Objective:

Perchlorate-contaminated groundwater is an issue of great national concern. Perchlorate has now been detected in groundwater or drinking water in 35 states. In the past, it was assumed that historical use and disposal practices by the military and military contractors, perchlorate manufacturers, and several commercial industries were the sole contributors of perchlorate contamination in the environment. However, a number of sites now have been identified for which military or commercial sources of perchlorate contamination are unlikely, including nearly 40,000 square miles in western Texas. Recent studies also suggest that natural sources of perchlorate, including Chilean nitrate fertilizer, evaporate minerals, and atmospheric processes, may add perchlorate to soils and groundwater although the extent to which natural perchlorate contributes to environmental contamination is unknown. The objective of this project is to develop and validate stable isotope methods to distinguish anthropogenic from natural perchlorate in the environment.

Technology Description:

This project represents a collaborative effort among Shaw Environmental, the University of Illinois at Chicago, the U. S. Geological Survey, and Oak Ridge National Laboratory. Stable isotope ratio analysis of chlorine and oxygen in the perchlorate molecule will be employed as the primary forensic tool to identify perchlorate from different sources. This technique initially will be applied to a wide variety of solid perchlorate samples of differing origin to develop a broad database of isotopic signatures among natural and man-made materials. Once this database is established, groundwater samples will be collected from various locations, including known military sites and sites suspected to have natural contamination. Isotopic signatures of perchlorate in these waters then will be determined. These data will be evaluated with other geochemical variables, including iodine and tritium levels, to firmly establish perchlorate origin. Isotopic evaluation of perchlorate found in other environments, including soils, surface water, rainwater, and plant matter, also will be performed for source identification. In addition to forensics, recent data suggests that isotopic analysis is a sensitive technique to document and confirm perchlorate biodegradation during in situ remediation efforts. The utility of this technique for monitoring perchlorate in the field also will be validated in this project.

Expected Benefits:

This project will provide the Department of Defense (DoD) with a scientific assessment of the contribution of natural perchlorate to environmental contamination, a validated forensic technique for distinguishing military from natural perchlorate, and a new method to document perchlorate biodegradation in the field. The results will be valuable in determining DoD's appropriate liability for perchlorate contamination and in verifying perchlorate bioremediation. (Anticipated Project Completion - 2007)

Principal Investigator:
Dr. Paul Hatzinger
Shaw Environmental and Infrastructure, Inc.
Princeton Research Center
17 Princess Road
Lawrenceville, NJ 08648
Telephone: (609) 895-5356
Fax: (609) 936-9221
E-mail: paul.hatzinger@shawgrp.com

DoD Liaison:
Mr. Bryan Harre
Naval Facilities Engineering Service Center
1100 23rd Avenue, Code 413
Port Hueneme, CA 93043
Telephone: (805) 982-1795
Fax: (805) 982-4304
E-mail: bryan.harre@navy.mil