Investigation of the permanence of cellulose fibres in rats lungs

Status:

completed 09/1995

Aims:

The classification of certain fibre-like dusts depending on fibre shape and biodegradability; suspicion that, according to these criteria, organic fibres also possess carcinogenic potential. Cellulose fibres are used in the paper and insulating material industries as well as for improvements to surfaces (flock-coating). Goal: animal tests to determine the biodegradability of cellulose fibres; evaluation of carcinogenic potential

Activities/Methods:

Endotracheal instillation of two different cellulose fibre preparations (pure hardwood cellulose as the model substance and the commercial product "isofloc"); tracing the elimination of the fibres over a period of one year

Results:

The fibre dimensions L/D of the test substance are 7.7/0.45 µm, the model substance 4.2/0.87 µm. Both types of fibres were still present in the lung after one year, the pure cellulose fibre was unchanged. The decay periods were calculated as 1,000 days (pure cellulose) and 72 days (isofloc). With isofloc an unexplainable splitting into thinner fibres was observed.

Publications:

Muhle u.a.: Investigation of the durability of cellulose fibres in rat lungs. Ann.occup.Hyg. Vol. 41 (1997) S. 184-188

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