Controversy continues to surround the biological activity of short fibre chrysotile. This is largely due to a lack of studies in which there has been 'pure exposure' to this material. Most of the exposures studied, whether in humans or animals, have been confounded by the additional presence of long fibre chrysotile and/or amphibole. This report presents the morphological and morphometric findings of a lifetime inhalation study of F344 rats exposed to three types of chrysotile. The first, from Coalinga, Calif., is comprised of fibres that are almost all less than 5 μm in length and is not contaminated with amphibole. The other two, the Jeffrey fibre and the UICC/B standard, are both Canadian long fibre preparations with a minor degree of amphibole contamination. Exposed animals displayed no fibrosis following exposure to Coalinga chrysotile but showed fibrogenic responses with both Canadian fibres.

Lithium as an essential element for human life is still a subject of controversy. However, it is accepted that it does have profound neurological effects and is a valuable treatment for bipolar disease. Generally, it occurs in barely trace amounts in groundwater with few major exceptions. One of these is the Northern area of Chile where all potable water and many of the food stuffs contain high levels of lithium; between 100 and 10,000 times higher than most rivers in North America. Inevitably, the local population has been exposed to these levels in their drinking water for as long as the region has been populated. The present report details lithium levels in all the surface water sources of Northern Chile with comparison to that elsewhere. The implications for the local population are discussed and their situation compared to those exposed to other sources of lithium pollution.

Lithium, generally, occurs in barely trace amounts in ground water with few major exceptions. One of these is the northern area of Chile where all potable water and many of the food stuffs contain high levels of lithium. Surface water can contain between 100 and 10,000 times more than most rivers in North America. Inevitably, food, both animal and vegetable, contains higher lithium levels than found elsewhere. In consequence, the local population has been exposed to high levels of lithium in their food and drinking water for as long as the region has been populated. The present report details lithium levels in a variety of food stuffs from several locations in Northern Chile and compares these with those found elsewhere. The implications for the local population have been discussed in our earlier paper.

Asbestos is a commercial term referring to 6 fibrous minerals from 2 mineralogical classes: serpentine and amphibole. Chrysotile, or white asbestos, is the only serpentine mineral. The asbestiform habit of amphibole asbestos is far more toxic than chrysotile. However, most amphibole minerals are found in the "non-asbestiform" state that pose few, if any, health risks. Comminution, whether deliberate during crushing or grinding, or incidental in usage may produce structures known as "cleavage fragments" from a wide variety of sources. A considerable body of evidence, gathered over the last 30 years, demonstrates that amphibole cleavage fragments do not show the same toxicity as their asbestiform analogues. Since there still continues to be confusion and controversy on this point, this review is aimed at resolving a major portion of this controversy. It has done so by bringing together the supporting mineralogical, animal and human evidence from many sources. These observations demonstrate that cleavage fragments and amphibole asbestos fibres have fundamentally different properties and these differences are biologically relevant. Indeed, the toxicity of respirable cleavage fragments is so much less than that of the fibrous amphiboles that by any reasonable measure they are not biologically harmful.