Table II. Dose-Dependent Mutagenicity of Two Compounds Found in the Buffalo River concn, Ccg/mL
4-(dimethylamino)benzophenone
4-(dimethylamino)benzaldehyde
background benzo [ a] pyrene
25 50 75 100 100 300 1000 20
105
x
IMF
*
18 22
41 49 31 40 79 13f 1 200 f 50
induced mutant fraction: see ref 6 for details. All compounds were assayed in the presence of Aroclor-induced postmitochondriai supernatant. a
IMF =
turing plant used the Buffalo river bank as a dump for experimental or failed dye production batches. Leaching and runoff from this dump have transferred many of the dye-related chemicals into the Buffalo River and its sediment. In the river, fish have been exposed to these compounds by direct contact with contaminated sediment. Since some of these compounds could be mutagenic or carcinogenic, it is not unreasonable to assume that the chemicals originally derived from the dyestuff manufacturer’s dump are at least partially responsible for the tumors observed in fish taken from this river. Acknowledgment We thank W. Zapisek (Canisius College) for providing the soil samples and J. Spagnoli (New York State Department of Environmental Conservation) for help in obtaining the sediment samples. We also thank W. G. Thilly and B. M. Andon for the bioassay experiments. Literature Cited
are present in substantial amounts in the sediment (see Table I) and that bothi have previously been detected in fish obtained from the Buffalo River ( 4 ) . Compounds 3,4,5, and 8 were bioassayed to determine their individual mutagenic activity by using a quantitative forward bacterial mutagenesis assay described elsewhere (6, 7). Benzo[a]pyrene was run as a positive control in each mutation assay. Only compounds producing an induced mutant fraction at least twice background were considered to give a positive mutagenic test. Both 4-(dimethy1amino)benzophenone and 4-(dimethylamino)benzaldehydeinduced significant mutation to 8-azaquanine resistance in S. typhimurium (see Table 11). These two compounds have up to 5% of the activity of benzo[a]pyrene on a weight basis. The following scenario emerges from these chemical and biological data. Over several years, this dyestuff manufac-
(1) Kraybill, H. F. Prog. Exp. Tumor Res. 1976,20, 34. (2) Black, J. J.; Holmes, M.; Dymerski, P. P.; Zapisek, W. F. In
“Hydrocarbons and Halogenated Hydrocarbons in the Aquatic Environment”, Afghan, B. K., Mackay, D., Eds.; Plenum Press: New York, 1980; p 559. (3) Paigen, B.; Braun, M.; Steenland, K.; Holmes, E.; Cohen, H., Roswell Park Memorial Institute, Buffalo, NY, private communication, 1980. (4) Diachenko, G. W. Enuiron. Sci. Technol. 1979,23, 329. (5) “1974 Directory of Chemical Producers, United States”; Stanford Research Institute: Menlo Park, CA, 1974. (6) Skopek, T. R.; Liber, H. L.; Kaden, D. A.; Thilly, W. G. Proc. Natl. Acad. Sci. U.S.A. 1978. 75. 4465. (7) Krishnan, S.; Kaden,.D. A,;Thilly, W. G.; Hites, R. A. Enuiron. Sci. Technol. 1979, 23, 1532.
Received f o r review January 4, 2980. Accepted June 16 1980. This work has been supported by the U.S. Environmental Protection Agency (Grant No. 806350).
CORRESPONDENCE
SIR: The work of Rollins and Homolya ( 1 ) has been noted with great interest. The levels of chlorides that were found come as no surprise, as I had personally been involved in the early studies ol’ Carotti and Kaiser ( 2 ) . Rollins and Homolya have estimated ambient levels of HC1 aerosol and suggest a secondary transformation possibility in which some of the HC1 might be transformed into ammonium chloride. The presence of the latter species has been previously reported by Cunningham et al. ( 3 ) and Hindman et al. ( 4 ) . Each of these studies found the presence of ammonium chloride concurrent with ammonium sulfate. Hindman et al. ( 4 ) found relatively few particles that were only sodium chloride; most of the particles consisted of many elements and compounds, including sulfur forms. For the most part, the role of HC1 in the atmosphere has all but been ignored. Most investigators discount the direct emission of HC1 associated with the burning of fossil fuels, although in oil the amount of available chloride for emission can be linked not only to that inherent in the fuel but also to the amount of excess water in the fuel. The latter is related to sea water, most probably the residual of tanker ballast or wash water, and can be highly variable. The creation of HC1 in the atmosphere is generally assumed to be a breakdown of sea salt (NaCl) by photooxidation with nitrogen dioxide (5, 6) along with aldehydes (12) or through sulfate reactioins (6, 7 ) .A more complex relationship is pro-
jected by Yue and Mohnen (8) for the production of HC1 in clouds. They show that the amount of HC1 released from an aqueous system depends, in part, on the ambient concentraand H2S04, as well as the liquid water tions of S02, ”3, content available in the cloud. The production of HC1 increases with the amount of SO2 available but is limited by the This suggests a competition betyeen HC1 and increase of “3. sulfate for the available NH3 as is also implied by Cunningham et al. ( 3 ) and Brosset et al. ( 7 ) . The production of HC1 in an aqueous acidic system is based on the fact that SO2 can be absorbed and converted to S042-. As the concentration of S04*- increases either through production or evaporation, the solution vapor pressure will approach that of sulfuric acid. Since the vapor pressure of sulfuric acid is less than that of hydrochloric acid, as the reduction proceeds past the equilibrium point between the two, HC1 will be driven from the system (followed by nitric acids, if present). Whether or not the system is driven to total HC1 depletion is not now relevant. However, the important question to be answered is what happens to the HC1 aerosol so produced in accordance with the scenario or by direct emission from combustion sources. Rollins and Homoloya (1)have suggested a transformation of HC1 into ammonium chloride. This suggests a complex role for HC1 that relates directly to the creation of strong acid aerosols and aqueous sites suitable for the conversion of SO2
0013-936X/80/0~914-1149$01.00/0 @ 1980 American Chemical Society
Volume 14,Number 9,September 1980 1149
to sulfates and sulfuric acid premised on the fact that most chlorides are deliquescent. Twomey (9) and Orr et al. (IO, 11) have investigated changes that occur with various deliquescent compounds. They developed a methodology to predict the relative humidity necessary to change a dry particle into a liquid aerosol and the size changes that will result. They also predicted the point a t which such liquid aerosols would revert to solids. Hindman et al. ( 4 ) have observed growth and aerosol size distribution alterations, which they attributed to deliquescent particles. Fenton and Ranade (13) indicated that aerosol growth promoted by the presence of HCl in a humid system may be attributable to the hygroscopic properties of HC1 vapor. With deliquescence as a key, a cycle is hypothesized as follows: nondeliq. metallic oxide
+ HC1-
deliq. metallic chloride
+ H20
-
Literature Cited
+ H20 + SO2 + 0 2 metallic ion + HzSO4 + S042- + HC1 + HzO metallic sulfate + H#04 + HC1+ H2Ot metallic sulfate + HzS04 + HClf deliq. metallic chloride
1- HC1+
nondeliq. metallic oxide
+
-
A number of statements can be made relative to this hypothesis and its implications: The creation of mixed acid solutions with significantly low vapor pressure will result in the effervescence of free hydrochloric and possibly nitric acids. Chlorides through their deliquescent property will generate acidic liquid film particulates and liquid aerosols in all size ranges that are conducive to the absorption of SO2 with subsequent conversion of sulfites to sulfuric acid, which may in due course lead to the effervescence of HC1. Hydrochloric acid absorbed in sufficient abundance in a metallic solution can create a deliquescent droplet that can, upon absorbing atmospheric water vapor, provide sites conducive to later formation of strong low vapor pressure acids. Hydrochloric acid impinging on the surface of dry particulate can begin to dissolve its substrate, convert to a deli-
1150
Environmental Science & Technology
quescent particle, absorb water vapor, and provide an environment conducive to the formation of strong low vapor pressure acids. The atmospheric recyclability role hypothesized for HC1 gave it characteristics of a catalyst for the formation of atmospheric sulfuric acid and sulfate compounds. Since the recycling of HC1 is an ongoing process requiring moisture and excess SO2, it is not restricted by distance from a single known source. It may reach an equilibrium at any time and begin again when the equilibrium is upset. Thus, by the hypothesized role of recyclability, a relatively small amount of chloride or HC1 would have a disproportionate effect. Perhaps HC1 may be the missing link in the formation of sulfate species in the atmosphere. It is an aspect that should be considered. Response to this hypothesis would be appreciated.
(1) Rollins, R., Homolya, J. B., Enuiron. Sci. Technol., 13, 1380-3 (1979). (2) Carotti, A. A., Kaiser, E. R., J . Air Pollut. Control Assoc., 22(4), 248-53 (1972). (3) . . Cunnineham. P. T.. Johnson. S. A.., Yane. R. T.. Enuiron. Sci. Technol.,-b, 131-4 (1974). (4) Hindman. E. E., Hobbs, P. V., Radke, L. F., J. Air Pollut. Control ASSOC., 27(3), 224-9 (1977). (5) Robbins, R. C., Cadle, R. D., Eckhardt, D. L., J.Meteor., 16(1), 53-6 (1959). (6) Cadle, R. D., J. Colloid Interface Sci., 39(1), 25-31 (1972). (7) Brosset, C., Andreasson, K., Ferm, M., Atmos. Enuiron., 9(6/7), 631-42 (1975). (8) Yue, G. K., Mohnen, V. A., “Proceedings of the 1st International Symposium on Acid Precipitation and the Forest Ecosystem,” USDA, Forest Service, General T.R. NE-23,1976, P B 258 645, pp 181-203. (9) Twomey, S., J . Meteor., 11(4), 334-8 (1954). (10) Orr, C., Hurd, F. K., Corbett, W. J., J . Colloid Sci., 13,472-82 (1958). (11) Orr, C., Hurd, F. K., Hendrix, W. P., Junge, C., J. Meteor., 240-2 (1958). (12) Hanst, P. L., Gay, B. W., Enuiron. Sci. Technol., 11, I (19771 .,. \ _ l .
(13) Fenton, D. L., Ranade, M. B., Enuiron. Sci. Technol., 10,1160-2 (1976).
Edward J. Kaplin York Research Corporation One Research Drive Stamford, Conn. 06906
