Estimating contaminant losses from components of remediation alternatives for contaminated sediments

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Introduction

Background

Assessment and Remediation of Contaminated Sediments (ARCS) Program

Industrial and municipal point-source discharges and nonpoint source pollution from agricultural and urban areas over many years have contaminated bottom sediments in the rivers, harbors, and nearshore areas of the Great Lakes. Improved controls for discharges have reduced pollutant loads to the Great Lakes. However, toxic substances in bottom sediments continue to impair sediment and water quality and may contribute to toxic effects in aquatic biota and, potentially, in humans. Areas in the Great Lakes that remain seriously impaired have been designated as “areas of concern” (AOCs) under the Great Lakes Water Quality Agreement (U.S. Environmental Protection Agency (USEPA) 1988). Public support for control of pollution in these AOCs has prompted increased attention by Government agencies and environ mental organizations toward development of plans for remediation.

The Water Quality Act of 1987, which amended the Federal Water Pollution Control Act, authorized a program specifically aimed at the contaminated sediment problems in the Great Lakes AOCs. Section 118, paragraph (c) (3), directed the USEPA Great Lakes National Program Office (GLNPO) to study and demonstrate remediation of contaminated sediments in the Great Lakes. The Act specified that priority AOCs for implementation of demonstration projects were Saginaw Bay, Michigan; Sheboygan Harbor, Wisconsin; Grand Calumet River, Indiana; Ashtabula River, Ohio; and Buffalo River, New York.

The GLNPO program authorized by Section 118 has been named “Assessment and Remediation of Contaminated Sediments (ARCS) Program. ” The following objectives were developed for the ARCS program:

1. Assess the nature and extent of bottom sediment contamination at Great Lakes AOCs.
2. Evaluate and demonstrate remedial options including removal, immobilization, and advanced treatment technologies, as well as the no-action alternative.
3. Provide guidance to the various levels of government in the United States and Canada in the implementation of remedial action plans for the AOCs in their jurisdictions, as well as direction for future evaluations in other areas, including how to assess the need for action, options available, selection of appropriate remedial measures.

U.S. Army Corps of Engineers involvement

The U.S. Army Corps of Engineers (USACE) in fulfilling its mission to maintain, improve, and extend navigable waters in the United States dredges, relocates, and disposes 191 to 229 million cubic meters of sediment annually (Engler, Patin, and Theriot 1990). In addition, the USACE regulates the discharge of dredged and fill material in the waters of the United States involving 115 to 153 million cubic meters annually (Engler, Patin, and Theriot 1990). Most of the material dredged each year is suitable for a wide variety of beneficial uses and open-water disposal (Francingues et al. 1985). The presence of heavy metals and organic chemicals in about 10 percent of the materials dredged requires special handling and site-specific restrictions on disposal operations.

Although the USACE is responsible for and regulates dredge and fill activities in the waters of the United States, the lead responsibility for the development of environmental guidelines and criteria for regulating the discharge of dredged and fill material to the waters of the United States was legislatively assigned to the USEPA. The USEPA develops regulations for dredge and fill activities in consultation or conjunction with the USACE. In addition, the USEPA has an oversight role in the USACE regulatory program.

The need to evaluate pollutant potential and disposal alternatives has prompted the development and continued improvement of procedures and supporting laboratory tests for predicting environmental impacts of dredging and dredged material disposal by the USACE. USACE and USEPA concerns over the possibility of adverse environmental effects of dredged material disposal were evident as early as 1966 when an investigation of water quality problems in the Great Lakes was conducted by the U.S. Army Engineer District, Buffalo, in cooperation with the Federal Water Pollution Control Administration (now the USEPA) (U.S. Army Engineer District, Buffalo 1969). This work identified alternatives to open-water disposal of contaminated dredged material in the Great Lakes.

Between 1973 and 1978, a USACE laboratory, the U.S. Army Engineer Waterways Experiment Station (WES), conducted a national program of laboratory and field investigations on the environmental effects of dredged material disposal (Dredged Material Research Program (DMRP)). The DMRP produced first-generation procedures for preproject evaluation of the environ mental consequences of dredging and dredged material disposal. Following the DMRP effort, research and technology transfer programs, such as the Long-Term Effects of Dredging Operations (LEDO) and Dredging Operations Technical Support (DOTS) programs, were implemented by the USACE at WES. LEDO focuses on development, refinement, and field application of procedures for estimating the environmental effects of dredging operations, and DOTS is a direct field assistance and technology transfer vehicle to assist USACE Districts.

Between 1981 and 1987, a cooperative field verification program (FVP) among the U.S. Army Engineer Division, New England, WES, and the USEPA Environmental Research Laboratory, Narragansett, RI (ERLN), was conducted using contaminated dredged material from Black Rock Harbor at Bridgeport Harbor, Connecticut. FVP results showed that laboratory methods for predicting effluent and runoff water quality and plant toxicity in upland disposal sites compared well with field results (Peddicord 1988). WES has also been involved in extensive dredging and disposal alternative assessments for Indiana Harbor, Indiana (Environmental Laboratory 1987), Everett Bay, Washington (Palermo et al. 1989), and New Bedford Harbor Superfund Site, Massachusetts (Averett and Otis 1990).

Because of the experience, institutional knowledge, and technical expertise of the USACE in dealing with contaminated sediment and the history of inter agency coordination and collaboration between the USEPA and the USACE, GLNPO tasked various USACE elements for support to the ARCS Program through interagency agreements. The USACE elements involved in the ARCS Program included the U.S. Army Engineer Division, North Central, the U.S. Army Engineer District, Buffalo, the U.S. Army Engineer District, Chicago, the U.S. Army Engineer District, Detroit, and WES. The USACE primary involvement was through ARCS Program technical groups, such as the Engineering/Technology Work Group (ETWG) .

Engineering/Technology Work Group

The ETWG was one of three technical work groups within the ARCS Program that identified and prioritized tasks to be accomplished in support of overall program objectives. The ETWG was responsible for design, demonstration, and evaluation of remedial options for removing, treating, and disposing contaminated sediment. Selecting a remedial alternative requires evaluation of pollutant releases so that alternatives can be compared and the resulting ecological and human health risks can be evaluated. The best alter native is the alternative that minimizes contaminant losses and risks while maximizing treatment and/or containment effectiveness, but no alternative presents zero losses or zero risks.

In recognition of the need for estimating and evaluating contaminant losses associated with various remedial options, ETWG tasked WES and the USEPA Environmental Research Laboratory, Athens, GA (ERL-A), to develop generic procedures for estimating contaminant losses from components of remediation alternatives. These procedures were needed for preproject evaluation of the performance characteristics of remedial alternatives and in other ARCS studies for the purpose of estimating their associated risks.

0bjectives

The overall objective of this study was to develop procedures for making comparative estimates of contaminant losses from components of remedial alternatives for contaminated sediments based on existing predictive techniques and reported case studies. Supporting objectives were as follows:

1. Identify migration pathways associated with contaminant release.
2. Identify generic predictive techniques for contaminant release during stages of remediation for various alternatives, including the no-action alternative.
3. Evaluate the applicability and reliability of predictive techniques for contaminant releases associated with remediation of contaminated sediment.
4. Develop example contaminant release calculations for remedial alternatives at a selected AOC.

Application of a sediment remediation technology at any site will require a series of steps or components. For most sediment treatment alternatives, these components have been identified as follows (Averett et al. 1990):

1. Removal (Dredging).
2. Transport.
3. Pretreatment.
4. Treatment.
5. Disposal.
6. Effluent/Leachate Treatment.

The ability to quantify losses varies from component to component and within remediation components among migration pathways. Some alternatives, such as in situ capping, do not involve these components. For such alternatives, special contaminant loss estimation procedures are required.

Scope

This study was conducted as a desktop review and analysis of available predictive techniques for contaminant losses from components of remedial alternatives. The predictive techniques identified in this study include laboratory tests, simple focused vignette models, and existing contaminant transport models. No laboratory or field data collection was performed in this study. Predictive techniques for losses to air, surface water, and groundwater are identified and described in this report. Transport in air and water outside the physical boundaries of a remediation component was not modeled. In addition, plant and animal uptake were not evaluated. This report does not pro vide estimates of risks. The focus is on identifying and applying quantitative predictive techniques for developing the numerical information needed to evaluate risks. The Risk Assessment and Modeling Work Group of the ARCS Program addressed the issues of comparative risk calculations and their use in making remediation decisions. The reader is referred to the report “ARCS Risk Assessment and Modeling Overview Document” (USEPA 1993a) for more details.

This report includes evaluation of the research and development behind the available predictive techniques for various components and, hence, the relative reliability of these techniques. This report, however, does not include statistical analysis of the uncertainty associated with using the predictive techniques.

Report contents

Following this introduction are 10 parts. Contaminant Losses During Dredging describes procedures for estimating losses during dredging. Contaminant Losses During Dredged Material Transport deals with losses during dredged material transportation. Contaminant Losses During Pretreatment describes procedures for estimating losses during pretreatment. The procedures in Contaminant Losses During Pretreatment are also applicable to con fined disposal facilities. Losses From Confined Disposal Facilities describes the performance characteristics of confined disposal facilities. Contaminant Losses for In Situ Capping and Capped Disposal describes procedures for estimating losses associated with the in situ capping alternatives. Contaminant Losses During Effluent and Leachate Treatment describes procedures for estimating losses associated with treatment of effluent and leachate from pretreatment and confined disposal facilities. Contaminant Losses for the No-Action Alternative provides an overview of the models applicable to no-action assessments. Dredged Material Treatment describes assessment techniques for treatment alternatives. Example Application to Contaminated Sediments in the Buffalo River presents example calculations of contaminant losses. Summary and Recommendations provides concluding remarks about the procedures described in Contaminant Losses During Dredging through Dredged Material Treatment and the results obtained in Example Application To Contaminated Sediments in the Buffalo River. There are three appendices: Appendix A: Notation; Appendix B: A Priori Estimation of Distribution Coefficients; and Appendix C: Input Parameters for Open-Water Disposal Models.

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