Based on the predominant content of thin and short asbestos fibres in lung and mesothelioma tissues, it was recently stated (2005) that such fibres 'appear to contribute to the causation of human malignant mesothelioma'. In another study of the same year it was stated that fibres in the order of few microm length and 0.2 microm diameter are the sole able to induce mesothelioma. This scientific conclusions entail some implications from practical point of view. The enormous amount of information gained on asbestos in the last decades is based on the definition of a fibre as an alongated particle with an aspect-ratio of at least 3:1, a diameter < or = 3 microm and a length > or = 5 microm. These parameters were used up today to define occupational and in some case non-occupational limits. In which way can 'reference' values be established if all lengths or only fibres shorter than 5 microm are considered? Nowadays we have no answer. Secondly, assuming a prevalent role of such fibres especially in mesothelioma cases, how can reliable estimates of past exposure obtained in a medico-legal context, since they have never been counted? Morever, how might he the employer responsibility assessed since short fibres were not measured by definition pathogenic, and this not measured, nor were there appropriate filtering systems up to the middle of the '80?
Asbestos-related diseases and microfiber role
PIOLATTO, Pier Giorgio;PIRA, Enrico;ROMANO, Canzio
2006-01-01
Abstract
Based on the predominant content of thin and short asbestos fibres in lung and mesothelioma tissues, it was recently stated (2005) that such fibres 'appear to contribute to the causation of human malignant mesothelioma'. In another study of the same year it was stated that fibres in the order of few microm length and 0.2 microm diameter are the sole able to induce mesothelioma. This scientific conclusions entail some implications from practical point of view. The enormous amount of information gained on asbestos in the last decades is based on the definition of a fibre as an alongated particle with an aspect-ratio of at least 3:1, a diameter < or = 3 microm and a length > or = 5 microm. These parameters were used up today to define occupational and in some case non-occupational limits. In which way can 'reference' values be established if all lengths or only fibres shorter than 5 microm are considered? Nowadays we have no answer. Secondly, assuming a prevalent role of such fibres especially in mesothelioma cases, how can reliable estimates of past exposure obtained in a medico-legal context, since they have never been counted? Morever, how might he the employer responsibility assessed since short fibres were not measured by definition pathogenic, and this not measured, nor were there appropriate filtering systems up to the middle of the '80?
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