Impact/Purpose:

To develop an analytical method for monitoring RDX and other explosives in drinking water, which will be suitable for use by OGWDW to collect nationwide occurrence data under the UCMR. Ideally, the method should be simple and rugged enough to be applicable to compliance monitoring in the event that RDX becomes a regulated contaminant under the Safe Drinking Water Act (SDWA). The method should be sensitive enough to provide accurate and precise data below 2 Fg/L.

Description:

RDX is an explosive that is commonly found in and around military installations. RDX can contaminate groundwater, creating the potential for it to occur in drinking water. RDX was listed as a contaminant on the 1998 Contaminant Candidate List (CCL). The CCL lists potential drinking water contaminants that EPA is evaluating for possible regulation under the Safe Drinking Water Act. In order to make a regulatory determination on RDX, EPA must have reliable nationwide occurrence data for RDX in drinking water. Under this task, one or more analytical methods will be developed for the determination of RDX in drinking water. The method(s) will be used by the Office of Ground Water and Drinking Water to gather occurrence data for RDX under its Unregulated Contaminant Monitoring Rule (UCMR). The occurrence data obtained will support EPA's regulatory determination process. The lifetime health advisory concentration for RDX in drinking water is 2 Fg/L. In addition, there is some indication that RDX may be a carcinogen, with an estimated lifetime cancer risk of 1 in 100,000 associated with a drinking water concentration of 3 Fg/L.

Current literature references indicate that immunoassay and biosensor techniques as well as gas chromatography (GC) and high performance liquid chromatography (HPLC) have been used in analytical methods to measure RDX in ground water matrices. Immunoassay techniques are relatively insensitive and subject to false positive results due to cross reactivity with chemicals similar in structure to RDX. These characteristics make these methods unsuitable for UCMR monitoring. Existing GC and HPLC methods require two chromatographic columns to separate and measure common explosive contaminants, and they use non-specific detectors which increases the potential for false positive results. A method based on solid phase extraction followed by GC/MS analysis will be the initial approach for this project, because this approach is expected to provide the sensitivity and selectivity needed for occurrence monitoring. A final method will be delivered to OGWDW by Sept. 2002.

Record Details:

Record Type:PROJECT

Start Date:07/01/2000

Completion Date:09/30/2002

Record ID: 18334

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Project Information:

Progress :Research under this task is complete. Method 529 (Determination of Explosives and Related Compounds in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry) was developed, peer reviewed, and delivered to the Office of Ground Water and Drinking Water in Sept., 2002. This method can be used to analyze for RDX (which is listed on the CCL) and 13 additional explosives and related chemicals in drinking water samples, with detection limits less than 0.1 ug/L for each chemical. This method is an improvement over other published methods in the following ways: (1) use of the mass spectrometer as the detector provides positive identification of all method analytes without the use of additional confirmatory techniques, (2) additional QC procedures such as the use of internal standards and surrogates help to ensure the quality of the data, and (3) the sample preservation protocol ensures sample stability between the time of sample collection and analysis. These improvements will significantly enhance the use of this methodology in the nationwide collection of occurrence data to support regulatory decision making for chemicals on the CCL. It is expected that this method will be proposed for collecting occurrence data in the next Unregulated Contaminated Monitoring Rule (proposal date currently expected for the fall of 2004).

Completed products:

Munch, J.W., Analysis of RDX and other explosives by solid phase extraction and GC/MS. Presented at American Water Works Water Quality Technology Conference, Nashville, TN, November 11-15, 2001.

Munch, J.W., Method 529 - Determination of Explosives and Related Compounds in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry, September, 2002.

Relevance :As a chemical listed on the 1998 CCL, RDX is being evaluated for possible regulation in drinking water. As part of the regulatory determination process, OGWDW must acquire nationwide occurrence data for RDX in drinking water. The analytical method developed under this task is needed by the OGWDW to use in the collection of this occurrence data under the UCMR. It is likely that this method would also be promulgated for compliance monitoring for RDX in the event that it becomes a regulated contaminant under the SDWA. The success of this method development task will result in better monitoring for RDX in drinking water. Better monitoring data will assist OGWDW in better regulatory decisions, and help safeguard the American public from harmful drinking water contaminants.

On-going contact has been established with OGWDW to communicate current method development progress and future requirements. OGWDW currently expects another round of unregulated contaminant monitoring no sooner than FY05, and this method should be ready well before that time frame. In addition, OGWDW's Technical Support Center has agreed to perform a second laboratory validation of the method after its completion. Other contacts that have been established include researchers at the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory. The PI presented the research results to date to the regulated community at the American Water Works Association Water Quality Technology Conference, Nov., 2001.

Clients :Office of Ground Water and Drinking Water (Karen Wirth, Dave Munch)

Research Component :CCL (CHEMICAL)

Risk Paradigm :EXPOSURE

Project IDs:

ID Code :none

Project type :ORD-DW Plan

ID Code :7003

Project type :OMIS