Fabio Terribile

Characterization of heavy metals in contaminated volcanic soils of the Solofrana river valley (southern Italy)

A number of volcanic agricultural soils from the Solofrana river valley (southwestern Italy), irrigated for a long time with contaminated river water or subjected to overflowing, were collected and examined for fundamental soil parameters and total content and distribution of Fe, Cr, Cu, Mn, Ni, Pb and Zn. Micromorphological properties, the effect of main soil characteristics on the distribution of heavy metals in the various forms, and metal uptake or effects on vegetables were also investigated. Chromium and Cu were the only metal contaminants, occurring in soils in broad ranges of concentrations (Cr 62–335 and Cu 70–565 mg kg 1 ) and in the surface horizons always above the regulatory levels (Cr 150, Cu 120 mg kg 1 ), as established by the Italian Ministry of the Environment for soils of public, private and residential areas. Chromium and Cu, but also Ni, Pb and Zn, were concentrated in silt (20–2 Am) and clay ( 50%). Mn was uniformly distributed among all the extracted fractions. For all metals the soluble and exchangeable forms made a small contribution to the total. Significant amounts of Cr and Cu were recovered in the acid ammonium oxalate extraction, suggesting association of metals with shortrange-order aluminosilicates and organo–mineral complexes. The amounts of metals extracted by oxalate were found to be approximately equal to two thirds of the sequentially removed non-residual amounts. The results of DTPA extraction confirmed the low bioavailability of heavy metals in soil. The metal concentration in dwarf beans and lettuces growing on one contaminated soil did not exceed the maximum concentration recommended by the European Union. However, the enzyme activities in the bean roots indicated the induction of anti-oxidative defense mechanisms due to metallic stress. Optical microscopy (OM) showed occurrence of clay and silt coatings along elongated pores in the surface and subsurface soil horizons, suggesting a risk of metal-rich sediment transfer along the soil pore network during water movement. D 2003 Elsevier Science B.V. All rights reserved.

Soil hydraulic behaviour of a selected benchmark soil involved in the landslide of Sarno 1998

Abstract A multidisciplinary approach was adopted in this paper in order to study the very complex and unpredictable phenomenon of rainfall-triggered landslides. Physical and chemical measurements were made on a selected benchmark soil involved in the landslide of Sarno (Southern Italy) in May 1998. Water behaviour inside the soil, covering a typical slope of the area, was simulated using a two-dimensional simulation model. Sensitivity analyses of the model showed that a few uncertainties regarding input data (climatic and physical) can be accepted without substantially changing output data, namely soil water storage values. The effects of the interruption of the pedological continuity of the slope were simulated in terms of total weight encumbering the bottom of the soil stratification just behind a section of discontinuity. There resulted an increase of more than 30% in soil water storage with respect to the same section of the undisturbed slope. It causes an overloading which produces the same values of soil tangential pressure as those of peak strength measured by direct shear tests. Notwithstanding the simplifications introduced to carry out this study, the proposed approach demonstrates the possibility of quantifying the consequences of some human or natural changes regarding soil-covered slopes and hence the potential of improving landslide risk assessment.

Mineralogy, micromorphology and chemical analysis of andosols on the Island of São Miguel (Azores)

Abstract A study concerning soil genesis was conducted on surface and buried volcanic soils of Sao Miguel island (Azores). Of eight soil profiles, three were selected for detailed study of pedogenesis. A series of techniques which include chemical, micromorphological, XRD and DXRD analysis, micropicking on impregnated soil blocks, TEM-EDS and IR spectroscopy analyses were used. The soils showed an incipient to moderate degree of weathering, as typically occurs in many young volcanic districts. Four different stages of soil development were clearly identified. The first stage of soil development was characterised by dominance of primary minerals and some allophane and ferrihydrite formation, with an Feo/Fed ratio of about 0.86 (LOM soil). The second stage of soil development was indicated by halloysite and ferrihydrite formation in the lower horizons along with an Feo/Fed ratio of about 0.62 (SAN surface soil). The third stage of soil development was characterized by halloysite and ferrihydrite formation in the lower horizon but also by clay illuviation and stronger pumice weathering, and an Feo/Fed ratio of about 0.51 (SAN buried soil). The fourth stage of soil development concerned the LIX soils (buried soils older than 5000 years BP) which had a much higher content in hydrated halloysite and considerable amounts of goethite and hematite. These soils exhibit the most expressed weathering features and an Feo/Fed ratio of about 0.25. The presence of young surface soils and well-developed buried soils can be explained by (i) the longer pedogenesis of buried soils or, possibly, by (ii) the presence of a climate more seasonal than that of the present day.

MIXED-LAYER KAOLINITE-SMECTITE MINERALS IN A RED-BLACK SOIL SEQUENCE FROM BASALT IN SARDINIA (ITALY)

Clay minerals from soils of a red-black soil complex developed from basaltic parent material in Sardinia are formed along a short toposequence (200 m). At the foot of the sequence, a clay-rich, black Vertisol forms, whereas at the summit, the soil is a dark reddish-brown Inceptisol. X-ray diffraction, infrared spectroscopy (FTIR), cation exchange capacity (CEC) and permanent and variable charges analyses were used, and the data show that clay minerals varied according to soil horizon and topographic position of the soil. Clay minerals in the Inceptisol are dominated by kaolinite and mixed-layer kaolinitesmectite (K-S, K:S >0.5), whereas the Vertisol contains smectites and K-S with K:S proportions <0.5. In the Vertisol, the proportion of kaolinitic layers in the K-S increases from the C horizon (K:S ∼0.35–0.40) to the Ap horizon (K:S ∼0.40–0.45). This soil clay-mineral distribution, in relation to topography, is similar to that reported for other (kaolinitic) red-black (smectitic) soil associations in subtropical and tropical areas. The sequence forms by downward drainage on summits and slopes, and buildup of ions in ‘lows’ produces smectites. Fourier transform infrared spectra indicate that two types of smectite are formed in the C horizon of the Vertisol; one is more ferric (Fe-beidellite, nontronite), the other more aluminous. Mineralogical evolution in the soil profile (from C to Ap horizon) shows a decreasing proportion of ferric smectite layers (compared to the more aluminous smectite layers). This would indicate that ferric smectite layers are preferentially transformed (or dissolved) to give kaolinite layers, with Fe precipitating as oxides and/or oxy-hydroxides or retained partly in kaolinite layers. Because the surface properties of clay minerals are related to mineralogy, the CEC (33–41 cmol kg−1) in the brown Inceptisol is ∼50% pH-dependent charge while in the Vertisol up to ∼75% of the CEC (48–61 cmol kg−1) comes from accessible permanent charges.

Late Quaternary climatic changes in Northern Cilento (Southern Italy): an integrated geomorphological and paleopedological study

Abstract This paper reports a contribution to the knowledge of the local morphodynamic and pedogenetic response to Late Quaternary climatic changes in Northern Cilento (Southern Italy). Three representative geomorphological units and associated paleosols have been characterised in detail by field work, chemical and mineralogical analyses, and micromorphological observations of thin sections. The data confirm an intense degree of weathering and a complex history of soil formation, often representing different environments in contrast with the present pedoclimatic regime. Two of the three profiles reveal a polygenetic character, recording typical interglacial conditions characterised by high temperatures and humidity with important soil development, followed by the occurrence of periglacial conditions possibly occurring during cold glacial stages (namely the Last Glacial) at mid-latitude coastal regions of Southern Italy. The third paleosol appears essentially monogenetic and developed under interglacial-like conditions.

Micromorphological evidence of paleoenvironmental changes in Northern Cilento (South Italy) during the Late Quaternary

Abstract Three representative soil profiles developed during the Late Quaternary in Northern Cilento (South Italy) were studied by optical microscopy and SEM-EDS observation of thin sections to examine soil features as evidence for past climatic fluctuations. Two of the profiles are polygenetic and the third monogenetic. All these have a clear interglacial imprint, whereas the polygenetic profiles also contain other features, which can be related to periglacial conditions during the stadial glacial periods although in midlatitude coastal areas. All the paleosols show a strong marine influence during development, which probably resulted from windblown processes or submergence during past interglacial phases.

Characteristics and genesis of volcanic soils from South Central Italy: Mt. Gauro (Phlegraean Fields, Campania) and Vico lake (Latium)

South Central Italy (Latium and Campania regions) is an interesting geo-graphic area to study soil development in volcanic materials because of: (a) the presence of volcanoes active during late Pleistocene and Holocene; (b) the occurrence of several pyroclastic deposits of known ages, and c) the Mediterranean climate (mesic and ustic/xeric pedoclimate). This district, often called “Campano-Laziale”, is geographically divided into the Roman and Campanian petrographic provinces (Figure 1), and is characterized by extensive volcanic deposits with a wide variety in composition of lava and volcanic tephra ranging from alkali-trachytic to latitic (Scandone et al. 1991, Di Vito et al. 1999, De Vivo et al. 2001). Many of the volcanoes in Central Italy are stratovolcanoes formed by alkali-potassic magmatic lava, characteristic of the Campano-Roman petrographic Province. The activity dates back 1300 ka (Sollevanti 1983, Bidini et al. 1984, Barbieri et al. 1988). Two areas have been investigated: an old volcano, the Vico Caldera in the Latium district and a young volcano in the Phlegraean Fields, Cam-pania. Eruptions have been characterized by a variety of explosive event sequences and magnitudes in the past 1500–2000 ka. The Vico volcano consists of lavas of various composition, including leucitites, leucite–tephrites or leucite–phonolites in the first cycle and trachy-andesitic or latitic products in the second cycle (Lulli and Bidini 1978, Lulli et al. 1988, Scandone et al. 1991). The actual body of the Vico volcano is a lake of 7–8 km in diameter that occupies an area of 150 km

A Combined Approach of Sensor Data Fusion and Multivariate Geostatistics for Delineation of Homogeneous Zones in an Agricultural Field

To assess spatial variability at the very fine scale required by Precision Agriculture, different proximal and remote sensors have been used. They provide large amounts and different types of data which need to be combined. An integrated approach, using multivariate geostatistical data-fusion techniques and multi-source geophysical sensor data to determine simple summary scale-dependent indices, is described here. These indices can be used to delineate management zones to be submitted to differential management. Such a data fusion approach with geophysical sensors was applied in a soil of an agronomic field cropped with tomato. The synthetic regionalized factors determined, contributed to split the 3D edaphic environment into two main horizontal structures with different hydraulic properties and to disclose two main horizons in the 0–1.0-m depth with a discontinuity probably occurring between 0.40 m and 0.70 m. Comparing this partition with the soil properties measured with a shallow sampling, it was possible to verify the coherence in the topsoil between the dielectric properties and other properties more directly related to agronomic management. These results confirm the advantages of using proximal sensing as a preliminary step in the application of site-specific management. Combining disparate spatial data (data fusion) is not at all a naive problem and novel and powerful methods need to be developed.

Spatial analysis of clay content in soils using neurocomputing and pedological support: a case study of Valle Telesina (South Italy)

The spatial analysis of soil properties by means of quantitative methods is useful to make predictions at sampled and unsampled locations. Two most important characteristics are tackled, namely the option of using complex and nonlinear models in contrast with (also very simple) linear approaches, and the opportunity to build spatial inference tools using horizons as basic soil components. The objective is to perform the spatial analysis of clay content for validation purposes in order to understand whether nonlinear methods can manage soil horizons, and to quantitatively measure how much they outperform simpler methods. This is addressed in a case study in which relatively few records are available to calibrate (train) such complex models. We built three models which are based on artificial neural networks, namely single artificial neural networks, median neural networks and bootstrap aggregating neural networks with genetic algorithms and principal component regression (BAGAP). We perform a validation procedure at three different levels of soil horizon aggregations (i.e. topsoil, profile and horizon pedological supports). The results show that neurocomputing performs best at any level of pedological support even when we use an ensemble of neural nets (i.e. BAGAP), which is very data intensive. BAGAP has the lowest RMSE at any level of pedological support with