Link to USGS home page

Thumbnail of cover and link to full-size cover

Comparison of Vapor Concentrations of Volatile Organic Compounds with Ground-Water Concentrations of Selected Contaminants in Sediments beneath the Sudbury River, Ashland, Massachusetts, 2000

Open-File Report 02-143

 By Jean P. Campbell, Forest P. Lyford, and Richard E. Willey

ABSTRACT

A mixed plume of contaminants in ground water, including volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), and metals, near the former Nyanza property in Ashland, Massachusetts, discharges to the Sudbury River upstream and downstream of Mill Pond and a former mill raceway. Polyethylene-membrane vapor-diffusion (PVD) samplers were installed in river-bottom sediments to determine if PVD samplers provide an alternative to ground-water sampling from well points for identifying areas of detectable concentrations of contaminants in sediment pore water near the ground-water and surface-water interface. In August and September 2000, the PVD samplers were installed near well points at depths of 8 to 12 inches in both fine and coarse sediments, whereas the well points were installed at depths of 1 to 5 feet in coarse sediments only.

Comparison between vapor and water samples at 29 locations upstream from Mill Pond show that VOC vapor concentrations from PVD samplers in coarse river-bottom sediments are more likely to correspond to ground-water concentrations from well points than PVD samplers installed in fine sediments. Significant correlations based on Kendall's Tau were shown between vapor and ground-water concentrations for trichloroethylene and chlorobenzene for PVD samplers installed in coarse sediments where the fine organic layer that separated the two sampling depths was 1 foot or less in thickness.

VOC concentrations from vapor samples also were compared to VOC, SVOC, and metals concentrations from ground-water samples at 10 well points installed upstream and downstream from Mill Pond, and in the former mill raceway. Chlorobenzene vapor concentrations correlated significantly with ground-water concentrations for 5 VOCs, 2 SVOCs, and 10 metals. Trichloroethylene vapor concentrations did not correlate with any of the other ground-water constituents analyzed at the 10 well points. Chlorobenzene detected by use of PVD samplers appears to be a strong indicator of the presence of VOCs, SVOCs, and metals in ground water sampled from well points at this site.

Results from PVD samplers indicate that contaminant concentrations in water from well points installed 1 to 5 ft below fine sediments may not reflect concentrations in pore water less than 1 foot below the river bottom. There is insufficient information available to determine if VOC concentrations detected in PVD samplers are useful for identifying detectable aqueous concentrations of SVOCs and metals in sediment pore water at this site. Samples of pore water from a similar depth as PVD samplers are needed for confirmation of this objective.

CONTENTS

Abstract

Introduction

Description of Study Area

Study Design

Study Methods

Polyethylene-Membrane Vapor-Diffusion Samplers

Construction of Samplers

Installation and Retrieval of Samplers

Analysis of Vapor Samples

Quality Assurance and Quality Control

Collection and Analysis of Ground-Water Samples

Statistical Methods

Quality-Assurance Results for Vapor Samples

Compounds Detected in Vapor Samples Upstream from Mill Pond

Comparison of Volatile Organic Compounds in Vapor and Ground-Water Samples

Comparison of Chemicals in Vapor and Ground-Water Samples

Assessment of Sampling Methods

Summary and Conclusions

References

FIGURES

1 through 3. Maps showing:

  1. Location of 10 well points near Mill Pond, extent of contaminants in ground water, and direction of ground-water flow, Ashland, Massachusetts
  2. Vapor-diffusion sampler locations and trichloroethylene concentrations from vapor and ground-water samples upstream from Mill Pond
  3. Vapor-diffusion sampler locations and chlorobenzene concentrations from vapor and ground-water samples upstream from Mill Pond
  4. Daily and median daily streamflow for the Sudbury River at Saxonville and rainfall at Worcester, August and September 2000

5 through 10. Graphs showing:

  1. Concentrations of (A) chlorobenzene and (B) trichloroethylene by sediment type in ground-water and vapor samples upstream from Mill Pond
  2. Concentrations of (A) chlorobenzene and (B) trichloroethylene in ground-water and vapor samples near Mill Pond
  3. Cobalt concentration in ground water by chlorobenzene concentration in vapor near Mill Pond
  4. Nickel concentration in ground water by chlorobenzene concentration in vapor near Mill Pond
  5. 1,2-dichlorobenzene concentration in ground water by chlorobenzene concentration in vapor near Mill Pond
  6. Trichloroethylene concentration in ground water by chlorobenzene concentration in vapor near Mill Pond

TABLES

  1. Sampling and installation dates for polyethylene-membrane vapor-diffusion samplers and well points upstream from Mill Pond (first study phase) and at four areas near Mill Pond (second study phase), Ashland, Massachusetts, August­September 2000
  2. Concentration and relative percent difference between field duplicate sample pairs for chlorobenzene and trichloroethylene from vapor samples near Mill Pond
  3. Concentration of selected volatile organic compounds from vapor and ground-water samples at the Sudbury River upstream from Mill Pond
  4. Comparison of ground-water and vapor-sample concentrations for chlorobenzene and trichloroethylene near Mill Pond
  5. Concentration of selected contaminants from ground-water and vapor samples at 10 well points near Mill Pond
  6. Kendall's Tau p-values for selected volatile organic compounds in ground water and vapor compared to selected volatile organic compounds, semi-volatile organic compounds, and metals in ground water at well points near Mill Pond

AVAILABILITY

This report is presented in Portable Document Format (PDF).  

To view and print report you need to use Adobe Acrobat Reader, available as freeware.

Users with visual disabilities can visit this site for conversion tools and information to help make PDF files accessible.

Outside Cover--1 page (21 KB)

Inside Cover--2 pages (43 KB)

Contents--2 pages (62 KB)

Body of Report--33 pages (802 KB)

Whole Report--37 pages (774 KB)




U.S. Department of the Interior, U.S. Geological Survey
Persistent URL:
Page Contact Information: Contact USGS
Last modified: Wednesday, December 07 2016, 07:03:55 PM
FirstGov button  Take Pride in America button