant
bioaccumulation of the metal (0.11 ± 0.09 μg g-1
). The generally elevated
concentrations and the high variability (overall coefficient of variation = 93%) of
mercury soil data from the Scarlino area are questioning the possibility to isolate the
influence of a single source of contamination in an environment with a long
industrialization history. This is currently prompting further research supported by
techniques for monitoring atmospheric depositions (i.e. biomonitoring, passive
sampling) to improve estimation of mercury contamination arising from different
possible sources in the Scarlino are
Metal(loid) enriched topsoils in a multiple land-use area in Tuscany (Italy): geogenic vs. anthropogenic contributions and associated health risk
No full textThe Piana di Scarlino is a partially refilled wetland in the SW of Tuscany
(Central Italy) which has hosted chemical and power plants since the
1960s. Presently, in the area there are urban settlements (the main urban
center, Follonica, has a population of approx. 25.000), farms, tourist
facilities, and industrial districts, mainly based on H2SO4 and TiO2
production as well as waste incineration. In the last two decades the soil
and groundwater of the Piana di Scarlino, have been found polluted with
arsenic (As) and heavy metals. This prompted local authorities to implement remediation measures and environmental monitoring programs
to protect the resident population and the local agricultural produce. In
2013, we initiated an environmental surveillance program in the area
within an IPPC permitting procedure for monitoring As and heavy metals
and assessing human health implications. The study initially aimed at
establishing topsoil data to be used as baseline for long-term monitoring.
Overall total As concentration of superficial soils (0-5 cm), collected from
44 sampling sites randomly selected within a circular area up to 1.5 km
around the industrial district, was on average 33.8 ± 35.9 μg/g. This value,
is approximately 3 times higher than the European baseline and highlights
a general enrichment of topsoil As content. This is mainly attributable to
widespread geochemical anomalies characterizing Southern Tuscany and
to the historical mineral processing and smelting activities carried out in
the Scarlino area until the mid-90s. The highest As concentrations were
found in soils from sampling sites in the proximity of a pyrite ash dump,
where concentrations over 200 μg/g were reached. Average concentrations
(32.9 μg/g) from agricultural and grazing soils were also much higher
than the baseline for Italian agricultural lands (7.56 μg/g). Although soils
from urban sites generally showed the lowest As concentrations, average
As concentrations for the urban area (21.8 μg/g) remained over the screening values (20 μg/g) for contaminated soils set by the Italian regulatory
framework for residential areas. In this context, we used multi-element
analysis supported by techniques for monitoring atmospheric depositions
to improve estimation of exposure and related health risks arising from
the nearby industrial activities as well as to assess the relative contribution
of historical and present-day As sources in the Scarlino area
Assessing the impact on groundwater chemistry of an environmental restoration performed using industrial solid waste from TiO2 production
No full textA hydrogeochemical study was performed to assess the impact on groundwater chemistry of industrial solid waste (ISW) used for environmental restoration of a site degraded by past quarry activities in southern Tuscany (Italy). Water samples were collected from springs, piezometers and drains around and within this site where solid waste generated by industrial processes for the production of titanium dioxide (TiO2) has been disposed. Water samples were analysed for the physico-chemical parameters (temperature, pH, electrical conductivity, redox potential), major ions (Na, K, Ca, Mg, Cl, HCO3, SO4), trace elements (Fe, Mn, Ti, B) and isotopes (δ18O, δ2H, δ13C, 3H). The study area is characterised by a complex hydrogeological system consisting of groundwater belonging to four hydrochemical facies. The leachate of the stored ISW had high salinity and concentrations of major ions (mainly SO4, Cl, Na, Mg) and trace elements (Fe, Mn). The chemical features of leachate in the stored ISW are similar to those of water found in the ISW before disposal, primarily due by the reactions between the raw material (ilmenite slags) and reagents (e.g. sulphuric acid, seawater and limestone) during production of TiO2. The hydrochemical and hydrogeological findings suggested that: i) no change of chemistry due to leakage of the ISW leachate occurred in groundwater around the ISW disposal site; ii) dilution of the ISW leachate by meteoric waters was found in the landslide zone of the ISW disposal site; iii) mixing between the ISW leachate and groundwater [Na–HCO3(Cl) waters] probably took place under the ISW disposal site in the period immediately following a landslide event
Have the iceberg B15 affected the POPs bioaccumulation in the Ross Sea? The case of Trematomus bernacchii
No full textThe T. bernacchii is a Antarctic fish with a widespread distribution and high abundance in near-shore seawaters; thus it is considered a good bio-indicator for contamination study, assessment of changes in Antarctic ecosystem quality (1), and temporal trend evaluation.
In this study, levels of various POPs were evaluated in Trematomus bernacchii. POP concentrations determined in different years (data from the literature) were analyzed in order to investigate their concentration trends and the possible influence of iceberg melting
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
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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