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Comparison of Pumped and Diffusion Sampling Methods to Monitor Concentrations of Perchlorate and Explosive Compounds in Ground Water, Camp Edwards, Cape Cod, Massachusetts, 2004–05

By Denis R. LeBlanc and Don A. Vroblesky

Toxic Substances Hydrology Program

Prepared in cooperation with the
U.S. Army Environmental Command

This report is available as a printed product and in PDF Format (1.63 MB)

Abstract

Laboratory and field tests were conducted at Camp Edwards on the Massachusetts Military Reservation on Cape Cod to examine the utility of passive diffusion sampling for long-term monitoring of concentrations of perchlorate and explosive compounds in ground water. The diffusion samplers were constructed of 1-inch-diameter rigid, porous polyethylene tubing. The results of laboratory tests in which diffusion samplers were submerged in containers filled with ground water containing perchlorate, RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) indicate that concentrations inside the diffusion samplers equilibrated with concentrations in the containers within the 19-day-long test period. Field tests of the diffusion samplers were conducted in 15 wells constructed of 2- or 2.5-inch-diameter polyvinyl chloride pipe with 10-foot-long slotted screens. Concentrations of perchlorate, RDX, and HMX in the diffusion samplers placed in the wells for 42 to 52 days were compared to concentrations in samples collected by low-flow pumped sampling from 53 days before to 109 days after retrieval of the diffusion samples. The results of the field tests indicate generally good agreement between the pumped and diffusion samples for concentrations of perchlorate, RDX, and HMX. The concentration differences indicate no systematic bias related to contaminant type or concentration levels.

Contents

Abstract

Introduction

Purpose and Scope

Site Description

Study Design

Monitoring-Well Construction and Selection

Pumped Sampling Method

Diffusion Sampling Method

Sample Preservation and Laboratory Analysis Methods

Laboratory Test of Diffusion Samplers

Comparison of Pumped and Diffusion Sampling Methods

Results of Laboratory Test of Diffusion Samplers

Pumped and Diffusion Samples from the Monitoring Wells

Factors Affecting Agreement Between the Methods

Limitations of Study and Suggestions for Future Investigations

Summary

Acknowledgments

References Cited

Figures

1. Map showing location of monitoring wells, water table, plumes of ground-water contamination, and the Impact Area at Camp Edwards on the Massachusetts Military Reservation, Cape Cod, Massachusetts

2–3. Photographs showing—

2. Diffusion sampler showing rigid, porous polyethylene tubing and slip-on end caps with valves

3. Vertical arrangement of diffusion samplers as they are retrieved from a well

4–6. Graphs showing—

4. Comparison of (A) perchlorate, (B) RDX, and (C) HMX concentrations for

5. Comparison of perchlorate, RDX, and HMX concentrations for pumped and diffusion samples collected from selected wells near the Impact Area at Camp Edwards on the Massachusetts Military Reservation, Cape Cod, Massachusetts, 2005

6. Time history of (A) perchlorate, (B) RDX, and (C) HMX concentrations for pumped and diffusion samples collected from monitoring well MW-165M2 at Camp Edwards on the Massachusetts Military Reservation, Cape Cod, Massachusetts, August 2003 to August 2007

Tables

1. Characteristics of monitoring wells used for collection of pumped and diffusion samples at Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts

2. Ordnance-related compounds analyzed in pumped and diffusion samples collected from monitoring wells at Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts, 2004–05

3. Concentrations of perchlorate and explosive compounds in samples from rigid, porous polyethylene diffusion samplers set in carboys containing ground water collected from wells at Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts, May 2004

4. Installation and collection specifications and concentrations of perchlorate, RDX, HMX, and other explosive compounds in diffusion and pumped samples collected from monitoring wells at Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts, November 2004–August 2005

Suggested citation:
LeBlanc, D.R., and Vroblesky, D.A., 2008, Comparison of pumped and diffusion sampling methods to monitor concentrations of perchlorate and explosive compounds in ground water, Camp Edwards, Cape Cod, Massachusetts, 2004–05: U.S. Geological Survey Scientific Investigations Report 2008–5109, 16 p.

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