Environ. Sci. Technol. 1984, 18, 330-333
Fed. Regist. 1977, 42 (160). Lipari, F.; Swarin, S. J. J. Chromatogr. 1982, 247, 297, Duprey, R. L.; U.S. Department of Health, Education, and Welfare, 1968, PHS Publication 999-AP-42. Cadle, S. H.; Nebel, G. N.; Williams, R. L. SAE Trans. 1979, 87, 2381. “MVMA Motor Vehicle Facts and Figures’ 82”; Motor Vehicle Manufacturers Association of the Uqited States.: Detroit, MI, 1982; p 26. 1977 Nationwide Personal Transportation Study, US. Department of Transportation, Washington, DC, 1981, Report 5, p 25, and Report 2, p 43.
(18) Ward, D. E.; McMahon, C. K.; Johansen, R. W. “An Update on Particulate Emissions from Forest Fires”; presented at the 69th Air Pollution Control Association Meeting, Portland, OR, 1976. (19) Gerstle R. W.; Kemnitz, D. A. J. Air Pollut. Control Assoc. 1967, 17, 326. (20) Rand, E. 1982, America1 Lung Association Bulletin 68, p 5.
Received for review May 25,1983. Revised manuscript received November 16, 1983. Accepted November 30, 1983.
Influence of Volatility on the Collection of Polycyclic Aromatic Hydrocarbon Vapors with Polyurethane Foam Feng Yout and Terry F. Bidleman”$ Shanxi Medical College, Taiyuan, Shanxi, People’s Republic of China, and Department of Chemistry, Marine Science Program, and Belle W. Baruch Institute for Marine Biology Coastal Research, University of South Carolina, Columbia, South Carolina 29208
Polycyclic aromatic hydrocarbon (PAH) vapor penetration through thin sections of polyurethane foam (PUF) was studied to determine the relationships between sample breakthrough, PAH vapor pressure, and total air volume. Frontal chromatographic movement of fluorene, phenanthrene, anthracene, and pyrene vapors through a PUF bed at high volume airflow was examined. From these fronts, the thickness of foam corresponding to 50% breakthrough was obtained for each compound. This breakthrough point was related to total air volume, and breakthrough volumes (VB) were determined for a 7.5-cm PUF thickness (equivalent to a single field sampling plug). A log-log plot of VB vs. PAH solid phase vapor pressure showed only a rough relationship between the two parameters, but the correlation was much improved (r2 = 0.988) when the subcooled liquid vapor pressure was used. From the frontal chromatograms the number of theoretical plates (N) in the absorbent bed was determined. When V, and N were known, the maximum safe sampling volume at a required collection efficiency was calculated.
Table I. Physical Properties of PAH Used in This Study
Introduction During the past decade, increased concern has developed over the environmental impact of trace organic compounds. Polycyclic aromatic hydrocarbons (PAH) have received much attention in studies of air pollution because some of these compounds are highly carcinogenic. Since they are produced by inefficient combustion of carbonaceous material, they occur frequently in the environment from both natural processes and anthropogenic emission. In order to understand their influence on the health of human beings, monitoring of the concentration of these compounds in ambient air is necessary. Most investigations of airborne PAH have been confined to particles collected on glass fiber filters. However, recent studies (1-7) have shown that the three to four ring PAH are largely in the vapor phase because of their volatility and are therefore not retained by filters. A wide variety of adsorbents have been used to sample organic vapors. Since polyurethane foam (PUF) is easy to handle in the field and has good airflow characteristics, it is a commonly used adsorbent for collecting pesticide and PCB vapors and has recently
been investigated for PAH vapor collection (3, 5-7). Quantitative collection of volatile compounds using adsorbents requires a knowledge of the maximum safe sampling volume to prevent breakthrough. The purposes of our study were to (1) determine breakthrough volumes (VB) for three and four ring PAH on a PUF column, (2) relate VB to PAH vapor pressure, and (3) evaluate the collection efficiency of a PUF column for PAH vapors from a knowledge of VB and the theoretical plate number (N) and predict the maximum safe sampling volume.
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+ Shanxi Medical
3 University
College.
of South Carolina.
330 Environ. Sci. Technol., Vol. 18, No. 5 , 1984
compound
structure
vapor pressure at 20 ‘ C , torr suby ~ p , solid cooled C (10) liquid
fluorene
116 3.2 X 10-4
phenanthrene
101 6.2 X 4.0 X 10-5 10-4
anthracene
216 3.2 X 10-6
3.0 X 10-4
1 5 6 2.4
5.6 X 10-5
pyrene
a
X
10-6
3.0 X 10-3
Experimental Section Compounds. Fluorene (FL), phenanthrene (PH), anthracene (AN), and pyrene (PY) were obtained from Eastman Kodak Co. or Aldrich Chemical Co. These PAH were selected for this study because they are common low molecular weight PAH found in ambient air. Also, their vapor pressures have been recently measured at close t o ambient temperatures (10) (Table I). Procedure. The sampling train used for the laboratory study consisted of a PUF prefilter, a mixing chamber for PAH vapors, and a collection column packed with 15 1cm thick X 7.8 cm diameter PUF plugs (density = 0.022 g/ cm3). The apparatus was originally used to study the penetration of organochlorine vapors through a PUF
0013-936X/84/0918-0330$01.50/0
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column (8,9).Construction and operation details and the preparation method for PUF plugs are given in these reports. Air was pulled through the train at about 0.5 m3/min, and sample vapors were continuously bled into the mixing chamber by a slow flow of air through a column containing glass beads coated with approximately 150 mg of the compounds of interest. Experiments were carried out at 20 f 1"C. A soap bubble meter was used to monitor the flow rate through the bead column. The pressure drop across the system was measured with a Magnehelic gauge (Dwyer Instrument Co.) and was related to the high volume airflow using an orifice calibrator. At the termination of the experiment, the 1-cm PUF plugs were individually Soxhlet extracted with petroleum ether, and the extracts were analyzed by using a Packard 3700 series gas chromatograph and flame ionization detection. Analyses were carried on a 180 cm long X 0.4 cm i.d. glass column packed with 3% Dexsil300 on 100/120-mesh Supelcoport (Supelco Co.). Column temperatures (isothermal or programmed operation) were adjusted in the 150-230 OC range to give PAH retention times of 7-15 min. Other working conditions were as follows: carrier gas nitrogen 30 mL/min; detector temperature 250 "C; injector temperature 200 "C. PAH were quantified by peak height. Results and Discussion The quantity of each compound found on individual PUF plugs was expressed as the percentage of the first plug value and plotted against foam thickness to give a frontal
1
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Table 11. Breakthrough Volumes for a 7 . 8 cm Diameter x 7 . 5 cm Thick PUF Column, 20 " C VB, m3
fluorene phenanthrene anthracene pyrene
1.2 x lo2 8.0 X l o 2 1.1 x 103 1.0 x 104
chromatogram. Examples of vapor fronts for PH at different total air volumes and for three PAH at approximately the same air volume (24-h sampling) are shown in Figures 1and 2. From these fronts, the thickness of foam corresponding to the 50% breakthrough point (P-50) was obtained for each compound at a given air volume (Figure 3). These P-50 values were plotted against the total air volume, and a linear relationship between vapor penetration and total air volume was obtained (Figure 4). From Figure 4, VB for any column length can be obtained. For field sampling, we use two PUF plugs 7.8 cm diameter X 7.5 cm thick, so we calculated VB for this foam thickness (Table 11). Previous studies ( 3 , 5 , 7 - 9 , I I ) have shown that vapor penetration through a PUF column is dependent on volatility as well as on total air volume. Figure 2 illustrates this behavior for PH, AN, and PY. Chromatographic theory predicts a linear relationship between log V , and log vapor pressure. However, a plot of these parameters from Tables I and I1 shows much scatter if the solid vapor Environ. Sci. Technol., Vol. 18, No. 5, 1984
331
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Table 111. Theoretical Plate Measurements
N fluorene phenanthrene anthracene -
xis
P-50, cm
5.2 6.3 9.1
7.5 5.1 8.9
6.0
6.0
10.4 4.9 10.2
7.4 4.9 8.2
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0.7 1.2 1.0 1.0 1.4 1.0 1.2
1.1
* 0.2
calculated by using the parameters shown in Figure 6 (16). The N , P-50, and NIP-50 of each frontal experiment are shown in Table 111. These measurements were made for FL, PH, and AN on fronts having P-50 values of about 5 or greater. For PY, penetration was so slight (even at high air volumes) that the fronts were not developed enough for good N measurements. The mean (fs) NIP-50 value was 1.1f 0.2, or approximately one plate per cm of foam. Senum (17)discussed the collection efficiency of solid adsorbent samplers and published a chart relating collection efficiency to N and the sampling volume/retention volume ratio (Vs/ VR). His graph is reproduced here as Figure 7, where we have replaced VR with V,. For VB
Environ. Sci. Technol. 1904, 18, 333-337
Table IV. Maximum Safe Sampling Volumes ( V S ,m 3 ) at Designated Collection Efficiencies' 90% fluorene phenanthrene anthracene pyrene
95%
1.0 x l o 2 6.6 X l o 2 9.2 X 10' 8.2 x 103
'Single plug, 7.8 c m diameter
X
7.7 x 5.0 X 6.9 X 6.2 x
Registry No. FL, 86-73-7; PH, 85-01-8; AN, 120-12-7;PY, 129-00-0.
Literature Cited Cautreels, W.; Cauwenberghe, K. V. Atmos. Environ. 1978, 12, 1133-1141. De Wiest, F.; Rondia, D. Atmos. Enuiron. 1976,10,487-489. Yamasaki, H.; Kuwata, K.; Miyamoto, H. Bumeki Kagaku 1978,27, 317-321. Pupp, C.; Lao, R. C.; Murray, J. J.; Pottie, R. F. Atmos. Environ. 1974, 8, 915-925. Yamasaki, K.; Kuwata, K.; Miyamoto, H. Environ. Sci. Technol. 1982, 16, 189-194. Thrane, K. E.; Mikalsen, A. Atmos. Environ. 1981, 15, 909-9 18. Keller, C. D.; Bidleman, T. F. Atmos. Environ., in press. Burdick, N. F.; Bidleman, T. F. Anal. Chem. 1981, 53, 1926-1929. Simon, C. G.; Bidleman, T. F. Anal. Chem. 1979, 51, 1110-1 113. Sonnefeld, W. J.; Zoller, W. H.; May, W. E. Anal. Chem. 1983.55. 275-280. Billings,'W. N.; Bidleman, T. F. Atmos. Environ. 1983, 17, 383-391. MacKay, D.; Bobra, A,; Chan, D. W.; Shiu, W. Y. Environ. Sci. Technol. 1982, 16 645-649. Banerjee, S.; Samuel, H.; Yalkowsky, S.; Valvani, S. C. Environ. Sci. Technol. 1980, 14, 1227-1229. Chiou, C. T.; Schmedding, D. W. Environ. Sci. Technol. 1982, 16, 4-9. MacKay, D. Environ. Sci. Technol. 1982, 16, 274-278. Reilley, C. N.; Hildebrand, G. P.; Ashley, J. W., Jr. Anal. Chem. 1962, 34, 1198-1213. Senum, G. L. Enuiron. Sci. Technol. 1981,15,1073-1075.
10' 10'
10' 103
7.5 cm thick ( N = 7.5).
defined by the front midpoint, the two chromatographic terms are equivalent (16). When VB and N are known, the collection efficiency of the PUF bed at different air volumes can be predicted from Figure 7. Also, this figure can be applied to predict the maximum air volume for a required collection efficiency. For field sampling we use two 7.8 cm diameter X 7.5 cm thick plugs, so the front plug has N = 7.5. From Figure 7, when N = 7.5 and the required collection efficiency = 95%, vs/ V, = 0.62, or the maximum air volume should be no greater than 62% of VB in order to guarantee that 95% of the vapor has been collected on the first plug of the sampling train. By use of VBvalues from Table 11, maximum safe Vs values have been calculated for the four PAH at 90% (Vs/ V, = 0.82) and 95% (Vs/VB = 0.62) collection efficiencies (Table IV). From these results we can conclude that PH, AN, and PY will be quantitatively collected by two of our field PUF plugs in a 24-h sampling period (-700 m3 air) for ambient temperatures not exceeding 20 OC, in good agreement with field results (7). For sampling PAH vapors at temperatures other than 20 "C, one could calculate Psfrom published vapor pressure-temperature relationships (IO),estimate PLfrom eq 1, determine VBby using Figure 5b, and then use Figure 7 to estimate Vs. Because of its higher volatility, FL is not quantitatively collected for VS = 700 m3. A reduced Vs or a longer trap would be needed to retain FL.
Received for review May 26,1983. Revised manuscript received September 16,1983. Accepted October 5,1983. This work was supported by the US.Department of Energy under the National Environmental Research Park (NERP)Program. Contribution No. 514 of the Belle W. Baruch Institute.
Fractionation, Isolation, and Characterization of Ames Mutagenic Compounds in Kraft Chlorination Effluents Bjarne Holmbom," Ronald H. Voss, Richard D. Mortlmer, and Alfred Wong Pulp and Paper Research Institute of Canada, Pointe Claire, P.Q., Canada H9R 3J9
Mutagenic extracts from kraft pulp chlorination-stage effluents were fractionated, and the distribution of mutagenicity was determined by the Ames test with tester strain TA 100. Most of the mutagenicity was caused by nonvolatile compounds extractable with ethyl acetate. Strong acids accounted for the principal part of the mutagenicity. The mutagenic components could be concentrated to a narrow band by silica thin-layer chromatography and reverse-phase high-pressure liquid chromatography. The results provide further support for the conclusion that the previously identified hydroxyfuranone (C5H303C1,)is a major TA 100 mutagen in chlorinationstage effluents. The isolation of this compound, its Ames mutagenicity, and some of its chemical properties are described. Introduction
Short-term genetic bioassays are becoming increasingly *Towhom correspondenceshould be addressed at the Laboratory of Forest Products Chemistry, Abo Akademi, SF-20500 Turku 50,
Finland. 0013-936X/84/0918-0333$01.50/0
important tests for the identification of individual compounds or complex environmental mixtures which may pose a potential health hazard (1-3). The best known and most widely used short-term bioassay is the Salmonella microsome assay or Ames test (4) which measures the ability of test samples to induce genetic alterations (mutations) in specially developed strains of Salmonella bacteria. The limitations of this test notwithstanding (e.g., false negatives and positives), it is generally recognized as an important tool for the preliminary screening of potentially mutagenic and possibly carcinogenic chemical substances. Since early 1977, Ames mutagenicity of spent wash liquors from the first (chlorination) stage of kraft pulp bleaching has been the subject of extensive research in several laboratories in Scandinavia (5-11) and North America (12-18). These studies have shown that the Ames mutagenic substances present in chlorination-(C-) stage effluent are primarily direct-acting mutagens causing base substitutions in DNA molecules. They are also fairly unstable at alkaline pH and can be destroyed by reaction with SO2. Whereas kraft C-stage effluents exhibit sig-
0 1984 American Chemical Society
Environ. Sci. Technol., Vol. 18, No. 5, 1984 333
