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 Polychlorinated Dibenzo-p-dioxins and Dibenzofurans to the Great Lakes: Compositional Comparison of PCDD and PCDF in Sediments," /. Great Lakes Res. 1998, 24(1), 65-82)
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 Langmuir 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)
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 N 2 0 emission from upland crops and imply that measurement of N 2 0 release solely from the soil surface may underestimate fluxes from agroecosystems. (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)
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
Health
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)
Endocrine disrupter effects in mice. Administration of small doses of chemicals used in the manufacture of plastics and other products disrupts the development of sociosexual 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
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. (Sugawara, 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
Measurements
AUG. 1, 1998/ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS " 3 7 5 A
