The High Agri Valley (southern Italy) is one of the largest intermontane basin of the southern Apennines affected by intensive agricultural and industrial activities. The study of groundwater ...chemical features provides much important information useful in water resource management. In this study, hydrogeochemical investigations coupled with multivariate statistics, saturation indices, and stable isotope composition (δD and δ18O) were conducted in the High Agri Valley to determine the chemical composition of groundwater and to define the geogenic and anthropogenic influences on groundwater quality. Twenty-four sampling point ( including well and spring waters) have been examined. The isotopic data revealed that groundwater has a meteoric origin. Well waters, located on recent alluvial-lacustrine deposits in shallow porous aquifers at the valley floor, are influenced by seasonal rainfall events and show shallow circuits; conversely, spring waters from fissured and/or karstified aquifers are probably associated to deeper and longer hydrogeological circuits. The R-mode factor analysis shows that three factors explain 94% of the total variance, and F1 represents the combined effect of dolomite and silicate dissolution to explain most water chemistry. In addition, very low contents of trace elements were detected, and their distribution was principally related to natural input. Only two well waters, used for irrigation use, show critical issue for NO3- concentrations, whose values are linked to agricultural activities. Groundwater quality strongly affects the management of water resources, as well as their suitability for domestic, agricultural, and industrial uses. Overall, our results were considered fulfilling the requirements for the inorganic component of the Water Framework Directive and Italian legislation for drinking purposes. The water quality for irrigation is from “good to permissible” to “excellent to good” although salinity and relatively high content of Mg2+ can occasionally be critical.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A PM1 geochemical and mineralogical study using Scanning Electron Microscopy (SEM) was performed on a pilot site in the Agri Valley which is close to the oil pre-treatment plant (C.O.V.A) of Europe's ...largest on-shore hydrocarbon reservoir. The study identified PM1 geochemical and mineralogical characters in the period before, during and immediately after a burning torch flare event. The finer fraction (DFe < 0.7 µm) consisted mainly of secondary particles and soot. In the coarser fraction (DFe≥0.7 µm), natural particles originating from crustal erosion and soot were abundant. Fine quartz particles and lower Al / Si ratios are markers for desert dust origin, proving that a Saharan dust episode which occurred during the observation period played a significant role in supplying geogenic aerosol components to the PM1. Largest amounts of ≥ 0.7 µm fraction particles observed on the day of flare event may be due to a greater supply of Saharan geogenic particles. Soot had been significantly increasing long before the flare event, suggesting that this increase is also related to other causes, although we cannot exclude a contribution from flaring. S-rich aerosol consisted mainly of mixed particles originating from deposition and heterogeneous nucleation of secondary sulfates on mineral dust. Only-S particles were identified in the ≥ 0.7 µm fraction following the flare event. These particles may be indicators of larger amounts of sulphur in the atmosphere.
Hereby, it is considered the literature concerning the mobility of chemical elements from healing clays to the human body, including
in vitro and
in vivo studies with specific aim. Two main types of ...clay administration for healing uses are topical applications (usually in spa centres) and ingestion (either in a voluntary or unintentional way). The mechanism of element mobility is very different for the two applications. The topical use mainly involve soluble and exchangeable chemical elements, whereas the ingestion of clays is more effective due to great aggressive conditions into the stomach.
Some poorly known implications of clay uses are mentioned, such as the effects of organic compounds in the transdermal migration of elements and the effective simulation of the digestion, that is in balance between chemical leaching and adsorptive effect of clays.
The capacity of clays to remove or attenuate the contamination of aflatoxin M1 in bovine milk was studied, while considering the effects of these clays on the nutritional properties of the milk (in ...terms of protein, fat and lactose). To make the experimental results transferable to practical use, only clays available from the market were tested, and a very simple clay–milk interaction procedure was used. A preliminary test was developed to compare the adsorption behaviour of two clays, a kaolin and a bentonite, at variable clay–milk ratios and to trace the variations in the protein, fat and lactose contents. Then, only bentonites were selected for additional study.
The detoxification capacity of the bentonites used was variable but still very efficient: contaminated bovine milk (up to approximately 80ng/L) was purified to safe levels (50ng/L for adults and 25ng/L for lactants) with moderate alteration of the nutritional properties of the milk. Moreover, the amount of bentonite residue in the purified milk was very low (0.4%). The kaolin was less adsorptive than the bentonite but still able to decrease the aflatoxin M1 within legal limits and was better at maintaining the nutritional properties of the milk. The protein is more sensitive to clay adsorption than are fat and lactose, and there was a decrease in protein in the treated milk with increases in the ratio of clay to milk.
Among the studied samples, a saponite-rich bentonite showed the highest adsorbent capacity, in agreement with theoretical considerations regarding higher cell surface areas (available for AFM1) and higher surface hydrophobicity of saponite. Analyses of isothermal adsorption in water using the two more effective bentonites were also performed.
The data collected indicate an effective and safe use of clays in the detoxification of milk (and dairy products) contaminated with aflatoxin M1.
•Interaction of kaolinite and smectite with aflatoxin M1•Nutritional properties of milk after interaction with clay minerals•Higher cell surface and hydrophobicity of smectite enhance AFM1 adsorption.•Adsorption of organic contaminants from bovine milk•Isothermal adsorption of AFM1 on smectite in water
Silty sands and clayey silts taken from a landslide in the Agri Valley have been analysed in order to study the role of sediment composition in the slope stability and the development of a slip zone. ...A geognostic hole was used to collect samples and monitor movements. A slip zone at a depth of about 14 m was identified. Compositional and physical–mechanical characterisation of samples was carried out. Some compositional characters, such as a 32–2 μm grain-size fraction, clay mineral content, cation exchange capacity and total nitrogen, increase in the slip zone. Some correlations have been found between geotechnical properties (residual shear strength and residual friction angle) and the same compositional characters, which can therefore be considered possible factors influencing slope stability.
Weathering of outcrops of ultramafic rocks (remnants of ancient oceanic crust) is a source of biologically toxic trace elements, particularly first row transition elements. The Cr and Ni ...concentrations of serpentinite and metabasite outcrops in the northern sector of the Pollino massif (Lucanian Apennines, southern Italy) are hundreds of orders of magnitude higher than those of the upper continental crust. In this region, exposed intermediate to lower crustal rocks are significantly enriched in Ni, Cr, and V relative to the average upper continental crust. We evaluate the levels and distributions of trace elements of environmental concern, including Cr (as total dissolved Cr and Cr(VI)), V, Mn, Fe, Ni, Cu, Zn, As, Pb, and U, in spring waters from the northern sector of the Pollino massif.
The major solutes in the spring waters from this region are Mg-HCO3 and Ca-HCO3. The Mg-HCO3 type waters are produced mainly through the interaction of meteoric waters with serpentinites, whereas the Ca-HCO3 type waters are produced through the interaction of meteoric waters with Ca-rich rocks (i.e., carbonate rocks, calc-schists, and metabasites). Thermodynamic evaluation indicates that in the MgO–SiO2–Al2O3–H2O system, waters flowing in serpentinites fall in the kaolinite field, close to the kaolinite–Mg-vermiculite phase boundary. This result arises because kaolinite is a relatively early reaction product, which is consumed to produce Mg-vermiculite and further Mg-saponite. In the CaO–SiO2–Al2O3–H2O system, Ca-HCO3 type waters fall either in the field of gibbsite or kaolinite, depending on dissolved silica.
Chromium (VI) contamination associated with local mineralogy and with maximum admissible concentration >5μgL−1 was observed for nine springs (both Mg-HCO3 and Ca-HCO3 type waters). The Cr(VI)-rich Ca-HCO3 springs are not located in serpentinites. However, some of these waters likely acquire their high Cr levels from interacting with serpentinite clasts, as in the case of springs flowing through conglomerates. In addition, Cr(VI) contamination is not limited to waters interacting with serpentinites or serpentinite clasts, because in one case weathering of garnet-rich gneiss is responsible for the release of significant amounts of Cr(VI) in solution.
Finally, studies are needed to address the potential health risks associated with the observed high concentrations of Cr(VI) in waters from the Pollino massif area. A mode-of-action analysis is needed to evaluate adverse health risks associated with exposure to Cr(VI) in drinking water, especially as Cr contamination is not limited to springs flowing through serpentinites.
► Serpentinite, metabasite, and garnet-rich gneiss in the Pollino massif, Italy. ► Distributions of Cr(VI) in spring waters. ► Springs waters in the Pollino massif are either Mg-HCO3 or Ca-HCO3. ► Cr(VI) contamination in springs of both Mg-HCO3 and Ca-HCO3 type. ► Contamination is not confined to springs which flow through serpentinites.
A landslide, to the west of Montemurro (a small village in southern Italy), has recently caused damage to buildings and other infrastructure in an urbanized area; as a result the development of new ...economic activities has been prohibited. The landslide phenomenon started in the last century and has been studied since the 1990s using classical geotechnical methods; however the sliding body continues to move. This paper presents the results of a study carried out using field surveys, geognostic investigations and TDR (time domain reflectometry) measurements in order to reconstruct the stratigraphy of the sediments involved and to further understand the geological and geomorphological context of the slope. This study is part of a larger multidisciplinary project, the results of which will also be presented in this paper. The landslide (rotational slide in the upper sector, developing into a translational slide in the lower part) affects Quaternary continental clastic deposits resting on a bedrock formed by Tertiary siliciclastic sediments of the Gorgoglione Flysch. TDR measurements did not show any significant movement during the period monitored (January 2013–January 2014). Slip zone geometries were hypothesized using inclinometric measurements taken from previous studies, stratigraphic data and geomorphological interpretations of topographic scarps. Feedback from monitoring will confirm this hypothesis.
In-vitro experiments have been developed to ascertain whether pelotherapy applications involve the transfer of chemical elements from the healing mud to the human body, across the skin. All the ...materials used for therapy (raw clay, mineral water and healing mud obtained after maturation) have been characterised from different points of view (mineralogy, chemistry, exchange properties, radioactivity, grain size and microbiology) in order to get an accurate knowledge of the natural media used for therapy and to follow the development of maturation in the spa centre.
A polymineralic silty clay with rather a common mineralogical and chemical composition is used; the mud is matured in a very saline mineral water, of marine origin, for 5 months. Under these conditions the maturation process increases the dispersion of clay particles and allows cation exchange between clays and water, whereas neither microbiological nor mineralogical changes are detectable. In absence of the biologic indicators of mud maturity, the equilibration of clay with mineral water represents an objective quantitative criterion.
In-vitro tests have been carried out by using the Franz-type diffusion cells, which show that the transfer of chemical elements across the skin is very well-developed, and also involving many essential or possibly essential elements. The amounts of chemical elements transferred were compared with toxicological guidelines and with world-wide daily requirement models.
No concerns appear from the data, whereas a significant supply of some elements results from a typical application of thermal mud (20 min, full body). The elements which have been considered in order to represent a significant supply are Li, Sr, B, I, Rb, Br, Ba, Na, Cl, Se and Ca, some of these are essential nutrients. The biological effects of the main elements are briefly discussed.
The work deals the interactions between two commercial clays, a bentonite and a kaolin, and an iron-salicylate complex. Adsorption experiments were accomplished using a water solution containing ...Fe(III) 0.0176 M and salicylic acid 0.0253 M. Natural and treated clay samples were characterized by chemical analyses, powder X-ray diffraction, thermal analyses. The time dependence of salicylic acid adsorption by bentonite follows first-order kinetics, with respect to the percentage of salicylic acid adsorbed, in the first 12 h; afterwards the reaction slows down. The reaction is completely exhausted after 2 days and during the next 4 days the concentration of salicylic acid in bentonite does not change from its asymptotic value of 8.0%. The adsorption kinetics of salicylic acid by kaolin highlights a slow adsorption beginning after the fourth day of treatment, and finished after 19 days. The amount of salicylic acid adsorbed was 5.5% of the final complex. The release of salicylic acid adsorbed by bentonite and kaolin was tested in 0.2 N solutions of Na
+, K
+, Mg
2+, and Ca
2+. Salicylic acid release rates from Fe(III)-salicylate-containing bentonite were also measured through cellulose acetate membranes by means of Franz-type diffusion cells: an initial slow release of salicylic acid was followed by a fast release phase; after 23 h the concentration of salicylic acid released can be considered constant and the drug desorbed was 1.4% of the amount adsorbed by the bentonite. Even if the desorbed amount of salicylic acid is not very high, the bentonite–salicylate complex could be suitable for an application by gradual release.
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