122 research outputs found
Simultaneous determinations of zirconium, hafnium, yttrium and lanthanides in seawater according to a co-precipitation technique onto iron-hydroxide
Very low concentrations (pg mL 1 or sub-pg mL 1 level) along with the high salinity are the main
problems in determining trace metal contents in seawater. This problem is mainly considered for
investigations of naturally occurring YLOID (Y and Lanthanides) and Zr and Hf in order to provide precise
and accurate results. The inductively coupled plasma mass spectrometry (ICP-MS), both in high and low
resolution, offers many advantages including simultaneous analyses of all elements and their quantitative
determination with detection limits of the order of pg mL 1. However in the analysis of YLOID in
seawater, a better determination needs an efficient combination of ICP-MS measurement with a preconcentration
technique. To perform an ultra-trace analysis in seawater, we have validated an analytical
procedure involving an improved modified co-precipitation on iron hydroxides to ensure the simultaneous
quantitative recovery of YLOID, Zr and Hf contents with measurement by a quadrupole ICP-MS.
The validity of the method was assessed through a series of co-precipitation experiments and
estimation of several quality control parameters for method validation, namely working range and its
linearity, detection limit, quantification limit, precision and spike recoveries, and the methodological
blank choice, are introduced, evaluated and discussed. Analysis of NASS-6, is the first report on the latest
seawater reference material for YLOID, hafnium and zirconium
Distribution of YLOID in soil-grapevine system (Vitis vinifera L.) as tool for geographical characterization of agro-food products. A two years case study on different grafting combinations
The knowledge of a chemistry relationship between the soil and the agricultural products is an important tool for the quality assessment of food. We studied YLOID (Y, La and lanthanoids), recognized as very useful tracers due their coherent and predictable behavior, to trace and evaluate their distribution from soil to the grape in Vitis vinifera L. Because much of the world’s viticulture is based on grafting, and rootstocks have proved affect vine growth, yield, fruit and wine quality, we carried out experimental trials to analyse the YLOID distribution of two different red cultivars, grafted onto six different rootstocks, on the same soil. The YLOID amounts, the relationship Heavy vs Light YLOID and the pattern of YLOID were calculated. The results showed that the different grafting combinations were not able to induce significant differences in YLOID uptake from the soil maintaining the same fingerprint (with the exception of Eu)
Distribution of REEs in soil-citrus limon system(L.) Osbeck
The consumers have an increasing interest about food traceability with respect to safety, quality
and typicality issues. The knowledge of a chemistry relationship between the soil and the
agricultural products is an important tool for the quality assessment of food. Citrus Limon is the
most important fruit tree crop in the world and the detection of potential fraud could improve by
using tools linking the chemistry composition of this production to its typical growing area. This
study use rare earth elements (REEs) as geochemical tracers. The REEs are a set of 14 elements,
from lanthanum to lutetium that can be divided in light rare earth elements (LREEs), from La to Gd
and heavy rare earth elements (HREEs), from Tb to Lu. The REEs have recognized as very useful
tracers due to their generally coherent and predictable behaviour. The aim of the research is to
observe whether the fruits of various cultivars of citrus cultivated on the same soil and their
products (fruit and juice) reproduce the same distribution of REEs. Taking into account of our
previous works carried out on grapevine – soil system [1,2], we applied the same technique to
evaluate and trace the REEs distribution in soil– Citrus Limon fruits system. Sampling of soil and of
fruits was carried out in the CREA experimental farm located in Acireale (CT, Sicily) where are
present several Citrus Limon cultivars cultivated in Sicily. The REEs amount, the HREEs/LREEs
relations and their distribution in the fruit and citrus juice with respect to the own soil were
determined and calculated. The intriguing results obtained with a geochemical approach are the
first on the soil–Citrus Limon fruits system
Geochemical behaviour of rare earths in Vitis vinifera grafted onto different rootstocks and growing on several soils
The geochemical behaviour of lanthanides and yttrium(Rare Earth Elements, REEs) has been investigatedmainly
in geological systems where these elements represent the best proxies of processes involving the occurrence of
an interface between different media. This behaviour is assessed according to features recorded in sequences of
REE concentrations along the REE series normalised with respect to a reference material. In this study, the
geochemical behaviour of REE was investigated in different parts of Vitis vinifera specimens grown off-soil, on
soils of different nature and grafted onto several rootstocks in order to evaluate effects induced by these changes.
The results indicated that roots are the plant organs where REEs are preferentially concentrated, in particular
elements from Sm to Ho (middle REE, MREE) whereas Eu enrichments occur in aerial parts. The geochemical
behaviour of REE suggests that MREE enrichments in roots are due to preferential MREE interactions with
biological membranes or to surface complexation with newly formed phosphates. Eu-positive anomalies suggest
that Eu3+ can form stable organic complexes in place of Ca2+ in several biological processes in xylem fluids.
The possibility that Eu mobility in these fluids can be enhanced by its reductive speciation as Eu2+ cannot be
ruled out.
The assessment of the geochemical behaviour of REE according to the theory of the Tetrad Effect carried out
confirms that REEs coming fromsoil are scavenged onto root tissues or mineral surfaceswhereas their behaviour
in aerial parts of V. vinifera is driven by dissolved complexation
SUSTAINABLE PRODUCTION OF FENNEL AND DILL BY INTERCROPPING
Intercropping is claimed to be one of the most significant cropping techniques in sustainable agriculture, and much research and
many reviews attribute to its utilization a number of environmental benefits, from promoting land biodiversity to diversifying agricultural
outcome. In this sense, intercropping is thought to be a useful means of minimizing the risks of agricultural production in many environments,
including those typical of under-developed or marginal areas. In order to validate this hypothesis in a representative area of the semiarid
Mediterranean environment, we evaluated the possibility of growing dill and fennel, both belonging to the family Apiaceae, in temporary
intercropping. Our trial was performed in Sicily in 2000–01 and 2001–02; in the first year, fennel and dill were cultivated in a mixture using
a substitution scheme, whereas in 2001–02 we evaluated the bio-agronomical and chemical features of fennel alone. The biological efficiency
of the intercropping system was evaluated by using the Land Equivalent Ratio and the Competitive Ratio, and an estimate of the interaction
effects of both crops was performed by analyzing the major vegetative and yield traits of plants, along with the chemical profile of volatiles of
the fruits. Both in grain yield and in biomass yield, the most efficient cropping system was the intercropping ratio with a higher proportion
of fennel, in which the competitive ratio values calculated for dill reached 1.90 for grain and 2.59 for biomass. Our results also indicate that
the presence of dill exerted a clear stabilizing effect on fennel seed yield of the following year: whereas no difference in fennel seed yield was
detected from one year to the following on the previously intercropped plots, in the repeated pure stand a 50% yield reduction was recorded.
In the trial environment, the technique showed a good potential to improve the efficiency of resource utilization; further long-term experiments
will be necessary in order to demonstrate the application of such a technique to other medicinal and aromatic plant mixtures
Trace elements release from volcanic ashes to seawater. Natural concentrations in Central Mediterranean sea.
Distributions and concentrations of many minor and trace elements in epicontinental basins, as Mediterranean Sea,
are mainly driven to atmospheric fallout from surroundings. This mechanism supplies an estimated yearly flux of
about 1000 kg km-2 of terrigenous matter of different nature on the whole Mediterranean basin. Dissolution of
these materials and processes occurring at solid-liquid interface along the water column drive the distributions of
many trace elements as V, Cr, Mn, Co, Cu, and Pb with contents ranging from pmol l-1 (Co, Cd, Pb) to nmol l-1
scale in Mediterranean seawater, with some local differences in the basin.
The unwinding of an oceanographic cruise in the coastal waters of Ionian Sea during the Etna’s eruptive activity
in summer 2001 led to the almost unique chance to test the effects of large delivery of volcanic ash to a coastal sea
water system through the analyses of distribution of selected trace elements along several seawater columns. The
collection of these waters and their analyses about V, Cr, Mn, Co, Cu, and Pb contents evidenced trace element
concentrations were always higher (about 1 order of magnitude at least) than those measured concentrations in
the recent past in Mediterranean seawater, apart from Pb. Progressive increase of concentrations of some elements
with depth, sometimes changing in a “conservative” behaviour without any clear reason and the observed higher
concentrations required an investigation about interaction processes occurring at solid-liquid interface between
volcanic ash and seawater along water columns.
This investigation involving kinetic evaluation of trace element leaching to seawater, was carried out during a
6 months time period under laboratory conditions. X-ray investigations, SEM-EDS observations and analyses
on freshly-erupted volcanic ash evidenced formation of alteration clay minerals onto glass fraction surfaces.
Chemical analyses carried out on coexisting liquid phase demonstrated that trace element leaching occurs through
a first quick followed by a slow second step that attaints to an apparent equilibrium after 6 months. Amplitude of
kinetic rate constant measured for SiO2 release during the first step and behaviour of Ti/Si and Cr/Si rations in
primary volcanic minerals, glass fraction and leaching solutions during the first 1 month stage of the experimental
interaction allowed to demonstrate that trace element release mainly occurs from glassy materials and Ti-rich
magnetite
Discrimination between effects induced by microbial activity and water-rock interactions under hydrothermal conditions according to REE behaviour
Rare earth elements (REE) were investigated in siliceous stromatolites forming in the Specchio di Venere Lake on Pantelleria Island. Chondrite-normalised patterns show significant La enrichments and Eu depletions suggesting that fluids involved in stromatolite growth experienced strong rock-water interactions under hydrothermal conditions. At the same time, enrichments in heavy REE (HREE) with respect to intermediate REE (MREE) suggest that hydrothermal fluids interacted with microbial mats during deposition of the stromatolites. The above-mentioned features suggest that rock-water interactions and bacterial activity were simultaneously recorded in the REE patterns of stromatolites, and can be discriminated in terms of amplitudes of the La anomaly, and the HREE/MREE ratio
Characterization of the Etna volcanic emissions through an active biomonitoring technique (moss-bags): Part 1 – Major and trace element composition
Active biomonitoring using moss-bags was applied to an active volcanic environment for the first time. Bioaccumulation originating from atmospheric deposition was evaluated by exposing mixtures of washed and air-dried mosses (Sphagnum species) at 24 sites on Mt. Etna volcano (Italy). Concentrations of major and a large suite of trace elements were analysed by inductively coupled mass and optical spectrometry (ICP-MS and ICP-OES) after total acid digestion. Of the 49 elements analysed those which closely reflect summit volcanic emissions were S, Tl, Bi, Se, Cd, As, Cu, B, Na, Fe, Al. Enrichment factors and cluster analysis allowed clear distinction between volcanogenic, geogenic and anthropogenic inputs that affect the local atmospheric deposition. This study demonstrates that active biomonitoring with moss-bags is a suitable and robust technique for implementing inexpensive monitoring in scarcely accessible and harsh volcanic environments, giving time-averaged quantitative results of the local exposure to volcanic emissions. This task is especially important in the study area because the summit area of Mt. Etna is visited by nearly one hundred thousand tourists each year who are exposed to potentially harmful volcanic emissions
Alteration effects of volcanic ash in seawater: Anomalous Y/Ho ratios in coastal waters of the Central Mediterranean sea
This paper presents the results of a study based on data collected during the oceanographic cruise ANSIC 2001 carried out in the Ionian Sea during the explosive activity of Mount Etna in the summer of 2001. Anomalous low values of Y/Ho ratios in seawater suggest extensive scavenging processes on the surfaces of smectitic alteration products, with Y and Ho fractionation controlled by the differences in their electronic configurations and behaviour during solution/surface complexation equilibria. These processes can also be traced through the presence of significant tetrad effects recorded in the chondrite-normalised Rare Earth Elements and Yttrium (YREEs) patterns of suspended particulate matter. This suggests that the preferential Y scavenging from seawater is due to the formation of inner-sphere complexes with OH- groups on montmorillonite crystal surfaces. The preliminary results of kinetic experiments of YREE released from volcanic ash to coexisting seawater, and the related effects on Y/Ho ratios and Ce anomalies, are consistent with the fractionation of Light Rare Earth Elements (LREEs) with respect to Heavy Rare Earth Elements (HREEs) observed in dissolved phase. They suggest a behaviour of Y similar to that reported for LREEs, particularly for Ce and Pr. © 2007 Elsevier Ltd. All rights reserved
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