Passive biomonitoring of airborne microplastics using lichens: A comparison between urban, natural and protected environments.

Currently, natural and urban ecosystems are affected by different types of atmospheric deposition, which can compromise the balance of the environment. Plastic pollution represents one of the major threats for biota, including lichens. Epiphytic lichens have value as bioindicators of environmental pollution, climate change, and anthropic impacts. In this study, we aim to investigate the lichen bioaccumulation of airborne microplastics along an anthropogenic pollution gradient. We sampled lichens from the Genera Cladonia and Xanthoria to highlight the effectiveness of lichens as tools for passive biomonitoring of microplastics. We chose three sites, a "natural site" in Altipiani di Arcinazzo, a "protected site" in Castelporziano Presidential estate and an "urban site" in the centre of Rome. Overall, we sampled 90 lichens, observed for external plastic entrapment, melt in oxygen peroxide and analysed for plastic entrapment. To validate the method, we calculated recovery rates of microplastics in lichen. Particularly, 253 MPs particles were detected across the 90 lichen samples: 97 % were fibers, and 3 % were fragments. A gradient in the number of microplastic fibers across the sites emerged, with increasing accumulation of microplastics from the natural site (n = 58) to the urban site (n = 116), with a direct relationship between the length and abundance of airborne microplastic fibers. Moreover, we detected the first evidences of airborne mesoplastics entrapped by lichens. On average, the natural site experienced the shortest fibre length and the centre of Rome the longest. No differences in microplastics accumulation emerged from the two genera. Our results indicated that lichens can effectively be used for passive biomonitoring of microplastic deposition. In this scenario, the role of lichens in entrapping microplastics and protecting pristine areas must be investigated. Furthermore, considering the impact that airborne microplastics can have on human health and the effectiveness of lichens as airborne microplastic bioindicators, their use is encouraged.

Considerations on chemical composition of psammoma bodies: Automated detection strategy by infrared microspectroscopy in ovarian and thyroid cancer tissues.

Ectopic calcifications are observed in many soft tissues and are associated with several diseases, including cancer. The mechanism of their formation and the correlation with disease progression are often unclear. Detailed knowledge of the chemical composition of these inorganic formations can be very helpful in better understanding their relationship with unhealthy tissue. In addition, information on microcalcifications can be very useful for early diagnosis and provide insight into prognosis. In this work the chemical composition of psammoma bodies (PBs) found in tissues of human ovarian serous tumors was examined. The analysis using Micro Fourier Transform Infrared Spectroscopy (micro-FTIR) revealed that these microcalcifications contain amorphous calcium carbonate phosphate. Moreover, some PB grains showed the presence of phospholipids. This interesting result corroborates the proposed formation mechanism reported in many studies according to which ovarian cancer cells switch to a calcifying phenotype by inducing the deposition of calcifications. In addition, other techniques as X-ray Fluorescence Spectroscopy (XRF), Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) and Scanning electron microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDX) were performed on the PBs from ovary tissues to determine the elements present. The PBs found in ovarian serous cancer showed a composition comparable to PBs isolated from papillary thyroid. Based on the chemical similarity of IR spectra, using micro-FTIR spectroscopy combined with multivariate analysis, an automatic recognition method was constructed. With this prediction model it was possible to identify PBs microcalcifications in tissues of both ovarian cancers, regardless of tumor grade, and thyroid cancer with high sensitivity. Such approach could become a valuable tool for routine macrocalcification detection because it eliminates sample staining, and the subjectivity of conventional histopathological analysis.