National Toxicology Program experimental studies

The assays specificity and sensitivity is determined by using human samples spiked with the HCA-adduct and experimental models (i.e., rodents), fed known doses of the HCA of interest. Spiked human samples are used because HCAs are very potent mutagens and because some specific HCAs have been classified as reasonably anticipated to be human carcinogens by the National Toxicology Program. Therefore human studies involving voluntary exposure to purified HCAs are prohibited. 

Chronic inhalation exposures to indium compounds can induce pulmonary toxicity and carcinogenesis in experimental animals. Indium (III) phosphide (IP) was chosen by the National Toxicology Program (NTP) for chronic toxicity studies due to its widespread use in the microelectronics industry and its potential for chronic exposure to workers (NTP 2001). Inhalation exposures of rats to IP at doses of 0, 1, 3,... 

Studies on experimental animals have indicated its tumorigenic potency. Repeated inhalation of dimethyl snlfate vapors cansed tumors of nasal cavity and thorax in rats. Repeated subcutaneous injections of the liq-nid produced local sarcomas. In hnmans, however, its carcinogenicity has not been established. The U.S. National Toxicology Program has classified this componnd as Reasonably anticipated to be carcinogenic to human (NTP 1998). 

Chadwick A. Tolman received his Ph.D. in physical chemistry from the University of California at Berkeley and until recently was a program officer in organic and macromolecular chemistry in the Division of Chemistry of the National Science Foundation. He is now a staff officer at the National Research Council Board on Environmental Studies and Toxicology. He has extensive experience and expertise in chemistry and chemical process development. Dr. Tolman spent 31 years in Central Research at the DuPont Experimental Station. His work has spanned a broad range of subjects, including hydrocarbon oxidation, organometallic chemistry, and the destruction of toxic organic compounds in wastewater. 

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