Asbestiform Antigorite from New Caledonia

Asbestiform antigorite from New Caledonia

Dr. Jasmine Rita Petriglieri

Department of Chemistry, University of Torino

Centro Scansetti «G. Scansetti» Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates Universe of fibres ALL PARTICLES

ELONGATE OTHER Commercial/regulated definition PARTICLES (EMP) NOA are the six minerals that are currently identified as asbestos (were commercially INORGANIC ORGANIC exploited). minerals, mineraloids, and e.g., plant fibres and material made from minerals synthetic fibres

Mineralogical definition

Discriminate fibrous mineral from non- ASBESTIFORM MINERAL FIBRES NON ASBESTIFORM (EMPs from mass fibre, cross fibre and slip fibrous form (e.g., acicular, tabular, INORGANIC FIBRES fibre occurrences ) prismatic, …). Chemical alteration of mineral is considered.

REGULATED OTHER ROCK FORMING ASBESTOS MAN MADE Health-oriented definition MINERALS and erionite, fluoro-edenite, INORGANIC MINERALOIDS Identify any hazardous elongated mineral chrysotile, amosite, winchite, richterite, FIBRES (EMPs) particles (EMP) that requires to limit human crocidolite, glaucophane, anthophyllite-asbestos, antigorite, palygorskite, exposure. Most challenging. tremolite-asbestos, talc, minnesotaite, and actinolite-asbestos sepiolite

2 adapted from TAP (2018) 361, 185 Antigorite

MONOCLINIC OR ORTHORHOMBIC

Modulated wave-like 1:1 layer, with polarity inversion every half wavelength (Capitani and Mellini, 2004)

Chemical composition deviates from that of the other serpentine minerals, because of

discrete Mg(OH)2 loss

The variable modulation gives rise to a polysomatic series, with general formula:

M3m-3 T2mO5m(OH)4m-6 where m is the number of tetrahedra within a wavelength (Mellini et al., 1987; Otten, 1993) 3 May we define antigorite asbestiform?

Fibrous Antigorite from Rowland Flat area, Barossa Valley, South Australia (Keeling et al., 2008) 4 May we define antigorite toxic?

«Currently there is a limited number of in vitro and in vivo toxicological investigations performed on lamellar and fibrous antigorite and the results of the studies are not conclusive on antigorite toxicity.»

The New Caledonia

7 modified after Cluzel et al., 2001 Asbestos assessment in New Caledonia

1994 First evidence of environmental exposure to asbestos (Luce et al., 1994)

The government of NC launches a surveillance program to evaluate the 2005 potential professional exposure to asbestos.

Ban of the use of asbestos (Arrêté n° 2007-767/GNC) 2007 First geological survey of potentially NOA occurrences in ultrabasic units

Promulgation of the decree concerning the protection of workers against risks arising from 2010 asbestos exposure (Délibération n°82 du 25 août 2010)

Epidemiological correlation between mesothelioma and environmental exposure to 2011 fibrous serpentine minerals (Baumann et al., 2011)

Introduction of a protocol for best practises in mining sites to prevent and manage 2015 asbestos pollution (Guide des bonnes pratiques minières) 8 Environmental exposure to NOA

DOMESTIC EXPOSURE Melanesian houses are covered with raw earth and tremolite-Pö whitewash.

Quenel, Cochet (2001)

Baumann (2010) 9 Environmental exposure to NOA

ENVIRONMENTAL EXPOSURE

Lahondère (2007) «Malignant Mesothelioma (MM) in New Caledonia is associated with the presence of fibrous serpentine»

10 Hiengène, Tendo tribe from Lahondère, 2007 Mapping of NOA occurrences DIMENC/SGNC-BRGM

12 Occupational exposure to NOA

Ni-ore exploitation from lateritic deposits

3 mining industry Koniambo-KNS 23 open mines

Tontouta mine

Doniambo-SLN Goro-VALE NC

13 NOA occurrences in lateritic units

14 modified after Lahondère, 2012 Under humid sub-tropical conditions, natural deposits of asbestos shall be subjected to a stronger pedogenic alteration

Mont Dore, NC NOA occurrences in lateritic units

P Antigorite Tremolite E D O G E N I C

A L T E R A T I O N 16 Sevin et al., 2014 The asbestos regulation in New Caledonia

 Antigorite in the list of the regulated-asbestos

 No discrimination between antigorite and fibrous/asbestiform antigorite

 No analytical method for the identification and quantification of fibres

 No indication about environmental exposure was provided

17 Mining companies risk-management

defines how to measure the likelihood of exposure RISK EXPOSURE Exposure x Hazard

HAZARD

defines what makes a mineral fibre hazardous

Guide des bonnes pratiques minières en matière de gestion du risque amiante environnemental, 2015 18 Mining companies risk-management

19 Guide des bonnes pratiques minières en matière de gestion du risque amiante environnemental, 2015 General strategy for risk evaluation in a natural site

in the frame of the HAZARD evaluation, we need to define  the properties of a fibrous mineral that have an impact on human health  the metrics (aspect ratio, crystallochemistry, persistence, …)

in the frame of EXPOSURE assessment, we need to define  standard methods and classifications → Geological NOA-risk model

20 Macroscopic features of Caledonian antigorite

An evident lack of cohesion and a very altered appearance characterized the NC rock-fragments.

Most of antigorite displays a silky FIBRO-LAMELLAR SHAPE

21 Petriglieri et al. - accepted Optical investigation: textural appearance

Star- and fan- shaped blades Interpenetrating texture

Antigorite samples show a greater types of shapes and intergrowths

lath-shaped lamella fibrous-lamellar blade Even the same sample can display the co-existence of several different textures

22 Petriglieri et al. - accepted SEM images: morphological aspect

FIBRO-LAMELLAR

ANTIGORITE Antigorite has the form of fibro-lamellar crystals with regular or irregular endings

Lamellar antigorite gradually cleaves in fibrous like particles, assuming a fibro-lamellar habit

23 Petriglieri et al. - accepted SEM images: morphological aspect

low-altered high-altered

bundles of fibrous particles with splaying ends lamellar-bladed elongated particles 24 Intergrowth of serpentine phases

Antigorite

25 Petriglieri et al., 2019 Intergrowth of serpentine phases

Raman peaks in OH-stretching region confirm the intergrowth of fibro-lamellae of antigorite and compact bundle fibres of chrysotile

Petriglieri et al., 2015; 2019 26 Finely intergrowth of antigorite and chrysotile

Chrysotile ?

27 Finely intergrowth of antigorite and chrysotile

59 spot analyses have been acquired, pointing the laser beam on various fibro- lamellar particles and contact areas with Atg each other

All OH stretching peaks generally attributed to antigorite and chrysotile co-exist together in a complex “doublet”

28 Finely intergrowth of antigorite and chrysotile

TEM confirmed the double nature of this sample, which consists of the intimate intergrowth of fibrous antigorite and chrysotile fibres Antigorite at the micro-scale

Chrysotile 29 Which properties make asbestos hazardous?

PATHOGENIC PROPERTIES OF ASBESTOS

Fibrous habit asbestos fibres penetrate deeply into the lung. Long (> 5 m), thin (< 3 m) and high-aspect ratio (length/diameter  3) are pathogenic; a long and thin fibre is more dangerous than a short and thick one (Stanton’s hypothesis, 1981). macrophage recruitment High biopersistence clearance once in the lung, asbestos fibres are not dissolved and frustrated phagocytosis may stay within the lung for decades. They are not inhaled macrophage efficiently cleared out by macrophages, elicit fibre activation inflammation and may eventually translocate to other inflammatory factors organs. death of macrophage

Surface reactivity Membranes asbestos fibre surface is chemically reactive and can damage biological media or living cell, altering cellular

basal metabolism. Particle and cell derived Enzymes ROS (reactive oxygen species)

DNA

30 Old and new approaches (e.g., Gualtieri, Mossmann, Roggli, EMU Notes, 2018 - https://doi.org/10.1180/EMU-notes.18) Evaluation of potential toxicity of fibrous antigorite

P E EXPERIMENTAL DESIGN D O  Physico-minero-chemical G characteristics E N  Cell-free chemical reactivity I  Cellular toxicity C

A L T SAMPLES E  3 fibrous Atg (NC) R A  non-fibrous Atg T I  negative CTRL (MMVF) O N  positive CTRL (UICC Ctl)

31 Comparing differently altered antigorite samples non-fibrous Atg low-altered

WHO (1997) COUNTING CRITERIA

Length > 5 μm Diameter < 3 μm Aspect ratio ≥ 3:1 mid-altered high-altered

Amount of respirable fibres is similar (30-40%) for all the alteration status

32 First results on antigorite toxicity

low-altered mid-altered high-altered non-fibrous chrysotile MMVF

MH-S A549 MH-S A549 MH-S A549 MH-S A549 MH-S A549 MH-S A549 Cytotoxicity - - * ** ** ** - - ** ** - - ROS generation - - - ** * - - - ** * - - GSH stress depletion - - ** ** ** ** - - ** ** - - PPP inactivation ------** ** - -

Oxidative HO-1 induction - - - * - - - - ** ** - - NO production - - ** ** ** ** - - ** ** - -

TNF-α

production - - - - ** - - - ** - - - Inflammation DNA nd nd nd nd nd nd damage - * * - ** - Lipid

damage peroxidation - - - * - * - - * * - - 33 Biomolecule First results on antigorite toxicity

low-altered mid-altered high-altered non-fibrous chrysotile MMVF

Oxidative HO-1 induction - - - * - - - - ** ** - - NO production - - ** ** ** ** - - ** ** - -

TNF-α

production - - - - ** - - - ** - - - Inflammation DNA nd nd nd nd nd nd damage - * * - ** - Lipid

damage peroxidation - - - * - * - - * * - - 34 Biomolecule Comparing with chrysotile pathogenicity

LDH (cell death) Cytotoxicity increases with alteration of antigorite. Altered antigorite samples are less cytotoxic than Ctl chrysotile ** high-altered **

* * mid-altered * Cytotoxicity relies non-fibrous Atg on fibre surface low-altered MMVF chemistry

35 General strategy for risk evaluation in a natural site

in the frame of EXPOSURE assessment, we need to define  standard methods and classifications → Geological NOA-risk model

36 Geological NOA-risk management

Robust asbestos-oriented geological model

Reliable sampling strategy

NOA quantification

NOA-risk identification

37 Field survey on Tontouta mining front

Cr mine

Ni-ore

38 Geology and petrography of Ni-ore site

Red-limonite with Mn-oxides. Image Serpentinized harzburgite (saprolite) removed

Sector 13 _ Ni content: 1.92 wt% Image removed

(fibrous) antigorite Harzburgite (dunite?) 39 Geology and petrography of Ni-ore site

Red-limonite with Mn-oxides. Image Serpentinized harzburgite (saprolite) removed

Sector 13 _ Ni content: 1.92 wt% Image removed

(fibrous) antigorite Harzburgite (dunite?) 40 Take home messages

Unaltered non-fibrous antigorite is not active in any toxicological assay investigated.

Caledonian antigorite exhibits a fibro-lamellar habit, resulting in a greater variability in texture and morphology.

Pedogenic alteration of NOA affects the potency to disperse fibers into the environment.

Altered fibrous antigorite shares with chrysotile key physico-chemical features and toxic effects in vitro.

NOA alteration modifies the cell toxicity of antigorite suggesting a role of surface chemistry in the potential pathogenicity of fibrous antigorite. Thanks to all partners

Supporter and funder of UniTO – “G.Scansetti” Center ISEA Laboratory - UNC UniPR the «Amiante et Bonnes Francesco Turci Christine Laporte-Magoni Emma Salvioli Mariani Pratiques» project Maura Tomatis Monika Le Mestre Danilo Bersani Elena Gazzano Nahza Salmaoui-Folcher Mario Tribaudino Chiara Avataneo Peggy Gunkel-Grillon Elisabetta Aldieri Roberto Cossio Roberto Compagnoni Société Minière Montagnat Bice Fubini CNR-IGG UniMIB Fabrizio Piana Alessandro Cavallo Luca Barale Thank you!