A single-channel chip-based analytical microsystem that allows rapid flow injection measurements of the total content of organic explosive or nerve agent compounds, as well as detailed micellar chromatographic identification of the individual ones, is described. The protocol involves repetitive rapid flow injection (screening) assayssto provide a timely warning and alarmsand switching to the separation (fingerprint identification) mode only when harmful compounds are detected. While micellar electrokinetic chromatography, in the presence of sodium dodecyl sulfate (SDS), is used for separating the neutral nitroaromatic explosive and nerve agent compounds, an operation without SDS leads to high-speed measurements of the "total" explosives or nerve agent content. Switching between the "flow injection" and "separation" modes is accomplished by rapidly exchanging the SDS-free and SDS-containing buffers in the separation channel. Amperometric detection was used for monitoring the separation. Key factors influencing the sample throughput, resolution, and sensitivity have been assessed and optimized. Assays rates of about 360 and 30/h can thus be realized for the "total" screening and "individual" measurements, respectively. Ultimately, such development will lead to the creation of a field-deployable microanalyzer and will enable transporting the forensic laboratory to the sample source.

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Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1 percent to 3 percent free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2 percent in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important part of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.

This report presents the results of ventilation rate studies of eight passively ventilated high-level radioactive waste tanks using tracer gases. Headspace ventilation rates were determined for Tanks A-101, AX-102, AX-103, BY-105, C-107, S-102, U-1 03, and U-105 using sulfur hexafluoride (SF,) and/or helium (He) as tracer gases. Passive ventilation rates are needed for the resolution of several key safety issues. These safety issues are associated with the rates of flammable gas production and ventilation, the rates at which organic salt-nitrate salt mixtures dry out, and the estimation of organic solvent waste surface areas. This tracer gas study involves injecting a tracer gas into the tank headspace and measuring its concentration at different times to establish the rate at which the tracer is removed by ventilation. Tracer gas injection and sample collection were performed by SGN Eurisys Service Corporation and/or Lockheed Martin Hanford Corporation, Characterization Project Operations. Headspace samples were analyzed for He and SF, by Pacific Northwest National Laboratory (PNNL). The tracer gas method was first demonstrated on Tank S-102. Tests were conducted on Tank S-102 to verify that the tracer gas was uniformly distributed throughout the tank headspace before baseline samples were collected, and that mixing was sufficiently vigorous to maintain an approximately uniform distribution of tracer gas in the headspace during the course of the study. Headspace samples, collected from a location about 4 m away from the injection point and 15,30, and 60 minutes after the injection of He and SF,, indicated that both tracer gases were rapidly mixed. The samples were found to have the same concentration of tracer gases after 1 hour as after 24 hours, suggesting that mixing of the tracer gas was essentially complete within 1 hour. Given this evidence for vigorous mixing, inhomogeneities produced by the influx of fresh air during normal ventilation would be expected to be restricted to a small region near the influx.

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