ANALYTICAL CHEMISTRY, VOL. 51, NO. 14, DECEMBER 1979
2343
Analysis of Fly Ash from Municipal Incinerators for Trace Organic Compounds G. A. Eiceman, R. E. Clement, and F. W. Karasek" Guelph- Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
Organic compounds present at trace levels were extracted from fly ash samples collected from rnuniclpal Incinerators in Japan, Canada, and The Netherlands. Samples were extracted for 12 h in a Soxhlet apparatus with 200 mL of benzene. The extract was concentrated to 100 p L and analyzed by GC and GC/MS including selected Ion monitoring. Mass spectra were used to assign identities to approximately 100 organic compounds Including polychlorlnated dibenzofurans, polychlorinated dibenzo-p-dioxlns, polychlorinated benzenes, polychlorinated phenols, polycyclic aromatic hydrocarbons, phthalate esters, and aliphatic hydrocarbons. Estimated concentratlons of total organic mass extracted were 1 to 30 pg/g. Polycyclic aromatic hydrocarbons were present at 1 to 500 ng/g of fly ash; the sum of tetrachlorodlbenzo-p-dioxinisomers was an estimated 2 to 10 ng/g.
Incineration of refuse has been an accepted method of solid waste disposal since its inception at the municipal level in 1874 (I). In the incineration process, raw municipal refuse is fed into furnaces a t temperatures between 1OOC-1100 "C and the bulk waste reduced to ash, gases, and noncombustible solids. Inefficient incineration may allow some combustible material to remain unburned. Typically, the principal combustible components of raw materials entering a municipal incinerator include miscellaneous paper, newspaper, plastic, magazine paper, corrugated box board, textile fabric, wood, leather, and rubber ( 2 ) . These refuse products when decomposed in a furnace yield gases such as nitrogen oxides, sulfur oxides, carbon monoxide, water, oxygen, ammonia, hydrogen chloride, and some hydrocarbons ( 3 ) . Such gases emitted during the incineration of municipal refuse generally enter the atmosphere unabated in concentration or volume. Airborne particulates and fly ash may also be released with gaseous emissions and may comprize approximately 20% by weight of estimated total incinerator emissions. These visible, dense airborne particulate and fly ash emissions constitute one of the generally more objectionable aspects of incinerators in urban locations even though little environmental impact data exist for this type of air pollution. Such emissions have been strictly regulated in some European countries and can be reduced through the application of Venturi scrubbers, electrostatic precipitators, cyclone scrubbers, and other devices for similar treatment of incinerator effluent. Most modern municipal incinerators have air pollution abatement equipment which includes electrostatic precipitation for fly ash and other particulate matter. Fly ash consists of between 70-9570 inorganic matter. While trace amounts of elements such as chromium, nickel, copper, zinc, silver, lead, sulfur, phosphorus, and boron have been found, the predominant elements in fly ash are silicon, iron, aluminum, calcium, magnesium, potassium, and sodium. Little information, however, has been published regarding the presence of trace organic compounds in fly ash and airborne particulates generated during incineration of municipal refuse. Hutzinger identified polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and poly0003-2700/79/0351-2343$01 .OO/O
chlorinated phenols in fly ash from municipal incinerators in The Netherlands ( 4 ) and Buser made similar identifications in samples from municipal incinerators in Switzerland ( 5 ) . Additionally, Buser showed that PCDFs may be formed from the pyrolysis of polychlorinated biphenyls (PCBs) which are stable compounds and are widely distributed in the environment (6). A recent study by the Chlorinated Dioxin Task Force of Dow Chemical Company, Michigan Division, indicated that PCDDs are found in widely differing incineration processes including municipal incinerators (71 and a review of this report addressed the serious threat to human health and the environment posed by the presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin in soil, air, and water (8). Polycyclic aromatic hydrocarbons (PAHs), some of which are very toxic, carcinogenic, and mutagenic, were also detected in fly ash from municipal incinerators (9). These published analytical techniques have been developed for the analysis of specific organic compounds or classes of compounds and generally require extensive sample cleanup and handling (7, IO). We report here the characterization of trace organic compounds in fly ash using analytical techniques developed for airborne particulate matter (I I ) involving solvent extraction, gas chromatography, gas chromatography/mass spectrometry, and selected ion monitoring, specifically modified for these analyses. Samples were received from municipal incinerators located in major urban centers in Japan, T h e Netherlands, and Canada.
EXPERIMENTAL Sample Collection and Storage. Canadian fly ash samples were drawn in kilogram quantities from two municipal incinerators located in different urban centers in southern Ontario. Grab samples were collected by the Ontario Ministry of the Environment and provided by Andre Foldes. Both incinerators were operated at temperatures near 900"C and both used electrostatic precipitators. Grab samples of fly ash from Japan were taken from two city incinerators, one located in a heavily industralized area and the other located in a more domestic region of the city. Electrostatic precipitators were used and operating temperatures were 75C-900 "C. These samples were provided by S. Rokushika of the University of Kyoto. The fly ash sample from The Netherlands was provided by Otto Hutzinger of the University of Amsterdam. Samples were stored in closed containers at room temperature and protected from ultraviolet and visible light. Sample Extraction and Concentration. Approximately 20 g of each sample, in medium porosity glass fritted extraction thimbles, were extracted overnight (about 16 h) with 200 mL of benzene ("Distilled in Glass" grade, Burdick and Jackson, Inc., Muskegon, Mich.), in a Soxhlet apparatus. After the first extraction step, each thimble was replaced by a second thimble containing another 20 g of the sample and the extraction continued overnight. Twenty to forty-five milliliters of additional fresh solvent, was added to each Soxhlet apparatus during the transfer step to replace solvent sorbed by the fly ash and lost when the exchange of thimbles was made. Total weighed amounts of fly ash extracted were: Ontario 1 (Ol), 41 g; Ontario 2 ( 0 2 ) ,39 g; Japan 1 (Jl),48 g; Japan 2 (JZ),31 g; and The Netherlands (N), 45 g. The extraction efficiencies of benzene for individual components were not studied in this work, although they are believed to be quite high. Following the extraction step, each benzene extract was concentrated to approximately 5 mL by rotary evaporation at 56-69 0 1979 American Chemical Society
"C under aspirator vacuum. After transferring the sample to a 12-mL centrifuge tube the round bottom flask was rinsed twice with 1-2 mL of benzene and the rinsings were added to the centrifuge tube. Each extract was centrifuged for 5 min a t 3000 rpm to remove solid particles carried over during the extraction and transfer step. The supernatant was transferred to a 25-mL pear-shaped flask and the solid particles remaining in the centrifuge tube were washed with 0.1-0.5 mL portions of benzene during treatment in an ultrasonic bath for 5-10 s and centrifuged as described previously. The washings were added to the supernatant in the pear-shaped flask and the procedure was repeated a second time. After volume reduction to approximately 0.5 mL by rotary evaporation a t 62-66 "C under aspirator vacuum, each extract was transferred to a sample vial. Two 0.2-mL benzene rinses of the pear-shaped flask were also added to the sample vials. A final volume reduction to 100 pL was accomplished by directing a slow stream of high-purity nitrogen gas onto the surface of the extract in the sample vial. One milliliter "Mini-Vials" (Alltech Associates, Inc., Arlington Heights, Ill.) were used for storing samples and were equipped with screw-caps fitted with Teflonfaced liners. In addition to five fly ash samples, 200 mL of benzene, in a Soxhlet apparatus containing an empty extraction thimble, was carried through the extraction and concentration steps and used as a procedure blank. All glassware, sample vials, and Pasteur pipets used in the extraction and concentration procedures were cleaned with the following procedure: ultrasonic agitation for 30 min in a 2% (approximate) aqueous solution of Alconox detergent (Alconox, Inc., New York, N.Y.), rinsed with copious amounts of hot tap water, rinsed thoroughly with deionized water, and heated in a general laboratory oven for 1h at 350 "C. All sample transfers were performed using Pasteur pipets and every Pasteur pipet was rinsed three times with 2-mL portions of benzene just prior to use. Gas Chromatographic Analysis. A Hewlett-Packard 5830A digital gas chromatograph (GC) with flame ionization detectors was equipped with a 2.6-m long, 2-mm i.d. glass column packed with a high performance material referred to here as Aue packing (22). This material is an ultra-thin, thermally treated layer of Carbowax 20M deposited as an 0.2% w/w layer on exhaustively acid-washed 100/ 120 mesh Chromosorb W. Chromatographic conditions were: initial temperature, 70 "C; program rate, 4 OC/min; final temperature, 250 "C; time at final temperature, 15 min; injection port temperature, 250 "C; detector temperature, 300 "C; helium carrier gas flow, 48 mL/min measured a t 70 "C oven temperature; attenuation, 32 or 64; slope sensitivity, 0.1 mV/min; and area reject, 1000. A normal hydrocarbon standard was run first, last, and between every two sample runs for use in the calculation of Kovats' retention indices under temperature programmed conditions. Gas Chromatography/Mass Spectrometry Analysis. A Hewlett-Packard 5992A Gas Chromatograph/Mass Spectrometer (GC/MS), equipped with a single floppy disk and an X-Y plotter, was used for regular GC/MS analysis and for selected ion monitoring (SIM) analysis. Prior to GC/MS analysis and following GC analysis the glass-packed column was transferred from GC to GC/MS and identical chromatographic conditions were established. Mass spectrometric performance was optimized daily using manufacturer supplied software. In the Peakfinder mode, mass spectra were continuously scanned a t a rate of 330 atomic mass units/s from m / e 500 to m / e 40. Spectra saved and stored on the flexible disk were those taken at the GC peak maxima. The spectrum of lowest abundance between consecutively saved spectra was also saved as background and at the conclusion of a Peakfinder run, each background spectrum was subtracted from its corresponding component spectrum. The software used in the Peakfinder runs was supplied by the manufacturer and modified by Dickson (13). This software allowed mass chromatograms and total ion current, in addition to individual mass spectra, to be stored on flexible disk. Operation of the mass spectrometer in the SIM mode achieves high sensitivity and selectivity for the detection of trace levels of organic compounds of interest in complex environmental mixtures. Six ions were monitored during each SIM run for the detection of compounds belonging to particular compound classes. These classes included: polycyclic aromatic hydrocarbons, poly-
______ Table I. Characteristic Ions Monitored during Selected Ion Monitoring Analysis of Extracts of Municipal Incinerator Fly Ash substance or compound class
ion ( d e )
set one 1. biphenyl 2. acenaphthene 3. fluorene 4. anthracene 5. fluoranthene 6. pyrene 7. benzanthracene 8. triphenylene 9. benzopyrene 10. benzofluoranthene 11. perylene set two 12. trichlorodibenzo-p-dioxins 13. tetrachlorodibenzo-p-dioxins 14. pentachlorodibenzo-p-dioxins 15. hexachlorodibenzo-p-dioxins 16. heptachlorodibenzo-p-dioxins 17. octachlorodibenzo-p-dioxins
set three 18. trichlorodibenzofurans 19. te trachlorodibenzofurans 20. pentachlorodibenzofurans 21. hexachlorodibenzofurans 22. heptachlorodibenzofurans 23. octachlorodibenzofurans set four 24. dichlorobiphenyls 25. trichlorobiphenyls 26. tetrachlorobiphenyls 27. pentachlorobiphenyls 28. hexachlorobiphenyls 29. heptachlorobiphenyls
154.1 154.1 166.1 178.1 202.1 202.1 228.1 228.1 252.1 252.1 252.1 285.9 321.9 355.9 389.8 425.8 459.7 269.9 305.9 339.9 373.8 409.8 443.7 222.0 256.0 291.9 325.9 361.8 393.8
chlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls. The various ions monitored are listed in Table I. The procedure blank was included in each set of GC/MS and SIM analyses. Retention indices were calculated using the computer program RICALC. Bar-graph plots were obtained by Calcomp plotter with the computer program GCPLOT (14). Both programs were written in the Fortran IV language to run under the WATFIV compiler on the University of Waterloo IBM 360/75 computer. Other work on fly-ash samples using this same analytical procedure shows a reproducibility of 25% relative standard deviation for GC peak heights between replicate samples taken from different parts of the fly-ash batch. Reproducibility of retention times between replicate samples is better than 5% relative standard deviation.
RESULTS A N D DISCUSSION G a s C h r o m a t o g r a p h i c Analysis. Figure 1 shows three gas chromatograms from the final concentrate of benzene extracts of (A) fly ash from The Netherlands, (B) fly ash from Japan 2, and (C) the procedure blank. Little significant contamination from the solvent, glassware, and sample handling is apparent from the chromatogram of the procedure blank. Two sizable peaks elute a t retention times of 27.85 and 39.41 min during the analysis of the procedure blank but were not present in a column blank run. These peaks were identified by GC/MS as phthalate esters and their concentrations estimated as 0.1 to 1 ng/pL of concentrated extract. Other compounds detected in the blank were present at concentrations too low to permit identification by GC/MS. The large number of trace organic compounds in municipal incinerator fly ash is illustrated in the chromatograms seen in Figure 1. In the Japan 2 sample (Figure lB), approximately 80 components were detected and these compounds had a wide volatility range, with boiling points for most components ranging from 150 t o 400 "C. The characteristic base-line rise observed
ANALYTICAL CHEMISTRY, VOL. 51, NO. 14, DECEMBER 1979
7-1
C
114
II I
~ R R E R 22087~
11
2-
12
, ----IA-__'-ds'-*cLI I
0
io
TIME'(minu*eS)610
Figure 1. Gas chromatograms of benzene extracts of (A) The Netherlands fly ash, (B) Japan 2 fly ash, and (C) the procedure blank.
Chromatographic conditions are given in the Experimental section during elution of The Netherlands sample (Figure 1A) was not observed in any of the other samples analyzed and is attributed to unresolved alkenes and branched hydrocarbons. The chromatograms of Figure 1 also illustrate the performance possible with Aue packing for the analysis of complex organic mixtures. Chromatograms of the five incinerator samples analyzed are compared in Figure 2 , which is produced by the computer program GCPLOT and is a plot of retention index vs. percent of total chromatographic area from the GC integration of the detector output. Total chromatographic area and sample identification is given a t the top of each plot. From previous studies, average flame ionization detector response factors for organic compounds commonly found in environmental samples were found to range from 200 to 600 area counts/ng, using the same equipment described here. Using an average response factor of 400 area counts/ng and the total chromatographic areas given in Figure 2 , the approximate amounts of organic materials detected per gram of fly ash were found to be; Japan 1, 0.4 pg/g; Japan 2, 1 pg/g; Ontario 1, 5 Fg/g; Ontario 2 , 30 pg/g; and The Netherlands, 20 pg/g. These values are considered as semiquantitative, since benzene extraction efficiencies with the Soxhlet apparatus have not been studied for organic compounds in fly ash. Also, errors during the final stages of sample preparation can be significant when concentrating samples to a final volume of only 100 pL. When using microliter syringes, the injection errors add 5 to 107~ to the total uncertainty in quantitation. Figure 2 shows significant differences in the mass distribution of eluting components extracted from the different samples. Most of the mass distribution of components in both Japan samples is spread evenly between retention index values 1100 to 2400. This contrasts sharply with the Ontario samples
1'4
16
18
20
2345
22
211
1
-
26 28 30 32 311 PSTEN1 ION INDWIM)
36
38
110
Figure 2. GCPLOT from gas chromatograms of fly ash samples from Japan, Ontario, and The Netherlands
in which the largest percentage of organic mass is from components which elute before hexadecane and also with the unique pattern of T h e Netherlands sample. Note that the GCPLOT bar-graph representations of the Japan 2 and Netherlands samples are very comparable to the raw chromatograms of these samples (Figure 1). GC/MS Analysis. A list of compounds identified by GC/MS from the five fly-ash samples is given in Table 11. Peak abundances, which are also given, were obtained by summing all ion abundances in the mass spectrum taken a t the top of each detected, eluting peak. Although not very useful for exact quantitation, these abundances give a good indication of relative concentrations among the samples. Where possible, retention times of identified components were matched with those of available standards. These compounds are indicated in Table 11. Since the chromatographic packing employed possesses a very thin liquid stationary phase, retention times of compounds have been observed to vary greatly between different batches. For a given column, retention times under identical chromatographic conditions are normally reproducible to better than 5 % relative standard deviation. Calculated retention indices for hydrocarbon standards ranging from tetradecane to dotricontane (CI4to CS2)t h a t were treated as unknowns in a previous study had average standard deviations of 2 retention index units ( 1 1 ) . Retention indices listed in Table I1 were calculated from the retention times of naturally present n-alkanes. Approximately 100 individual compounds in the five samples were identified by GC/MS and, while some components were present in more than one sample, very few were detected in all five samples. The Netherlands and Ontario samples contained fewer and less of the polychlorinated benzenes than the Japan samples, although hexachlorobenzene was very abundant in the Ontario 1 sample. I n the Japan 1, Japan 2, and Ontario 1 samples, the pentachloro- and hexachlorobenzenes were among the most abundant of any of the detected compounds. In contrast, the Netherlands sample contained large numbers of olefinic and branched aliphatic hydrocarbons, many of' which were
2346
ANALYTICAL CHEMISTRY, VOL. 51, NO. 14, DECEMBER 1979
Table 11. Comparison of Total Mass Spectral Peak Abundances from GC/MS/CAL Analyses of Extracts of Municipal Incinerator Fly Ash no. 1.
2. 3.
4. 5. 6. 7. 8. 9. 10. 11.
12. 13. 14. 15.
16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37.
38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57.
compoundU naphthalene tridecane tetrachlorobenzene tetrachlorobenzene unsatlbranch hydrocarbon methylnaphthalene methylnaphthalene tetradecane' tetrachlorobenzene chloronaphthalene biphenyl? , pentadecaner pentachlorobenzene unsatlbranch hydrocarbon unsatjbranch hydrocarbon unsatlbranch hydrocarbon acenaph th ylene hexadecane t C,,H,, C,H,CI,O or C,H,C1,0, dibenzofuran hexachlorobenzene unsatlbranch, hydrocarbon hep tadecaneT chlorobiphenyl CI >HI2 0 4 trichlorophenol unsatlbranch hydrocarbon unsatlbranch hydrocarbon tetrachlorobenzofuran tetrachlorobenzofuran unsatlbranch hydrocarbon tetrachlorobenzofuran tetrachlorophenol nonadecanet pentachlorophenol C,,H,,: anthracene phenanthrene diphenylace tylene eicosanet C, ,H,O: fluorenone tetrachlorobiphenylene pentachloronaphthalene unidentified phthalate heneicosanet unsatlbranch hydrocarbon pen tachloronaphthalene dibenzoheptafulvene dibutylphthalate' docosanet unsatlbranch hydrocarbon benzil pentachloronaphthalene unsatlbranch hydrocarbon anthraquinone hexachloronaphthalene fluoranthenet xanthone unidentified M' = 204.1
58.
tetrachlorodibenzodioxin
59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69.
pyrene te trachlorodibenzofuran tetrachlorodi benzodioxin tetracosanet pentachlorodibenzofuran p-chlorobenzoyl chloride chloroacetophenone tetrachlorodibenzodioxin
pentacosanet pentachlorodi benzofuran pentachlorodi benzofuran
retention retention time, min index 3.9 4.3 5.1 5.3 5.9 5.9 6.3 6.6 7.2 8.4 8.5 9.0 9.2 10.2 10.5 11.1 11.4 11.6 11.7 12.3 13.1 13.2 13.9 14.2 14.3 15.4 15.8 15.9 16.3 16.5 17.3 17.4 18.1 18.6 19.4 19.9 21 .o
1283 1300 1337 1345 1370 1370 1387 1400 1424 1474 1479 1500 1507 1546 1558 1573 1592 1600 1604 1627 1657 1661 1688 1700 1703 1746 1761 1766 1781 1788 1819 1823 1850 1869 1900 1927 1988
21.2 21.5 22.2 23.3 23.9 24.1 24.6 25.0 25.5 26.1 26.3 26.5 26.6 27.3 27.5 27.6 27.9 28.4 28.6 29.1 29.3 29.5 29.9 30.0 30.6 31.4 31.8 31.8 31.9 32.6 32.9 33.0
2000 2010 2034 2072 2093 2100 2123 2140 21 64 2190 2200 2209 2213 2246 2256 2260 2274 2297 2306 2330 2340 2348 2367 2372 2400 2440 2459 2459 2465 2500 2517 2522
total mass spectral peak abundances 01
__ 827 744 567
---__
1314
--
__
-5044
__
--_1444
--
1028
__ -720 -_ ----
11186
_ -
778 728
--
1077 714 759 745 1129
_-
2151
_-
1815
_-
1827
_-
1815
--
1897 1747
__ _1173 --1035
----
755
--
689
--
1187 305
---
641 1225 991 713
ANALYTICAL CHEMISTRY, VOL. 51, NO. 14, DECEMBER 1979
2347
Table I1 (Continued) no.
compounda
70.
pentachlorodibenzofuran dicyclohexyladipate
71. 72. 73. 74. 7 5. 7 6. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87.
pentachlorodibenzodioxin
he xacosane t pentachlorodibenzodioxin
benzilbu tylphthalate unidentified phthalate hexachlorodi benzofuran hep tacosane? pentachlorodibenzofuran dioctylphthalate hexachlorodibenzodioxin hexachlorodi benzodioxin hexachlorodibenzodioxin hexachlorodibenzodioxin unidentified phthalate hexachlorodibenzodioxin hexachlorodibenzodioxin heptachlorodibenzofuran
88.
89. 90. 91. 92. 93. 94. 95. 96. 97. 98.
heptachlorodibenzodioxin
unsatlbranch hydrocarbon heptachlorodi benzodioxin unsatlbranch hydrocarbon benzofluoranthene unidentified phthalate octachlorodibenzofuran, benzopyrenes, perylene' octachlorodi benzodioxin triphenylene, diphenylbiphenyl triacontanet
99. a
retention retention time, min index 33.6 33.8 34.3 34.4 34.7 34.9 35.6 35.8 36.3 36.8 37.6 37.6 37.8 38.2 38.9 39.6 39.6 40.0 40.0 41.3 41.4 42.3 43.1 43.6 44.4 44.8 45.1 45.1 45.4
2556 2567 2594 260G 261 6 2626 2663 2674 2700 2715 2739 2739 2746 2758 2780 2801 2801 2813 2813 2853 2856 2884 2908 2923 2948 2960 2969 2969 2978
46.1
3000
__
total mass spectral peak abundances 01
1981
_-
1494
_-
683
__-
1415
--
1107
2369 trace
_-
1874 661
__
4391
--
__
823
883 967* 967* 1247
4435
985
1524
--
-_
--
2555
* Indicates incomplete resolution making quantitation uncertain.
__
__ -_ __ --_ __ -_ -_
Indicates retention time match with stcndard solu-
tion.
-___ ?l/E
=
305 9
339 9
373 E
I
qL13
7
E'
TIME I N M I N U T E 5 3 Figure 3. Plots of SIM data from analysis for PCDFs in fly ash samples. Ions monitored are given above each class and represent the tetra4305.9), penta-(339.9), hexa-(373.8), hepta-(409.8), and octachlorodibenzofuran (443.7). Full scale abundances are in the upper right corner
not specifically identified and therefore not included in Table 11. Polycyclic aromatic hydrocarbons predominated in Ontario
2, which was the only sample t o contain significant amounts of benzo[a]pyrene. A series of normal hydrocarbons were
2348
ANALYTICAL CHEMISTRY, VOL. 51, NO. 14, DECEMBER 1979
M/E =
321 9
35.5 9
L125 . E
389 B
r I
li
+
759 7
69
IL L 6
+ f
I33
li,
L
L
A,-
+
iN
AI
I
*
+
j
I30
B '38.1 '*.I' 9B '99 B
TIME I N MINUTE5
+
Figure 4. Plots of SIM data from analysis for PCDDs in fly ash samples. Ions monitored are given above each class and represent the tetra-(321.9), penta-(355.9), hexa-(389.8), hepta-(425.Q and octachlorodibenzodioxin (459.7)
-
M/E Figure 5. Mass spectra of isomers of (A) octachlorodibenzodioxin, (B) heptachlorodibenzodioxin, (C) hexachlorodibenzodioxin, (D) pentachlorodibenzodioxin, and (E) tetrachlorodibenzodioxin. Spectra were from GC/MS analysis of fly ash from 0 2 .
detected in every sample and the range of carbon chain lengths varied from CI3Hz8to C34H66.Levels of these hydrocarbons generally were low relative to other components in the fly-ash
extracts. The data for normal hydrocarbons were obtained from mass chromatograms generated in real-time by the data acquisition software (13).
ANALYTICAL CHEMISTRY, VOL. 51, NO. 14, DECEMBER 1979
[ F.S.
Table 111. Estimated Concentrations' (ng/g) of TCDDs in Fly Ash 01
02
N
29.6
2
1
30.1 31.1
2
0.9
0.3 0.3
3
2
0.6
1 0.3
1 3 1
1 4 0.4
0.3
0.2
0.6
0.3 0
33.0
lOOWO0
1
Sample
retention time, min
31.6 32.2
2349
0.3
J1
52
3
5 2
0.5 0.5 0.5 0
7550-
25 -
a Concentrations based o n 1,2,3,4-TCDDstandard solution. Relative response factors are assumed to be one.
Selected Ion Monitoring (SIM). The procedure blank was free of detectable levels of polychlorinated dibenzofurans, polychlorinated dibenzo-p-dioxins, PCBs and PAHs. Figures 3 and 4 summarize the SIM data obtained for the tetrachlorothrough octachlorodibenzofuran isomers and the tetrachlorothough octachlorodibenzo-p-dioxin isomers, respectively. Retention times of isomers of the various chlorinated compounds were known from mass spectral data obtained with the G C / M S runs described earlier (Table 11). The remarkable feature of Figure 3 is that both the number and the relative concentrations of various chlorinated dibenzofurans are very similar in all five samples. The Japanese samples both show greater amounts relative to other PCDFs of the tetrachlorodibenzofuran isomers but the Netherlands and Ontario samples contain greater relative amounts of the pentachlorcdibenzofuran and hexachlorodibenzofuran isomers. Octachlorodibenzofuran was present at very low but detectable levels in all samples except Ontario 2. Figure 4 shows additional quantitative and qualitative differences among the samples. T h e isomers of the PCDDs in both samples of Japanese origin are almost qualitatively identical, but the 52 sample contains about twice the concentration of each PCDD isomer. The PCDD isomers in the Ontario samples are also nearly identical to each other qualitatively, but the 0 2 sample has twice the detected amounts of PCDDs. The Netherlands sample is qualitatively closer to the Ontario samples; however, only traces of TCDD isomers were detected. Much larger levels of the heptachloro- and octachlorodibenzo-p-dioxinisomers were detected in the Netherlands sample than in any of the other four samples. Retention times for the various PCDD isomers were determined and some PCDD isomers were present in large enough quantities to allow mass spectra to be collected. Figure 5, A-E shows mass spectra for the octachloro- to tetrachlorodibenzop-dioxin isomers, respectively. The mass spectra were obtained for each series from the 01 sample. Additional confirmation for the TCDD isomers was obtained by running the 1,2,3,4-and 2,3,7,8-TCDD isomers under the same conditions. The isomers a t retention times 31.5 and 32.5 matched retention times of the 1,2,3,4- and 2,3,7,8-TCDD isomers, respectively. The TCDD isomers were separated into six partially resolved peaks. The peaks, which eluted a t 29.6, 30.1, 31.6, 32.2 and 33.0 min, were quantitated by comparison of peak heights to a known amount of 1,2,3,4-TCDD run under the same conditions. A relative response factor of one for all isomers relative to 1,2,3,4-TCDD was assumed and corrections for differences in injection volumes and fly-ash sample sizes were made. The final values given in Table 111, expressed as ng/g, indicate a range of 1 to 5 ng/g for individual peaks or a composite range of 2 to 10 ng/g of TCDDs in the fly-ash samples. T h e samples also differed in the presence and abundance of PAHs. Figure 6 shows a GCPLOT of PAHs in the five samples and a comparison of plots clearly illustrates that 0 2
111 25
RETENTICIN TlMEIHIN)
Figure 6. GCPLOT from SIM analysis of PAHs in fly ash samples from J1, J2, 01, 02, and N. Compounds and retention times (minutes) are: fluorene, 14.5; anthracene, 20.5; pyrene, 27.8; fluoranthene, 29.1; benzanthracene, 37.2; benzo[ k]fluoranthene, 43.2; and benzo[a]pyrene, 44.8
Table IV. Estimated Concentrationsa (ng/g) of PAHs in Fly Ash sample compound
01
OF
fluorene anthracene fluoranthene pyrene benzanthrene benzofluoranthene benzo[a] pyrene
0 10
10 500 500 500
2
1 0 0 0
300 400 400
N
J1
52
60
0
0
200 20
10 3 1
10 0
10 0 0 0
4 0 0
0 10 0 0
a Fluorene, anthracene, fluoranthene, and pyrene are based o n the response of a pyrene standard solution and an assumed relative response of one. Benzofluoranthene and benzo[a]pyrene values are based on the response of a benzo[a] pyrene standard solution and assumed relative response of one.
contains the greatest number of PAHs and these PAHs a t higher concentrations. The Netherlands sample contained appreciable amounts of anthracene while 01, J1, and 52 contained very little of any PAH. Table IV contains the estimated concentrations of PAHs. The samples were also analyzed by SIM for the presence of PCBs. PCBs were detected in 0 2 and N samples a t low levels (less than 1 ng/g of fly ash). Qualitative and quantitative isomer distributions of tetra-, penta-, and hexachlorobiphenyls in 0 2 and tetra- and pentachlorobiphenyls in N closply resemble those seen in Aroclor 1254. Other samples showed no detectable levels of PCBs. Although the distribution of trace organic compounds was quite different in the samples studied from the different countries, polychlorinated dibenzo-p-dioxins and poly-
2350
ANALYTICAL CHEMISTRY, VOL. 51, NO. 14, DECEMBER 1979
chlorinated dibenzofurans were present in every sample. This suggests that these compounds are formed universally during incineration processes although the combustible material and incineration conditions may vary.
LITERATURE CITED
(9) I. W. Davies, R. M. Harrison, R. Perry, D.Ratnayaka, and R. A. Wellings, Environ. Sci. Techno/., IO. 451 (1976). (,o) A. di Domenics, F. Merli, L. Boniforte, I. Camoni, A . Di Muccio, F. Toggi, L. Vergori, G. Colii, G. Elli, A. Gorni, P. Gtassi, G. Invernizzi, A. Jemma, L. Luciani, F. Cattabeni, L. De Angelis, G. Galli, C. Chiabrando, and R. Fanelii. A n d . Chem., 51, 735 (1979). F. W. Karasek, D. W. Denney, K. W. Chan, and R. E. Clement, Anal. Chem., 50, 82 (1978). W. A. Aue, C. R. Hastings, and S. Kapila, J . Chromatogr., 77, 299 (12) (1973). (13) L. C. Dickson, "Software Improvements for GC/MS/Caiculator Used In Trace Organic Analysis of Environmental Samples", Department of Chemistry Report, University of Waterloo, Waterloo, Ont., April 1979. (14) R. E. Clement, "Application of Computer Techniques to the Collection and Analysis of Analytical Data", M.Sc. Thesis, University of Waterloo, Waterloo, Ont., August, 1976.
F. N. Rubel, "Incineration of Solid Wastes, Pollution Technology Review No. 13, Noges Data Corp., Park Ridge, N.J., 1974, p 4. H. Freeman, Environ. Sci. Techno/., 12, 1252 (1978). D. A. Vaughan, P. D. Miller, and W. K. Boyd, in "Resource Recovery Through Incineration", The American Society of Mechanical Engineers, New York, 1974, p 187. K. Olk, P.L. Verrneulen, and 0. Hutzinger, chemosphere, 6, 455 (1977). H. R. Buser, A. Bosshardt, C. Rappe, and R. Lindehl, Chemosphere, 7, 417 . , . ,(1!27R\ . - . - ,. H. R. Buser, H. Bosshardt, and C. Rappe, Chemosphere, 7, 109 (1978). The Chlorinated Dioxin Task Force, Michigan Division Dow Chemical,
RECEIVED for review Julv 10. 1979. AcceD
R L. Rawls: Chem. Eng. News, 57 (7) 23 (1979).
of the Environment, Air Resources Branch
Elemental Analysis of Thick Obsidian Samples by Proton Induced X-ray Emission Spectrometry Peter Duerden," D. D. Cohen,' Eric Clayton, and J. R. Bird Australian Atomic Energy Commission Research Establishment, Private Mailbag, Sutherland, NS W 2232, Australia
W. R. Ambrose Depatfment of Prehistory, Research School of Pacific Studies, Australian National University, P.O. Box 4, Canberra, ACT 2600, Australia
B. F. Leach Department of Anthropology, University of Otago, Dunedin, New Zealand
Proton induced X-ray emission is shown to be sultable for the analysis of thick obsldian samples and artifacts with no special treatment other than washing prlor to mounting in a sample chamber vacuum system. X-ray spectra observed unfiltered and with plastic or pinhole filters are compared. Using a pinhole filter and a single measurement of approximately 4min duration followed by thick target yield calculations, a fiR to the observed spectra gives concentrations of such elements as K, Ca, Ti, V, Mn, Fe, Rb, Y, Sr, Zr, Nb, Ta, and Pb. Results for selected source samples from the Pacific region show that the technique provides a sultable method for distinguishing between many of the sources.
Many analytical techniques have been used t o study the composition of obsidian from different source regions. In 1976, Nielsen e t al. ( I ) reported the use of Proton Induced X-ray Emission (PIXE) for such measurements. However, they used samples that were specially prepared from acid digests of 30 to 100 pg of finely powdered obsidian, a portion of which was evaporated to dryness on Nucleopore membrane filters. Because of the importance of rapid, nondestructive techniques for the study of artifact collections, we have investigated the use of P I X E measurements on thick samples with no treatment other than washing. Present address, Australian Institute of Nuclear Science and Engineering, Private M a i l Bag, Sutherland, N.S.W. 2232, Australia. 0003-2700/79/0351-2350$01.00/0
Proton induced y rays have been shown to be suitable for nondestructive analysis of obsidian artifacts ( 2 ) ,b u t when measuring X-ray yields, the greater effects of absorption in the sample and variations in surface condition raise doubts about their suitability for elemental analysis. P I X E studies of thick samples have shown that, for samples which are closely related in composition, accurate determination of many elements is possible (3)and this experience has been used for developing methods for the study of obsidian. The classification of obsidian artifacts by their chemical similarity to known sources has been used extensively in the study of trade and migration in regions such as the Mediterranean, the Americas, Japan, and Oceania ( 4 ) . We are participants in an investigation of obsidian from the latter region, with particular interest being centered on the South West Pacific and source samples are available to us from all known flows in this region. The majority of samples studied to date are from the Admiralty Group, New Britain, the d'Entrecasteaux Islands, the New Hebrides, and New Zealand. In addition, samples are available from Easter Island, Hawaii, Indonesia, Australia, and other locations. Previous work on the characteristics and geographic distributions of volcanic glasses in Oceania has been reviewed by Smith, Ward, and Ambrose ( 5 )* Data from about 40 source samples are used in this report. Although not included, measurements have also been made on a considerable number of artifacts to confirm that the methods give satisfactory results for samples of various ages which have been subjected to a variety of treatments prior to collection for study. An additional parameter of importance 1979 American Chemical Society
