Table II. Summary of the Example Calculation d
P
3.1396 X 5.7713 X 10 x 10-6 17.3279 X lov6 31.8524 X
0.9339 0.7938 0.4999 0.1247 0.0008
U
V
-2.02018 -0.95857 0 0.95857 2.02018
- 12.6714 - 12.0626
- 11.5129 -10.9631 -10.3543
P
calculation sequence is simple. With the specified values of d o and d, calculate 6, and si. With the roots from Table I, calculate the five required values of u by using eq 3. Calculate the corresponding values of d by exponentiating u. Determine p for each of these values of d . Use eq 6 to calculate the required five values of f . Then using the weighting factors and eq 5, determine the value of the integral. Calculate the overall mass penetration by using eq 4.
d d,
= = =
d,
=
f
=
n p
=
Example
u
For a specific set of operating and design perameters, the size penetration of a precleaner has been determined to be
u
p = e-6.9314X109d2
u
w
(7)
d o and d, have been determined experimentally and are remeters. ‘iland gU are then and 10 X spectively 15 X calculated as previously described and are -11.5129 and 0.4055. The remainder of the calculations are summarized in Table 11.
f
0.028 90 0.15259 0.499 98 0.649 16 0.028 52
uu
= = =
= = =
W
0.01995 0.393 61 0.945 30 0.393 61 0.01995
wf
0.000 57 0.060 06 0.472 64 0.255 52 0.000 56 = 0.78937 P = 0.21249
overall mass penetration, fraction particle diameter, meters particle diameter for which the cumulative distribution is 0.5, meters particle diameter for which the cumulative distribution is 0.841, meters function defined by eq 6 number of particles between sizes u and u + du penetration as a function of size, fraction natural logarithm of d natural logarithm of d, transformation defined by eq 3 weightingfactor natural logarithm of d,/d,
Literature Cited
Nomenclature
(1) Crawford, M. “Air Pollution Control Theory”; McGraw-Hill: New York, 1976; Chapter 4. (2) Carnahan, B.; Luther, H. A.; Wilkes, J. 0. “Applied Numerical Methods”; Wiley: New York, 1969;Chapter 2. (3) “Handbook of Mathematical Functions”; Natl. Bur Stand ( U S ), Appl. Math Ser. 1964,55, Chapter 25.
N
Received for review March 3,1980. Accepted September 30, 1980
=
number of particles
CORRESPONDENCE
SIR: Van Vaeck, Broddin, and van Cauwenberghe (1, 2) reported n-alkanes ranging from CISto C32 with a strong odd carbon number predominance and n-carboxylic acids ranging from C14 to Czs with a strong even carbon number predominance in suburban, rural, and seashore aerosols. It is the interpretation of these data with which I am in disagreement. I quote: The alternation of the aliphatic hydrocarbons is explained tentatively by assuming selective volatilization of the even n-alkanes compared to the uneven ones (1). This phenomenon could be caused by a volatilization artefact on the filter, since there seems to be a correlation with the alternating behavior of the molar heat of vaporization of the alkanes. Indeed, the increment of the molar heat of vaporization per carbon atom from an even to an uneven homologue is higher than from an uneven to an even. The volatilization of the even homologues can thus be expected to occur to a somewhat greater extent than that of the uneven paraffins under nonequilibrium conditions (2). However, it seems that desorption of the even aliphatic hydrocarbons could occur not only from collect120
Environmental Science & Technology
ed material during sampling but also during transport of the aerosol in the atmosphere. Furthermore, during the formation process of the aerosol, the uneven homologues could also adsorb preferentially to the particles from the gas phase ( 1 ) . Based on our data (3-6) and that of other authors (e.g., ref 7), I suggest that these n-alkanes and n-fatty acids in the range of C ~ S - C ~simply ~ + represent the vascular plant waxes. The morphology of epicuticular wax of most higher plants can be easily damaged by wind abrasion, sloughing, and other processes, thus directly generating particulate matter (4-6, 8, 9). The organic constitution of plant waxes has been extensively analyzed; they consist primarily of n-alkanes, n -fatty alcohols, n-fatty acids, ketones, all greater than -CZZ, and minor amounts of some anteiso analogues, and aldehydes (10). These same compositions and distributions of homologues are found in aerosols from remote areas where the anthropogenic influence is minimal (3-6, 11 ). Additional molecular markers derived from resinous plants have also been identified in rural aerosols (6).These are comprised of sesqui- and diterpenoids, and the major analogues are dehydroabietic acid (I), dehydroabietane (11),and dehydroabietin (111).The hydrocarbons larger than C23 have also been confirmed to be of a vascular plant origin by stable carbon isotope analysis (6).
0013-936X/81/0915-0120$01.00/0
@ 1981 American Chemical Society
Literature Cited (1) Van Vaeck, L., Broddin, G., van Cauwenberghe, K., Entriron. Sci. Technol., 13,1494-1502 (1979). (2) . , Van Vaeck. L.. Broddin. G.. Cautreels.. W.., van Cauwenberehe. K., Sci. Tot. Enuiron., 11,’41-52 (1979). (3) Simoneit, B. R. T., Chester. R., Eelinton, G., Nature (London). 267,682-5 (1977). (4) Simoneit, B. R. T., Mar. Chem., 5,443-64 (1977). ( 5 ) Simoneit, B. R. T., in “Carbonaceous Particles in the Atmosphere”, Novakov, T., Ed., NSF-LBL, LBL-9037, 1979, pp 23344. (6) Simoneit, B. R. T., in “Advances in Organic Geochemistry 1979”,
-
I
I I1 dehydroabietic acid dehydroabietane
I11 dehydroabietin
Aerosols from urban areas (e.g., Los Angeles) also exhibit this higher plant wax component among the residues from fossil fuels (11-13); however, sometimes it can be almost completely overwhelmed by the nonwax bitumen (11).Thus, both the n-alkanes (>C23) and the n-fatty acids (>C22) in the aerosols analyzed by van Vaeck et al. ( I , 2 ) are most likely primary particulates also derived from higher plants. The proposed volatilization or condensation which is carbon number predominance specific ( I , 2 ) has no precedent in the distillation or evaporation of petroleum, where the no-carbon predominance is preserved. This odd carbon predominance of the n-alkanes does not appear to be a high-volume filtration artefact ( I , 2). We have sampled aerosols by the mesh (single fiber nets) method (3-5) and by high-volume filtration (5,6, 11, 12), and the results were the same. The mesh collects predominantly the larger particulates (50% < 2 pm, 70% < 4 pm) (3).This indicates that vascular plant wax is in part a particulate component of aerosols. Furthermore, the term “pollutant” is inappropriate for the hydrocarbons and fatty acids derived from natural biogenic sources (1, 2 ) . These natural products were a Component of the atmosphere long before the advent of man’s pollution. Even fossil fuel residues in the environment are not true pollutants, but they may be better termed contaminants (12, 14).
SIR: Research on the impacts of water quality on cellular functions accounts for increasing amounts of interest, time, and funds. The paper “Transformation of the Mouse Clonal Cell Line R846-DP8 by Mississippi River, Raw, and Finished Water Samples from Southeastern Louisiana” (Enuiron. Sei. Technol., 14,723 (1980)], by Pedon et al., represents one of a number of similar projects focusing upon this very timely and important area. The authors cultured a particular mouse cell line by using Mississippi River water, as well as water from the same source as it entered and left treatment plants (samples termed “raw” and “finished”, respectively). Samples were‘ obtained from several sites, a t various times, with results shown in Table I (taken directly from Pelon). Several interesting observations follow directly. First, since no estimate is given of the expected number of cell transformations using controls, the authors cannot assign levels of
Douglas, A. G., Maxwell, J. R., Eds., Pergamon Press, Oxford, in press. (7) Arpino, P., van Dorsselaer, A., Sevier, K. D., Ourisson, G., C. R. Acad. Sci., Ser. D, 275,2837-40 (1972). (8) Martin, J. P., Juniper, B. E., “The Cuticles of Plants”, St. Martins Press, New York, 1970. (9) Smith, W. H., Staskawicz, B. J., Enuiron. Manage., 1, 317-30 (1977). (101 Kolattukudy, P. E., Ed., “Chemistry and Biochemistry of Natural Waxes”, Elsevier, Amsterdam, 1974. (11) Simoneit, B. R. T., Mazurek, M. A., Cahill, T. A., J. Air Pollut. Contr. Assoc., 30,387-90 (1980). (12) Simoneit, B. R. T., Mazurek, M. A., manuscript in prepara-
tion.
(13) Eichmann, R., Neuling, P., Ketseridis, G., Hahn, J., Jaenicke, R., Junge, C., Atmos. Environ., 13,587-99 (1979). (14) This is Contribution No. 1999 from the Institute of Geophysics
and Planetary Physics, University of California at Los Angeles. I thank the Atmospheric Resiarch Section, National Science Foundation (Grant ATM 79-08645), and the Electric Power Research Institute (Contract TPS 79-732) for financial support.
Bernd R. T. Simoneit Institute of Geophysics and Planetary Physics University of California Los Angeles, Calif. 90024
Table 11. Confidence Intervals for the Probability of Cellular Transformation water category
no. of transformatlons/no. 95 % confidence 99 % confidence of samples interval Interval
river water raw water finished water
7/118 = 0.059 7/70 = 0.100 5/115 = 0.043
Table 111. Contingency Table Comparisons of Pairs of Water Categories
A. river water
finished water total = 0.06
Table 1. Transformation of R846-DP8 Cells by Water Samples Collected in Southeastern Louisiana (Aug 1974-May 1976)” water sample type
river raw finished total
no. of tested
118 70 115 303
A total of 50 negative control cultures, each propagated over 8 weeks, showed no evidence of cell transformation. E
0013-936X/81/09 15-0 12 1$01.OO/O
transformatlon obsd
no transformation obsd
raw total
7
5 12
111 110 22 1
118 115 223
7 7 14
111 63 174
118
5
110 63 173
115 70 185
x2
B. river water raw water total = 0.54
no. causing cell transformation
7 (6%) 7 (10%) 5 (4%) 19 (6%)
(0.016, 0.102) (0.002, 0.116) (0.028, 0.171) (0.005, 0.195) (0.006, 0.081) (0.006, 0.093)
70
188
x2
C. finished water raw water total = 1.45
@ 1981 American Chemical Society
7
12
x2
Volume 15, Number 1, January 1981
121
