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ELEMENTAL ANALYSIS OF RESPIRABLE TIRE PARTICLES AND ASSESSMENT OF CARDIO-PULMONARY TOXICITY IN RATS
Citation:
GOTTIPOLU, R. R., E. R. LANDA, J. K. MCGEE, M. SCHLADWEILER, G. WALLENBORN, A. D. LEDBETTER, J. E. RICHARDS, AND U. P. KODAVANTI. ELEMENTAL ANALYSIS OF RESPIRABLE TIRE PARTICLES AND ASSESSMENT OF CARDIO-PULMONARY TOXICITY IN RATS. Presented at American Thoracic Society Annual Meeting, San Francisco, CA, May 18 - 23, 2007.
Description:
Elemental Analysis of Respirable Tire Particles and Assessment of Cardio-pulmonary Toxicity in Rats
R.R. Gottipolu, PhD1, E. Landa, PhD2, J.K. McGee, MS1, M.C. Schladweiler, BS1, J.G. Wallenborn, MS3, A.D. Ledbetter, BS1, J.E. Richards, MS1 and U.P. Kodavanti, PhD1. 1NHEERL, US EPA, RTP, NC, United States; 2US Geological Survey, Reston, VA, United States and 3UNC, Chapel Hill, NC, United States.
Particulate matter (PM) from vehicular traffic has been associated with adverse cardiopulmonary health. Brake and tire components contribute to traffic PM. We hypothesized that injury from respirable tire PM will be dependent upon presence of transition metals and their water solubility. Two types of commercially available, mechanically ground tire materials (T1 and T2) were used. Respirable fractions (<2.12 µm) were separated by air elutriation. Metals from water- and 1M HCl-leachable fractions were analyzed using ICP-AES. Both tire PMs contained a variety of elements; aluminum, copper (Cu), iron (Fe), silica and zinc (Zn) were predominant. Water-leachable metals were lower than acid-leachable in both tire PMs. T2 contained more water-leachable Cu, Fe and Zn than T1. Saline or saline-suspended T1 or T2 (5 mg/kg body wt) were intratracheally (IT) instilled in 12-14 wks old male Wistar Kyoto (WKY) rats. Pulmonary toxicity and cardiac enzymes, sensitive to oxidative stress, were analyzed 1d, 1wk or 4 wks later. Both PMs induced pulmonary injury (T2>T1) 1d post IT. BAL fluid (BALF) neutrophils increased 13 fold with T1 and 27 fold with T2. Eosinophils increased in BALF (T2>T1) whereas macrophages did not. T2 but not T1 increased BALF protein, LDH, and ãglutamyl transferase activities. Most changes in pulmonary markers reversed by 1 wk. No consistent changes in cardiac cytosolic superoxide dismutase and aconitase or mitochondrial isocitrate dehydrogenase and cytochrome oxidase activities were observed. In conclusion, tire PM contained a variety of transition metals and the pulmonary toxicity appears to be dependent upon the quantity of leachable metals. Funded By: This abstract does not reflect US EPA policy. Supported in part by UNC/EPA CT829471 and NRC Research Associateship Award at NHEERL, EPA