In 2017, a geochemical survey was carried out across the Commune of Santiago, a local administrative unit located at the center of the namesake capital city of Chile, and the concentration of a number of major and trace elements (53 in total) was determined on 121 topsoil samples. Multifractal IDW (MIDW) interpolation method was applied to raw data to generate geochemical baseline maps of 15 potential toxic elements (PTEs); the concentration–area (C-A) plot was applied to MIDW grids to highlight the fractal distribution of geochemical data. Data of PTEs were elaborated to statistically determine local geochemical baselines and to assess the spatial variation of the degree of soil contamination by means of a new method taking into account both the severity of contamination and its complexity. Afterwards, to discriminate the sources of PTEs in soils, a robust Principal Component Analysis (PCA) was applied to data expressed in isometric log-ratio (ilr) coordinates. Based on PCA results, a Sequential Binary Partition (SBP) was also defined and balances were determined to generate contrasts among those elements considered as proxies of specific contamination sources (Urban traffic, productive settlements, etc.). A risk assessment was finally completed to potentially relate contamination sources to their potential effect on public health in the long term. A probabilistic approach, based on Monte Carlo method, was deemed more appropriate to include uncertainty due to spatial variation of geochemical data across the study area. Results showed how the integrated use of multivariate statistics and compositional data analysis gave the authors the chance to both discriminate between main contamination processes characterizing the soil of Santiago and to observe the existence of secondary phenomena that are normally difficult to constrain. Furthermore, it was demonstrated how a probabilistic approach in risk assessment could offer a more reliable view of the complexity of the process considering uncertainty as an integral part of the results.

<p>Organochlorine pesticides (OCPs) are a group of synthetic molecules, consisting of organic structures containing at least one aromatic ring and one covalently bound chlorine atom, widely used for decades in agriculture (as insecticides and fungicides) and, subordinately, in the medical field.</p><p>The study area, corresponding to the Acerra-Marigliano conurbation, is located in the middle sector of the Campania Plain, a wide coastal belt roughly extending from the Garigliano River plain, in the northwest of the Campania region, to the Sarno River basin, southward of the volcanic complex of Mt. Somma-Vesuvius. Most of the study area is occupied by agricultural activities (crops, orchards and vineyard) and, subordinately, by industrial settlements and urbanized areas. A total of 33 surficial composite soil samples were collected across the study area, with an average density of 1 sample per 4 sqkm, to be analyzed for their OCPs content.</p><p>Compared to other synthetic organic pesticides, OCPs show greater environmental persistence and are generally characterized by a marked tendency towards bioaccumulation and biomagnification along trophic chains due to their lipophilic character. The covalent bond between carbon and chlorine in OCP molecules is very stable and resistant to microbial degradation, but some organisms and plants, together with some physical factors (including pH, solar radiation and humidity), can encourage their metabolic degradation.</p><p>The best-known OCP is certainly the dichloro-diphenyl-trichloroethane (DDT), which is one the OCPs defined as Persistent Organic Pollutants by the Stockholm Convention (2001), synthesized since 1873 and used as an insecticide and pesticide since the 1940s. DDT has been, and still is, used to combat malaria in some sensitive areas, such as Africa, India and South America, but its use has been banned in Italy since 1978. DDT can undergo degradation processes, including volatilization or photolysis, whose products are dichloro-diphenyl-dichloroethane and dichloro-diphenyl-dichloroethylene (DDD and DDE, respectively), two compounds with similar properties and, above all, highly persistent. The USEPA (2015) has classified DDT and its metabolites as probably carcinogenic substances for humans, also responsible for damage to the liver, reproductive system and nervous system.</p><p>This study aimed at investigating the local distribution, possible sources and contamination levels of DDT isomers and metabolites in the soils of the study area. In particular, we considered six compounds: p,p′-DDT; o,p′-DDT; p,p′-DDD; o,p′-DDD; p,p′-DDE and o,p′-DDE. Concentration of ΣDDTs (i.e. the sum of the six compounds) ranges from a minimum of 4.13 ng/g to a maximum of 734.75 ng/g.</p><p>The Italian decree 46/2019 establishes a guideline value for DDE, DDD and DDT concentrations in agricultural soils of 10 ng/g. This value is largely exceeded in the whole study area as regards p,p′-DDT and p,p′-DDE, for which the average concentration resulted equal to 70.37 ng/g and 75.94 ng/g, respectively.</p><p>O,p′-DDD and o,p′-DDE show very low concentrations throughout the study area with average concentrations of 1.44 ng/g and 0.75 ng/g, respectively; o,p′-DDT (mean = 5.67 ng/g) and p,p′-DDD (mean = 6.24 ng/g) overcome the guideline mostly in soils collected in the surrounding areas of the towns of Acerra, Brusciano and Marigliano.</p>

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<p>Natural radioactivity depends on primordial radionuclides which decay across a chain of transformations to achieve a stable nuclear state. Transformations involve the emission of particles and photons whose energy can be harmful to organisms even at low-dose. K-40, Th-232 and U-238 are responsible for most of the natural emission of gamma rays from the earth’s crust and volcanic rocks are, in general, the most emissive materials.</p><p>Volcanic rocks and related volcano-sedimentary lithified deposits have been quarried for construction purposes and for road paving, since the Greek times, in the area where the city Naples is located, halfway between the volcanic districts of Phlegrean Field and Mt. Somma-Vesuvius, respectively. For centuries, lithified pyroclastic products, such as grey or yellow tuffs, have been used mainly for buildings and vertical structures; lava blocks from Phlegrean Fields and, since 18<sup>th</sup> century, from Vesuvian effusive materials have been historically used to pave the roads of the old town.</p><p>However, in the last few decades, <span>deteriorated </span><span>historical paving materials of some roads serving areas undergoing renovation have been partially replaced by volcanic materials of Etnean origin (proceeding from Sicily, indeed) or covered/replaced by non-geologic materials (NGMs) (e.g., asphalt).</span></p><p>Considering that 120,000 people live in the old town (over an area of 4 sqkm) being potentially exposed to low-dose ionizing gamma radiations, a survey to estimate the contribution of geological materials to the ambient dose equivalent rate (ADER) was completed. A radiological risk assessment was also completed.</p><p>Specifically, 2548 measurements of ADER (µSv/h) were made in the open air at 0.2 (ADER0.2) and at 1 m (ADER1) above the ground, respectively, using a handheld gamma-ray spectrometer. Besides, a total of 13 samples of paving materials were collected and analyzed by means of a high purity germanium detector at the Center for Ecological-Noosphere in Armenia.</p><p>Results revealed a significant activity of all materials, except for NGMs. ADER1 and ADER0.2 values ​​showed a strong dependence on the distance from the ground in the streets paved with geologic materials, while the distance from the ground resulted to be not relevant for ADER in areas paved by NGMs .</p><p>Based on the ADER1 data, a Monte Carlo simulation was conducted to calculate the outdoor excess lifetime cancer risk (ELCRout) for the population of the study area and for each district belonging to the old town.</p><p>In one of the districts showing the highest average ELCRout, 51 additional ADER1 measurements were also conducted inside private dwellings to assess the indoor ELCR (ELCRin). Finally, the total excess lifetime cancer risk (ELCRtot) was estimated by summing values of ELCRout to ELCRin.</p><p>The average ELCRout obtained for the entire study area (1.33E-03) and for individual districts (from 5.20E-04 to 1.44E-03) exceeds the world average reference value (2.9E-04).</p><p>ELCRin (4.35E-03) and ELCRtot (5.79E-03) are also higher than the average reference values proposed in the literature.</p><p>This study revealed that low-dose gamma radiations, emitted by paving or building materials of volcanic origin can pose a radiological risk to human health.</p>