The proposal aims at improving the knowledge about the association between health and environmental effects of particulate matter (PM) and of its chemical composition and sources. The scientific approach is based on the interdisciplinarity of the research group and will focus on the integration of different observation systems and monitoring methods.
PM samples originated from different sources will be collected and analysed by consolidated and innovative analytical methods, thereby reaching a very detailed knowledge of their organic and inorganic chemical composition. Plant and animal model organisms will be exposed in vivo under controlled conditions to the same dusts. Oxidative stress and other biological responses will be then evaluated and correlated to dusts chemical composition: the acquisition of molecular, cellular and metabolic data will provide information on both single cell and whole-animal responses, while the combination of ecophysiological and metagenomic approach (applied to community structure of the phyllosphere microbiome), will be used to define the plants response.
The same integrated approach will be applied to monitor the Terni (central Italy) basin, which is characterized by the presence of several anthropic PM sources and by a severe stagnation of the air masses. The spatial distribution of PM and of its chemical components, obtained by using innovative low-flow, self-powered samplers, will be compared with the results achieved by plants and humans on-site bio-monitoring, in order to verify the findings obtained by the exposure under controlled conditions and to propose an integrated method transferable to other monitoring campaigns.
The proposed research presents several characteristics of originality, innovation and feasibility, which mainly derive from the application to PM of research approaches that had already demonstrated their potential in different applications. However, the choice of the field samples constitutes an innovation itself: the use of dusts from specific sources having a very different chemical composition will facilitate the study of the relationships between chemical composition and biological effects in both animal and plants. The collection of PM2.5 and PM10 field samples will be performed by innovative low-flow, self-powered samplers (Smart Sampler, by FAI Instruments), working at a very low time-resolution (30-40 days). The long sampling duration will improve the representativeness of the collected samples. Most of the sampling sites will be located in Terni, a city of the Central Italy situated in an intra-mountain depression. It is affected by some relevant PM sources (vehicular traffic, domestic heating, a power plant for waste treatment, a steel plant) and suffers from a very low mixing capacity of the lower atmosphere, being thus an ideal area for air pollutant mapping. Samplers will be located in various sites of the studied area in order to obtain the spatial distribution of PM and of its chemical components. Measured concentrations will thus have a common background contribute and will be differentiated only by local and identified sources. Therefore, the differences among biological response in the most impacted areas could be more easily attributed to specific sources and chemical compounds.
A comprehensive knowledge of the chemical composition of samples is of primary importance for a better characterization of sources and for studying their association with the observed biological effects. The project will provide a very detailed chemical analysis of samples, which will include both organic and inorganic compounds. Oxidative potential of dusts will be measured by different methods and correlated to its capability of inducing oxidative stress in living organism, in order to verify the predictive ability of the considered a-cellular tests. The NMR analysis of dusts, which was applied only in very few PM studies, will enable the identification and quantification of the main organic compounds, filling one of the major gap in the chemical knowledge of this complex environmental matrix. NMR technique will also offer the opportunity of exploiting the potential of metabolomics to detect biomarkers of stress and to delineate the modes of action of xenobiotics in living organisms.
The in vivo exposure has been poorly applied to study the biological effects of PM, but it is crucial for understanding the toxicological pathways of PM interaction with living organisms. Deposition of particles on vegetation in urban and industrial areas is still poorly investigated (Fares et al., 2016, Env Poll 218:1278). In particular, there is still a gap of knowledge for what concerns the physiological effects of particles on plant physiology. This project will contribute to define new non-destructive and non-invasive indicators of plant functionality under particle stress, which could be helpful to biomonitor particle pollution in urban and industrial areas. Moreover, the combination of the ecophysiological and metagenomic approaches could define the plants response to different compounds of PM.
In parallel, the effects on animals will be evaluated utilizing the simple model organism C. elegans, which combines the advantages of the in-vivo and in-vitro approaches. The acquisition of molecular, cellular and metabolic data will provide relevant information on single cell and whole-animal responses in terms of oxidative stress and other biological responses. Soluble and insoluble PM fractions will be studied separately allowing us to clarify the role held by the bio-accessibility of chemical compounds.
Furthermore, the human biomonitoring study will provide new evidences about the relationship between PM exposure and oxidative stress, using a total-exposure assessment approach. Besides, the choice of children will allow two main advantages: firstly, children are not exposed to some known oxidizing factors, such as smoking, alcohol, or chemicals used in workplaces; secondly, children are not little adults both in term of exposure and susceptibility to adverse effects and they merit to be evaluated with targeted researches.