Research Watch: Mercury removal

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Modeling Neural networks. Commonly measured fecal bacteria concentrations in water and rainfall data were used as inputs for training a neural network model to distinguish between urban and agricultural fecal contamination present in inputs to a drinking water reservoir. (Brion, G. M.; Lingireddy, S. "A Neural Network to Identifying Nonpoint Sources of Microbial Contamination", Water Res. 1999, 33 (14), 3099-3106) Nitrogen concentrations. An artificial neural network was developed, validated, and tested using 927 nonpoint source watersheds studied for relations between macrodrainage area characteristics and nutrient levels in streams. (Lek, S., et al. "Predicting Stream Nitrogen Concentration From Watershed Features Using Neural Networks", Water Res. 1999, 33 (16), 3469-3478)

Controlling mercury emissions Optimal mercury control technologies are needed for coal-fired power plants, municipal waste combustors, and hospital incinerators, which account for more than 70% of anthropogenic mercury emissions. W. Liu and co-workers performed laboratory experiments to investigate the optimization of high-temperature sulfur impregnation on activated carbon for permanent sequestration of elemental mercury vapors. The fate of spent adsorbents was assessed using a toxicity characteristics leaching procedure (TCLP) Although mercury concentration in all leachates was below the TCLP limit (0 2 mg/L) virgin activated carbon lost a significant fraction of the adsorbed elemental mercury during storage while no loss was observed for sulfur-impregnated carbons Thjo finriing simgests that virgin activated

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Chloromethane degradation. The authors examined the potential for using laboratory-synthesized nanoscale iron particles to transform chloromethanes and achieved rapid transformations of tetrachloromethane and trichloromethane with palladized nanoscale iron particles. (Lien, H.-L.; Zhang, W.-X. "Transformation of Chlorinated Methanes by Nanoscale Iron Particles", /. Environ. Eng. 1999, 125 (11), 1042-1047) Chromate remediation. A small-scale field test was initiated at an old chrome-plating facility to evaluate in situ remediation of groundwater contaminated with chromate using a permeable reactive barrier composed of a mixture of zero-valent Fe, sand, and aquifer sediment. (Puis, R. W.; Paul, C. J.; Powell, R. M. "The Application of In Situ Permeable Reactive (Zero-Valent Iron) Barrier Technology for the Remediation of Chromate-Contaminated Groundwater: A Field Test" Appl. Geochem. 1999 14 (8) 989-1000) Mineral and mine drainage. This review of minerals and mine drainage includes 106 references and describes analytical methods, site as-

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beverages; fruit and vegetables; and solid wastes. (Ross, C. C, et al. "Food Processing Wastes", Water Environ. Res. 1999, 71 (5), 812-816) Mercury removal. The origins and fate of mercury found in hydrocarbon waste are discussed from the perspective of waste minimization, treatment, and disposal (Wilhelm, S. M. "Generation and Disposal of Petroleum Processing Waste That Contains Mercury", Environ. Prog. 1999, 18 (2), 130-143)

Wastewater Disinfection and antimicrobial processes. Ninety-five references are included in this review of disinfection and antimicrobial processes in wastewater treatment, which addresses regulations and policies, health risk, disinfection methods, microbiological and disinfection chemicals, analytical methods, and distribution system regrowth and biofilm. (Kuo, J.-E; Yamashita, L. "Disinfection and Antimicrobial Processes" Water Environ. Res. 1999 71 (5), 685-692)

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sessment, tailings disposal/mine spoil, acid-mine drainage, lotic systems, site rehabilitation, removal technologies, and biological treatment. (Smith, D. P.; Kalch, R. "Minerals and Mine Drainage", Water Environ. Res. 1999, 71 (5), 822-828)

Soil TNT-contaminated soil. The fate of 2,4,6-trinitrotoluene (TNT) and its reduction products was analyzed using a TNT-contaminated soil spiked with [14C]TNT. (Achtnich, C , et al. "Irreversible Binding of Biologically Reduced 2,4,6-trinitrotoluene to Soil", Environ. Toxicol. Chem. 1999, 18 (11), 2416-2423)

Waste Food processing wastes. This review, which contains 58 references on food processing wastes, discusses such topics as dairy; sugar and confectionery; meat, poultry, and seafood; grains;

9 2 A • FEBRUARY 1, 2000 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS

Water Pathogens in water. This review presents 227 references concerning the detection and occurrence of indicator organisms and pathogens in water and wastewater and discusses such topics as microorganism detection, indicator organisms, bacterial pathogens and emerging pathogens, viruses, protozoa, and helminths and other parasites. (Baker, K. H.; Herson, D. S. "Detection and Occurrence of Indicator Organisms and Pathogens" Water Environ. Res. 1999 71 (5) 530-551) Stormwater sampling. The results of this study strongly suggest that discrete sampling of stormwater outfalls is insufficient to characterize the concentrations and distributions of persistent hydrophobic contaminants. (Wenning, R. J., et al. "Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans in Stormwater Outfalls Adjacent to Urban Areas and Petroleum Refineries in San Francisco Bay, California" Arch. Environ. Contam. Toxicol. 1999 37 (3) 290-302)