Carbon sequestration. Evidence from studies in nine forests indicates that elevated nitrogen deposition is unlikely to be a major contributor to the sequestration of carbon in tem­perate forests. (Nadelhoffer, K. J.; Emmett, B. A.; Gundersen, P.; Kjonaas, O. J.; Koopmans, C. J.; Schleppi, P.; Tietema, A.; Wright, R. F. "Nitrogen Deposition Makes a Minor Contribution to Carbon Sequestra­tion in Temperate Forests," Nature 1999, 398(6723), 145-148)

Contaminants Plastic contaminant. Results provide an assessment of the leaching of bis-phenol A (used in plastic manufactur­ing as a stabilizer) from plastic waste into water. (Yamamoto, T.; Yasuhara, A. "Quantities of Bisphenol A Leached From Plastic Waste Samples," Chemo-sphere 1999, 38(11), 2569-2576)

Silver. Although silver has been reg­ulated since the 1960s, EPA has downgraded this metal from a pri­mary to a secondary maximum con­taminant level because the exposure effects of silver were judged to be cosmetic. (Purcell, T. W; Peters, J. J. "Historical Impacts of Environmen­tal Regulation of Silver," Environ. Toxicol. Chem. .999, ,8(1), 3-8)

Health Health effects. Human health effects resulting from environmental contam­inants and how these compounds may interact with each other are dis­cussed. (Carpenter, D. O.; Arcaro, K. E; Bush, B.; Niemi, W. D.; Pang, S.; Vakharia, D. D. "Human Health and Chemical Mixtures: An Overview," En­viron. Heallh Perspect. 1998,106(6), 1263-1270)

Methylmercury. Researchers com­pared studies on the health effects of methylmercury at a November work­shop sponsored by the White House Office of Science and Technology Pol­icy and the National Institute of Envi­ronmental Health Sciences and sug­gested testing of additional systems besides neurodevelopmental ones for use in establishing thresholds. ("Meet­ing of the Minds on Mercury," Envi­ron. Health Perspect. 1999,107(1), A12)

Modeling Silver toxicity. Modeling to calculate silver interactions at biological sur­faces is used to illustrate the effects

of water chemistry on silver specia-tion and toxicity to freshwater and marine fish. (Wood, C. M.; Playle, R. C; Hogstrand, C. "Physiology and Modeling of Mechanisms of Silver Uptake and Toxicity in Fish," Envi­ron. Toxicol. Chem. .999, ,8(ll) 711 83)

Approximation methods Analytical chemists are often re­quired to evaluate data quality using limits of detection and quantification methods that are often computation­ally complex. Where feasible, it is desirable to use less rigorous meth­ods. M. E. Zorn and coworkers eval­uated approximate computational methods that use data at multiple spiking concentrations, are iterative, can be derived from either predic­tion intervals or statistical tolerance intervals, and require at a minimum ordinary least-squares regression for calculating the intercept and slope. Results indicate that although exact methods should be employed whenever possible aooroximate methods can provide detection and quantification limits that are suffi-ciently

tions IFnviron ^ri Tprhnol this 2291-229'i)

Remediation Bioremediation potential. During an investigation of bioremediation potential in a gasoline-contaminated aquifer, iron and sulfur species were evaluated along with the aqueous ions of 02, N03_, Fe2+, and S04

2", showing that when mineral data are included, most of the hydrocarbon spill at this site was naturally attenuated. (Kennedy, L. G.; Everett, J. W; Dewers, T; Pickins, W; Ed­wards, D. "Application of Mineral Iron and Sulfide Analysis To Evaluate Natural Attenuation at Fuel-Contam­inated Site " /. Environ. Eng. (Reston Va.) 1999 125(1) 47-56)

Waste treatment. A prototype reac­tor for the Photo-Fenton method was evaluated for processing highly contaminated wastewaters. (Krutzler, T; Bauer, R. "Optimization of a Photo-Fenton Prototype Reactor," Chemosphere 1999, 38(11), 2517-2532)

Sediments Sediment mercury. Watershed area-to-lake area ratio was found to be more important than site-specific fac­tors in governing the concentration of sediment mercury in lakes without industrial input. (French, K. J.; Scru-ton, D. A.; Anderson, M. R.; Schneider, D. C. "Influence of Physical and Chemical Characteristics on Mercury in Aquatic Sediments," Water, Air, Soil Pollut. 1999,110(3-4), 347-362)

Soils Contaminant deposition. The sepa­rated and combined effects of moder­ate levels of acid load and copper-nickel deposition on humus microbial community structures were examined six growing seasons after the start of an artificial irrigation experiment. (Pennanen, T; Perkiomaki, J.; Kiikkila, O.; Vanhala, R; Neuvonen, S.; Fritze, H. "Prolonged, Simulated Acid Rain and Heavy Metal Deposition: Separated and Combined Effects on Forest Soil Microbial Community Structure," FEM) Microbioll Ecol. 1998,27(3) 291-300)

Technology Sensor technology. Barriers are ex­amined that impede development and deployment of novel chemical sensor and biosensor technologies. (Weetall, H. H. "Chemical Sensors and Biosensors Update What, Where, When and How," Biosens. Bioelec-tron. 1999, 14(2), 237-242)

Water Metal-sulfide complexation. New data and calculations confirm the po­tential importance of sulfide as a complexing ligand in seawater, where sulfide is more important than major anions and competes effectively with natural organic ligands. (Al-Farawati, R.; Van den Berg, C.M.G. "Metal-Sulfide Complexation in Seawater," 1999, 63(3-4), 331-352)

Wetlands Assessment techniques. With fur­ther refinement and development, rapid methods of monitoring aquatic community assemblages are poten­tially useful tools for early detection of wetland degradation. (Van Dam, R. A.; Camilleri, C; Finlayson, C. M. "The Potential of Rapid Assessment Techniques as Early Warning Indica­tors of Wetland Degradation: A Re­view," Environ. Toxicol. Water Qual. 1998 i3(4), 297-312)

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