Research Watch
Atmosphere Air-surface exchange. A method for estimating bidirectional air-surface exchange of elemental mercury was developed that calculates emission and dry deposition for specified land cover, meteorological data, and mercury concentrations. (Xu, X., et al. "Formulation of Bi-directional Atmosphere-Surface Exchanges of Elemental Mercury", Atmos. Environ. 1999, 33 (27), 4345-4355) Atmospheric behavior. This report, which includes 130 references, reviews the atmospheric transport and dispersion of currenuy used pesticides and discusses deposition, vapor phaseparticle phase partitioning, seasonal and spatial variations, transformation products, pesticides in surface water due to atmospheric transport, and source-receptor relationships. (Van Dijk H.F.G.; Guicherit, R. "Atmospheric Dispersion of Current-Use Pesticides: A Review of the Evidence From Monitoring Studies" Water Air Soil Pollut 1999 115 (1-4) 21-70) Risk assessment. Experts identified current knowledge about the fate of pesticides in the atmosphere and possible approaches for their regulatory environmental risk assessment. (Guicherit, R., et al. "Environmental Risk Assessment for Pesticides in the Atmosphere; The Results of an International Workshop", Water, Air, Soil Pollut. 1999, 115 (1-4), 5-19)
Climate Hydrofluoro(poly)ethers. Global warming potentials and calculations of atmospheric lifetimes based on reaction with OH radicals are presented for CHF2OCHF2, CHF2OCF2OCHF2, CHF2OCF2CF2OCHF2, and for CHF2OCF2OCF2CF2OCHF2. (Myhre, G., et al. "Infrared Absorption Cross
Huge dioxin emission source In many areas of the United States, households dispose of waste by burning it in open barrels, often in their backyards. It is expected that dioxins can be produced in significant quantities when garbage is burned in this manner, given the range of combustion conditions that can occur. P. Lemieux and co-workers evaluated this practice and found that backyard burning emits more PCDDs/PCDFs on a mass-ofrefuse-burned basis than various types of municipal waste combustors (MWCs). Results indicate that about 2-40 households burning their trash in barrels can produce average PCDD/PCDF emissions comparable to a 200 ton/day MWC facility equipped with high-efficiency flue gas-cleaning technology. (Environ. Sci. .echno]., this issue, pp. 377-384)
Section, Radiative Forcing, and GWP of Four Hydrofluoro (poly) ethers", Atmos. Environ. 1999, 33 (27), 4447-4458) Temperature change. Variations in the 29 N 2 / 28 N 2 ratio of air bubbles trapped in polar ice cores and their relation to variations of the 1 8 0 / l 6 0 of the ice allow past surface temperature variations and Ice Age-gas age differences to be determined. (Lang, C , et al. "16 °C Rapid Temperature Variation in Central Greenland 70,000 Years Ago", Science 1999, 286 (5441), 934-937)
Contaminants PCB exposures. The chemical distribution among fat, chorioallantoic membrane (CAM), and residual yolk tissue of live neonatal American alligators is evaluated to assess the potential utility of CAM use as a nonlethal indicator of exposure to PCBs. (Bargar, T. A., et al. "Relative Distribution of Polychlorinated Biphenyls Among Tissues of Neonatal American Alligators (Alligator mississippipiensis)", Arch. Environ. Contain. Toxicol. 1999 37 (3), 364-368) PCBs in frogs. Concentrations of polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans in northern leopard frogs are measured, and
the catalytic activity of hepatic cytochrome P 450-associated monooxygenase as a biomarker for exposure to aryl hydrocarbon receptor agonists is explored. Huang, Y.-W., et al. "Exposure of Northern Leopard Frogs in the Green Bay Ecosystem to Polychlorinated Biphenyls, Polychlorinated Dibenzo-p-dioxins, and Polychlorinated Dibenzofuransls Measured by Direct Chemistry but Not Hepatic Ethoxyresorufin-o-deethylase Activity", Environ. Toxicol. Chem. 1999, 18 (10), 2123-2130) Sonochemical treatment. The technological feasibility for using sonochemical processing to destroy organic contaminants is examined. (Suri, R. R S., et al. "Effect of Process Variables on Sonochemical Destruction of Aqueous Trichloroethylene", Environ. Eng. Sci. 1999, 1 6 (5), 345-342)
Metals Lead exposure in children. This investigation supports findings by others that the present HUD risk levels for lead in floor wipe samples may not be adequate for reducing children's blood lead levels below 10 mg/dL. (Sterling, D. A., et al. "Evaluation of Four Sampling Methods for Determining Exposure of Children to LeadContaminated Household Dust", Environ. Res. 1999 81 (2), 130-141)
FEBRUARY 1, 2000 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 9 1 A
