Sediments

Valence state: The combining capacity of an atom or radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.

Source: The American Heritage™ Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.

free product: A NAPL found in the subsurface in sufficient quantity that it can be partially recovered by pumping or gravity drain.

aerobic: Direct aerobic metabolism involves microbial reactions that require oxygen to go forward. The bacteria uses a carbon substrate as the electron donor and oxygen as the electron acceptor. Degradation of contaminants that are susceptible to aerobic degradation but not anaerobic often ceases in the vicinity of the source zone because of oxygen depletion. This can sometimes be reversed by adding oxygen in the form of air (air sparging, bioventing), ozone, or slow oxygen release compound (e.g., ORC(r)).

Aerobic dechlorination may also occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal. For aerobic cometabolism to occur there must be sufficient oxygen and a suitable substrate which allows the microbe to produce the appropriate enzyme. These conditions may be present naturally but often in the presence of a source area oxygen and a substrate such as methane or propane will need to be introduced.

Adapted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites

anaerobic: Direct anaerobic metabolism involves microbial reactions occurring in the absence of oxygen and encompasses many processes, including fermentation, methanogenesis, reductive dechlorination, sulfate-reducing activities, and denitrification. Depending on the contaminant of concern, a subset of these activities may be cultivated. In anaerobic metabolism, nitrate, sulfate, carbon dioxide, oxidized metals, or organic compounds may replace oxygen as the electron acceptor.

Anaerobic dechlorination also may occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal.

Quoted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites

architecture: "Architecture" refers to the physical distribution of the contaminant in the subsurface. Residuals that take the form of long thin ganglia or small dispersed globules provide a larger surface area that will dissolve much faster than if the same amount of liquid were concentrated in a competent pool.

Sources: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.

source zone: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.

focal ulceration: The process or fact of a localized area being eroded away.

metaplasia of the glandular stomach: A change of cells to a form that does not normally occur in the tissue in which it is found.

hyperplasia of the glandular stomach: A condition in which there is an increase in the number of normal cells in a tissue or organ.

histiocytic: Degenerative.

duodenum: First part of the small intestine.

microcytic: Any abnormally small cell.

squamous cell papillomas: A small solid benign tumor with a clear-cut border that projects above the surrounding tissue.

squamous cell carcinomas: Cancer that begins in squamous cells-thin, flat cells that look under the microscope like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of hollow organs of the body, and the passages of the respiratory and digestive tracts. Squamous cell carcinomas may arise in any of these tissues.

jejunum: The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum.

ileum: The distal and narrowest portion of the small intestine.

squamous: Flat cells that look like fish scales.

metaplasia: A condition in which there is a change of one adult cell type to another similar adult cell type.

ossification: The process of creating bone, that is of transforming cartilage (or fibrous tissue) into bone.

clastogenesis: Any process resulting in the breakage of chromosomes.

neoplastic: Abnormal and uncontrolled growth of cells.

ulceration: The process or fact of being eroded away.

leucocytosis: An elevation of the total number of white cells in blood.

neutrophils: A type of white blood cell.

chromodulin: A small protein that binds four trivalent chromium ions.

biomagnification: The increased accumulation and concentration of a contaminant at higher levels of the food chain; organisms higher on the food chain will have larger amounts of contaminants than those lower on the food chain, because the contaminants are not eliminated or broken down into other chemicals within the organisms.

exencephaly: Cerebral tissue herniation through a congenital or acquired defect in the skull.

everted viscera: Rotated body organs in the chest cavity.

To Be Considered: Documents, such as federal or state guidances, that are not legally binding but may be relevant to the topic in question.

gaining: A gaining surface water body is one where groundwater flows into it.

losing: A surface water body is losing when there is a permeable sediment bed that is not in contact with the groundwater allowing the surface water to seep through it.

fluvial: Of or pertaining to flow in rivers and streams.

lacustrine: Of or pertaining to a lake as in lacustrine sediments—sediments at the bottom of a lake.

lipid: Any class of fats that are insoluble in water.

lipophilic: Able to dissolve in lipids—in this case fatty tissue.

organelles: A part of a cell such as mitochondrion, vacuole, or chloroplast that plays a specific role in how the cell functions and membranes.

RfD: The RfD is an estimate of a daily exposure of the human population (including sensitive sub-groups) to a substance that is likely to be without "the appreciable risk of deleterious effects during a lifetime." An RfD is expressed in units of mg/kg-day.

autonomic: That part of the nervous system that controls non-conscious actions such as heart rate, perspiration and digestion.

ataxia: Lack of muscle coordination.

funnel-and-gate configuration: A system where low-permeability walls (the funnel) placed in the saturated zone direct contaminated ground-water toward a permeable treatment zone (the gate)

References: ATSDR (Agency for Toxic Substances and Disease Registry). 2015. Draft Toxicological Profile for Perfluoroalkyls. 574 pp.

EFSA (European Food Safety Authority). 2008. Opinion of the scientific panel on contaminants in the food chain on perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and their salts. EFSA Journal 653:1-131.

Hekster, F.M., R.W.P.M. Laane, and P. de Voogt. 2003. Environmental and toxicity effects of perfluoroalkylated substances. Reviews of Environmental Contamination and Toxicology 179:99-121.

Higgins, C. and R. Luthy. 2006. Sorption of perfluorinated surfactants on sediments. Environmental Science & Technology 40(23):7251-7256.

HSDB (Hazardous Substances Data Bank). 2012 Update. Perfluorooctanoic acid.

Kaiser, M.A., B.S. Larsen, C-P.C. Kao, and R.C. Buck. 2005. Vapor pressures of perfluorooctanoic, -nonanoic, -decanoic, -undecanoic, and -dodecanoic acids. Journal of Chemical and Engineering Data 50(6):1841-1843.

Kauck, E.A. and A.R. Diesslin. 1951. Some properties of perfluorocarboxylic acids. Industrial and Engineering Chemical Research 43(10):2332-2334.

Lewis, R.J., Sr., ed. 2004. Sax's Dangerous Properties of Industrial Materials. 11th ed. Wiley-Interscience, Hoboken, NJ. V3:2860.

Lide, D.R. 2007. CRC Handbook of Chemistry and Physics. 88th ed. CRC Press, Boca Raton, FL. 3-412.

SRC (Syracuse Research Corporation). 2016. PHYSPROP Database. SRC Scientific Databases, Accessed May 2016.

UNEP (United Nations Environmental Program). 2015. Proposal to List Pentadecafluorooctanoic Acid (CAS No: 335-67-1, PFOA, Perfluorooctanoic Acid), Its Salts and PFOA-Related Compounds in Annexes A, B and/or C to the Stockholm Convention on Persistent Organic Pollutants. UNEP/POPS/POPRC.11/5.

USEPA (U.S. Environmental Protection Agency). 2016. Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA).#pdfsmall# Office of Water, EPA 822-R-16-005, 103 pp

• Overview
• Policy and Guidance
• Conceptual Site Models
• Fate and Transport of Contaminants
• Site Characterization
• Risk Assessment
• Remediation
• Additional Resources

---

• Issue Areas Home
• Suggest Resource

The fate and transport of contaminants in sediments often involve very complex processes that depend on the physical/chemical properties of the contaminant and sediments, as well as the type of water body the sediments rest in. In general, the more hydrophobic (higher octanol water partition coefficient (K_ow)), less polar, and larger an organic contaminant molecule, the less likely it is to biodegrade and the more likely it is to adhere to sediment particles and sediment organic carbon matter. As a result, these persistent organic contaminants are likely to bioaccumulate (EPA 2000).

Another class of contaminants, halogenated hydrocarbons (such as chlorinated solvents), can contaminate sediments when the groundwater they are dissolved in discharges to surface water after passing through the sediments. Sediments with moderate to high clay or organic carbon content tend to sorb some of the dissolved contaminants and continue to be a source of contamination long after the upland source is depleted.

Metals can become part of the sediment mass through precipitation (e.g., carbonates, sulfides, phosphates, hydroxl complexes) or adsorption (e.g., clay, sediment organic matter). In most cases a radical change in the sediment geochemistry (falling pH, change in redox) may result in their resuspension as ions. Some metals (e.g., arsenic, cadmium, lead, selenium, zinc) bioaccumulate, while others do not (e.g., copper, nickel). Atmospheric mercury deposited into surface water can undergo biotransformation in sediments to highly bioaccumulative and toxic methylmercury. Information, as given above, on bioaccumulation and fate and transport of specific metals may be found in their ASTDR toxicological profiles.

The transport of contaminants associated with sediments is highly dependent upon the type of surface water involved and the source of contamination. Sediment transport in fluvial systems generally occurs as suspended and bed loads, which are affected by current velocity. The suspended load consists of very fine sands, silts, clays and associated organic matter, while the bed load is made up of larger particles. Suspended sediments, which account for the greatest contaminant mass, have the ability to move large distances before settling out of the water column. Settlement occurs in deposition areas of streams and rivers when water energy levels fall or in the deltas of streams and rivers of a lacustrine or marine environment when water meets its discharge point (NAVFAC 2004). Sediments in Lake Hartwell, South Carolina, for instance, have been contaminated from creek discharge laden with PCB-contaminated sediments.

The transport of contaminated sediments in near-shore lacustrine and marine areas may be affected by wave energy flux, tidal energy flux, wind forced currents, and subsurface currents as well as the topography found on the water body floor (NAVFAC 2004 and USEPA 2005).

Contaminated sediments have the ability to affect the quality of groundwater and surface water. Water from a water body in a losing system passes through the sediments picking up contaminants dissolved in the sediment pore water and potentially carrying them down to groundwater. Groundwater passing through sediments in a gaining water body can carry contaminants dissolved in the sediment pore water up into the water body.

---

EPA. 2000. Bioaccumulation Testing and Interpretation for the Purpose of Sediment Quality Assessment Status and Needs, EPA-823-R-00-001. Office of Water, 136 pp.

USEPA. 2005. Contaminated Sediment Remediation Guidance for Hazardous Waste Sites, EPA-540-R-05-012. Office of Superfund Remediation and Technology Innovation, 236 pp.

General Documents

Assessment and Management of Stormwater Impacts on Sediment Recontamination
Reible, D., B. Rao, M. Rakowska, D. Athanasiou, I. Drygiannaki, M. Bejar, B. Chadwick, et al.
SERDP Project ER-2428, 1840 pp, 2018

This project was conducted to develop, test, and assess the effectiveness of a comprehensive set of lab, field, and modeling approaches in characterizing the role of urban stormwater in contamination of sediments and recontamination of remediated sites. The report is organized by the tools and measurements as related to the understanding gained in their use. Additional information: Assessment and Management Guide

Demonstration of Fluorescent Magnetic Particles for Linking Sources to Sediments at DoD Sites
Leather, J.
ESTCP Project ER-201214, 250 pp, 2018

To demonstrate a particle tracking technology for quantitative mapping of the spatiotemporal distribution and depositional footprint of particles released from typical DoD contaminant sources into adjacent aquatic environments, fluorescent ferromagnetic particles were released from specific sources, tracked through the water column, and collected at the sediment surface. The particles then were analyzed to determine their spatial distribution and depositional pattern and demonstrate quantitatively the linkage between sources and receiving water areas where the particle sources were most likely to impact the sediments. Additional information: ESTCP Cost and Performance Report

Demonstration of New Tools for Improved Source and Recontamination Potential Assessment
Chadwick, B. and M. Arias-Thode.
ESTCP Project ER-201432, 2355 pp, 2017

A family of technologies adapted from the oceanographic and environmental arenas was combined to improve DoD's ability to address sediment contaminant source exposure, transport, and fate challenges at coastal sites in a relatively simple and cost-effective way. The demonstration focused on the following three key technologies: (1) Drifting Exposure System - a surface global positioning system (GPS) drifter with position data telemetry, composite sample collection, and passive sampler capabilities for exposure characterization. (2) Drifting Particle Simulator - a GPS drifter with position data telemetry, buoyancy control, bottom detection, and passive sampling capability for measurement of depositional footprints and sampling of source-related particles. (3) Sediment Deposition Detector - a sediment bed scour sensor with high-resolution differential pressure sensor, shore cable or in situ data logging, and coupled sediment trap capabilities. Field demonstrations were conducted at Naval Base San Diego (Paleta Creek) and Joint Base Pearl Harbor Hickam (Oscar Pier and Waiau Power Plant Area). Additional information: ESTCP Cost and Performance Report

Evaluating Potential Exposures to Ecological Receptors Due to Transport of Hydrophobic Organic Contaminants in Subsurface Systems
Ford, R.G., M.C. Brooks, C.G. Enfield, and M. Kravitz.
EPA 600-R-10-015, 69 pp, 2014

Detailed discussion of enhanced transport mechanisms is the focus of this technical paper. It recommends several types of screening assessments to evaluate site conditions for the potential to enhance transport of HOCs—PCBs, dioxins, fuels (including the influence of MTBE), and creosote and tar DNAPL—as well as site artifacts that result from inadequate well installation and sampling procedures within a groundwater monitoring network. These assessments are incorporated into a suggested three-tiered decision analysis process that provides a summarized view of the upland contaminant-source characteristics that need evaluation to establish whether facilitated transport of HOCs might occur at a given site.

Manual to Identify Sources of Fluvial Sediment
Gellis, A., F. Fitzpatrick, and J. Schubauer-Berigan.
EPA 600-R-16-210, 117 pp, 2016

Sediment can degrade and alter aquatic habitat. A sediment budget is an accounting of the sources, storage, and export of sediment over a defined spatial and temporal scale. This manual focuses on field approaches to estimate a sediment budget. This guide for sediment source analysis synthesizes studies that incorporate sediment fingerprinting and sediment budget approaches in agricultural and urban watersheds.

User's Guide for Assessing Sediment Transport at Navy Facilities
Blake, A.C., D.B. Chadwick, P.J. White, and C.A. Jones.
NAVFAC, Space and Naval Warfare Systems Command, Technical Report 1960, 165 pp, 2007

The purpose of this guide is to provide Navy Remedial Project Managers and their technical support staff with practical guidance on planning and conducting sediment transport evaluations. The guide identifies and reviews methods and tools to characterize sediment transport, and it provides a framework that can be used to identify the types of measurements and data analysis methods applicable for a contaminated sediment site. The final section provides guidance on how the results of a well-designed sediment transport evaluation may be used to develop management decisions for contaminated sediment sites.

Toxicological Exposure of Sediment-Bound Hydrophobic Organic Contaminants as a Function of the Quality of Sediment Organic Carbon and Microbial Degradation
Fredrickson, H.L., J.W. Talley, J.S. Furey, and S. Nicholl
U.S. Army Corps of Engineers, ERDC/TN EEDP-04-34, 17 pp, 2003

This paper relates the importance of the toxicological exposure potential of hydrophobic organic contaminants (HOC) in sediments and dredged material to the implementation of public laws and regulations governing environmental risk assessment. It summarizes the peer-reviewed literature on sediment HOC exposure potential in the context of the sorbant quality of sediment organic carbon and microbial degradation. It also describes the practical utility of using thermal desorption mass spectrometry to identify and quantify HOC.

Groundwater-Surface Water Interactions

Accounting for the Groundwater-Surface Water Interface in Contaminated Land Assessments
Ibrahim, T., D. Lerner, and S. Thornton, Catchment Science Centre, Univ. of Sheffield, UK.
Contaminated Land: Applications in Real Environments (CL:AIRE), TB15, 8 pp, Oct 2011

ECO Update / Groundwater Forum Issue Paper: Evaluating Ground-Water/Surface-Water Transition Zones in Ecological Risk Assessments
EPA, EPA-540-R-06-072, 30 pp 2008

Ground Water and Surface Water a Single Resource
Winter, Thomas C. et al.
USGS (US Geological Survey), Circular 1139, 87 pp, 1998

The Hyporheic Handbook: A Handbook on the Groundwater-Surfacewater Interface and Hyporheic Zone for Environmental Managers
Buss, S., Z. Cai, B Cardenas, et al.
Environment Agency, Bristol, UK. Science Report SC050070, 280 pp, 2009

Proceedings of the Ground-Water/Surface-Water Interactions Workshop
EPA, EPA 542-R-00-007, 204 pp, 2000

Hyporheic Network
EPA, EPA 542-R-00-007, 204 pp, 2000

A knowledge transfer network on groundwater- surface water interactions and hyporheic zone processes

Contaminants

This section contains information that may be useful in understanding the fate and transport of classes of chemical contaminants that are commonly found in sediments.

Lake Michigan Lake Wide Management Plan (LaMP 2000), Appendix B Physical and Chemical Properties
USEPA, 90 pp, 2000

This appendix provides a general discussion of specific contaminants that are frequently found in Lake Michigan. Besides giving a brief discussion of chemical origins and deposition, it also has tables that summarize their physical properties (e.g. solubility, K_ow, bioaccumulation factor).

Metals

Under proper pH conditions in an oxic environment, free ions of most metals tend to form salts and hydroxyl complexes that settle out of solution. These particulates are easily resuspended when the sediments are disturbed. A shallow layer of oxic sediments followed by an increasingly anoxic condition exists in some water bodies, especially if there is a high organic carbon content. The oxic layer contains salts, such as phosphates, sulfates, and carbonates, as well as metal complexes, such as those formed with ferric hydroxyls. In anoxic sulfate reducing conditions, several metals bond with sulfide ions and iron sulfides to form insoluble compounds. The sulfides may dissolve into their ionic state when exposed to oxic conditions (Carroll et al., 2002). The presence of iron and manganese oxides in the sediment matrix is also important for binding metals (Ford et al., 2005).

Wetland sediments can become sinks for heavy metals. The low energy of the water allows for the settling out of suspended solids containing heavy metals. The complex interaction of wetland biota, mineral surfaces, and organic rich sediments under oxic and anoxic conditions often leads to the removal of heavy metal ions from the overlying water.

Benthic Flux of Dissolved Nickel into the Water Column of South San Francisco Bay
Topping, B., J.S. Kuwabara, F. Parchaso, S.W. Hager, A.J. Arnsberg, and F. Murphy
USGS, Open File Report 01-89, 50 pp, 2001

Coupling Between Overlying Hydrodynamics, Bioturbation, and Biogeochemical Processes Controls Metal Mobility, Bioavailability, and Toxicity in Sediments
Packman, A.I., J.-F. Gaillard, and G.A. Burton, Jr.
SERDP Project ER-1745, 120 pp, 2016

In lab experiments performed to determine the coupled effects of hydrodynamics, bioturbation, and biogeochemical processes on the transformation, mobility, bioavailability and toxicity of metals in contaminated sediments, oxidation of surficial sediments liberated metal species that were then mobilized to both porewater and overlying water. Liberation of metals generally increased with hydrodynamic shear on the sediment-water interface, even in some low-permeability sediments. Sediment resuspension transitorily mobilized particulate metals but did not significantly mobilize dissolved metals or increase contaminant bioavailability or toxicity. Bioturbation and bioirrigation by burrowing worms, however, greatly increased sediment heterogeneity, oxygen delivery into sediments, and efflux of metals to both porewater and overlying water. Bioturbation also destabilized sediments, resulting in greater particle resuspension and metals efflux following flow perturbations. Based on these findings, the authors recommend including measurements of the effects of flow forcing and sediment resuspension in concert with biological perturbations during assessments of metals bioavailability and toxicity in contaminated sediments.

Environmental Research Brief— The Impact of Ground-Water/Surface-Water Interactions on Contaminant Transport with Application to an Arsenic Contaminated Site
Ford, Robert
EPA, Office of Research and Development, 22 pp, 2005

The Effects of Sediment and Mercury Mobilization in the South Yuba River and Humbug Creek Confluence Area, Nevada County, California: Concentrations, Speciation, and Environmental Fate
U.S. Geological Survey Open-File Reports 2010-1325A and 2010-1325B, 2011

• Part 1: Field Characterization
• Part 2: Laboratory Experiments

These reports comprehensively characterize Hg contamination at this particular site and the potential effects on downstream environments of sediment disturbance at locations with historical hydraulic mining debris. The field component assessed the potential effects of recreational suction dredging in terms of 1) its viability as an approach to clean up riverbed sediment contaminated with legacy Hg from historical gold-mining activity and 2) its effects (compared that caused by natural storm disturbances) on Hg remobilization, speciation, and the potential for the stimulation of toxic methylmercury production and bioaccumulation in downstream sediments. Hg bioaccumulation in the local invertebrate population was also evaluated. Results of the field studies indicate that the fine-grained fraction (silt-clay, less than 0.063 mm) contains the greatest concentration of Hg in contaminated sediment. Because the fine-grained fraction is the most susceptible to long-range fluvial transport, disturbance of Hg-contaminated sediment is likely to increase the concentration and load of Hg in downstream waters. As part of this larger study, lab experiments were conducted with various types of sediment collected in and around the confluence area to simulate in-stream transport, deposition, and potential methylation of Hg.

Field Study of the Fate of Arsenic, Lead, and Zinc at the Ground-Water/Surface-Water Interface
Ford, R., R.T. Wilkin, C.J. Paul, F. Beck, Jr., K.G. Scheckel, P. Clark, and T. Lee
USEPA, Office of Research and Development, EPA/600/R-05/161, 91 pp, 2005

This document illustrates several chemical processes that govern contaminant transport and speciation during water exchange across the groundwater/surface water transition zone. It focuses on the assessment of metal speciation transformations in contaminated sediments. Results from a field investigation of the fate of arsenic, lead, and zinc transported across the groundwater/surface water transition zone at a contaminated site are presented to illustrate the importance of using a site conceptual model and to provide an example of approaches that may be used to characterize the spatial and temporal distributions of inorganic contaminant speciation. The field site was located immediately downgradient from the Industri-Plex Superfund Site in Woburn, Massachusetts.

Final Report: Arsenic Fate, Transport and Stability Study, Groundwater, Surface Water, Soil and Sediment Investigation, Fort Devens Superfund Site Devens, Massachusetts
Ford, R., K.G. Scheckel, S. Acree, R. Ross, B. Lien, T. Luxton, and P. Clark
USEPA, Office of Research and Development, 193 pp, 2008

This document presents results from the Fiscal Years 2006-2007 field investigation at the Shepley's Hill Landfill Superfund site. The purpose of this study is to provide EPA Region 1 with a technical evaluation of the distribution and flux of arsenic in shallow groundwater adjacent to Red Cove and the fate, transport and stability of arsenic in sediments and surface water following groundwater discharge. Additional information: Ford et al. 2011. Delineating landfill leachate discharge to an arsenic contaminated waterway. Chemosphere 85(9):1525-1537 (Abstract).

Flux of Dissolved Forms of Mercury Across the Sediment-Water Interface in Lahontan Reservoir, Nevada
Kuwabara, J.S. and et al.
USGS, Water Resources Investigations Report 02-4138, 49 pp, 2002

Mercury Geochemistry in a Wetland and its Implications for In-situ Remediation
Kaplan, D.I., S. Knox, and J. Myers
DOE, Savannah River, WSRC-MS-2002-00056, 2002

Seasonal variations in pore water and sediment geochemistry of littoral lake sediments (Asylum Lake, MI, USA)
Koretsky, Carla M., Johnson R Haas, Douglas Miller, and Noah T Ndenga
Geochem Trans. 2006; 7: 11

This article examines seasonal variation in trace metals using peepers to collect pore water samples.

Speciation and Fate of Trace Metals in Estuarine Sediments under Reduced and Oxidized Conditions, Seaplane Lagoon, Alameda Naval Air Station (USA)
Carroll, S., P.A. O'Day, B. Esser, and S. Randal
Geochem. Trans. 2002; 3: 81

This article discusses chemical reactions that control the fate of metal-contaminated estuarine sediments and compares their fate when left undisturbed (in situ) versus when they are dredged.

Pesticides

Pesticides exhibit a wide variety of chemical/physical properties. Many are soluble and easily biodegradable. The ones that present the most problems in sediments are hydrophobic, resist biodegradation, and bioaccumulate. Barbash, 2007 presents a table on the persistence of selected pesticides.

The principal phases of partitioning between surface water and sediments are the water itself, organic matter (e.g., humic acids, decaying plant material, deposited soot), mineral surfaces (e.g., clay), and biological tissue (bioaccumulation). Sorptive interactions with organic matter are particularly important for neutral pesticide compounds, including those that can donate a hydrogen atom (Br�nsted acids) to another species. Also, some pesticides, such as glyphosate, can form relatively insoluble metal complexes and precipitate out of solution.

Transport of persistent pesticides occurs mostly through the movement of suspended or, less commonly, bed-load sediments to which they have sorbed. The deposition of these pesticide laden sediments may lead to substantial increases in the residence time of these compounds in the ecosystem.

Adapted from Barbash (2007)

The Geochemistry of Pesticides
Barbash, J.E.
USGS, 43 pp, 2007

Monitoring and Modelling the Dynamic Fate and Behaviour of Pesticides in River Systems at Catchment Scale
Holvoet, K.
Ghent University, Belgium, pp. 242.

This thesis discusses the behavior of pesticides in riverine systems as well as the development of a model for their fate prediction.

Pesticides in Stream Sediment and Aquatic Biota Current Understanding of Distribution and Major Influences
USGS, Fact Sheet 092-00, 4 pp, 2000

Pesticide National Synthesis Project
USGS, National Water Quality Assessment Program

This Web site is devoted to pesticide issues in water and sediment.

Polychlorinated Biphenyls

PCBs adhere to the surfaces of organic particles in the water column, resulting in their eventual deposition and accumulation in sediments. The highest concentrations of PCBs are typically found in fine-grained, organically rich sediments. Horizontal and vertical variations in PCB concentrations in sediments are common and are dependent on the history of PCB inputs to the ecosystem and on the temporal and spatial deposition patterns of fine- and coarse-grained sediments.

At sites without new inputs of PCBs, the greatest concentrations tend to be found below the surficial sediments, where contaminated sediments are buried by less-contaminated sediments. The distribution of PCBs in sediments is affected by such factors as continuing use and disposal of PCBs; leaching from disposal sites; resuspension by turbulence; redeposition (hydrodynamic forces); chemical changes; and physical and biological mixing of the sediment. The different physical and chemical properties of the individual congeners determine their behavior during those various dynamic processes.

PCBs are considered to exist in three phases in the sediment and overlying water: freely dissolved, associated with dissolved organic carbon (DOC), and sorbed to particles. PCBs sorbed to particles are subject to settling, resuspension, and burial. Particles suspended in the water column are affected by hydrodynamic conditions. PCBs that are freely dissolved or associated with DOC can cross the sediment-water interface and move between the deeper sediments (below the bioturbation or bioactive surface sediment) and the surface sediment. This movement is largely a function of diffusion between the sediment pore water, and the overlying water column. It is dependent on the detailed hydrodynamic structure at the water-sediment interface and can be greatly enhanced by bioturbation caused by organisms living in the sediments.

Generally, the less-chlorinated congeners are more water soluble, more volatile, and more likely to biodegrade. Therefore, lower concentrations of these congeners are found in sediments compared with the original concentrations of Aroclors that entered the environment. Higher-chlorinated PCBs are often more resistant to degradation and volatilization and sorb more strongly to particulate matter. Some of these more-chlorinated PCBs tend to bioaccumulate to greater concentrations in tissues of animals than do lower-molecular-weight PCBs. The more-chlorinated PCBs can also biomagnify in food webs and other higher-molecular-weight congeners have specific structures that make them susceptible to metabolism by enzymes once these congeners are taken up by such species as fish, crustacea, birds, and mammals.

The above was taken directly from National Research Council (2001)

PCBs section of Contaminant Focus

Fate and Transport of Planar and Mono-Ortho Polychlorinated Biphenyls and Polychlorinated Naphthalenes in Southern California Sediments
Venkatesan, M.I.

Distribution and Dynamics of PCBs in the Environment in a Risk Management Strategy for PCB-Contaminated Sediments
National Research Council
National Academy of Sciences 452 pp, 2001

This section of the report provides a discussion of the factors influencing the fate and transport of PCBs in the environment.

Polychlorinated biphenyl contamination trends in Lake Hartwell, South Carolina (USA): Sediment recovery profiles spanning two decades
Sivey, J.D. and C.M. Lee
Chemosphere 66 (2007) p1821�1828

This article discusses PCB biodegradation processes in Lake Hartwell sediment.

Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons form a family of compounds, and the routes of degradation and fates are different for the major classes of PAHs. The most important degradative processes for PAHs in aquatic environments are photo-oxidation, chemical oxidation, and biological transformation by bacteria and animals.

The lower molecular weight aromatics (benzene to phenanthrene) are removed primarily by evaporation and microbial activity. Higher molecular weight PAHs are removed mainly by sedimentation and photo-oxidation. Degradation of PAHs by animals in the water column is of minor importance. In nutrient rich, biologically active, aerobic sediments, the degradation of PAHs is dramatically increased by healthy bacterial and fungal communities. However, in anaerobic sediments, the heavier molecular weight PAHs (four through seven rings) may persist for years.

Adapted directly from Brooks, 2004

Anaerobic Biotransformation of Aromatic and Polycyclic Aromatic Hydrocarbons in Soil Microcosms: a Review
Karthikeyan, R. and A. Bhandari
Journal of Hazardous Substance Research, Kansas State University, 19 pp, 2001

Desorption Kinetics for Field-Aged Polycyclic Aromatic Hydrocarbons from Sediments
Shor, L., K. Rockne, G. Taghon, L. Young, and D. Kosson
Environ. Sci. Technol. 2003, 37,1535-1544

Phenanthrene Adsorption and Desorption by Melanoidins and Marine Sediment Humic Acids
Terschak, John A., Susan M. Henrichs, and David G. Shaw
Alaska Mineral Management Services, OCS Study MMS 2004-001, 71 pp, 2004

Phenanthrene Adsorption and Desorption by Melanoidins and Marine Sediment Humic Acids
Terschak, John A., Susan M. Henrichs, and David G. Shaw
Alaska Mineral Management Services, OCS Study MMS 2004-001, 71 pp, 2004

Polycyclic Aromatic Hydrocarbon Migration from Creosote-Treated Railway Ties into Ballast and Adjacent Wetlands
Brooks, K.M.
USDA, Forest Service, Research Paper FPL?RP?617, 57 pp, 2004

This study is a report on PAH level testing done in a simulated wetland mesocosm. Both newly treated and weathered creosote-treated railroad ties were placed in the simulated wetland. As a control, untreated ties were also placed in the mesocosm. Samples were taken of the ballast, wetland sediments, groundwater, stormwater, and soil cores.

Soot Deposition in the Great Lakes: Implications for Semi-Volatile Hydrophobic Organic Pollutant Deposition
Buckley, D., K. Rockne, A. Li, and W. Mills
Environ. Sci. Technol. 2004, 38,1732-1739

Toxicological Exposure of Sediment-Bound Hydrophobic Organic Contaminants as a Function of the Quality of Sediment Organic Carbon and Microbial Degradation
Fredrickson, H.L., J.W. Talley, J.S. Furey, and S. Nicholl
U.S. Army Corps of Engineers, Long Term Effects of Dredging Operations Program, ERDC/TN EEDP-04-34, 17 pp, 2003

This paper contains, in part, a general discussion of the fate of PAHs relative to the types of sediments and organic carbons in which they are found.

Case Studies

Bench-Scale Evaluation of Gas Ebullition on the Release of Contaminants from Sediments
Chattopadhyay, S., V. Lal, and E. Foote, Battelle, Columbus, OH.
EPA 600-R-10-062, 71 pp, 2010

The release of gas bubbles (ebullition) of methane and carbon dioxide from contaminated sediments can contribute to the release of PAHs and PCBs from the sediment-water interface into the water column. This report describes the results of microcosm and bench-scale column studies conducted to quantify the release of these contaminants from capped and uncapped sediments taken from Eagle Harbor and Lake Hartwell. Gas ebullition through the sediment bed was simulated at different temperatures by sparging mixed anaerobic gas at two flow rates (6.5 and 18.5 mL/min).

Pathway Ranking for In-Place Sediment Management Executive Summary
DoD, Strategic Environmental Research and Development Program
Report CU1209, 1,053 pp, 2006

The objective of this study was to provide an understanding of the relative importance of critical contaminant transport pathways in the risk, fate, and management of near-shore, in-place contaminated (PAHs and metals) sediments via: 1) an integrated suite of measurement techniques to characterize and quantify important transport pathways for in-place sediments, 2) a corresponding set of indices that quantify the transport phenomenon on a common dimensional scale, and 3) field-scale evaluation of the effectiveness of the measurement tools and the importance of quantified transport pathways. This report concerns activities at Paleta Creek, San Diego Bay.

Pathway Ranking for In-place Sediment Management, Final Site II Report — Pearl Harbor
DoD, Strategic Environmental Research and Development Program, Report CU1209, 857 pp, 2006

The objective of this study was to provide an understanding of the relative importance of critical contaminant transport pathways in the risk, fate, and management of near-shore, in-place contaminated (PAHs and metals) sediments via: 1) an integrated suite of measurement techniques to characterize and quantify important transport pathways for in-place sediments, 2) a corresponding set of indices that quantify the transport phenomenon on a common dimensional scale, and 3) field-scale evaluation of the effectiveness of the measurement tools and the importance of quantified transport pathways.

Pathway Ranking for In-Place Sediment Management, Volume III: Cross-Site Comparisons
DoD, Strategic Environmental Research and Development Program, Report CU1209, 78 pp, 2006

This final volume summarizes and compares the main results of the field efforts at Pearl Harbor and Paleta Creek, and critically analyzes their implications for pathway analysis and ranking as a future tool in contaminated sediment management.

Processes Influencing the Transport and Fate of Contaminated Sediments in the Coastal Ocean�Boston Harbor and Massachusetts Bay
Bothner, M.H., and B. Butman (eds.)
U.S. Geological Survey Circular 1302, 89 pp, 2007

Models

This section provides resources on sediment transport/surface water modeling and Web sites where models can be downloaded.

Reports & Papers

These discussions on sediment modeling do not include the model itself.

Application of Surface Complexation Modeling to Selected Radionuclides and Aquifer Sediments
Davis, J.A.
NUREG/CR-6959, 132 pp, 2008

Generalized composite/surface complexation models (GC-SCMs) were developed for 3 very different contaminant/sediment combinations: neptunium(V) in Naturita aquifer sediment, uranium(VI) in Forty Mile Wash aquifer sediment, and nickel in Cape Cod aquifer sediment. The models provided good agreement with experimental data and performed satisfactorily in describing adsorption as a function of changing chemical conditions. This approach is a compromise between the simple constant-Kd approach and more complex SCM.

EFDC1D - A One Dimensional Hydrodynamic and Sediment Transport Model for River and Stream Networks: Model Theory and Users Guide
Hamrick, J.M.
USEPA, EPA/600/R-01/073, 98 pp, 2001

Development of Sediment Prisms in Lower Fox River OU1
Eykholt, G.R., S.G. Lehrke, and D.M. Roznowski,
Foth & Van Dyke, 24 pp, 2004.

This white paper describes the rationale and approach for use of a sediment modeling tool, GMS (Environmental Modeling Systems, Inc.), to delineate the lateral and vertical extent of PCB contaminated sediment deposits in Little Lake Butte des Morts, Lower Fox River, Wisconsin.

Evaluation of Sediment Transport Models and Comparative Application of Two Watershed Models
Kalin, L. and M.M. Hantush
USEPA, Office of Research and Development
EPA/600/R-03/139, 81 pp, 2003

This report provides an overview and evaluation of sediment models and compares two distributed, watershed-scale models that were applied to an experimental watershed. A probabilistic, risk-based mathematical optimization framework is presented and proposed as a strategy, especially when multiple stressors are involved, for obtaining cost-effective, optimal load reductions using best management practices (BMPs).

The first part of the report evaluates and summarizes the key features of the most widely cited watershed-scale, hydrodynamic, and water quality models with the emphasis on total maximum daily loads and BMPs. Reviewed models were selected based on minimum criteria. Water quality models, specifically those that can simulate nutrients in the environment, are also considered because transport and fate of sediments and nutrients are intimately related phenomena.

Evaluation of the State-of-the-Art Contaminated Sediment Transport and Fate Modeling System
Hayter, E.J.
USEPA Office of Research and Development, EPA/600/R-06/108, 138 pp, 2006

This research evaluated the ability of the Environmental Fluid Dynamics Code, the state-of-the-art contaminated sediment modeling system, to simulate the transport and fate of a contaminant over a period of at least 10 years. This time period was chosen since models would normally have to run over a multi-decade period to evaluate the effectiveness of various remedial measures, such as dredging, capping, dredging and capping, and monitored natural recovery (MNR), in reducing the contaminant concentrations in both the sediment and water column. The Housatonic River was chosen as the demonstration site. PCBs are the contaminant of concern.

Hydrodynamic and Sediment Transport Modeling of Deltaic Sediment Processes
Mashriqui, H.S.
Louisiana State University, Dissertation, 152 pp, 2003

Modeling of Hydrodynamic Circulation and Cohesive Sediment Transport and Prediction of Shoreline Erosion in Hartwell Lake, SC/GA
Seker-Elci, S.
Georgia Institute of Technology, Dissertation, 242 pp, 2004

Lake Hartwell is the site of an ongoing PCB monitored natural attenuation remedy that uses fresh sedimentation to cover PCB contaminated sediments.

Simulation of Flow, Sediment Transport, and Sediment Mobility of the Lower Coeur d�Alene River, Idaho
Berenbrock, C. and A.W. Tranmer
USGS, Scientific Investigations Report 2008�5093, 176 pp, 2008

This report documents the development, calibration, and results of simulations of a one-dimensional sediment-transport model and a multi-dimensional hydraulic and bed shear stress model to investigate the hydraulic, sediment transport, and sediment mobility characteristics of the lower Coeur d�Alene River in northern Idaho.

Three Dimensional Mobile Bed Dynamics for Sediment Transport Modeling
O�Neil, S.
Ohio State University, 266 pp, 2002

This dissertation describes the development of a sediment transport model and has descriptions of the mechanisms that need to be considered when evaluating sediment transport.

Web Sites

These sites provide downloadable sediment transport models.

Single Models

CONservational Channel Evolution and Pollutant Transport System (CONCEPTS) computer model
U.S. Department of Agriculture, Agricultural Research Service

This downloadable model simulates the evolution of incised streams and evaluates the long-term impact of rehabilitation measures to stabilize stream systems and reduce sediment yield. CONCEPTS simulates unsteady, one-dimensional flow, graded sediment transport, and bank-erosion processes in stream corridors. The model can predict the dynamic response of flow and sediment transport to instream hydraulic structures. It computes channel evolution by tracking bed elevation changes and channel widening. The bank erosion module accounts for basal scour and mass wasting of unstable cohesive banks. CONCEPTS simulates the transport of cohesive and cohesionless sediments, both in suspension and on the bed, and selectively by size classes.

LTFATE Cohesive Sediment Transport Model
U.S. Army Corps of Engineers
Technical Note DOER-N1, 7 pp, 1998

• LTFATE web site

The Long-Term Fate of Dredged Material (LTFATE) model is a combined local hydrodynamics and sediment transport model used to determine the long- and short-term stability of dredged material mounds. This technical note introduces a new cohesive sediment transport submodel for LTFATE that includes a combined current-wave shear stress calculation and a layered sediment bed model.

SRH-1D (Formerly GSTAR-1D)
U.S. Department of the Interior, Bureau of Reclamation

This downloadable model is a hydraulic and sediment transport numerical model developed to simulate flows in rivers and channels with or without movable boundaries.

TrophicTrace: A Tool for Assessing Risks from Trophic Transfer of Sediment-Associated Contaminants
U.S. Army Corps of Engineers

TrophicTrace is an Excel add-in that provides a spreadsheet tool for calculating the potential human health and ecological risks associated with bioaccumulation of contaminants in dredged sediments.

Multiple Models

Coastal and Hydraulics Laboratory Supported Software � Licensing and Availability Statements
U.S. Army Corps of Engineers, 17 pp, 2008

This document provides a concise description of sediment transport models developed and maintained by the Coastal and Hydraulics Laboratory. Contact information for each model is also provided.

Numerical Models for Simulating Flow and Sedimentation Processes in the Natural Environment
National Center for Computational Hydroscience and Engineering, University of Mississippi

This Web page describes models that have been developed by the University using U.S. Department of Agriculture funding. Some of the software is free with certain limitations. The models address surface water flow, and sediment and contaminant fate and transport among other things.

Water Quality Models and Tools
U.S. Corps of Engineers

This Web page lists water quality software models that are available to the general public and members of the Corps. While the emphasis is on surface water, it contains some sediment and contaminant components.

Water Resources Surface Water Software
U.S. Geological Survey

This Web page lists and describes USGS-developed models that are downloadable by the general public. While the focus of many of these models is surface water flow, some contain sediment transport elements.

Top of Page