National Research Project - GEO06

PRINCIPAL INVESTIGATOR: Giovanni B. ANDREOZZI
TITLE: HYDROX - HYDRous- vs OXo-components in minerals: adding new pieces to the Earth’s H2O cycle puzzle
FUNDING AGENCY: Progetto PRIN 2020, Ministero Università e Ricerca

START DATE: maggio 2022
END DATE: maggio 2025
ABSTRACT:
“The pale blue dot”: these famous words by the astronomer Carl Sagan (1934-1996) briefly summarize the main feature of our planet within the Solar System, i.e., the abundance of surficial H2O. Water is crucial for life as we know it. However, there is a general consensus on accepting that Earth is able to sustain life not only for the occurrence of liquid H2O, but also for the presence of active geodynamic processes, able to maintain stable physical-chemical conditions on the planet surface. In this respect, the occurrence of H2O in the Earth’s interior is crucial as it controls, for instance, melting and viscosity of the convecting mantle, and thus volcanism and plate tectonics. Consequently, both plate tectonics and H2O cycle are the fundamental elements that make planet Earth a life-sustaining planet.
It is well-known that oceans cover more than three-quarter of the Earth surface, but they represent only ca. 0.025% of the planet mass. Accordingly, taking into account the mass of crustal and mantle rocks, even low amounts of hydrated minerals are able to store several oceans of H2O, representing the largest reservoir of this compound. It is thus clear that without an atomistic comprehension of the H2O speciation in minerals it will be impossible to achieve a deep understanding and a correct modelling of a great number of planetary processes. Indeed, in crust and mantle environments, under variable pressure (P), temperature (T), and oxygen fugacity (fO2) conditions, mineral phases usually considered as anhydrous may be carrier of H2O, whereas others usually considered as hydrated can partly lose their H2O or even become anhydrous. Physical constraints and crystal-chemical mechanisms of those reactions are not fully understood yet.
In this framework, the project "HYDRous- vs OXo-components in minerals: adding new pieces to the Earth’s H2O cycle puzzle (HYDROX)" aims at clarifying H2O behaviour in minerals. Our attention will be focused on both Nominally Anhydrous Minerals (NAMs) and Nominally Hydrous Minerals (NHMs). Through an integrated chemical, spectroscopic and structural approach, selected samples of four mineral groups (i.e., silicate garnets, hollandites, amphiboles and tourmalines, two NAMs and two NHMs, respectively) will be experimentally studied with the objective to define their H2O speciation mechanisms, providing also useful data for a deeper understanding of H2O cycle in our planet.

 

PRINCIPAL INVESTIGATOR: Paolo BALLIRANO
TITLE: FIBRES: a multidisciplinary mineralogical, crystal-chemical and biological project to amend the paradigm of toxicity and cancerogenicity of mineral fibres
FUNDING AGENCY: Ministero dell’istruzione, dell’Università e della Ricerca, PRIN Bando 2017

START DATE: novembre 2019
END DATE: marzo 2023
ABSTRACT:
MINERAL FIBRES are ubiquitous on the Earth and compose a significant fraction of the airborne particulate. The vast realm of mineral fibres includes asbestos minerals and fibrous erionite that are classified as carcinogenic substances. Although in the last 30 years mineral fibres have been the subject of intensive toxicological studies, the mechanisms by which they prompt cyto- and geno-toxic damage in vivo are not yet fully understood. Without a clear picture of the role that all the crystal-chemical and physical
parameters play in inducing adverse effects, a general quantitative model explaining the toxicity/carcinogenicity of mineral fibres cannot be drawn. With this uncertainty, global issues of social and economic importance cannot be solved. For example, although the toxicity potential of chrysotile asbestos is still highly debated worldwide, this mineral fibre is still used today in “a safe way” in 72% of the world countries. The lack of a quantitative assessment of the toxicity of these materials has another drawback: mineral fibres of unknown toxicity may occur in the natural environment or being in use, causing exposure to the population. Specifically, the FIBRES project is aimed at highlighting the role in inducing toxicity effects of fibres' parameters that have never been considered or deeply investigated to date:

  1. SURFACE IRON SPECIES
    Iron is considered to play a role in determining the toxicity of mineral fibres because, when present at the surface, it promotes the release of toxic hydroxyl radicals. In FIBRES, the nature of these iron atoms occurring at specific surface sites and the mechanism promoting their activity in the different fibre species will be investigated by crystal-chemical, spectroscopic and microscopic methods, combined with free-cell in vitro tests for the release of hydroxyl radicals, the most reactive and short-lived oxygen species (ROS).
  2. BIODURABILITY
    In FIBRES, the different kinetic behaviour of mineral fibres during the intracellular dissolution will be assessed quantitatively by in vitro acellular tests mimicking the lung’s environment. The kinetics and products of dissolution will be investigated by chemical, crystallographic, spectroscopic and microscopic methods. Moreover, the potential toxic effects of such compounds will be tested by analysing several biomarkers that play a key-role in the pathways related to cellular damage as adaptive response. So, the biological effects of the fibres, classified as non-biodurable (chrysotile), biodurable (amphibole asbestos), and biodurable but with ion exchange (zeolite erionite), will be carried out using both 2D and 3D in vitro physiological relevant biodynamic models of human cells from different target tissues. In 3D in vitro cultures, cells are permitted to grow or interact with their surroundings in all three dimensions similar to how they would in vivo.
  3. THE ‘TROJAN HORSE-TYPE EFFECT'
    Mineral fibres are complex crystal-chemical reservoirs that may release their toxic cargo in the cellular environment during the dissolution process. This mechanism has been observed for nanoparticles for which ion release elicited by the acidic conditions of the lysosomal cellular compartment is responsible for the sequence of events associated with their induced toxicity. Hence, the toxicity potential of mineral fibres must be revised including this effect. To do this, the dissolution and release of toxic metals in simulated lung fluids of natural specimens with different loads will be investigated with chemical and spectroscopic methods. Special attention will be given to the production of ROS and to the cyto- and geno-toxic actions of these fibres.
  4. INTERFERENCE WITH THE CA-MEDIATED INTRACELLULAR CROSS TALK PROMPTING CELL APOPTOSIS
    Apoptosis is a process able to efficiently eliminate damaged cells. Tumour cells have the peculiarity to evade apoptosis and consequently survive and proliferate also in presence of DNA damages, two peculiar hallmarks of cancer. Apoptosis can be activated by several pathways and among them the release of calcium in cytosol plays a crucial role. If the Ca cross talk is deficient, the cycle of apoptotic pathways is interrupted, and malignant cells are let free to grow. Zeolite erionite is a peculiar fibre because it possesses ion exchange capacity. In FIBRES, we will evaluate if ion exchange is active during the phagocytosis process of the erionite fibres causing interference with the Ca cross talk. This mechanism will be also investigated by analysing in vitro the apoptotic program.

 

PRINCIPAL INVESTIGATOR: Alessandro PACELLA
TITLE: Caratterizzazione cristallochimica e studio della reattività di superficie di fibre minerali di interesse ambientale e sanitario ai fini di un'accurata analisi del rischio di contaminazione.
FUNDING AGENCY: INAIL (Istituto Nazionale Assicurazione Infortuni sul lavoro). Bando BRIC INAIL 2019

START DATE: maggio 2020
END DATE: aprile 2022
ABSTRACT: 
It is well know from many decades that exposure to asbestos have been linked to numerous health problems and respiratory diseases such as asbestosis, lung cancers and mesothelioma. The high tensile strength, flexibility, electrical and thermal resistence of asbestos led to its use in several mechanical and commercial applications such as thermal insulation, building materials, fire- and bulletproof materials, texile products, and many more. Therefore, to limit its exposure in working places, specific regulations have been developed. In particular, the current legislation focuses on the processes related to the extraction and processing of asbestos, as well as on the production, use and disposal of asbestos containing materials.
However, asbestos is also widespread in rocks and soils (i.e. Naturally Occuring Asbestos, NOA) and can therefore be released into the environment following weathering processes or human activities. In fact, significant levels of airborne fibers have been observed during excavation activities, such as infrastructure constructions or agricultural activities. In addition, there are hundreds of other fibrous minerals occurring in rocks and soils, such as erionite and fluoro-edenite, showing carcinogenicity like asbestos. However, for many of these fibrous minerals there are no data on their potential toxicity so far.
The presence of NOA can have negative impacts on both small (schools and homes) and large (highways and mines) building projects, especially when not previously detected and the risk management not designed. Notably, a correct risk management can only be achieved if the location and extent of the asbestos bearing outcrops, the amount of fibers potentially released following rocks and soils disturbance and their potential toxicity are well known.
Toxicological studies showed that the interactions between mineral fibers and biological environment are strongly dependent on their morphology, surface chemistry and biopersistence. In particular, both the presence and the coordination state of the iron on the mineral surface are considered by the biomedical community as the key factors of the fibre toxicity. Furthermore, in the last years a lot of work has been dedicated to the development of protocols for a more accurate evaluation of the toxicity of fibrous materials. However, there are still many gaps and uncertainties in the correlations between the physical/crystal-chemical and morphological parameters of the mineral fibers and their surface reactivity and toxicity. The knowledge of these correlations has several implications: 1) it provides a powerful tool to measure the toxicity of both asbestos and “not regulated” mineral fibres; 2) it reveals the parameters of a mineral fibre that are active in stimulating carcinogenicity; 3) it allows to evaluate the hazard due the presence of NOA; 4) it offers a strategy for developing specific cancer therapies.
This goal can only be achieved by adopting an innovative multidisciplinary approach including geology, mineralogy, surface chemistry and biochemistry.

 

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