Domenico Cicchella

Multifractal IDW interpolation and fractal filtering method in environmental studies: an application on regional stream sediments of (Italy), Campania region

In recent years environmental geochemical mapping has assumed an increasing relevance and separation of background values to evaluate pollution is, probably, even more critical than the separation between background and anomalies in mineral prospecting studies. The recognition of background values assumes particular relevance as a function of national environmental legislation, which fixes intervention limits for some elements, such as the harmful ones (e.g. As, Cd, Hg, Pb). In this paper a recently developed multifractal IDW interpolation method and a fractal filtering technique are applied to separate natural background and anthropogenic values for the compilation of environmental geochemical mapping from stream sediment samples of Campania region (Italy), where no mineralization occurs. To discuss the application of these recently developed techniques the elements Pb and U were selected because they show two completely different situations, the high Pb values being mostly of anthropogenic origin and high U values being mostly of geogenic origin. The new fractal filtering method works well in both extreme situations.

Background and baseline concentration values of elements harmful to human health in the volcanic soils of the metropolitan and provincial areas of Napoli (Italy)

In this paper, we discuss baseline geochemical maps of elements harmful to human health compiled using concentration data of 982 volcanic soil samples from the metropolitan and provincial areas of Napoli (1171 km2). Each sample was digested in aqua regia and analysed by ICP-MS and ICP-ES. For the compilation of baseline geochemical maps, we apply a recently developed multifractal IDW interpolation method and spectral analysis (S-A) using a new geochemistry-dedicated GIS (GeoDAS). The geochemical baseline in an area of heavy anthropogenic impact, such as the Neapolitan territory, includes the geogenic natural content (background) and the anthropogenic contribution in the soils. The definition and distinction of background (geogenic) values, as opposed to baseline values, are very important in environmental studies because legislation typically fixes the intervention limits for both organic and inorganic substances in soils as a function of local background values. Maps obtained by the S-A method show high baseline values for some metallic elements (Pb, Zn, Sb, Hg, Cd, Cr, Cu) which denote a clear anthropogenic contribution, due to the long period of constant human activities in the study area. These maps also show a high geogenic contribution most probably derived from hydrothermal fluids because the study area is located between two active volcanic fields (Mt. Somma–Vesuvius and Campi Flegrei), where geothermal fluids have been used for spas since Roman times. The maps obtained using the S-A method, implemented in GeoDAS, reflect both the geogenic and anthropogenic contribution, so they must be considered as baseline maps. In order to obtain background values, to be used as reference values for the environmental Italian Law 471/1999, we have applied the concentration–area fractal method (C-A) to classify the pixel values of baseline maps. R-mode factor analysis helped in interpreting data controlled by anthropogenic sources as opposed to those controlled by geogenic sources.

Heavy metal pollution and Pb isotopes in urban soils of Napoli, Italy

Lead isotope analysis is an increasingly widespread tool in the study of environmental pollution as Pb isotope compositions do not change during industrial and environmental processes, and always reflect their source origin. In this study we present the results of R-mode factor analysis for associations between chemical elements in Neapolitan soils, combined with the distribution of Pb concentrations and Pb isotope compositions in order to differentiate natural from anthropogenic metal sources. Results show Neapolitan urban soils to be significantly enriched in Pb, Hg, Zn, Sb, and to a lesser extent in Cu, Cd, Cr and Ni. Lead isotope measurements form a trend suggesting mixing between two end-member compositions, one of clear natural origin (geogenic) and another related to human activities (anthropogenic). Lead isotope investigations demonstrate that road traffic is one of the main sources of metal pollution.

Palladium and platinum concentration in soils from the Napoli metropolitan area, Italy: possible effects of catalytic exhausts

Soils from the Napoli metropolitan area (Italy) were evaluated for Pt and Pd concentrations. One hundred and ninety-five (195) samples were collected from residual soils and non-residual soils from flower-beds in a 120 km(2) area on a 0.5 km grid in the downtown-urbanized area and on 1 km grid in suburban zones. The soils <100 mesh size fraction (150 microm) was analyzed for Pt, Pd and 37 other elements by ICP-ES and ICP-MS after aqua regia digestion. Pt and Pd contents range between <2 and 52 microg/kg and between <10 and 110 microg/kg, respectively. A large number of samples from the metropolitan area were characterized by anomalous values for Pt (>6 microg/kg) and Pd (>17 microg/kg). Non-residual soils from flower-beds are located mainly in the urbanized downtown areas subject to heavy traffic and have higher Pt and Pd contents than residual soils from suburban areas. Geochemical maps show a strong correlation between roads with major traffic flow and high Pt and Pd concentrations. In addition, data from most of the downtown flower-beds fall within the three-way catalytic converters (TWC) field identified by [Ely JC, et al. Environ Sci Technol; 35:3816-3822]. This suggests that emissions of abraded fragments from vehicle exhausts may be the source of the high values and geographic distributions of Pd and especially Pt in urban soils of Napoli. Catalytic converters (Pt/Pd/Rh) have been mandatory for gasoline-powered vehicles in Europe since 1993. Italy permitted the use of non-catalytic motor until January, 2002. This is responsible for the high values for both Pt and Pd in the non-residual soils of the urban areas of Napoli.

Urban geochemical mapping in the Campania region (Italy)

This work reviews the results of research conducted in the last five years on urban soils of the Campania region, southern Italy. Approximately 2000 topsoil samples were collected and analysed for 40 elements, among which are included the potentially harmful elements (PHE). The two most relevant objectives achieved were the determination of background levels for each element, using concentration–area (C–A) and separation–anomaly (S-A) algorithms, and the production of an extensive cartography, published in a series of geochemical atlases. The latter show that high PHE concentrations, exceeding many times the local natural backgrounds (especially Pb, Hg, Sb, Zn), are found in the most densely populated areas, often affected by heavy vehicular traffic and industrial activities. Many soil samples exceed the limits set for PHE by the Italian Ministry of the Environment in law DM 471/99 for residential land use. The geochemical maps can prove to be very useful both for scientists and professionals working towards the restoration of contaminated areas, as well as serving to refine the Italian environmental legislation to be more effective in local situations.

Interpolation methods for geochemical maps : a comparative study using arsenic data from European stream waters

A geochemical map of As in water from the FOREGS Geochemical Atlas of Europe, performed using the Alkemia interpolation method based on moving weighted median (MWM), and a comparable map prepared by kriging are compared with an As map prepared with a new multifractal inverse distance weighted (MIDW) interpolation method using GeoDas™ software. The colour scale classification of the MIDW interpolated map of As is based on the concentration–area (C-A) fractal method which allows images to be subdivided into components representing specific features on the ground related, for example, to geology. Conventional techniques, such as MWM and kriging, are shown to smooth out the local variability of the geochemical data. The problem is most serious in maps prepared by kriging which erroneously show large areas of Europe to have high levels of As in water. On the other hand, MIDW creates a geochemical map in which information about the local data structure is retained. This is essential in distinguishing anomalies from background values. The information provided by background and anomaly maps, using the MIDW and fractal filtering methods, are shown to give more reliable upper limits of background values.

Assessment of the topsoil heavy metals pollution in the Sarno River basin, south Italy

Abstract The Sarno River basin area is one of the most polluted in Europe and it is due to the waste products of the tomato industry, the leather tanneries and the pharmaceutical industry. This area also has been densely populated and urbanized since the Middle Bronze Age, as testified by the presence of numerous archeological sites, including the ancient Pompeii town, and environmental degradation that characterizes the area is absolutely unacceptable. This paper represents a detailed study to assess the potentially harmful element content of topsoils. In total, 283 soil samples were collected and analyzed, after an aqua regia extraction, by a combination of inductively coupled plasma atomic emission and inductively coupled plasma mass spectrometry for 53 elements. Univariate and multivariate analyses were carried out to show the single-element geochemical distribution and the distribution of factor scores of the elemental associations resulting from R-mode factor analysis. Maps showing elements and the association factor score distributions have been obtained using GeoDAS and ArcGIS software. The assessment of the soil contamination was also carried out using the contamination factor and degree of contamination. The results obtained indicate that soil pollution has different anthropogenic sources. Specifically, Cr pollution derives from tanneries discharging wastewaters in the main water bodies of the basin while Cu contamination seems to depend on widespread agricultural practices. Tin, Pb, Hg, Zn, Cd, Sb anomalies are found mainly in urban and industrial areas, sometimes close to roads with high traffic levels while there is a substantial coincidence with background values for other elements (Co, Ni, Se, Tl and V).

Environmental geochemical maps of Italy from the FOREGS database

The Geochemical Atlas of Italy addresses the need for geochemical mapping of the country, based on FOREGS procedures. Data from samples of Italian topsoil, subsoil, stream water, stream sediment and floodplain sediment have been extracted from the FOREGS database and supplemented with data from eight new sample sites. In total 360 geochemical maps have been produced and spatial correlations have been found between the underlying geology and element abundances in the sampled media. The aim of the Geochemical Atlas of Italy is to document background/baseline chemical element variation at the national scale. It is found to be a suitable tool to support government decision-makers to assess trigger and action limits at the local scale, when considered in the light of the complex spatial variability of Italian geology. Maps presented here demonstrate that low density geochemical mapping is a viable tool to obtain an impression of natural element variation at the country scale and to identify areas where more detailed sampling is advisable.

Assessment of lead pollution in topsoils of a southern Italy area: Analysis of urban and peri-urban environment.

Exposure to lead (Pb) may affect adversely human health. Mapping soil Pb contents is essential to obtain a quantitative estimate of potential risk of Pb contamination. The main aim of this paper was to determine the soil Pb concentrations in the urban and peri-urban area of Cosenza-Rende to map their spatial distribution and assess the probability that soil Pb concentration exceeds a critical threshold that might cause concern for human health. Samples were collected at 149 locations from residual and non-residual topsoil in gardens, parks, flower-beds, and agricultural fields. Fine earth fraction of soil samples was analyzed by X-ray Fluorescence spectrometry. Stochastic images generated by the sequential Gaussian simulation were jointly combined to calculate the probability of exceeding the critical threshold that could be used to delineate the potentially risky areas. Results showed areas in which Pb concentration values were higher to the Italian regulatory values. These polluted areas were quite large and likely, they could create a significant health risk for human beings and vegetation in the near future. The results demonstrated that the proposed approach can be used to study soil contamination to produce geochemical maps, and identify hot-spot areas for soil Pb concentration.

Platinum group element distribution in the soils from urban areas of the Campania region (Italy)

This paper represents a detailed study to assess the platinum group element (PGE) content of topsoils from urban areas in the Campania region (Italy), following on from previous work. Samples were collected from residual and non-residual soils from flowerbeds in the urban areas of Avellino, Benevento and Caserta (characterized by low population density, LPD), and in Salerno (a city with high population and high automobile traffic densities). The soils (<100-mesh size fraction, i.e. <150 μm) were analysed for Pt, Pd and Rh by fire assay ICP-MS and for 37 other elements by ICP-AES and ICP-MS after a modified aqua regia digestion. In LPD cities, PGE concentrations were close to background values (with the exception of the industrial areas), but Salerno proved to be contaminated by PGEs. Platinum, Pd and Rh concentrations are in the <0.1–278, <0.5–432 and 0.07–47 ppb range, respectively. Moreover, a high correlation among Pt, Pd and Rh (R=0.98), and between PGEs and other typical traffic-emitted metals such as Cr, Cu, Sb and Sn has been detected only in Salerno. Finally, the statistical analysis pointed out a lower background for PGEs in soils formed on sedimentary rocks (in the eastern sector of Caserta, in Benevento and Salerno) compared to those formed on volcanic rocks (Avellino and the western area of Caserta).