Barbara Faccini

Water contents of pyroxenes in intraplate lithospheric mantle

Water contents of clinopyroxene and orthopyroxene in mantle peridotites from various xenolith occurrences in intraplate settings (both oceanic and continental) were determined by Fourier Transform Infrared Spectroscopy (FTIR). Samples from the following localities were studied: Sal Island (Cape Verde Archipelago); Baker Rocks and Greene Point (Northern Victoria Land, Antarctica); Panshishan and Lianshan (Subei Basin, Eastern China). They represent well-known localities where detailed petrographical and geochemical studies have already been carried out or areas which are currently under investigation. The water incorporated in these pyroxenes is low (cpx, 37–399 ppm; opx, 9–166 ppm) or very low (as in Greene Point, Antarctica; cpx, 5–16 ppm; opx, 9–16 ppm). Within each population there is no clear correlation with melting parameters such as MgO contents in any single mineral. Results are compared with the available literature data on water contents in mantle pyroxenes, which include peridotites from on-craton (hosted by kimberlitic-type magmas) and off-craton (hosted by alkaline basic magmas), as well as subarc mantle settings. The “relatively dry” (cpx, 140–528 ppm; opx, 38–280 ppm) sub-arc mantle xenoliths (Peslier et al. , 2002) are shown to be wetter than the intraplate (off-craton) xenoliths. Cratonic mantle pyroxenes are only represented by a few determinations on garnet peridotites and eclogite from Kaapvaal and Colorado Plateau. They record the highest water contents (cpx, 342–1012 ppm; opx, 180–491 ppm) so far measured in mantle pyroxenes from various tectonic settings. Despite the limited data set, the indication that the cratonic mantle is strongly hydrated is compelling. Rehydration of cratonic mantle may be related to plate subduction ( i.e. , Colorado Plateau) or alternatively to metasomatic enrichment ( i.e. , Kaapvaal Craton). However, assuming that the water content was initially very low, metasomatic events in intraplate settings, similar to those presented here, would not be able to produce a significant increase in pyroxenes water content. According to our own data and those reported in the literature, it appears that substantial rehydration may instead occur at convergent plate margins.

Reclamation influence and background geochemistry of neutral saline soils in the Po River Delta Plain (Northern Italy)

Reclaimed neutral saline sulphate soils constitute a large part of the eastern part of Po Plain lowlands, where intensive agricultural activities take place. The knowledge of their geochemical features is essential to develop the best management practices capable to preserve this threatened environment. With this aim, three boreholes were drilled in an agricultural field and a typical reclaimed soil profile has been characterized for major and trace element, pH, electrical conductivity, redox conditions and water-soluble anions and ammonium. Statistical analysis (cluster analysis and principal component analysis) has been used to understand the relationship between elements and grain size. The soil profile is characterized by high salinity and high organic matter contents responsible for high chloride, sulphate, and ammonium concentrations. Heavy metal content is naturally high, since Po Plain sediments are the result of ultramafic rocks erosion; in addition, organic matter tends to concentrate heavy metals by adsorption, mainly in peaty horizons. As a consequence of chemical and zootechnical fertilization, high NO3− contents have been found in the top soil, thus enhancing the risk of nitrate discharge in the water system, especially in relation to extreme climatic events.

Abnormal trace element concentrations in a shallow aquifer belonging to saline reclaimed environments, Codigoro (Italy)

Geogenic trace element (TE) contamination is an upcoming concern. The present study reports the temporal and spatial variation of major ions and TEs in a shallow unconfined aquifer belonging to a complex marsh saline environment reclaimed in modern age and intensively cultivated. The use of intensive depth profiles in five different locations gave insights into groundwater and sediment matrix interactions. Data indicate that the dominant factor involved in determining the spatial variability of TE is the sediment–water interaction, while the temporal variation of TE is due to the organic matter content and to the water table oscillation, which in turn drive the groundwater redox status and the mobilization of some inorganic microconstituents, such as Fe and Mn. Despite that the anthropogenic input of TEs in groundwater from fertilizer sources cannot be undoubtedly ruled out, given the elevated TE background concentrations, the combined use of high-resolution sediment profiles, seasonal groundwater sampling and end-member analyses is a promising procedure to distinguish between anthropogenic metal contamination and geogenic contribution in reclaimed deltaic environments. Finally, this study underlines the need of having a dense piezometer network and to perform several monitoring campaigns to ensure that the temporal and spatial variability could be correctly represented and background values of TE confidently determined.

Ammonium-exchanged zeolitite preparation for agricultural uses: from laboratory tests to large-scale application in ZeoLIFE project prototype

Water nitrate pollution is one of the biggest environmental issues in all those Countries whose economy is largely based on agriculture. Limiting the nitrogen compound input in the soil-water-air system requires the development of innovative and sustainable farming practices, allowing the reduction of fertilizer amounts but assuring good yields. This study describes the optimization of the uptake of swine manure-derived ammonium by zeolitite, as one of the first result of ZeoLIFE project (“Water pollution reduction and water saving using a natural zeolitite cycle”, LIFE+10 ENV/IT/000321). Natural Italian chabasite-bearing zeolitite has been mixed with swine manure at different zeolitite/manure ratios and operative conditions, in a series of laboratory batch tests. The effective NH 4 + -uptake has been measured with different methods, in order to validate the best criteria to reproduce the cation exchange reaction at large scale in a prototype, specifically conceived and built for the industrial production of NH 4 + -charged zeolitite. Experimental results indicate that the best conditions for maximum ammonium uptake are matched using a zeolitite/manure ratio of 25 g/L, a stirring time of 45 minutes and a resting time of 12 hours. These experimental conditions, when operatively applied at the prototype, always led to a good absorption of ammonium, although appreciably less than that obtained in laboratory tests. The obtained material has been spread into an agricultural field, where an increase of the yield has been obtained notwithstanding a significant reduction of the chemical fertilization.

Is it possible to cultivate corn in a sustainable way using a quarry waste

In this preliminary work we investigated the possibility to improve corn cultivation efficiency and sustainability through the use of a quarry waste material rich in zeolite minerals as soil conditioner. Corn grown under traditional fertilization was compared to corn grown on zeolitite amended soil, under fertilization reductions. Corn plants grown on zeolitite treatments showed higher chlorophyll content, a more balanced nitrogen use efficiency and a higher yield compared to control.

Relationship between particle density and soil bulk chemical composition

PurposeAn analytical database containing XRF chemical analyses and real density measurements of unconsolidated sediments of the Padania Plain (Northern Italy) has been used to understand the relationship that exists between the soil particle density (ρs) and their bulk chemical composition.Materials and methodsUsing a linear regression, we built an equation able to link the particle density with the soil elemental composition.Results and discussionPositive correlations were found between ρs and SiO2, MgO, CaO and Na2O and negative correlations with K2O, TiO2, Al2O3, Fe2O3 and LOI, reflecting the presence in the soils of quartz and feldspars/mineral clays respectively.ConclusionsOur equation is very useful because it helps to know the density properties of a soil when it is not possible to measure ρs with a pycnometer. On the other hand, by knowing the ρs, it is possible to have a quite precise knowledge about the chemistry of the studied soils.

The use of particle density in sedimentary provenance studies: the superficial sediment of Po Plain (Italy) case study

In recent years, several approaches for the identification of the provenance of the sediments have been developed. In particular, geochemical, petrographic and mineralogical analyses were applied to the sediments of the Po Plain in order to discriminate the alluvial sediments of the Po River from those coming from Apennine rivers. In this work, we propose an innovative technique based on the measurement of density for the study of the Po Plain alluvial sediments. This study is based on the determination of major and trace elements, particle density and mineralogical composition of 53 superficial sediments. All the data were processed using multivariate statistics. The comparison between density, geochemistry, and granulometry of the Po River and Reno River (the most important Apennine river) samples shows how the densities strictly depend on the chemical-mineralogical composition and grain size of the sediments and, consequently, on the type of hydrographic basin of their respective river. On this basis it can be discriminated the provenance of two different types of alluvial sediments with sufficient precision, determining the density of the unconsolidated alluvial material.

Leaching behaviour of a sandy soil amended with natural and NH4+ and K+ saturated clinoptilolite and chabazite

ABSTRACT Using saturated or enriched zeolites as slow release fertilizers (SRFs) is considered as an environmental-friendly strategy to enhance use of macronutrients in sandy soils. In this paper, two natural zeolites, clinoptilolite (CLI) and chabazite (CHA) were used as mineral precursors to prepare NH4+/K+ saturated clinoptilolite (NH4+/K+-CLI) and chabazite (NH4+/K+-CHA) as zeolitic nutrient sources (ZNSs). Comparison between the nutrient retention capabilities of these ZNSs was one of the main objectives of this study. The NH4+/K+-CLI and NH4+/K+-CHA were prepared by soaking the zeolites in NH4Cl and KCl solutions, respectively. Leaching tests were performed on a sandy soil amended with chemical fertilizers (CFs), NH4+/K+-CLI and NH4+/K+-CHA to evaluate the leaching properties of them. The results indicated that approximately 84% and 88% of the NH4+ and K+ of soils fertilized with CFs were lost during the experiment, respectively. While, the NH4+ and K+ losses from soils amended with NH4+/K+-CLI and NH4+/K+-CHA were 29%, 23%, and 14%, 24%, respectively. Despite of drastic changes in leaching behavior of CFs, nutrient losses from ZNSs were more uniform during the experiments. No significant difference was found between the two studied zeolites on reduction of K+ loss. However, CHA was more effective in preventing NH4+ loss during leaching.

Particle density distribution in a fluvial floodplain

The mechanisms that determine the formation of a floodplain are very well known. At the same time, there is an established correspondence between the sedimentary deposits and density of the particles, whose distribution in the plain is until now poorly constrained. In this work we therefore highlight the spatial distribution of the particle density of soils from the Padania Po Plain in relation to the depositional sub-environment where they have been sampled.

Mitigation of sodium risk in a sandy agricultural soil by the use of natural zeolites

Na+ contamination of irrigation waters represents a global environmental issue for soil structure and plant production. Notwithstanding several techniques for the reduction of Na+ have been proposed in recent years, they generally exhibit disadvantages, including low recyclability and relatively high operational/maintenance costs. In this paper, we propose a natural and eco-friendly solution for the reduction of Na+ risk in coastal agricultural sandy soil (SS), vulnerable to salinity stress. A series of column leaching experiments have been conducted to assess the influence of Italian zeolite-rich tuff (natural zeolites, NZ) addition to soil (NZSS) on Na+ removal, SAR, and CROSS index, under three different salinity scenario. Result showed that the Na+ removal efficiency varied between 46.4 and 54.3% in soil amended with NZ, and analogously SAR index was significantly reduced from 7 to up 13 points. SAR and CROSS indexes resulted better correlated in SS rather than NZSS due to the influence of K+ released by NZ. In conclusion, soil amendment with NZ represents a natural and eco-friendly solution for increasing sandy soil resilience to Na+ risk.