For one engineer in public health service, addressing the BP oil spill cleanup has been anything but business-as-usual for the last few months. Professional engineer John Cardarelli II of Erlanger, Ky., a health physicist with the U.S. Environmental Protection Agency, has a lead role on EPA’s national decontamination team in analyzing data gathered through airborne spectral photometric environmental collection technology—better known as ASPECT.
As part of the agency’s response activities, the ASPECT team was deployed to the Gulf of Mexico in late April to provide aerial reconnaissance, imaging, and stand-off chemical detection and quantification. The aircraft used is equipped with several chemical and radiological sensors with imaging capabilities. “Radiological detection capabilities are not being used in this response,” Cardarelli notes, “but the chemical and imagery sensors and have proven to be extremely powerful.”
The aircraft’s passive remote infrared spectral sensors monitor the downwind hazard of chemicals created during open-water oil burns. These infrared sensors detect and track vapor plumes using two different spectral systems. The first sensor is a multispectral high-spatial-resolution infrared imager that provides two-dimensional images. Visible high-resolution images are also collected and geo-corrected to provide an overlay of the infrared image, the chemical plume, and a visible image of the site. The second infrared instrument, a Fourier transform infrared spectrometer, collects a higher spectral resolution of the infrared signature from a specific plume location and then identifies and quantifies the chemical constituents in the plume.
“We have not seen any significant chemical compounds in the open-water oil burns to date that pose any public health threat to those on shore,” Cardarelli reports. “This is primarily due to what appears to be a fairly efficient burn of the oil, and the fact that these burns occur more than 40 miles from shore. The black plume is predominately elemental carbon that is effectively dispersed before reaching shore.”
Cardarelli explains that infrared spectral imaging differs from visual photography, in that it eliminates glare and glint associated with the visual spectrum and discriminates oil from black water and other areas that appear to be contaminated but actually are not. “This helps decision-makers send ground and water-based assets to facilitate cleanup operations in locations with known oil contamination and reduces or prevents unnecessary deployments to uncontaminated areas,” he adds.
As of late June, the ASPECT team had flown nearly 60 missions, logging 190 flight hours; processed more than 8,700 aerial photos, 5,300 oblique photos, and 2,000 infrared images; and collected more than 2.3 million interferograms.
Currently serving as secretary of NSPE’s Professional Engineers in Government interest group, Cardarelli was lauded as NSPE Federal Engineer of the Year in 2006, the same year he also received Public Health Service Engineer of the Year and EPA Engineer of the Year honors. His professionalism doesn’t stop with the accolades, however. “As engineers, scientists, and researchers, we continuously challenge ourselves to make our products more intuitive with faster delivery times, but we have not spent enough time making others aware of their value to this environmental response,” he emphasizes.
Although Cardarelli admits that the core ASPECT team is small—composed of about four federal employees and six government contractors, including pilots—he says that a concerted effort has been made to increase awareness of newly developed products and their utility to the overall oil spill cleanup activities.
He also contends that his team has “witnessed substantial improvement in the use of these products over time,” and that the unique capabilities of ASPECT to conduct stand-off chemical and radiological detection, combined with imaging and pattern recognition algorithms in a low-altitude environment, make it a valued national asset.
As one might expect, the ASPECT directives have changed throughout the oil spill cleanup process. “At the beginning, we provided situational awareness to the incident command by locating and imaging the oil slicks via aerial reconnaissance,” Cardarelli points out. “We also conducted remote chemical detection during open-water oil burns. After the oil started to reach the beaches, our focus evolved into discriminating between contaminated locations and locations that only appeared to be contaminated.”
The most recent directives, he notes, have been associated with helping to prevent the oil from reaching the beaches by mapping the oil slicks. Those data are delivered within minutes of a sortie, so water-based recovery assets can be immediately deployed to clean up the oil more efficiently.
Looking toward the future, Cardarelli says improved satellite communication from reconnaissance aircraft to the ground base will increase the efficiency of transferring time-critical data. “With proper communications, information can be shared in near real-time rather than waiting for the aircraft to complete its mission” he explains. “This will allow for ground-based assets to better execute their missions.”