: Bellmann, B.; Muhle, H.; Ernst, H.

Abstract
Published ip injection studies have shown different biological behaviour of different sepiolite samples. There was no evidence for carcinogenic potential of sepiolite from Vicalvaro, Spain, whereas a high tumor incidence was reported for sepiolite from Finland. The low biological activity of sepiolite from Vicalvaro, compared to the Finnish sample, could be caused by low in vivo persistence or by the short length of the fibers, or both. In this study a further sepiolite sample, obtained as a commercial sample originating from China, was investigated. This sample contained a higher fraction of fibers longer than 5 um, comparable to the Finnish sepiolite sample. The fraction of fibers with a length >5 um was 0.12 and 2.2% for the Vicalvaro and Chinese sepiolite, respectively. (Abstract truncated)