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
Toxicity
Anaerobic benzene oxidation 3+
Biologically mediated benzene oxidation coupled with Fe reduction in petroleumcontaminated aquifers does not occur under most field conditions and, in instances where it does occur, has not been extensively studied. R. Anderson and coworkers identified a site at which rapid benzene oxidation was occurring in situ and traced this to the presence of high numbers of specific microorganisms from the family Geobacteraceae. Results of analysis of [14C]benzene oxidation in undisturbed sediments indicate that anaerobic benzene oxidation may be restricted to narrowly confined portions of the Fe3+ reduction zone. These results suggest that assaying for Fe3+-reducing microorganisms may aid in identifying zones in which anaerobic benzene oxidation occurs. {Environ. Sci. Technol., this issue, pp. 1222-1229)
Air Pollution: Pets As Sentinels of Environmental Cancer Risk," Environ. Health Perspect. 1997,105{11), 1312-1318)
Measurements Quantifying herbicides. A new trace analysis technique for detecting imidazolinone herbicides has been developed. (Lagana, A.; Fago, G.; Marino, A. "Simultaneous Determination of Imidazolinone Herbicides from Soil and Natural Waters Using Soil Column Extraction and Off-Line Solid-Phase Extraction Followed by Liquid Chromatography with UV Detection or Liquid Chromatography/ Electrospray Mass Spectrometry," Anal. Chem. 1998, 70, 121-130)
evolution over the past 70 years and suggests improvements. (Thomann, R. V. "The Future Golden Age of Predictive Models for Surface Water Quality and Ecosystem Management,"/. Environ. Eng. 1998, 124(2), 94-103)
Methyl mercury and sludge. The first quantitative1measurementsof a terrestrial source of methyl mercury to the atmosphere were obtained from a study of soil amended with sewage sludge. (Carpi, A.; Lindberg, S. E.; Prestbo, E. M.; Bloom, N. S. "Methyl Mercury Contamination and Emission to the Atmosphere From Soil Amended with Municipal Sewage Sludge," J. Environ. Qual. 1997, 26, 1650-1655) Tree rings and metal emissions. Concentrations of lead and cadmium in tree rings are used to monitor historic emissions of heavy metals from anthropogenic sources. (Jonsson, A; Eklund, M.; Hakansson, K. "Heavy Metals in the Environment," /. Environ. Qual. 1997, 26, 1638-43)
Modeling Water quality models. An analysis of water quality models indicates their
Waste Dioxinlike compounds. Unidentified dioxinlike compounds in fly ash may account for its unexplained toxicity. (Till, M.; Behnisch, P.; Hagenmaier, H.; Bock, K. W; Schrenk, D. "Dioxinlike Compounds in Incinerator Fly Ash: A Comparison Between Chemical Analysis Data and Results from a Cell Culture Bioassay," Environ. Health Perspect. 1997,105(12), 1326-32)
Pesticides Atrazine sorption in soils. Atrazine sorption in soils is influenced by soil organic carbon, pH, and soil clay content. (Novak, J. M.; Moorman, T. B.; Cambardella, C. A. "Atrazine Sorption at the Field Scale in Relation to Soils and Landscape Position," /. Environ. Qual. 1997, 26, 1271-1277)
Risk Metals
Fuel oil phytotoxicity. Fuel oil hydrocarbon contaminants in soils reduced plant growth, but uptake of hydrocarbons in stems and leaves was not observed. (Chaimneau, C. H.; Morel, J. L.; Oudot, J. "Phytotoxicity and Plant Uptake of Fuel Oil Hydrocarbons," /. Environ. Qual. 1997, 26, 1478-83)
Ecological risk of mercury. Data uncertainties confound assessments of wildlife harm. (Meyer, M. W "Ecological Risk of Mercury in the Environment: The Inadequacy of the Best Available Science," Environ. Toxicol. Chem. 1998, 17, 137-138)
Soils Nitrogen cycling. Soil microbial populations responsible for nitrogen cycling may be more sensitive to adverse effects of contaminants than previously reported. (Fuller, M. E.; Scow, K. M. "Impact of Trichloroethylene and Toluene on Nitrogen Cycling in Soil," Appl. Environ. Microbiol. 1997, 63(10), 4015-4019) Soil ingestion. EPA methodology for estimating soil ingestion risks for children may not be protective. (Calabrese, E. J.; Stanek, E. J.; James, R. C; Roberts, S. M. "Soil Ingestion: A Concern for Acute Toxicity in Children," Environ. Health Perspect. 1997, 105(12), 1354-58)
2 3 4 A • MAY 1, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS
Wastewater Surface water contaminants. Urban wastewater treatment plant effluents are a major contributor to herbicide pollution of surface water. Herbicides, such as diuron, mainly used in urban weed control account for the major effluent load. (Nitschke, L.; Schussler, W. "Surface Water Pollution by Herbicides From Effluents of Waste Water Treatment Plants," Chemosphere 1998, 36(1), 35-41) Monitoring wastewater effluents. A remote-sensing technique is described for monitoring wastewater pond quality. (Gitelson, A.; Stark, R.; Dor, I. "Quantitative Near-Surface Remote Sensing of Wastewater Quality in Oxidation Ponds and Reservoirs: A Case Study of the Naan System," Water Environ. Res. 1997, 69(7), 1263-70)
Contributors: Michael Brauer, University of British Columbia, Vancouver, Canada; Brian Eitzer, Connecticut Agricultural Experiment Station, New Haven, Conn.; Stephen Geiger, Remediation Technologies, Inc., King of Prussia, Pa.; Vincent Hand, Miami University, Institute of Environmental Sciences, Oxford, Ohio; Louis Kovach, Ecolife Associates, Wilmington, Del; Geoffrey Nobes, McGill University, Montreal, Canada; and Raewyn Town, Queen's University of Belfast, Northern Ireland.
