Title: Introduction Text: This Web data sheet presents new sediment characterization methods studied by the Office of Naval Research (ONR). These methods are currently being field tested at several Navy sites. Navy remedial project managers (RPMs) can use these methods to provide evidence of biodegradation, to quantify the effects of seasonal variation, to estimate contaminant transport, and to measure background contamination in industrialized watersheds. All of these lines of evidence can be used to make defensible and cost-effective risk and remedial management decisions. In addition, the use of these new methods in the context of Navy policy and guidance for sediment site investigations is discussed. Visual Description: Aerial photo of an aircraft carrier entering the docking area from a bay.

Title: Background Text: Sediment investigations are often more complex than terrestrial investigations for a variety of reasons. These include the inherently dynamic sediment ecosystem, increased contaminant mobility, and the variety of potential sources and exposure pathways. Additionally, sediments commonly require specialized methods for sampling, analysis, and remediation. Navy RPMs responsible for sediment sites should be aware of these issues in order to make informed decisions that balance applicable regulations, risk reduction, public benefit, and costs. Question: Do you have a site with contaminated sediments? Yes, No, Not Sure Visual Description: Animated diagram of a factory (source) discharging into a river or stream. Contaminants are carried downstream and deposited with sediment resulting in contaminated sediments.

Title: Sediment Contamination Text: Major sediment contaminants are nonvolatile and insoluble compounds that persist in the environment. The U.S. EPA (1997) estimates that 6% to 12% of U.S. sediment is contaminated. In a 1993 survey of Navy facilities, 94% of the respondents reported the presence of at least one contaminant of potential concern in sediments. The most common contaminants reported at Navy sites were metals, polychlorinated biphenyls (PCBs), other hydrocarbons, pesticides, and fuels.

Title: Sediment Characterization Methods Text: The ONR has developed and field tested several new sediment site characterization methods including the following: Principal Component Analyses (PCA) Compound-Specific Stable Isotope Fingerprinting Rapid Characterization Watershed Sampling Seasonal Sampling and Source Input Organotolerance of Bacteria Lines of Evidence for Natural Recovery These new methods, if implemented as part of a comprehensive oceano-graphic sampling strategy, can help to provide a better understanding of the ecological impact at a site and the amount of contamination from Navy and non-Navy sources in an industrialized watershed. Visual Description: Photo of a person on a ship collecting samples.

Title: PCA Analyses Text: Principal component analyses (PCA) is one method for identifying or ruling out potential sources of organic contaminants. PCA uses the ratios of individual compounds within a mixture to help identify the characteristics of the potential source or sources. The Navy-supported research has focused on PCA of polycyclic aromatic hydrocarbons (PAHs), but this method may also apply to polychlorinated biphenyls (PCBs). The primary advantage of this analysis is that it can be performed on existing data sets already collected as part of a typical Navy remedial investigation (RI). Visual Description: Graphic of a PCA score plot (2-factor analysis) showing PCA factor scores vs. PC-1 factor scores to determine the dominant contaminant source (natural background, urban run-off, or creosote).

Title: Compound-Specific Stable Isotope Fingerprinting Text: This method is used for contaminant source identification and has been utilized for PAHs and trinitrotoluene (TNT) in sediments as part of the ONR research program. The method involves the measurement of the ambient concentration of individual compounds and the determination of the ratio of carbon-13 to carbon-12 for each compound. These ratios can be specific to the geographic origins of the source material, the isolation procedure, or the synthesis method. These ratios are also preserved despite biological, chemical, or physical processes acting on the compounds once released into the environment. This analysis is more expensive than standard concentration measurements for sediment, but can provide valuable information for source determinations. Visual Description: Graphs of percent t-PAH for different compounds.

Title: Rapid Characterization Text: Rapid characterization techniques have been developed to estimate PAH and PCB concentrations during an initial site survey, followed by resampling to obtain a more detailed genetic and biochemical analysis. The rapid characterization immunoassay can be performed in less than 24 hours, which allows it to be used in conjunction with a 2-day watershed sampling event. This rapid field test allows the RPM to choose more effective sample locations based on preliminary screening results, instead of waiting 2 weeks for the complete set of laboratory results. Visual Description: Photo of rapid characterization equipment.

Title: Immunoassay Text: Identification of a substance (especially a protein) by its action as an antigen.

Title: Watershed Sampling Strategy Text: Since 1997, the Naval Research Laboratory (NRL) has been testing a new strategy for selection of sediment sampling stations and determination of the number of sampling events based on an oceanographic understanding of estuary-specific processes. These considerations include hydrodynamic issues based on water flow, physical characteristics of the area surrounding the Navy sediment site, importance of seasonal fluctuations in temperature and rainfall, and distribution of sampling stations across the watershed. This strategy was applied during sampling events in the lower Chesapeake Bay, Charleston Harbor, San Francisco Bay, and the upper Delaware and Schuylkill Rivers (near Philadelphia). Click here for more information on these studies. Visual Description: Photo of a person standing on a large piece of sediment sampling equipment.

Title: Study Information Text: More information is available on the Philadelphia study as journal articles (Pohlman et al. 2002) and technical reports (Boyd et al. 1999), and the Charleston study will be published within the next year (Montgomery et al. 2003).

Title: Seasonal Sampling Strategy and Source Input Text: Most sediment sampling approaches are based on shore-side strategies and therefore do not adequately consider the effects of seasonal variation or sample location on contaminant concentration variance. An oceanographic plan calls for sampling of the same watershed stations over several seasons, as well as sampling organic contaminants bound to water column particles. Sampling the watershed seasonally for several years allows the RPM to assign ecologically relevant error bars to the measured contaminant concentration at a site. It is also important to measure the amount of contaminant bound to particles in the water column (seston), moving over the sediment tidally (nepheloid), or depositing onto the surface sediments (sediment traps). The sediment trap material may provide a more site-specific and ecologically relevant reference material than the “pristine” areas that are often chosen as reference sites in Navy RIs. These measures can also be coupled with data on water flow to estimate contaminant transport through a specific area of the watershed. Visual Description: Photo of a surface sediment grab sampling device.

Title: Organotolerance of Bacteria Text: At some sites, adjacent non-Navy facilities may contribute higher molecular-weight organics to Navy sediments. One strategy to determine the source of high molecular-weight organics is to employ a radiotracer assay that measures the response of the bacterial population to volatile organic compound (VOC) exposure. As bacteria in the sediment are repeatedly exposed to VOCs, many of them become tolerant of the presence of the chemicals. The degree of organotolerance can be directly measured by exposing subsamples of the natural bacteria to increasing amounts of a VOC. In an ONR study, the growth rate of bacteria in sediments from chronically exposed areas was not adversely affected by naphthalene addition. However, bacteria from sediments in more pristine areas were dramatically affected and their growth rate declined in the presence of napthalene. This type of assay has been applied by ONR at the Charleston Harbor, San Diego Bay, and near the Philadelphia area. Visual Description: Photo of a factory releasing pollutants into the air.

Title: Lines of Evidence for Natural Recovery Text: There is widespread recognition of the importance of measuring the intrinsic rates of contaminant biodegradation in sediments. However, there are few microbiologically valid methods currently used in Navy RIs. RPMs should document several lines of evidence to assess the potential for natural recovery at Navy sediment sites including: The genetic capacity for biodegradation; The presence of metabolic intermediates known to result from biodegradation; The change in ambient contaminant concentration in response to electron acceptor availability; and Radiotracer (e.g., 14C-PAHs) mineralization by native bacteria. The results of the ONR research have indicated that the best strategy for identifying sediment sites that are undergoing natural recovery is to first determine that the genetic capacity exists by finding in situ evidence that metabolism is occurring (e.g., presence of intermediates). The next step should be to estimate the in situ rate via radiotracer additions. Next, the estimated degradation rate or contaminant turnover time should be compared with contaminant transport rates (e.g., sediment trap data) and ambient contaminant concentration to determine if the calculated biodegradation rate is ecologically significant.

Title: NAVFAC Policy and Guidance Text: The regulatory and policy framework for sediment site investigation and cleanup can be challenging to understand because the state of the science and environmental regulations are still evolving. In the past, RIs of Navy impacted sediment typically involved sampling strategies based on those used at shore-side groundwater sites. The use of these methods is inappropriate due to the complexity of the sediment environment. The Navy has recently developed policy and guidance documents to help Navy RPMs in the completion of successful RIs at Navy sediment sites. Visual Description: Photo of a Navy ship near the USS Arizona Memorial in Pearl Harbor

Title: Overview of Navy Policy on Sediment Investigations Text: In February 2002, the Chief of Naval Operations (CNO) released a policy of sediment site investigation and response action that may provide a framework for applying some or all of the methods discussed. The policy is summarized below. The table to the left identifies each method being developed and the following policy statements to which it corresponds: (1) All sources shall be identified to determine if the Navy is solely responsible for the contamination. (2) All investigations shall primarily be linked to a specific Navy CERCLA/RCRA site. (3) All sediment investigations and response actions shall be consistent with Navy policies on risk assessment and background chemical levels. (4) Sediment cleanup goals shall be developed based on site-specific information and shall be risk-based. (5) The Navy shall not clean up contamination from a non-Navy source where the Navy has not contributed to the risk in sediments. The Navy will not clean up a site before the source is contained. Any potential recontamination by non-Navy sources shall be documented. (6) A monitoring plan with exit strategies shall be developed before collecting the first monitoring sample. Visual Description: Table of methods and their corresponding CNO policy statements.

Title: NAVFAC's Implementation Guide Text: Another key document is the Naval Facilities Engineering Command (NAVFAC) "Implementation Guide for Assessing and Managing Contaminated Sediments at Navy Facilities" (2003). This document contains practical guidelines for conducting sediment site assessments and remedial alternative evaluations at Navy sites. The NAVFAC implementation guide complements the CNO sediment policy, as well as other applicable policies and guidance on risk assessment and the use of background chemical levels. Click here for more information. Visual Description: Picture of NAVFAC's Implementation Guide for Assessing and Monitoring Contaminated Sediments at Navy Sites.

Title: Navy Sediment Guide Text: The document is intended to help RPMs avoid unnecessary studies and to coordinate and integrate data collection activities across all aspects of the sediment investigation. Specifically, the guide identifies and discusses sediment-specific issues related to: Site characterization Risk assessment Remedial alternative evaluation. The site characterization section presents an overview of sediment investigations, including planning considerations, developing a conceptual site model (CSM), identifying sources, defining the nature and extent of contamination, and characterizing contaminant fate and transport. It also identifies important physical and chemical data that should be collected as part of a sediment investigation, with an emphasis on coordinating data collection for all aspects of the investigation. The risk assessment section presents step-by-step procedures for conducting ecological and human health risk assessment at sediment sites within the Navy's tiered framework. Elements within the framework that are unique to sediment investigations are identified. The remedial action section addresses planning considerations and determination of site-specific risk-based cleanup levels. Remedial options, including monitored natural recovery, in situ capping, and removal, are described along with monitoring considerations and sediment management issues.

Title: Summary Text: Sediment investigations should employ oceanographic sampling strategies and methods if they are to provide information that is ecologically significant and useful in understanding the relevance of contaminants on Navy property relative to the rest of the industrialized watershed. The methods discussed above combine measures of transport and biodegradation with a seasonal and watershed-level sampling approach and can provide an RPM with defensible evidence to make cost-effective sediment management decisions. Question: How much did this tool increase your awareness of innovative sediment characterization techniques? Minimally, Moderately, Greatly Visual Description: Photo of sediment sampling equipment on a ship.

Title: References Text: United States Environmental Protection Agency (U.S. EPA). 1997. "The Incidence and Severity of Sediment Contamination in Surface Waters of the United States, Vol. 1: National Sediment Quality Survey." U.S. Navy Chief of Naval Operations (CNO). 2002. Policy on Sediment Site Investigation and Response Action. Naval Facilities Engineering Command (NAVFAC). 2003. Implementation Guide For Assessing and Managing Contaminated Sediment at Navy Facilities. Naval Facilities Engineering Command (NAVFAC). May 2003. Accelerated Implementation of Harbor Processes Research.

Title: Contact Text: For more information about the ONR-supported programs related to sediment site characterization, please contact: PRTH_NFESCT2@navy.mil