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Evaluation of Health Hazard of Amorphous Silica-Coated Cristobalite Following Intratracheal Injection in Rats.

PB92220573

Publication Date	1973
Personal Author	Johnson, G. T.; Lewis, T. R.; Groth, D. H.
Page Count	16
Abstract	The subchronic toxicity of industrial silica (7631869) dusts was studied. Dusts collected in baghouses of a metallurgical facility consisted of silica coated cristobalite (14464461) particles. Adult albino-rats were injected intratracheally with saline suspensions of 10 milligrams of silica dusts or quartz dusts as a positive control. Animals were observed daily for appearance, mortality, and behavior. Pulmonary lymph nodes, lungs, and spleens were examined histologically at 3, 6, and 9 months post treatment. Gross and splenic observations were negative. Granulomatous pulmonary inflammatory lesions with crystalline particulate inclusions were observed in both silica and quartz exposed animals after 3 months. Collagen content of the lesions was greater at 6 months, and at 9 months a reduction in the number of cells in the granulomas was observed. Silica dust and quartz induced lesions were very similar. The authors conclude that siliceous dusts have the potential for producing granulomatous pulmonary lesions in humans. They recommend that engineering controls be installed and that threshold limits for exposure be based on existing quartz exposure limits.
Keywords	Cristobalite Health hazards Silicon dioxide Trachea Dust Rats Occupational exposure Metallurgy Lymph nodes Spleen Lung Histology Granuloma Pneumonia CAS 7631-86-9 CAS 14464-46-1
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	57Y - Toxicology 57U - Public Health & Industrial Medicine 94D - Job Environment 41I - Job Environment
Corporate Authors	National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
NTIS Issue Number	199223

Evaluation of Health Hazard of Amorphous Silica-Coated Cristobalite Following Intratracheal Injection in Rats.

Evaluation of Health Hazard of Amorphous Silica-Coated Cristobalite Following Intratracheal Injection in Rats.
PB92220573

Publication Date	1973
Personal Author	Johnson, G. T.; Lewis, T. R.; Groth, D. H.
Page Count	16
Abstract	The subchronic toxicity of industrial silica (7631869) dusts was studied. Dusts collected in baghouses of a metallurgical facility consisted of silica coated cristobalite (14464461) particles. Adult albino-rats were injected intratracheally with saline suspensions of 10 milligrams of silica dusts or quartz dusts as a positive control. Animals were observed daily for appearance, mortality, and behavior. Pulmonary lymph nodes, lungs, and spleens were examined histologically at 3, 6, and 9 months post treatment. Gross and splenic observations were negative. Granulomatous pulmonary inflammatory lesions with crystalline particulate inclusions were observed in both silica and quartz exposed animals after 3 months. Collagen content of the lesions was greater at 6 months, and at 9 months a reduction in the number of cells in the granulomas was observed. Silica dust and quartz induced lesions were very similar. The authors conclude that siliceous dusts have the potential for producing granulomatous pulmonary lesions in humans. They recommend that engineering controls be installed and that threshold limits for exposure be based on existing quartz exposure limits.
Keywords	Cristobalite Health hazards Silicon dioxide Trachea Dust Rats Occupational exposure Metallurgy Lymph nodes Spleen Lung Histology Granuloma Pneumonia CAS 7631-86-9 CAS 14464-46-1
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	57Y - Toxicology 57U - Public Health & Industrial Medicine 94D - Job Environment 41I - Job Environment
Corporate Authors	National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
NTIS Issue Number	199223