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Toronto, Canada, 1981; Chapter 4, p 147. (17) Barrette, M.; Lamoureux, G.; Lebel, E.; Lecomte, R.; Paradis, P.; Monaro, S. Nucl. Instrum. Methods 1976,134, 189-96. (18) Lecomte, R.; Paradis, P.; Monaro, S.; Barrette, M.; Lamoureux, G.; Menard, H. A. Nucl. Instrum. Methods. 1978, 150, 289-97. (19) Lecomte, R.; Paradis, P.; Landsberger, S.; Desaulniers, G.; Monaro, S. X-Ray Spectrom. 1981,10, 113-16. (20) Houdayer, A. J.; Beaudoin, P.; Lessard, L. Nucl. Instrum. Methods 1982,202,487-91. (21) Bergioux, C.; Kennedy, G.; Zikovsky, L. J. Radioanal. Chem. 1979, 50, 229-34. (22) Day, J. P.; Fergusson, J. E.; Chee, T. M. Bull. Environ. Contam. Toxicol. 1979, 23, 497-502. (23) Cleroux, R.; Roy, R.; Fortin, N. Water, Air Soil Pollut. 1980, 13,143-56. (24) Gordon, G. E.; Zoller, W. H.; Gladney, E. S. In "Trace Substances in Environmental Health"; Hemphill, D. D., Ed.; University of Missouri: Columbia, MO, 1973; Vol. VII, pp 167-75. (25) Thorton, J. D.; Eisenreich, S. J.; Munger, J. W.; Gorham, E. In "Atmospheric Pollutants"; Eisenreich, S. J. Ed.; Ann Arbor Science: Ann Arbor, MI, 1981; Chapter 14.
(26) Hashimoto, Y.; Osada, Y.; Tanaka, S.; Chiba, R.; Yokota, H.Nucl. Instrum. Methods 1981,181, 227-30. (27) Schuyster, P.; Maenhaut, W.; Dams, R. Anal. Chim. Acta 1978,100,75-85. (28) Hamilton, E. P.; Chatt, A. J . Radioanal. Chem. 1982, 71, 29-45. (29) Penkett, S. A.; Jones, B. M. R.; Eggleton, A. E. J. Atmos. Environ. 1979, 13, 139-47. (30) Lindberg, S. E. Atmos. Environ. 1981, 15, 1749-53. (31) Barrie, L. A.; Georgii, H. W. Atmos. Environ. 1976, 10, 743-49. (32) Barrie, L. A.; Beilke, S.; Georgii, H. W. In "Precipitation Scavenging"; Semonin, R. G., Beadle, R. W., Eds.; EDRA Symp. Ser. No. 41, CONF-741003, National Technical Information Service, 1977, Springfield, VA. (33) MAP3S, "The MAP3S Precipitation Network: First Periodic Summary Report"; Pacific Northwest Laboratory, Richland, WA, PNL-2402, 1977.
Received for review November 22, 1982. Revised manuscript received March 2,183. Accepted March 29,1983. This work has been supported by the Natural Sciences and Engineering Research Council of Canada.
Reaction Rates of Polynuclear Aromatic Hydrocarbons with Ozone in Water Vjera Butkovlb, Leo Klaslnc, Matko Orhanovlb, * and Jasmlna Turk Rudjer BogkoviB Institute, Zagreb, Croatia, Yugoslavia
Hans Gusten"
Kernforschungszentrum Karlsruhe GmbH, Institut fur Radiochemie, 7500 Karlsruhe, Federal Republic of Germany The rate constants for the reaction of pyrene, phenanthrene, and benzo[a]pyrene with ozone in water were determined by means of stopped-flow spectrometry. The second-order rate constants amount to about 4 X lo4, 1.5 X lo4, and 0.6 X lo4 dm3.mol-1.s-1, respectively, over the pH range 1-7. The corresponding half-lives in presence of M ozone at pH 7 are less than a second, i.e., they are 10000 times shorter than the values for pyrene and benzo[a]pyrene that are dissipated widely in the literature. Implications of these results are discussed with respect to the removal of polynuclear aromatic hydrocarbons from drinking water as well as to their atmospheric residence times. Introduction Polynuclear aromatic hydrocarbons (PAH) are ubiquitous in our environment. Many PAH's are known to be carcinogenic to animals and probably to man. Thus, in recent years, a concern has been growing about their release, amount, stability, and fate in the environment ( I , 2). For an ecotoxicological assessment of the PAH's the knowledge of their residence times in the atmosphere and water has become important. Since ozone is commonly used in Europe for the purification of urban drinking water, the half-lives of the PAH's in the reaction with ozone are of importance for an economic ozonation treatment (3, 4 ) . I t is surprising that kinetic data concerning this reaction in water have not been determined as yet. In the related study by Il'nitskii et al. (5) on the ozonation of five PAH's including pyrene and benzo[a]pyrene, it was reported that these compounds at 0.67 X g/mL in acetone and acetoneln-octane solutions completely disappeared from the solution after 2.5 min of 546
Environ. Sci. Technol., Vol. 17, No. 9, 1983
contact with bubbling ozonefoxygen mixtures at 18-21 "C. After only 1 min of contact time the residual amount of the different PAH's was reported to range between 39% and 0%. These data, observed under ill-defined experimental conditions and obtained for a nonaqueous solution with unrealistically high concentrations of both PAH and ozone, were then uncritically taken by Radding et al. (6) to apply for water as the solvent and used to calculate rate constants and half-lives of PAH's at environmentally M in water and 2 relevant ozone concentrations, i.e., X low9M in air. These half-lives for the different PAH's of up to 1 h in water and of several hundred hours in air indicate that such a slow reaction with ozone hardly seems to be an important process for the degradation of the PAHs in our environment (6). Since the authors (6) made an error in the dimension for the rate constant k by using L-mol-l-s-linstead of L.mol-l.min-l, the calculated half-lives in air would actually result in the order of 10OOO h. These calculated half-lives of the PAH's are now dissipated widely in the secondary literature (I,2, 7-9). On the other hand, Hoign6 and Bader reported that the reaction of ozone with organic compounds in water can be very fast (IO). This situation prompted us to start an investigation of reaction rates of PAH's with ozone in water. Experimental Section Kinetic Measurements. Preliminary experiments showed that the disappearance of PAHs with ozone in water is several thousand times faster than the literature data above indicated (5, 7,8). Thus, contrary to the method of Hoign6 and Bader (IO),which determines the reaction rate constant from the consumption of ozone by the solute, we determined the rate constants by monitoring the change of concentration of a PAH in an excess of
0013-936X/83/0917-0546$01.50/0
0 1983 American Chemical Society
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I
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Table I. Rate Constants for the Reaction of PAH's with Ozone for Different H' Concentrations at 25 "C lO-'k, dm3. PAH (concn, mol.dm3) H', M mo1-I.s-l pyrene (2.5 X 10-7 3.9 c 0.5" 4 x 10-4 3.5 0.8 4 x 10-3 3.7 i. 0.7 2x 4.2 f 0.8 4 x 10-2 5.3 f 1.2 3.4 t 0.5 5x 10-1 4.9 ? 0.8 phenanthrene (1.57 X lo-') lo'' 1.57 t 0.01 10-l 1.33 f 0.012 benzo[a]pyrene (7 X lo-') lo'' 0.62 f 0.1 Uncertainties quoted are standard deviations at different [O,], as shown in Figure 2.
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