RESEARCH WATCH Air Polycyclic aromatic hydrocarbons. Source characterization techniques for accumulated and ambient particulates are presented, with polycyclic aromatic hydrocarbon profiles and physical form used in qualitative and quantitative source apportionment estimations. (Oda, J.; Maeda, I.; Mori, T.; Yasuhara, A.; Saito, Y. "The Relative Proportions of Polycyclic Aromatic Hydrocarbons and Oxygenated Derivatives in Accumulated Organic Particulates as Affected by Air Pollution Sources," Environ. Technol. 1998, 29(10), 961-976)
Climate Change Carbon storage variations. A transient process-based biogeochemistry model of terrestrial ecosystems is used to investigate interannual variations of carbon storage in undisturbed Amazonian ecosystems in response to climate variability and increasing atmospheric carbon dioxide concentrations from 1980 to 1994. (Tian, H.; Melillo, J. M.; Kicklighter, D. W.; McGuire, A. D.; Helfrich, J.V.K., III; Moore, B„ III; Vorosmarty, C. J. "Effect of Interannual Climate Variability on Carbon Storage in Amazonian Ecosystems," Nature (London) 1998, 396(6712), 664-667) Last deglaciation. Climatic forcing acted in the same manner in both the North Atlantic seaboard and in central North America during the last deglaciation, with atmospheric circulation playing an important role in the propagation of these events. (Yu, Z.; Eicher, U. "Abrupt Climate Oscillations During the Last Deglaciation in Central North America," Can. Sci. (Washington, D.C.) 1998, 282(5397), 2235-2238)
Modeling Marine aerosol production. To improve the knowledge of matter exchange and pollutant recycling from
Toxic compound detection Generally applicable, real-time detection methods are needed for monitoring low-level emissions of toxic compounds. R. Vasudev and coworkers evaluated application of cavity ring-down spectroscopy (CRDS) to understand if it provides the necessary characteristics for accomplishing this objective. Their CRDS study of nitrogen dioxide and four chlorinated aromatic volatile organic compounds demonstrates that partsper-million detection limits are achievable and that with experimental improvements to enhance technique sensitivity, detection within the parts-per-billion range is feasible. Detection sensitivity was independent of the degree of or site of chlorination, and the method is self-calibrating. The authors suggest that CRDS promises to be universally applicable for toxic gas detection. (Environ. Sci. Technol., this issue, pp. 1936-1939!
the sea surface into the atmosphere, a spray drop adsorption model was developed and validated. (Oppo, C ; Bellandi, S.; Degli, I. N.; Stortini, A. M.; Loglio, G.; Schiavuta, E.; Cini, R. "Surfactant Components of Marine Organic Matter as Agents for Biogeochemical Fractionation and Pollutant Transport via Marine Aerosols," Mar. Chem. 1999, 63(3-4), 235-253)
Pollution Prevention Membrane separation processes. As an environmentally friendly alternative to conventional separation processes, membrane separation techniques are suitable for mixtures of liquids, gases, and vapors. (Paul, D.; Ohlrogge, K. "Membrane Separation Processes for Clean Production," Environ. Prog. 1998, 27(3), 137-141)
Technology Water treatment. Technologies and tests that enable monitoring of sewage and water treatment works intakes for either identifying and applying consent limits on pollution sources or automatic switching to enhanced treatment processes or diversion mechanisms to prevent disruption are discussed. (Fearnside, D.; Caffoor, I. "The Detection of Pollution: Some Novel Approaches," Environ. Toxicol. Water Qual. 1998, 23(4), 347-357)
Toxicity Silver compounds. In soil, sewage sludge, and sediments where silver sulfide predominates, the toxicity of silver, even at high total concentrations, is very low. (Ratte, H. T. "Bioaccumulation and Toxicity of Silver Compounds: A Review," Environ. Toxicol. Chem. 1999, 28(1), 89-108)
Sediments
Water Quality
Biodegradation processes. The relation of aerobic and anaerobic biodegradation on the ecotoxicity of the priority organic pollutants nonylphenol and aniline is examined. (Dutka, B. J.; Liu, D.; lurkovic, A.; Mclnnis, R.; Lee, H-B.; Onuska, E; Rao, S. S. "Observations From a SixMonth Study on the Effect of Biodegradation Processes in Sediment on the Toxicity Potential of Targeted Chemicals," Environ. Toxicol. Water Qual. 1998, 23(4), 313-322)
Nutrients. Environmental settings such as land use, surficial geology, and soil drainage characteristics can explain variations in the concentration of certain sediment and nutrient constituents. (McMahon, G.; Harned, D. A. "Effect of Environmental Settings on Sediment, Nitrogen, and Phosphorus Concentrations in Albemarle-Pamlico Drainage Basin, North Carolina and Virginia, USA," Environ. Management 1998, 22(6), 887-903)
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