Environmental exposure silica dust

Total frequencies of environmental illness are difficult to measure. When causes can be identified, however, scientists observe that frequencies of occurrence of a particular illness vary directly with the severity and extent of exposure. Particularly frequent in the workplace are skin lesions from many different causes and pulmonary diseases related to the inhalation of various dusts, such as coal dust (black lung), cotton dust (brown lung), asbestos fibers (asbestosis), and silica dust (silicosis). Environmental agents can also cause biological effects without overt clinical illness (for example, chromosome damage from irradiation). 

The health and environmental issues for nanoclays specifically are rninimal and manageable. Sister organoday products have been used for many years in a host of industrial and consumer products. The perception that nanoclays are somehow different because of the prefix nano may be the problem. Nanoclays only become nano when they are placed in a host-polymer matrix, whereupon they cannot be separated or distinguished form the bulk polymer and other constituents. Crystalline silica is a naturally occurring component that may be present in commercial alkyl quaternary ammonium bentonite (CAS No. 68953-58-2) at concentrations <0.5% [8]. Crystalline silica dust (see also Chapter 19) when inhaled is a health hazard in humans and is regulated to very low permissible exposure limits. 

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