Additives for reducing the toxicity of respirable crystalline silica. SILIFE project

Abstract

Prolonged inhalation of crystalline silica particles has long been known to cause lung inflammation and development of the granulomatous and a fibrogenic lung disease known as silicosis . The International Agency for Research on Cancer (IARC) has classified Respirable Crystalline Silica (RCS) in the form of quartz and cristobalite from occupational sources as carcinogenic for humans (category 1) . In this regard, numerous studies suggest t hat the toxicity of quartz is conditioned by the surface chemistry of the quartz particles and by the density and abundance of silanol groups. Blocking these groups to avoid their interaction with cellular membranes would theoretically be possible in order to reduce or even to eliminate the toxic effect . In this regard, t he main contribution of the presented research is the development of detoxifying processes based on coating technologies at industrial scale, since the previous studies reported on literatu re were carried out at lab scale. The results obtained in two European projects show ed that the wet method to obtain quartz surface coatings (SILICOAT project) allows a good efficiency in inhibiting the silica toxic ity, and the preliminary results obtained in an ongoing project (SILIFE) suggest that the developed dry method to coat quartz surface is also very promising . The development of both coating technologies (wet and a dry) should allow these coating technologi es to be applied to a high variety of industrial activities in which quartz is processed. For this reason, a lot of end -users of quartz powders will be potentially benefited from a reduced risk associated to the exposure to RCS.