THE EFFECT OF INGESTION OF DIATOMACEOUS EARTH IN WHITE RATS: A SUBACUTE TOXICITY TEST.
Abstract The effects of 5% diatomaceous earth in the diet fed to white rats over a 90-day period indicated no mechanical or chemical damage to the tissues. There was no significant increase in the percentage of residual silica in liver, kidneys, and spleens of the test animals. Comparison of weight changes in the 5% group with the control showed a greater weight gain in the 5% test group. Histologic sections of animals fed 3% and 1% diatomaceous earth also showed no damage.
Use of diatomaceous earth for the management of stored-product pests
Diatomaceous earth (DE) is almost pure amorphous silicon dioxide, made up of fossilised diatoms; it acts as an insecticide by absorption of epicuticular lipids and fatty acids, leading to desiccation in arthropods. Numerous DE formulations have been attempted for the management of stored-product pests with good results. DE is persistent in its action, poses few or no pest resistance problems, and it leaves no residue. The efficacy of DE is affected by factors such as: its provenance, temperature, humidity and characteristics of target pests and substrate. Application of DE at currently recommended doses causes changes in bulk density of the grain; however, the use of enhanced DE formulations provides control at much lower doses. Therefore, new formulations of DEs usually include other low toxicity insecticides.
TRIPOLI AS A SOURCE OF SILICOSIS
Tripoli designates a form of silica much used in industry and is a substance possessing peculiar properties which distinguish it from the better known quartz or amorphous silica. The term "tripoli" is itself confusing, since it has been applied to other minerals, such as diatomaceous earth, and special types of limestone. The outstanding sources of tripoli are in southwestern Missouri and southern Illinois. Tripoli is widely described as amorphous, but at least some varieties are crystalline, although the crystals are so minute as to warrant the term "cryptocrystalline." Tripoli, when air dried in lumps, is a light, fine textured, minutely porous rock. Its lightness and porosity in its native state are believed to result from the fact that it is the siliceous skeleton of a mineral which in earlier days was much more compact, owing to the coexistence of limestone. The action of water throughout the ages has leached out