Document oJXXrrD9Zrg23O2zoVkQpmZr

14256997033 2002-02-26 19:09:21 (GMT), page 10 9 of crocidolite in a smaller percentage of miners from Thetford (13 vs. 71 percent). (Nayebzadeh et al. 2001) Nayebzadeh et al repeat the assertion that the crocidolite in the lungs ofAsbestos miners came from exposures to imported crocidolite used in the gas mask manufacture. However, they overlook the fact that if crocidolite was used, it was only during the time from 1939-1941, and about half ofthe workers in their study began working after 1941. They offer no explanation for the crocidolite in the Thetford miner's lungs. The most likely source ofthis crocidolite was the local mine ore, not imported fibers. Two geological surveys found that mines from both areas contained blue fibrous reibeckite otherwise known as crocidolite. (De 1961;Rejean Hebert 2002;Hebert and R 1980;Hebert R 1980) How did the QAMA-McGill researchers miss this information on crocidolite contamination of ore? The QAMA was given the De PhD thesis in 1960 and the McGill research team cited the thesis in 1972.(Gibbs and LaChance 1972) However while noting that De found actinolite in the Canadian mines, they omitted any mention of his twelve-page discussion ofthe crocidolite contamination ofthe mine ore body. Over two decades later in 1995, Dufresne and others extracted and published considerable information from the De thesis: "There are very few data studies on concentrationoftremolite in the ore body except that from the PhD thesis entitled ` Petrology of dikes emplaced in the ultramafic rocks of south eastern Quebec' of Dr. De deposited in 1961 at Princeton University. The objective of the thesis was to study the dike rocks and their relation to the ultramafic rock in the Eastern Townships. It appears that the concentration ofamphiboles in the rocks are variable and can be substantially high in some dikes of granitic and dioritic composition. For instance, he reported the 9