Special Issue on Advances in Environmental Applied Physics

This Special Issue, “Advances in Environmental Applied Physics”, is dedicated to collecting original papers from eminent researchers in the field of environmental pollutants, which constitute a health risk to the population, increasing the likelihood of incurring cancer. It is noteworthy that, among the various analytical techniques for the assessment of physical and chemical pollutants in the environment, alpha as well as gamma spectrometry are employed to obtain the specific activity of alpha and gamma radionuclides, respectively; ICP-MS can be used to investigate metal concentrations; liquid scintillation counting (LSC) is employed to quantify the activity concentration of tritium, radon, and gross alpha as well as beta; total alpha/beta counting, with the thick-source method, can be used for gross alpha- and beta-specific activity evaluation; and emanometry, in a H₂O setup configuration, can be employed to estimate the gas radon activity concentration.

Furthermore, the main topic of the article titled “Evaluation of Radioactivity and Heavy Metals Content in a Basalt Aggregate for Concrete from Sicily, Southern Italy: A Case Study” is an investigation on the natural and anthropic radioactivity of as well as heavy metals content in a basalt aggregate for concrete from Sicily, Southern Italy, performed as a case study. In particular, the evaluation of the specific activity of radium-226, thorium-232, potassium-40, and caesium-137 radionuclides was performed by using high-purity germanium (HPGe) γ-ray spectrometry, together with the estimation of several indices developed to evaluate the radiological risk for the population related to radiation exposure, i.e., the alpha index (I_α), the radium equivalent activity (Ra_eq), the absorbed γ-dose rate (D), and the annual effective dose equivalent outdoors (AEDE_out) as well as indoors (AEDE_in). Moreover, measurements of the average heavy metals (arsenic, cadmium, copper, mercury, nickel, lead, antimony, thallium, and zinc) concentrations in the analyzed sample were performed by using inductively coupled plasma mass spectrometry (ICP-MS). Furthermore, with the aim to investigate any possible chemical pollution, the enrichment factor (EF), the geo-accumulation index (Igeo), the contamination factor (CF), and the pollution load index (PLI) were assessed. Finally, the identification of the source of the aforementioned radioisotopes of natural origin was carried out by X-ray diffraction (XRD), thus identifying the major mineralogical phases present in the investigated basalt aggregate for concrete [1,2,3].

The article titled “Verification of Estimated Cosmic Neutron Intensities Using a Portable Neutron Monitoring System in Antarctica” has the following featured application: a portable neutron-monitoring system that can be effectively applied to the verification of models used for estimating cosmic radiation intensities over a wide range of altitudes in a harsh environment, such as in Antarctica. Moreover, many ongoing studies for predicting the production rates of cosmogenic nuclides, forecasting changes in atmospheric compositions and climate, assessing the cosmic radiation exposure of aircraft crew and the effects on precise electronic devices, use numerical models that estimate cosmic radiation intensities in the atmosphere. Periodic verifications of these models are desirable to be performed for assuring the reliability of the study outcomes. Here, authors investigated an application of a portable neutron-monitoring system composed of an extended energy range neutron monitor and a small data logger for the monitoring of cosmic neutron intensities in a polar region. As a result of measurements in the East Antarctica region covering a wide range of altitudes (from 30 m to 3762 m), as well as comparisons with the model calculations performed with an analytical model based on comprehensive Monte Carlo simulations (PARMA), it was demonstrated that the portable neutron-monitoring system could be effectively applied to the periodic verification of cosmic neutron intensities that would improve the reliability of related studies [4,5].

In the research paper titled “Multivariate Statistical Analyses and Potentially Toxic Elements Pollution Assessment of Pyroclastic Products from Mt. Etna, Sicily, Southern Italy”, potentially toxic element contamination, which represents a universal problem of major concern, due to several adverse health effects on human beings when permissible concentration levels are overcome, was investigated. In this sense, the assessment of potentially risky elements’ contents in different environmental matrices plays a key role in the safeguarding of the quality of the environment, and thus of strictly correlated public health. In this article, measurements of the average potentially toxic element concentrations in pyroclastic products from Mt. Etna, Eastern Sicily, and Southern Italy were performed together with a comparison with the allowable levels set by Italian legislation, with the aim of evaluating the level of toxicity imposed on the ecosystem. For this purpose, inductively coupled plasma mass spectrometry (ICP-MS) measurements were performed to investigate any possible chemical pollution by potentially risky elements, via the application of different indices such as the enrichment factor (EF), the geo-accumulation index (I_geo), the contamination factor (CF), and the pollution load index (PLI). Finally, a multivariate statistical analysis was performed by processing potentially toxic element contents and pollution indices. It is worth noting that the approach used could be applied, in principle, to the evaluation of chemical risk due to the presence of potentially toxic elements in a large variety of samples of particular environmental interest, and can constitute a guideline for investigations focused on the monitoring of environmental quality [6,7,8].

In the article “Estimation of Cosmic-Ray-Induced Atmospheric Ionization and Radiation at Commercial Aviation Flight Altitudes”, the main source of the ionization of the Earth’s atmosphere, i.e., the cosmic radiation that depends on solar activity as well as geomagnetic activity, was investigated. Galactic cosmic rays constitute a permanent radiation background and contribute significantly to the radiation exposure inside the atmosphere. In this work, the cosmic-ray-induced ionization of the Earth’s atmosphere, due to both solar and galactic cosmic radiation during the recent solar cycles, 23 (1996–2008) and 24 (2008–2019), was studied globally. Estimations of the ionization were based on the CRAC:CRII model produced by the University of Oulu. The use of this model allowed for extensive calculations from the Earth’s surface (atmospheric depth of 1033 g/cm²) to the upper limit of the atmosphere (atmospheric depth of 0 g/cm²). Monte Carlo simulations were performed for the estimation quantities of radiobiological interest with the validated software DYASTIMA/DYASTIMA-R. This study was focused on specific altitudes of interest, such as the common flight levels used in commercial aviation [9,10].

The main topic of the article titled “Natural and Anthropogenic Radioactivity Content and Radiation Hazard Assessment of Baby Food Consumption in Italy” is the natural (⁴⁰K) and anthropogenic (¹³⁷Cs) radioactivity concentration in four different typologies of early childhood (up to two years old) foods, i.e., homogenized fruit, homogenized meat, childhood biscuits, and baby pasta, produced in Italy and sold in Italian large retailers, investigated via high-purity germanium (HPGe) gamma spectrometry. The present study was carried out with the aim of (i) evaluating the background levels of the investigated radionuclides in the analyzed early childhood foods, (ii) identifying whether the twenty analyzed samples were appropriate for infant consumption, and (iii) contributing to the construction of a database on the radioactivity of early childhood foods sold in Italy [11,12].

The paper “A New Methodological Approach for the Assessment of the ²³⁸U Content in Drinking Water” deals with the radiological quality of drinking water, directly associated with the health of the population. Indeed, it is well known that the presence of radionuclides in drinking water constitutes a health risk for humans because the consumption of such water increases the likelihood of incurring cancer. For this reason, all of the studies aimed at developing new methodologies for the qualitative and quantitative analysis of the radioisotopic composition of drinking water are absolutely desired by the international scientific community, as well as by the institutes that deal with the protection of public health. In this paper, a new methodological approach was developed for the evaluation of ²³⁸U content in drinking water. A sample from Paola, Calabria region, Southern Italy, was taken as a case study. The assessment was performed by using high-purity germanium (HPGe) gamma ray spectrometry, with the aim of quantifying the specific activity of the ^234mPa radioisotope after a preconcentration procedure, and thus to assess the activity concentration of ²³⁸U, in a hypothesis of the secular radioactive equilibrium between it and its daughter. The obtained results were validated via a comparison with the ²³⁸U (µg/L) concentration as measured through inductively coupled plasma mass spectrometry (ICP-MS) [13,14].

In the paper “Monte Carlo Simulation-Based Calculations of Complex DNA Damage for Incidents of Environmental Ionizing Radiation Exposure”, the authors present a useful Monte Carlo (MC)-based methodology that can be utilized to calculate the absorbed dose and the initial levels of complex DNA damage (such as double-strand breaks—DSBs) in cases of an environmental ionizing radiation (IR) exposure incident (REI), i.e., a nuclear accident. The objective was to assess the doses and complex DNA damage by isolating only one component of the total radiation released in the environment after an REI that will affect the health of an exposed individual; more specifically, the radiation emitted by radionuclide ¹³⁷Cs in the ground (under an individual’s feet). The authors used a merging of the Monte Carlo N-particle transport (MCNP) code with the Monte Carlo damage simulation (MCDS) code. The DNA lesions were estimated through simulations for different surface activities of a ¹³⁷Cs ground-based γ radiation source. The energy spectrum of the emitted secondary electrons and the absorbed dose in typical mammalian cells were calculated via the use of the MCNP code, and these data are then used as an input in the MCDS code for the estimation of critical DNA damage levels and types. As a realistic application, the calculated dose was also used to assess the excess lifetime cancer risk (ELCR) for eight hypothetical individuals, living in different zones around the Chernobyl Nuclear Power Plant, exposed to different time periods on the days of the accident in 1986. The authors concluded that any exposition of an individual in the near zone of Chernobyl increases the risk of cancer at a moderate to high grade, also connected with the induction of complex DNA damage via radiation. Generally, this methodology has been proven to be useful for assessing γ-ray-induced complex DNA damage levels of the exposed population in the case of an REI, and for better understanding the long-term health effects of the exposure of the population to IR [15,16].

The article titled “Natural Radioactivity and Radon Exhalation from Building Materials in Underground Parking Lots” is focused on the change in natural ionizing radiation and the radon exhalation rates from typical building materials in underground parking lots. The activity concentration of natural radionuclides ²³²Th, ²²⁶Ra, and ⁴⁰K in six important types of construction materials, which are mostly used in Lithuania, were analyzed via the use of high-resolution gamma spectroscopy. The highest values were found in concrete and ferroconcrete samples, and a strong positive correlation (0.88) was observed between radium activity concentration and radon concentration. The activity indices (I_α and I_γ) and radium equivalent activity (Ra_eq), evaluating the suitability of materials for such constructions from the view of radiation safety, were determined. The average values of the calculated absorbed dose rate in samples ranged from 18.24 nGy h⁻¹ in the sand to 87.26 nGy h⁻¹ in ferroconcrete. The calculated annual effective dose was below the limit of 1.0 mSv y⁻¹. The values of the external and internal hazard indices (H_ex and H_in) were all below unity, and the values of I_γ and I_α were below the recommended levels of 0.5 and 1. A dosimetric analysis of underground parking lots was carried out. It was determined that the external equivalent dose rate caused by ²²²Rn progeny radiation in the underground car parking lots varied from 17 to 30% of the total equivalent dose rate [17,18].

The main topic of the paper “Evaluation of the Radiological and Chemical Risk for Public Health from Flour Sample Investigation” is an investigation on flour, in terms of physical and chemical pollutants as well as mineral content; these are of great interest, in view of flour’s high consumption for nutritional purposes. In this study, eleven types of flour (five samples for each one), from large retailers and employed by people for different food cooking purposes, were investigated through high-purity germanium (HPGe) gamma spectrometry in order to estimate natural (⁴⁰K)- and anthropogenic (¹³⁷Cs)-radioisotope-specific activity and, thus, to assess radiological risk due to flour ingestion. Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma emission spectroscopy (ICP-OES) were also employed to evaluate any possible heavy metal contamination and the mineral composition, as well as to perform a multivariate statistical analysis to deduce the flour authenticity. The evaluation of dose levels due to flour ingestion was performed for the age category higher than 17 years, taking into account the average yearly consumption in Italy and assuming this need to be satisfied from a single type of flour as a precaution. All of the obtained results are under the allowable level set by Italian legislation (1 mSv y⁻¹), thus excluding the risk of ionizing radiation effects on humans. As far as heavy metal contamination is concerned, Cd and Pb concentrations were seen to be lower than the threshold values, thus excluding their presence as pollutants. Finally, the multivariate statistical analysis allowed the unambiguous correlation of flour samples with their botanical origins, according to their elemental concentrations [19,20,21].

Finally, the research paper “Assessment of Natural Radioactivity and Radiological Risks in River Sediments from Calabria (Southern Italy)” was developed to carry out a comprehensive radiological assessment of natural radioactivity for river sediment samples from Calabria, Southern Italy, and to define a baseline background for the area on a radiation map. In the studied area, elevated levels of natural radionuclides were expected due to the outcropping acidic intrusive and metamorphic rocks from which the radioactive elements derive. To identify and quantify the natural radioisotopes, ninety river sediment samples from nine selected coastal sampling points (ten samples for each point) were collected as representative of the Ionian and the Tyrrhenian coastline of Calabria. The samples were analyzed via the use of a gamma ray spectrometer equipped with a high-purity germanium (HPGe) detector. The values of mean activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K measured for the studied samples are (21.3 ± 6.3) Bq kg⁻¹, (30.3 ± 4.5) Bq kg⁻¹, and (849 ± 79) Bq kg⁻¹, respectively. The calculated radiological hazard indices showed average values of 63 nGy h⁻¹ (absorbed dose rate), 0.078 mSv y⁻¹ (effective dose outdoors), 0.111 mSv y⁻¹ (effective dose indoors), 63 Bq kg⁻¹ (radium equivalent), 0.35 (Hex), 0.41 (Hin), 0.50 (activity concentration index), and 458 µSv y⁻¹ (annual gonadal equivalent dose, AGED). In order to delineate the spatial distribution of natural radionuclides on the radiological map and to identify the areas with low, medium, and high radioactivity values, Surfer 10 software was employed. Finally, a multivariate statistical analysis was performed to deduce the interdependency and any existing relationships between the radiological indices and the concentrations of the radionuclides. The results of this study, also compared with values of other locations of the Italian Peninsula characterized by similar local geological conditions, can be used as a baseline for future investigations of the radioactivity backgrounds of investigated areas [22,23,24].