SEM of wood dust particles

IRG/WP 97-50084

U Schmitt, R-D Peek, A O Rapp

Dust particles from beech and oak trees have been classified in Germany as being "working materials which are definitely carcinogenic to humans". All other wood dusts, including those from softwoods, are classified as being materials "with reasonable suspicion of carcinogenic potential". The carcinogenic principle of action continues to remain unclear. The mechanical irritation is one of a number of possible triggering principles. In this connection the morphology of the dust particles is of decisive importance. With the aid of a scanning electron microscope this study characterises the dust from spruce, Scots pine, beech and oak. With regard to shape and size the dust particles of all sample collections were divided into 5 groups with principle structural similarity. Therefore a different particle morphology with correspondingly different mechanical irritation in the nose can not be the main principle of action. When compared to asbestos fibers, the small amount of fibrous dust particles as one of the five groups could be clearly distinguished by their structure and dimensions. Mechanical irritation as the main principle of action in the formation of malignant nasal tumors is also contradicted by the findings of different working groups which have established a strong association between hardwood dust and adenocarcinomas of the nasal cavity and paranasal sinuses, and a connection between softwood dust and other types of nasal carcinoma.


Keywords: SCANNING ELECTRON MICROSCOPY; WOOD DUST PARTICLES; NASAL CANCER; MECHANICAL IRRITATION

Conference: 97-05-25/30 Whistler, British Columbia, Canada


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