Malignant mesothelioma caused by childhood exposure to long‐fiber low aspect ratio tremolite

Abstract

A 41-year-old man was found to have a malignant mesothelioma of the pleura. During childhood in Corsica, he had been exposed at home to chrysotile ore from the Canari mine. Analysis of lung mineral content revealed background levels of chrysotile but an elevated level of tremolite and actinolite asbestos. The latter had a geometric mean length of 3.7 microns, a value considerably longer than we have found for tremolite and actinolite from Quebec chrysotile miners but roughly the same as the mean length of amosite and crocidolite in workers with occupational amphibole exposure. No tremolite or actinolite fibers of length greater than 8 microns microns and width less than 0.25 micron were observed. The mean aspect ratio of the tremolite and actinolite fibers was 7, a value similar to that found in chrysotile miners with mesothelioma but considerably less than the mean aspect ratio of amosite and crocidolite from those with occupational exposure. These data suggest that long-fiber tremolite is a potential mesothelial carcinogen in humans, and that fiber length is more important than fiber aspect ratio in this regard.

Chrysotile and tremolite asbestos fibres in the lungs and parietal pleura of Corsican goats

“…17 This indicates that the tremolite fibres in this case and in the goats may originate from the same source, as their size distribution is very different from that of tremolite fibres detected in lung samples of the general population and of chrysotile miners. 18 The ratio of tremolite and chrysotile concentrations was higher in the above mentioned patients (7.4) than in the goats (1.2).…”

Amphiboles: Environmental and Health Concerns

“…Interestingly, exposures in Turkey also include the use of baby-powder containing tremolite. Considerable quantities of amphibole asbestos have been seen in the lungs of the inhabitants of some areas in Corsica, France because they live in areas with outcropping rocks bearing a very high quantity of asbestiform tremolite (Magee et al 1986;Rey et al 1993; Table 1). However, in the lungs of inhabitants of Basilicata (southern Italy) with similar exposure routes to those in Corsica, lower quantities of these minerals have been found (Pasetto et al 2004b).…”

Commentary on ‘Evaluation of take home (para-occupational) exposure to asbestos and disease: a review of the literature’, Donovanet al.

“…74 Magee found mesothelioma cases associated with levels of asbestos consistent with environmental exposures of chrysotile. 75 Without suggesting a particular fiber type, Magnani concluded, ''[O]ur results suggest that non-occupational exposure to relatively low-doses of asbestos is a hazard that may contribute to the burden of mesothelioma over the next few decades.'' 76 In a previous paper, Magnani studied the exposures at a plant where chrysotile was the main exposure.…”