Army Aberdeen Proving Ground Research Articles

Evaluation of Seismic-Acoustic Analysis Methods for a Real-time UXO Monitoring System

The Department of Defense (DoD) uses over two million rounds of high-explosive (HE) munitions per year ( Defense Science Board Task Force, 2003 ). A small percentage does not explode, thus generating unexploded ordnance (UXO) in current range areas at a substantial rate. As these ranges are closed, the DoD becomes responsible for the environmental restoration of the affected properties. Current methods of UXO remediation are costly because of high false alarm rates. Our current research is to develop a complementary technology that will alleviate false alarm rate by detecting, classifying, and locating UXO in near real time (less than 1 minute) as a munition impacts the range. This technology will utilize an array of buried seismic sensors in a calibrated range area, along with a set of algorithms based on theoretical and applied seismology and statistical analysis.Initial field tests at three sites focused on developing concepts of the seismic and acoustic location of ordnance impacts. Our research program developed from these initial field tests has four primary objectives: 1) fully implement a wired seismic-acoustic ordnance impact location system for live fire ranges; 2) develop a system capability to discriminate high-order (HE), low-order (partially exploded), and zero-order (UXO) events; 3) reduce location error to a stringent program metric of 1–2 m; and 4) investigate the feasibility of developing a wireless implementation of the technology.This paper describes the procedures and results from follow-on tests that were conducted in two locations at the U.S. Army Aberdeen Proving Ground (APG), Maryland. These tests were used to evaluate potential seismic-acoustic methods and system configurations for a Seismic-Acoustic Impact Monitoring Assessment (SAIMA) system for mitigating UXO hazards. Significant results from this work include: 1) seismic impulses from low-order impacts were detected at distances up to 1,000 meters; 2) classification features based on measurements of the amplitude of acoustic and seismic phases produce clear discrimination between HE and UXO impacts; 3) calculated location solutions for HE and UXO impacts yield an average location error of 10–20 meters; and 4) empirical observation and waveform modeling demonstrated that surface waves dominate the signal at all distances and therefore should be the primary phase used for all components of analysis. Furthermore, these tests demonstrated the current system design, allowing further enhancements, is capable of meeting the initial research objectives (1) and (2). Future research will focus on improving system performance with refinement of the sensor-layout geometry and the detection and location algorithms through system error analyses and follow-on field testing.

Mustard Agent Leak Under Investigation

In 60 years, no Leaking mustard agent had ever been detected at the Army's Aberdeen Proving Ground (APGl storage area in Mary- Land. That changed when an alarm sounded recently in an igloo holding ton-sized containers of the chemical warfare agent awaiting disposal via neutralization. The trace amount (7.68 ig/m3) of mustard vapor detected by the alarm was confirmed using mini Chemical Agent Monitors that were inserted into the storage igloo, says Jeff Lindblad, spokesman for the Army Chemical Materials Agency. No liquid agent was found. Whatever leaked has not escaped from the storage building, APG spokesman George Mercer says. He adds, Since the original detection, no additional vapor has been detected inside the structure. The storage igloo is located within the Edgewood Area of APG and a few hundred yards from the building where agent neutralization actually takes place. No workers were exposed to the blister agent. After temporarily relocating workers at the neutralization ...

Acute and chronic toxicity of the new explosive CL-20 to the earthworm (Eisenia andrei) exposed to amended natural soils.

Monocyclic nitramine explosives such as 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are toxic to a number of ecological receptors, including earthworms. The polycyclic nitramine CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) is a powerful explosive that may replace RDX and HMX, but its toxicity is not known. In the present study, the lethal and sublethal toxicities of CL-20 to the earthworm (Eisenia andrei) are evaluated. Two natural soils, a natural sandy forest soil (designated RacFor2002) taken in the Montreal area (QC, Canada; 20% organic carbon, pH 7.2) and a Sassafras sandy loam soil (SSL) taken on the property of U.S. Army Aberdeen Proving Ground (Edgewood, MD, USA; 0.33% organic carbon, pH 5.1), were used. Results showed that CL-20 was not lethal at concentrations of 125 mg/kg or less in the RacFor2002 soil but was lethal at concentrations of 90.7 mg/kg or greater in the SSL soil. Effects on the reproduction parameters such as a decrease in the number of juveniles after 56 d of exposure were observed at the initial CL-20 concentration of 1.6 mg/kg or greater in the RacFor2002 soil, compared to 0.2 mg/kg or greater in the SSL soil. Moreover, low concentrations of CL-20 in SSL soil (approximately 0.1 mg/kg; nominal concentration) were found to reduce the fertility of earthworms. Taken together, the present results show that CL-20 is a reproductive toxicant to the earthworm, with lethal effects at higher concentrations. Its toxicity can be decreased in soils favoring CL-20 adsorption (high organic carbon content).

Spatial variability in the soil foodwebs in a contaminated grassland ecosystem

Spatial relationships among soil nematodes and soil microorganisms were investigated in a grassland ecosystem at the U.S. Army's Aberdeen Proving Ground, Maryland. This area was contaminated with a wide range of concentrations of heavy metals. The study quantified microbial biomass, the abundance of soil protozoa and nematode populations. Geostatistical techniques were used to evaluate cross-correlations among biotic and abiotic parameters and to determine spatial distributions of these parameters in soil. The graphical analysis technique displayed a surface in three-dimensional space, the topography of which was generated by an independent variable and the surface colored by a dependent variable. Both the visualization technique and the cross general relative semivariogram showed a negative correlation between the abundance of fungivore nematodes and fungal biomass, the abundance of bacterivore nematodes and bacterial biomass, and between the numbers of protozoa and microbial biomass in less-contaminated portions of the study site. Graphical analyses of the spatial distribution of soil biota showed that relationships among components of the soil foodweb were altered in the highly contaminated area compared to the less-contaminated local background area. This suggests that environmental conditions in the soil of the contaminated areas may have a detrimental effect on trophic interactions in the soil foodweb.

Soil heavy metal concentrations, microbial biomass and enzyme activities in a contaminated grassland ecosystem

Soil enzyme activities and microbial biomass were measured in a grassland ecosystem with a wide range of heavy metal concentrations ranging from 7.2 to 48.1 mmol kg −1 (As, Cd, Cr, Cu, Ni, Pb and Zn) in portions of the U.S. Army's Aberdeen Proving Ground, Maryland, U.S.A. Total and fluorescein diacetate active (FDA) fungal biomass, FDA-active bacterial biomass, substrate-induced respiration (SIR), the activity of N-acetylglucosaminidase, β-glucosidase, endocellulase, and acid and alkaline phosphatases were also measured. Most measures of microbial biomass were lower in polluted soils. Significant reductions (10- to 50-fold) in the activities of all enzymes closely paralleled the increase in heavy metal concentrations. These results demonstrate that heavy metal contamination of soil has adversely affected the abundance and activity of microorganisms involved in organic matter decomposition and nutrient cycling in this site.

The impact of impulsive noise on bald eagles at Aberdeen Proving Ground, Maryland.

The U.S. Army Aberdeen Proving Ground supports one of the largest bald eagle concentrations on the Northern Chesapeake Bay (Buehler et al., 1987). The testing of large caliber weapons and detonation of large explosive charges at U.S. Army Aberdeen Proving Ground is creating significant noise and producing concerns on the potential effects on bald eagles. The population using Aberdeen consists of approximately 15 nesting pairs and up to 100 wintering or nonbreeding residents. Systematic observations on potential influence of noise on bald eagles were made from November 1993 through December 1995. We detected no response in a high percentage of nesting and roosting eagles exposed to numerous types of noise at varying levels of intensity.

New Defenders of Wildlife

ames Bailey stands on the banks of Romney Creek, a broad but short tidal stream that flows through the US Army's Aberdeen Proving Ground and into the Chesapeake Bay north of Baltimore. Here, on a sunny fall day, an eastern deciduous forest sheds its autumn leaves quietly not far from a site where Army engineers test weapons, munitions, and other military equipment. A short distance upstream, some 30-40 roosting bald eagles eye the water for signs of fish. Downstream, great mounds of dried guano on Pooles Island in the Chesapeake Bay attest to the 600 pairs of great blue herons that nested there over the summer. At a nearby pond, some 2000 ducks and other migrating waterfowl rest on cool fall nights. If we weren't here, this land would be all marinas and condominiums, says Bailey, an Army wildlife biologist at Aberdeen. Instead, Aberdeen's 79,000 acres hold a healthy deer herd, beaver ponds, turkey vultures and black vultures, red-tailed and marsh hawks, and the largest bald eagle population on the northern Chesapeake. We are a de facto wildlife sanctuary, Bailey