Massimo Angelone

Pedogeochemical evolution and trace elements availability to plants in ophiolitic soils

Abstract The results of a study on the distribution of major and trace elements in the bulk soils and in the EDTA-extractable fraction in nine soil profiles and in some related plant species from the Mt. Ferrato area (Florence, Italy) are reported. The topsoils display a moderate enrichment in those elements generally related to the organic matter content (e.g. Cd, Co, Cu, Pb, Zn) although many of the parent material characteristics, especially with regard to the major elements (high Mg content, low Ca/Mg ratios, low K concentrations) are still preserved. The data obtained from the EDTA-extractable element concentrations show a general decreasing trend with depth within the profiles. Aluminium, Cr and Ti are the least EDTA-extractable elements, while Mg presents a high tendency to form organic complexes with EDTA. Heavy metals are generally enriched in the topsoil in relation to the organic matter content, confirming they enter the biogeochemical cycle. No ‘toxic levels’, especially as regards heavy metals, have been found. Data on trace element content in plants are below the concentrations considered excessive or toxic. However, high Mn abundances (420 mg/kg), Cr (5.5 mg/kg) and Ni (> 10 mg/kg) have been sporadically found. Therefore, no evident signs of pollution occur in the area investigated. The well known infertility of the ophiolitic soils could be a consequence of a ‘synergism’ resulting from the combined effects of major and trace elements.

Distribution of rare earth elements in marine sediments from the Strait of Sicily (western Mediterranean Sea): Evidence of phosphogypsum waste contamination

Concentrations of rare earth elements (REE), Y, Th and Sc were recently determined in marine sediments collected using a box corer along two onshore-offshore transects located in the Strait of Sicily (Mediterranean Sea). The REE+Y were enriched in offshore fine-grained sediments where clay minerals are abundant, whereas the REE+Y contents were lower in onshore coarse-grained sediments with high carbonate fractions. Considering this distribution trend, the onshore sediments in front of the southwestern Sicilian coast represent an anomaly with high REE+Y concentrations (mean value 163.4 μg g(-1)) associated to high Th concentrations (mean value 7.9 μg g(-1)). Plot of shale-normalized REE+Y data of these coastal sediments showed Middle REE enrichments relative to Light REE and Heavy REE, manifested by a convexity around Sm-Gd-Eu elements. These anomalies in the fractionation patterns of the coastal sediments were attributed to phosphogypsum-contaminated effluents from an industrial plant, located in the southern Sicilian coast.

Determination of Platinum Group Elements and Evaluation of Their Traffic-Related Distribution in Italian Urban Environments

Abstract The platinum (Pt) distribution in urban matrices, soils and dusts was studied in five cities, from north (Padova), central (Rome and Viterbo), and south (Naples and Palermo) Italy, in order to obtain a large set of data concerning pollution from autocatalysts. Quantitative analyses, made by inductively coupled plasma mass-spectroscopy (ICP-MS), show a beginning of Pt enrichment in urban soils, with concentration ranges of 0.1–5.7 ng/g (Padova), 7–19.4 ng/g (Rome), 4.9–20 ng/g (Viterbo), 4.7–14.3 ng/g (Naples), and 0.2–3.9 ng/g (Palermo). These results can be related to vehicular traffic, because the concentrations decrease with the distance from the roads. The high concentrations found in road and tunnel dusts (up to 1177 ng/g) confirm these samples as the major reserve of the particulate matter that is released with the exhaust fumes (which is responsible for the Pt enrichment). Qualitative analyses by laser-ablation-ICP-MS (LA-ICP-MS) were used, in addition, to determine the real presence of the catalyst particles in the urban dusts. The association of the analytical signals of cerium, platinum, and rhodium was used as a fingerprint to distinguish the catalyst particles from the other components of the urban dusts. The scanning electron microscopy (Energy Dispersive Spectrometer-Scanning Electron Microscope; EDS-SEM) qualitative analysis was also used to characterize the morphology of the autocatalyst and its related elemental distribution.

Potentially Harmful Elements in Urban Soils

Throughout the human history, the anthropic activity inevitably leads to a legacy of increased PHE concentration in the environment. Nowadays the urban environment can be considered the main habitat for humans. Therefore, the acknowledgment and the understanding of the impact of PHEs in urban soils and dusts is imperative in order to develop a plan for the sustainable management of urban areas, which should limit this impact on human and environmental health. A historical background regarding urban soil contamination is presented, along with an overview of the PHEs and PGEs found in urban soils. As humans are daily exposed to PHEs present in air, water and soil, studies are focusing on their long-term effects and on the toxicological impact of PHE (PHEs’) combinations, rather that of single elements. The importance of a comprehensive assessment of PHEs in urban soils and dusts, including their bioavailability, is discussed.

A field screening test for the assessment of concentrations and mobility of potentially toxic elements in soils: a case study on urban soils from Rome and Novi Sad

The increasing demand for environmental pollution control results in the development and use of new procedures for the determination of dangerous chemicals. Simple screening methods, which can be used directly in the field for a preliminary assessment of soil contamination, seem to be extremely advantageous. In our laboratory, we developed and optimized a rapid test for a preliminary evaluation of both the concentration and the mobility of some potentially toxic metals in soils. This screening test consists of a single extraction of the soil sample with a buffer solution, followed by the titration of the extracted solution with dithizone to determine the contents of bi-valent heavy metals (such as Pb, Cu, Zn, and Cd). This screening method was then directly applied in the field during the sampling campaign in the framework of an Italian–Serbian collaborative project, finalized in the study of metal availability in soils. The results obtained in the field with the rapid test were compared with those obtained in the laboratory following the conventional procedure commonly used to evaluate metal bioavailability (diethylenetriaminepentaacetic extraction). Moreover, selected samples were analyzed sequentially in the laboratory using the standardized BCR three-step sequential extraction procedure. The screening test gave results conceptually in good agreement with those obtained via the BCR procedure. These preliminary data show that the proposed screening test is a reliable method for the preliminary rapid evaluation of metal total concentrations and of potential metal mobility in soils, supporting sampling activities directly in the field.