Silicosis Caused by Rice Husk Ashes

Abstract

Silicosis Caused by Rice Husk Ashes: Shuchun Liu, et al. School of Public Health, Harbin Medical Univeraity—The processing of rough rice (paddy) can produce rice husk which is about 20% of paddy. Rice husk is utilized as an energy resource in many countries. Rice husk ash is used to a great extent as an industrial raw material in the ceramic and metallurgical industries. A number of workers are exposed to rice husk ash dust. Whether rice husk ashes can cause pneumoconiosis and other adverse effects is still a problem awaiting solution. In this connection, we performed epidemiological, experimental and aetiological studies. Rice husk ash dust can cause silicosis characterized by diffuse interstitial fibrosis and nodules. The free silica content increased as the treatment temperature for rice husk rose, and so did cristobalite and tridymite content. When rice husk was treated at 1,300°C, free silica content amounted to 93.8%, of which cristobalite was 38.0% and tridymite 6.1%. These products are the main agents in the development of diffuse pulmonary fibrosis and silicotic nodules.