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
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
no. causing cell transformation
7 (6%) 7 (10%) 5 (4%) 19 (6%)
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
(0.016, 0.102) (0.002, 0.116) (0.028, 0.171) (0.005, 0.195) (0.006, 0.081) (0.006, 0.093)
@ 1981 American Chemical Society
finished water total = 0.06
transformatlon obsd
no transformation obsd
raw total
7
12
111 110 22 1
118 115 223
7 7 14
111 63 174
118 188
5
110 63 173
115 70 185
5
x2
B. river water raw water total = 0.54
70
x2
C. finished water raw water total = 1.45
7
12
x2
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121
statistical significance to their findings. However, simply using the total number of samples in each of the river, raw, and finished categories, we have calculated the 95 and 99% confidence intervals for the probability of a transformation in each of the water types by applying binomial distribution theory. One would assume that the probability of a transformation in the control group is very small. If this probability is less than the lower limits of the intervals shown in Table 11, the particular water category can be said to have had cellular transformations at a statistically significant level (0.0275 and 0.005 levels for the 95 and 99% intervals, respectively) compared to the corresponding control group. Let us now compare results between groups. Two-way contingency tables comparing the observed results for the three classes of tested waters are shown in Table 111.The x2 statistic indicates that there is no significant difference between the number of cell transformations found using river, raw, or finished samples. Conclusion: neither conveyance of river water to treatment plants nor treatment itself reduces whatever unknown mechanisms cause the indicated transformations.
SIR: We appreciate the questions and statistical efforts of Kaplan and Thode with respect to our paper. An estimate of the expected number of transformations in the controls is given in the table taken from our paper by Kaplan and Thode. Fifty control cultures were serially propagated for 8 weeks with no cell transformation seen among the progeny. In addition, other studies with this cell line were carried out over a 2 yr period. If one assumes, as they have done, that a binomial distribution is appropriate, then the estimate of the variance and the confidence interval that does not overlap zero is significant; therefore, the intervals calculated by Kaplan and Thode in their Table I1 indicate that all types of water samples tested were significantly different from the controls at 95 and 99% confidence limits except finished water at the 99% level. Results between treatment groups as compared by Kaplan and Thode indicate no significant differences. The only proper comparison is between controls and any one of the three
The reported results would have been far more important if we had had additional information as to control samples. Furthermore, the authors allude to organic compounds as causing the transformations, substances we presume are present at very low concentrations whose detection requires sophisticated technology. ,It thus behooves the authors to provide further information as to the characteristics of the sampling sites (e.g., below sewage outfalls, downstream of industrial point sources of discharges, etc.), as well as the times of sampling (e.g., before or after chemical spills, hydrological conditions, etc.). Despite these shortcomings, the studies by Pelon and associates are important to our understanding of relationships between human health and water contaminants of a class significantly different from those we have faced in generations past. Edward Kaplan Henry C. Thode, Jr. Brookhaven National Laboratory Upton, New York 11973
treatments. The cell transformations may have been caused by the same or different chemicals. Our research did not attempt to determine precise causes of transformations since all three water types contain numerous organic and inorganic compounds. We made no statement that the cell transformations were caused by organic compounds, but we did state that organic compounds were present. Detailed information regarding point sources of industrial discharges of organic and inorganic .compounds within the sampling area may be obtained from the initial citation in our paper.
William Pelon David E. Lesley Department of Microbiology and Immunology Louisiana State University Medical Center 1100 Florida Avenue New Orleans, Louisiana 701 19
Correction
1980, Volume 14 Mendel Friedman,* M a r t i n J. Diamond, a n d J a m e s T. MacGregor: Mutagenicity of Textile Dyes. Page 1145. In Table I, compound 4 should be (2.1. Reactive 83.
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