RESEARCH WATCH Air Missing NOx sink. Analysis of NOx source mechanisms implies that there are unidentified NOx sinks, because atmospheric models already overestimate stratospheric NO.,. concentrations. (Zipf, E. C; Prasad, S. S. "Evidence for New Sources of NOx in the Lower Atmosphere," Science 1998, 279(5348), 211-213) A global chlorine source. A process that occurs globally may act as a significant chlorine production source. (Oum, K. W.; Lakin, M. J.; DeHaan, D. O.; Brauers, T.; Finlayson-Pitts, B. J. "Formation of Molecular Chlorine From the Photolysis of Ozone and Aqueous Sea-Salt Particles," Science 1998, 279(5347), 74-76)
Biodegradation Bacterial degradation of gasoline oxygenates. The ability of propaneoxidizing bacteria to metabolize gasoline oxygenates is characterized. (Steffan, R. J., et al. "Biodegradation of the Gasoline Oxygenates Methyl ferr-Butyl Ether, Ethyl tert-Butyl Ether, and terr-Amyl Methyl Ether by Propane-Oxidizing Bacteria," Appl. Environ. Microbiol. 1997, 63(11), 4216-4222)
Bioavailability of heavy metals The complexity of metal accumulation by insect larvae cannot be characterized using one-compartment kinetic models. Moreover, the influence of complexing agents on metal bioavailability is not well characterized. C. Rouleau and coworkers used whole-body autoradiography and a two-compartment kinetic model to study the uptake, subsequent metabolism, and elimination of In2*, Cd2+, Hg2+, and CH3Hg by phantom midge larvae. The influence of two complexing agents, humic acid and sodium diethyldithiocarbamate, on metal uptake was studied. Uptake of CH3Hg, slower by a factor of 5 relative to Hg2+, was related to intracellular translocation processes for the organic metal species. The chelating agent sodium diethyldithiocarbamate enhanced uptake of Hg2+ and CH3Hg but had no effect on uptake of Cd2+ or Zn2+. Humic substances decreased Hgz+ uptake and increased CH3Hg uptake. (Environ. Sci. Techno!., this issue, pp. 1230-1236)
Sijm, D.T.H.M. "Physicochemical Properties of Polycyclic Aromatic Hydrocarbons: Aqueous Solubilities, n-Octanol/Water Partition Coefficients, and Henry's Law Constants," Environ. Toxicol. Chem. 1998, i7(2), 251-257)
Climate Change Carbon dioxide from forests. Rather than sequestering carbon dioxide, boreal forests may be a major source of this greenhouse gas, due to changes in climate that promote thaw and release carbon from soil. (Goulden, M. L., et al. "Sensitivity of Boreal Forest Carbon Balance to Soil Thaw," Science 1998, 279(5348), 214-217)
"Drinking Water Turbidity and Pediatric Hospital Use for Gastrointestinal Illness in Philadelphia," Epidemiology 1997, 8(6), 615-620)
Green Chemistry An environmentally benign catalyst. A novel, synthetic copper complex is described that can catalytically oxidize alcohols to aldehydes with oxygen under mild conditions. (Wang, Y.; DuBois, J. L.; Hedman, B.; Hodgson, K. O; Stack, T.DP. "Catalytic galactose oxidase models: Biomimetic Cu(II)-Phenoxyl-Radical Reactivity," Science 1998, 279(5350), 537540)
PAH biodegradation in soil. Naturally occurring soil microorganisms can extensively biodegrade benzo[ajpyrene under carefully controlled conditions. (Kanaly, R.; Bartha, R.; Fogel, S.; Findlay, M. "Biodegradation of [14C]benzo[a]pyrene Added in Crude Oil to Uncontaminated Soil," Appl. Environ. Microbiol. 1997, 63(11), 4511-4515)
Carbon reduction strategy. Technology and policy options are indicated for achieving substantial reductions in U.S. carbon emissions at low net cost to the nation. (Romm, J.; Levine, M.; Brown, M.; Petersen, E. "A Road Map for U.S. Carbon Reductions," Science 1998, 279(5351), 669-670)
Dietary calcium and lead. Evidence indicates that an increase in dietary calcium consumption can reduce lead absorption and toxicity. (Bogden, J. D.; Oleske, J. M.; Louria, D. B. "Lead Poisoning—One Approach to a Problem That Won't Go Away," Environ. Health Perspect. 1997, i05(12), 1284-1287)
Chemistry
Drinking Water
PAH physicochemical data. Physicochemical data needed for predicting the fate and effects of PAHs have been determined. (De Maagd, RG.-J.; Ten Hulscher, Dorien Th. E. M.; Van Den Heuvel, H.; Opperhuizen, A.;
Child health problems linked to water quality. Results show that serious gastrointestinal illnesses among young children are linked to turbidity levels in drinking water. (Schwartz, J.; Levin, R.; Hodge, K.
Pets monitor indoor air quality. Pets exposed to indoor air environments can be used as surrogate indicators of human exposures to pollutants. (Bukowski, J. A.; Wartenberg, D. "An Alternative Approach for Investigating the Carcinogenicity of Indoor
Health
MAY 1, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 2 3 3 A
