title: Airborne asbestos fibres monitoring in tunnel excavation.
abstract: Tunnelling across ophiolitic formation with Naturally Occurring Asbestos (NOA) can release fibres into the environment, exposing workers, and the population, if fibres spread outside the tunnel, leading to increased risk of developing asbestos-related disease. Therefore, a careful plan of environmental monitoring is carried out during Terzo Valico tunnel excavation. In the present study, data of 1571 samples of airborne dust, collected between 2014 and 2016 inside the tunnels, and analyzed by SEM-EDS for quantification of workers exposure, are discussed. In particular, the engineering and monitoring management of 100 m tunnelling excavation across a serpentinite lens (Cravasco adit), intercalated within calcschists, is reported. At this chrysotile occurrence, 84% of 128 analyzed samples (from the zone closer to the front rock) were above 2 ff/l. However, thanks to safety measures implemented and tunnel compartmentation in zones, the asbestos fibre concentration did not exceed the Italian standard of occupational exposure (100 ff/l) and 100% of samples collected in the outdoor square were below 1 ff/l. During excavation under normal working conditions, asbestos concentrations were below 2 ff/l in 97.4% of the 668 analyzed samples. Our results showed that air monitoring can objectively confirm the presence of asbestos minerals at a rock front in relative short time and provide information about the nature of the lithology at the front. The present dataset, the engineering measures described and the operative conclusions are liable to support the improvement of legislation on workers exposure to asbestos referred to the tunnelling sector, lacking at present.
authors.affiliation: Department of Earth, Environment and Life Sciences, Corso Europa 26, I-16132 Genova, Italy. Electronic address: gaggero@dipteris.unige.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Gaggero
authors.affiliation: Department of Earth, Environment and Life Sciences, Corso Europa 26, I-16132 Genova, Italy. Electronic address: elisa.sanguineti@unige.it.
authors.forename: Elisa
authors.initials: E
authors.lastname: Sanguineti
authors.affiliation: Department of Earth, Environment and Life Sciences, Corso Europa 26, I-16132 Genova, Italy. Electronic address: adrian.yus.gonzalez@edu.unige.it.
authors.forename: Adrián
authors.initials: A
authors.lastname: Yus González
authors.affiliation: Department of Earth, Environment and Life Sciences, Corso Europa 26, I-16132 Genova, Italy. Electronic address: gaiamaria.militello@edu.unige.it.
authors.forename: Gaia Maria
authors.initials: GM
authors.lastname: Militello
authors.affiliation: COCIV, Via Renata Bianchi 40, I-16152 Genova, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Scuderi
authors.affiliation: COCIV, Via Renata Bianchi 40, I-16152 Genova, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Parisi
mesh_terms: D001194:Asbestos; D004391:Dust; D004784:Environmental Monitoring; D006801:Humans; D007558:Italy; D016273:Occupational Exposure
chemical_list: D004391:Dust; D001194:Asbestos
keywords: Airborne asbestos monitoring; Dust characterization; Naturally occurring asbestos (NOA); Occupational health; SEM-EDS; Tunnelling