Some
clay minerals occur naturally in a fibrous or lath-like crystal state as
attapulgite and
sepiolite. Because of their sorptive and colloidal properties,
attapulgite and
sepiolite have numerous industrial applications, mainly as additives in oil-drilling muds, in chemical
fertilizers, pesticides, paints, adhesive products,
bleaching agents, cosmetic compounds and phytosanitary products. World consumption of each is over one million tons annually.
Acid-treated
attapulgite is used in the composition of certain drugs used for the treatment of
gastrointestinal diseases. Such drugs available commercially in France were analysed for their
mineral content by transmission electron microscopy and found to contain
attapulgite fibres [mean length: 0.9 micrometers (0.1-3.6); mean diameter: 0.05 micrometers (0.01-0.5)]. The haemolytic activities of a Spanish
attapulgite sample and of three samples of drugs sold in France were greater or similar to that of UICC
chrysotile asbestos.
Attapulgite fibres were encountered in large quantities in the lung washing fluid of a patient suffering from lung
fibrosis who had been exposed recently for three years during the processing of
attapulgite material.
Attapulgite fibres were also found in a urine sample from a patient who had ingested 6-9 g/day of an
attapulgite drug for six months.