Techniques for enumerating protozoa in saturated subsurface sediments

Three techniques were investigated for the enumeration of small (2-5 $\mu$m in diameter) flagellates and amoebae in sediments collected within and outside of a wastewater contaminated ground water plume at the U.S. Geological Survey Toxic Substances Hydrology Research site, located on Cape Cod, MA. An epifluorescent direct count technique was developed to enumerate DAPI stained protozoa on polycarbonate membrane filters. These estimates were compared to the those from the Darbyshire liquid media MPN and Singh solid media MPN techniques. In Fall 1991, sediment samples were collected to investigated the variability of the hold time of cores, total and encysted protozoan populations (MPN techniques only), and sites. The population estimates changed significantly (with 95% confidence) from 1 to 28 days hold time: 1.22 $\times$ 10\sp4 to 7.71 $\times$ 10\sp3 protozoa/gdw for the epifluorescent technique; 2.94 $\times$ 10\sp4 to 3.82 $\times$ 10\sp4 total MPN/gdw for the Darbyshire MPN technique; and 6.85 $\times$ 10\sp2 to 1.74 $\times$ 10\sp5 total MPN/gdw for the Singh MPN technique. The epifluorescent technique had the lowest variability of all techniques. The encysted population did not exceed 42% of the total population by either MPN technique. Protozoan populations by all enumeration techniques were significantly higher from three cores at a contaminated site compared to those from three cores at an uncontaminated site. The largest source of variation for the protozoan estimates was the cores for the epifluorescent and Darbyshire MPN techniques and the subsamples within the cores for the Singh MPN technique. The maximum probable error calculated for each enumeration technique based on the components from the sampling of the contaminated site were: 6.07 $\times$ 10\sp3 protozoa/gdw for the epifluorescent technique; 5.56 $\times$ 10\sp4 total MPN/gdw for the Darbyshire MPN technique; and 5.86 $\times$ 10\sp4 total MPN/gdw for the Singh MPN technique. The changes over the hold time were within the detectable difference for the epifluorescent and Darbyshire MPN techniques. However, the significant increase in the Singh MPN estimates over time was not explained by the errors in the sampling technique and should be further investigated

Deep Vadose Zone?Applied Field Research Initiative Fiscal Year 2012 Annual Report

This annual report describes the background of the Deep Vadose Zone-Applied Field Research Initiative, and some of the programmatic approaches and transformational technologies in groundwater and deep vadose zone remediation developed during fiscal year 2012

Current Conditions Risk Assessment for the 300-FF-5 Groundwater Operable Unit

This report updates a baseline risk assessment for the 300 Area prepared in 1994. The update includes consideration of changes in contaminants of interest and in the environment that have occurred during the period of interim remedial action, i.e., 1996 to the present, as well as the sub-regions, for which no initial risk assessments have been conducted. In 1996, a record of decision (ROD) stipulated interim remedial action for groundwater affected by releases from 300 Area sources, as follows: (a) continued monitoring of groundwater that is contaminated above health-based levels to ensure that concentrations continue to decrease, and (b) institutional controls to ensure that groundwater use is restricted to prevent unacceptable exposure to groundwater contamination. In 2000, the groundwater beneath the two outlying sub-regions was added to the operable unit. In 2001, the first 5-year review of the ROD found that the interim remedy and remedial action objectives were still appropriate, although the review called for additional characterization activities. This report includes a current conditions baseline ecological and human health risk assessment using maximum concentrations in the environmental media of the 300-FF-5 Operable Unit and downstream conditions at the City of Richland, Washington. The scope for this assessment includes only current measured environmental concentrations and current use scenarios. Future environmental concentrations and future land uses are not considered in this assessment

Uranium in the Near-shore Aquatic Food Chain: Studies on Periphyton and Asian Clams

The benthic aquatic organisms in the near-shore environment of the Columbia River are the first biological receptors that can be exposed to groundwater contaminants coming from the U.S. Department of Energy's Hanford Site. The primary contaminant of concern in the former nuclear fuels processing area at the Site, known as the 300 Area, is uranium. Currently, there are no national clean up criteria for uranium and ecological receptors. This report summarizes efforts to characterize biological uptake of uranium in the food chain of the benthic aquatic organisms and provide information to be used in future assessments of uranium and the ecosystem

Summary of TPH Monitoring Conducted at 100-NR-2- 2008 through 2010

A summary of TPH monitoring conducted along the 100-N shoreline and the 100-NR-2 operable uni

Investigation of the Hyporheic Zone at the 300 Area,Hanford Site

The Remediation Task of the Science and Technology (S&T) Project is intended to provide research to meet several objectives concerning the discharge of groundwater contamination into the river at the 300 Area of the Hanford Site. This report serves to meet the research objectives by developing baseline data for future evaluation of remedial technologies, evaluating the effects changing river stage on near-shore groundwater chemistry, improving estimates of contaminant flux to the river, providing estimates on the extent of contaminant discharge areas along the shoreline, and providing data to support computer models used to evaluate remedial alternatives. This report summarizes the activities conducted to date and provides an overview of data collected through July 2006. Recent geologic investigations (funded through other U. S. Department of Energy (DOE) programs) have provided a more complete geologic interpretation of the 300 Area and a characterization of the vertical extent of uranium contamination. Extrapolation of this geologic interpretation into the hyporheic zone is possible, but there is little data to provide corroboration. Penetration testing was conducted along the shoreline to develop evidence to support the extrapolation of the mapping of the geologic facies. In general, this penetration testing provided evidence supporting the extrapolation of the most recent geologic interpretation, but it also provided some higher resolution detail on the shape of the layer than constrains contaminant movement. Information on this confining layer will provide a more detailed estimate of the area of river bed that has the potential to be impacted by uranium discharge to the river from groundwater transport. Water sampling in the hyporheic zone has provided results that illustrate the degree of mixing that occurs in the hyporheic zone. Uranium concentrations measured at individual sampling locations can vary by several orders of magnitude depending on the river and near-shore aquifer elevations. It is shown in this report that the concentrations of all the measured constituents in water samples collected from the hyporheic zone vary according to the ratio of groundwater and river water in the sample. One important aspect of this is that specific conductance provides a sensitive indicator of the relative contribution of groundwater and river water in a particular sample. This is because of the large difference is specific conductance of groundwater (~400 μS/cm) and river water (~130 μS/cm). It appears that in the hyporheic zone, advection of contaminates occurs very quickly, and variations in concentrations are a function of dilution rather than any chemistry effects caused by the difference in water chemistry between groundwater and river water

Hanford Site National Environmental Policy Act (NEPA) Characterization

This document describes the U.S. Department of Energy's (DOE) Hanford Site environment. It is updated each year and is intended to provide a consistent description of the Hanford Site environment for the many National Environmental Policy Act (NEPA) documents being prepared by DOE contractors. No statements of significance or environmental consequences are provided. This year's report is the thirteenth revision of the original document published in 1988 and is (until replaced by the fourteenth revision) the only version that is relevant for use in the preparation of Hanford NEPA, State Environmental Policy Act (SEPA), and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) documents. The two chapters included in this document (Chapters 4 and 6) are numbered to correspond to the chapters where such information is typically presented in environmental impact statements (Weiss) and other Hanford Site NEPA or CERCLA documentation. Chapter 4.0 (Affected Environment) describes Hanford Site climate and meteorology, geology, hydrology, ecology, cultural, archaeological, and historical resources, socioeconomics, occupational safety, and noise. Chapter 6.0 (Statutory and Regulatory Requirements) describes federal and state laws and regulations, DOE directives and permits, and presidential executive orders that are applicable to the NEPA documents prepared for Hanford Site activities

Scientific Opportunities for Monitoring at Environmental Remediation Sites (SOMERS): Integrated Systems-Based Approaches to Monitoring

Through an inter-disciplinary effort, DOE is addressing a need to advance monitoring approaches from sole reliance on cost- and labor-intensive point-source monitoring to integrated systems-based approaches such as flux-based approaches and the use of early indicator parameters. Key objectives include identifying current scientific, technical and implementation opportunities and challenges, prioritizing science and technology strategies to meet current needs within the DOE complex for the most challenging environments, and developing an integrated and risk-informed monitoring framework

Scientific Opportunities for Monitoring of Environmental Remediation Sites (SOMERS) - 12224

ABSTRACT The US Department of Energy (DOE) is responsible for risk reduction and cleanup of its nuclear weapons complex. DOE maintains the largest cleanup program in the world, currently spanning over a million acres in 13 states. The inventory of contaminated materials includes 90 million gallons of radioactive waste, 6.4 trillion liters of groundwater, and 40 million cubic meters of soil and debris. It is not feasible to completely restore many sites to predisposal conditions. Any contamination left in place will require monitoring, engineering controls and/or land use restrictions to protect human health and environment. Research and development efforts to date have focused on improving characterization and remediation. Yet, monitoring will result in the largest life-cycle costs and will be critical to improving performance and protection. Through an inter-disciplinary effort, DOE is addressing a need to advance monitoring approaches from sole reliance on cost-and labor-intensive point-source monitoring to integrated systems-based approaches such as flux-based approaches and the use of early indicator parameters. Key objectives include identifying current scientific, technical and implementation opportunities and challenges, prioritizing science and technology strategies to meet current needs within the DOE complex for the most challenging environments, and developing an integrated and risk-informed monitoring framework

Deep Vadose Zone–Applied Field Research Initiative Fiscal Year 2012 Annual Report

This annual report describes the background of the Deep Vadose Zone-Applied Field Research Initiative, and some of the programmatic approaches and transformational technologies in groundwater and deep vadose zone remediation developed during fiscal year 2012