R. B. Cook, M. L. Frank, L. A. Kszos, S. M. Adams, M. J. Gentry, R. F. Lehew, J. J. Beauchamp, M. S. Greeley, D. A. Levine, M. S. Bevelhimer, R. S. HaLbrook, K. Murray, B. G. Blaylock, R. A. Harris, T. L. Phipps, C. C. Brandt, S. K. Holladay, J. L. Skiles, E. L. Etnier, L. A. Hook, G. W. Suter, C. J. Ford, P. L. Howell
Date Issued--August 1993
This document contains a three-part addendum to the Clinch River Resource Conservation and Recovery Act (RCRA) Facility Investigation Plan. The Clinch River RCRA Facility Investigation began in 1989, as part of the comprehensive remediation of facilities on the U.S. Department of Energy Oak Ridge Reservation (ORR). The ORR was added to the National Priorities List in December 1989. The regulatory agencies have encouraged the adoption of Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) terminology; therefore, the Clinch River activity is now referred to as the Clinch River Remedial Investigation (CRRI), not the Clinch River RCRA Facility Investigation.
At the time of the approval of the Phase II Sampling and Analysis Plan an effort is underway to implement the EPA Data Quality Objectives Process (DQO) which is directed at ensuring that only the data sufficient to make remedial decisions is collected. This process is being implemented cooperatively with DOE Oak Ridge Operations, DOE Headquarters, EPA Region IV, EPA Headquarters, the State of Tennessee, and the public. It is anticipated that the outcome of the DQO process may result in changes to sampling strategy. For this reason, the current plan will be issued as a controlled document subject to further revision.
Part I of this document is the plan for sampling and analysis (S&A) during Phase 2 of the CRRI. Part II is a revision of the Quality Assurance Project Plan for the CRRI, and Part III is a revision of the Environmental Health and Safety Plan for the CRRI.
The CRRI is designed to address the transport, fate, and distribution of waterborne contaminants released from the ORR and to assess potential risks to human health and the environment associated with these contaminants. The contaminants released since the early 1940s include a variety of radionuclides, metals, and organic compounds. Primary areas of investigation are Melton Hill Reservoir, the Clinch River from Melton Hill Dam to its confluence with the Tennessee River, Poplar Creek, and the Watts Bar Reservoir. The contaminants identified in the Clinch River/Watts Bar Reservoir (CR/WBR) downstream of the ORR are those associated with the water, suspended particles, deposited sediments, aquatic organisms, and wildlife feeding on aquatic organisms.
A phased remedial investigation of the CR/WBR system is under way to (1) define the nature and extent of the off-site contamination, (2) evaluate associated environmental and human health risks, and (3) preliminarily identify and evaluate potential remediation alternatives.
Phase 1 of the CRRI was a preliminary S&A of fish, sediment, and water in selected areas of the CR/WBR chosen to represent differing levels of media contamination. Specifically, Phase 1 was designed to (1) obtain high-quality data to confirm existing data for contaminant levels in fish, sediment, and water form the CR/WBR; (2) determine the range of contaminant concentrations present in the river-reservoir system; (3) identify specific contaminants of concern; and (4) establish the reference (background) concentrations for those contaminants. The results of Phase 1 of the CRRI provide a specific, technically valid determination of the contaminants, media, and transport and exposure pathways in the CR/WBR environment that require further assessment during Phase 2 prior to a decision on the potential need for remediation. The Phase 1 data are summarized and discussed in Cook et al. (1992).
During the Phase 2 investigation, additional S&A will be conducted for site characterization and risk analysis as identified by Phase 1 results. The purpose of the CRRI Phase 2 S&A Plan is present the proposed approach for (1) defining the extent of the contaminants of concern in sediment, water, and biota; (2) determining the human-health and ecological risks potentially associated with the contaminants of concern; and (3) providing specific data to support the evaluation of potential remediation measures in specific sites of concern.
The objectives of the Phase 2 study are (1) to perform iterative screening risk analyses as additional data become available, (2) to quantitatively estimate potential risks to human and ecological health, and (3) to focus additional sampling efforts. A phased approach will also be employed in Phase 2 to permit a continued, progressive focusing f Remedial Investigation (RI) activities on the contaminants, media, and areas of greatest concern. These screening-level risk analyses will guide more extensive S&A and risk assessment, ultimately leading to a baseline risk assessment and RI final report. Ecological assessments of risk, toxicity, and ecophysiological and reproductive effects and estimates of the effects of contaminants in the food web will also be performed. In addition, the Phase 2 study will include a preliminary evaluation of potential remediation alternatives and an identification of effective and acceptable corrective measures.
Predictive models will also be used during the Phase 2 investigation to assess (1) contaminant transport and fate in the CR/WBR, (2) remobilization of contaminants form deposited sediments, (3) potential impacts of various risk scenarios, and (4) the risk-reduction potential of remediation alternatives. Specific data collection tasks to support these predictive models will also be performed during Phase 2 of the CRRI.
Screening for human and ecological health using the Phase 1 water data, in combination with monitoring data from the ORR, did not eliminate contaminants from further consideration. Additional water sampling must be performed during the Phase 2 investigation to provide enough information to conduct a baseline risk assessment. The Phase 2 surface-water S&A tasks will focus on (1) a rigorous characterization of reference sites, (2) improving the detection limits for contaminants that are present at low concentrations that potentially may pose a risk to human or ecological health, (3) testing of the toxicity of ambient surface water, (4) measurement of off-site contaminants in conjunction with on-site monitoring, and (5) characterization of spatial-temporal trends in particle-associated contaminants downstream of the ORR.
The specific tasks to be performed as part of the Phase 2 water S&A will be (1) an investigation of current contaminant sources to Melton Hill Reservoir, Watts Bar Reservoir, and Poplar Creek; (2) measurement of temporal and spatial changes in Watts Bar Reservoir contaminant content and water quality; (3) quantification of the contaminant content of suspended matter in conjunction with testing the toxicity of ambient water; and (4) measurement of contaminant-associated parameters with distance downstream from contaminant sources on the ORR.
The purpose of the sediment characterization task in Phase 2 of the CRRI is to describe the nature and extent of contamination in the sediment of the CR/WBR system, to evaluate the effects of contamination on ecological and human health, and to identify and evaluate remedial action alternatives. Most contaminants of concern are chemically and biologically reactive and rapidly become associated with particles in freshwater systems. consequently, uptake or sorption onto particles is the primary mechanism for removing chemically reactive contaminants from the water column, and sedimentation is the principal mechanism for the accumulation of these contaminants in off-site areas over long time periods.
Risk screening analysis of Phase 1 sediment data indicate that in specific reaches 137Cs, 60Co, 234U, 235U, 238U, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, thallium, zinc, Aroclor-1254, anthracene, flouranthene, phananthrene, and pyrene all require further study before a determination can be made on whether remediation is required. Phase 2 sampling for sediments will focus on identifying the geographic distribution of these contaminants and quantifying the amounts of these contaminants in the sediments.
There are four tasks within the Phase 2 sediment characterization plan aimed specifically at addressing each part of the overall goal of the sediment characterization project. These tasks include extended sediment S&A, near-shore sediment characterization, sediment toxicity, and sediment-transport modeling.
The extended sediment S&A task is designed to focus on the contaminants of concern for specific reaches, with the goal of limiting the area of concern and the number of contaminants with which to be concerned. Phase 1 results indicate that sampling for this task should focus on the Clinch River arm of Watts Bar Reservoir and Poplar Creek. Additional reference samples will be collected from several reaches to meet minimum statistical requirements for comparability. At minimum, three core are required from a reach to allow valid statistical comparisons between reference reaches and "contaminated reaches." The exact number of samples required is a function of the spatial variability of contaminants in the sediments, which will be determined early in Phase 2.
The near-shore sediment characterization task will continue to provide measurement of contaminants in sediments that may result in direct exposure to humans. Areas in the Clinch River arm of Watts bar Reservoir identified during Phase 1 S&A as having high 137Cs concentrations will be resampled to determine if other contaminants are present.
The sediment toxicity task will provide critical additional data for ecological risk assessment. Toxicity testing will be performed using sediment and water from the Clinch River, downstream of White Oak Creek, and Poplar Creek below discharge points permitted under the National Pollutant Discharge Elimination System (NPDES) and DOE Order 5400.1. If toxicity to aquatic organisms is found in these sites, sampling and toxicity tests will be extended downstream until no toxic effects are detected.
The sediment-transport modeling task will provide a tool to understanding sediment and contaminant movement in the system and will allow remediation alternatives to be evaluated. S&A for this subtask will focus on determining characteristic ranges of particle size distributions, critical sheer-stress, and total organic content for the five major sediment types found in Watts Bar Reservoir.
The principal objectives of the biological component of the Phase 2 S&A Plan are to (1) further characterize the nature and extent of contamination in biota from the CR/WBR system, (2) evaluate the effects of this contamination on key ecological species, and (3) identify important pathways of contaminant transport within the food web. These objectives will be accomplished through the application of five interrelated tasks, which in turn will provide information for human health and ecological risk assessments and for the preliminary evaluation of potential remedial action alternatives. The five tasks are expanded fish S&A, bioindicator analysis, reproductive effects assessment, other biota (Great Blue Heron, waterfowl, mink), and contaminant pathways in food webs.
The objective of the fish S&A task is to determine the extent to which key fish species in th CR/WBR system are contaminated by past and present toxicant releases from the ORR. Gamefish from selected sites throughout the CR/WBR system and reference areas unaffected by the ORR will be sampled and analyzed for priority contaminants (including polychlorinated biphenyls, chlordane, and mercury) that were identified in Phase 1 as those of human health and ecological concern.
The primary objective of the reproductive effects assessment task is to determine the reproductive health of fish in the CR/WBR downstream of the ORR through a comparison of selected reproductive criteria in key fish. A secondary objective of this task is to examine the potential for fish embryo and larval development to be adversely affected by water in the CR/WBR downstream of the ORR. This will be accomplished by exposing fish embryos to surface water from different locations within the system during embryonic and early larval development and examining subsequent developmental responses.
The other biota task is composed of separate studies on waterfowl, great blue heron, and mink. The primary objectives of the waterfowl study are to (1) determine the concentrations of radionuclides and other contaminants in waterfowl (geese and ducks) taken from the ORR and reference areas, (2) determine the range and movement patterns of individual members of the resident goose populations, and (3) estimate the probability of a hunter harvesting a waterfowl that has resided on the ORR. This study will entail collection and contaminant analysis of waterfowl, tagging and weekly census, and hunter and hunting area surveys. The objective of the heron study is to determine the extent to which herons nesting within or adjacent to the ORR are contaminated by exposure to past and present releases from the ORR. Eggs and chicks collected from nests within the ORR and from reference nests will be analyzed for specific contaminants of ecological concern, and a suite of biomarkers will be used to assess the health of the heron populations. The objective of the mink study is to estimate any adverse effects on mink that reside on the ORR and feed from contaminated areas of the CR/WBR system. Physiological, biomarker, and reproductive effects will be compared among groups of captive mink that have been fed diets consisting of fish from downstream and upstream of the ORR and ocean fish.
The objective of the food-web task is to identify the important sources and pathways of contaminant transport, movement, and bioaccumulation within CR/WBR food webs. The approach includes (1) collection and chemical analysis of organisms that are lower in the food chain than those sampled in other tasks (primarily crayfish and benthic insects) and (2) simulation modeling to evaluate the underlying mechanisms of contaminant uptake by key species and the relative contributions of waterborne and sediment-borne contaminants to the total body burden.
The information collected for each of the water, sediment, and biota, tasks in Phase 2 of the CRRI will be analyzed in a step-wise fashion using iterative screening-level risk assessments for human health and the environment. The results of each round of risk assessment will be used to progressively focus additional Phase 2 S&A on those contaminants, media, exposure pathways, and river/reservoir areas of primary concern. The iterative risk assessments will eventually narrow the scope of S&A during the last stages of the Phase 2 investigation to those contaminants that pose an unacceptable risk to human health and the environment. Phase 2 will also evaluate potential remedial action alternative and identify effective and acceptable corrective measures. An RI final report will be issued that presents a baseline risk assessment and an evaluation of the potential remedial action alternative. The RI report is currently scheduled to be transmitted to Environmental Protection Agency and Tennessee Department of Environment and Conservation for review and approval in September 1995.