Asbestos is a ubiquitous construction material with a wide variety of uses including: thermal insulation in buildings, general fire protection and the lining of brake pads. There are several forms, the most common of these being blue (crocidolite), brown (amosite), white (chrysotile) and rarer forms include, tremolite, athophylite, actinolite.
Inhalation of asbestos fibres, especially crocidolite, is associated with lung disease (asbestosis, lung cancer and mesothelioma). Due to the hazardous nature of asbestos there is a need to determine whether asbestos is present in the environment - in traffic-heavy urban areas, old buildings, during demolition work etc.
Light microscopy is a key tool in the examination of environmental examples. It is able to determine the presence, type and preliminary size distribution of asbestos fibres in a given volume of sample.
Sample analysis usually commences with stereo microscopic examination of the bulk sample to determine the presence of asbestos fibres. Fibres can be further identified using polarizing microscopy. The quantity and size distribution of fibres is then analyzed by phase contrast microscopy, as certified by regulatory bodies and can be aided by image analysis software. Digital imaging technology enables records and audit trails to be kept for each analysis.
Key microscopy techniques in asbestos imaging include: stereomicroscopy, polarizing microscopy, phase contrast, image analysis, digital imaging