RESEARCH WATCH Air Aircraft emissions. Current knowledge of atmospheric processes is described, and potential atmospheric effects of aircraft emissions are analyzed. (Brasseur, G. P.; Cox, R. A.; Hauglustaine, D.; Isaksen, I.; Lelieveld, J.; Lister, D. H.; Sausen, R.; Schumann, U.; Warmer, A.; Wiesen, R "European Scientific Assessment of the Atmospheric Effects of Aircraft Emissions," Atmos. Environ. 1998, 32(13), 2329-2418) Particulate matter. Population exposure to particulate matter in all size ranges improved during the period 1940-1990. (Lipfert, F. W. "Trends in Airborne Particulate Matter in the United States," Appl. Occup. Environ. Hyg. 1998, 73(6), 370-384)
Biodegradation Chlorophenols. A newly isolated bacterium was used to successfully biodegrade chlorophenols in water. (Steinle, R; Stucki, G.; Stettler, R.; Hanselmann, K. W. "Aerobic Mineralization of 2,6-dichlorophenol by Ralstonia Sp. Strain Rkl," Appl. Environ. Microbiol. 1998, 64(7), 2566-2571) Sediment effects. The presence of sediments can affect the biodegradation patterns of mixtures of PAHs. (Beckles, D. M.; Ward, C. H.; Hughes, J. B. "Effect of Mixtures of Polycyclic Aromatic Hydrocarbons and Sediments on Fluoranthene Biodegradation Patterns," Environ. Toxicol. Chem. 1998, 17(7), 1246-1251)
Climate change Carbon sinks. The long-term variability of anthropogenic carbon in terrestrial and oceanic uptake was studied. (Joos, E; Bruno, M. "LongTerm Variability of the Terrestrial and Oceanic Carbon Sinks and the Budgets of the Carbon Isotopes 13C and 14C," Global Biogeochem. Cycles 1998, 12{2), 277-295)
Dissolution of cinnabar by DOM Dissolved organic matter (DOM) interacts with cations in natural waters and soils and affects solubility, mobility, and toxicity of many trace metals. M. Ravichandran and coworkers found that organic matter isolated from the Florida Everglades caused a dramatic increase in mercury release from cinnabar (HgS). Hydrophobic acids dissolved more mercury than hydrophilic acids and other DOM nonacid fractions. Possible mechanisms of dissolution include surface complexation of mercury and oxidation of surface sulfur species by the organic matter. DOM enhances mercury release from cinnabar under oxic and anoxic conditions. Enhanced cinnabar solubility has geochemical significance: In mercury-contaminated areas and where conditions favor HgS formation, humic substances could enhance mercury mobilization and affect bioavailability. (Environ. Sci. Techno!., ,his issue, pp. 3305-3311)
Model test. The performance of three global ocean carbon cycle models is evaluated, and deficiencies are noted. (Stephens, B. B.; Keeling, R. E; Heimann, M.; Six, K. D.; Murnane, R.; Caldeira, K. "Testing Global Ocean Carbon Cycle Models Using Measurements of Atmospheric 0 2 and Co2 Concentration," Global Biogeochem. Cycles 1998, 12{2), 213-230) Sensitivity study. A model was used to examine the responses of terrestrial ecosystems to transient changes in atmospheric C0 2 concentration and climate in the 21st century. (Xiao, X.; Melillo, J. M.; Kicklighter, D. W; McGuire, A. D.; Prinn, R. G.; Wang, C; Stone, P. H.; Sokolov, A. "Transient Climate Change and Net Ecosystem Production of the Terrestrial Biosphere," Global Biogeochem. Cycles 1998, 12(2), 345-360)
Contaminants Contaminant accumulation. A review is presented of methods used to measure or predict the accumulation of persistent organic contaminants in plants and animals. (Burnison, B. K. "Review of Bioconcentration, Bioaccumulation and Kow Techniques," Water Qual. Res. J. Can. 1998, 33(2), 213-230) Novel discovery. Compounds that are structurally isomeric with dioxins have been found in thermal process-
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ing streams. (Otto, E; Leupold, G.; Parlar, H.; Rosemann, R.; Bahadir, M.; Hopf, H. "Chlorinated Diphenoquinones: A New Class of Dioxin Isomeric Compounds Discovered in Fly Ashes, Slags, and Pyrolysis Oil Samples by Using HPLC/ELCD and HRGC/MS," Anal. Chem. 1998, 70(4), 2831-2838) Volatile organic compounds. This report reviews the characteristics of various processes that could affect the transport, behavior, and fate of 55 VOCs in streams. (Rathbun, R. E. "Transport, Behavior, and Fate of Volatile Organic Compounds in Streams," U.S. Geol. Surv. Prof. Pap. 1998, 1589, 151 pp.)
Control Bacterial insecticide. Bacterial strains are shown to have use in controlling mosquito larvae. (Orlova, M. V; Smirnova, T A.; Ganushkina, L. A.; Yacubovich, V Y.; Azizbekyan, R. R. "Insecticidal Activity of Laterosporus," Appl. Environ. Microbiol. 1998, 64(7), 2723-2725)
Drinking water Cancer mortality. The results of this study suggest a positive association between chlorinated drinking water consumption and cancer of the rectum, lung, bladder, and kidney. (Yang, C-Y; Chiu, H-E; Cheng, M-E; Tsai, S-S. "Chlorination of Drinking
0013-936X/98/0932-510AS15.00/0 © 1998 American Chemical Society
Water and Cancer Mortality in Taiwan," Environ. Res. 1998, 78(1), 1-6) Contamination vector. Results indicate that birds can act as mechanica carriers of infectious oocysts that can be disseminated in the environment, including drinking water supplies. (Graczyk, T. K.; Fayer, R.; Trout, J. M.; Lewis, E. J.; Farley, C. A.; Sulaiman, I.; Lai, A. A. "Giardia Sp. Cysts and Infectious Cryptosporidium parvum Oocysts in the Feces of Migratory Canada Geese {Branta Canadensis)," Appl. Environ. Microbiol. 1998, 64(7), 2736-2738)
Health Fungus contamination. A causal connection between fungal exposure and health is supported. (Dales, R.; Miller, D.; White, J.; Dulberg, C ; Lazarovits, A. I. "Influence of Residential Fungal Contamination on Peripheral Blood Lymphocyte Populations in Children," Arch. Environ. Health 1998, 53(3), 190-195) Hazardous air pollutants. Air toxics concentrations may pose a health problem. (Woodruff, T. J.; Axelrad, D. A.; Caldwell, J.; Morello-Frosch, R.; Rosenbaum, A. "Public Health Implications of 1990 Air Toxics Concentrations Across the United States," Environ. Health Perspect. 1998, 106(5), 245-251) Pentachlorophenol exposure. Health effects, such as chloracne and biochemical abnormalities, that are associated with pentachlorophenol production workers may persist for years after exposure. (Hryhorczuk, D. O.; Wallace, W. II.; Persky, V; Furner, S.; Webster Jr., J. R.; Oleske, D.; Haselhorst, B.; Ellefson. R.; Zugerman, C. "A Morbidity Study of Former Pentachlorophenol-Production Workers " Environ. Health Perspect. 1998, 106(7), 401-408)
Pollutants in aquatic systems It is difficult to determine the free concentration of pollutants in aqueous samples that contain dissolved organic carbon (DOC) because DOC is essentially inseparable from the aqueous phase. E. Ramos and colleagues investigated the utility of a negligible depletion solid-phase microextraction technique (SPME) for measuring the free concentrations of highly hydrophobic chemicals in aquatic samples containing humic acids. They found that by minimizing the depletion, the method could be used to determine water/DOC partition coefficients and the freely dissolved (bioavailable) fraction of hydrophobic organic pollutants Use of the nondepleting SPME method minimized perturbation of equilibrh in the natural matrix {Environ Sci Technol this issHP nn 3430-3435)
Sediments Carbon transport. Linkages between the carbon cycle and sedimentary processes on land were examined. (Stallard, R. F. "Terrestrial Sedimentation and the Carbon Cycle: Coupling Weathering and Erosion to Carbon Burial," Global Biogeochem. Cycles 1998, 12(2), 231-257)
Soils Biofilm behavior. Packed-bed reactors were used to examine the effects of electric charge and molecular size on biofilm sorption of organic compounds selected for their similarity to the size and charge ranges of aquatic natural organic matter. (Carlson, G.; Silverstein, J. "Effect of Molecular Size and Charge on Biofilm Sorption of Organic Matter," Water Res. 1998, 32(5), 1580-1592)
Monitoring Tobacco smoke. Environmental tobacco smoke is shown to contribute significantly to toxic air contaminant exposure. (Miller, S. L.; Branoff, S.; Nazaroff, W W "Exposure to Toxic Air Contaminants in Environmental Tobacco Smoke: An Assessment for California Based on Personal Monitoring Data," /. Exposure Anal. Environ. Epidemiol. 1998, 8(3), 287-311)
Heavy metals. Sorption processes in tropical soils are reviewed. (Naidu, R.; Sumner, M. E.; Harter, R. D. "Sorption of Heavy Metals in Strongly Weathered Soils: An Overview," Environ. Geochem. Health 1998, 20(1), 5-9)
Toxicology Carcinogens. There are more rodent liver carcinogens than were identified
by the National Toxicology Program. (Crump, K. S.; Krewski, D.; Wang, Y. "Estimates of the Number of Liver Carcinogens in Bioassays Conducted by the National Toxicology Program," Risk Anal. 1998, 18(3), 299-308) Predicting toxicity. Quantitative shape-activity relationship modeling provides good correlations between experimental toxicity and molecular shape features of PAH molecules. (Mezey, P G.; Zimpel, Z.; Warburton, P.; Walker, P. D.; Irvine, D. G; Huang, X-D;; Dixon, D. G.; Greenberg, B. M. "Use of Quantitative Shape-Activity Relationships to Model the Photoinduced Toxicity of Polynuclear Aromatic Hydrocarbons: Electron Density Shape Features Accurately Predict Toxicity" Environ. Toxicol. Chem. 1998 17(7) 1207-1215)
Wastewater Phosphorus bioavailability. Total phosphorus in purified municipal wastewaters is not a sufficient criterion for establishing eutrophication control measures. (Elkholm, R; Krogerus, K. "Bioavailability of Phosphorus in Purified Municipal Wastewaters," Water Res. 1998, 32(2), 343-351) Phosphorus removal. Conditions are described by which good biological phosphorus removal was accomplished in a sequencing batch reactor. (Stephens, H.; Stensel, H. "Effect of Operating Conditions on Biological Phosphorus Removal," Water Environ. Res. 1998, 70(3), 362-369) Roadway runoff. Results provide guidance for assessing the impact of urban runoff and treatment strategies. (Sansalone, J.; et al. "Physical Characteristics of Urban Roadway Solids Transported During Rain Events," /. Environ. Eng. 1998, 124(5), 427-440) Contributors: Michael Brauer, University of British Columbia, Vancouver, Canada; Brian Eitzer, Connecticut Agricultural Experiment Station, New Haven, Conn.; Stephen Geiger, Remediation Technologies, Inc., King of Prussia, Pa.; Vincent Hand, Miami University, Institute of Environmental Sciences, Oxford, Ohio; Louis Kovach, Ecolife Associates, Wilmington, Dei; and Raewyn Town, Queen's University of Belfast, Northern Ireland.
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