Geogenic versus anthropogenic behaviour and geochemical footprint of Al, Na, K and P in the Campania region (Southern Italy) soils through compositional data analysis and enrichment factor

Geochemical studies that focus on environmental applications tend to approach the chemical elements as individual entities and may therefore offer only partial and sometimes biased interpretations of their distributions and behaviour. A potential alternative approach is to consider a compositional data analysis, where every element is part of a whole. In this study, an integrated methodology, which included compositional data analysis, multifractal data transformations and interpolation, as well as enrichment factor analysis, was applied to a geochemical dataset for the Campania region, in the south of Italy, focusing in particular on the behaviour, footprints and sources of a smaller pool of elements: Al, Na, K and P. The initial dataset included 3669 topsoil samples, collected at an average sampling density of 1 site per 2.3 km2, and analyzed (after an aqua regia extraction) by a combination of ICP-AES and ICP-MS for 53 elements. Frequency based methods (Clr biplot, Enrichment Factor computation) and frequency spatial-method (fractal and multifractal plots) allowed identifying the relationships between the elements and their possible source patterns in Campania soils in relation to a natural occurring concentrations in geogenic material (rocks, soils and sediments) or human input. Results showed how the interpretation of concentration and behaviour of Al, Na, K and P was enhanced thanks to the application of data log-ratio transformation in univariate and multivariate analysis compared to the use of raw or log-normal data. Multivariate analyses with compositional biplot allowed the identification of four element associations and their potential association with the underling geology and/or human activities. When focusing on the smaller pool of elements (Al, P, K and Na), these relationships with the unique geology of the region, were largely confirmed by multifractal interpolated maps. However, when the local background was used for the calculation of the enrichment factor, the resulting interpolated maps allowed to identify smaller areas where the greater concentrations of P could not be possibly associated to a mineralisation (e.g., ultrapotassic rocks) but were more likely to be associated to anthropogenic input such as agriculture activities with potentially extensive use of phosphate fertilizers. The integrated approach of this study allowed a more robust qualitative and quantitative evaluation of elemental concentration, providing in particular new and vital information on the distribution and patterns of P in soils of the Campania region, but also a viable, more robust, methodological approach to regional environmental geochemistry studies

Source patterns and contamination level of polycyclic aromatic hydrocarbons (PAHs) in urban and rural areas of Southern Italian soils

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants (POPs). They have been identified as a type of carcinogenic substance and are relatively widespread in environment media such as air, water and soils, constituting a significant hazard for human health. In many parts of the world, PAHs are still found in high concentrations despite improved legislation and monitoring, and it is therefore vital defining their profiles, and assessing their potential sources. This study focused on a large region of the South of Italy, where concentration levels, profiles, possible sources and toxicity equivalent quantity (TEQ) level of sixteen PAHs were investigated. The survey included soils from five large regions of the south of Italy: 80 soil samples (0–20 cm top layer) from urban and rural locations were collected and analysed by Gas chromatography-mass spectrometry (GC-MS). Total PAHs and individual molecular compounds from the US Environmental Protection Agency (EPA) priority pollutants list were identified and measured. Results showed that 16PAHs varied significantly in urban and rural areas, and different regions presented discordant characteristics. Urban areas presented concentrations ranging from 7.62 to 755 ng/g (mean = 84.85 ng/g), whilst rural areas presented ranges from 1.87 to 11, 353 ng/g (mean = 333 ng/g). Large urban areas, such as Rome, Naples and Palermo, exhibited high PAHs total concentration, but high values were also found in rural areas of Campania region. Different PAHs molecular ratios were used as diagnostic fingerprinting for source identification: L WMPAHs/HWMPAHs, Fluo/(Fluo +Pyr), BaA/(BaA +Chr), Ant/(Ant +Phe), and IcdP/(IcdP +BghiP). These ratios indicated that PAHs sources in the study area were mainly of pyrogenic origin, i.e. mostly related to biomass combustion and vehicular emission. On the other hand, values in Sicilian soils seemed to indicate a petrogenic origin, possibly linked to emissions from crude oil combustion and refineries present in the region. Finally, results allowed to calculate the Toxicity equivalent Quantity (TEQ BAP) levels for the various locations sampled, highlighting that the highest values were found in the Campania region, with 661 ng g-1 and 54.20 ng g-1, in rural and urban areas, respectively. These findings, which could be linked to the presence of a large solid waste incinerator plant, but also to well-documented illegal waste disposal and burning, suggest that exposure to PAH may be posing an increased risk to human health in some of the studied areas

Status, sources and contamination levels of organochlorine pesticide residues in urban and agricultural areas: a preliminary review in central–southern Italian soils

Organochlorine pesticides (OCPs) are synthetic chemicals commonly used in agricultural activities to kill pests and are persistent organic pollutants (POPs). They can be detected in different environmental media, but soil is considered an important reservoir due to its retention capacity. Many different types of OCPs exist, which can have different origins and pathways in the environment. It is therefore important to study their distribution and behaviour in the environment, starting to build a picture of the potential human health risk in different contexts. This study aimed at investigating the regional distribution, possible sources and contamination levels of 24 OCP compounds in urban and rural soils from central and southern Italy. One hundred and forty-eight topsoil samples (0–20 cm top layer) from 78 urban and 70 rural areas in 11 administrative regions were collected and analysed by gas chromatography–electron capture detector (GC–ECD). Total OCP residues in soils ranged from nd (no detected) to 1043 ng/g with a mean of 29.91 ng/g and from nd to 1914 ng/g with a mean of 60.16 ng/g in urban and rural area, respectively. Endosulfan was the prevailing OCP in urban areas, followed by DDTs, Drins, Methoxychlor, HCHs, Chlordane-related compounds and HCB. In rural areas, the order of concentrations was Drins > DDTs > Methoxychlor > Endosulfans > HCHs > Chlordanes > HCB. Diagnostic ratios and robust multivariate analyses revealed that DDT in soils could be related to historical application, whilst (illegal) use of technical DDT or dicofol may still occur in some urban areas. HCH residues could be related to both historical use and recent application, whilst there was evidence that modest (yet significant) application of commercial technical HCH may still be happening in urban areas. Drins and Chlordane compounds appeared to be mostly related to historical application, whilst Endosulfan presented a complex mix of results, indicating mainly historical origin in rural areas as well as potential recent applications on urban areas. Contamination levels were quantified by Soil Quality Index (SoQI), identifying high levels in rural areas of Campania and Apulia, possibly due to the intensive nature of some agricultural practices in those regions (e.g., vineyards and olive plantations). The results from this study (which is in progress in the remaining regions of Italy) will provide an invaluable baseline for OCP distribution in Italy and a powerful argument for follow-up studies in contaminated areas. It is also hoped that similar studies will eventually constitute enough evidence to push towards an institutional response for more adequate regulation as well as a full ratification of the Stockholm Convention

Coupling compositional data analysis (CoDA) with hierarchical cluster analysis (HCA) for preliminary understanding of the dynamics of a complex water distribution system: The Naples (South Italy) case study

Providing safe tap water has been a global concern. Water scarcity, the ever-increasing water demand, temporal variation of water consumption, aging urban water infrastructure and anthropogenic pressure on the water resources are the greatest challenges in effective water supply. In the present article, the waters exploited to be introduced in a water distribution system (i.e. input water) and tap waters are collected for determination of metal(loid)s, ions and physicochemical parameters. Seasonal variation is observed in the chemistry of the input waters. Further, the annual total dissolved solids (TDS) of the tap waters range from 200 to 1000 mg l-1 which stresses the importance of interconnections between urban water reservoirs for mixing different water types and adjusting water quality. It is complicated in populated cities like Naples with an old water distribution network, which also challenges setting up hydraulic and water quality models. The preliminary data visualization indicates the different chemical characteristics of some samples that are supposed to receive water from the same source. This might explain the difficulties in understanding the network layout in Naples. Thus, the compositional nature of chemical data was considered in hierarchical cluster analysis (HCA) to seasonally study water transfer between urban water reservoirs and define the source of tap water in each city area. The proposed method can preliminarily divide the pipe network into unique clusters and provide an overview of the relationships between different components when representative models cannot be set up due to limited information about network characteristics. Hence, advanced water distribution simulation and management is encouraged. This journal i

Atlante geochimico–ambientale dei suoli della Campania

L’Atlante illustra i risultati ottenuti dalle indagini sui suoli superficiali della Campania. Su un’area di 13.595 Km2 sono stati raccolti 3.535 campioni di suolo e analizzati con una metodologia che combina l’ICP–MS (Spettrometria di massa al plasma accoppiato induttivamente) e l’ICP–ES (Spettrometria a emissione al plasma accoppiato induttivamente). Per ogni elemento chimico sono riportate le proprietà, le applicazioni, gli effetti sulla salute, nonché la distribuzione geochimica in Campania. Le carte geochimico–ambientali che compongono il volume rappresentano una “fotografia” risalente al momento del campionamento e potranno essere utilizzate in futuro come riferimento per la valutazione dell’impatto ambientale delle attività antropiche presenti sul territorio. Sono anche uno strumento di notevole valenza ambientale, soprattutto per quanto concerne la valutazione dei tenori di fondo (background) dei vari elementi chimici esaminati

A New Approach for Aquifer Vulnerability Assessment: the Case Study of Campania Plain

We are going to propose a new method for aquifer vulnerability assessment, named Susceptibility Index-Contamination Degree (SICODE). Starting from the assumption that soil chemistry impacts on infiltration water quality, geochemical tool such as the soil contamination degree index (CD) was combined with hydrogeological parameters in order to enhance previous well-known index (DRASTIC, Susceptibility Index). The study has been carried out at the Campania Plain (CP) aquifer, which mostly supplies the drinking water distribution system of Napoli (Southern Italy). The survey area extends from Mt. Vesuvius to the metropolitan area of Napoli and it can be considered an interesting field laboratory in order to test hydro-geochemical methods and models since both diffuse anthropogenic pollution and natural contamination sources (e.g. interaction processes between groundwater and rock) coexist. Three models have been compared. Our results have showed that DRASTIC is not the best model to be applied to urbanized environments since it does not account for the anthropogenic influence. Susceptibility Index (SI), which incorporates land use parameter, has showed a more detailed map of vulnerability degree and it better answers the local variability of human pressure. However, the proposed SICODE method completely meets the geochemical fingerprint of soil. Sensitivity analysis has revealed a high variability of the parameters due to the local heterogeneity of the analyzed system conditions. A comparison between the groundwater nitrates distribution and the predicted vulnerability has showed that. SICODE gave more accurate predictions than the other ones. This study has provided the evidence that combining hydrogeological and geochemical tools may enhance aquifer vulnerability assessment

Uranium, thorium and potassium insights on Campania region (Italy) soils: Sources patterns based on compositional data analysis and fractal model

Uranium, thorium and potassium are distinguished in different compartments of the environmental media according to the inputs, the fate and the distribution patterns that occur in the ecosystems. Thus, an understanding of the sources patterns and behaviours of these elements in soils, their rock-soil relationships and potential toxicity or deficiency problems associated with them is nowadays a relevant concern for environmental protection and human health. A robust compositional computation analysis coupled with frequency spatial-method (Fractal model) is applied on 3 selected elements (U, Th and K), based on a large dataset of 7134 topsoil samples over the whole Campania region, and investigated elements concentrations were analysed (after aqua regia extraction) by inductively coupled plasma mass spectrometry (ICP-MS). In this survey, U concentrations ranged from 0.05 to 43.2 mg kg−1 with a mean value of 3.35 mg kg−1, Th concentrations ranged from 0.3 to 64.30 mg kg−1 with a mean values of 11.95 mg kg−1 and K concentrations ranged from 0.03 to 5.97% with a mean value of 0.68%. The mean values for U and Th are slightly above the mean crustal abundances, while K is slightly below them. Fractal mapping of Centred-log transformed (clr) data of investigated elements show that the U, Th and K geochemical anomalies can be ascribed to geology-related volcanic sources. Indeed, the highest values in soils were assessed in the surveyed alkaline magmatic areas in the central-western part of the region characterized by volcanic rocks, whereas lowest values are found in areas characterized by silico-clastic and carbonate deposits, occurring mostly in the southern and eastern part of the region. Evidence from this study showed that compositional data transformations such as clr transformation could help to avoid artefacts, prior to statistical computations