Asbestos detection in construction and demolition waste by different classification methods applied to short-wave infrared hyperspectral images

In this study, different multivariate classification methods were applied to hyperspectral images acquired, in the short-wave infrared range (SWIR: 1000-2500 nm), to define and evaluate quality control actions applied to construction and demolition waste (C&DW) flow streams, with particular reference to the detection of hazardous material as asbestos. Three asbestos fibers classes (i.e., amosite, chrysotile and crocidolite) inside asbestos-containing materials (ACM) were investigated. Samples were divided into two groups: calibration and validation datasets. The acquired hyperspectral images were first explored by Principal Component Analysis (PCA). The following multivariate classification methods were selected in order to verify and compare their efficiency and robustness: Hierarchical Partial Least Squares-Discriminant Analysis (Hi-PLSDA), Principal Component Analysis k-Nearest Neighbors (PCA-kNN) and Error Correcting Output Coding with Support Vector Machines (ECOC-SVM). The classification results obtained for the three models were evaluated by prediction maps and the values of performance parameters (Sensitivity and Specificity). Micro-X-ray fluorescence (micro-XRF) maps confirmed the correctness of classification results. The results demonstrate how SWIR-HSI technology, coupled with multivariate analysis modelling, is a promising approach to develop both "off-line" and "online" fast, reliable and robust quality control strategies, finalized to perform a quick assessment of ACM presence.

Guidelines for asbestos remediation at Italian superfund sites

Asbestos is now banned in 52 countries. Although Italy banned asbestos in 1992, up until that date it had been one of the main producer nations of asbestos and asbestos-containing materials, and asbestos-related contamination is still widespread in the country. To reduce asbestos-related health effects, Italy has adopted many laws and regulations regarding exposure thresholds and remediation tools. Even so, there are legislative gaps that are making it difficult to manage related risks especially in the operative phase. The lack of standard procedures at a national level regarding emergency shutdown and remediation as well as reference thresholds for specific risk situations creates difficulties and different actions when dealing with the cleanup of Italian asbestos superfund sites. The authors propose operative guidelines for asbestos remediation at Italian superfund sites. INAIL, the reference national organization for asbestos-related matters, acting as an advisor to a number of state, regional, and local authorities, examined the main asbestos-related risk situations in Italy and proposed the most appropriate actions to take. The detailed analysis of many actual cases of risk, in part through inspections and the management of cleanup actions at asbestos Italian superfund sites, resulted in proposals to modify existing procedures and thresholds, which were subsequently discussed with all national, regional, and local scientific bodies. After more than two years of work and discussion at a national level, INAIL-DIPIA-Asbestos Group drafted new Guidelines for Asbestos Remediation at Italian Superfund sites, and officially submitted them to the Environment Ministry. The Ministry then adopted the document in regard to all asbestos Italian superfunds. This recently released document is also a useful reference for contaminated sites at a regional and local level. The operative Guidelines for Asbestos Remediation at Italian Superfund sites may also be of use at an international level for countries that have already banned asbestos and are engaged in remediation activity and for countries that have not yet banned asbestos but wish to adopt risk prevention measures.