Methods Ammonium compounds. A liquid chromatography-felectrospray ionization) mass spectrometry method for the determination of herbicides diquat and paraquat in water is described. (Taguchi, V Y.; Jenkins, S.W.D.; Crazier, E W.; Wang, D. T. "Determination of Diquat and Paraquat in Water by Liquid Chromatography- (Electrospray Ionization) Mass Spectrometry," /. Am. Soc. Mass Spectrom. 1998, 9, 830-839) Biosensor development. A biosensor using bacteria isolated from activated sludge was developed and used to estimate oxygen demand for effluent from wastewater treatment plants. (An, L.; Mu, H.; Zeng, H. "A New Biosensor for Rapid Oxygen Demand Measurement," Water Environ. Res. 1998, 70(5), 1070-1074) Dissolved gases. A novel method for the detection of dissolved gas species in natural waters is presented. (Capasso, G.; Inguaggiato, S. "A Simple Method for the Determination of Dissolved Gases in Natural Waters," Appl. Geochem. 1998, 13(5), 631-642) Selective PAH extraction. A selective extraction method was developed that uses supercritical carbon dioxide and allows the GC/MS quantitation of nonpolar compounds in the presence of a substantial lipid background. (Ali, M. Y; Cole, R. B. "SFE Plus C 18 Lipid Cleanup Method for Selective Extraction and GC/MS Quantitation of Polycyclic Aromatic Hydrocarbons in Biological Tissues," Anal. Chem. 1998, 70(15), 3242-3248) Sulfonic acid degradates. An LC/ MS/MS analysis method is described that permits qualitative and quantitative trace-level analysis of sulfonic acid degradates of three chloroacetanilide herbicides and one chloroacetamide herbicide in groundwater. (Vargo, J. D. "Determination of Sulfonic Acid Degradates of Chloroacetanilide and Chloroacetamide Herbicides in Groundwater by LC/ MS/MS," Anal. Chem. 1998, 70(13), 2699-2703)
Remediation Organic contaminant sorption. Soils, subsoils, and aquifer materials
Soils Leachate test failure Oxoanion forms of EPA-regulated elements may not be detected by current standard extraction procedures used to assess toxicity of solid waste leachates. K. Hooper and coworkers compared three procedures: the Toxicity Characteristic Leaching Procedure (0.1-M acetate extractant), the Waste Extraction Test (0.2-M citrate), and the Synthetic Precipitation Leaching Procedure (sulfate/ nitrate; simulates rainfall) with actual municipal solid waste leachates. For the oxoanion-forming elements Sb Mo Se V and As none of these procedures adequately predicted the concentrations extractable by solid waste leachates Thus the possibility ari^ps that wastes Hassified as nonhazardnii
