Environ. Sci. Technol. 1985, 19, 871-871
Literature Cited
Registry No. Carbon, 7440-44-0.
(1) Dorward, E. J.; Barisas, B. G. Environ. Sei. Technol. 1984,. 18,967-972.
Literature Cited Porter, W. R. Environ. Sci. Technol., preceding paper in this issue. Cornish-Bowden, A. “Principles of Enzyme Kinetics”; Butterworths: Boston, 1979. Weber, W. J., Jr., “Physicochemical Processes for Water Quality Control”; Wiley: New York, 1972. Gaudy, A. F., Jr.; Gaudy, E. T. “Microbiology for Environmental Scientists and Engineers”; McGraw-Hill: New York, 1980. Corwin, D. L.; Farmer, W. J. Environ. Sci. Technol. 1984, 18, 507-514. Dalang, F.; Buffle, J.; Haerdl, W. Environ. Sci. Technol. 1984, 18, 135-141.
Richard W. Walters”
Department of Civil Engineering University of Maryland College Park, Maryland 20742 Rlchard G. Luthy
Department of Civil Engineering Carnegie-Mellon University Pittsburgh, Pennsylvania 152 13
Comment on “Acute Toxicity Screening of Water Pollutants Using a Bacterial Electrode” S I R This concerns an article by Dorward and Barisas ( I ) that was recently published in ES&T. First, I do not understand the basis for the apparent inconsistent comparison of three methods of measuring acute toxicity of materials in aquatic systems. For two of the methods (fish tests and bioluminescent bacteria tests), results are reported as median-effect concentrations (LC5O’s and EC50’s, respectively). For the authors’ proposed method with Escherichia coli, however, “inhibition levels of 40% were chosen...” It seems to me an arbitrary and illogical choice, one that serves only to bring the E . coli test results more in line with fish and bioluminescent bacteria test results. Second, because only 7 of the 12 substances tested with E. coli “...yielded dose [concentration]-effect relationships which have provided useful toxicological information”, I question the validity of the proposed method. A test that produces useful information
