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Carton G.,CALIBRE Systems Inc. | Shjegstad S.,Environet Inc. | Edwards M.,University of Hawaii at Manoa | King J.C.,U.S. Army
Pollution Engineering | Year: 2014

The Hawaii Undersea Military Munitions Assessment (HUMMA) is a multi-phase program addressing the challenge of characterizing a historic deep-water munitions disposal site. The Army initiated HUMMA in 2006 to investigate a Department of Defense military munitions sea-disposal site in Hawaii. This poorly documented site is 3 to 20 miles south of Oahu in water depths of 800 to 2,000 feet. The site contains conventional and chemical military munitions, including 16,000 100-pound mustard-filled bombs. HUMMA's approach allows the site to be studied across a broad range of resolutions, stretching from regional maps covering hundreds of square miles to extremely high-resolution imagery of individual munitions and the animals coexisting with them. This approach and its resulting robust, multi-disciplinary dataset will aid in optimizing sampling at other sea-disposal sites in both deep and shallow water. The manned submersibles collected 94 sediment and 30 water samples within 6 feet of high-interest munitions and control sites to evaluate whether munitions constituents, including chemical agents or agent breakdown products, were detectable at levels higher than at nearby munitions-free control sites. One aspect of the program worthy of special mention was the safety precautions related to possible contact with chemical agent. The Army worked closely with the researchers during the planning stages to outline the onboard safety procedures to be followed. Source

Briggs C.,Environet Inc. | Shjegstad S.M.,Environet Inc. | Silva J.A.K.,Environet Inc. | Edwards M.H.,University of Hawaii at Manoa
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2015

There is a strong need to understand the behavior of chemical warfare agent (CWA) at underwater discarded military munitions (DMM) sites to determine the potential threat to human health or the environment, yet few studies have been conducted at sites in excess of 250. m, the depth at which most U.S. chemical munitions were disposed. As part of the Hawai'i Undersea Military Munitions Assessment (HUMMA), sediments adjacent to chemical and conventional DMM at depths of 400-650. m were sampled using human occupied vehicles (HOVs) in order to quantify the distribution of CWA, energetics, and select metals. Sites in the same general area, with no munitions within 50. m in any direction were sampled as a control. Sulfur mustard (HD) and its degradation product 1,4-dithiane were detected at each CWA DMM site, as well as a single sample with the HD degradation product 1,4-thioxane. An energetic compound was detected in sediment to a limited extent at one CWA DMM site. Metals common in munitions casings (i.e., Fe, Cu, and Pb) showed similar trends at the regional and site-wide scales, likely reflecting changes in marine sediment deposition and composition. This study shows HD and its degradation products can persist in the deep-marine environment for decades following munitions disposal. © 2015. Source

Ray C.,University of Hawaii at Manoa | Zheng W.,University of Hawaii at Manoa | Zheng W.,Environet Inc. | D'Alessio M.,University of Hawaii at Manoa | And 3 more authors.
NATO Science for Peace and Security Series C: Environmental Security | Year: 2011

Riverbank filtration (RBF) is a low-cost and efficient water treatment technology for the removal of many surface water pollutants. It is widely used by water utilities in developed as well as developing countries to produce drinking water from surface water which is often polluted. In this research, the presence of explosive chemicals in riverbed sediments or in flowing water is considered as a potential threat to the quality of filtrate produced from RBF systems. For this, degradation experiments were conducted to examine the persistence of these compounds in river sediments. In addition, a model RBF system was setup to examine the breakthrough of the major explosive chemicals and their metabolites. Results show that HMX was the most mobile and compound followed by RDX. TNT and DNT degraded quickly. Thus, the presence of RDX and HMX could produce breakthroughs in high capacity collector wells located along riverbanks. © Springer Science+Business Media B.V. 2011. Source

Payne Z.M.,Environet Inc. | Lamichhane K.M.,University of Hawaii at Manoa | Babcock R.W.,University of Hawaii at Manoa | Turnbull S.J.,U.S. Army
Environmental Sciences: Processes and Impacts | Year: 2013

A nine-month in situ bioremediation study was conducted in Makua Military Reservation (MMR) in Oahu, Hawaii (USA) to evaluate the potential of molasses to enhance biodegradation of royal demolition explosive (RDX) and high-melting explosive (HMX) contaminated soil below the root zone. MMR has been in operation since the 1940's resulting in subsurface contamination that in some locations exceeds USEPA preliminary remediation goals for these chemicals. A molasses-water mixture (1=:=40 dilution) was applied to a treatment plot and clean water was applied to a control plot via seven flood irrigation events. Pore water samples were collected from 12 lysimeters installed at different depths in 3 boreholes in each test plot. The difference in mean concentrations of RDX in pore water samples from the two test plots was very highly significant (p < 0.001). The concentrations differences with depth were also very highly significant (p < 0.001) and degradation was greatly enhanced at depths from 5 to 13.5 ft. biodegradation was modeled as first order and the rate constant was 0.063 per day at 5 ft and decreased to 0.023 per day at 11 ft to 13.5 ft depth. Enhanced biodegradation of HMX was also observed in molasses treated plot samples but only at a depth of 5 ft. The difference in mean TOC concentration (surrogate for molasses) was highly significant with depth (p = 0.003) and very highly significant with treatment (p < 0.001). Mean total nitrogen concentrations also differed significantly with treatment (p < 0.001) and depth (p = 0.059). The molasses water mixture had a similar infiltration rate to that of plain water (average 4.12 ft per day) and reached the deepest sensor (31 ft) within 5 days of application. Most of the molasses was consumed by soil microorganisms by about 13.5 feet below ground surface and treatment of deeper depths may require greater molasses concentrations and/or more frequent flood irrigation. Use of the bioremediation method described herein could allow the sustainable use of live fire training ranges by enhancing biodegradation of explosives in situ and preventing them from migrating to through the vadose zone to underlying ground water and off-site. © 2013 The Royal Society of Chemistry. Source

Silva J.A.K.,Environet Inc. | Chock T.,Environet Inc.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2016

An evaluation of the current condition of sea-disposed military munitions observed during the 2009 Hawaii Undersea Military Munitions Assessment Project investigation is presented. The 69 km2 study area is located south of Pearl Harbor, Oahu, Hawaii, and is positioned within a former deep-sea disposal area designated as Hawaii-05 or HI-05 by the United States Department of Defense. HI-05 is known to contain both conventional and chemical munitions that were sea-disposed between 1920 and 1951. Digital images and video reconnaissance logs collected during six remotely operated vehicle and 16 human-occupied vehicle surveys were used to classify the integrity and state of corrosion of the 1842 discarded military munitions (DMM) objects encountered. Of these, 5% (or 90 individual DMM objects) were found to exhibit a mild-moderate degree of corrosion. The majority (66% or 1222 DMM objects) were observed to be significantly corroded, but visually intact on the seafloor. The remaining 29% of DMM encountered were found to be severely corroded and breached, with their contents exposed. Chemical munitions were not identified during the 2009 investigation. In general, identified munitions known to have been constructed with thicker casings were better preserved. Unusual corrosion features were also observed, including what are termed here as 'corrosion skirts' that resembled the flow and cementation of corrosion products at and away from the base of many munitions, and 'corrosion pedestal' features resembling a combination of cemented corrosion products and seafloor sediments that were observed to be supporting munitions above the surface of the seafloor. The origin of these corrosion features could not be determined due to the lack of physical samples collected. However, a microbial-mediated formation hypothesis is presented, based on visual analysis, which can serve as a testable model for future field programs. © 2015 Elsevier Ltd. Source

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