Environ. Sci, Technol. zyxwvu 1982. zyxwvu 16. zyxwvu 367-369 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJI Literature Cited zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Ferrante, J. G; Dettman, E. H.; Parker, J. I. Report ANL/ES-85; Argonne National Laboratory: Argonne, IL, 1980; p 61. “Standard Methods for the Examination of Water and Waste Water”, 14th ed.; APHA, AWWA, and WPCF New York, 1975. “Methods for Chemical Analysis of Water and Wastes”; U.S. Environmental Protection Agency: EPA-625-6-74-003a, 1974; p 298. Swinnerton, J. W.; Linnenbom, V. G.; Cheek, C. J. Anal. Chem. 1962,34,483. Swinnerton, J. W.; Linnenbom, V. G.; Cheek, C. J. Anal. Chem. 1962,34, 1509. Dettmann, E. H. Report ANL/ES-86; Argonne National Laboratory: Argonne, IL, 1980; p 21. Lawrence, M.; Schereer, E. Technical Report 520; Fisheries and Marine Service, Freshwater Institute: Winnipeg, Canada, 1974; p 47. Herbert, D. W. M.; Merkens, J. C. Int. J. Air Water Pollut. 1961, zyxwvutsrqp 5, 46. “Water Quality Criteria 1972”; NAS, NAE, USEPA Ecol. Res. Series,EPA-R3-73-033 Washington,D.C., 1973; p 594. Sherk, J. A.; O’Connor, J. M.; Neumann, D. A. Coastal Engineering Research Center Report 76-1; US. Army Corps of Engineers: Belvoir, VA, 1976; p 50. Hanks, K. S. J. Ariz. Acad. Sei. 1976, 11, 3. Robbins, J. A.; Edgington, D. N.; Kemp, A. W. L. Radio- logical and Environmental Res. Div. Ann. Rep. ANL-76-88, Part 111;Argonne National Laboratory: Argonne, IL, 1976; p 87. Howard, D. L.; Frea, J. I.; Pfister, R. M. Proc. Conf. Great Lakes Res. 1971, 14, 236. Zapotosky, J. E.; White, W. S. Report ANL/ES-87;Argonne National Laboratory: Argonne, IL, 1980; p 150. Frea, J. I.; Ward, T. E.; Mallard, G. E. Report 485; Water Resources Center: Ohio State University, Columbus, OH, 1977; p 153. Teal, J. M. “Fate and Effect of Petroleum Hydrocarbons in Marine Ecosystems and Organisms”; NOAA, USEPA: New York, 1977; p 71. Received for review July 13, 1981, Accepted February 25,1982. This study was financially supported by the zyx US. Army Corps of Engineers and the U.S. Environmental Protection Agency. Work was performed under the auspices of the US. Department of Energy. Biotransformation of PCB by Natural Assemblages of Freshwater Microorganisms Michael P. Shlarist and Gary S. Sayler” zyxwvuts Department of Microbiology and Graduate Program in Ecology, University of Tennessee, Knoxville, Tennessee 379 16 Natural mixed-microbial populations in lake water were found capable of oxidizing 2-chlorobiphenyl but not 2,4‘-dichlorobiphenyl. No evidence was found to indicate that these populations were able to oxidize a PCB mixture 54% chlorine by weight. Oxidation of 2-chlorobiphenyl resulted in the accumulation of two biotransformation products, chlorobenzoic acid and chlorobenzoylformic acid (chlorophenylglyoxylic acid). The results indicate that biodegradation of PCB congeners may result in the accu- mulation of environmentally stable chlorinated biotrans- formation products in aquatic environments. Introduction A number of reports have cited the ability of isolated heterotrophic bacteria to grow on and in some cases de- grade polychlorinated biphenyls (PCB) zyxwvut (1-7). There are also reports that natural assemblages of microorganisms are capable of PCB biodegradation (8-12), but little in- formation exists on the environmental biodegradative fate of PCB. Chlorinated biodegradation products have been suggested for trichlorobiphenyl in marine samples (8). A recent report has suggested that the terminal fate of zyxwvut p- chlorobiphenyl in a marine environment is mineralization accompanied by accumulation of benzoic acid (13). The objective of this brief report is to demonstrate that an alternate fate for PCB exists in aquatic environments. Problems associated with assessing the biodegradative fate of PCB in the environment are numerous and relate to low solubility, volatilization, photodecomposition, and sorption/desorption to living organisms and particulate ‘Present address: Department of Biology, University of Massa- chusetts, Boston Harbor Campus. matter. In addition, the position and degree of chlorination of the numerous congeners in commercial PCB mixtures, such as Aroclor 1254, modulates the biorecalcitrance of the PCB substrate. Consequently, gas-liquid chromatographic analysis of residual PCB following routine biodegradation assessment for removal of the substrate from terrestrial or aquatic samples is inexact and can only yield informa- tion pertaining to the potential interaction of the PCB with biotic components of a natural sample. As an example of this point, Table I represents a preliminary examination of PCB removal from aquatic samples exposed to PCB. These data are based on residual PCB quantitation using a previously described biodegradation assay, hexane ex- traction, and electron-capture GC analysis for PCB (14, 15). These results indicate a significant interaction of PCB with microbial populations present in a variety of tem- porally and spatially segregated samples from Center Hill Reservoir, T N (16). These data and the gas chromato- graphic profiles from which they are generated do little to assess the actual fate of PCB. In a further attempt to delineate the fate of PCB, the ability of microbial populations to mineralize PCB to COz was investigated. Some 10-mL Center Hill Reservoir samples were placed in 70-mL serum bottles to which 10 pL of repurified (Florisil column chromatography) [U- 14C]PCB (New England Nuclear, Boston, MA; 31.3 mCi/mmol, 54% chlorine by weight in mixture) in acetone was added. The reaction vessels were supplemented with 10 mg of prewetted powder XAD-4 resin (Supelco Inc., Bellefont,e,PA) to inhibit PCB volatilization. (Preliminary experiments indicated that XAD-4 resin had no effect on microbial growth and that naphthalene was mineralized in the presence of XAD-4 resin in the same experimental system.) l4COZ liberated from the PCB substrate was collected in a center-well NaOH C02 absorber. The ex- 0013-936X/82/0916-0367$01.25/0 0 1982 American Chemical Society Environ. Sci. Technol., Vol. 16, No. 6,1982 367