Dario Di Giuseppe

Heavy metals in soils and sedimentary deposits of the Padanian Plain (Ferrara, Northern Italy): characterisation and biomonitoring

PurposeThis contribution investigates agricultural soils and sedimentary deposits in the province of Ferrara (Padanian alluvial plain, Northern Italy) in order to: examine their genesis; to define the geochemical background of the area; and to evaluate the existence of anthropogenic contamination. Moreover, environmental risk related to the presence of potentially toxic heavy metals that can be transferred into agricultural products (and consequently bio-accumulated in the food chain) was also assessed.Materials and methodsThe analyses (reported in an extensive supplementary dataset) include XRD, XRF and ICP-MS assessment of bulk sediments, tests of metal extraction with aqua regia, as well as analyses of local agricultural products, i.e. biomonitoring which is important in the evaluation of element mobility.Results and discussionBased on the results, GIS-based geochemical maps were produced and local background levels were defined. This approach demonstrated that high concentrations of Cr and Ni is a natural (geogenic) feature of the local alluvial terrains, which in turn is related to the origin and provenance of the sediments, as confirmed by the lack of top enrichment in all of the investigated sites. Tests of metal extraction and analyses of agricultural products provide guidelines for agricultural activities, suggesting that extensive use of sewage sludge, industrial slurry and manure (that are often rich in metals) should be minimised.ConclusionsThe dataset reported in this paper shows that the agricultural terrains of the studied alluvial plain are not characterised by anthropogenic heavy metal pollution. In spite of the elevated natural background of Cr and Ni, most of the local agricultural products do not show significant evidence of bio-magnification. Exceptions are represented by forage grass (alfalfa) and corn (maize) that tend to uptake As and Ni, respectively. This demonstrates that in agricultural areas, a geochemical risk assessment must include both soil and plant investigations.

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.

Geochemical characterization and biomonitoring of reclaimed soils in the Po River Delta (Northern Italy): implications for the agricultural activities.

This geochemical study is focused on the easternmost part of the Po River alluvial plain in Northern Italy, which is interested by widespread agricultural activities, investigating a reclaimed sector of the Province of Ferrara, known as “Valle del Mezzano” (Mezzano Low Land, hereafter reported as MLL) characterized by peat-rich soils. The chemical–mineralogical characterization of these reclaimed soils is important to compare the local geochemical backgrounds with those recorded in other sectors of the River Po plain and to monitor if the observed concentration exceeds critical thresholds. The reported analyses include (a) measurement of the soil salinity, (b) nutrient evaluation, (c) major and trace element concentrations carried out on bulk soils, (d) tests of metal extraction with both aqua regia and EDTA to highlight the distinct elemental mobility and (e) phyto-toxicological measurement of heavy metal concentrations in plants (Lactuca sativa acephala) grown on the studied soils. The results indicate (1) high soil salinity, often with drastic increase of sodium and chloride along the soil profiles, (2) high nitrogen content (in part related to anthropogenic activities) on superficial horizons and nitrate decrease along the soil profiles and (3) comparative enrichments in heavy metals with respect to other soils of the province, which indicate that peat deposits are effective in trapping metals from anthropogenic sources. This, in turn, implies potential geochemical risks for the agricultural activities. In this regard, specific concerns are related to the high nickel and arsenic content of MLL soils due to the mobility of these elements and their attitude to be taken up by plants.

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.

Soil–water interactions in soils of the Padanian Plain (Ferrara, Northern Italy): insights on heavy-metal mobility and phytoavailability

The soils of the Po River plain, developed on the alluvial sediments, are often characterized by high concentration of heavy metals, in particular chromium and nickel. These geochemical anomalies are “geogenic”, i.e. related to the specific nature of the “mother rocks” outcropping in the basin that typically include mafic and ultramafic lithologies. The elevated heavy metal backgrounds of soils potentially represent an effective geochemical risk considering the toxicity of these elements. In order to delineate soil quality thresholds and to provide guidelines for human activities (e.g. agriculture) the current legislation takes into consideration the “pseudototal” metal content obtained with aqua regia extraction tests. However, only a fraction of this chemical budget is available for plant and human uptake. Soil leaching tests with deionized water plausibly provide a better analogue to simulate the natural soil-water interactions, in order to predict the behavior of metals in the environment. In particular, in this paper we investigate with water leaching tests soils sampled in the surrounding of Ferrara (eastern part of the Po plain) that were previously characterized by bulk XRF analyses and aqua regia extractions. The approach gives insights on the element-specific transport parameters, giving clues for a) the possible contamination of the natural water and b) the soil-to-plant uptake processes and phytoavailability. Results, expressed as solid-water partition coefficients, highlight that nickel is significantly more mobile and bioaccessible than chromium and should be monitored in the local agricultural products to avoid its possible transfer and bioaccumulation in the food chain.

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.