RESEARCH WATCH

Air Dioxins in the Great Lakes. Atmo­spheric deposition is the dominant source of dioxins in Lake Superior but not in Lakes Michigan and On­tario. (Pearson, R. E; Swackhamer, D. L.; Eisenreich, S. J.; Long, D. T. "Atmospheric Inputs of Polychlori-nated Dibenzo-p-dioxins and Diben-zofurans to the Great Lakes: Compo­sitional Comparison of PCDD and PCDF in Sediments," /. Great Lakes Res. 1998, 24(1), 65-82)

Biodegradation Bacteria survival. In sites heavily polluted by aromatic hydrocarbons, solvent-tolerant bacterial strains are first established and play a predomi­nant role in removing contaminants. (Huertas, M-J.; Duque, E.; Marques, S.; Ramos, J. L. "Survival in Soil of Differ­ent Toluene-Degrading Pseudomonas Strains After Solvent Shock," Appl. En­viron. Microbiol. 1198, 64(1), 38-42)

Biodegradation kinetics. The mixed microbial community [AU: Delete "community"?] biodegradation ki­netics of an organic compound by biomass that simultaneously de­grades a mixture of substrates were quantified. The influence of the mul­tiple substrates was elucidated. (El­lis, T. G; Barth, E S.; Grady Jr., C.P.L. "Effect of Simultaneous Biodegrada­tion of Multiple Substrates in the Extant Biodegradation Kinetics of Individual Substrates," Water Envi­ron. Res. 1998 70(1) 27-38)

Competitive bacteria. Cometabolic degradation of trichloroethylene has a negative effect on the maintenance and competitive behavior of tolu­ene-utilizing organisms that trans­form the chloro-organic compound. (Mars, A. E.; Prins, G. T; Wietzes, P.; De Koning, W.; Janssen, D. B. "Effect of Trichloroethylene on the Compet­itive Behavior of Toluene-Degrading Bacteria," Appl. Environ. Microbiol. 1998, 64(1), 208-215)

Climate change N2O emission from plants. Results demonstrate a mechanism for N20 emission from upland crops and im­ply that measurement of N20 release solely from the soil surface may un­derestimate fluxes from agroecosys-tems. (Chang, C; Janzen, H. H.; Cho, C. M.; Nakonechny, E. M. "Nitrous Oxide Emission Through Plants," Soil Sci. Soc. Am. J. 1998, 62(1)) 35-38)

The missing carbon sink. An analy­sis was performed to distinguish be­tween mechanisms likely to act as feedbacks to global warming and otiier mechanisms consistent with a terrestrial sink that are not feed­backs to a global warming. (Hough­ton, R. A.; Davidson, E. A.; Woodwell, G. M. "Missing Sinks, Feedbacks, and Understanding the Role of Terrestrial Ecosystems in the Global Carbon Balance," Global Biogeochem. Cycles 1998 72(1) 25-34)

Health Endocrine disrupter effects in mice. Administration of small doses of chemicals used in the manufacture of plastics and other products dis­rupts the development of sociosex-ual behavior as well as size and functioning of reproductive organs in mice. (Vom Saal, F. S., et al. "A Physiologically Based Approach to the Study of Bisphenol A and Other

Estrogenic Chemicals on the Size of Reproductive Organs, Daily Sperm Production, and Behavior," Toxicol. Ind. Health 1998, i4(l), 239-260)

Pollution and hiking. Hikers with past asthma and related health problems who are exposed to ozone and other pollutants have significant changes in pulmonary function. (Korrick, S. A.; et al. "Effects of Ozone and Other Pollutants on the Pulmonary Function of Adult Hik­ers," Environ. Health Perspect. .998, 706(2), 93-99)

Indoor air Household mold sources. Most mold growth occurs in hidden loca­tions, and household moisture sources are a more significant factor in determining mold levels than is relative humidity. (Lawton, M. D.; Dales, R. E.; White, J. "The Influence of House Characteristics in a Cana­dian Community on Microbiological Contamination," Indoor Air 1998, 8, 2-11)

Measurements Dioxin detection method. The de­velopment of a highly sensitive di­oxin detection technique is demon­strated. The influence of physical and chemical factors upon the anal­ysis outcome was investigated. (Sug-awara, Y; Gee, S. J.; Sanborn, J. R.; Gilman, S. D.; Hammock, B. D.

0013-936X/98/0932-375A$15.00/0 © 1998 American Chemical Society AUG. 1, 1998/ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS " 3 7 5 A

Pollutant uptake in soils The binding of hydrophobic organic compounds on or into natural organic matter can impair contaminant soil and sediment remediation efforts. W. Schlebaum and coworkers performed a kinetic study of the association of pentachlorobenzene with humic acid to understand the dynamics of the binding process. Results indicated the presence of labile (fast-desorbing) and nonlabile (slow-desorbing) pollutant frac­tions. Modeling of the binding process was attempted using first-order and Lang-muir models. Neither model completely described the experimental data. Discrepan­cies were attributed to an irreversible entrapment process resulting in occurrence of the nonlabile fraction. The authors suggested that entrapment is due to a confor­mational change in the humic acid macromolecules from an open to a more rigid structure. (Environ. Sci. Technol..,his issue, pp. 2273-2277)