Asbestos

Asbestos and other fibres

 

Potential toxicity of man-made mineral fibres (MMMF)

Refractory ceramic fibers (RCF) are amorphous fibers made up of various metal oxides (Al2O3, SiO2), proposed as asbestos substitutes, and used as high temperature insulation material. When heat-treated, RCF will devitrify, depending upon time and temperature during the service life of the insulation, into crystalline phases (mullite and/or cristobalite). The removal of RCF in industrial furnaces may occasionally cause occupational exposure to respirable crystalline silica.  The Centre investigates the effect of thermal treatments on surface reactivity and biological response to RCFs. Moreover the Centre investigate the effect of other relevant surface modifications (e.g iron coverage) occuring following fiber inhalation.

 

Our bibliography on the subject

Tomatis et al, 2002
Elias et al, 2002 (doi: 10.1080/00984100290071360)

 

Health risk assessment of asbestos fibres in waters

 

Our bibliography on the subject:
Astolfi et al, 2001 (doi….);

 

 

 

Covering, weathering and biodeterioration of asbestos-rich substrates and fallouts on asbestos risk

Asbestos fibers exposed in natural outcrops of serpentinite rocks, in asbestos-rich soils and in asbestos-cement roofs expose their surfaces to physical (e.g. temperature changes, freezing and thawing, washing away by rain and snow melt water) and biological (e.g. rock-dwelling and soil fungi, lichens, plants) forces. Covering of asbestos-rich substrates by plants and lichens significantly limit the dispersion of fibers in the air (2, 6, 7). Weathering (5, 9) and biodeterioration (1, 3, 4, 6, 8) of the fibers determine substantial ion removal which modifies surface reactivity and crystal framework, contributing to their partial inactivation. Accordingly, results obtained from fibers freshly collected and stored in the laboratory do not necessarily apply to naturally occurring asbestos (NOA).

Our bibliography on the subject:

[1] Favero-Longo et al. 2005 (doi:10.1039/b507569f)
[2] Favero-Longo et al. 2006 (doi:10.1080/11263500600756546)
[3] Favero-Longo et al. 2007 (doi:10.1016/j.mycres.2007.01.013)
[4] Turci et al. 2007 (doi:10.1002/chem.200600991)
[5] Favero-Longo et al. 2009a (doi:10.1080/15287390802529864)
[6] Favero-Longo et al. 2009b (doi:10.1016/j.jhazmat.2008.06.060)
[7] Favero-Longo et al. 2009c (doi:10.1656/045.016.0514)
[8] Daghino et al., 2009 (DOI: 10.1111/j.1574-6941.2009.00695.x)
[9] Turci et al., 2009 (DOI: 10.1093/annhyg/mep028)

 

Fungi modify in vitro asbestos fibres

Asbestos rich soils offer a case of environmental concern for the study of the interaction mineral/fungi, which fall in the field of geomicology. Soils rich in toxic and potentially airborne asbestos fibres constitute an exposure hazard. Biogeochemical alteration of the mineral could modify the characteristics of asbestos that are related to its toxicity (fibrous shape, biopersistence, iron content and surface reactivity), suggesting a possible strategy for in situ remediation of asbestos-contaminated soils.
The biodiversity of the fungal communities associated to asbestos rich substrates has been investigated. Some of the isolated fungi are able to mobilize iron and magnesium ions from the mineral in vitro. The amount of ions mobilized depends on the fungal effectiveness but also on the chemical composition and on the surface characteristics of the asbestos used. The weathering in vitro of crocidolite and chrysotile fibres, two kinds of asbestos, by some fungi leads to the blunting of their chemical reactivity and to the decrease of the DNA oxidative damage induced by the fibres.

Our bibliography on the subject:

Martino et al., 2003 (DOI: 10.1002/anie.200390083)

Daghino et al., 2005 (DOI: 10.1002/chem.200500046)

Daghino et al., 2006 (DOI: 10.1021/es060881v)

Daghino et al., 2008 (DOI: 10.1111/j.1574-6968.2008.01239.x)

Daghino et al., 2009 (DOI: 10.1111/j.1574-6941.2009.00695.x)

 

 

Potential toxicity of non-regulated asbestiform minerals

Many morphological, chemical features of non-regulated asbestiform minerals, as well as its chemical, bio-chemical and cellular toxicity, can be studied by comparison to UICC standard asbestos, which toxicity is well established. The importance of this study has to be interpreted in the light of the many non regulated fibres which the population may be exposed to. Asbestiform non-regulated fibres, as balangeroite, carlosturanite, fibrous antigorite and many others, are potentially dangerous for humans? Were the cases of Biancavilla – Italy (Paoletti et al., 2000; Comba et al., 2003) or Capadocia – Turkey (Baris et al., 1987; Selcuk et al., 1999) exposure to non-regulated deadly mineral fibres predictable? The physico-chemical tests set up by our Centre, combined with bio-chemical cellular tests, may be extremely helpful in monitoring and quickly predicting a possible hazard of any newly found potentially dangerous mineral fibres.

Our bibliography on the subject:

Astolfi et al, 2001;
Groppo et al, 2005 (doi:10.1080/15287390590523867);
Turci et al, 2005 (doi:10.1080/15287390590523911);
Gazzano et al, 2005 (doi:10.1080/15287390590523957)
Turci et al, 2009 (doi:10.1093/annhyg/mep028)