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Oil on the water surface represents just the American Petroleum Institute API > 10 gravity component of any crude oil spill or well blowout, and is identified and tracked by conventional remote sensing means. However, the API ≤ 10 components of the hydrocarbons are not readily accessible by these means. UV sensors on underwater vehicles can sample just a few cubic centimeters at a time and are subject to fouling. Side-scan sonar, under certain conditions, can “see” gas bubbles on the near outer shell of a subsurface plume if they exist early on during a blowout, but cannot assess the entire volume. Oil sequestered in bed sediments in oceans or rivers is not visible to UV sensors, nor is it visible to divers. It is apparent that this sensing gap problem needed to be addressed. A new technology developed by the US Geological Survey, working closely with Williamson & Associates of Seattle, holds promise for rapid mapping and characterization of below-surface hydrocarbons. Crude oil drifting in the deep ocean water column, oil blanketing the seafloor, and oil sequestered in seafloor and river bottom sediments can now be quickly mapped in 3D. If drifting in the seawater column, dispersed oil can be tracked as its distribution evolves over time. This technology also is potentially useful for mapping combined storm-water overflow (CSO, or sewage) deposits, as well as Superfund sites in Puget Sound and other sensitive rivers, bays, and estuaries close to cities that pose serious hazards to both humans and wildlife. The technology is based on a surface-sensitive electro-physical property known as induced polarization (IP). This surface-sensitivity means that highly dispersed IP-reactive materials have more surface area exposed to surrounding water, and are thus more responsive than undispersed materials of the same mass. IP technology has been used successfully for many decades to map disseminated porphyry sulfide deposits on land, but has only been applied commercially at sea since 2007. Recent laboratory and Puget Sound experiments have verified that the IP response of oil dispersed in water and sequestered in sediments is unusually strong: at least 20 times greater than a strong “hit” in an IP survey for sulfide minerals on land. The marine IP system has been towed behind a small boat in as little as 1–2 meters water depth, while one version has been tested (using a towed sled) to 3,500 meters depth. Depending on the cable-streamer design, the depth of detection of chargeable materials in sediments can be greater than 20 meters. It can be used to monitor active drill platforms for leaks. Finally, IP is also strongly reactive to buried pipelines; in the Gulf of Mexico there are over 43,000 miles of poorly-located, often hidden, corroding pipe. We can now map it precisely.

Microorganisms can be transmitted from infected to healthy people as an aerosol. Military bioaerosol detectors currently used by soldiers or first responders may potentially be utilized in health care settings as part of a strategy to prevent the spread of airborne infectious diseases. The goal of this study was to conduct initial laboratory and field validation of an inexpensive and unobtrusive TACBIO detector and compare its performance with that of an expensive bioaerosol detection instrument, the Ultraviolet Aerodynamic Particle Sizer (UV-APS). The laboratory validation test used three bacterial clusters (Bacillus thuringiensis [Bt], Bacillus anthracis Sterne [BaS], and Bacillus atrophaeus var. globigii [Bg]) generated at controlled rates by an ink jet aerosol generator (IJAG). The detection efficiency of the UV-APS was ≥ 99% for all particle generation rates and species. The TACBIO detector exhibited a slightly lower detection efficiency but was still able to detect > 88% of Bt and BaS and 62.7-81.7% of Bg. Field validation conducted with simultaneous UV-APS and TACBIO sampling in an occupied hospital clinic showed both instruments closely tracking each other in detecting fluorescent particles > 1.5 µm in diameter. During a 6 hour sampling period, fluorescent particle (> 1.5 µm) concentrations showed wide short term variation connected to nearby human activity while smaller nonfluorescent particles displayed more gradual changes. These results indicate the usefulness of an unobtrusive environmental aerosol sampler in health care settings, motivating future field characterization and validation studies.

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