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(23) Tsunogai, S.; Yonemaru, I.; Kusakabe, M. Geochem.J. 1979, 13, 239-252. (24) Kadko, D.; Heath, G. R. J. Geophys. Res. 1984, 89, 6567-6570. (25) Graybeal, A. L.; Heath, G. R. Geochim. Cosmochim.Acta 1984, 48, 965-975. (26) Wetzel, R. G. “Limnology”;Saunders: Philadelphia, 1975. (27) Tipping, E. Chem. Geol. 1981, 33, 81-89. (28) Jones, B. F.; Bowser, C. J. In “Lakes: Chemistry, Geology, Physics”;Lerman, A., Ed.; Springer-Verlag: New York, 1978; p 179-235. (29) Berrang, P. G.; Grill, E. V. Mar. Chem. 1974,2, 125-148. (30) Tipping, E.; Heaton, M. J. Geochim. Cosmochim.Acta 1983, 47, 1393-1397. (31) Edgington, D. N.; Robbins, J. A. Enuiron. Sci. Technol. 1976,10,266-274. (32) Hamilton-Taylor, J. Environ. Sci. Technol. 1979, 13, 6a3-697. (33) Nriagu, J. 0.; Wong, H. K. T.; Coker, R. D. Environ. Sci. Technol. 1982,16,551-560. (34) Gorham, E.; Swaine, D. J. Limnol. Oceanogr. 1965, I O , 268-279. (35) Carignan, R.; Flett, R. J. Limnol. Oceanogr. 1981,361-366. (36) Carignan, E.; Nriagu, J. 0. Geochim. Cosmochim. Acta 1985, 49, 1753-1764.
Received for review May 20, 1985. Accepted October 7, 1985.
CORRESPONDENCE 19, 552-557.
Comment on “Acidification of Southern Appalachian Lakes”
Alan W. Katzenstein
SIR: R. W. Talbot and A. W. Elzerman, writing on the acidification of southern Appalachian lakes (I),note that “S042-concentrations have been increasing over the past decade (in streams) in this region of the United States”, and comment that “because this trends seems to be similar historically to regional atmospheric emission patterns of SOz and NO,, the increased S042-concentrations may be related to inputs of acidic atmospheric deposition.” The authors do not make clear whether it is the acidity or the sulfate content of the “acidic atmosphere deposition” that might account for the increase in sulfate concentrations in surface waters. However, the data in their report shows no relationship between sulfate and acidity in the lake waters surveyed. The correlation coefficient for the data on sulfate and acidity, transformed from pH to hydrogen ion concentration, in the 10 lakes covered in their Table I, is r = -0.26. Initially, this might suggest that acidity and sulfate are negatively correlated. However, the correlation coefficient is not statistically significant, from which it must then be inferred that acidity and sulfate are not related a t all in this data set. The same lack of relationship-widely varying coefficients,both positive and negative-have been noted for other data sets on lake water acidity, leading to the broader conclusion that the alleged linkage between sulfate and acidity does not generally exist. Literature Cited (1) Talbot, R. W.; Elzerman, A. W. Environ. Sci. Technol. 1985, 302
Environ. Sci. Technol., Vol. 20, No. 3, 1986
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SIR: A. W. Katzenstein’s correspondence concerning our note ( I ) raises the point that there is a complicated relationship between atmospheric deposition and surface water concentrations of acidity and sulfate, as others have observed and we discuss in the note. Correlations between acidity and sulfate concentrations in atmospheric deposition have been observed (2). Temporal trends in sulfate concentrations in surface waters of the region are less well-established, but as referenced in our note ( I ) , there is evidence they have increased (3). Katzenstein’s conclusion that sulfate and acidity are not related in our data set (I) relies on the lack of a correlation between H+and Sot- concentrations in various surface waters. Clearly, such a simple relationship would not be expected, as H+ and S042-exhibit different “reactivities” in natural systems. The work of Cronan et al. ( 4 ) ,Burns et al. (5), and Galloway et al. ( 6 ) ,for example, indicates the local hydrogeology and interaction of rain water H+and S O P with watershed rocks and soils profoundly influence the resultant surface water composition (e.g., the concentrations of H+, Sod2-, HC03-, and base cations). As discussed in our note ( I ) , our data for several aquatic systems in the southeastern United States support this hypothesis and also suggest, like other available research results, that specific characteristics of the watershed are very important in determining surface water composition. Moreover, the model of Galloway et al. (6), describing surface water
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0 1986 American Chemical Society
