Occurrences and Biological Effects of Sepiolite and Palygorskite

抄録

The palygorskite and sepiolite occur widely in marine and non-marine sediments and in the oceans. Geological situation of these minerals insedimentary basins are reviewed. They are considered to be generated in logoon, shallow lacustrine playa which are formed during the last part of drying process of Mgrich and pH lakes or seas. Hence, these minerals are believed to be good palaeoclimatic indicators.
Since it is currently believed that fibrous minerals are potentially active to induce mesothelioma, several clay minerals were tested for their cytotoxicity in vitro using an established cytotoxicity assay. However, it is difficult to evaluate the cytotoxicity and hemolytic action of clay minerals for a number of reasons, because of the presence of variable amounts of impurity in clays, e.g. quartz or cristobalite. The crytotoxicity of the clay minerals in vitro may not accurately reflect their pathogencity in vivo. Our studies of biological effects of pure palygorskite and sepiolite are reviewed to show severe of biological effects of pure palygorskite and sepiolite are reviewed to show severe biological effects of these minerals to rats. With increasing temperature, their toxicity and hemolytic action were reduced. This may be attributed either to structural changes or to the diminution of their surface area.