RESEARCH WATCH Air 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, 23(6), 370-384)
Biodegradation Benzene decomposition. Benzene in methanogenic sediments was rapidly converted, without an apparent lag, to methane and carbon dioxide. (Weiner, J. M.; Lovley, D. R. "Rapid Benzene Degradation in Methanogenic Sediments From a PetroleumContaminated Aquifer," Appl. Environ. Microbio.. 1998, 64(5), 19371939) Dioxin dechlorination. The increase of 2,3,7,8-TCDD may result from combined biotic and abiotic PCDD dechlorination. (Barkovskii, A. L.; Adriaens, P. "Impact of Humic Constituents on Microbial Dechlorination of Polychlorinated Dioxins," Environ. Toxicol. Chem. 1998, i7(6), 1013-1020) PCB dechlorination. Initial, rapid dechlorination of PCBs in sediments is followed by slow transformations that contribute very little to the overall extent of reaction. (Sokol, R. C ; Bethoney, C. M.; Rhee, G-Y. "Reductive Dechlorination of Preexisting Sediment Polychlorinated Biphenyls With Long-Term Laboratory Incubation," Environ. Toxicol. Chem. 1998, 2 7(6), 982-987)
Bioremediation BTEX cleanup. Use of a bioluminescence-based bacterial biosensor in the management of contaminated sites reduces site remediation costs. (Sousa, S.; Duffy, C; Weitz, H.; Glover, L. A.; Bar, E.; Henkler, R.; Killham, K. "Use of a Lwx-Modified Bacterial Biosensor to Identify Con-
Aquatic colloid interactions Submicron colloids, ubiquitous in natural waters, play a crucial role in pollutant cycling and transport—often, 40-90% of trace compounds may be adsorbed on colloids. J. Buffle and coworkers reviewed and synthesized information about natural colloids in aquatic systems and concluded that colloidal aggregate formation in aquatic systems can be understood in terms of three colloid types: inorganics, large rigid biopolymers, and fulvic-type compounds. Modes of aggregation that involve the three colloid groups are described. Fulvic compounds stabilize inorganic colloids, whereas rigid biopolymers have the opposite effect. The concentration of stable colloids in natural water depends on relative amounts present and interactions of these three colloid types. {Environ. Sci. Techno!., ,his iisue, ,p. .287-2899)
straints to Bioremediation of BETEXContaminated Sites," Environ. Toxicol. Chem. 1998, 17(6), 10391045) Fuel components. Total removal of residual hydrocarbons in fuel-contaminated aquifers is not required to counteract sediment toxicity. (Hutchins, S. R.; Bantle, I. A.; Schrock, E. ]. "Effect of Nitrate-Based Bioremediation on Contaminant Distribution and Sediment Toxicity: Column Study," Environ. Toxicol. Chem. 1998, i7(3), 349-361)
Contaminants Metal transport. Metal source characteristics and hydrologic factors affected the transport of metal contaminants in an urbanized watershed. (Solo-Gabriele, H. M. "Generation of Long-Term Record of Contaminant Transport," /. Environ. Eng. 1998, 124(7), 619-627) Organochlorine impacts. Elevated levels of PCBs and mercury in smallmouth bass are of concern because the fish are consumed by eagles and mink. (Henry, K. S.; Kannan, K.; Nagy, B. W.; Kevern, N. R.; Zabik, M. I.; Giesy, ]. P. "Concentrations and Hazard Assessment of Organochlorine Contaminants and Mercury in Smallmouth Bass From a Remote Lake in the Upper Peninsula of Michigan," Arch. Environ. Contam. Toxicol. 1998, 34(1), 81-86)
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Drinking water Parasite detection. The development and validation of a method for detection of Toxoplasma gondii oocysts is described. (Isaac-Renton, I.; Bowie, W. R.; King, A.; Irwin, G. S.; Ong, C. S.; Fung, C. P.; Shokeir, M. O.; Dubey, J. P. "Detection of Toxoplasma gondii Oocysts in Drinking Water," Appl. Environ. Microbiol. 1998, 64(5), 2278-2280)
Groundwater Nitrate removal. A denitrification wall consisting of soil and sawdust effectively removed N 0 3 from groundwater. (Schipper, L.; VojvodicVukovic, M. "Nitrate Removal From Groundwater Using a Denitrification Wall Amended With Sawdust: Field Trial," /. Environ. Qual. 1998, 27, 664-668)
Health Health endpoints. Ambient PM 10 concentrations can be used in epidemiologic studies that seek to link variations in particulate matter concentrations to variations in health endpoints. (Janssen, N.A.H.; Hoek, G.; Brunekreef, B.; Harssema, H.; Mensink, I.; Zuidhof, A. "Personal Sampling of Particles in Adults: Relation Among Personal, Indoor, and Outdoor Air Concentrations," Am. J. Epidemiol. 1998, i47(6), 537547)
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