1,721,205 research outputs found
Caratteri sedimentologici e geochimici dei sedimenti marini in alcuni settori dei mari italiani
Full text linkA detailed study of surface samples and sediment cores from some marine areas surrounding the Italian peninsula was carried out by means different analyses. In particular, the activity was addressed to study some key sectors in the central-southern Adriatic Sea and the deep basins of the Sicily Channel (Pantelleria, Linosa and Malta basins). Different approaches were used, mainly represented by geochemical analyses, grain size analyses and more complex other ones, such as the statistical Q Mode Factor Analyses developed to integrate the results of GIS elaboration for a better interpretation.
Grain size and geochemical composition of sediments of a sedimentary succession may contribute to recognize different signals, which may be important for geological, environmental and paleo-environment
reconstruction. When integrated with other information (mineralogy, paleontological content, etc.) these signals can allow reconstructing a general framework of the environmental dynamics of a certain study area.
Based on this approach a representative map of the sediment distribution of central-southern Adriatic Sea has been realized to include also sediment texture and geochemical composition. Moreover, sediment source areas were defined for both the studied Adriatic sector and the deep basins of the Sicily Channel. The above
mentioned results represent only some of the results obtained and therefore the research can be developed further. The evolution of the studied areas represents a key example for the study of recent sedimentary
successions or older basin successions in other areas.
The analytical results obtained are particularly significant also for environmental analyses, as demonstrated by the studies concerning the amount and distribution of mercury in the sediments of the central-southern
Adriatic area and the ecological quality status of marine benthic system in the Manfredonia Gulf (southern Adriatic Sea
Geochemical mapping based on geological units: A case study from the Marnoso-arenacea formation (Northern Apennines, Italy)
No full textGeochemical maps can provide us with much information on geology, earth surface processes and anthropogenic pressure and are valuable tools for ore prospecting and land management. Stream sediments represent an integral of the various possible sources of sediments upstream from the sampling point therefore there can be multiple signal sources but generally the prevailing signal source is the one related to bedrock geology. Stream sediments collected from active second-order channels including singular geological units, were selected in order to determine the geochemical characteristics of each unit. The aim of this study was to analyze their potential for using them to integrate geological interpretation and produce a geologically-oriented geochemical map. From the 770 samples collected for a regional geochemical mapping program, we selected 149 samples whose catchment basin included only one of the members recognized within the Marnoso-arenacea formation. This middle-upper Miocene (Langhian-Tortonian) turbiditic unit forms the backbone of the Romagna Apennines and has been subdivided into 14 members according to age and lithostratigraphic criteria. The results indicate that there are marked differences in the composition of the members of the Marnoso arenecea formation which indicate the provenance of the sediment and the palaeogeographic evolution of the units. By means of univariate and multivariate statistical analyses (Factor analyzes) two main types of sediment compositions are identified: Tortonian members are characterized by sialic coarse grain-sediments while the Langhian-Serravallian members are richer in carbonate fraction, slightly enriched in a mafic contribution. This study elaborated the geochemical data from a geological point of view by integrating the information available in literature to spatially extend the interpretation based on limited site observation as for petrographic studies. In general, the geochemical map based on a geological unit could be a useful tool for carrying out the geological reconstruction of a complex area
Geochemical characterization and rare earth elements anomalies in surface- and groundwaters of the Romagna area (Italy)
No full textHighly industrialized and urbanized areas can be affected by microcontamination due to the inefficiency of wastewater treatment plants to remove micropollutants from effluents, with the consequence of reversing them totally or only partially undegraded in the environment. Gd, one of the rare earth elements (REE) group, can be considered as a tracer of wastewaster effluents contamination. It is commonly used as contrast agent in magnetic resonance imaging and it can be detected in hospital and wastewater discharges. In this study, surface- and groundwater quality of the Romagna area was assessed, with a particular focus on REE content in water. The efficiency of two drinking water treatment plants in removing microcontamination was also evaluated comparing REE concentrations at the entrance and exit of the plants. Chemical analyses on a large set of trace elements, as well as major ion content, were performed to geochemically characterize surface- and groundwaters and to investigate possible relations with REEs. The study revealed water chemistry of both surface- and groundwaters mainly controlled by carbonates and clay minerals contribution. As regards REEs, Gd contamination was detected only in surface waters in the northern part of the study area; in the Lamone river, this contamination was accompanied by the detection of La anomalies, reflecting a contaminated environment. The two drinking water treatment plants showed that common water treatment techniques are often inefficient to remove microcontamination
Geochemical characterization of surface sediments from the northern Adriatic wetlands around the Po River delta. Part II: aqua regia results
No full textSediment characterization is crucial when assessing environmental quality of aquatic systems. In a previous study, we assessed the geochemical composition of surface sediments of several wetlands within the historical Po deltaic system by using X-ray fluorescence, and we evaluated the anthropogenic influence on the metal levels comparing data with background and calculating enrichment indexes. In the area, geochemical information is poor and quality standard levels for sediments are still lacking in regulation frameworks. As a further investigation of the previous study, we investigated the pseudo-total concentrations, after aqua regia digestion, of Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Hg, K, La, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Pd, Pt, Rb, S, Sb, Sc, Se, Sn, Sr, Th, Ti, Tl, U, V, Y, Zn, and Zr in sediments from 4 coastal wetlands belonging to the historical Po deltaic system (NE Italy) (Valli di Rosolina, Valle Bertuzzi, Valli di Comacchio, and Pialassa della Baiona). The aims were (1) to study relationships among elements by applying multivariate statistics, (2) to evaluate the extractability degree with respect to the total contents, and (3) to better understand the environmental relevance of the trace elements in the study area by comparing pseudo-total contents with background concentrations, screening values provided by Italian legislation and reference values reported in environmental guidelines and recent scientific literature. According to the results of this study: 1) shellfishing is legal, and also illegally practiced, in the site the most affected by heavy metal pollution; 2) part of the Pb enrichments in most sites could be originated by lead shot in the sediment; and 3) habitat and species conservation in these investigated Special Protected areas should consider geochemical aspects
Distribution and partition of endocrine disrupting compounds in water and sediment: Case study of the Romagna area (North Italy)
No full textThe study aimed to assess the occurrence and partitioning of estrogens (ß-estradiol, E2; estrone, E1; 17α-ethinylestradiol, EE2), phenolic compounds (nonylphenol, NP; octylphenol, OP; bisphenol A, BPA) and perfluorinated compounds (perfluorooctanoic acid, PFOA; perfluorooctane sulfonate, PFOS) in waters and sediments of the main rivers and the coastal lagoon of Pialassa Baiona, in the north-eastern part of Italy. Overall, water samples showed a wide distribution of the three classes of compounds in the study area, with the exception of estrogens which recorded only some local detections, at concentrations <10 ng/L. Sediments were found to be affected only by contamination of phenolic chemicals, namely BPA and NP, whereas perfluorinated compounds were almost undetected (<LOQ) in all sampling stations. Estrogens displayed only some local measurements in sediments, in accordance with water results. BPA and NP in sediments were highly correlated with organic carbon content and were dependent on the grain size of sediments. The greatest partition coefficients were registered in the coastal lagoon, proving that salinity enhances phenolic adsorption onto sediments. Globally, based on estrogenicity data taken from literature, the current environmental concentrations of the different chemicals in the study area are not likely to cause adverse estrogenic effects on the aquatic biota
Assessment of metal accumulation capacity of Dittrichia viscosa (L.) Greuter in two different Italian mine areas for contaminated soils remediation
No full textThe study aimed at assessing the capacity of Dittrichia viscosa (L.) Greuter to absorb and accumulate in its tissues some
potentially harmful elements (PHEs), as Cd, Cu, Fe, Ni, Pb and Zn, in order to verify its possible use as phytoremediation
in polluted mine soils. Plants from two different Italian mine areas, Montevecchio and Libiola, were considered
and compared with plants from unpolluted areas. In each site (n = 21), both rhizospheric soil materials and D. viscosa
plants were sampled, suitably prepared and analyzed. Soil samples were examined for both total composition (XRF) and
bioavailable fractions (DTPA-extraction). Dittrichia viscosa roots, stems and leaves were analyzed separately to quantify
the metal presence in the different plant parts. The root/soil ratio values calculated on the basis of the total soil concentrations,
displayed a generally scarce capacity of D. viscosa to absorb soils PHEs, especially those more concentrated in the
substrata. Concerning the root/soil ratio calculated on the basis of DTPA-extractable soil metals, values displayed instead
a greater capacity of D. viscosa to absorb metals in the roots thus behaving as a potential phytostabilization plant in both
mine areas.
Regarding the leaf/root ratio, this species also displayed a greater capacity, in sub alkaline mine areas, to shift PHEs
from roots to aboveground tissues, along with Ca transfer, revealing interesting characteristics for phytoextraction. In
sub acid mine areas, this tendency was instead weaker and PHEs tended to be accumulated in all plant parts. Dittrichia
viscosa seems to be appropriate for mine soil stabilization in both sub acid and sub alkaline environments and also for
phytoextraction in the latter
Trend of Heavy Metal Release According to Forecasted Climate Change in the Po Delta
No full textThe low-lying coastal areas, and especially the delta areas are prone to saltwater intrusion due to sea level rise, which may lead to a loss of ecosystem services brought about by salinization of already limited freshwater reserves. Despite the acknowledged importance of climate change impacts and land use practices on water resources availability, there is still a lack of studies on the issue of climate change induced alteration of water quality. To understand the hydrogeochemical processes occurring within the shallow groundwater system of the Po River delta (Italy), the contribution of local water-sediment interaction and the anthropogenic influence on groundwater quality were quantified. High-resolution multi-level sampling was used to capture chemical gradients within the aquifer. Data were employed to calibrate a density-dependent multicomponent reactive transport model implemented with PHT3D code along a flow line. The reactive network accounted for redox driven organic matter oxidation and cation exchange. Finally, a series of numerical scenarios were run following the projection of IPCC 2014 on sea level rise and climate change. Results of the predictive model highlight an increase of arsenic and lead in the shallow portion of the aquifer, drained by the reclamation network. The increase of heavy metals export toward surface waters could be of serious concern, since the drainage network operates also for irrigation purposes. Thus, the surface water quality could be negatively affected by climate change
Sediment quality of the Ridracoli fresh water reservoir in Italy: Insights from aqua regia digestion and sequential extractions
No full textThe inter-element relationships and the forms in which metals exist strongly influence their mobility and, in turn, have a signature on the environment and human health. Located in the northern Apennines within the Emilia-Romagna re-gion, the Ridracoli artificial lake is one of Italy's most important reservoirs that provides drinking water for about one million people. This work characterized the reservoir sediments by ICP-MS after aqua regia digestion (ARD), compar-ing the limits by law to assess environmental compliance and XRF data from the same sample-set taken as total con-centrations. The Degree of Extraction (DE) from pseudo-total concentrations of ARD analysis allows assessing elements mobility and the associated environmental risk. Principal Component Analysis (PCA) on the obtained data helped to investigate inter-element relationships better; for example, we observed carbonate-sourced sediments, many trace elements (e.g., Ni, Zn) linked to FeMn oxyhydroxides, the importance of the grain size in elements distri-bution, and the central role of the organic matter in element partitioning. In addition, a Sequential Extraction Proce-dure (SEP) was applied to the sediment samples to understand the partitioning of many analytes, including Potentially Harmful Elements (PHE) such as Fe, Mn, Cu, Cr, Ni, Pb, and Zn. The results indicated that the most easily mobilized forms were predominant in the area near the dam, in correspondence to sediments affected by the formation of a seasonal anoxic layer
Occurrence and distribution of six selected endocrine disrupting compounds in surface- and groundwaters of the Romagna area (North Italy)
No full textEndocrine disrupting compounds (EDCs) are a wide group of contaminants of emerging concern known to be harmful for organisms. The aim of the study was to assess the occurrence and distribution of six EDCs (estroneâE1, Ã-estradiolâE2, 17α-ethinylestradiolâEE2, bisphenol AâBPA, perfluooctanoic acidâPFOA, perfluorooctane sulfonateâPFOS) in the Apenninic rivers and groundwaters of the Romagna area (North of Italy). Groundwaters were unaffected by EDC contamination, while all classes of compounds were detected at concentrations above the method quantification limit (MQL) in the majority of the river bodies. In detail, PFOA and PFOS concentrations varied between <MQL and 17.7 ng/l (PFOA) and between <MQL and 5.5 ng/l (PFOS), and their occurrence in the aquatic compartment was related to the discharge of wastewater treatment plant effluents. Concerning estrogens, EE2 was below the MQL in all samples, whereas E1 and E2 reached concentrations up to 39.7 ng/l (E2) and 28 ng/l (E1) in surface waters. The highest estrogen values were registered in those areas where livestock and farming are the main activities, indicating a close relation between these activities and estrogen release into the aquatic compartment. BPA (<MQLâ171.3 ng/l) distribution in river waters did not show any correlation with a specific anthropic activity; a mixture of sources of contamination (e.g., industries of food packaging and plastic production) is rather responsible for its detection in river bodies. Overall, the northern part of the Romagna area showed a higher contamination by EDCs, in contrast with the southern part, which was almost unaffected by this kind of microcontamination
The influence of flow-through saline gravel pit lakes on the hydrologic budget and hydrochemistry of a Mediterranean drainage basin
Full text linkFlow-through brackish gravel pit lakes near the Adriatic Coast of Emilia Romagna (Italy) in the Mediterranean have a large influence on the hydrologic budget of the watershed. Strong evaporation in combination with intense drainage of the low lying basins enhances groundwater inflow into the lake. Precipitation falling on the lakes is mixed with brackish/saline lake water causing the loss of freshwater. The gravel pit lakes are characterized by a high salinity (TDS = 4.6-12.3 g L"1) and high pH (8.5). Stable isotope data show that gravel pit lake water is fed by groundwater which is a mix of Apennine River water and (Holocene) Adriatic Seawater, subsequently enriched by evaporation. The slope of the local evaporation line is 5.4. Conservative tracer and water budget modeling shows that the final Cl concentration depends strongly on the ratio of evaporation to total inflow. Increasing drainage to compensate for sea level rise, subsidence or intense precipitation would enhance ground water flow into the lake and decrease Cl concentration while increasing evaporation would increase Cl concentration. Groundwater rich in dissolved trace elements flows into the gravel pit lakes that contains water with a higher pH and dissolved oxygen. Pit lake water remains enriched in some elements (e.g., Ba, Mo, Sb) and depleted in others (e.g., Fe, Ca, Zn, SO4) with respect to groundwater composition. The gravel pit lakes show limited eutrophication but the water quality should be monitored for trace elements (e.g., As) if they are to be used for recreational purposes.</p
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