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Ordnance Reef Remedial Investigation

Ordnance Reef Remedial Investigation

Project Highlights:

Project Description:

In 2006, the United States Departments of the Army and the Navy funded a survey of Site HI-06 off of O’ahu, Hawai’i, locally known as Ordnance Reef, an area of shallow fringing near-shore reef that was used as a disposal area for discarded military munitions following World War II. This study determined site boundaries, the quantity, type, and locations of munitions present, collected and analyzed sediment and fish samples, and generated a screening level survey of the data suggesting that contamination from munitions did not pose a threat to human health. Subsequent review of the 2006 study by community members as well as state and Federal resource agencies identified several data gaps requiring further investigation. The USACE Pacific Ocean Division identified remaining study questions and engaged local experts to design and conduct the follow-on investigation. Environet assisted UH in conducting a remedial investigation and risk assessment of Ordnance Reef. The National Oceanic and Atmospheric Administration also contributed to the ongoing research effort by deploying sensors that will monitor ocean currents in the area.

The Ordnance Reef Remedial Investigation, awarded by USACE to the UH Applied Research Laboratory, has been designed to fill gaps identified in the prior investigation and address the potential impact of seasonal variations on conditions at Ordnance Reef. As part of the investigation, samples of sediment, seawater, and human food item biota were collected from Ordnance Reef and shipped to mainland laboratories to be analyzed for chemicals of concern including energetics and metals. Sample locations were prioritized based on a hierarchy of decreasing level of anticipated risk to human receptors prior to any sampling taking place. In order to separate the influence of Discarded Military Munitions (DMM) from other potential sources of contamination, samples were collected from nearby areas subject to wastewater treatment plant (WWTP) effluent, non-point source (NPS) pollution discharge, and from a relatively undisturbed (control) area. Samples were collected during two seasons of the year to evaluate differences that may be caused by variations in rainfall or wave regime during the summers and winters. This project has also involved working with a commercial analytical laboratory, with guidance and input from the Ordnance Reef Coordinating Council, to refine the standard suite of analytical tests typically used to look for energetics compounds so that they are applicable to Hawaiian biota species.

The first Ordnance Reef contract is complete, and has resulted in the generation of a comprehensive data set of sample results, a GIS database of sample locations in proximity to munitions objects, and a series of technical memos and presentations to the community and applicable resource agencies summarizing the work progress to date. Development of the Remedial Investigation report, including a human health risk assessment and an ecological risk assessment, is ongoing under a separate follow-on contract.

Environet has also been tasked with assisting UH in collecting additional samples from Ordnance Reef following the Army’s largest 2011 technology demonstration; during which a remotely operated underwater munitions recovery system was used to remove select munitions from the area. Environet’s role will be to assist UH in assessing any impacts to the environment as a result of the removal action.

Cooperation and Responsiveness
This extremely high-profile project has required a concerted effort to satisfy multiple stakeholders including the USEPA, State of Hawaii DOH, State of Hawaii DLNR, and the community along the Leeward Coast. To date, all issues raised by the resource agencies and the community have been successfully navigated.