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Sample records for contaminated hanford sediments

  1. Uranium Phases in Contaminated Sediments Below Hanford's U Tank Farm

    SciTech Connect

    Um, Wooyong; Wang, Zheming; Serne, R. Jeffrey; Williams, Benjamin D.; Brown, Christopher F.; Dodge, Cleveland J.; FRANCIS, AROKIASAMY J.

    2009-06-11

    Macroscopic and spectroscopic investigations (XAFS, XRF and TRLIF) on Hanford contaminated vadose zone sediments from the U-tank farm showed that U(VI) exists as different surface phases as a function of depth below ground surface (bgs). Dominant U(VI) silicate precipitates (boltwoodite and uranophane) were present in shallow-depth sediments (15-16 m bgs). In the intermediate depth sediments (20-25 m bgs), adsorbed U(VI) phases dominated but small amounts of surface precipitates consisting of polynuclear U(VI) surface complex were also identified. The deep depth sediments (> 28 m bgs) showed no signs of contact with tank wastes containing Hanford-derived U(VI), but natural uranium solid phases were observed. Most of the U(VI) was preferentially associated with the silt and clay size fractions and showed strong correlation with Ca, especially for the precipitated U(VI) silicate phase in the shallow depth sediments. Because U(VI) silicate precipitates dominate the U(VI) phases in the shallow depth sediments, macroscopic (bi)carbonate leaching should result in U(VI) releases from both desorption and dissolution processes. Having several different U(VI) surface phases in the Hanford contaminated sediments indicates that the U(VI) release mechanism could be complicated and that detailed characterization of the sediments would be needed to estimate U(VI) fate and transport in vadose zone.

  2. Advective Desorption of Uranium (VI) from Contaminated Hanford Vadose Zone Sediments under Saturated and Unsaturated Conditions

    SciTech Connect

    Wellman, Dawn M.; Zachara, John M.; Liu, Chongxuan; Qafoku, Nikolla; Smith, Steven C.; Forrester, Steven W.

    2008-11-03

    Sedimentary, hydrologic, and geochemical variations in the Hanford subsurface environment, as well as compositional differences in contaminating waste streams, have created vast differences in the migration and mobility of uranium within the subsurface environment. A series of hydraulically-saturated and -unsaturated column experiments were performed to i.) assess the effect of water content on the advective desorption and migration of uranium from contaminated sediments, and ii.) evaluate the uranium concentration that can develop in porewater and/or groundwater as a result of desorption/dissolution reactions. Flow rate and moisture content were varied to evaluate the influence of contact time, pore water velocity, and macropore desaturation on aqueous uranium concentrations. Sediments were collected from the T-TX-TY tank farm complex and the 300 Area Process Ponds located on the Hanford Site, southeastern Washington State. The sediments vary in depth, mineralogy, and in contamination events. Experiments were conducted under mildly alkaline/calcareous conditions representative of conditions commonly encountered at repository sites across the arid western United States and, in particular, the Hanford site. Results illustrate the release of uranium from these sediments is kinetically controlled and low water contents encountered within the Hanford vadose zone result in the formation of mobile-immobile water regimes, which isolate a fraction of the reactive sites within the sediments, effectively reducing the concentration of uranium released into migrating porewaters.

  3. Contaminant desorption during long-term leaching of hydroxide-weathered Hanford sediments

    SciTech Connect

    Thompson, A.; Steefel, C.I.; Perdrial, N.; Chorover, J.

    2009-11-01

    Considerable efforts have been made toward understanding the behavior of contaminants introduced into sediments surrounding high-level radioactive waste (HLRW) storage sites at several Department of Energy (DOE) facilities (Hanford Site, WA; Savannah River Site, SC; Oak Ridge Site, TN).

  4. Bench-scale electrokinetic remediation for cesium-contaminated sediment at the Hanford Site, USA

    SciTech Connect

    Jung, Hun Bok; Yang, Jungseok; Um, Wooyong

    2015-05-01

    Electrokinetic (EK) remediation has been applied to extract various contaminants such as radionuclides, heavy metals, and organic compounds from contaminated sediment and soil using electric currents. We conducted a laboratory experiment to investigate the efficiency of EK remediation method for Hanford sediment (76% sand and 24% silt-clay) after artificial contamination with nonradioactive 133Cs (0.01 M CsNO3) as a surrogate for radioactive 137Cs. The initial 133Cs concentration in the bulk sediment was 668 mg kg-1, with a higher 133Cs concentration for the silt-clay fraction (867 mg kg-1) than for the sand fraction (83 mg kg-1). A significant removal of cationic 133Cs from the sediment occurred from the cathode side (-), whereas the removal was negligible from the anode side (+) during the EK remediation process for 68 days. Based on microwave-assisted total digestion, 312 mg kg-1 of 133Cs was removed from the bulk sediment, which corresponds to the removal efficiency of 47%. The EK method was significantly more efficient for the silt-clay fraction than for the sand fraction. X-ray diffraction (XRD) and scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS) analyses indicate that change in major crystalline mineral phases was insignificant during the EK remediation and the removal of 133Cs from the Hanford sediment by the EK method is attributed mainly to cation exchange with K in clay minerals. The experimental results suggest that the EK method can effectively remove radioactive Cs from the surface or subsurface sediment contaminated by radioactive materials in the Hanford Site, Washington, USA.

  5. Trace contaminant concentration affects mineral transformation and pollutant fate in hydroxide-weathered Hanford sediments.

    PubMed

    Perdrial, Nicolas; Rivera, Nelson; Thompson, Aaron; O'Day, Peggy A; Chorover, Jon

    2011-12-15

    Prior work has shown that when silicaceous sediments are infused with caustic radioactive waste, contaminant fate is tightly coupled to ensuing mineral weathering reactions. However, the effects of local aqueous geochemical conditions on these reactions are poorly studied. Thus, we varied contaminant concentration and pCO(2) during the weathering of previously uncontaminated Hanford sediments over 6 months and 1 year in a solution of caustic waste (pH 13, high ionic strength). Co-contaminants Sr, Cs and I were added at "low" (Cs/Sr: 10(-5)m; I: 10(-7)m) and "high" (Cs/Sr: 10(-3)m; I: 10(-5)m) concentrations, and headspace was held at atmospheric or undetectable (<10ppmv) CO(2) partial pressure. Solid phase characterization revealed the formation of the zeolite chabazite in "high" samples, whereas feldspathoids, sodalite and cancrinite, were formed preferentially in "low" samples. Sr, Cs and I were sequestered in all reacted sediments. Native calcite dissolution in the CO(2)-free treatment drove the formation of strätlingite (Ca(2)Al(2)SiO(7)·8H(2)O) and diminished availability of Si and Al for feldspathoid formation. Results indicate that pCO(2) and contaminant concentrations strongly affect contaminant speciation in waste-weathered sediments, and are therefore likely to impact reaction product stability under any remediation scenario.

  6. Transuranic Contamination in Sediment and Groundwater at the U.S. DOE Hanford Site

    SciTech Connect

    Cantrell, Kirk J.

    2009-08-20

    A review of transuranic radionuclide contamination in sediments and groundwater at the DOE’s Hanford Site was conducted. The review focused primarily on plutonium-239/240 and americium-241; however, other transuranic nuclides were discussed as well, including neptunium-237, plutonium-238, and plutonium-241. The scope of the review included liquid process wastes intentionally disposed to constructed waste disposal facilities such as trenches and cribs, burial grounds, and unplanned releases to the ground surface. The review did not include liquid wastes disposed to tanks or solid wastes disposed to burial grounds. It is estimated that over 11,800 Ci of plutonium-239, 28,700 Ci of americium-241, and 55 Ci of neptunium-237 have been disposed as liquid waste to the near surface environment at the Hanford Site. Despite the very large quantities of transuranic contaminants disposed to the vadose zone at Hanford, only minuscule amounts have entered the groundwater. Currently, no wells onsite exceed the DOE derived concentration guide for plutonium-239/240 (30 pCi/L) or any other transuranic contaminant in filtered samples. The DOE derived concentration guide was exceeded by a small fraction in unfiltered samples from one well (299-E28-23) in recent years (35.4 and 40.4 pCi/L in FY 2006). The primary reason that disposal of these large quantities of transuranic radionuclides directly to the vadose zone at the Hanford Site has not resulted in widespread groundwater contamination is that under the typical oxidizing and neutral to slightly alkaline pH conditions of the Hanford vadose zone, transuranic radionuclides (plutonium and americium in particular) have a very low solubility and high affinity for surface adsorption to mineral surfaces common within the Hanford vadose zone. Other important factors are the fact that the vadose zone is typically very thick (hundreds of feet) and the net infiltration rate is very low due to the desert climate. In some cases where

  7. Geomicrobiology of High Level Nuclear Waste-Contaminated Vadose Sediments at the Hanford Site, Washington State

    SciTech Connect

    Fredrickson, Jim K.; Zachara, John M.; Balkwill, David L.; Kennedy, David W.; Li, Shu-Mei W.; Kostandarithes, Heather M.; Daly, Michael J.; Romine, Margaret F.; Brockman, Fred J.

    2004-07-07

    Sediments from a high-level nuclear waste plume were collected as part of investigations to evaluate the potential fate and migration of contaminants in the subsurface. The plume originated from a leak that occurred in 1962 from a waste tank consisting of high concentrations of alkali, nitrate, aluminate, Cr(VI), 137Cs, and 99Tc. Investigations were initiated to determine the distribution of viable microorganisms in the vadose sediment samples, probe the phylogeny of cultivated and uncultivated members, and evaluate the ability of the cultivated organisms to survive acute doses of ionizing radiation. The populations of viable aerobic heterotrophic bacteria were generally low, from below detection to {approx}104 7 CFU g-1 but viable microorganisms were recovered from 11 of 16 samples including several of the most radioactive ones (e.g., > 10 ?Ci/g 137Cs). The isolates from the contaminated sediments and clone libraries from sediment DNA extracts were dominated by members related to known Gram-positive bacteria. Gram-positive bacteria most closely related to Arthrobacter species were the most common isolates among all samples but other high G+C phyla were also represented including Rhodococcus and Nocardia. Two isolates from the second most radioactive sample (>20 ?Ci 137Cs g-1) were closely related to Deinococcus radiodurans and were able to survive acute doses of ionizing radiation approaching 20kGy. Many of the Gram-positive isolates were resistant to lower levels of gamma radiation. These results demonstrate that Gram-positive bacteria, predominantly high G+C phyla, are indigenous to Hanford vadose sediments and some are effective at surviving the extreme physical and chemical stress associated with radioactive waste.

  8. Influence of Contact Time on the Extraction of 233Uranyl Spike and Contaminant Uranium From Hanford Sediment

    SciTech Connect

    Smith, Steven C.; Szecsody, James E.

    2011-11-01

    In this study 233Uranyl nitrate was added to uranium (U) contaminated Hanford 300 Area sediment and incubated under moist conditions for 1 year. It hypothesized that geochemical transformations and/or physical processes will result in decreased extractability of 233U as the incubation period increases, and eventually the extraction behavior of the 233U spike will be congruent to contaminant U that has been associated with sediment for decades. Following 1 week, 1 month, and 1 year incubation periods, sediment extractions were performed using either batch or dynamic (sediment column flow) chemical extraction techniques. Overall, extraction of U from sediment using batch extraction was less complicated to conduct compared to dynamic extraction, but dynamic extraction could distinguish the range of U forms associated with sediment which are eluted at different times.

  9. Mineral transformation controls speciation and pore-fluid transmission of contaminants in waste-weathered Hanford sediments

    NASA Astrophysics Data System (ADS)

    Perdrial, Nicolas; Thompson, Aaron; O'Day, Peggy A.; Steefel, Carl I.; Chorover, Jon

    2014-09-01

    Portions of the Hanford Site (WA, USA) vadose zone were subjected to weathering by caustic solutions during documented releases of high level radioactive waste (containing Sr, Cs and I) from leaking underground storage tanks. Previous studies have shown that waste-sediment interactions can promote variable incorporation of contaminants into neo-formed mineral products (including feldspathoids and zeolites), but processes regulating the subsequent contaminant release from these phases into infiltrating background pore waters remain poorly known. In this paper, reactive transport experiments were conducted with Hanford sediments previously weathered for one year in simulated hyper-alkaline waste solutions containing high or low 88Sr, 127I, and 133Cs concentrations, with or without CO2(aq). These waste-weathered sediments were leached in flow-through column experiments with simulated background pore water (characteristic of meteoric recharge) to measure contaminant release from solids formed during waste-sediment interaction. Contaminant sorption-desorption kinetics and mineral transformation reactions were both monitored using continuous-flow and wet-dry cycling regimes for ca. 300 pore volumes. Less than 20% of contaminant 133Cs and 88Sr mass and less than 40% 127I mass were released over the course of the experiment. To elucidate molecular processes limiting contaminant release, reacted sediments were studied with micro- (TEM and XRD) and molecular- (Sr K-edge EXAFS) scale methods. Contaminant dynamics in column experiments were principally controlled by rapid dissolution of labile solids and competitive exchange reactions. In initially feldspathoidic systems, time-dependent changes in the local zeolitic bonding environment observed with X-ray diffraction and EXAFS are responsible for limiting contaminant release. Linear combination fits and shell-by-shell analysis of Sr K-edge EXAFS data revealed modification in Sr-Si/Al distances within the zeolite cage. Wet

  10. Carbon Tetrachloride and Chloroform Partition Coefficients Derived from Aqueous Desorption of Contaminated Hanford Sediments

    SciTech Connect

    Riley, Robert G.; Sklarew, Debbie S.; Brown, Christopher F.; Gent, Philip M.; Szecsody, Jim E.; Mitroshkov, Alexandre V.; Thompson, Christopher J.

    2005-07-08

    Researchers at PNNL determined CCl4 and CHCl3 groundwater/sediment partition coefficients (Kd values) for contaminated aquifer sediments collected from borehole C3246 (299-W15-46) located in the 200 West Area adjacent to the Z-9 trench. Having realistic values for this parameter is critical to predict future movement of CCl4 in groundwater from the 200 West Area.

  11. Survey of Potential Hanford Site Contaminants in the Upper Sediment for the Reservoirs at McNary, John Day, The Dalles, and Bonneville Dams, 2003

    SciTech Connect

    Patton, Gregory W.; Priddy, M; Yokel, Jerel W.; Delistraty, Damon A.; Stoops, Thomas M.

    2005-02-01

    This report presents the results from a multi-agency cooperative environmental surveillance study. of the study looked at sediment from the pools upstream from dams on the Columbia River that are downstream from Hanford Site operations. The radiological and chemical conditions existing in the upper-level sediment found in the pools upstream from McNary Dam, John Day Dam, The Dalles Lock and Dam, and Bonneville Dam were evaluated. This study also evaluated beach sediment where available. Water samples were collected at McNary Dam to further evaluate potential Hanford contaminants in the lower Columbia River. Samples were analyzed for radionuclides, chemicals, and physical parameters. Results from this study were compared to background values from sediment and water samples collect from the pool upstream of Priest Rapids Dam (upstream of the Hanford Site) by the Hanford Site Surface Environmental Surveillance Project.

  12. Spectroscopic and diffraction study of uranium speciation in contaminated vadose zone sediments from the Hanford site, Washington state.

    PubMed

    Catalano, Jeffrey G; Heald, Steven M; Zachara, John M; Brown, Gordon E

    2004-05-15

    Contamination of vadose zone sediments under tank BX-102 at the Hanford site, Washington, resulted from the accidental release of 7-8 metric tons of uranium dissolved in caustic aqueous sludge in 1951. We have applied synchrotron-based X-ray spectroscopic and diffraction techniques to characterize the speciation of uranium in samples of these contaminated sediments. UIII-edge X-ray absorption fine structure (XAFS) spectroscopic studies demonstrate that uranium occurs predominantly as a uranium(VI) silicate from the uranophane group of minerals. XAFS cannot distinguish between the members of this mineral group due to the near identical local coordination environments of uranium in these phases. However, these phases differ crystallographically, and can be distinguished using X-ray diffraction (XRD) methods. As the concentration of uranium was too low for conventional XRD to detect these phases, X-ray microdiffraction (microXRD) was used to collect diffraction patterns on approximately 20 microm diameter areas of localized high uranium concentration found using microscanning X-ray fluorescence (microSXRF). Only sodium boltwoodite, Na(UO2)(SiO3OH) x 1.5H20, was observed; no other uranophane group minerals were present. Sodium boltwoodite formation has effectively sequestered uranium in these sediments under the current geochemical and hydrologic conditions. Attempts to remediate the uranium contamination will likely face significant difficulties because of the speciation and distribution of uranium in the sediments.

  13. Plutonium Contamination Issues in Hanford Soils and Sediments: Discharges from the Z-Plant (PFP) Complex

    SciTech Connect

    Felmy, Andrew R.; Cantrell, Kirk J.; Conradson, Steven D.

    2010-08-23

    Beginning in 1945, weapons production activities at the Hanford Nuclear Reservation resulted in the discharge of large quantities of Pu and other transuranic elements to the subsurface. The vast majority of the transuranics were disposed in the Hanford central plateau (200 areas) predominately associated with activities at the Z-Plant (Plutonium Finishing Plant) complex. In the past the Pu and Am migrated deep into the subsurface at certain locations, although the Pu and other transuranics are not currently being detected in significant concentration in any associated groundwaters. Evaluation of the chemical form of the transuranics in the subsurface along with determining the mechanism(s) of the past subsurface migration is important in establishing strategies for long-term site management practices. Unfortunately, the chemical form of the transuranics in the deep subsurface sediments and the past mechanism of vertical migration remain largely unknown. This paper present a summary of the different waste types and locations where transuranics were disposed, the factors that could have lead to subsurface migration via different transport vectors, the information currently available on the chemical form of Pu in the subsurface, and a summary of current research needs.

  14. Changes in uranium speciation through a depth sequence of contaminated Hanford sediments.

    PubMed

    Catalano, Jeffrey G; McKinley, James P; Zachara, John M; Heald, Steve M; Smith, Steven C; Brown, Gordon E

    2006-04-15

    The disposal of basic sodium aluminate and acidic U(VI)-Cu(ll) wastes in the now-dry North and South 300 A Process Ponds atthe Hanford site resulted in a groundwater plume of U(VI). To gain insight into the geochemical processes that occurred during waste disposal and those affecting the current and future fate and transport of this uranium plume, the solid-phase speciation of uranium in a depth sequence of sediments from the base of the North Process Pond through the vadose zone to groundwater was investigated using standard chemical and mineralogical analyses, electron and X-ray microprobe measurements, and X-ray absorption fine structure spectroscopy. Near-surface sediments contained uranium coprecipitated with calcite, which formed due to overneutralization of the waste ponds with base (NaOH). At intermediate depths in the vadose zone, metatorbernite [Cu(UO2PO4)2 x 8H2O] precipitated, likely during pond operations. Uranium occurred predominantly sorbed onto phyllosilicates in the deeper vadose zone and groundwater; sorbed uranium was also an important component at intermediate depths. Since the calcite-bearing pond sediments have been removed in remediation efforts, uranium fate and transport will be controlled primarily by desorption of the sorbed uranium and dissolution of metatorbernite.

  15. Geomicrobiology of High-Level Nuclear Waste-Contaminated Vadose Sediments at the Hanford Site, Washington State

    PubMed Central

    Fredrickson, James K.; Zachara, John M.; Balkwill, David L.; Kennedy, David; Li, Shu-mei W.; Kostandarithes, Heather M.; Daly, Michael J.; Romine, Margaret F.; Brockman, Fred J.

    2004-01-01

    Sediments from a high-level nuclear waste plume were collected as part of investigations to evaluate the potential fate and migration of contaminants in the subsurface. The plume originated from a leak that occurred in 1962 from a waste tank consisting of high concentrations of alkali, nitrate, aluminate, Cr(VI), 137Cs, and 99Tc. Investigations were initiated to determine the distribution of viable microorganisms in the vadose sediment samples, probe the phylogeny of cultivated and uncultivated members, and evaluate the ability of the cultivated organisms to survive acute doses of ionizing radiation. The populations of viable aerobic heterotrophic bacteria were generally low, from below detection to ∼104 CFU g−1, but viable microorganisms were recovered from 11 of 16 samples, including several of the most radioactive ones (e.g., >10 μCi of 137Cs/g). The isolates from the contaminated sediments and clone libraries from sediment DNA extracts were dominated by members related to known gram-positive bacteria. Gram-positive bacteria most closely related to Arthrobacter species were the most common isolates among all samples, but other phyla high in G+C content were also represented, including Rhodococcus and Nocardia. Two isolates from the second-most radioactive sample (>20 μCi of 137Cs g−1) were closely related to Deinococcus radiodurans and were able to survive acute doses of ionizing radiation approaching 20 kGy. Many of the gram-positive isolates were resistant to lower levels of gamma radiation. These results demonstrate that gram-positive bacteria, predominantly from phyla high in G+C content, are indigenous to Hanford vadose sediments and that some are effective at surviving the extreme physical and chemical stress associated with radioactive waste. PMID:15240306

  16. Characterization of uranium-contaminated sediments from beneath a nuclear waste storage tank from Hanford, Washington: Implications for contaminant transport and fate

    NASA Astrophysics Data System (ADS)

    Um, Wooyong; Icenhower, Jonathan P.; Brown, Christopher F.; Serne, R. Jeffery; Wang, Zheming; Dodge, Cleveland J.; Francis, Arokiasamy J.

    2010-02-01

    The concentration and distribution of uranium (U) in sediment samples from three boreholes recovered near radioactive waste storage tanks at Hanford, Washington, USA, were determined in detail using bulk and micro-analytical techniques. The source of contamination was a plume that contained an estimated 7000 kg of dissolved U that seeped into the subsurface as a result of an accident that occurred during filling of tank BX-102. The desorption character and kinetics of U were also determined by experiment in order to assess the mobility of U in the vadose zone. Most samples contained too little moisture to obtain quantitative information on pore water compositions. Concentrations of U (and contaminant phosphate—P) in pore waters were therefore estimated by performing 1:1 sediment-to-water extractions and the data indicated concentrations of these elements were above that of uncontaminated "background" sediments. Further extraction of U by 8 N nitric acid indicated that a significant fraction of the total U is relatively immobile and may be sequestered in mobilization-resistant phases. Fine- and coarse-grained samples in sharp contact with one another were sub-sampled for further scrutiny and identification of U reservoirs. Segregation of the samples into their constituent size fractions coupled with microwave-assisted digestion of bulk samples showed that most of the U contamination was sequestered within the fine-grained fraction. Isotope exchange ( 233U) tests revealed that ˜51% to 63% of the U is labile, indicating that the remaining fund of U is locked up in mobilization-resistant phases. Analysis by Micro-X-ray Fluorescence and Micro-X-ray Absorption Near-Edge Spectroscopy (μ-XRF and μ-XANES) showed that U is primarily associated with Ca and is predominately U(VI). The spectra obtained on U-enriched "hot spots" using Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLIFS) provide strong evidence for uranophane-type [Ca(UO 2) 2(SiO 3OH) 2(H 2O) 5

  17. Cation exchange reactions controlling desorption of Sr-90(2+) from coarse-grained contaminated sediments at the Hanford site, Washington

    SciTech Connect

    McKinley, James P.; Zachara, John M.; Smith, Steven C.; Liu, Chongxuan

    2007-01-15

    Nuclear waste that bore 90Sr2+ was accidentally leaked into the vadose zone at the Hanford site, and was immobilized at relatively shallow depths in sediments containing little apparent clay or silt-sized components. Sr2+, 90Sr2+, Mg2+, and Ca2+ was desorbed and total inorganic carbon concentration was monitored during the equilibration of this sediment with varying concentrations of Na+, Ca2+. A cation exchange model previously developed for similar sediments was applied to these results as a predictor of final solution compositions. The model included binary exchange reactions for the four operant cations and an equilibrium dissolution/precipitation reaction for calcite. The model successfully predicted the desorption data. The contaminated sediment was also examined using digital autoradiography, a sensitive tool for imaging the distribution of radioactivity. The exchanger phase containing 90Sr was found to consist of smectite formed from weathering of mesostasis glass in basaltic lithic fragments. These clasts are a significant component of Hanford formation sands. The relatively small but significant cation exchange capacity of these sediments was thus a consequence of reaction with physically sequestered clays in sediment that contained essentially no fine-grained material. The nature of this exchange component explained the relatively slow (scale of days) evolution of desorption solutions. The experimental and model results indicated that there is little risk of migration of 90Sr2+ to the water table.

  18. Characterization of uranium-contaminated sediments 3 from beneath a nuclear waste storage tank from Hanford, 4 Washington: Implications for contaminant transport and fate

    SciTech Connect

    Um, W.; Francis, A.; Icenhower, J. P.; Brown, C. F.; Serne, R. J.; Wang, Z.; Dodge, C. J.

    2010-01-01

    The concentration and distribution of uranium (U) in sediment samples from three boreholes recovered near radioactive waste storage tanks at Hanford, Washington, USA, were determined in detail using bulk and micro-analytical techniques. The source of contamination was a plume that contained an estimated 7000 kg of dissolved U that seeped into the subsurface as a result of an accident that occurred during filling of tank BX-102. The desorption character and kinetics of U were also determined by experiment in order to assess the mobility of U in the vadose zone. Most samples contained too little moisture to obtain quantitative information on pore water compositions. Concentrations of U (and contaminant phosphate-P) in pore waters were therefore estimated by performing 1:1 sediment-to-water extractions and the data indicated concentrations of these elements were above that of uncontaminated 'background' sediments. Further extraction of U by 8 N nitric acid indicated that a significant fraction of the total U is relatively immobile and may be sequestered in mobilization-resistant phases. Fine- and coarse-grained samples in sharp contact with one another were sub-sampled for further scrutiny and identification of U reservoirs. Segregation of the samples into their constituent size fractions coupled with microwave-assisted digestion of bulk samples showed that most of the U contamination was sequestered within the fine-grained fraction. Isotope exchange ({sup 233}U) tests revealed that {approx}51% to 63% of the U is labile, indicating that the remaining fund of U is locked up in mobilization-resistant phases. Analysis by Micro-X-ray Fluorescence and Micro-X-ray Absorption Near-Edge Spectroscopy ({mu}-XRF and {mu}-XANES) showed that U is primarily associated with Ca and is predominately U(VI). The spectra obtained on U-enriched 'hot spots' using Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLIFS) provide strong evidence for uranophane-type [Ca(UO{sub 2}){sub 2

  19. Characterization of Uranium-Contaminated Sediments From Beneath A Nuclear Waste Storage Tank From Hanford, Washington: Implications for Contaminant Transport and Fate

    SciTech Connect

    Um, Wooyong; Icenhower, Jonathan P; Brown, Christopher F; Serne, R Jeffrey; Wang, Zheming; Dodge, Cleveland J; FRANCIS, AROKIASAMY J

    2010-02-15

    The concentration and distribution of uranium (U) in sediment samples from three boreholes recovered near radioactive waste storage tanks at Hanford, Washington State, USA, were determined in detail using bulk and micro-analytical techniques. The source of contamination was a plume that contained an estimated 7000 kg of dissolved U that seeped into the subsurface as a result of an accident that occurred during filling of tank BX-102. The desorption character and kinetics of U were also determined by experiment in order to assess the mobility of U in the vadose zone. Most samples contained too little moisture to obtain quantitative information on pore water compositions. Concentrations of U (and contaminant phosphate—P) in pore waters were therefore estimated by performing 1:1 sediment-to-water extractions and the data indicated concentrations of these elements were above that of uncontaminated “background” sediments. Further extraction of U by 8 N nitric acid indicated that a significant fraction of the total U is relatively immobile and may be sequestered in mobilization-resistant phases. Fine- and coarse-grained samples in sharp contact with one another were sub-sampled for further scrutiny and identification of U reservoirs. Segregation of the samples into their constituent size fractions coupled with microwave-assisted digestion of bulk samples showed that most of the U contamination was sequestered within the fine-grained fraction. Isotope exchange (233U) tests revealed that ~51 to 63% of the U is labile, indicating that the remaining fund of U is locked up in mobilization-resistant phases. Analysis by micro-X-Ray Fluorescence and micro-X-Ray Absorption Near-Edge Spectroscopy (μ-XRF and μ-XANES) showed that U is primarily associated with Ca and is predominately U(VI). The spectra obtained on U-enriched “hot spots” using Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLIFS) provide strong evidence for uranophane-type [Ca(UO2

  20. Contaminated Sediment Core Profiling

    EPA Science Inventory

    Evaluating the environmental risk of sites containing contaminated sediments often poses major challenges due in part to the absence of detailed information available for a given location. Sediment core profiling is often utilized during preliminary environmental investigations ...

  1. Contaminated Aquatic Sediments.

    PubMed

    Jaglal, Kendrick

    2016-10-01

    A review of the literature published in 2015 relating to the assessment, evaluation and remediation of contaminated aquatic sediments is presented. The review is divided into the following main sections: policy and guidance, methodology, distribution, fate and transport, risk, toxicity and remediation. PMID:27620103

  2. Uranium Contamination at the 300 Area of the Hanford Site

    SciTech Connect

    Brown, Christopher F.; Serne, R. Jeffrey; Krupka, Kenneth M.; Pierce, Eric M.; Lindberg, Michael J.

    2005-01-24

    Release rates of uranium from contaminated sediments are dependent on several key environmental factors which significantly influence the fate and transport of uranium in sediments and groundwater. Two of these factors include the form(s) in which the uranium contamination exists in the sediments and the compositions of pore fluids and groundwater that will react with these sediments. Solid-phase characterization of one contaminated sample was used in conjunction with semi-selective extraction analyses of six samples collected from the 300 Area of the U.S. Department of Energy’s Hanford Site to identify the form of uranium in the sediments. Static and flow-through column leaching experiments were used to evaluate the effect of solution composition (i.e., ionic strength and carbonate concentration) on the leach rates of uranium from these sediments. Results of scanning electron microscopy analyses indicated that the majority of the uranium in the most contaminated sediment was present as discrete uranium phases (possibly as a calcium uranyl silicate) and co-precipitates. Column leach tests showed that uranium effluent concentrations did not achieve steady-state conditions over the duration of the experiments (several months); they continued to decrease slowly over time, indicating that the release of uranium from the contaminated sediments was a multi-rate kinetically controlled process. Subsequent static leach experiments on the residual column leached material indicated that uranium release from the contaminated sediments was highly dependent on U(VI) aqueous complexation with carbonate, with the percentage of remobilized uranium ranging from 0.05 to 27% over a range of carbonate solution concentrations from 0.87 to 12.2 mM, respectively.

  3. CONTAMINANTS IN WATER AND SEDIMENT

    EPA Science Inventory

    The Detroit River has experienced over a century of heavy contaminant discharges from industry and municipalities. The sources of contaminants vary, and include non-point sources, combined sewer overflows, point sources, tributaries, sediments, and upstream inputs. ---
    Demonst...

  4. Remediation technologies for contaminated sediments

    SciTech Connect

    Swanson, L.M.

    1995-09-01

    Although soil and groundwater remediation has been conducted for many years, sediment remediation is still in its infancy. Regulatory agencies are now beginning to identify areas where contaminated sediments exist and evaluate their environmental impact. As these evaluations are completed, the projects must shift focus to how these sediments can be remediated. Also as the criteria for aquatic disposal of dredged sediments become more stringent, remediation technologies must be developed to address contaminated sediments generated by maintenance dredging.This report describes the various issues and possible technologies for sediment remediation.

  5. HANDBOOK: REMEDIATION OF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Contaminated sediments may pose risks to both human and environmental health. Such sediments may be found in

    large sites, such as the harbors of industrialized ports. However, they are also frequently found in smaller sites, such as streams, lakes, bayous, and rivers. In r...

  6. Isotopic Studies of Contaminant Transport at the Hanford Site, Washington.

    SciTech Connect

    Christensen, John N.; Conrad, Mark E.; DePaolo, Donald J.; Dresel, P. Evan

    2007-11-01

    Processes of fluid flow and chemical transport through the vadose zone can be characterized through the isotopic systematics of natural soils, minerals, pore fluids and groundwater. In this contribution, we first review our research using measured isotopic variations, due both to natural and site related processes, of the elements H, O, N, Sr and U, to study the interconnection between vadose zone and groundwater contamination at the Hanford Site in south-central Washington. We follow this brief review with a presentation of new data pertaining to vadose zone and groundwater contamination in the WMA T-TX-TY vicinity. Uranium (U) isotopic data for the C3832 core (WMA TX) indicates the involvement of processed natural U fuel, and links the observed U contamination to the nearby single shelled tank TX-104. The data also precludes contamination from an early 1970’s TX-107 leak. In the case of the C4104 core (WMA T), the U isotopic data indicates a mixture of processed natural and enriched U fuels consistent with the major leak from T-106 in 1973. Uranium and Strontium isotopic data for the cores also provides direct evidence for chemical interaction between high-pH waste fluid and sediment. Isotopic data for groundwater nitrate contamination in the vicinity of WMA-T strongly suggests high-level tank waste (most likely from T-106) as the source of very high 99Tc concentrations recently observed at the NE corner of WMAT.

  7. Beneficial Use Of Contaminated Sediment

    EPA Science Inventory

    The western portion of the Lake George Branch of the Indian Harbor Canal (IHC) is no longer used for commercial purposes, but contains petroleum contaminated sediments. The IHC is considered an important habitat for many animal species. Several future development projects have ...

  8. Resource book: Decommissioning of contaminated facilities at Hanford

    SciTech Connect

    Not Available

    1991-09-01

    In 1942 Hanford was commissioned as a site for the production of weapons-grade plutonium. The years since have seen the construction and operation of several generations of plutonium-producing reactors, plants for the chemical processing of irradiated fuel elements, plutonium and uranium processing and fabrication plants, and other facilities. There has also been a diversification of the Hanford site with the building of new laboratories, a fission product encapsulation plant, improved high-level waste management facilities, the Fast Flux test facility, commercial power reactors and commercial solid waste disposal facilities. Obsolescence and changing requirements will result in the deactivation or retirement of buildings, waste storage tanks, waste burial grounds and liquid waste disposal sites which have become contaminated with varying levels of radionuclides. This manual was established as a written repository of information pertinent to decommissioning planning and operations at Hanford. The Resource Book contains, in several volumes, descriptive information of the Hanford Site and general discussions of several classes of contaminated facilities found at Hanford. Supplementing these discussions are appendices containing data sheets on individual contaminated facilities and sites at Hanford. Twelve appendices are provided, corresponding to the twelve classes into which the contaminated facilities at Hanford have been organized. Within each appendix are individual data sheets containing administrative, geographical, physical, radiological, functional and decommissioning information on each facility within the class. 68 refs., 54 figs., 18 tabs.

  9. Leaching tendencies of uranium and regulated trace metals from the Hanford Site 300 Area North Process Pond sediments

    SciTech Connect

    Serne, R.J.; LeGore, V.L.; Mattigod, S.V.

    1994-09-01

    Data are presented that address the leaching tendencies and the total chemical composition of metals in feed materials and soil-washed fines generated by Alternative Remediation Technology, Inc. during a pilot-scale soil physical separation test performed at the 300 Area North Process Pond (Facility 316-2) on the Hanford Site in the spring of 1994. Four 300 Area North Process Pond sediments and one sediment from outside the pond`s fenced area were leach-tested using the Toxicity Characteristic Leach Procedure (TCLP) and other modified US Environmental Protection Agency and American Society for Testing and Materials protocols. Finally, leachate from the most contaminated sediment was used to load the Hanford sediment obtained outside the facility to evaluate the potential for contaminant adsorption onto natural sediments. The sediment characterization, leach, and adsorption results will be used in the evaluation of remedial alternatives in the 300-FF-1 Operable Unit Remedial Investigation/Feasibility Study.

  10. Simultaneously Extracted Metals/Acid-Volatile Sulfide and Total Metals in Surface Sediment from the Hanford Reach of the Columbia RIver and the Lower Snake River

    SciTech Connect

    Patton, Gregory W.; Crecelius, Eric A.

    2001-01-24

    Metals have been identified as contaminants of concern for the Hanford Reach because of upriver mining, industrial activities, and past nuclear material production at the US Department of Energy's Hanford Site. This study was undertaken to better understand the occurrence and fate of metals in sediment disposition areas in the Columbia and Snake Rivers.

  11. Simultaneously Extracted Metals/Acid-Volatile Sulfide and Total Metals in Surface Sediment from the Hanford Reach of the Columbia River and the Lower Snake River

    SciTech Connect

    Patton, Gregory W; Crecelius, Eric A

    2001-01-24

    Metals have been identified as contaminants of concern for the Hanford Reach because of upriver mining, industrial activities, and past nuclear material production at the US Department of Energy's Hanford Site. This study was undertaken to better understand the occurrence and fate of metals in sediment disposition areas in the Columbia and Snake Rivers.

  12. Isotopic Tracers for Biogeochemical Processes and Contaminant Transport: Hanford, Washington

    SciTech Connect

    Donald J. DePaolo; John N. Christensen; Mark E. Conrad; and P. Evan Dresel

    2007-04-19

    Our goal is to use isotopic measurements to understand how contaminants are introduced to and stored in the vadose zone, and what processes control migration from the vadose zone to groundwater and then to surface water. We have been using the Hanford Site in south-central Washington as our field laboratory, and our investigations are often stimulated by observations made as part of the groundwater monitoring program and vadose zone characterization activities. Understanding the transport of contaminants at Hanford is difficult due to the presence of multiple potential sources within small areas, the long history of activities, the range of disposal methods, and the continuing evolution of the hydrological system. Observations often do not conform to simple models, and cannot be adequately understood with standard characterization approaches, even though the characterization activities are quite extensive. One of our objectives is to test the value of adding isotopic techniques to the characterization program, which has the immediate potential benefit of addressing specific remediation issues, but more importantly, it allows us to study fundamental processes at the scale and in the medium where they need to be understood. Here we focus on two recent studies at the waste management area (WMA) T-TX-TY, which relate to the sources and transport histories of vadose zone and groundwater contamination and contaminant fluid-sediment interaction. The WMA-T and WMA-TX-TY tank farms are located within the 200 West Area in the central portion of the Hanford Site (Fig. 2). They present a complicated picture of mixed groundwater plumes of nitrate, {sup 99}Tc, Cr{sup 6+}, carbon tetrachloride, etc. and multiple potential vadose zone sources such as tank leaks and disposal cribs (Fig. 3). To access potential vadose zone sources, we analyzed samples from cores C3832 near tank TX-104 and from C4104 near tank T-106. Tank T-106 was involved in a major event in 1973 in which 435,000 L

  13. Influence of sediment storage on downstream delivery of contaminated sediment

    USGS Publications Warehouse

    Malmon, D.V.; Reneau, S.L.; Dunne, T.; Katzman, D.; Drakos, P.G.

    2005-01-01

    Sediment storage in alluvial valleys can strongly modulate the downstream migration of sediment and associated contaminants through landscapes. Traditional methods for routing contaminated sediment through valleys focus on in-channel sediment transport but ignore the influence of sediment exchanges with temporary sediment storage reservoirs outside the channel, such as floodplains. In theory, probabilistic analysis of particle trajectories through valleys offers a useful strategy for quantifying the influence of sediment storage on the downstream movement of contaminated sediment. This paper describes a field application and test of this theory, using 137Cs as a sediment tracer over 45 years (1952-1997), downstream of a historical effluent outfall at the Los Alamos National Laboratory (LANL), New Mexico. The theory is parameterized using a sediment budget based on field data and an estimate of the 137Cs release history at the upstream boundary. The uncalibrated model reasonably replicates the approximate magnitude and spatial distribution of channel- and floodplain-stored 137Cs measured in an independent field study. Model runs quantify the role of sediment storage in the long-term migration of a pulse of contaminated sediment, quantify the downstream impact of upstream mitigation, and mathematically decompose the future 137Cs flux near the LANL property boundary to evaluate the relative contributions of various upstream contaminant sources. The fate of many sediment-bound contaminants is determined by the relative timescales of contaminant degradation and particle residence time in different types of sedimentary environments. The theory provides a viable approach for quantifying the long-term movement of contaminated sediment through valleys. Copyright 2005 by the American Geophysical Union.

  14. Sediment quality criteria: A review with recommendations for developing criteria for the Hanford Site

    SciTech Connect

    Driver, C.J.

    1994-05-01

    Criteria for determining the quality of liver sediment are necessary to ensure that concentrations of contaminants in aquatic systems are within acceptable limits for the protection of aquatic and human life. Such criteria should facilitate decision-making about remediation, handling, and disposal of contaminants. Several approaches to the development of sediment quality criteria (SQC) have been described and include both descriptive and numerical methods. However, no single method measures all impacts at all times to all organisms (U.S. EPA 1992b). The U.S. EPA`s interest is primarily in establishing chemically based, numerical SQC that are applicable nation-wide (Shea 1988). Of the approaches proposed for SQC development, only three are being considered for numerical SQC on a national level. These approaches include an Equilibrium Partitioning Approach, a site-specific method using bioassays (the Apparent Effects Threshold Approach), and an approach similar to EPA`s water quality criteria (Pavlou and Weston 1984). Although national (or even regional) criteria address a number of political, litigative, and engineering needs, some researchers feel that protection of benthic communities require site-specific, biologically based criteria (Baudo et al. 1990). This is particularly true for areas where complex mixtures of contaminants are present in sediments. Other scientifically valid and accepted procedures for freshwater SQC include a background concentration approach, methods using field or spiked bioassays, a screening level concentration approach, the Apparent Effects Threshold Approach, the Sediment Quality Triad, the International Joint Commission Sediment Assessment Strategy, and the National Status and Trends Program Approach. The various sediment assessment approaches are evaluated for application to the Hanford Reach and recommendations for Hanford Site sediment quality criteria are discussed.

  15. The Influence of Calcium Carbonate Grain Coatings on Contaminant Reactivity in Vadose Zone Sediments

    SciTech Connect

    Zachara, John M.; Chambers, Scott; Brown Jr., Gordon E.; Eggleston, Carrick M.

    2001-06-01

    Calcium carbonate (CaCO3) is widely distributed through the Hanford vadose zone as a minor phase. As a result of current and past geochemical processes, CaCO3 exists as grain coatings, intergrain fill, and distinct caliche layers in select locations. Calcium carbonate may also precipitate when high-level wastes react with naturally Ca- and Mg-saturated Hanford sediments. Calcium carbonate is a very reactive mineral phase. Sorption reactions on its surface may slow the migration of certain contaminants (Co, Sr), but its surface coatings on other mineral phases may diminish contaminant retardation (for example, Cr) by blocking surface reaction sites of the substrate. This project explores the behavior of calcium carbonate grain coatings, including how they form and dissolve, their reactivity toward key Hanford contaminants, their impact (as surface coatings) on the reactivity of other mineral substrates, and on their in-ground composition and minor element enrichment. The importance of CaCO3 as a contaminant sorbent will be defined in all of its different manifestations in Hanford sediments: dispersed minor lithic fragments, pedogenic carbonate coatings on gravel and stringers in silt, and nodules in clay and paleosols. Mass action models will be developed that allow understanding and prediction of the geochemical effects of CaCO3 on contaminant retardation in Hanford sediments.

  16. Distribution and Retention of 137Cs in Sediments at the Hanford Site, Washington

    SciTech Connect

    McKinley, James P.; Zeissler, C. J.; Zachara, John M.; Serne, R. Jeffrey; Lindstrom, Richard M.; Schaef, Herbert T.; Orr, Robert D.

    2001-07-25

    {sup 137}Cesium and other contaminants have leaked from high level waste (HLW) single-shell storage tanks (SSTs) at the Hanford Site in southeastern Washington. {sup 137}Cesium and other contaminants have leaked from single-shell storage tanks (SSTs) into coarse-textured, relatively unweathered unconsolidated sediments. Contaminated sediments were retrieved from beneath a leaky SST to investigate the distribution of adsorbed {sup 137}Cs{sup +} across different sediment size fractions. All fractions contained mica (biotite, muscovite, vermiculatized biotite), quartz, and plagioclase along with smectite and kaolinite in the clay-size fraction. A phosphor-plate autoradiograph method was used to identify particular sediment particles responsible for retaining {sup 137}Cs{sup +}. The Cs-bearing particles were found to be individual mica flakes or agglomerated smectite, mica, quartz, and plagioclase. Of these, only the micaceous component was capable of sorbing Cs{sup +} strongly. Sorbed {sup 137}Cs{sup +} could not be significantly removed from sediments by leaching with dithionite citrate buffer or KOH, but a fraction of the sorbed {sup 137}Cs{sup +} (5?22%) was desorbable with solutions containing an excess of Rb{sup +}. The small amount of {sup 137}Cs{sup +} that might be mobilized by migrating fluids in the future would likely sorb to nearby micaceous clasts in downgradient sediments.

  17. Final Project Report: Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    SciTech Connect

    Jon Chorover, University of Arizona; Peggy O'€™Day, University of California, Merced; Karl Mueller, Penn State University; Wooyong Um, Pacific Northwest National Laboratory; Carl Steefel, Lawrence Berkeley National Laboratory

    2012-10-01

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided detailed characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions.

  18. Evaluating Contaminant Flux from the Vadose Zone to the Groundwater in the Hanford Central Plateau. SX Tank Farms Case Study

    SciTech Connect

    Truex, Michael J.; Oostrom, Martinus; Last, George V.; Strickland, Christopher E.; Tartakovsky, Guzel D.

    2015-09-01

    At the DOE Hanford Site, contaminants were discharged to the subsurface through engineered waste sites in the Hanford Central Plateau. Additional waste was released through waste storage tank leaks. Much of the contaminant inventory is still present within the unsaturated vadose zone sediments. The nature and extent of future groundwater contaminant plumes and the growth or decline of current groundwater plumes beneath the Hanford Central Plateau are a function of the contaminant flux from the vadose zone to the groundwater. In general, contaminant transport is slow through the vadose zone and it is difficult to directly measure contaminant flux in the vadose zone. Predictive analysis, supported by site characterization and monitoring data, was applied using a structured, systems-based approach to estimate the future contaminant flux to groundwater in support of remediation decisions for the vadose zone and groundwater (Truex and Carroll 2013). The SX Tank Farm was used as a case study because of the existing contaminant inventory in the vadose zone, observations of elevated moisture content in portions of the vadose zone, presence of a limited-extent groundwater plume, and the relatively large amount and wide variety of data available for the site. Although the SX Tank Farm case study is most representative of conditions at tank farm sites, the study has elements that are also relevant to other types of disposal sites in the Hanford Central Plateau.

  19. Distribution of microbial biomass and potential for anaerobic respiration in Hanford Site 300 Area subsurface sediment.

    PubMed

    Lin, Xueju; Kennedy, David; Peacock, Aaron; McKinley, James; Resch, Charles T; Fredrickson, James; Konopka, Allan

    2012-02-01

    Subsurface sediments were recovered from a 52-m-deep borehole cored in the 300 Area of the Hanford Site in southeastern Washington State to assess the potential for biogeochemical transformation of radionuclide contaminants. Microbial analyses were made on 17 sediment samples traversing multiple geological units: the oxic coarse-grained Hanford formation (9 to 17.4 m), the oxic fine-grained upper Ringold formation (17.7 to 18.1 m), and the reduced Ringold formation (18.3 to 52 m). Microbial biomass (measured as phospholipid fatty acids) ranged from 7 to 974 pmols per g in discrete samples, with the highest numbers found in the Hanford formation. On average, strata below 17.4 m had 13-fold less biomass than those from shallower strata. The nosZ gene that encodes nitrous oxide reductase (measured by quantitative real-time PCR) had an abundance of 5 to 17 relative to that of total 16S rRNA genes below 18.3 m and <5 above 18.1 m. Most nosZ sequences were affiliated with Ochrobactrum anthropi (97 sequence similarity) or had a nearest neighbor of Achromobacter xylosoxidans (90 similarity). Passive multilevel sampling of groundwater geochemistry demonstrated a redox gradient in the 1.5-m region between the Hanford-Ringold formation contact and the Ringold oxic-anoxic interface. Within this zone, copies of the dsrA gene and Geobacteraceae had the highest relative abundance. The majority of dsrA genes detected near the interface were related to Desulfotomaculum spp. These analyses indicate that the region just below the contact between the Hanford and Ringold formations is a zone of active biogeochemical redox cycling. PMID:22138990

  20. Remediation technologies for oil-contaminated sediments.

    PubMed

    Agarwal, Ashutosh; Liu, Yu

    2015-12-30

    Oil-contaminated sediments pose serious environmental hazards for both aquatic and terrestrial ecosystems. Innovative and environmentally compatible technologies are urgently required to remove oil-contaminated sediments. In this paper, various physical, chemical and biological technologies are investigated for the remediation of oil-contaminated sediments such as flotation and washing, coal agglomeration, thermal desorption, ultrasonic desorption, bioremediation, chemical oxidation and extraction using ionic liquids. The basic principles of these technologies as well as their advantages and disadvantages for practical application have been discussed. A combination of two or more technologies is expected to provide an innovative solution that is economical, eco-friendly and adaptable. PMID:26414316

  1. Remediation technologies for oil-contaminated sediments.

    PubMed

    Agarwal, Ashutosh; Liu, Yu

    2015-12-30

    Oil-contaminated sediments pose serious environmental hazards for both aquatic and terrestrial ecosystems. Innovative and environmentally compatible technologies are urgently required to remove oil-contaminated sediments. In this paper, various physical, chemical and biological technologies are investigated for the remediation of oil-contaminated sediments such as flotation and washing, coal agglomeration, thermal desorption, ultrasonic desorption, bioremediation, chemical oxidation and extraction using ionic liquids. The basic principles of these technologies as well as their advantages and disadvantages for practical application have been discussed. A combination of two or more technologies is expected to provide an innovative solution that is economical, eco-friendly and adaptable.

  2. Status of outdoor radioactive contamination at the Hanford Site

    SciTech Connect

    McKinney, S.M.; Markes, B.M.

    1994-12-01

    This document summarizes the status of outdoor radioactive contamination near Hanford Site facilities and disposal sites. It defines the nature and areal extend of the radioactively contaminated areas and describes the historical, ongoing, and planned radiological monitoring and control activities. Radioactive waste has been disposed of to the soil column since shortly after the reactors and production facilities began operating. Radioactive liquid wastes were placed directly into the ground via liquid discharges to cribs, ponds, ditches, and reverse wells. Solid wastes were placed in trenches, burial vaults, and caissons. Although the Hanford Site covers 1,450 km{sup 2}, the radioactively contaminated area is only about 36 km{sup 2} or 2.5% of the original site. Over time, contamination has migrated from some of the waste management sites through various vectors (e.g., burrowing animals, deep-rooted vegetation, erosion, containment system failure) or has been deposited to the surface soil via spills and unplanned releases (e.g., line leaks/breaks, tank leaks, and stack discharges) and created areas of outdoor radioactivity both on and below the surface. Currently 26 km{sup 2} are posted as surface contamination and 10 km{sup 2} are posted as underground contamination.

  3. Characterization and remediation of highly radioactive contaminated soil at Hanford

    SciTech Connect

    Buckmaster, M.A.; Erickson, J.K.

    1993-09-01

    The Hanford Site, Richland, Washington, contains over 1,500 identified waste sites and numerous groundwater plumes that will be characterized and remediated over the next 30 years. As a result of the Hanford Federal Facility Agreement and Consent Order, the US Department of Energy (DOE) has initiated a remedial investigation/feasibility study (RI/FS) at the 200-BP-1 operable unit. The 200-BP-1 RI/FS is the first Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) investigation on the Hanford Site that involves highly radioactive and chemically contaminated soils. The initial phase of site characterization was designed to assess the nature and extent of contamination associated with the source waste sites within the 200-BP-1 operable unit. Characterization activities consisted of drilling and sampling, chemical and physical analysis of samples, and development of a conceptual vadose zone model. These data were then used. to develop remedial alternatives during the FS evaluation. The preferred alternative resulting from the RI/FS process for the 200-BP-1 operable unit is to construct a surface isolation barrier. The multi-layered earthen barrier will be designed to prevent migration of contaminants resulting from water infiltration, biointrusion, and wind and water erosion.

  4. Survey of radiological contaminants in the near-shore environment at the Hanford Site 100-N Area reactor

    SciTech Connect

    Van Verst, S.P.; Albin, C.L.; Patton, G.W.; Blanton, M.L.; Poston, T.M.; Cooper, A.T.; Antonio, E.J.

    1998-09-01

    Past operations at the Hanford Site 100-N Area reactor resulted in the release of radiological contaminants to the soil column, local groundwater, and ultimately to the near-shore environment of the Columbia River. In September 1997, the Washington State Department of Health (WDOH) and the Hanford Site Surface Environmental Surveillance Project (SESP) initiated a special study of the near-shore vicinity at the Hanford Site`s retired 100-N Area reactor. Environmental samples were collected and analyzed for radiological contaminants ({sup 3}H, {sup 90}Sr, and gamma/ emitters), with both the WDOH and SESP analyzing a portion of the samples. Samples of river water, sediment, riverbank springs, periphyton, milfoil, flying insects, clam shells, and reed canary grass were collected. External exposure rates were also measured for the near-shore environment in the vicinity of the 100-N Area. In addition, samples were collected at background locations above Vernita Bridge.

  5. U(VI) adsorption on aquifer sediments at the Hanford Site.

    PubMed

    Um, Wooyong; Serne, R Jeffrey; Brown, Christopher F; Last, George V

    2007-08-15

    Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch K(d) values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10(-6) M (238 microg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption K(d) values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption K(d) values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected.

  6. MEASURING CONTAMINANT RESUSPENSION RESULTING FROM SEDIMENT CAPPING

    EPA Science Inventory

    This Sediment Issue summarizes two studies undertaken at marine sites by the National Risk Management Research Laboratory of U.S. EPA to evaluate the resuspension of surface materials contaminated with polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) b...

  7. Solid-waste leach characteristics and contaminant-sediment interactions. Volume 1, Batch leach and adsorption tests and sediment characterization

    SciTech Connect

    Serne, R.J.; LeGore, V.L.; Cantrell, K.J.; Lindenmeier, C.W.; Campbell, J.A.; Amonette, J.E.; Conca, J.L.; Wood, M.I.

    1993-10-01

    The objectives of this report and subsequent volumes include describing progress on (1) development of conceptual-release models for Hanford Site defense solid-waste forms; (2) optimization of experimental methods to quantify the release from contaminants from solid wastes and their subsequent interactions with unsaturated sediments; and (3) creation of empirical data for use as provisional source term and retardation factors that become input parameters for performance assessment analyses for future Hanford disposal units and baseline risk assessments for inactive and existing disposal units.

  8. Redistribution of intertidal sediment contaminants by microphytobenthos

    NASA Astrophysics Data System (ADS)

    Becker, Amani; Copplestone, David; Tyler, Andrew; Smith, Nick; Sneddon, Christopher

    2014-05-01

    Microphytobenthos (MPB) is a mixed community of microscopic algae inhabiting the top few millimetres of bottom sediment in the intertidal zone. It is a key component of the estuarine ecosystem, interacting with the sediment and fauna to influence sediment distribution and resuspension and forming the base of the estuarine food chain. Estuarine sediments, with which the MPB is closely associated, are a significant sink for contaminants from both fluvial and marine sources. Algae are known to have the capacity to take up contaminants, and the phytoplankton has been well studied in this respect, however there has been little research involving MPB. The extent to which contaminant uptake by MPB occurs and under what conditions is therefore very poorly understood. It seems probable that the paucity of research in this area is due to the complexity of the bioavailability of contaminants in the intertidal zone coupled with difficulties in separating MPB from the sediment. A series of experiments are proposed in which we will investigate (at a range of spatial scales) contaminant partitioning in the presence of MPB; the effect of changing temperatures on contaminant uptake and toxicity to MPB; effects of sediment resuspension on contaminant availability and uptake to MPB; and the uptake of contaminants from MPB to molluscs. A mesocosm (or experimental enclosure) is being constructed to replicate the natural system and enable manipulation of conditions of interest. This will attain greater realism than laboratory toxicity tests, with more statistical power than can be achieved through field studies. By gaining a better understanding of processes governing contaminant bioavailability and mechanisms for uptake by MPB it will be possible to relate these to projected climate change effects and ascertain potential consequences for contaminant redistribution.

  9. Microscale geochemical gradients in Hanford 300 Area sediment biofilms and influence of uranium

    SciTech Connect

    Nguyen, Hung D.; Cao, Bin; Mishra, Bhoopesh; Boyanov, Maxim I.; Kemner, Kenneth M.; Fredrickson, Jim K.; Beyenal, Haluk

    2012-01-01

    The presence and importance of microenvironments in the subsurface at contaminated sites were suggested by previous geochemical studies. However, no direct quantitative characterization of the geochemical microenvironments had been reported. We quantitatively characterized microscale geochemical gradients (dissolved oxygen (DO), H(2), pH, and redox potential) in Hanford 300A subsurface sediment biofilms. Our results revealed significant differences in geochemical parameters across the sediment biofilm/water interface in the presence and absence of U(VI) under oxic and anoxic conditions. While the pH was relatively constant within the sediment biofilm, the redox potential and the DO and H(2) concentrations were heterogeneous at the microscale (<500-1000 μm). We found microenvironments with high DO levels (DO hotspots) when the sediment biofilm was exposed to U(VI). On the other hand, we found hotspots (high concentrations) of H(2) under anoxic conditions both in the presence and in the absence of U(VI). The presence of anoxic microenvironments inside the sediment biofilms suggests that U(VI) reduction proceeds under bulk oxic conditions. To test this, we operated our biofilm reactor under air-saturated conditions in the presence of U(VI) and characterized U speciation in the sediment biofilm. U L(III)-edge X-ray absorption spectroscopy (XANES and EXAFS) showed that 80-85% of the U was in the U(IV) valence state.

  10. Ecological benefits of contaminated sediment remediation.

    PubMed

    Zarull, Michael A; Hartig, John H; Krantzberg, Gail

    2002-01-01

    Contaminated sediment has been identified as a source of ecological impacts in marine and freshwater systems throughout the world, and the importance of the contaminated sediment management issue continues to increase in all industrialized countries. In many areas, dredging or removal of sediments contaminated with nutrients, metals, oxygen-demanding substances, and persistent toxic organic chemicals has been employed as a form of environmental remediation. In most situations, however, the documentation of the sediment problem has not been quantitatively coupled to ecological impairments. In addition, the lack of long-term, postactivity research and monitoring for most projects has impeded a better understanding of the ecological significance of sediment contamination. Establishing quantitatively the ecological significance of sediment-associated contamination in any area is a difficult time- and resource-consuming exercise. It is, however, absolutely essential that it be done. Such documentation will likely be used as the justification for remedial and rehabilitative action(s) and also as the rationale for proposing when intervention is necessary in one place but not another. Bounding the degree of ecological impact (at least semiquantitatively) provides for realistic expectations for improvement if sediment remediation is to be pursued. It should also provide essential information on linkages that could be used in rehabilitating other ecosystem components such as fish or wildlife habitat. The lack of information coupling contaminated sediment to specific ecological impairments has, in many instances, precluded a clear estimate of how much sediment requires action to be taken, why, and what improvements can be expected to existing impairment(s) over time. Also, it has likely resulted in either a delay in remedial action or abandonment of the option altogether. A clear understanding of ecological links not only provides adequate justification for a cleanup program

  11. Prototype Data Models and Data Dictionaries for Hanford Sediment Physical and Hydraulic Properties

    SciTech Connect

    Rockhold, Mark L.; Last, George V.; Middleton, Lisa A.

    2010-09-30

    The Remediation Decision Support (RDS) project, managed by the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE) and the CH2M HILL Plateau Remediation Company (CHPRC), has been compiling physical and hydraulic property data and parameters to support risk analyses and waste management decisions at Hanford. In FY09 the RDS project developed a strategic plan for a physical and hydraulic property database. This report documents prototype data models and dictionaries for these properties and associated parameters. Physical properties and hydraulic parameters and their distributions are required for any type of quantitative assessment of risk and uncertainty associated with predictions of contaminant transport and fate in the subsurface. The central plateau of the Hanford Site in southeastern Washington State contains most of the contamination at the Site and has up to {approx}100 m of unsaturated and unconsolidated or semi-consolidated sediments overlying the unconfined aquifer. These sediments contain a wide variety of contaminants ranging from organic compounds, such as carbon tetrachloride, to numerous radionuclides including technetium, plutonium, and uranium. Knowledge of the physical and hydraulic properties of the sediments and their distributions is critical for quantitative assessment of the transport of these contaminants in the subsurface, for evaluation of long-term risks and uncertainty associated with model predictions of contaminant transport and fate, and for evaluating, designing, and operating remediation alternatives. One of the goals of PNNL's RDS project is to work with the Hanford Environmental Data Manager (currently with CHPRC) to develop a protocol and schedule for incorporation of physical property and hydraulic parameter datasets currently maintained by PNNL into HEIS. This requires that the data first be reviewed to ensure quality and consistency. New data models must then be developed for HEIS that are

  12. Geochemical Characterization of Chromate Contamination in the 100 Area Vadose Zone at the Hanford Site

    SciTech Connect

    Dresel, P. Evan; Qafoku, Nikolla; McKinley, James P.; Fruchter, Jonathan S.; Ainsworth, Calvin C.; Liu, Chongxuan; Ilton, Eugene S.; Phillips, J. L.

    2008-07-16

    The major objectives of the proposed study were to: 1.) determine the leaching characteristics of hexavalent chromium [Cr(VI)] from contaminated sediments collected from 100 Area spill sites; 2.) elucidate possible Cr(VI) mineral and/or chemical associations that may be responsible for Cr(VI) retention in the Hanford Site 100 Areas through the use of i.) macroscopic leaching studies and ii.) microscale characterization of contaminated sediments; and 3.) provide information to construct a conceptual model of Cr(VI) geochemistry in the Hanford 100 Area vadose zone. In addressing these objectives, additional benefits accrued were: (1) a fuller understanding of Cr(VI) entrained in the vadose zone that will that can be utilized in modeling potential Cr(VI) source terms, and (2) accelerating the Columbia River 100 Area corridor cleanup by providing valuable information to develop remedial action based on a fundamental understanding of Cr(VI) vadose zone geochemistry. A series of macroscopic column experiments were conducted with contaminated and uncontaminated sediments to study Cr(VI) desorption patterns in aged and freshly contaminated sediments, evaluate the transport characteristics of dichromate liquid retrieved from old pipelines of the 100 Area; and estimate the effect of strongly reducing liquid on the reduction and transport of Cr(VI). Column experiments used the < 2 mm fraction of the sediment samples and simulated Hanford groundwater solution. Periodic stop-flow events were applied to evaluate the change in elemental concentration during time periods of no flow and greater fluid residence time. The results were fit using a two-site, one dimensional reactive transport model. Sediments were characterized for the spatial and mineralogical associations of the contamination using an array of microscale techniques such as XRD, SEM, EDS, XPS, XMP, and XANES. The following are important conclusions and implications. Results from column experiments indicated that most

  13. An Experimental Study of Diffusivity of Technetium-99 in Hanford Vadose Zone Sediments

    SciTech Connect

    Mattigod, Shas V.; Bovaird, Chase C.; Wellman, Dawn M.; Parker, Kent E.; Wood, Marcus I.

    2012-11-01

    One of the methods being considered at the Hanford site in Washington for safely disposing of low-level radioactive wastes (LLW) is to encase the waste in concrete and entomb the packages in the Hanford vadose zone sediments. The current plan for waste isolation consists of stacking low-level waste packages on a trench floor, surrounding the stacks with reinforced steel, and encasing these packages with concrete. Any failure of the concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The mobilized radionuclides may escape from the encased concrete by mass flow and/or diffusion and move into the surrounding subsurface sediments. It is therefore necessary to conduct an assessment of the performance of the concrete encasement structure and the surrounding soil’s ability to retard radionuclide migration. The retardation factors for radionuclides contained in the waste packages can be determined from measurements of diffusion coefficients for these contaminants through concrete and fill material. Because of their anionic nature in aqueous solutions, the radionuclides, 99Tc and 129I were identified as long-term dose contributors in LLW. The leachability and/or diffusion of these radionuclide species must be measured in order to assess the long-term performance of waste grouts when contacted with vadose-zone porewater or groundwater. To measure the diffusivity, a set of experiments were conducted using 99Tc-spiked concrete (with 0 and 4% metallic iron additions) in contact with unsaturated soil half-cells that reflected the typical moisture contents of Hanford vadose zone sediments. The 99Tc diffusion profiles in the soil half cells were measured after a time lapse of ~1.9 yr. Using the concentration profiles, the 99Tc diffusivity coefficients were calculated based on Fick’s Second Law.

  14. Contaminated sediment dynamics in peatland headwaters

    NASA Astrophysics Data System (ADS)

    Shuttleworth, Emma; Clay, Gareth; Evans, Martin; Hutchinson, Simon; Rothwell, James

    2016-04-01

    Peatlands are an important store of soil carbon, provide multiple ecosystem services, and when located in close proximity to urban and industrial areas, can also act as sinks of atmospherically deposited heavy metals. The near-surface layer of the blanket peats of the Peak District National Park, UK, is severely contaminated with high concentrations of anthropogenically derived, atmospherically deposited lead (Pb). These peats are severely degraded, and there is increasing concern that erosion is releasing considerable quantities of this legacy pollution into surface waters. Despite substantial research into Pb dynamics in peatlands formal description of the possible mechanisms of contaminated sediment mobilisation is limited. However, there is evidence to suggest that a substantial proportion of contaminated surface sediment may be redistributed elsewhere in the catchment. This study uses the Pb contamination stored near the peat's surface as a fingerprint to trace contaminated sediment dynamics and storage in three severely degraded headwater catchments. Erosion is exposing high concentrations of Pb on interfluve surfaces, and substantial amounts of reworked contaminated material are stored on other catchment surfaces (gully walls and floors). We propose a variety of mechanisms as controls of Pb release and storage on the different surfaces, including: (i) wind action on interfluves; (ii) the aspect of gully walls, and (iii) gully depth. Vegetation also plays an important role in retaining contaminated sediment on all surfaces.

  15. Impact Of Groundwater Discharge On Contaminant Behavior In Sediments

    EPA Science Inventory

    The discharge of groundwater into surface water may influence the concentrations and availability of contaminants in sediments. There are three predominant pathways by which groundwater may affect the characteristics of contaminated sediments: 1) direct contribution of contamin...

  16. Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    SciTech Connect

    Chorover, Jon; Perdrial, Nico; Mueller, Karl; Strepka, Caleb; O’Day, Peggy; Rivera, Nelson; Um, Wooyong; Chang, Hyun-Shik; Steefel, Carl; Thompson, Aaron

    2012-11-05

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, partial pressure of carbon dioxide, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. In this final report, we provide detailed descriptions of our results from this three-year study, completed in 2012 following a one-year no cost extension.

  17. STRATEGIES FOR IMMOBILIZATION OF DEEP VADOSE ZONE CONTAMINANTS AT THE HANFORD CENTRAL PLATEAU

    SciTech Connect

    CHRONISTER GB

    2011-01-14

    Deep vadose zone contamination poses some of the most difficult remediation challenges for the protection of groundwater at the Hanford Site in Richland, Washington. This paper describes processes and technologies being developed to use in the ongoing effort to remediate the contamination in the deep vadose zone at the Hanford Site.

  18. Toxicology profiles of chemical and radiological contaminants at Hanford

    SciTech Connect

    Harper, B.L.; Strenge, D.L.; Stenner, R.D.; Maughan, A.D.; Jarvis, M.K.

    1995-07-01

    This document summarizes toxicology information required under Section 3.3 (Toxicity Assessment) of HSRAM, and can also be used to develop the short toxicology profiles required in site assessments (described in HSRAM, Section 3.3.5). Toxicology information is used in the dose-response step of the risk assessment process. The dose-response assessment describes the quantitative relationship between the amount of exposure to a substance and the extent of toxic injury or disease. Data are derived from animal studies or, less frequently, from studies in exposed human populations. The risks of a substance cannot be ascertained with any degree of confidence unless dose-response relations are quantified. This document summarizes dose-response information available from the US Environmental Protection Agency (EPA). The contaminants selected for inclusion in this document represent most of the contaminants found at Hanford (both radiological and chemical), based on sampling and analysis performed during site investigations, and historical information on waste disposal practices at the Hanford Site.

  19. Effect of Saline Waste Solution Infiltration Rates on UraniumRetention and Spatial Distribution in Hanford Sediments

    SciTech Connect

    Wan, Jiamin; Tokunaga, Tetsu K.; Kim, Yongman; Wang, Zheming; Lanzirotti, Antonio; Saiz, Eduardo; Serne, R. Jeffrey

    2007-03-15

    The accidental overfilling of waste liquid from tank BX-102 at the Hanford Site in 1951 put about 10 metric tons of U(VI) into the vadose zone. In order to understand the dominant geochemical reactions and transport processes occurred during the initial infiltration and help understand current spatial distribution, we simulated the waste liquid spilling event in laboratory sediment columns using synthesized metal waste solution. We found that, as the plume propagating through sediments, pH decreased greatly (as much as 4 units) at the moving plume front. Infiltration flow rates strongly affect U behavior. Slower flow rates resulted in higher sediment-associated U concentrations, and higher flow rates ({ge} 5 cm/day) permitted practically unretarded U transport. Therefore, given the very high K{sub sat} of most of Hanford formation, the low permeability zones within the sediment could have been most important in retaining high concentrations of U during initial release into the vadose zone. Massive amount of colloids, including U-colloids, formed at the plume fronts. Total U concentrations (aqueous and colloid) within plume fronts exceeded the source concentration by up to 5-fold. Uranium colloid formation and accumulation at the neutralized plume front could be one mechanism responsible for highly heterogeneous U distribution observed in the contaminated Hanford vadose zone.

  20. A Physiochemical Analysis of the Mechanisms for Transport and Retention of Technetium (Tc-99) in Hanford Sediments

    NASA Astrophysics Data System (ADS)

    Jansik, D. P.; Wellman, D. M.; Istok, J. D.; Cordova, E.

    2011-12-01

    The transport of technetium (Tc-99), like many other radionuclides, is of interest due to the potential for human exposure and impact on ecosystems. Technetium has been released to the environment through nuclear power production and nuclear fuel processing; as a result, further spreading of Tc-99 is a concern at DOE sites across the US. Specifically, technetium is a contaminant of concern at Hanford and Savannah River. The current body of work conducted on Tc-99 has provided a wealth of information regarding the redox relationships, sorption, solubility, and stability of the mineral phases (Artinger et al., 2003; Beals and Hayes, 1995; Cui and Eriksen, 1996b; Gu and Schulz, 1991; Jaisi et al., 2009; Keith-Roach et al., 2003; Kumar et al., 2007), however little work has been conducted on the physical transport of the highly soluble pertechnetate oxyanion (TcO4-), in the subsurface. Current conceptual models do not explain the persistence and presence of technetium in deep vadose zone environments such as the Hanford site. In an oxic reducing environment with low organic content the residence time of technetium is the soil would be expected to be low, due to its low sorption and high solubility. Surprisingly, nearly 50 years following the release of contamination into the site, much of the element has persisted in the subsurface in the 200 Area. In these experiments we combined a variety of techniques to examine the mechanisms for physical and chemical retention and transport of technetium in Hanford sediments. We first determined the aqueous leachability with regard to sediment pore size in sediments containing technetium contamination from the 200 area of the Hanford Site. Using a series of sequential extractions, we then evaluated the mineral association of technetium. In a second series of tests we then used an Unsaturated Flow Apparatus (UFA) to evaluate breakthrough curve behavior and the impact of immobile domains on the transport and retention of technetium

  1. Ecotoxicity literature review of selected Hanford Site contaminants

    SciTech Connect

    Driver, C.J.

    1994-03-01

    Available information on the toxicity, food chain transport, and bioconcentration of several Hanford Site contaminants were reviewed. The contaminants included cesium-137, cobalt-60, europium, nitrate, plutonium, strontium-90, technetium, tritium, uranium, and chromium (III and VI). Toxicity and mobility in both aquatic and terrestrial systems were considered. For aquatic systems, considerable information was available on the chemical and/or radiological toxicity of most of the contaminants in invertebrate animals and fish. Little information was available on aquatic macrophyte response to the contaminants. Terrestrial animals such as waterfowl and amphibians that have high exposure potential in aquatic systems were also largely unrepresented in the toxicity literature. The preponderance of toxicity data for terrestrial biota was for laboratory mammals. Bioconcentration factors and transfer coefficients were obtained for primary producers and consumers in representative aquatic and terrestrial systems; however, little data were available for upper trophic level transfer, particularly for terrestrial predators. Food chain transport and toxicity information for the contaminants were generally lacking for desert or sage brush-steppe organisms, particularly plants and reptiles

  2. Diffusive release of uranium from contaminated sediments into capillary fringe pore water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M.; Harsh, James B.

    2012-10-01

    Despite remediation efforts at the former nuclear weapons facility at the Hanford site (Washington State), leaching of uranium (U) from contaminated sediments to the ground water persists at the Hanford 300 Area. Flooding of contaminated capillary fringe sediments due to seasonal changes in the Columbia River stage has been identified as a reason of continued U supply to ground water. We investigated the release of U from Hanford capillary fringe sediments to pore water. Contaminated Hanford sediments were packed into reservoirs of centrifugal filter devices and saturated with Columbia River water for 3 to 84 days at varying solution-to-solid ratios (1:3, 1:1, 5:1, 10:1, 25:1 mL:g). After specified times, samples were centrifuged to a gravimetric water content of 0.11 ± 0.06 g g-1. Within the first three days, there was an initial rapid release of 6-9% of total U from the sediments into the pore water, independent of the solution-to-solid ratio. After 14 days of reaction, however, the experiments with the narrowest solution-to-solid ratios (1:3 and 1:1 mL:g) showed a decline in dissolved U concentrations. The removal of U from the solution phase was accompanied by removal of Ca and HCO3-. Geochemist workbench simulations, conducted using measured solution concentrations from experiments, indicated that calcite could precipitate in the 1:3 solution-to-solid ratio experiment. After the rapid initial release in the first three days for the 5:1, 10:1, and 25:1 solution-to-solid ratio experiments, there was sustained release of U into the pore water. Up to 22% of total U was released on day 84 for the 25:1 solution-to-solid ratio reaction. This sustained release of U from the sediments had diffusion-limited kinetics.

  3. Inhibition Effect of Secondary Phosphate Mineral Precipitation on Uranium Release from Contaminated Sediments

    SciTech Connect

    Shi, Zhenqing; Liu, Chongxuan; Zachara, John M.; Wang, Zheming; Deng, Baolin

    2009-11-01

    The inhibitory effect of phosphate mineral precipitation on uranium release was evaluated using a U(VI)-contaminated sediment collected from the US Department of Energy (DOE) Hanford site. The sediment contained U(VI) that was associated with diffusion-limited intragrain regions within its mm-size granitic lithic fragments. The sediment was first treated to promote phosphate mineral precipitation in batch suspensions spiked with 1 and 50 mM aqueous phosphate, and calcium in a stoichiometric ratio of mineral hydroxyapatite. The phosphate-treated sediment was then leached to solubilize contaminant U(VI) in a column system using a synthetic groundwater that contained chemical components representative of Hanford groundwater. Phosphate treatment significantly decreased the extent of U(VI) release from the sediment. Within the experimental duration of about 200 pore volumes, the effluent U(VI) concentrations were consistently lower by over one and two orders of magnitude after the sediment was treated with 1 and 50 mM of phosphate, respectively. Measurements of solid phase U(VI) using various spectroscopes and chemical extraction of the sediment collectively indicated that the inhibition of U(VI) release from the sediment was caused by: 1) U(VI) adsorption to the secondary phosphate precipitates and 2) the transformation of initially present U(VI) mineral phases to less soluble forms.

  4. Dewatering of contaminated river sediments

    NASA Technical Reports Server (NTRS)

    Church, Ronald H.; Smith, Carl W.; Scheiner, Bernard J.

    1994-01-01

    Dewatering of slurries has been successfully accomplished by the proper use of polymers in flocculating the fine particulate matter suspended in mineral processing streams. The U.S. Bureau of Mines (USBM) entered into a cooperative research effort with the U.S. Army Corps of Engineers (Corps) for the purpose of testing and demonstrating the applicability of mining flocculation technology to dredging activities associated with the removal of sediments from navigable waterways. The Corps has the responsibility for maintaining the navigable waterways in the United States. Current technology relies primarily on dredging operations which excavate the material from the bottom of waterways. The Corps is testing new dredging technology which may reduce resuspension of sediments by the dredging operation. Pilot plant dredging equipment was tested by the Corps which generated larger quantities of water when compared to conventional equipment, such as the clam shell. The transportation of this 'excess' water adds to the cost of sediment removal. The process developed by the USBM consists of feed material from the barge being pumped through a 4-in line by a centrifugal pump and exiting through a 4-in PVC delivery system. A 1,000-gal fiberglass tank was used to mix the polymer concentrate. The polymer was pumped through a 1-in line using a variable speed progressive cavity pump and introduced to the 4-in feed line prior to passing through a 6-in by 2-ft static mixer. The polymer/feed slurry travels to the clarifying tank where the flocculated material settled to the bottom and allowed 'clean' water to exit the overflow. A pilot scale flocculation unit was operated on-site at the Corps' 'Confined Disposal Facility' in Buffalo, NY.

  5. Geochemical Characterization of Chromate Contamination in the 100 Area Vadose Zone at the Hanford Site - Part 2

    SciTech Connect

    Qafoku, Nikolla; Dresel, P. Evan; McKinley, James P.; Ilton, Eugene S.; Um, Wooyong; Resch, Charles T.; Kukkadapu, Ravi K.; Petersen, Scott W.

    2011-01-04

    At the Hanford Site, chromate was used throughout the 100 Areas (100-B, 100-C, 100-D/DR, 100-F, 100-H, and 100 K) as a corrosion inhibitor in reactor cooling water. Chromate was delivered in rail cars, tanker trucks, barrels, and local pipelines as dichromate granular solid or stock solution. In many occasions, chromate was inevitably discharged to surface or near-surface ground through spills during handling, pipeline leaks, or during disposal to cribs. The composition of the liquids that were discharged is not known and it is quite possible that Cr(VI) fate and transport in the contaminated sediments would be a function of the chemical composition of the waste fluids. The major objectives of this investigation which was limited in scope by the financial resources available, were to 1) determine the leaching characteristics of hexavalent chromium [Cr(VI)] from contaminated sediments collected from 100-D Area spill sites; 2) elucidate possible Cr(VI) mineral and/or chemical associations that may be responsible for Cr(VI) retention in the Hanford Site 100 Areas through the use of macroscopic leaching studies, and microscale characterization of contaminated sediments; and 3) provide information to construct a conceptual model of Cr(VI) geochemistry in the Hanford 100 Area vadose zone that can be used for developing options for environmental remediation. The information gathered from this research effort will help to further improve our understanding of Cr(VI) behavior in the vadose zone and will also help in accelerating the 100 Area Columbia River Corridor cleanup by providing valuable information to develop remedial action based on a fundamental understanding of Cr(VI) vadose zone geochemistry. A series of column experiments were conducted with contaminated sediments to study Cr(VI) desorption patterns. Column experiments used the field size fraction of the sediment samples and a simulated Hanford Site groundwater solution. Periodic stop flow events were applied to

  6. Nematode communities in contaminated river sediments.

    PubMed

    Heininger, Peter; Höss, Sebastian; Claus, Evelyn; Pelzer, Jürgen; Traunspurger, Walter

    2007-03-01

    Nematode communities of eight sites from three river catchments were investigated in terms of the genera composition, feeding types, and life-history strategists. The sampling sites showed a gradient of anthropogenic contamination with heavy metals and organic pollutants being important factors in differentiating the sites. Nematode community structure was related to sediment pollution and the hydro-morphological structure of the sampling sites. Heavily contaminated sites were characterized by communities with high relative abundances of omnivorous and predacious nematodes (Tobrilus, c-p 3; Mononchus, c-p 4), while sites with low to medium contamination were dominated by bacterivorous nematodes (Monhystera, Daptonema; c-p 2) or suction feeders (Dorylaimus, c-p 4). The relatively high Maturity Index values in the heavily polluted sites were surprising. Nematodes turned out to be a suitable organism group for monitoring sediment quality, with generic composition being the most accurate indicator for assessing differences in nematode community structure. PMID:16905227

  7. Desorption kinetics of radiocesium from subsurface sediments at Hanford Site, USA

    NASA Astrophysics Data System (ADS)

    Liu, Chongxuan; Zachara, John M.; Smith, Steve C.; McKinley, James P.; Ainsworth, Calvin C.

    2003-08-01

    The desorption of 137Cs + was investigated on sediments from the United States Hanford site. Pristine sediments and ones that were contaminated by the accidental release of alkaline 137Cs +-containing high level nuclear wastes (HLW, 2 × 10 6 to 6 × 10 7 pCi 137Cs +/g) were studied. The desorption of 137Cs + was measured in Na +, K +, Rb +, and NH 4+electrolytes of variable concentration and pH, and in presence of a strong Cs +-specific sorbent (self-assembled monolayer on a mesoporous support, SAMMS). 137Cs + desorption from the HLW-contaminated Hanford sediments exhibited two distinct phases: an initial instantaneous release followed by a slow kinetic process. The extent of 137Cs + desorption increased with increasing electrolyte concentration and followed a trend of Rb + ≥ K + > Na + at circumneutral pH. This trend followed the respective selectivities of these cations for the sediment. The extent and rate of 137Cs + desorption was influenced by surface armoring, intraparticle diffusion, and the collapse of edge-interlayer sites in solutions containing K +, Rb +, or NH 4+. Scanning electron microscopic analysis revealed HLW-induced precipitation of secondary aluminosilicates on the edges and basal planes of micaceous minerals that were primary Cs + sorbents. The removal of these precipitates by acidified ammonium oxalate extraction significantly increased the long-term desorption rate and extent. X-ray microprobe analyses of Cs +-sorbed micas showed that the 137Cs + distributed not only on mica edges, but also within internal channels parallel to the basal plane, implying intraparticle diffusive migration of 137Cs +. Controlled desorption experiments using Cs +-spiked pristine sediment indicated that the 137Cs + diffusion rate was fast in Na +-electrolyte, but much slower in the presence of K + or Rb +, suggesting an effect of edge-interlayer collapse. An intraparticle diffusion model coupled with a two-site cation exchange model was used to interpret the

  8. TOXICITY IDENTIFICATION EVALUATION (TIE) RESULTS FOR METAL CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Identification of contaminants in sediment is necessary for sound management decisions on sediment disposal, remediation, determination of ecological risk, and source identification. We have been developing sediment toxicity identification evaluation (TIE) techniques that allow ...

  9. Hanford Science and Technology Program: Reaction Transport Experiments Investigating the Migration of 137Cs in Sediments Beneath the Hanford SX Tank Farm

    SciTech Connect

    Carroll, S; Steefel, C; Zhao, P; Roberts, S

    2001-04-18

    Over one million gallons of high-level-waste with more than a million curies of {sup 137}Cs have leaked from Hanford tank farms to the sediments beneath the tanks. Early on, it was assumed that cesium migration would be limited because laboratory experiments had shown that cesium strongly sorbs to phyllosilicate minerals common in soils [1-5]. Additionally, minimal cesium desorption has been observed in contaminated Hanford sediments [6]. However, recent observations beneath the Hanford tank farms show that cesium has migrated to greater depths than expected [7]. Various explanations for enhanced cesium migration include (1) physical processes such as fast flow pathways or bypassing of exchange sites in immobile zones, and (2) chemical processes associated with the very high salt contents and high pH of the tank fluids. Ion exchange processes are clearly indicated in the depth profiles of {sup 137}Cs, and potassium, sodium, calcium, and nitrate (acting as a tracer) from the bore holes beneath tank SX-108 and tank SX-115. Below both tanks, cesium concentration peaks are retarded with respect to potassium and sodium concentration peaks. The importance of cation concentration on ion exchange is illustrated by comparing the sodium and tracer profiles beneath the tanks. Pore water with high sodium concentrations at SX-108 show little or no retardation of sodium, as is indicated by superimposed sodium and nitrate peaks. In contrast, at SX-115 sodium is significantly retarded relative to tracers (nitrate and Tc), presumably due to the lower sodium concentrations of the SX-115 leaks compared to SX-108 leaks. Calcium and magnesium form very distinct peaks at the leading edge of the sodium front under both SX-108 and SX-115. Observations such as these, led Zachara and his co-workers [8] to conduct a series of systematic cesium experiments over a wide range of cesium and salt concentrations to develop an ion exchange model that could be used to predict cesium migration

  10. Feasibility of supercritical CO{sub 2} extraction as a remediation technology for Hanford contaminated soils

    SciTech Connect

    Moody, T.E.; Krukonis, V.J.

    1994-12-31

    A technology used by the petroleum industry for separation and purification and the coffee industry for caffeine removal is being used by a Hanford scientist with the prospect of remediating organic contaminated Hanford soil. The process is known as Supercritical Fluid Extraction or SFE. Dr. Timothy Moody of the Westinghouse Hanford Company and the Phasex Corporation of Lawrence, Mass., have conducted successful bench-scale experiments at the 50g, 500g, and 5kg levels showing that SFE can remove various chemicals from large volumes of contaminated soil. The results indicate that organic contaminant removal from soil is much more efficient than the current industrial uses of SFE.

  11. Diffusive Release of Uranium from Contaminated Sediments into Capillary Fringe Pore Water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M.; Harsh, James B.

    2012-09-13

    We investigated the dynamics of U release between pore water fractions, during river stage changes from two contaminated capillary fringe sediments. Samples were from 7.0 m and 7.6 m below ground surface (bgs) in the Hanford 300 area. Sediments were packed into columns and saturated with Hanford groundwater for three to 84 days. After specified times, > 48 µm radius (calculated) sediment pores were drained, followed by draining pores to 15 µm radius. U release in the first two weeks was similar between sediments and pore sizes with a range of 4.4 to 5.6 µM U in the 14 day sample. The 7.0 m bgs sediment U declined in the larger pores to 0.22 µM at day 84, whereas the small pores released U to 6.7 µM at day 84. The 7.6 m bgs sediment released 1.4 µM on day 84, in the large pores, but continuously released U from the smaller pores (13.2 uM on day 84). The continuous release of U has resulted in a diffusion gradient from the smaller to larger pores. The observed differences in U pore-water concentrations between the two sediment samples were attributed to co-precipitation of U with carbonates. A mineral phase in the sediments was also identified as an U-carbonate species, similar to rutherfordine [UO2(CO3)].

  12. Isotopic Studies of Contaminant Transport at the Hanford Site,WA

    SciTech Connect

    Christensen, J.N.; Conrad, M.E.; DePaolo, D.J.; Dresel, P.E.

    2006-11-01

    Processes of fluid flow and chemical transport through thevadose zone can be characterized through the isotopic systematics ofnatural soils, minerals, pore fluids and groundwater. In thiscontribution, we first review our research using measured isotopicvariations, due both to natural and site related processes, of theelements H, O, N, Sr and U, to study the interconnection between vadosezone and groundwater contamination at the Hanford Site in south-centralWashington. We follow this brief review with a presentation of new datapertaining to vadose zone and groundwater contamination in the WMAT-TX-TY vicinity. Uranium (U) isotopic data for the C3832 core (WMA TX)indicates the involvement of processed natural U fuel, and links theobserved U contamination to the nearby single shelled tank TX-104. Thedata also precludes contamination from an early 1970 s TX-107 leak. Inthe case of the C4104 core (WMA T), the U isotopic data indicates amixture of processed natural and enriched U fuels consistent with themajor leak from T-106 in 1973. Uranium and Strontium isotopic data forthe cores also provides direct evidence for chemical interaction betweenhigh-pH waste fluid and sediment. Isotopic data for groundwater nitratecontamination in the vicinity of WMA-T strongly suggests high-level tankwaste (most likely from T-106) as the source of very high 99Tcconcentrations recently observed at the NE corner of WMAT.

  13. Canada Geese at the Hanford Site – Trends in Reproductive Success, Migration Patterns, and Contaminant Concentrations

    SciTech Connect

    Simmons, Mary Ann; Poston, Ted M.; Tiller, Brett L.; Stegen, Amanda; Hand, Kristine D.; Brandenberger, Jill M.

    2010-05-25

    Pacific Northwest National Laboratory (PNNL) has conducted several studies for the U.S. Department of Energy (DOE) to evaluate the status and condition of Canada geese on the Hanford Reach of the Columbia River. This report summarizes results of studies of Canada geese (Branta canadensis moffitti) at the Hanford Site dating back to the 1950s. Results include information on the nesting (reproductive) success of Canada geese using the Hanford Reach, review of the local and regional migration of this species using data from bird banding studies, and summary data describing monitoring and investigations of the accumulation of Hanford-derived and environmental contaminants by resident goose populations.

  14. Distribution of microbial biomass and the potential for anaerobic respiration in Hanford Site 300 Area subsurface sediment

    SciTech Connect

    Lin, Xueju; Kennedy, David W.; Peacock, Aaron D.; McKinley, James P.; Resch, Charles T.; Fredrickson, Jim K.; Konopka, Allan

    2012-02-01

    Subsurface sediments were recovered from a 52 m deep borehole cored in the 300 Area of the Hanford Site in southeastern Washington State to assess the potential for biogeochemical transformation of radionuclide contaminants. Microbial analyses were made on 17 sediment samples traversing multiple geological units: the oxic coarse-grained Hanford formation (9-17.4 m), the oxic fine-grained upper Ringold Formation (17.7-18.1 m), and the reduced Ringold Formation (18.3-52m). Microbial biomass (measured as phospholipid) ranged from 7-974 pmols per g in discrete samples, with the highest numbers found in the Hanford formation. On average, strata below 17.4 m had 13-fold less biomass than those from shallower strata. The nosZ gene encoding nitrous oxide reductase had an abundance of 5-17% relative to total 16S rRNA genes below 18.3 m and <5% above 18.1 m. Most nosZ sequences were affiliated with Ochrobactrum anthropi (97% sequence similarity) or had a nearest neighbor of Achromobacter xylosoxidans (90% similarity). Passive multilevel sampling of groundwater geochemistry demonstrated a redox gradient in the 1.5 m region between the Hanford-Ringold formation contact and the Ringold oxic-anoxic interface. Within this zone, copies of the dsrA gene and Geobacteraceae had the highest relative abundance. The majority of dsrA genes detected near the interface were related to Desulfotomaculum sp.. These analyses indicate that the region just below the contact between the Hanford and Ringold formations is a zone of active biogeochemical redox cycling.

  15. A Long-Term Strategic Plan for Hanford Sediment Physical Property and Vadose Zone Hydraulic Parameter Databases

    SciTech Connect

    Rockhold, Mark L.; Last, George V.; Middleton, Lisa A.

    2009-09-30

    Physical property data and unsaturated hydraulic parameters are critical input for analytic and numerical models used to predict transport and fate of contaminants in variably saturated porous media and to assess and execute remediation alternatives. The Remediation Decision Support (RDS) project, managed by the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE) and the CH2M Hill Plateau Remediation Company (CHPRC), has been compiling physical and hydraulic property data and parameters to support risk analyses and waste management decisions at Hanford. Efforts have been initiated to transfer sediment physical property data and vadose zone hydraulic parameters to CHPRC for inclusion in HEIS-Geo, a new instance of the Hanford Environmental Information System database that is being developed for borehole geologic data. This report describes these efforts and a strategic plan for continued updating and improvement of these datasets.

  16. Radioiodine sorption/desorption and speciation transformation by subsurface sediments from the Hanford Site

    SciTech Connect

    Xu, Chen; Kaplan, Daniel I.; Zhang, Saijin; Athon, Matthew; Ho, Yi-Fang; Li, Hsiu-Ping; Yeager, Chris; Schwehr, Kathy; Grandbois, Russell; Wellman, Dawn M.; Santschi, Peter H.

    2015-01-01

    During the last few decades, considerable research efforts have been extended to identify more effective remediation treatment technologies to lower the 129I concentrations to below federal drinking water standards at the Hanford Site (Richland, USA). Few studies have taken iodate into consideration, though recently iodate, instead of iodide, was identified as the major species in the groundwater of 200-West Area within the Hanford Site. The objective of this study was thus to quantify and understand aqueous radioiodine species transformations and uptake by three sediments collected from the semiarid, carbonate-rich environment of the Hanford subsurface. All three sediments reduced iodate (IO-) to iodide (I-), but the loamy-sand sediment reduced more IO3- (100% reduced within 7 days) than the two sand-textured sediments (~20% reduced after 28 days). No dissolved organo-iodine species were observed in any of these studies.

  17. Sediment contaminant surveillance in Milford Haven Waterway.

    PubMed

    Little, D I; Bullimore, B; Galperin, Y; Langston, W J

    2016-01-01

    Sediment contaminants were monitored in Milford Haven Waterway (MHW) since 1978 (hydrocarbons) and 1982 (metals), with the aim of providing surveillance of environmental quality in one of the UK's busiest oil and gas ports. This aim is particularly important during and after large-scale investment in liquefied natural gas (LNG) facilities. However, the methods inevitably have changed over the years, compounding the difficulties of coordinating sampling and analytical programmes. After a review by the MHW Environmental Surveillance Group (MHWESG), sediment hydrocarbon chemistry was investigated in detail in 2010. Natural Resources Wales (NRW) contributed their MHW data for 2007 and 2012, collected to assess the condition of the Special Area of Conservation (SAC) designated under the European Union Habitats Directive. Datasets during 2007-2012 have thus been more comparable. The results showed conclusively that a MHW-wide peak in concentrations of sediment polycyclic aromatic hydrocarbons (PAHs), metals and other contaminants occurred in late 2007. This was corroborated by independent annual monitoring at one centrally located station with peaks in early 2008 and 2011. The spatial and temporal patterns of recovery from the 2007 peak, shown by MHW-wide surveys in 2010 and 2012, indicate several probable causes of contaminant trends, as follows: atmospheric deposition, catchment runoff, sediment resuspension from dredging, and construction of two LNG terminals and a power station. Adverse biological effects predictable in 2007 using international sediment quality guidelines were independently tested by data from monitoring schemes of more than a decade duration in MHW (starfish, limpets) and in the wider SAC (grey seals). Although not proving cause and effect, many of these potential biological receptors showed a simultaneous negative response to the elevated 2007 contamination following intense dredging activity in 2006. Wetland bird counts were typically at a peak in

  18. Sediment contaminant surveillance in Milford Haven Waterway.

    PubMed

    Little, D I; Bullimore, B; Galperin, Y; Langston, W J

    2016-01-01

    Sediment contaminants were monitored in Milford Haven Waterway (MHW) since 1978 (hydrocarbons) and 1982 (metals), with the aim of providing surveillance of environmental quality in one of the UK's busiest oil and gas ports. This aim is particularly important during and after large-scale investment in liquefied natural gas (LNG) facilities. However, the methods inevitably have changed over the years, compounding the difficulties of coordinating sampling and analytical programmes. After a review by the MHW Environmental Surveillance Group (MHWESG), sediment hydrocarbon chemistry was investigated in detail in 2010. Natural Resources Wales (NRW) contributed their MHW data for 2007 and 2012, collected to assess the condition of the Special Area of Conservation (SAC) designated under the European Union Habitats Directive. Datasets during 2007-2012 have thus been more comparable. The results showed conclusively that a MHW-wide peak in concentrations of sediment polycyclic aromatic hydrocarbons (PAHs), metals and other contaminants occurred in late 2007. This was corroborated by independent annual monitoring at one centrally located station with peaks in early 2008 and 2011. The spatial and temporal patterns of recovery from the 2007 peak, shown by MHW-wide surveys in 2010 and 2012, indicate several probable causes of contaminant trends, as follows: atmospheric deposition, catchment runoff, sediment resuspension from dredging, and construction of two LNG terminals and a power station. Adverse biological effects predictable in 2007 using international sediment quality guidelines were independently tested by data from monitoring schemes of more than a decade duration in MHW (starfish, limpets) and in the wider SAC (grey seals). Although not proving cause and effect, many of these potential biological receptors showed a simultaneous negative response to the elevated 2007 contamination following intense dredging activity in 2006. Wetland bird counts were typically at a peak in

  19. Field Evidence for Strong Chemical Separation of Contaminants in the Hanford Vadose Zone

    SciTech Connect

    Conrad, Mark E.; Depaolo, D. J.; Maher, Katharine; Gee, Glendon W.; Ward, Anderson L.

    2007-11-01

    Water and chemical transport from a point source within vadose zone sediments at the Hanford Site in Washington State were examined with a leak test consisting of five 3800-L aliquots of water released at 4.5-m depth every week over a 4-wk period. The third aliquot contained bromide, D2O, and 87Sr. Movement of the tracers was monitored for 9 mo by measuring pore water compositions of samples from boreholes drilled 2 to 8 m from the injection point. Graded sedimentary layers acting as natural capillary barriers caused significant lateral spreading of the leak water. Shortly after injections were completed, D2O was found at the 9- to 11-m depth at levels in excess of 50% of the tracer aliquot concentration, while sediment layers with elevated water content at the 6- to 7-m depth had less than 3% of the D2O tracer concentration, suggesting deep penetration of the D2O tracer and limited mixing between different aliquots of leak fluids. Initially, high bromide concentrations decreased more rapidly over time than D2O, suggesting enhanced transport of bromide due to anion exclusion. No significant increase in 87Sr was detected in the sampled pore water, indicating strong retardation of Sr by the sediments. These results highlight some of the processes strongly affecting chemical transport in the vadose zone and demonstrate the significant separation of contaminant plumes that can occur.

  20. Contaminants in Chesapeake Bay sediments, 1984-1991

    SciTech Connect

    Eskin, R.A.; Rowland, K.H.; Alegre, D.Y.

    1996-05-01

    This report presents data on sediment chemical contaminant concentrations in the Chesapeake Bay and its tidal tributaries collected between 1984 and 1991. The majority of this data collection was coordinated by Maryland and Virginia with support from the Chesapeake Bay Program. The primary objectives of this report are to describe the spatial patterns in the distribution of sediment chemical contaminants in Chesapeake Bay to sediment quality guidelines in order to identify areas where sediment chemical contaminants may adversely impact aquatic biota.

  1. Past Radioactive Particle Contamination in the Columbia River at the Hanford Site, USA

    SciTech Connect

    Poston, Ted M.; Peterson, Robert E.; Cooper, Andrew T.

    2007-08-24

    The Hanford Site was originally established in 1943 as part of the World War II Manhattan Project to produce a nuclear weapon. During the Site’s early history, eight single-pass reactors were constructed along the “Hanford Reach” of the Columbia River to produce plutonium. Reactor coolant effluent was held temporarily in retention basins so that short-lived activation products and temperature could dissipate before discharge to the river. Reactor components included valves and pumps constructed with Stellite, an alloy containing high levels of cobalt and other metals. Neutron activation of these components produced cobalt-60. As these components aged, they deteriorated and released radioactive particles into the liquid effluent. Over the 26 years of reactor operations, relatively small numbers of these particles were released to the Columbia River along with the liquid discharges, and the particles were deposited in sediment along the shoreline and on islands. In 1976, portions of the Hanford Reach were opened for public access and the presence of these radioactive cobalt-60 particles became a concern for public exposure. A survey conducted in 1979 determined that the particles were small, with a diameter of approximately 0.1 mm, and their activity level was estimated to be between 63 and 890 GBq. Dose rates from the particles ranged from 1 to 14 μGray/hr. Fourteen particles were collected during the 1979 survey and subsequent monitoring and particle clean-up campaigns continued during the 1980s and 1990s. The presence of radioactive particles in the river environment was a continuing concern as cleanup of the Hanford Site accelerated during the 1990s. Principal issues included: 1) Site management response to the presence of radioactive particles in the Columbia River, 2) methods to monitor this contamination, 3) stakeholder concerns, and 4) anti-nuclear activist intervention. Reducing ecological and human health risk caused by contamination is a major focus

  2. Diffusive release of uranium from contaminated sediments into capillary fringe pore water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M; Harsh, James B.

    2012-01-01

    Despite remediation efforts at the former nuclear weapons facility, leaching of uranium (U) from contaminated sediments to the ground water persists at the Hanford site 300 Area. Flooding of contaminated capillary fringe sediments due to seasonal changes in the Columbia River stage has been identified as a source for U supply to ground water. We investigated U release from Hanford capillary fringe sediments by packing sediments into reservoirs of centrifugal filter devices and saturated with Columbia River water for 3 to 84 days at varying solution-to-solid ratios. After specified times, samples were centrifuged. Within the first three days, there was an initial rapid release of 6-9% of total U, independent of the solution-to-solid ratio. After 14 days of reaction, however, the experiments with the narrowest solution-to-solid ratios showed a decline in dissolved U concentrations. The removal of U from the solution phase was accompanied by removal of Ca and HCO3-. Geochemical modeling indicated that calcite could precipitate in the narrowest solution-to-solid ratio experiment. After the rapid initial release in the first three days for the wide solution-to-solid ratio experiments, there was sustained release of U into the pore water. This sustained release of U from the sediments had diffusion-limited kinetics.

  3. Vertical Extent of 100 Area Vadose Zone Contamination of Metals at the Hanford Site

    NASA Astrophysics Data System (ADS)

    Khaleel, R.; Mehta, S.

    2012-12-01

    The 100 Area is part of the U.S. Department of Energy Hanford Site in southeastern Washington and borders the Columbia River. The primary sources of contamination in the area are associated with the operation of nine former production reactors, the last one shutting down in 1988. The area is undergoing a CERCLA remedial investigation (RI) that will provide data to support final cleanup decisions. During reactor operations, cooling water contaminated with radioactive and hazardous chemicals was discharged to both the adjacent Columbia River and infiltration cribs and trenches. Contaminated solid wastes were disposed of in burial grounds; the estimated Lead-Cadmium used as "reactor poison" and disposed of in 100 Area burial grounds is 1103 metric tons, of which up to 1059 metric tons are Lead and 44 metric tons are Cadmium. We summarize vadose zone site characterization data for the recently drilled boreholes, including the vertical distribution of concentration profiles for metals (i.e., Lead, Arsenic and Mercury) under the near neutral pH and oxygenated conditions. The deep borehole measurements targeted in the RI work plan were identified with a bias towards locating contaminants throughout the vadose zone and targeted areas at or near the waste sites; i.e., the drilling as well as the sampling was biased towards capturing contamination within the "hot spots." Unlike non-reactive contaminants such as tritium, Arsenic, Mercury and Lead are known to have a higher distribution coefficient (Kd), expected to be relatively immobile, and have a long residence time within the vadose zone. However, a number of sediment samples located close to the water table exceed the background concentrations for Lead and Arsenic. Three conceptual models are postulated to explain the deeper than expected penetration for the metals.

  4. Inhibited Release of Mobile Contaminants from Hanford Tank Residual Waste

    SciTech Connect

    Cantrell, Kirk J.; Heald, Steve M.; Arey, Bruce W.; Lindberg, Michael J.

    2011-03-03

    Investigations of contaminant release from Hanford Site tank residual waste have indicated that in some cases certain contaminants of interest (Tc and Cr) exhibit inhibited release. The percentage of Tc that dissolved from residual waste from tanks 241-C-103, 241-C-106, 241-C-202, and 241-C-203 ranged from approximately 6% to 10%. The percent leachable Cr from residual waste from tanks C-103, C 202, and C-203 ranged from approximately 1.1% to 44%. Solid phase characterization results indicate that the recalcitrant forms of these contaminants are associated with iron oxides. X-ray absorption near edge structure analysis of Tc and Cr in residual waste indicates that these contaminants occur in Fe oxide particles as their lower, less soluble oxidation states [Tc(IV) and Cr(III)]. The form of these contaminants is likely as oxides or hydroxides incorporated within the structure of the Fe oxide. Leaching behavior of U from tank residual waste was studied using deionized water, and CaCO3 and Ca(OH)2 saturated solutions as leachants. The release behavior of U from tank residual waste is complex. Initial U concentrations in water and CaCO3 leachants are high due to residual amounts of the highly soluble U mineral cejkaite. As leaching and dilution occur NaUO2PO4 {center_dot} xH2O, Na2U2O7(am) and schoepite (or a similar phase) become the solubility controlling phases for U. In the case of the Ca(OH)2 leachant, U release from tank residual waste is dramatically reduced. Thermodynamic modeling indicates that the solubility of CaUO4(c) controls release of U from residual waste in the Ca(OH)2 leachants. It is assumed the solubility controlling phase is actually a hydrated version of CaUO4 with a variable water content ranging from CaUO4 to CaUO4 {center_dot} (H2O). The critically reviewed value for CaUO4(c) (log KSP0 = 15.94) produced good agreement with our experimental data for the Ca(OH)2 leachates.

  5. Characterizing the Catalytic Potential of Deinococcus, Arthrobacter and other Robust Bacteria in Contaminated Subsurface Environments of the Hanford Site

    SciTech Connect

    Daly, Michael J.

    2005-06-01

    Natural selection in highly radioactive waste sites may yield bacteria with favorable bioremediating characteristics. However, until recently the microbial ecology of such environments has remained unexplored because of the high costs and technical complexities associated with extracting and characterizing samples from such sites. We have examined the bacterial ecology within radioactive sediments from a high-level nuclear waste plume in the vadose zone on the DOE?s Hanford Site in south-central Washington state (Fredrickson et al, 2004). Manganese-dependent, radiation resistant bacteria have been isolated from this contaminated site including the highly Mn-dependent Deinococcus and Arthrobacter spp.

  6. SEDIMENTS: A RESERVOIR OF HISTORIC CONTAMINATION OF THE ENVIRONMENT

    EPA Science Inventory

    Sediments contain contaminants derived from past activities that seriously degraded the environment.

    During low water, sediments are subject to natural erosion or removal for navigation.

    Erosion or dredging of sediment will release contaminants into the environment ...

  7. Field Summary Report for Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington, Collection of Surface Water, River Sediments, and Island Soils

    SciTech Connect

    L. C. Hulstrom

    2009-09-28

    This report has been prepared in support of the remedial investigation of Hanford Site Releases to the Columbia River and describes the 2008/2009 data collection efforts. This report documents field activities associated with collection of sediment, river water, and soil in and adjacent to the Columbia River near the Hanford Site and in nearby tributaries.

  8. Toxicity of lead-contaminated sediment to mallards

    USGS Publications Warehouse

    Heinz, G.H.; Hoffman, D.J.; Sileo, L.; Audet, D.J.; LeCaptain, L.J.

    1999-01-01

    Because consumption of lead-contaminated sediment has been suspected as the cause of waterfowl mortality in the Coeur d?Alene River basin in Idaho, we studied the bioavailability and toxicity of this sediment to mallards (Anas platyrhynchos). In experiment 1, one of 10 adult male mallards died when fed a pelleted commercial duck diet that contained 24% lead-contaminated sediment (with 3,400 μg/g lead in the sediment). Protoporphyrin levels in the blood increased as the percentage of lead-contaminated sediment in the diet increased. Birds fed 24% lead-contaminated sediment exhibited atrophy of the breast muscles, green staining of the feathers around the vent, viscous bile, green staining of the gizzard lining, and renal tubular intranuclear inclusion bodies. Mallards fed 24% lead-contaminated sediment had means of 6.1 μg/g of lead in the blood and 28 μg/g in the liver (wet-weight basis) and 1,660 μg/g in the feces (dry-weight basis). In experiment 2, we raised the dietary concentration of the lead-contaminated sediment to 48%, but only about 20% sediment was actually ingested due to food washing by the birds. Protoporphyrin levels were elevated in the lead-exposed birds, and all of the mallards fed 48% lead-contaminated sediment had renal tubular intranuclear inclusion bodies. The concentrations of lead in the liver were 9.1 μg/g for mallards fed 24% lead-contaminated sediment and 16 μg/g for mallards fed 48% lead-contaminated sediment. In experiment 3, four of five mallards died when fed a ground corn diet containing 24% lead-contaminated sediment (with 4,000 μg/g lead in this sample of sediment), but none died when the 24% lead-contaminated sediment was mixed into a nutritionally balanced commercial duck diet; estimated actual ingestion rates for sediment were 14% and 17% for the corn and commercial diets. Lead exposure caused elevations in protoporphyrin, and four of the five mallards fed 24% lead-contaminated sediment in a commercial diet and all five

  9. Compost treatment of contaminated pond sediment

    SciTech Connect

    Francis, M.; Gukert, D. |

    1995-12-31

    This paper summarizes an experiment involving compost treatment of pond sediment contaminated with hydrocarbons. Experimental variables included the size, shape, and aeration of the compost pile. Pile temperature measurements and hydrocarbon analyses were made periodically. Temperatures in the pyramid shaped compost piles rose quickly and remained elevated above ambient for about one month; during this period, hydrocarbon loss from the piles was greatest. The flat pile did not show elevated temperatures at any time, and total hydrocarbon losses by volatilization were 19.1 g. Total losses from the passively aerated pile were 1.02 g, while the actively aerated pile had losses of 0.08 g. Individual identified component compounds in the sediment included polycyclic aromatic hydrocarbons (PAHs). Final levels were in the 2 to 20 ppM range compared to 100 to 400 ppM in the original sediment. Composting removed PAH components and other light organics, and the composted material can be stored onsite or landfilled without leaching concerns.

  10. Unit environmental transport assessment of contaminants from Hanford`s past-practice waste sites. Hanford Remedial Action Environmental Impact Statement

    SciTech Connect

    Whelan, G.; Buck, J.W.; Castleton, K.J.

    1995-06-01

    The US Department of Energy, Richland Operations Office (DOE-RL) contracted Pacific Northwest Laboratory (PNL) to provide support to Advanced Sciences, Incorporated (ASI) in implementing tile regional no-action risk assessment in the Hanford Remedial Action Environmental Impact Statement. Researchers at PNL were charged with developing unit concentrations for soil, groundwater, surface water, and air at multiple locations within an 80-km radius from the center of tile Hanford installation. Using the Multimedia Environmental Pollutant Assessment System (MEPAS), PNL simulated (1) a unit release of one ci for each radionuclide and one kg for each chemical from contaminated soils and ponded sites, (2) transport of the contaminants in and through various environmental media and (3) exposure/risk of four exposure scenarios, outlined by the Hanford Site Baseline Remedial Action Methodology. These four scenarios include residential, recreational, industrial, and agricultural exposures. Spacially and temporally distributed environmental concentrations based on unit releases of radionuclides and chemicals were supported to ASI in support of the HRA-EIS. Risk for the four exposure scenarios, based on unit environment concentrations in air, water, and soil. were also supplied to ASI. This report outlines the procedure that was used to implement the unit transport portion of the HRA-EIS baseline risk assessment. Deliverables include unit groundwater, surface water, air, and soil concentrations at multiple locations within an 80-km radius from the center of the Hanford installation.

  11. Suspended sediment and sediment-associated contaminants in San Francisco Bay

    USGS Publications Warehouse

    Schoellhamer, D.H.; Mumley, T.E.; Leatherbarrow, J.E.

    2007-01-01

    Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transport has improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls. ?? 2007 Elsevier Inc. All rights reserved.

  12. Air emissions from exposed contaminated sediments and dredged material

    SciTech Connect

    Valsaraj, K.T.; Ravikrishna, R.; Reible, D.D.; Thibodeaux, L.J.; Choy, B.; Price, C.B.; Brannon, J.M.; Myers, T.E.; Yost, S.

    1999-01-01

    The sediment-to-air fluxes of two polycyclic aromatic hydrocarbons (phenanthrene and pyrene) and a heterocyclic aromatic hydrocarbon (dibenzofuran) from a laboratory-contaminated sediment and those of three polycyclic aromatic hydrocarbons (naphthalene, phenanthrene, and pyrene) from three field sediments were investigated in experimental microcosms. The flux was dependent on the sediment moisture content, air-filled porosity, and the relative humidity of the air flowing over the sediment surface. The mathematical model predictions of flux from the laboratory-spiked sediment agreed with observed values. The fluxes of compounds with higher hydrophobicity were more air-side resistance controlled. Conspicuous differences were observed between the fluxes from the laboratory-spiked and two of the three field sediments. Two field sediments showed dramatic increases in mass-transfer resistances with increasing exposure time and had significant fractions of oil and grease. The proposed mathematical model was inadequate for predicting the flux from the latter field sediments. Sediment reworking enhanced the fluxes from the field sediments due to exposure of fresh solids to the air. Variations in flux from the lab-spiked sediment as a result of change in air relative humidity were due to differences in retardation of chemicals on a dry or wet surface sediment. High moisture in the air over the dry sediment increased the competition for sorption sites between water and contaminant and increased the contaminant flux.

  13. SOIL DESICCATION TECHNIQUES STRATEGIES FOR IMMOBILIZATION OF DEEP VADOSE CONTAMINANTS AT THE HANFORD CENTRAL PLATEAU

    SciTech Connect

    BENECKE MW; CHRONISTER GB; TRUEX MJ

    2012-01-30

    Deep vadose zone contamination poses some of the most difficult remediation challenges for the protection of groundwater at the Hanford Site where processes and technologies are being developed and tested for use in the on-going effort to remediate mobile contamination in the deep vadose zone, the area deep beneath the surface. Historically, contaminants were discharged to the soil along with significant amounts of water, which continues to drive contaminants deeper in the vadose zone toward groundwater. Soil desiccation is a potential in situ remedial technology well suited for the arid conditions and the thick vadose zone at the Hanford Site. Desiccation techniques could reduce the advance of contaminants by removing the pore water to slow the rate of contaminants movement toward groundwater. Desiccation technologies have the potential to halt or slow the advance of contaminants in unsaturated systems, as well as aid in reduction of contaminants from these same areas. Besides reducing the water flux, desiccation also establishes capillary breaks that would require extensive rewetting to resume pore water transport. More importantly, these techniques have widespread application, whether the need is to isolate radio nuclides or address chemical contaminant issues. Three different desiccation techniques are currently being studied at Hanford.

  14. Mixture design and treatment methods for recycling contaminated sediment.

    PubMed

    Wang, Lei; Kwok, June S H; Tsang, Daniel C W; Poon, Chi-Sun

    2015-01-01

    Conventional marine disposal of contaminated sediment presents significant financial and environmental burden. This study aimed to recycle the contaminated sediment by assessing the roles and integration of binder formulation, sediment pretreatment, curing method, and waste inclusion in stabilization/solidification. The results demonstrated that the 28-d compressive strength of sediment blocks produced with coal fly ash and lime partially replacing cement at a binder-to-sediment ratio of 3:7 could be used as fill materials for construction. The X-ray diffraction analysis revealed that hydration products (calcium hydroxide) were difficult to form at high sediment content. Thermal pretreatment of sediment removed 90% of indigenous organic matter, significantly increased the compressive strength, and enabled reuse as non-load-bearing masonry units. Besides, 2-h CO2 curing accelerated early-stage carbonation inside the porous structure, sequestered 5.6% of CO2 (by weight) in the sediment blocks, and acquired strength comparable to 7-d curing. Thermogravimetric analysis indicated substantial weight loss corresponding to decomposition of poorly and well crystalline calcium carbonate. Moreover, partial replacement of contaminated sediment by various granular waste materials notably augmented the strength of sediment blocks. The metal leachability of sediment blocks was minimal and acceptable for reuse. These results suggest that contaminated sediment should be viewed as useful resources.

  15. Incorporating Contaminant Bioavailability into Sediment Quality Assessment Frameworks

    EPA Science Inventory

    The recently adopted sediment quality assessment framework for evaluating bay and estuarine sediments in the State of California incorporates bulk sediment chemistry as a key line of evidence(LOE) but does not address the bioavailability of measured contaminants. Thus, the chemis...

  16. Mixture design and treatment methods for recycling contaminated sediment.

    PubMed

    Wang, Lei; Kwok, June S H; Tsang, Daniel C W; Poon, Chi-Sun

    2015-01-01

    Conventional marine disposal of contaminated sediment presents significant financial and environmental burden. This study aimed to recycle the contaminated sediment by assessing the roles and integration of binder formulation, sediment pretreatment, curing method, and waste inclusion in stabilization/solidification. The results demonstrated that the 28-d compressive strength of sediment blocks produced with coal fly ash and lime partially replacing cement at a binder-to-sediment ratio of 3:7 could be used as fill materials for construction. The X-ray diffraction analysis revealed that hydration products (calcium hydroxide) were difficult to form at high sediment content. Thermal pretreatment of sediment removed 90% of indigenous organic matter, significantly increased the compressive strength, and enabled reuse as non-load-bearing masonry units. Besides, 2-h CO2 curing accelerated early-stage carbonation inside the porous structure, sequestered 5.6% of CO2 (by weight) in the sediment blocks, and acquired strength comparable to 7-d curing. Thermogravimetric analysis indicated substantial weight loss corresponding to decomposition of poorly and well crystalline calcium carbonate. Moreover, partial replacement of contaminated sediment by various granular waste materials notably augmented the strength of sediment blocks. The metal leachability of sediment blocks was minimal and acceptable for reuse. These results suggest that contaminated sediment should be viewed as useful resources. PMID:25464304

  17. A Systematic Approach for Developing Conceptual Models of Contaminant Transport at the Hanford Site

    NASA Astrophysics Data System (ADS)

    Murray, C. J.; Last, G. V.; Rohay, V. J.; Schelling, F. J.; Hildebrand, R. D.; Morse, J. G.

    2004-12-01

    The U.S. Department of Energy (DOE) faces many decisions regarding future remedial actions and waste disposal at the Hanford Site in southeast Washington State. To support these decisions, DOE recognized the need for a comprehensive and systematic approach to developing and documenting complete, consistent, and defensible conceptual models of contaminant release and migration. After reviewing existing conceptual model development methodologies that might be applicable to environmental assessments at the Hanford Site, DOE initiated efforts to adapt and implement the Features, Events, and Processes (FEP) methodology developed for use in performance assessments of nuclear waste disposal systems by NIREX. In adapting this methodology for use in the environmental assessments at Hanford, the international list of FEPs, compiled from nuclear waste disposal programs, was evaluated to develop a list of potentially relevant Hanford-specific FEPs. The international nuclear waste programs focus on deep geologic disposal while waste disposal at the Hanford Site involves burial in shallow unconsolidated geologic deposits. Thus, a graphical tool called the Process Relationship Diagram (PRD) was created to assist in identifying the international FEPs and additional factors that are relevant to Hanford, and to illustrate the relationships among these factors. The PRD is similar in form and function to the Master Directed Diagram used by NIREX to provide a visual and systematic structure for the FEP methodology. Adaptation of this approach is showing promise in facilitating the development of conceptual models and selection of relevant factors to be incorporated into environmental uncertainty assessments for the Hanford Site.

  18. Sediment toxicity and benthic communities in mildly contaminated mudflats

    SciTech Connect

    Nipper, M.G.; Roper, D.S.; Williams, E.K.; Martin, M.L.; Van Dam, L.F.; Mills, G.N.

    1998-03-01

    Sediment physicochemical characteristics, benthic community structure, and toxicity were measured at reference and contaminated intertidal mudflats around the North Island of New Zealand. Chronic whole-sediment toxicity tests were conducted with the estuarine amphipod, Chaetocorophium lucasi and the marine bivalve, Macomona lilana, and pore-water toxicity tests were conducted with embryos of the echinoid, Fellaster zelandiae. Although concentrations of organic chemicals and heavy metals were up to several orders of magnitude higher at the sites considered to be contaminated, levels of contamination were relatively low compared to internationally based sediment quality guidelines. Although no pronounced difference was found in benthic community structure between reference and contaminated sites, multivariate analysis indicated that natural sediment characteristics and factors related to contamination may have been affecting community structure. Although benthic effects caused by present levels of contamination are not yet dramatic, subtle changes in community structure related to pollution may be occurring. The two whole-sediment and the pore-water toxicity tests presented different response patterns. Growth of C. lucasi and M. liliana was a less sensitive endpoint than survival. None of the three toxicity tests responded more strongly to the contaminated than to the reference sites, that is, neither natural-sediment and pore-water characteristics nor unmeasured contaminants affected the test organisms. It is possible that sediment collection and handling may have induced chemical changes, confounding interpretation of toxicity tests.

  19. TOOLS FOR ASSESSING MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Management of contaminated sediments poses many challenges due to varied contaminants and volumes of sediments to manage. dredging, capping, and monitored natural recovery (MNR) are the primary approaches at this time for managing contaminated sediment risks. Understanding how we...

  20. Innovative Capping Technology To Prevent The Migration of Toxic Chemicals From Contaminated Sediments

    EPA Science Inventory

    Capping is a common strategy for decreasing the risk associated with contaminated sediments in lakes and streams. Historically, caps have been designed to physically isolate contaminated sediments and prevent the transport of contaminants from sediments into the water above them...

  1. NHEERL CONTAMINATED SEDIMENT RESEARCH MULTI-YEAR IMPLEMENTATION PLAN (2005)

    EPA Science Inventory

    ORD has developed a multi-year plan (MYP) called the Contaminated Sites MYP to address the research needs of EPA's Office of Superfund Remediation and Technology Innovation (OSRTI). One of the long-term goals of the Contaminated Sites MYP relates to contaminated sediments, and t...

  2. Regulating contaminated sediments in aquatic environments: A hydrologic perspective

    NASA Astrophysics Data System (ADS)

    Marcus, W. Andrew

    1989-11-01

    A number of state and federal agencies are presently attempting to develop management strategies for contaminated aquatic sediments. Until now, research and debate on sediment guidelines and regulations has focused almost exclusively on biological and chemical techniques for determining when sediments pose an environmental risk. Hydrologic factors must also be considered, however, if these biochemically based techniques for establishing sediment quality standards are to be feasible. Hydrologic issues that need to be addressed include how to define the boundaries of the aquatic environment, the scope of sediment regulations in ephemeral waters, regulations and sampling procedures in heterogeneous sediments, and timing of samples for monitoring and enforcement purposes

  3. Vadose zone characterization of highly radioactive contaminated soil at the Hanford Site

    SciTech Connect

    Buckmaster, M.A.

    1993-05-01

    The Hanford Site in south-central Washington State contains over 1500 identified waste sites and numerous groundwater plumes that will be characterized and remediated over the next 30 years. As a result of the Hanford Federal Facility Agreement and Consent Order, the US Department of Energy has initiated a remedial investigation/feasibility study at the 200-BP-1 operable unit. The 200-BP-1 remedial investigation is the first Comprehensive Environmental Response, Compensation, and Liability Act of 1980 investigation on the Hanford Site that involves drilling into highly radioactive and chemically contaminated soils. The initial phase of site characterization was designed to assess the nature and extent of contamination associated with the source waste site within the 200-BP-1 operable unit. Characterization activities consisted of drilling and sampling the waste site, chemical and physical analysis of samples, and development of a conceptual vadose zone model. Predicted modeling concentrations compared favorably to analytical data collected during the initial characterization activities.

  4. Strontium and cesium release mechanisms during unsaturated flow through waste-weathered Hanford sediments

    SciTech Connect

    Chang, Hyun-Shik; Um, Wooyong; Rod, Kenton A.; Serne, R. Jeffrey; Thompson, Aaron; Perdrial, Nicolas; Steefel, Carl I.; Chorover, Jon

    2011-10-01

    Leaching behavior of Sr and Cs in the vadose zone of Hanford site (WA, USA) was studied with laboratory-weathered sediments mimicking realistic conditions beneath the leaking radioactive waste storage tanks. Unsaturated column leaching experiments were conducted using background Hanford pore water focused on first 200 pore volumes. The weathered sediments were prepared by 6 months reaction with a synthetic Hanford tank waste leachate containing Sr and Cs (10-5 and 10-3 molal representative of LO- and HI-sediment, respectively) as surrogates for 90Sr and 137Cs. The mineral composition of the weathered sediments showed that zeolite (chabazite-type) and feldspathoid (sodalite-type) were the major byproducts but different contents depending on the weathering conditions. Reactive transport modeling indicated that Cs leaching was controlled by ion-exchange, while Sr release was affected primarily by dissolution of the secondary minerals. The later release of K, Al, and Si from the HI-column indicated the additional dissolution of a more crystalline mineral (cancrinite-type). A two-site ion-exchange model successfully simulated the Cs release from the LO-column. However, a three-site ion-exchange model was needed for the HI-column. The study implied that the weathering conditions greatly impact the speciation of the secondary minerals and leaching behavior of sequestrated Sr and Cs.

  5. Strontium and cesium release mechanisms during unsaturated flow through waste-weathered Hanford sediments.

    PubMed

    Chang, Hyun-Shik; Um, Wooyong; Rod, Kenton; Serne, R Jeff; Thompson, Aaron; Perdrial, Nicolas; Steefel, Carl I; Chorover, Jon

    2011-10-01

    Leaching behavior of Sr and Cs in the vadose zone of Hanford site (Washington) was studied with laboratory-weathered sediments mimicking realistic conditions beneath the leaking radioactive waste storage tanks. Unsaturated column leaching experiments were conducted using background Hanford pore water focused on first 200 pore volumes. The weathered sediments were prepared by 6 months reaction with a synthetic Hanford tank waste leachate containing Sr and Cs (10(-5) and 10(-3) molal representative of LO- and HI-sediment, respectively) as surrogates for (90)Sr and (137)Cs. The mineral composition of the weathered sediments showed that zeolite (chabazite-type) and feldspathoid (sodalite-type) were the major byproducts but different contents depending on the weathering conditions. Reactive transport modeling indicated that Cs leaching was controlled by ion-exchange, while Sr release was affected primarily by dissolution of the secondary minerals. The later release of K, Al, and Si from the HI-column indicated the additional dissolution of a more crystalline mineral (cancrinite-type). A two-site ion-exchange model successfully simulated the Cs release from the LO-column. However, a three-site ion-exchange model was needed for the HI-column. The study implied that the weathering conditions greatly impact the speciation of the secondary minerals and leaching behavior of sequestrated Sr and Cs. PMID:21859142

  6. Bioavailability of sediment-bound contaminants to marine organisms

    SciTech Connect

    Brown, B. |

    1993-09-01

    The bioavailability of sediment-bound contaminants to marine organisms indicates that there exists a potential for transfer of these contaminants through marine food webs to commercial fisheries products consumed by humans. However, there has been relatively little effort to combine and synthesize data on chemical/biological interactions between benthic animals and seagrasses and the sediments in which they reside on the one hand, and on the chemistry of bioaccumulation on the other. This report provides a conceptual basis for an approach to bioavailability and biomagnification of sediment-bound contaminants that reviews biological and chemical approaches.

  7. Uranium Contamination in the Subsurface Beneath the 300 Area, Hanford Site, Washington

    SciTech Connect

    Peterson, Robert E.; Rockhold, Mark L.; Serne, R. Jeffrey; Thorne, Paul D.; Williams, Mark D.

    2008-02-29

    This report provides a description of uranium contamination in the subsurface at the Hanford Site's 300 Area. The principal focus is a persistence plume in groundwater, which has not attenuated as predicted by earlier remedial investigations. Included in the report are chapters on current conditions, hydrogeologic framework, groundwater flow modeling, and geochemical considerations. The report is intended to describe what is known or inferred about the uranium contamination for the purpose of making remedial action decisions.

  8. Hydrocarbon Bioaccumulation from contaminated sediment by a deposit feeding polychaete

    SciTech Connect

    Weston, D.P. )

    1990-01-09

    This study examined the role of sediment organic carbon content in aromatic hydrocarbon bioaccumulation and assessed the importance of two routes of hydrocarbon uptake: (1) uptake of the dissolved contaminant fraction from interstitial or overlying water; and (2) uptake of the particulate contaminant fraction from ingested sediments. The lugworm, Abarenicola pacifica, was exposed to three sediments contaminated with [[sup 3]H] benzo(a)pyrene (BaP). By manipulating the organic content of these sediments it was possible to establish three treatments with similar BaP concentrations in the interstitial water, but differing in the amount of BaP in the bulk sediment. BaP bioaccumulation over the first few days of exposure was correlated with feeding rate, implicating ingested sediments as a source of implicating ingested sediments as a source of BaP. The greatest body burden, however, was attained in those individuals held in sediments with the lowest organic carbon content and the lowest BaP concentration. Body burden at steady state was not correlated with either BaP concentrations in bulk sediment (dry weight or organic normalized basis) or the interstitial water. Increased organic matter decreased BaP bioavailability in a non-linear fashion. Bioaccumulation factors relative to water and organic content were relatively constant between 1 and 2% organic carbon in the sediment, but these same accumulation factors substantially underestimated body burden if applied to sandy sediments with little (0.3%) organic carbon.

  9. Detecting and Quantifying Organic Contaminants in Sediments with NMR

    NASA Astrophysics Data System (ADS)

    Fay, E. L.; Knight, R. J.

    2015-12-01

    Nuclear magnetic resonance (NMR) methods have the potential to detect and monitor free-phase organic contaminants in sediments, both in the laboratory and in the field. NMR directly detects signal from hydrogen-bearing fluids; the signal amplitude is proportional to the total amount of hydrogen present, while the signal decay rate provides information about fluid properties and interactions with the surrounding sediments. Contrasting relaxation times (T2) or diffusion coefficients (D) allow the separation of water signal from contaminant signal. In this work, we conduct a laboratory study to assess the use of NMR measurements to detect and quantify diesel, gasoline, crude oil, and tri-chloroethylene in sediments. We compare the T2 distributions for sediments containing only water, only contaminant, and both water and contaminant, confirming that the identification and quantification of contaminants using T2 data alone is limited by overlapping water and contaminant T2 distributions in some sediments. We leverage the contrast between the diffusion coefficient of water and that of diesel and crude oil to separate contaminant signal from water signal in D-T2 maps. D-T2 distributions are measured both using a pulsed gradient method and a static gradient method similar to methods used with logging tools, allowing us to compare the ability of each method to quantify diesel and crude oil when water is also present. There is the potential to apply these methods to characterize and monitor contaminated sites using commercially available NMR logging tools.

  10. Contaminants in suspended sediment from the Fraser River basin

    SciTech Connect

    Sekela, M.; Baldazzi, C.; Moyle, G.; Brewer, R.

    1995-12-31

    The concentrations of trace organic contaminants were measured in suspended sediment samples collected upstream and downstream of six pulp mills located in the Fraser River basin. Sampling occurred at three hydrological periods; fall low flow, winter base flow (under ice) and spring freshet. Suspended sediments were analyzed for dioxins, furans, chlorinated phenolics and polycyclic aromatic hydrocarbons. Initial results indicate that (i) trace organic contaminants are detectable in suspended sediments collected over 265 river kilometers downstream of the nearest pulp mill; (ii) the 1992 to 1994 levels of 2,3,7,8-TCD-dioxin and 2,3,7,8-TCD-furan in Fraser river suspended sediments are lower than the levels measured in 1990; (iii) there is a measurable increase in trace organic contaminant levels in Fraser River suspended sediments associated with the initial rise in the Fraser River hydrograph at freshet.

  11. GEOELECTRICAL EVIDENCE OF MICROBIAL DEGRADATION OF DIESEL CONTAMINATED SEDIMENTS

    EPA Science Inventory

    The alteration of physical properties by microbial activity in petroleum contaminated sediments was investigated using geophysical techniques in laboratory column experiments. Microbial population growth was determined by the Most Probable Number technique (MPN), community dynami...

  12. Influence Of Groundwater Discharge On Arsenic Contamination In Sediments

    EPA Science Inventory

    A field investigation was conducted to evaluate the impact of a discharging arsenic plume on sediment contaminant characteristics at a site adjacent to a landfill in northeastern Massachusetts. Site characterization included assessment of the hydrologic and chemical samples coll...

  13. USING SPMDS TO ASSESS MANAGEMENT STRATEGIES FOR PCB CONTAMINATED SEDIMENTS.

    EPA Science Inventory

    Abstract: Dredging in-place treatment, capping and monitored natural recovery, used together or separately are the primary approaches for managing contaminated sediment risks. Understanding how well different approaches work in different environments is critical for choosing an...

  14. USING SPMDS TO ACCESS MANAGMENT STRATEGIES FOR PCB CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Dredging, in-place treatment, capping and monitored natural recovery, used together or separately are the primary approaches for managing contaminated sediment risks. Understanding how well different approaches work in different environments is critical for choosing an appropria...

  15. USING SPMDS TO ACCESS MANAGEMENT STRATEGIES FOR PCB CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Dredging, in-place treatment, capping and monitored natural recovery, used together or separately are the primary approaches for managing contaminated sediment risks. Understanding how well different approaches work in different environments is critical for choosing an appropria...

  16. Mechanistic sediment quality guidelines based on contaminant bioavailability: equilibrium partitioning sediment benchmarks.

    PubMed

    Burgess, Robert M; Berry, Walter J; Mount, David R; Di Toro, Dominic M

    2013-01-01

    Globally, estimated costs to manage (i.e., remediate and monitor) contaminated sediments are in the billions of U.S. dollars. Biologically based approaches for assessing the contaminated sediments which pose the greatest ecological risk range from toxicity testing to benthic community analysis. In addition, chemically based sediment quality guidelines (SQGs) provide a relatively inexpensive line of evidence for supporting these assessments. The present study summarizes a mechanistic SQG based on equilibrium partitioning (EqP), which uses the dissolved concentrations of contaminants in sediment interstitial waters as a surrogate for bioavailable contaminant concentrations. The EqP-based mechanistic SQGs are called equilibrium partitioning sediment benchmarks (ESBs). Sediment concentrations less than or equal to the ESB values are not expected to result in adverse effects and benthic organisms should be protected, while sediment concentrations above the ESB values may result in adverse effects to benthic organisms. In the present study, ESB values are reported for 34 polycyclic aromatic hydrocarbon, 32 other organic contaminants, and seven metals (cadmium, chromium, copper, nickel, lead, silver, zinc). Also included is an overview of EqP theory, ESB derivation, examples of applying ESB values, and considerations when using ESBs. The ESBs are intended as a complement to existing sediment-assessment tools, to assist in determining the extent of sediment contamination, to help identify chemicals causing toxicity, and to serve as targets for pollutant loading control measures.

  17. Borehole Calibration Facilities to Support Gamma Logging for Hanford Subsurface Investigation and Contaminant Monitoring - 13516

    SciTech Connect

    McCain, R.G.; Henwood, P.D.; Pope, A.D.; Pearson, A.W.

    2013-07-01

    Repeated gamma logging in cased holes represents a cost-effective means to monitor gamma-emitting contamination in the deep vadose zone over time. Careful calibration and standardization of gamma log results are required to track changes and to compare results over time from different detectors and logging systems. This paper provides a summary description of Hanford facilities currently available for calibration of logging equipment. Ideally, all logging organizations conducting borehole gamma measurements at the Hanford Site will take advantage of these facilities to produce standardized and comparable results. (authors)

  18. Fixation Mechanisms and Desorption Rates of Sorbed Cs in High-Level Waste Contaminated Subsurface Sediments: Implications to Future Behavior and In-Ground Stability

    SciTech Connect

    Zachara, John M.; McKinley, James P.; Ainsworth, Calvin C.; Serne, R. Jeff

    2001-06-01

    The high-yield fission product 137Cs is a major contaminant of the vadose zone at Hanford and other DOE sites. Over 100 kCi of 137Cs was discharged to the vadose zone in the S-SX tank farm at Hanford through the leakage of high-level waste from tanks SX-108 and SX-109. Although 137Cs is strongly sorbed by subsurface sediments, certain waste characteristics, such as high Na+, can expedite its migration and reduce its retardation to low values. This project is focused on defining the in-ground geochemistry of sorbed 137Cs released from high-level waste tanks, so that better future projections can be made of Cs mobility in the vadose zone. The project will study Cs-contaminated subsurface sediments from various Hanford tank farms to (1) determine the mineralogic and surface site residence of sorbed Cs in contaminated sediments varying in current Cs content and original waste composition, (2) establish geochemical factors and processes controlling Cs desorbability and desorption kinetics from contaminated sediment and Cs-enriched sediment particles, and (3) define and parameterize a kinetic model for Cs desorption that incorporates multi-site behavior and heterogeneous intraparticle Cs distribution.

  19. Separation, Characterization and Initial Reaction Studies of Magnetite Particles from Hanford Sediments

    SciTech Connect

    Baer, Donald R.; Grosz, Andrew E.; Ilton, Eugene S.; Krupka, Kenneth M.; Liu, Juan; Penn, Ryland L.; Pepin, Alex

    2010-04-24

    Magnetic and density separation methods have been applied to composite sediment sample from the Hanford formation from sediment recovered during drilling of an uncontaminated borehole located near the 200 West Area of the Hanford Site in southeastern Washington State. This paper describes the results of using those separation methods and from the characterization and initial reactivity measurements on a highly magnetic fraction isolated from that sediment. X-ray diffraction (XRD) analysis of the highly magnetic sediment fraction indicates that this material contains predominantly magnetite (Fe3O4). Particle morphology observed by scanning electron microscopy (SEM) and compositions determined energy dispersive spectroscopy (EDS) are consistent with this identification. Analyses by X-ray photoelectron spectroscopy (XPS) indicates that there is a thin coating on the particles that are likely a type of aluminosilicate. This highly magnetic fraction of material is not reactive with indigo carmine, an organic redox probe molecule that was shown to readily react with synthetic magnetite. Because of the limited amounts of material readily available, initial tests have been conducted that demonstrate the ability to complete U(VI) sorption on individual particles (nominally ~100 µm in size) of the isolated sediment and to remove and mount these individual particles for analysis of the concentration and chemical state of the sorbed U species using small area XPS.

  20. Resuspension of sediment, a new approach for remediation of contaminated sediment.

    PubMed

    Pourabadehei, Mehdi; Mulligan, Catherine N

    2016-06-01

    Natural events and anthropogenic activities are the reasons of undesirable resuspension of contaminated sediments in aquatic environment. Uncontrolled resuspension could remobilize weakly bound heavy metals into overlying water and pose a potential risk to aquatic ecosystem. Shallow harbours, with contaminated sediments are subjected to the risk of uncontrolled resuspension. Remediation of sediments in these areas cannot be performed by conventional in situ methods (e.g. capping with or without reactive amendment). Ex situ remediation also requires dredging of sediment, which could increase the risk of spreading contaminants. Alternatively, the resuspension technique was introduced to address these issues. The concept of the resuspension method is that finer sediments have a greater tendency to adsorb the contamination. Therefore, finer sediments, believed carry more concentration of contaminants, were targeted for removal from aquatic environment by a suspension mechanism in a confined water column. The objective of this study was to evaluate the feasibility of the resuspension technique as a new approach for remediation of contaminated sediment and a viable option to reduce the risk of remobilization of contaminants in harbours due to an undesirable resuspension event. Unlike the common in situ techniques, the resuspension method could successfully reduce the total concentration of contaminants in almost all samples below the probable effect level (PEL) with no significant change in the quality of overlying water. The results indicated that removal efficiency could be drastically enhanced for metals in sediment with a higher enrichment factor. Moreover, availability of metals (e.g. Cd and Pb) with a high concentration in labile fractions was higher in finer sediments with a high enrichment factor. Consequently, removal of contaminants from sediment through the resuspension method could reduce the risk of mobility and availability of metals under changing

  1. Toxicity of lead-contaminated sediment to mute swans

    USGS Publications Warehouse

    Day, D.D.; Beyer, W.N.; Hoffman, D.J.; Morton, Alexandra; Sileo, L.; Audet, D.J.; Ottinger, M.A.

    2003-01-01

    Most ecotoxicological risk assessments of wildlife emphasize contaminant exposure through ingestion of food and water. However, the role of incidental ingestion of sediment-bound contaminants has not been adequately appreciated in these assessments. This study evaluates the toxicological consequences of contamination of sediments with metals from hard-rock mining and smelting activities. Lead-contaminated sediments collected from the Coeur d'Alene River Basin in Idaho were combined with either a commercial avian maintenance diet or ground rice and fed to captive mute swans (Cygnus olor) for 6 weeks. Experimental treatments consisted of maintenance or rice diets containing 0, 12 (no rice group), or 24% highly contaminated (3,950 ug/g lead) sediment or 24% reference (9.7 ug/g lead) sediment. Although none of the swans died, the group fed a rice diet containing 24% lead-contaminated sediment were the most severely affected, experiencing a 24% decrease in mean body weight, including three birds that became emaciated. All birds in this treatment group had nephrosis; abnormally dark, viscous bile; and significant (p < 0.05) reductions in hematocrit and hemoglobin concentrations compared to their pretreatment levels. This group also had the greatest mean concentrations of lead in blood (3.2 ug/g), brain (2.2 ug/g), and liver (8.5 ug/g). These birds had significant (alpha = 0.05) increases in mean plasma alanine aminotransferase activity, cholesterol, and uric acid concentrations and decreased plasma triglyceride concentrations compared to all other treatment groups. After 14 days of exposure, mean protoporphyrin concentrations increased substantially, and mean delta-aminolevulinic acid dehydratase activity decreased by more than 95% in all groups fed diets containing highly contaminated sediments. All swans fed diets that contained 24% lead-contaminated sediment had renal acid-fast intranuclear inclusion bodies, which are diagnostic of lead poisoning in waterfowl. Body

  2. Evaluation of sediment contamination in Pearl Harbor. Final report

    SciTech Connect

    Grovhoug, J.G.

    1992-06-01

    Pearl Harbor demonstrates remarkable resilience to natural and human-induced contaminant stresses. A review of more than fifty harbor-specific data sets reveals a complex contamination and recovery history. Siltation is a major contaminant pathway in Pearl Harbor. Dredging operations, which are necessary due to high siltation rates, reduce contaminant loading by periodically removing the upper harbor sediment layers. The response of test organisms during sediment toxicity and bioaccumulation studies showed negligible effects from sediment toxicity. The environmental quality at an offshore dredge disposal site for the harbor is not measurable affected. Urban runoff via storm drains and tributaries is an important nonpoint source of contaminant exposure to the Pearl Harbor ecosystem. Most contaminants experience extensive physical, chemical, and biological, modification after entering the harbor environment. Certain contaminants, including PCBs, petroleum hydrocarbons, and silver, were reported at sufficiently elevated sediment concentrations to warrant environmental concern in some harbor regions and may warrant further evaluation. The overall sediment quality in Pearl Harbor, however, is less degraded than that of many U.S. mainland coastal harbors. Further detailed study of the abundance and distribution of important marine resources in Pearl Harbor is recommended.

  3. Passive sampling methods for contaminated sediments: risk assessment and management.

    PubMed

    Greenberg, Marc S; Chapman, Peter M; Allan, Ian J; Anderson, Kim A; Apitz, Sabine E; Beegan, Chris; Bridges, Todd S; Brown, Steve S; Cargill, John G; McCulloch, Megan C; Menzie, Charles A; Shine, James P; Parkerton, Thomas F

    2014-04-01

    This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree ), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal ) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree ) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. PMID

  4. Passive sampling methods for contaminated sediments: Risk assessment and management

    PubMed Central

    Greenberg, Marc S; Chapman, Peter M; Allan, Ian J; Anderson, Kim A; Apitz, Sabine E; Beegan, Chris; Bridges, Todd S; Brown, Steve S; Cargill, John G; McCulloch, Megan C; Menzie, Charles A; Shine, James P; Parkerton, Thomas F

    2014-01-01

    This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. Integr

  5. Passive sampling methods for contaminated sediments: risk assessment and management.

    PubMed

    Greenberg, Marc S; Chapman, Peter M; Allan, Ian J; Anderson, Kim A; Apitz, Sabine E; Beegan, Chris; Bridges, Todd S; Brown, Steve S; Cargill, John G; McCulloch, Megan C; Menzie, Charles A; Shine, James P; Parkerton, Thomas F

    2014-04-01

    This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree ), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal ) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree ) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed.

  6. Ocean acidification increases the toxicity of contaminated sediments.

    PubMed

    Roberts, David A; Birchenough, Silvana N R; Lewis, Ceri; Sanders, Matthew B; Bolam, Thi; Sheahan, Dave

    2013-02-01

    Ocean acidification (OA) may alter the behaviour of sediment-bound metals, modifying their bioavailability and thus toxicity. We provide the first experimental test of this hypothesis with the amphipod Corophium volutator. Amphipods were exposed to two test sediments, one with relatively high metals concentrations (Σmetals 239 mg kg(-1) ) and a reference sediment with lower contamination (Σmetals 82 mg kg(-1) ) under conditions that mimic current and projected conditions of OA (390-1140 μatm pCO2 ). Survival and DNA damage was measured in the amphipods, whereas the flux of labile metals was measured in the sediment and water column (WC) using Diffusive Gradients in Thin-films. The contaminated sediments became more acutely toxic to C. volutator under elevated pCO2 (1140 μatm). There was also a 2.7-fold increase in DNA damage in amphipods exposed to the contaminated sediment at 750 μatm pCO2 , as well as increased DNA damage in organisms exposed to the reference sediment, but only at 1140 μatm pCO2 . The projected pCO2 concentrations increased the flux of nickel and zinc to labile states in the WC and pore water. However, the increase in metal flux at elevated pCO2 was equal between the reference and contaminated sediments or, occasionally, greater from reference sediments. Hence, the toxicological interaction between OA and contaminants could not be explained by e ffects of pH on metal speciation. We propose that the additive physiological effects of OA and contaminants will be more important than changes in metal speciation in determining the responses of benthos to contaminated sediments under OA. Our data demonstrate clear potential for near-future OA to increase the susceptibility of benthic ecosystems to contaminants. Environmental policy should consider contaminants within the context of changing environmental conditions. Specifically, sediment metals guidelines may need to be reevaluated to afford appropriate environmental protection under future

  7. Contaminated sediment removal from a spent fuel storage canal

    SciTech Connect

    Geber, K R

    1993-01-01

    A leaking underground spent fuel transfer canal between a decommissioned reactor and a radiochemical separations building at the Oak Ridge National Laboratory (ORNL) was found to contain RCRA-hazardous and radioactive sediment. Closure of the Part B RCRA permitted facility required the use of an underwater robotic vacuum and a filtration-containment system to separate and stabilize the contaminated sediment. This paper discusses the radiological controls established to maintain contamination and exposures As Low As Reasonably Achievable (ALARA) during the sediment removal.

  8. Contaminated marine sediments: Water column and interstitial toxic effects

    SciTech Connect

    Burgess, R.M.; Schweitzer, K.A.; McKinney, R.A.; Phelps, D.K.

    1993-01-01

    The toxicity that contaminated sediments may introduce into the water column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated marine sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentrations of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. Water column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial water toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in water column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial waters did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.

  9. Contaminated marine sediments: Water column and interstitial toxic effects

    SciTech Connect

    Burgess, R.M.; McKinney, R.A. ); Schweitzer, K.A. ); Phelps, D.K. )

    1993-01-01

    The toxicity that contaminated sediments may introduce into the water column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated marine sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentration of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. Water column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial water toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in water column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial water did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.

  10. Radioiodine sorption/desorption and speciation transformation by subsurface sediments from the Hanford Site.

    PubMed

    Xu, Chen; Kaplan, Daniel I; Zhang, Saijin; Athon, Matthew; Ho, Yi-Fang; Li, Hsiu-Ping; Yeager, Chris M; Schwehr, Kathleen A; Grandbois, Russell; Wellman, Dawn; Santschi, Peter H

    2015-01-01

    During the last few decades, considerable research efforts have been extended to identify more effective remediation treatment technologies to lower the (129)I concentrations to below federal drinking water standards at the Hanford Site (Richland, USA). Few studies have taken iodate into consideration, though recently iodate, instead of iodide, was identified as the major species in the groundwater of 200-West Area within the Hanford Site. The objective of this study was thus to quantify and understand aqueous radioiodine species transformations and uptake by three sediments collected from the semi-arid, carbonate-rich environment of the Hanford subsurface. All three sediments reduced iodate (IO3(-)) to iodide (I(-)), but the loamy-sand sediment reduced more IO3(-) (100% reduced within 7 days) than the two sand-textured sediments (∼20% reduced after 28 days). No dissolved organo-iodine species were observed in any of these studies. Iodate uptake Kd values ([Isolid]/[Iaq]; 0.8-7.6 L/kg) were consistently and appreciably greater than iodide Kd values (0-5.6 L/kg). Furthermore, desorption Kd values (11.9-29.8 L/kg) for both iodate and iodide were consistently and appreciably greater than uptake Kd values (0-7.6 L/kg). Major fractions of iodine associated with the sediments were unexpectedly strongly bound, such that only 0.4-6.6 % of the total sedimentary iodine could be exchanged from the surface with KCl solution, and 0-1.2% was associated with Fe or Mn oxides (weak NH2HCl/HNO3 extractable fraction). Iodine incorporated into calcite accounted for 2.9-39.4% of the total sedimentary iodine, whereas organic carbon (OC) is likely responsible for the residual iodine (57.1-90.6%) in sediments. The OC, even at low concentrations, appeared to be controlling iodine binding to the sediments, as it was found that the greater the OC concentrations in the sediments, the greater the values of uptake Kd, desorption Kd, and the greater residual iodine concentrations (non

  11. Sediments Contamination with Organic Micropollutants: Current State and Perspectives

    NASA Astrophysics Data System (ADS)

    Popenda, Agnieszka; Włodarczyk-Makuła, Maria

    2016-06-01

    This study focused on the sediment contamination with some organic micropollutants based on the monitoring data together with available literature in Poland. The following persistent organic pollutants (POPs): polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides (CP) were characterized in sediments with respect to current legislations in force. Based on accessible data, higher PAHs, PCBs and CP concentrations were found in river sediments than in lake sediments. Especially, sediments of the Oder River and its tributary in the southern part of Poland, were highly polluted. In order to minimize the risk of the secondary pollution of surface waters, it is necessary to introduce consolidated management system with sediments proceeding. Furthermore, it is also of great importance to elaborate specific regulations concerning conditions of sediments management.

  12. Microbial interactions with naturally occurring hydrophobic sediments: Influence on sediment and associated contaminant mobility.

    PubMed

    Droppo, I G; Krishnappan, B G; Lawrence, J R

    2016-04-01

    The erosion, transport and fate of sediments and associated contaminants are known to be influenced by both particle characteristics and the flow dynamics imparted onto the sediment. The influential role of bitumen containing hydrophobic sediments and the microbial community on sediment dynamics are however less understood. This study links an experimental evaluation of sediment erosion with measured sediment-associated contaminant concentrations and microbial community analysis to provide an estimate of the potential for sediment to control the erosion, transport and fate of contaminants. Specifically the paper addresses the unique behaviour of hydrophobic sediments and the role that the microbial community associated with hydrophobic sediment may play in the transport of contaminated sediment. Results demonstrate that the hydrophobic cohesive sediment demonstrates unique transport and particle characteristics (poor settling and small floc size). Biofilms were observed to increase with consolidation/biostabilization times and generated a unique microbial consortium relative to the eroded flocs. Natural oil associated with the flocs appeared to be preferentially associated with microbial derived extracellular polymeric substances. While PAHs and naphthenic acid increased with increasing shear (indicative of increasing loads), they tended to decrease with consolidation/biostabilization (CB) time at similar shears suggesting a chemical and/or biological degradation. PAH and napthenic acid degrading microbes decreased with time as well, which may suggest that there was a reduced pool of PAHs and naphthenic acids available resulting in their die off. This study emphasizes the importance that any management strategies and operational assessments for the protection of human and aquatic health incorporate the sediment (suspended and bed sediment) and biological (biofilm) compartments and the energy dynamics within the system in order to better predict contaminant

  13. Contaminant Release Data Package for Residual Waste in Single-Shell Hanford Tanks

    SciTech Connect

    Deutsch, William J.; Cantrell, Kirk J.; Krupka, Kenneth M.

    2007-12-01

    The Hanford Federal Facility Agreement and Consent Order requires that a Resource Conservation and Recovery Act (RCRA) Facility Investigation report be submitted to the Washington State Department of Ecology. The RCRA Facility Investigation report will provide a detailed description of the state of knowledge needed for tank farm performance assessments. This data package provides detailed technical information about contaminant release from closed single-shell tanks necessary to support the RCRA Facility Investigation report. It was prepared by Pacific Northwest National Laboratory (PNNL) for CH2M HILL Hanford Group, Inc., which is tasked by the U.S. Department of Energy (DOE) with tank closure. This data package is a compilation of contaminant release rate data for residual waste in the four Hanford single-shell tanks (SSTs) that have been tested (C-103, C-106, C-202, and C-203). The report describes the geochemical properties of the primary contaminants of interest from the perspective of long-term risk to groundwater (uranium, technetium-99, iodine-129, chromium, transuranics, and nitrate), the occurrence of these contaminants in the residual waste, release mechanisms from the solid waste to water infiltrating the tanks in the future, and the laboratory tests conducted to measure release rates.

  14. Vitrification testing of soil fines from contaminated Hanford 100 Area and 300 Area soils

    SciTech Connect

    Ludowise, J.D.

    1994-05-01

    The suitability of Hanford soil for vitrification is well known and has been demonstrated extensively in other work. The tests reported here were carried out to confirm the applicability of vitrification to the soil fines (a subset of the Hanford soil potentially different in composition from the bulk soil) and to provide data on the performance of actual, vitrified soil fines. It was determined that the soil fines were generally similar in composition to the bulk Hanford soil, although the fraction <0.25 mm in the 100 Area soil sample appears to differ somewhat from the bulk soil composition. The soil fines are readily melted into a homogeneous glass with the simple additions of CaO and/or Na{sub 2}O. The vitrified waste (plus additives) occupies only 60% of the volume of the initial untreated waste. Leach testing has shown the glasses made from the soil fines to be very durable relative to natural and man-made glasses and has demonstrated the ability of the vitrified waste to greatly reduce the release of radionuclides to the environment. Viscosity and electrical conductivity measurements indicate that the soil fines will be readily processable, although with levels of additives slightly greater than used in the radioactive melts. These tests demonstrate the applicability of vitrification to the contaminated soil fines and the exceptional performance of the waste form resulting from the vitrification of contaminated Hanford soils.

  15. Comparison of Field Groundwater Biostimulation Experiments Using Polylactate and Lactate Solutions at the Chromium-Contaminated Hanford 100-H Site

    NASA Astrophysics Data System (ADS)

    Hazen, T. C.; Faybishenko, B.; Beller, H. R.; Brodie, E. L.; Sonnenthal, E. L.; Steefel, C.; Larsen, J.; Conrad, M. E.; Bill, M.; Christensen, J. N.; Brown, S. T.; Joyner, D.; Borglin, S. E.; Geller, J. T.; Chakraborty, R.; Nico, P. S.; Long, P. E.; Newcomer, D. R.; Arntzen, E.

    2011-12-01

    The primary contaminant of concern in groundwater at the DOE Hanford 100 Area (Washington State) is hexavalent chromium [Cr(VI)] in Hanford coarse-grained sediments. Three lactate injections were conducted in March, August, and October 2010 at the Hanford 100-H field site to assess the efficacy of in situ Cr(VI) bioreductive immobilization. Each time, 55 gal of lactate solution was injected into the Hanford aquifer. To characterize the biogeochemical regimes before and after electron donor injection, we implemented a comprehensive plan of groundwater sampling for microbial, geochemical, and isotopic analyses. These tests were performed to provide evidence of transformation of toxic and soluble Cr(VI) into less toxic and poorly soluble Cr(III) by bioimmobilization, and to quantify critical and interrelated microbial metabolic and geochemical mechanisms affecting chromium in situ reductive immobilization and the long-term sustainability of chromium bioremediation. The results of lactate injections were compared with data from two groundwater biostimulation tests that were conducted in 2004 and 2008 by injecting Hydrogen Release Compound (HRC°), a slow-release glycerol polylactate, into the Hanford aquifer. In all HRC and lactate injection tests, 13C-labeled lactate was added to the injected solutions to track post-injection carbon pathways. Monitoring showed that despite a very low initial total microbial density (from <104 to 105 cells/mL), both HRC and lactate injections stimulated anaerobic microbial activity, which led to an increase in biomass to >107 cells/mL (including sulfate- and nitrate-reducing bacteria), resulting in a significant decrease in soluble Cr(VI) concentrations to below the MCL. In all tests, lactate was consumed nearly completely within the first week, much faster than HRC. Modeling of biogeochemical and isotope fractionation processes with the reaction-transport code TOUGHREACT captured the biodegradation of lactate, fermentative production

  16. Mercury contaminated sediment sites—An evaluation of remedial options

    SciTech Connect

    Randall, Paul M.; Chattopadhyay, Sandip

    2013-08-15

    Mercury (Hg) is a naturally-occurring element that is ubiquitous in the aquatic environment. Though efforts have been made in recent years to decrease Hg emissions, historically-emitted Hg can be retained in the sediments of aquatic bodies where they may be slowly converted to methylmercury (MeHg). Consequently, Hg in historically-contaminated sediments can result in high levels of significant exposure for aquatic species, wildlife and human populations consuming fish. Even if source control of contaminated wastewater is achievable, it may take a very long time, perhaps decades, for Hg-contaminated aquatic systems to reach relatively safe Hg levels in both water and surface sediment naturally. It may take even longer if Hg is present at higher concentration levels in deep sediment. Hg contaminated sediment results from previous releases or ongoing contributions from sources that are difficult to identify. Due to human activities or physical, chemical, or biological processes (e.g. hydrodynamic flows, bioturbation, molecular diffusion, and chemical transformation), the buried Hg can be remobilized into the overlying water. Hg speciation in the water column and sediments critically affect the reactivity (i.e. conversion of inorganic Hg(II) to MeHg), transport, and its exposure to living organisms. Also, geochemical conditions affect the activity of methylating bacteria and its availability for methylation. This review paper discusses remedial considerations (e.g. key chemical factors in fate and transport of Hg, source characterization and control, environmental management procedures, remediation options, modeling tools) and includes practical case studies for cleaning up Hg-contaminated sediment sites. -- Highlights: ► Managing mercury-contaminated sediment sites are challenging to remediate. ► Remediation technologies are making a difference in managing these sites. ► Partitioning plays a dominant role in the distribution of mercury species. ► Mathematical

  17. HYDROLASING OF CONTAMINATED UNDERWATER BASIN SURFACES AT THE HANFORD K-AREA

    SciTech Connect

    CHRONISTER, G.B.

    2005-06-14

    This paper discusses selecting and Implementing hydrolasing technology to reduce radioactive contamination in preparing to dispose of the K Basins; two highly contaminated concrete basins at the Hanford Site. A large collection of spent nuclear fuel stored for many years underwater at the K Basins has been removed to stable, dry, safe storage. Remediation activities have begun for the remaining highly contaminated water, sludge, and concrete basin structures. Hydrolasing will be used to decontaminate and prepare the basin structures for disposal. The U. S. Department of Energy's (DOE) Hanford Site is considered the world's largest environmental cleanup project. The site covers 1,517 Km{sup 2} (586 square miles) along the Columbia River in an arid region of the northwest United States (U.S.). Hanford is the largest of the US former nuclear defense production sites. From the World War II era of the mid-1940s until the late-1980s when production stopped, Hanford produced 60 percent of the plutonium for nuclear defense and, as a consequence, produced a significant amount of environmental pollution now being addressed. Spent nuclear fuel was among the major challenges for DOE's environmental cleanup mission at Hanford. The end of production left Hanford with about 105,000 irradiated, solid uranium metal fuel assemblies--representing approximately 2,100 metric tons (80 percent of DOE's spent nuclear fuel). The fuel was ultimately stored in the K Basins water-filled, concrete basins attached to Hanford's K East (KE) and K West (KW) reactors. K Basin's fuel accounted for 95 percent of the total radioactivity in Hanford's former reactor production areas. Located about 457 meters (500 yards) from the Columbia River, the K Basins are two indoor, rectangular structures of reinforced concrete; each filled with more than 3.8 million liters (one million gallons) of water that has become highly contaminated with long-lived radionuclides. At the KW Basin, fuel was packaged and

  18. Solid waste leach characteristics and contaminant-sediment interactions Volume 2: Contaminant transport under unsaturated moisture contents

    SciTech Connect

    Lindenmeier, C.W.; Serne, R.J.; Conca, J.L.

    1995-09-01

    The objectives of this report and subsequent volumes include describing progress on (1) development and optimization of experimental methods to quantify the release of contaminants from solid wastes and their subsequent interactions with unsaturated sediments and (2) the creation of empirical data that become input parameters to performance assessment (PA) analyses for future Hanford Site disposal units and baseline risk assessments for inactive and existing solid waste disposal units. For this report, efforts focused on developing methodologies to evaluate contaminant transport in Trench 8 (W-5 Burial Ground) sediments under unsaturated (vadose zone) conditions. To accomplish this task, a series of flow-through column tests were run using standard saturated column systems, Wierenga unsaturated column systems (both commercial and modified), and the Unsaturated Flow Apparatus (UFA). The reactants investigated were {sup 85}Sr, {sup 236}U, and {sup 238}U as reactive tracers, and tritium as a non-reactive tracer. Results indicate that for moderately unsaturated conditions (volumetric water contents >50 % of saturation), the Wierenga system performed reasonably well such that long water residence times (50-147 h) were achieved, and reasonably good steady-state flow conditions were maintained. The major drawbacks in using this system for reactive tracer work included (1) the inability to achieve reproducible and constant moisture content below 50% of saturation, (2) the four to six month time required to complete a single test, and (3) the propensity for mechanical failure resulting from laboratory power outages during the prolonged testing period.

  19. MinChem: A Prototype Petrologic Database for Hanford Site Sediments

    SciTech Connect

    Mackley, Rob D.; Last, George V.; Serkowski, John A.; Middleton, Lisa A.; Cantrell, Kirk J.

    2010-09-01

    A prototype petrologic database (MinChem) has been under continual development for several years. MinChem contains petrologic, mineralogical, and bulk-rock geochemical data for Hanford Site sediments collected over multiple decades. The database is in relational form and consists of a series of related tables modeled after the Hanford Environmental Information System HEIS (BHI 2002) structures. The HEIS-compatible tables were created in anticipation of eventual migration into HEIS, or some future form of HEIS (e.g. HEIS-GEO). There are currently a total of 13,129 results in MinChem from 521 samples collected at 381 different sampling sites. These data come from 19 different original source documents published and unpublished (e.g. letter reports) between 1976 and 2009. The data in MinChem consist of results from analytical methods such as optical and electron microscopy, x-ray diffraction, x-ray fluorescence, and electron probe microanalysis.

  20. Dispersion of plutonium from contaminated pond sediments

    USGS Publications Warehouse

    Rees, T.F.; Cleveland, J.M.; Carl, Gottschall W.

    1978-01-01

    Sediment-water distributions of plutonium as a function of pH and contact time are investigated in a holding pond at the Rocky Flats plant of the Department of Energy. Although plutonium has been shown to sorb from natural waters onto sediments, the results of this study indicate that under the proper conditions it can be redispersed at pH 9 and above. Concentrations greater than 900 pCi Pu/L result after 34 h contact at pH 11 or 12 and the distribution coefficient, defined as the ratio of concentration in the sediment to that in the liquid, decreases from 1.1 ?? 105 at pH 7 to 1.2 ?? 103 at pH 11. The plutonium is probably dispersed as discrete colloids or as hydrolytic species adsorbed onto colloidal sediment particles whose average size decreases with increasing pH above pH 9. About 5% of the total plutonium is dispersed at pH 12, and the dispersion seems to readsorb on the sediment with time. Consequently, migration of plutonium from the pond should be slow, and it would be difficult to remove this element completely from pond sediment by leaching with high pH solutions. ?? 1978 American Chemical Society.

  1. Hanford Tank 241-C-106: Residual Waste Contaminant Release Model and Supporting Data

    SciTech Connect

    Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

    2005-06-03

    CH2M HILL is producing risk/performance assessments to support the closure of single-shell tanks at the DOE's Hanford Site. As part of this effort, staff at PNNL were asked to develop release models for contaminants of concern that are present in residual sludge remaining in tank 241-C-106 (C-106) after final retrieval of waste from the tank. This report provides the information developed by PNNL.

  2. Ecological risk assessment for river sediments contaminated by creosote

    SciTech Connect

    Pastorok, R.A.; Sampson, J.R.; Jacobson, M.A. ); Peek, D.C. )

    1994-12-01

    An ecological risk assessment was conducted for sediments of the lower Willamette River near a wood-treatment (creosote) facility. Both surface ad subsurface sediments near the facility are contaminated by polycyclic aromatic hydrocarbons (PAHs). Limited contamination of sediments by dioxins/furans, chlorinated phenols, and arsenic was also observed. Sediment bioassays based on amphipod (Hyalella azteca) mortality and Microtox[reg sign] (Photobacterium phosphoreum) bioluminescence showed toxicity within approximately 300 ft of the shoreline, with a highly toxic area (i.e., possible acute lethal effects in sedentary benthic species) near a dock used for creosote off-loading. The relatively low concentrations of contaminants measured in crayfish muscle tissue and the absence of serious lesions in livers of large-scale sucker collected near the site suggest that excess risk to mobile species from chronic contamination is low. Cursory observations indicate that acute toxic effects on crayfish may be associated with creosote seeps. There is no evidence of adverse biological effects throughout most of the main channel of the river. Evaluation of sediment chemistry data for PAHs relative to available sediment-quality criteria proposed by the US Environmental Protection Agency supports this conclusion.

  3. Mineral-Water Interface Processes Affecting Uranium Fate in Contaminated Sediments

    NASA Astrophysics Data System (ADS)

    Catalano, J. G.

    2011-12-01

    Widespread uranium contamination of soil, sediments, and groundwater systems has resulted from mining activities, nuclear weapon production, and energy generation. The fate and transport of uranium in such systems is strongly affected by geochemical processes occurring at mineral-water interfaces. I will present a summary of the mineral-water interface processes found to affect uranium fate in example contaminated sediments at the U.S. Department of Energy's Hanford sites and in related model systems. Processes occurring under oxic conditions will be the primary focus of this talk as under these conditions uranium is most mobile and thus presents the greatest hazard. Three dominant solid-phase uranium species are observed in contaminated soil and sediments at the Hanford site: uranyl silicates, uranyl phosphates, and uranyl adsorbed to clays and iron oxides. In deep sediments, uranyl silicates are found in microfractures in feldspar grains, likely because slow diffusion in such fractures maintains a high silicate activity. Such silicates are also found in waste-impacted shallow sediments and soil; waste fluids or evaporative processes may have generated the silicate activity needed to produce such phases. Uranyl phosphates are less abundant, occurring primarily in shallow sediments exposed to P-bearing waste fluids. However, remediation approaches under consideration may produce substantial quantities of uranyl phosphates in the future. Adsorbed uranyl is dispersed throughout contaminated soils and shallow sediments and likely has the greatest potential for remobilization. Analogue studies show that precipitation of uranyl phosphates is rapid when such phases are supersaturated and that both homogeneous and heterogeneous nucleation may occur. Specific adsorption of uranyl to minerals is strongly affected by the presence of complexation anions. Carbonate suppresses uranyl adsorption but also forms uranyl-carbonate ternary surface complexes. At conditions below

  4. IN SITU REMEDIATION OF CONTAMINATED SEDIMENTS - ACTIVE CAPPING TECHNOLOGY

    SciTech Connect

    Knox, A.; Roberts, J.; Paller, M.; Reible, D.

    2010-09-02

    Active capping is a relatively new approach for treating contaminated sediments. It involves applying chemically reactive amendments to the sediment surface. The main role of active caps is to stabilize contaminants in contaminated sediments, lower the bioavailable pool of contaminants, and reduce the release of contaminants to the water column. Metals are common contaminants in many marine and fresh water environments as a result of industrial and military activities. The mobile, soluble forms of metals are generally considered toxic. Induced chemical precipitation of these metals can shift toxic metals from the aqueous phase to a solid, precipitated phase which is often less bioavailable. This approach can be achieved through application of sequestering agents such as rock phosphates, organoclays, zeolites, clay minerals, and biopolymers (e.g., chitosan) in active capping technology. Active capping holds great potential for a more permanent solution that avoids residual risks resulting from contaminant migration through the cap or breaching of the cap. In addition to identifying superior active capping agents, research is needed to optimize application techniques, application rates, and amendment combinations that maximize sequestration of contaminants. A selected set of active capping treatment technologies has been demonstrated at a few sites, including a field demonstration at the Savannah River Site, Aiken, SC. This demonstration has provided useful information on the effects of sequestering agents on metal immobilization, bioavailability, toxicity, and resistance to mechanical disturbance.

  5. Accumulation by fish of contaminants released from dredged sediments

    USGS Publications Warehouse

    Seelye, James G.; Hesselberg, Robert J.; Mac, Michael J.

    1982-01-01

    Inasmuch as the process of dredging and disposing of dredged materials causes a resuspension of these materials and an increase in bioavailability of associated contaminants, we conducted a series of experiments to examine the potential accumulation by fish of contaminants from suspended sediments. In the first experiment we compared accumulation of contaminants by yellow perch of hatchery and lake origin and found that after 10 days of exposure to nonaerated sediments, fish of hatchery origin accumulated PCBs and Fe, while fish of lake origin accumulated As, Cr, Fe, and Na. Two additional exposures were conducted to evaluate the effects of aerating the sediments prior to measuring bioavailability of associated contaminants. Fish of hatchery origin exposed to nonaerated sediments for 10 days accumulated PCBs and Hg, while fish of hatchery origin exposed to aerated sediments for 10 days accumulated PCBs, DDE, Zn, Fe, Cs, and Se. These results demonstrated not only the potential for uptake of contaminants by fish as a result of dredging but also the potential utility of fish bioassays in evaluating proposed dredging operations.

  6. Options To Cleanup Site-wide Vadose Zone Contamination At The Hanford Site, WA, State

    SciTech Connect

    Goswami, D.

    2008-07-01

    The U.S. Department of Energy (DOE) Hanford Site in south central Washington State lies along the Columbia River and is one of DOE's largest legacy waste management sites. Enormous radionuclide and chemical inventories exist below-ground. These include Resource Conservation and Recovery Act (RCRA) storage facilities where hazardous and radioactive contaminants were discharged and leaked to the soil surface and to the deep vadose zone and groundwater. The vadose zone is also contaminated from facilities regulated by the RCRA and Comprehensive Environmental Response Compensation and Liability Act (CERCLA) Act. Hanford now contains as much as 28,300 cubic meters of soil contaminated with radionuclides from liquid wastes released near processing facilities. The Hanford Federal Facility Agreement and Consent Order, Tri-Party Agreement (TPA) has set the completion of the cleanup of these sites by 2024. There are numerous technical and regulatory challenges to cleanup of the vadose zone at the Hanford site. This paper attempts to identify the categories of deep vadose zone problem and identifies a few possible regulatory options to clean up the site under the mix of state and federal regulatory authorities. There are four major categories of vadose contamination areas at the Hanford Site. The first is laterally extensive with intermediate depth (ground surface to about 45 meters depth) mostly related to high volume effluent discharge into cribs, ponds and ditches of designated CERCLA facilities. The second is dominated by laterally less extensive mostly related to leaks from RCRA tank farms. The later contamination is often commingled at depth with wastes from adjacent CERCLA facilities. The third category is from the high volume CERCLA facilities extending from the surface to more than 60 meters below ground. Contamination from the later category crosses the entire thickness of the vadose zone and reached groundwater. The fourth category is the lower volume waste sites

  7. Mechanistic Sediment Quality Guidelines Based on Contaminant Bioavailability: Equilibrium Partitioning Sediment Benchmarks

    EPA Science Inventory

    Globally, billions of metric tons of contaminated sediments are present in aquatic systems representing a potentially significant ecological risk. Estimated costs to manage (i.e., remediate and monitor) these sediments are in the billions of U.S. dollars. Biologically-based app...

  8. Mapping and monitoring contaminated-sediment geometry and stability.

    PubMed

    Rukavina, N

    2001-02-01

    Environment Canada's National Water Research Institute (NWRI) conducts research on freshwater contaminated sediments, much of which is focused on designated areas of concern in the Great Lakes and their connecting channels. This paper reviews new acoustic and video equipment and procedures developed to map the geometry and stability of the sediments, and describes their applications. A RoxAnn acoustic seabed-classification system is used for mapping bottom-sediment types and locating the deposits of fine-grained sediments with which contaminants are associated. The system uses the acoustic properties of sediments to distinguish textural types ranging from mud to boulders, and displays the data as they are collected. The sediment thickness is measured with a weighted video-acoustic tripod which is lowered into the sediments to refusal, and which recorded penetration with a video camera or an echosounder transducer. The stability of the contaminated sediments was monitored with a bottom-mounted, high-precision echo sounder-digitizer, which logs changes in the position of the sediment-water interface produced by erosion or deposition. The same procedure can be used in capping or dredging projects to track bottom changes as they occur, or they can be measured by pre- and post-project mapping of bathymetry and morphology with sweep-sonar or side-scan sonar equipment. The new equipment and procedures have been successfully applied to a number of areas of concern in the Great Lakes basin. They provide a faster and more detailed characterization of sediment properties and geometry than was previously available, and have been particularly effective in optimizing sampling surveys and monitoring remediation projects. PMID:11258831

  9. Mapping and monitoring contaminated-sediment geometry and stability.

    PubMed

    Rukavina, N

    2001-02-01

    Environment Canada's National Water Research Institute (NWRI) conducts research on freshwater contaminated sediments, much of which is focused on designated areas of concern in the Great Lakes and their connecting channels. This paper reviews new acoustic and video equipment and procedures developed to map the geometry and stability of the sediments, and describes their applications. A RoxAnn acoustic seabed-classification system is used for mapping bottom-sediment types and locating the deposits of fine-grained sediments with which contaminants are associated. The system uses the acoustic properties of sediments to distinguish textural types ranging from mud to boulders, and displays the data as they are collected. The sediment thickness is measured with a weighted video-acoustic tripod which is lowered into the sediments to refusal, and which recorded penetration with a video camera or an echosounder transducer. The stability of the contaminated sediments was monitored with a bottom-mounted, high-precision echo sounder-digitizer, which logs changes in the position of the sediment-water interface produced by erosion or deposition. The same procedure can be used in capping or dredging projects to track bottom changes as they occur, or they can be measured by pre- and post-project mapping of bathymetry and morphology with sweep-sonar or side-scan sonar equipment. The new equipment and procedures have been successfully applied to a number of areas of concern in the Great Lakes basin. They provide a faster and more detailed characterization of sediment properties and geometry than was previously available, and have been particularly effective in optimizing sampling surveys and monitoring remediation projects.

  10. Contaminated sediments database for the Gulf of Maine

    USGS Publications Warehouse

    Buchholtz ten Brink, M. R.; Manheim, F. T.; Mecray, E.L.; Hastings, M.E.; Currence, J.M.; Farrington, J.W.; Jones, S.H.; Larsen, P.F.; Tripp, B.W.; Wallace, G.T.; Ward, L.G.; Fredette, T.J.; Liebman, M.L.; Smith Leo, W.

    2002-01-01

    Bottom sediments in the Gulf of Maine and its estuaries have accumulated pollutants of many types, including metals and organic compounds of agricultural, industrial, and household derivation. Much analytical and descriptive data has been obtained on these sediments over the past decades, but only a small effort had been made, prior to this project, to compile and edit the published and unpublished data in forms suitable for a variety of users. The Contaminated Sediments Database for the Gulf of Maine provides a compilation and synthesis of existing data to help establish the environmental status of our coastal sediments and the transport paths and fate of contaminants in this region. This information, in turn, forms one of the essential bases for developing successful remediation and resource management policies.

  11. Simulation of contaminated sediment transport in White Oak Creek basin

    SciTech Connect

    Bao, Y.; Clapp, R.B.; Brenkert, A.L.; Moore, T.D.; Fontaine, T.A.

    1995-12-31

    This paper presents a systematic approach to management of the contaminated sediments in the White Oak Creek watershed at Oak Ridge National Laboratory near Oak Ridge, Tennessee. The primary contaminant of concern is radioactive cesium-137 ({sup 137}Cs), which binds to soil and sediment particles. The key components in the approach include an intensive sampling and monitoring system for flood events; modeling of hydrological processes, sediment transport, and contaminant flux movement; and a decision framework with a detailed human health risk analysis. Emphasis is placed on modeling of watershed rainfall-runoff and contaminated sediment transport during flooding periods using the Hydrologic Simulation Program- Fortran (HSPF) model. Because a large number of parameters are required in HSPF modeling, the major effort in the modeling process is the calibration of model parameters to make simulation results and measured values agree as closely as possible. An optimization model incorporating the concepts of an expert system was developed to improve calibration results and efficiency. Over a five-year simulation period, the simulated flows match the observed values well. Simulated total amount of sediment loads at various locations during storms match with the observed values within a factor of 1.5. Simulated annual releases of {sup 137}Cs off-site locations match the data within a factor of 2 for the five-year period. The comprehensive modeling approach can provide a valuable tool for decision makers to quantitatively analyze sediment erosion, deposition, and transport; exposure risk related to radionuclides in contaminated sediment; and various management strategies.

  12. Radioactive contamination of fish, shellfish, and waterfowl exposed to Hanford effluents: Annual summaries, 1945--1972

    SciTech Connect

    Hanf, R.W.; Dirkes, R.L.; Duncan, J.P.

    1992-07-01

    The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly summaries will be helpful to individuals and organizations interested in evaluating aquatic pathway information for locations impacted by Hanford operations and will be useful for planning the direction of future HEDR studies.

  13. Variations of common riverine contaminants in reservoir sediments.

    PubMed

    Micić, V; Kruge, M A; Hofmann, T

    2013-08-01

    Organic molecules in reservoir sediments can be used as tracers of contaminant inputs into rivers. Vertical variations in the molecular records can be ascribed to pre-depositional alteration within the water column, or in situ post-depositional alteration. We report the molecular stratigraphy of four common riverine contaminant groups in sediment of the largest reservoir on the Danube River, the Iron Gate I Reservoir. Sediments were rapidly deposited, with little variation in texture and, as revealed by analytical pyrolysis, in the concentration and composition of natural sedimentary organic matter. However, a detailed molecular inspection did reveal differences in distribution and organic carbon (OC)-normalized concentrations of contaminants. The OC-normalized concentrations of nonylphenol increased by one order of magnitude with depth down the 70 cm sediment core. There is a strong correlation between sediment depth and the ratio of nonylphenol to its precursor (nonylphenol monoethoxylate). This indicated that nonylphenol was produced in situ. While the relative proportions of C10-C14 linear alkylbenzenes remained constant with increasing depth, they exhibited variations in isomer distribution. These variations, which are due to different degrees of degradation, appear to have occurred within the water column prior to sedimentation of suspended solids. The distribution of 40 polycyclic aromatic hydrocarbons revealed origins from both pyrogenic and petrogenic sources. The differences in their compositions were not depth-related, but rather were associated with variations in the sorption capacities of texturally different sediments. Perylene showed slightly higher concentrations at greater depths, while the OC-normalized concentration of retene systematically increased with sediment depth. This is consistent with formation of retene and perylene via very early diagenetic transformation. The presence of petroleum biomarkers indicated minor contamination by fossil

  14. Fixation Mechanisms and Desorption Rates of Sorbed Cs in High-Level Waste Contaminated Subsurface Sediments: Implications to Future Behavior and In-Ground Stability

    SciTech Connect

    Zachara, John M.; McKinley, James P.; Ainsworth, Calvin C.; Serne, R. Jeff

    2002-06-01

    Research is investigating mineralogic and geochemical factors controlling the desorption rate of 137Cs+ from subsurface sediments on the Hanford Site contaminated with different types of high level waste. The project will develop kinetic data and models that describe the release rates of 137Cs+ from contaminated sediments over a range of potential geochemical conditions that may evolve during waste retrieval from overlying tanks, or in response to meteoric water infiltration. Scientific understanding and computational techniques will be established to predict the future behavior of sorbed, in-ground 137Cs+.

  15. Carbon Tetrachloride Partition Coefficients Measured by Aqueous Sorption to Hanford Sediments from Operable Units 200-UP-1 and 200-ZP-1

    SciTech Connect

    Wellman, Dawn M.; Riley, Robert G.; Cordova, Elsa A.; Parker, Kent E.; Mitroshkov, Alexandre V.

    2007-09-30

    Kd values obtained on sediment samples from 200-UP-1 and 10-ZP-1 contribute to a larger Kd database that exists for other Hanford sediments, and contains significant desorption data for CCl4. Adsorption results presented here validate the use of a linear adsorption isotherm (Kd) to predict short contact time CCl4 adsorption to sediments in 200-UP-1 groundwater plume for a distinct ranges in CCl4 concentration. However, this does not imply that values of Kd will be constant if the groundwater chemical composition at 200-UP-1 changes with space or time. Additionally, results presented here suggest the potential significance of slower intraparticle diffusion on the long-term fate of CCl4 within the subsurface Hanford environment. Such behavior could afford prolonged desorption of CCl4 and serve as a long-term source of contaminant CCl4 to the aquifer. Further evaluation of possible bimodal sorption behavior for CCl4 and the mechanism of CCl¬4 sequestration should be the subject of future investigations to provide a thorough, mechanistic understanding of the retention and long-term fate of CCl4. Comparison of previous data with new results (e.g., from this study) will allow inferences to be made on how the 200-UP-1 Kd values for CCl4 may compare with sediments from other Hanford locations. This site-specific sorption data, when complemented by the chemical, geologic, mineralogic, hydrologic, and physical characterization data that are also being collected (see Sampling and Analysis Plan for the 200-UP-1 Groundwater Monitoring Well Network, DOE 2002) can be used to develop a robust, scientifically defensible data base to allow risk predictions to be generated and to aid in future remediation decisions for the 200-UP-1 and 200-ZP-1 operable units.

  16. Metal contamination of estuarine intertidal sediments of Moreton Bay, Australia.

    PubMed

    Morelli, Guia; Gasparon, Massimo

    2014-12-15

    Trace element concentrations in surface intertidal sediments were analyzed to assess the level of contamination along the western side of Moreton Bay (Australia). The environmental risks posed by metals were evaluated using sediment quality guidelines, the Risk Assessment Code (RAC) and enrichment relative to background levels. Chromium, Ni, and Cu are the main contributors to sediment pollution. Sediments are also enriched in Zn, Cd and Pb by 1.5-3 times the regional background. Zinc, Cd and Co may pose high to very high risk to the aquatic biota due to their potential bioavailability, while Ni, As, Cu, Pb and Cr may pose medium risk at some of the investigated sites. Results emphasize the importance of using different methods for the assessment of sediment pollution at an estuarine site.

  17. Characterizing toxicity of metal-contaminated sediments from mining areas

    USGS Publications Warehouse

    Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.

    2015-01-01

    This paper reviews methods for testing the toxicity of metals associated with freshwater sediments, linking toxic effects with metal exposure and bioavailability, and developing sediment quality guidelines. The most broadly applicable approach for characterizing metal toxicity is whole-sediment toxicity testing, which attempts to simulate natural exposure conditions in the laboratory. Standard methods for whole-sediment testing can be adapted to test a wide variety of taxa. Chronic sediment tests that characterize effects on multiple endpoints (e.g., survival, growth, and reproduction) can be highly sensitive indicators of adverse effects on resident invertebrate taxa. Methods for testing of aqueous phases (pore water, overlying water, or elutriates) are used less frequently. Analysis of sediment toxicity data focuses on statistical comparisons between responses in sediments from the study area and responses in one or more uncontaminated reference sediments. For large or complex study areas, a greater number of reference sediments is recommended to reliably define the normal range of responses in uncontaminated sediments – the ‘reference envelope’. Data on metal concentrations and effects on test organisms across a gradient of contamination may allow development of concentration-response models, which estimate metal concentrations associated with specified levels of toxic effects (e.g. 20% effect concentration or EC20). Comparisons of toxic effects in laboratory tests with measures of impacts on resident benthic invertebrate communities can help document causal relationships between metal contamination and biological effects. Total or total-recoverable metal concentrations in sediments are the most common measure of metal contamination in sediments, but metal concentrations in labile sediment fractions (e.g., determined as part of selective sediment extraction protocols) may better represent metal bioavailability. Metals released by the weak-acid extraction

  18. Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

    SciTech Connect

    Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

    1987-12-01

    An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs.

  19. Hydrogeologic controls on ground-water and contaminant discharge to the Columbia River near the Hanford Townsite

    SciTech Connect

    Luttrell, S.P.; Newcomer, D.R.; Teel, S.S.; Vermeul, V.R.

    1992-11-01

    The purpose of this study is to quantify ground-water and contaminant discharge to the Columbia River in the Hanford Townsite vicinity. The primary objectives of the work are to: describe the hydrogeologic setting and controls on ground-water movement and contaminant discharge to the Columbia River; understand the river/aquifer relationship and its effects on contaminant discharge to the Columbia River; quantify the ground-water and contaminant mass discharge to the Columbia River; and provide data that may be useful for a three-dimensional model of ground-water flow and contaminant transport in the Hanford Townsite study area. The majority of ground-water contamination occurs within the unconfined aquifer; therefore, ground-water and contaminant discharge from the unconfined aquifer is the emphasis of this study. The period of study is primarily from June 1990 through March 1992.

  20. NATIONAL CONFERENCE ON MANAGEMENT AND TREATMENT OF CONTAMINATED SEDIMENTS: PROCEEDINGS

    EPA Science Inventory

    The National Conference on Management and Treatment of Contaminated Sediment was held in Cincinnati, OH, May 13 to 14, 1997. This technology transfer meeting was held for 213 professionals from various EPA divisions and other organizations, including Environment Canada, the U.S. ...

  1. Mercury Contaminated Sediment Sites: A Review Of Remedial Solutions

    EPA Science Inventory

    Mercury (Hg) can accumulate in sediment from point and non-point sources, depending on a number of physical, chemical, biological, geological and anthropogenic environmental processes. It is believed that the associated Hg contamination in aquatic systems can be decreased by imp...

  2. Test system for exposing fish to resuspended, contaminated sediment

    USGS Publications Warehouse

    Cope, W.G.; Wiener, J.G.; Steingraeber, M.T.

    1996-01-01

    We describe a new test system for exposing fish to resuspended sediments and associated contaminants. Test sediments were resuspended by revolving test chambers on rotating shafts driven by an electric motor. The timing, speed, and duration of test-chamber revolution were controlled by a rheostat and electronic timer. Each chamber held 45 litres of water and accommodated about 49 g of test fish. The system described had three water baths, each holding six test chambers. We illustrate the performance of this system with results from a 28-day test in which juvenile bluegills Lepomis macrochirus were exposed to resuspended, riverine sediments differing in texture and cadmium content. The test had one sediment-free control and five sediment treatments, with three replicates (chambers) per treatment and 25 fish per replicate. Two-thirds (30 litres) of the test water and sediment in each chamber was renewed weekly. The mean concentration of total suspended solids (TSS) did not vary among treatments; the grand-mean TSS in the five sediment treatments was 975 mg litre-1, similar to the target TSS of 1000 mg litre-1. At the end of the test, an average of 50% of the introduced cadmium was associated with the suspended sediment compartment, whereas the filtered (0.45 μm) water contained 0.4% and bluegills 1.8% of the cadmium.

  3. Indices of benthic community tolerance in contaminated Great Lakes sediments: Relations with sediment contaminant concentrations, sediment toxicity, and the sediment quality triad

    USGS Publications Warehouse

    Wildhaber, M.L.; Schmitt, C.J.

    1998-01-01

    We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls - PCBs, polycyclic aromatic hydrocarbons PAHs, pesticides, chlorinated dioxins, and metals). Sediment toxic units were defined as the ratio of the estimated pore-water concentration of a contaminant to its chronic toxicity as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC) or other applicable standard. The total hazard of a sediment to aquatic life was assessed by summing toxic units for all contaminants quantified. Among the benthic community metrics evaluated, total toxic units were most closely correlated with Lenat's (1993) and Hilsenhoff's (1987) indices of community tolerance (T(L), and T(H), respectively); toxic units accounted for 42% (T(L)) and 53% (T(H)) of variability in community tolerance as measured by Ponar grabs. In contrast, taxonomic richness and Shannon-Wiener diversity were not correlated (P > 0.05) with toxic units. Substitution of order- or family-level identifications for lowest possible (mostly genus- or species-) level identifications in the calculation of T(L) and T(H) indices weakened the relationships with toxic units. Tolerance values based on order- and family-level identifications of benthos for artificial substrate samples were more strongly correlated with toxic units than tolerance values for benthos from Ponar grabs. The ability of the toxic-units model to predict the other two components (i.e., laboratory-measured sediment toxicity and benthic community composition) of the Sediment Quality Triad (SQT) may obviate the need for the SQT in some situations.

  4. Remobilisation of uranium from contaminated freshwater sediments by bioturbation

    NASA Astrophysics Data System (ADS)

    Lagauzère, S.; Motelica-Heino, M.; Viollier, E.; Stora, G.; Bonzom, J. M.

    2014-06-01

    Benthic macro-invertebrate bioturbation can influence the remobilisation of uranium (U) initially associated with freshwater sediments, resulting in a high release of this pollutant through the overlying water column. Given the potential negative effects on aquatic biocenosis and the global ecological risk, it appears crucial to improve our current knowledge concerning the biogeochemical behaviour of U in sediments. The present study aimed to assess the biogeochemical modifications induced by Tubifex tubifex (Annelida, Clitellata, Tubificidae) bioturbation within the sediment in order to explain such a release of U. To reach this goal, U distribution between solid and solute phases of a reconstructed benthic system (i.e. in mesocosms) inhabited or not by T. tubifex worms was assessed in a 12-day laboratory experiment. Thanks notably to fine-resolution (mm-scale) measurements (e.g. "diffusive equilibrium in thin-films" DET gel probes for porewater, bioaccumulation in worms) of U and main chemical species (iron, sulfate, nitrate and nitrite), this work (i) confirmed that the removal of bottom sediment particles to the surface through the digestive tract of worms greatly favoured oxidative loss of U in the water column, and (ii) demonstrated that both U contamination and bioturbation of T. tubifex substantially influenced major microbial-driven biogeochemical reactions in sediments (e.g. stimulation of denitrification, sulfate reduction and iron dissolutive reduction). This study provides the first demonstration of biogeochemical modifications induced by bioturbation in freshwater U-contaminated sediments.

  5. Remobilisation of uranium from contaminated freshwater sediments by bioturbation

    NASA Astrophysics Data System (ADS)

    Lagauzère, S.; Motelica-Heino, M.; Viollier, E.; Stora, G.; Bonzom, J. M.

    2013-10-01

    Previous studies have demonstrated that benthic macro-invertebrate bioturbation can influence the remobilization of uranium initially associated with freshwater sediments resulting in a high release of this pollutant through the overlying water column. Giving the potential negative effects on aquatic biocenosis and the global ecological risk, it appeared crucial to improve our current knowledge concerning the uranium biogeochemical behaviour in sediments. The present study aimed to assess the biogeochemical modifications induced by Tubifex tubifex (Annelida, Clitellata, Tubificidae) bioturbation within the sediment permitting to explain such a release of uranium. To reach this goal, uranium distribution between solid and solute phases of a reconstructed benthic system (i.e. in mesocosms) inhabited or not by T. tubifex worms was assessed in a 12 day laboratory experiment. Thanks notably to fine resolution (mm-scale) measurements (e.g. DET gels probes for porewater, bioaccumulation in worms) of uranium and main chemical species (iron, sulfate, nitrate, nitrite), this work permitted (i) to confirm that the removal of bottom sediment particles to the surface through the digestive tract of worms greatly favours the oxidative loss of uranium in the water column, and (ii) to demonstrate that both uranium contamination and bioturbation of T. tubifex substantially influence major microbial-driven biogeochemical reactions in sediments (e.g. stimulation of denitrification, sulfate-reduction and iron dissolutive reduction). This study provides the first demonstration of biogeochemical modifications induced by bioturbation in freshwater uranium-contaminated sediments.

  6. Tracing mercury contamination sources in sediments using mercury isotope compositions.

    PubMed

    Feng, Xinbin; Foucher, Delphine; Hintelmann, Holger; Yan, Haiyu; He, Tianrong; Qiu, Guangle

    2010-05-01

    Mercury (Hg) isotope ratios were determined in two sediment cores collected from two adjacent reservoirs in Guizhou, China, including Hongfeng Reservoir and Baihua Reservoir. Hg isotope compositions were also analyzed in a soil sample collected from the catchment of Hongfeng Reservoir and three cinnabar samples collected from the Wanshan Hg mine. Baihua Reservoir was contaminated with runoff from Guizhou Organic Chemical Plant (GOCP) when metallic Hg was used as a catalyst to produce acetic acid. Hongfeng Reservoir, located upstream of Baihua, receives Hg from runoff and atmospheric deposition. We demonstrated that delta(202)Hg values relative to NIST 3133 of sediment in Baihua Reservoir ranging from -0.60 to -1.10 per thousand were distinctively different from those in Hongfeng Reservoir varying from -1.67 to -2.02 per thousand. While sediments from both Baihua and Hongfeng Reservoirs were characterized by mass dependent variation (MDF), only Hongfeng Reservoir sediments were characterized by mass independent variation (MIF). Moreover, by using a binary mixing model, we demonstrated the major source of Hg in sediment of Hongfeng Reservoir was from runoff due to soil erosion, which was consistent with the conclusion obtained from a previous Hg balance study. This study demonstrates Hg isotope data are valuable tracers for determining Hg contamination sources in sediments.

  7. Assessment of potential impacts of major groundwater contaminants to fall chinook salmon (Oncorhynchus tshawytscha) in the Hanford Reach, Columbia River

    SciTech Connect

    Geist, D.R.; Poston, T.M.; Dauble, D.D.

    1994-10-01

    Past operations of Hanford Site facilities have contaminated the groundwater adjacent to the Hanford Reach of the Columbia River, Washington, with various chemical and radiological constituents. The groundwater is hydraulically connected to the river and contains concentrations of contaminants that sometimes exceed federal and/or state drinking water standards or standards for the protection of aquatic life. For example, concentrations of chromium in shoreline seeps and springs at most 100 Area operable units exceed concentrations found to be toxic to fish. Nitrate and tritium concentrations in shoreline seeps are generally below drinking water standards and concentrations potentially toxic to aquatic life, but nitrate concentrations may be high enough to synergistically interact with and exacerbate chromium toxicity. The Hanford Reach also supports the largest run of fall chinook salmon (Oncorhynchus tshawytscha) in the Columbia River Basin. Numbers of fall chinook salmon returning to the Hanford Reach have increased relative to other mainstem populations during the last 30 years. Groundwater discharge appears to occur near some salmon spawning areas, but contaminants are generally not detectable in surface water samples. The concentration and potential toxicity of contaminants in the interstitial waters of the substrate where fall chinook salmon embryogenesis occurs are presently unknown. New tools are required to characterize the extent of groundwater contaminant discharge to the Hanford Reach and to resolve uncertainties associated with assessment of potential impacts to fall chinook salmon.

  8. Mineralogic Residence and Desorption Rates of Sorbed 90Sr in Contaminated Subsurface Sediments: Implications to Future Behavior and In-Ground Stability

    SciTech Connect

    Peter C. Lichtner

    2006-06-01

    90Sr desorption process will be quantified in coarse-textured Hanford sediments contaminated by different waste types and a reaction-based reactive transport model developed to forecast 90Sr concentration dynamics in Hanford's 100-N plume. Previous research has addressed 137Cs desorption from HLW-contaminated sediment providing results critical for HLW tank farm closure decisions. This renewal focuses on 90Sr with the objective of providing fundamental knowledge to predict future in-ground behavior as required for sound remedial decisions. Preliminary observations that suggest that 10-y sorbed 90Sr in coarse-textured sediment resides in the interiors of basaltic lithic fragments. This intraparticle retention defines a new conceptual model for 90Sr retardation that is tentatively attributed to internal domains of phyllosilicates formed from the weathering of basaltic glass. Research will characterize the spatial locations, composition, and reactivity of these intragrain phyllosilicate domains using spectroscopic, microscopic, and wet chemical methods. Intragrain porosity, diffusivity, and tortuosity will be estimated using emersion experiments coupled with particle imaging (using electron, X-ray, and NMR techniques). Desorption rates and extent will be measured from contaminated Hanford sediments of different waste impact in electrolytes that promote isotopic exchange, ion exchange, and/or dissolution. Desorption results will be interpreted with a geochemical-physical model that incorporates aqueous speciation, mass transfer, and other important factors. Batch and column experiments will be performed with sediments from Hanfords 100-N plume to quantify factors controlling long-term release rates and river stage effects. Newfound understanding and geochemical parameters will be incorporated into the FLOTRAN reactive transport code for simulation of 100-N plume dynamics.

  9. EVALUATION OF BIOAEROSOL COMPONENTS, GENERATION FACTORS, AND AIRBORNE TRANSPORT ASSOCIATED WITH LIME TREATMENT OF CONTAMINATED SEDIMENT

    EPA Science Inventory

    Lime treatment has been used in contaminated sediment management activities for many purposes such as dewatering, improvement of physical properties, and reducing contaminant mobility. Exothermic volatilization of volatile organic compounds from lime-treated sediment is well kno...

  10. Characterization and Potential Remediation Approaches for Vadose Zone Contamination at Hanford 241-SX Tank Farm

    SciTech Connect

    Eberlein, Susan J.; Sydnor, Harold A.; Parker, Danny L.; Glaser, Danney R.

    2013-01-10

    Unplanned releases of radioactive and hazardous wastes have occurred at the 241-SX Tank Farm on the U.S. Department of Energy Hanford Site in southeast Washington State. Interim and long-term mitigation efforts are currently under evaluation for 241-SX Tank Farm. Two contiguous interim surface barriers have been designed for deployment at 241-SX Tank Farm to reduce future moisture infiltration; however, construction of the surface barriers has been deferred to allow testing of alternative technologies for soil moisture reduction and possibly contaminant source term reduction. Previous tests performed by other organizations at the Hanford Site have demonstrated that: vadose zone desiccation using large diameter (greater than 4 inch) boreholes is feasible; under certain circumstances, mobile contaminants may be removed in addition to water vapor; and small diameter (approximately 2 inch) boreholes (such as those placed by the direct push hydraulic hammer) can be used to perform vapor extractions. Evaluation of the previous work combined with laboratory test results have led to the design of a field proof-of-principle test to remove water and possibly mobile contaminants at greater depths, using small boreholes placed with the direct push unit.

  11. Characterization and Potential Remediation Approaches for Vadose Zone Contamination at Hanford 241-SX Tank Farm - 13235

    SciTech Connect

    Eberlein, Susan J.; Sydnor, Harold A.; Parker, Danny L.; Glaser, Danney R.

    2013-07-01

    Unplanned releases of radioactive and hazardous wastes have occurred at the 241-SX Tank Farm on the U.S. Department of Energy Hanford Site in southeast Washington State. Interim and long-term mitigation efforts are currently under evaluation for 241-SX Tank Farm. Two contiguous interim surface barriers have been designed for deployment at 241-SX Tank Farm to reduce future moisture infiltration; however, construction of the surface barriers has been deferred to allow testing of alternative technologies for soil moisture reduction and possibly contaminant source term reduction. Previous tests performed by other organizations at the Hanford Site have demonstrated that: vadose zone desiccation using large diameter (greater than 4 inch) boreholes is feasible; under certain circumstances, mobile contaminants may be removed in addition to water vapor; and small diameter (approximately 2 inch) boreholes (such as those placed by the direct push hydraulic hammer) can be used to perform vapor extractions. Evaluation of the previous work combined with laboratory test results have led to the design of a field proof-of-principle test to remove water and possibly mobile contaminants at greater depths, using small boreholes placed with the direct push unit. (authors)

  12. Field Summary Report for Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington

    SciTech Connect

    L.C. Hulstrom

    2010-08-11

    This report summarizes field sampling activities conducted in support of WCH’s Remedial Investigation of Hanford Site Releases to the Columbia River. This work was conducted form 2008 through 2010. The work included preliminary mapping and measurement of Hanford Site contaminants in sediment, pore water, and surface water located in areas where groundwater upwelling were found.

  13. Field Summary Report for Remedial Investigation of Hanford Site Releases to the Coumbia River, Hanford Site, Washington

    SciTech Connect

    L.C. Hulstrom

    2010-11-10

    This report summarizes field sampling activities conducted in support of WCH’s Remedial Investigation of Hanford Site Releases to the Columbia River. This work was conducted form 2008 through 2010. The work included preliminary mapping and measurement of Hanford Site contaminants in sediment, pore water, and surface water located in areas where groundwater upwelling were found.

  14. A PHYSICAL, CHEMICAL, AND BIOLOGICAL ASSESSMENT OF MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, NC

    EPA Science Inventory

    Management of contaminated sediments poses significant challenges due to varied contaminants and volumes of sediments to manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks. Understanding how eff...

  15. PHYSICAL, CHEMICAL AND BIOLOGICAL TOOLS FOR EVALUATING, MONITORED NATURAL RECOVERY OF PCB CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC

    EPA Science Inventory

    Management of contaminated sediments poses significant challenges due to varied contaminants and volumes of sediments to
    manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks.
    Understanding ho...

  16. Uranium in Hanford Site 300 Area: Extraction Data on Borehole Sediments

    SciTech Connect

    Wang, Guohui; Serne, R. Jeffrey; Lindberg, Michael J.; Um, Wooyong; Bjornstad, Bruce N.; Williams, Benjamin D.; Kutynakov, I. V.; Wang, Zheming; Qafoku, Nikolla

    2012-11-26

    In this study, sediments collected from boreholes drilled in 2010 and 2011 as part of a remedial investigation/feasibility study were characterized. The wells, located within or around two process ponds and one process trench waste site, were characterized in terms of total uranium concentration, mobile fraction of uranium, particle size, and moisture content along the borehole depth. In general, the gravel-dominated sediments of the vadose zone Hanford formation in all investigated boreholes had low moisture contents. Based on total uranium content, a total of 48 vadose zone and periodically rewetted zone sediment samples were selected for more detailed characterization, including measuring the concentration of uranium extracted with 8 M nitric acid, and leached using bicarbonate mixed solutions to determine the liable uranium (U(VI)) contents. In addition, water extraction was conducted on 17 selected sediments. Results from the sediment acid and bicarbonate extractions indicated the total concentrations of anthropogenic labile uranium in the sediments varied among the investigated boreholes. The peak uranium concentration (114.84 µg/g, acid extract) in <2-mm size fractions was found in borehole 399 1-55, which was drilled directly in the southwest corner of the North Process Pond. Lower uranium concentrations (~0.3–2.5 µg/g, acid extract) in <2-mm size fractions were found in boreholes 399-1-57, 399-1-58, and 399-1-59, which were drilled either near the Columbia River or inland and upgradient of any waste process ponds or trenches. A general trend of “total” uranium concentrations was observed that increased as the particle size decreased when relating the sediment particle size and acid extractable uranium concentrations in two selected sediment samples. The labile uranium bicarbonate leaching kinetic experiments on three selected sediments indicated a two-step leaching rate: an initial rapid release, followed by a slow continual release of uranium from

  17. The effect of depositional history on contaminated bed sediment stability.

    PubMed

    Droppo, I G; Lau, Y L; Mitchell, C

    2001-02-01

    Experiments were conducted in an annular flume using a commercially available kaolinite clay as well as contaminated bed sediment from Hamilton Harbour (Ontario) to assess their stability against erosion. Critical shear stress for erosion was measured under different conditions of bed formation (quiescently deposited beds and shear deposited beds) as well as with and without the presence of a biostabilized bed. Results suggest that a biostabilized bed and a bed formed under a flowing condition, similar to a river scenario, will be more resistant against erosion than will a non-biostabilized bed and a bed formed under quiescent conditions. Up to three cycles of erosion and flocculation/deposition were observed to occur within one experiment. These results suggest that the depositional history and biostabilization of river bed sediments need to be seriously considered within sediment and contaminant transport models if meaningful estimates of sediment and contaminant source, fate and effect are to be generated and used for the management of our aquatic ecosystems.

  18. UPTAKE AND DEPURATION OF NON-IONIC ORGANIC CONTAMINANTS FROM SEDIMENT BY THE OLIGOCHAETE, LUMBRICULUS VARIEGATUS

    EPA Science Inventory

    Uptake of sediment-associated contaminants by the oligochaete, Lumbriculus variegatus, was evaluated after 1,3,7,14,28, and 56 d of exposure to a field-collected sediment contaminated with DDT and its metabolites DDD and DDE or to a field-collected sediment contaminated with PAHs...

  19. Investigation of the Strontium-90 Contaminant Plume along the Shoreline of the Columbia River at the 100-N Area of the Hanford Site

    SciTech Connect

    Mendoza, Donaldo P.; Patton, Gregory W.; Hartman, Mary J.; Spane, Frank A.; Sweeney, Mark D.; Fritz, Brad G.; Gilmore, Tyler J.; Mackley, Rob D.; Bjornstad, Bruce N.; Clayton, Ray E.

    2007-10-01

    Efforts are underway to remediate strontium-laden groundwater to the Columbia River at the 100-N Area of the Hanford Site. Past practices of the 100-N reactor liquid waste disposal sites has left strontium-90 sorbed onto sediments which is a continuing source of contaminant discharge to the river. The Remediation Task of the Science and Technology Project assessed the interaction of groundwater and river water at the hyporheic zone. Limited data have been obtained at this interface of contaminant concentrations, geology, groundwater chemistry, affects of river stage and other variables that may affect strontium-90 release. Efforts were also undertaken to determine the extent, both laterally and horizontally, of the strontium-90 plume along the shoreline and to potentially find an alternative constituent to monitor strontium-90 that would be more cost effective and could possibly be done under real time conditions. A baseline of strontium-90 concentrations along the shoreline was developed to help assess remediation technologies.

  20. Geomorphological assessment of sediment contamination in an urban stream system

    USGS Publications Warehouse

    Rhoads, B.L.; Cahill, R.A.

    1999-01-01

    Little is known about the influence of fluvial-geomorphological features on the dispersal of sediment-related contaminants in urban drainage systems. This study investigates the relation between reach-scale geomorphological conditions and network-scale patterns of trace-element concentrations in a partially urbanized stream system in East-Central Illinois, USA Robust statistical analysis of bulk sediment samples reveals levels of Cr, Cu, Pb, Ni, and Zn exceed contamination thresholds in the portion of the watershed in close proximity to potential sources of pollution-in this case storm-sewer outfalls. Although trace-element concentrations decrease rapidly downstream from these sources, substantial local variability in metal levels exists within contaminated reaches. This local variability is related to reach-scale variation in fluvial-geomorphic conditions, which in turn produces variation in the degree of sorting and organic-matter content of bed material. Metal concentrations at contaminated sites also exhibit considerable variability over time. Analytical tests on specific size fractions of material collected at a highly contaminated site indicate that Cr and Ni are concentrated in the 0.063 to 0.250 mm fraction of the sediment. This fraction also has elevated concentration of Zr. SEM analysis shows that the fine sand fraction contains shards of stainless steel within a matrix of zircon sand, an industrial material associated with a nearby alloy casting operation. Samples of suspended load and bedload at the contaminated site also have elevated amounts of trace metals, but concentrations of Ni and Cr in the bedload are less than concentrations in the bed material, suggesting that these trace elements are relatively immobile. Off the other hand, amounts of CU and Zn in the bedload exceed concentrations in the bed material, implying that these trace metals are preferentially mobilized during transport events.

  1. Hanford Tanks 241-C-202 and 241-C-203 Residual Waste Contaminant Release Models and Supporting Data

    SciTech Connect

    Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Mattigod, Shas V.; Schaef, Herbert T.; Arey, Bruce W.

    2007-09-13

    As directed by Congress, the U. S. Department of Energy (DOE) established the Office of River Protection in 1998 to manage DOE's largest, most complex environmental cleanup project – retrieval of radioactive waste from Hanford tanks for treatment and eventual disposal. Sixty percent by volume of the nation's high-level radioactive waste is stored at Hanford in aging deteriorating tanks. If not cleaned up, this waste is a threat to the Columbia River and the Pacific Northwest. CH2M Hill Hanford Group, Inc., is the Office of River Protection's prime contractor responsible for the storage, retrieval, and disposal of Hanford's tank waste. As part of this effort, CH2M HILL Hanford Group, Inc. contracted with Pacific Northwest National Laboratory (PNNL) to develop release models for key contaminants that are present in residual sludge remaining after closure of Hanford Tanks 241-C-203 (C-203) and 241-C-204 (C-204). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. These release models are being developed to support the tank closure risk assessments performed by CH2M HILL Hanford Group, Inc., for DOE.

  2. LONG-TERM RECOVERY OF PCB-CONTAMINATED SURFACE SEDIMENTS AT THE SANGAMO-WESTON/TWELVEMILE CREEK/LAKE HARTWELL SUPERFUND SITE

    EPA Science Inventory

    Natural recovery of contaminated sediments relies on burial of contaminated sediments with increasingly clean sediments over time (i.e., natural capping). Natural capping reduces the risk of resuspension of contaminated surface sediments, and it reduces the potential for contamin...

  3. Characterizing Water, Sediment, Nutrients, and Contaminant Fluxes in Coastal Egypt

    NASA Astrophysics Data System (ADS)

    Peterson, Richard N.; El-Gamal, Ayman

    2010-03-01

    Marine Constituent Dynamics in Coastal Egypt; Alexandria, Egypt, 20 November 2009; The Egyptian coastal area is a highly dynamic region in which materials (water, sediment, nutrients, and contaminants) are transported from various sources to the Mediterranean and Red seas. At a workshop in Egypt, U.S. and Egyptian scientists discussed these largely unquantified processes and how they interact to drive coastal ecology. A major goal of the workshop was to identify the most pressing research priorities for the region for both scientific and management purposes. The workshop concluded by recommending that international multidisciplinary efforts be undertaken to characterize water, nutrient, sediment, and contaminant delivery fluxes and mechanisms to coastal regions of the Nile Delta.

  4. COPING WITH CONTAMINATED SEDIMENTS AND SOILS IN THE URBAN ENVIRONMENT.

    SciTech Connect

    JONES,K.W.; VAN DER LELIE,D.; MCGUIGAN,M.; ET AL.

    2004-05-25

    Soils and sediments contaminated with toxic organic and inorganic compounds harmful to the environment and to human health are common in the urban environment. We report here on aspects of a program being carried out in the New York/New Jersey Port region to develop methods for processing dredged material from the Port to make products that are safe for introduction to commercial markets. We discuss some of the results of the program in Computational Environmental Science, Laboratory Environmental Science, and Applied Environmental Science and indicate some possible directions for future work. Overall, the program elements integrate the scientific and engineering aspects with regulatory, commercial, urban planning, local governments, and community group interests. Well-developed connections between these components are critical to the ultimate success of efforts to cope with the problems caused by contaminated urban soils and sediments.

  5. Fe-phyllosilicate redox cycling organisms from a redox transition zone in Hanford 300 Area sediments

    SciTech Connect

    Benzine, Jason; Shelobolina, Evgenya S.; Xiong, Mai Yia; Kennedy, David W.; McKinley, James P.; Lin, Xueju; Roden, Eric E.

    2013-01-01

    Microorganisms capable of reducing or oxidizing structural iron (Fe) in Fe-bearing phyllosilicate minerals were enriched and isolated from a subsurface redox transition zone at the Hanford 300 Area site in eastern Washington, USA. Both conventional and in situ "i-chip" enrichment strategies were employed. One Fe(III)-reducing Geobacter (G. bremensis strain R1, Deltaproteobacteria) and six Fe(II) phyllosilicate-oxidizing isolates from the Alphaproteobacteria (Bradyrhizobium japonicum strains 22, is5, and in8p8), Betaproteobacteria (Cupriavidus necator strain A5-1, Dechloromonas agitata strain is5), and Actinobacteria (Nocardioides sp. strain in31) were recovered. The G. bremensis isolate grew by oxidizing acetate with the oxidized form of NAu-2 smectite as the electron acceptor. The Fe(II)-oxidizers grew by oxidation of chemically reduced smectite as the energy source with nitrate as the electron acceptor. The Bradyrhizobium isolates could also carry out aerobic oxidation of biotite. This is the first report of the recovery of a Fe(II)-oxidizing Nocardioides, and to date only one other Fe(II)-oxidizing Bradyrhizobium is known. The 16S rRNA gene sequences of the isolates were similar to ones found in clone libraries from Hanford 300 sediments and groundwater, suggesting that such organisms may be present and active in situ. Whole genome sequencing of the isolates is underway, the results of which will enable comparative genomic analysis of mechanisms of extracellular phyllosilicate Fe redox metabolism, and facilitate development of techniques to detect the presence and expression of genes associated with microbial phyllosilicate Fe redox cycling in sediments.

  6. Effects of lead-contaminated sediment on Rana sphenocephala tadpoles

    USGS Publications Warehouse

    Sparling, D.W.; Krest, S.K.; Ortiz-Santaliestra, M.

    2006-01-01

    We exposed larval southern leopard frogs (Rana sphenocephala) to lead-contaminated sediments to determine the lethal and sublethal effects of this metal. Tadpoles were laboratory-raised from early free-swimming stage through metamorphosis at lead concentrations of 45, 75, 180, 540, 2360, 3940, 5520, and 7580 mg/kg dry weight in sediment. Corresponding pore water lead concentrations were 123, 227, 589, 1833, 8121, 13,579, 19,038, and 24,427 ug/L. Tadpoles exposed to lead concentrations in sediment of 3940 mg/kg or higher died within 2 to 5 days of exposure. At lower concentrations, mortality through metamorphosis ranged from 3.5% at 45 mg/kg lead to 37% at 2360 mg/kg lead in sediment. The LC50 value for lead in sediment was 3728 mg/kg (95% CI=1315 to 72,847 mg/kg), which corresponded to 12,539 ug/L lead in pore water (95% CI= 4000 to 35,200 ug/L). Early growth and development were depressed at 2,360 mg/kg lead in sediment (8100 ug/L in pore water) but differences were not evident by the time of metamorphosis. The most obvious effect of lead was its pronounced influence on skeletal development. Whereas tadpoles at 45 mg/kg lead in sediment did not display permanent abnormalities, skeletal malformations increased in frequency and severity at all higher lead concentrations. By 2360 mg/kg, 100% of surviving metamorphs displayed severe spinal problems, reduced femur and humerus lengths, deformed digits, and other bone malformations. Lead concentrations in tissues correlated positively with sediment and pore water concentrations.

  7. Active capping technology: a new environmental remediation of contaminated sediment.

    PubMed

    Zhang, Chang; Zhu, Meng-Ying; Zeng, Guang-Ming; Yu, Zhi-Gang; Cui, Fang; Yang, Zhong-Zhu; Shen, Liu-Qing

    2016-03-01

    The management and treatment of contaminated sediment is a worldwide problem and poses major technical and economic challenges. Nowadays, various attempts have been committed to investigating a cost-effective way in contaminated sediment restoration. Among the remediation options, in situ capping turns out to be a less expensive, less disruptive, and more durable approach. However, by using the low adsorption capacity materials, traditional caps do not always fulfill the reduction of risks that can be destructive for human health, ecosystem, and even natural resources. Active caps, therefore, are designed to employ active materials (activated carbon, apatite, zeolite, organoclay, etc.) to strengthen their adsorption and degradation capacity. The active capping technology promises to be a permanent and cost-efficient solution to contaminated sediments. This paper provides a review on the types of active materials and the ways of these active materials employed in recent active capping studies. Cap design considerations including site-specific conditions, diffusion/advection, erosive forces, and active material selection that should be noticed in an eligible remediation project are also presented. PMID:26762937

  8. Active capping technology: a new environmental remediation of contaminated sediment.

    PubMed

    Zhang, Chang; Zhu, Meng-Ying; Zeng, Guang-Ming; Yu, Zhi-Gang; Cui, Fang; Yang, Zhong-Zhu; Shen, Liu-Qing

    2016-03-01

    The management and treatment of contaminated sediment is a worldwide problem and poses major technical and economic challenges. Nowadays, various attempts have been committed to investigating a cost-effective way in contaminated sediment restoration. Among the remediation options, in situ capping turns out to be a less expensive, less disruptive, and more durable approach. However, by using the low adsorption capacity materials, traditional caps do not always fulfill the reduction of risks that can be destructive for human health, ecosystem, and even natural resources. Active caps, therefore, are designed to employ active materials (activated carbon, apatite, zeolite, organoclay, etc.) to strengthen their adsorption and degradation capacity. The active capping technology promises to be a permanent and cost-efficient solution to contaminated sediments. This paper provides a review on the types of active materials and the ways of these active materials employed in recent active capping studies. Cap design considerations including site-specific conditions, diffusion/advection, erosive forces, and active material selection that should be noticed in an eligible remediation project are also presented.

  9. Ecological effects of contaminated sediments following a decade of no industrial effluents emissions: the Sediment Quality Triad approach.

    PubMed

    Lopes, Marta Lobão; Rodrigues, Ana Maria; Quintino, Victor

    2014-10-15

    Sediments contaminated by industrial effluents a decade after the emissions were stopped were statistically compared to sediments from reference channels, using the Sediment Quality Triad approach. The metals and metalloid concentrations, mainly Hg and As, increased towards the upper part of a contaminated channel, where the industrial discharge was located. A bioaccumulation assay with Scrobicularia plana showed the highest bioaccumulation and mortality in the most contaminated sediments and bioaccumulation strongly correlated with the sediments metals and metalloid concentrations. The resident macroinvertebrate community also showed significant differences between the contaminated and reference channels, in the upper areas, where the community was most affected. All three elements of the quality triad rejected the null hypothesis and indicated that despite the emissions ceasing in 2004, sediments remain contaminated by high levels of metals and metalloid, leading to bioaccumulation and with severe community level consequences. PMID:25152187

  10. Groundwater contaminant plume maps and volumes, 100-K and 100-N Areas, Hanford Site, Washington

    USGS Publications Warehouse

    Johnson, Kenneth H.

    2016-09-27

    This study provides an independent estimate of the areal and volumetric extent of groundwater contaminant plumes which are affected by waste disposal in the 100-K and 100-N Areas (study area) along the Columbia River Corridor of the Hanford Site. The Hanford Natural Resource Trustee Council requested that the U.S. Geological Survey perform this interpolation to assess the accuracy of delineations previously conducted by the U.S. Department of Energy and its contractors, in order to assure that the Natural Resource Damage Assessment could rely on these analyses. This study is based on previously existing chemical (or radionuclide) sampling and analysis data downloaded from publicly available Hanford Site Internet sources, geostatistically selected and interpreted as representative of current (from 2009 through part of 2012) but average conditions for groundwater contamination in the study area. The study is limited in scope to five contaminants—hexavalent chromium, tritium, nitrate, strontium-90, and carbon-14, all detected at concentrations greater than regulatory limits in the past.All recent analytical concentrations (or activities) for each contaminant, adjusted for radioactive decay, non-detections, and co-located wells, were converted to log-normal distributions and these transformed values were averaged for each well location. The log-normally linearized well averages were spatially interpolated on a 50 × 50-meter (m) grid extending across the combined 100-N and 100-K Areas study area but limited to avoid unrepresentative extrapolation, using the minimum curvature geostatistical interpolation method provided by SURFER®data analysis software. Plume extents were interpreted by interpolating the log-normally transformed data, again using SURFER®, along lines of equal contaminant concentration at an appropriate established regulatory concentration . Total areas for each plume were calculated as an indicator of relative environmental damage. These plume

  11. Assessing Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

    EPA Science Inventory

    In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved PAHs and PCBs in the water column prior...

  12. Immobilization of U(VI) from Oxic Groundwater by Hanford 300 Area Sediments and Effects of Columbia River Water

    SciTech Connect

    Ahmed, B.; Cao, Bin; Mishra, Bhoopesh; Boyanov, Maxim I.; Kemner, Kenneth M.; Fredrickson, Jim K.; Beyenal, Haluk

    2012-09-23

    Regions within the U.S. Department of Energy Hanford 300 Area (300 A) site experience periodic hydrologic influences from the nearby Columbia River as a result of changing river stage, which causes changes in groundwater elevation, flow direction and water chemistry. An important question is the extent to which the mixing of Columbia River water and groundwater impacts the speciation and mobility of uranium (U). In this study, we designed experiments to mimic interactions among U, oxic groundwater or Columbia River water, and 300 A sediments in the subsurface environment of Hanford 300 A. The goals were to investigate mechanisms of: 1) U immobilization in 300 A sediments under bulk oxic conditions and 2) U remobilization from U-immobilized 300 A sediments exposed to oxic Columbia River water. Initially, 300 A sediments in column reactors were fed with U(VI)-containing oxic 1) synthetic groundwater (SGW), 2) organic-amended SGW (OA-SGW), and 3) de-ionized (DI) water to investigate U immobilization processes. After that, the sediments were exposed to oxic Columbia River water for U remobilization studies. The results reveal that U was immobilized by 300 A sediments predominantly through reduction (80-85%) when the column reactor was fed with oxic OA-SGW. However, U was immobilized by 300 A sediments through adsorption (100%) when the column reactors were fed with oxic SGW or DI water. The reduced U in the 300 A sediments fed with OA-SGW was relatively resistant to remobilization by oxic Columbia River water. Oxic Columbia River water resulted in U remobilization (~7%) through desorption, and most of the U that remained in the 300 A sediments fed with OA-SGW (~93%) was in the form of uraninite nanoparticles. These results reveal that: 1) the reductive immobilization of U through OA-SGW stimulation of indigenous 300 A sediment microorganisms may be viable in the relatively oxic Hanford 300 A subsurface environments and 2) with the intrusion of Columbia River water

  13. Sorption and Transport of Iodine Species in Sediments from the Savannah River and Hanford Sites

    SciTech Connect

    Hu, Q; Zhao, P; Moran, J; Seaman, J

    2004-05-20

    Iodine is an important element in studies of environmental protection and human health, global-scale hydrologic processes and nuclear nonproliferation. Biogeochemical cycling of iodine is complex, because iodine occurs in multiple oxidation states and as inorganic and organic species that may be hydrophilic, atmophilic, and biophilic. In this study, we focused on the sorption and transport behavior of iodine species (iodide, iodate, and 4-iodoaniline) in sediments collected at the Savannah River and Hanford Sites, where anthropogenic {sup 129}I from prior nuclear fuel processing activities poses an environmental risk. We conducted both column and batch experiments to investigate the sorption and transport behavior of iodine, and the sediments we examined exhibit a wide range in organic matter, clay mineralogy, soil pH, and texture. The results of our experiments illustrate complex behavior with various processes occurring, including iodate reduction, irreversible retention or mass loss of iodide, and rate-limited and nonlinear sorption. There was an appreciable iodate reduction to iodide, presumably mediated by the structural Fe(II) in some clay minerals; therefore, careful attention must be given to potential interconversion among species when interpreting the biogeochemical behavior of iodine in the environment. The different iodine species exhibited dramatically different sorption and transport behavior in three sediment samples collected from different depths at the Savannah River Site. This indicates that, when anthropogenic {sup 129}I is deposited on the surface at this site, the different iodine species will have different residence times as they migrate through the various sediment regimes. Our study results yielded additional insight into processes and mechanisms affecting the geochemical cycling of iodine in the environment, and provided quantitative estimates of key parameters (e.g., extent and rate of sorption) for risk assessment at these sites.

  14. Correlations Between Physical and Hydraulic Properties and Uranium Desorption in Contaminated, Intact Sediment Cores

    NASA Astrophysics Data System (ADS)

    Rockhold, M. L.; Oostrom, M.; Wietsma, T. W.; Zachara, J. M.

    2010-12-01

    An unlined disposal pond in the 300 Area of the Hanford Site received uranium-bearing liquid effluents associated with nuclear reactor fuel rod processing from 1943 to 1975. Contaminated sediments from the base and sides of the former pond were excavated and removed from the site in the early 1990s, but a uranium plume has persisted in the groundwater at concentrations exceeding the drinking water standard. The former process pond is located adjacent to the Columbia River and seasonal fluctuations in the river stage and water table provide a mechanism for resupplying residual uranium from the vadose zone to the groundwater when the lower vadose zone is periodically rewetted. Intact cores were collected from the site for measurements of physical, hydraulic, and geochemical properties. Multistep outflow experiments were also performed on the intact cores to determine permeability-saturation-capillary pressure relations. Pore water displaced during these experiments for two of the vadose zone cores was also analyzed for uranium. For a core containing finer-textured sediment classified as muddy sandy gravel, and a core containing coarser-textured sediment classified as gravel, the relative aqueous uranium concentrations increased by factors of 8.3 and 1.5, respectively, as the cores were desaturated and progressively smaller pore-size classes were drained. Aqueous concentrations of uranium in the extracted pore waters were up to 115 times higher than the current drinking water standard of 30 ppb. These results confirm that there is a continuing source of uranium in the vadose zone at the site, and are consistent with a hypothesis that the persistence of the groundwater uranium plume is also associated, in part, with rate-limited mass transfer from finer-textured sediments. The data from these and several other intact cores from the site are evaluated to explore relationships between physical and hydraulic properties and uranium desorption characteristics.

  15. Diverse anaerobic Cr(VI) tolerant bacteria from Cr(VI)-contaminated 100H site at Hanford

    NASA Astrophysics Data System (ADS)

    Chakraborty, R.; Phan, R.; Lam, S.; Leung, C.; Brodie, E. L.; Hazen, T. C.

    2007-12-01

    Hexavalent Chromium [Cr(VI)] is a widespread contaminant found in soil, sediment, and ground water. Cr(VI) is more soluble, toxic, carcinogenic, and mutagenic compared to its reduced form Cr(III). In order to stimulate microbially mediated reduction of Cr(VI), a poly-lactate compound HRC was injected into the chromium contaminated aquifers at site 100H at Hanford. Based on the results of the bacterial community composition using high-density DNA microarray analysis of 16S rRNA gene products, we recently investigated the diversity of the dominant anaerobic culturable microbial population present at this site and their role in Cr(VI) reduction. Positive enrichments set up at 30°C using specific defined anaerobic media resulted in the isolation of an iron reducing isolate strain HAF, a sulfate reducing isolate strain HBLS and a nitrate reducing isolate, strain HLN among several others. Preliminary 16S rDNA sequence analysis identifies strain HAF as Geobacter metallireducens, strain HLN as Pseudomonas stutzeri and strain HBLS as a member of Desulfovibrio species. Strain HAF isolated with acetate as the electron donor utilized propionate, glycerol and pyruvate as alternative carbon sources, and reduced metals like Mn(IV) and Cr(VI). Growth was optimal at 37°C, pH of 6.5 and 0% salinity. Strain HLN isolated with lactate as electron donor utilized acetate, glycerol and pyruvate as alternative carbon sources, and reduced metals like Mn(IV) and Cr(VI). Optimal growth was observed at 37°C, at a pH of 7.5 and 0.3% salinity. Anaerobic active washed cell suspension of strain HLN reduced almost 95 micromolar Cr(VI) within 4 hours relative to controls. Further, with 100 micromolar Cr(VI) as the sole electron acceptor, cells of strain HLN grew to cell numbers of 4.05X 107/ml over a period of 24hrs after an initial lag, demonstrating direct enzymatic Cr(VI) reduction by this species. 10mM lactate served as the sole electron donor. These results demonstrate that Cr

  16. Physical and hydraulic properties of sediments and engineered materials associated with grouted double-shell tank waste disposal at Hanford

    SciTech Connect

    Rockhold, M.L.; Fayer, M.J.; Heller, P.R.

    1993-09-01

    Numerical models are used to predict the fate of contaminants in the environment for durations of 10,000 years and more. At the Hanford Site, these models are being used to evaluate the potential health effects and environmental impacts associated with the disposal of double-shell tank waste in grouted vaults. These models require information on the properties of the earthen and manufactured materials that compose the vault system and its surroundings. This report documents the physical and hydraulic properties of the materials associated with burial of grouted double-shell tank waste at the Hanford Site.

  17. Radioactive contamination of fish, shellfish, and waterfowl exposed to Hanford effluents: Annual summaries, 1945--1972. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Hanf, R.W.; Dirkes, R.L.; Duncan, J.P.

    1992-07-01

    The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly summaries will be helpful to individuals and organizations interested in evaluating aquatic pathway information for locations impacted by Hanford operations and will be useful for planning the direction of future HEDR studies.

  18. A survey of benthic sediment contaminants in reaches of the Columbia River Estuary based on channel sedimentation characteristics

    USGS Publications Warehouse

    Counihan, Timothy D.; Waite, Ian R.; Nilsen, Elena B.; Hardiman, Jill M.; Elias, Edwin; Gelfenbaum, Guy; Zaugg, Steven D.

    2014-01-01

    While previous studies have documented contaminants in fish, sediments, water, and wildlife, few specifics are known about the spatial distribution of contaminants in the Columbia River Estuary (CRE). Our study goal was to characterize sediment contaminant detections and concentrations in reaches of the CRE that were concurrently being sampled to assess contaminants in water, invertebrates, fish, and osprey (Pandion haliaetus) eggs. Our objectives were to develop a survey design based on sedimentation characteristics and then assess whether sediment grain size, total organic carbon (TOC), and contaminant concentrations and detections varied between areas with different sedimentation characteristics. We used a sediment transport model to predict sedimentation characteristics of three 16 km river reaches in the CRE. We then compartmentalized the modeled change in bed mass after a two week simulation to define sampling strata with depositional, stable, or erosional conditions. We collected and analyzed bottom sediments to assess whether substrate composition, organic matter composition, and contaminant concentrations and detections varied among strata within and between the reaches. We observed differences in grain size fractions between strata within and between reaches. We found that the fine sediment fraction was positively correlated with TOC. Contaminant concentrations were statistically different between depositional vs. erosional strata for the industrial compounds, personal care products and polycyclic aromatic hydrocarbons class (Indus–PCP–PAH). We also observed significant differences between strata in the number of detections of Indus–PCP–PAH (depositional vs. erosional; stable vs. erosional) and for the flame retardants, polychlorinated biphenyls, and pesticides class (depositional vs. erosional, depositional vs. stable). When we estimated mean contaminant concentrations by reach, we observed higher contaminant concentrations in the furthest

  19. A survey of benthic sediment contaminants in reaches of the Columbia River Estuary based on channel sedimentation characteristics.

    PubMed

    Counihan, Timothy D; Waite, Ian R; Nilsen, Elena B; Hardiman, Jill M; Elias, Edwin; Gelfenbaum, Guy; Zaugg, Steven D

    2014-06-15

    While previous studies have documented contaminants in fish, sediments, water, and wildlife, few specifics are known about the spatial distribution of contaminants in the Columbia River Estuary (CRE). Our study goal was to characterize sediment contaminant detections and concentrations in reaches of the CRE that were concurrently being sampled to assess contaminants in water, invertebrates, fish, and osprey (Pandion haliaetus) eggs. Our objectives were to develop a survey design based on sedimentation characteristics and then assess whether sediment grain size, total organic carbon (TOC), and contaminant concentrations and detections varied between areas with different sedimentation characteristics. We used a sediment transport model to predict sedimentation characteristics of three 16km river reaches in the CRE. We then compartmentalized the modeled change in bed mass after a two week simulation to define sampling strata with depositional, stable, or erosional conditions. We collected and analyzed bottom sediments to assess whether substrate composition, organic matter composition, and contaminant concentrations and detections varied among strata within and between the reaches. We observed differences in grain size fractions between strata within and between reaches. We found that the fine sediment fraction was positively correlated with TOC. Contaminant concentrations were statistically different between depositional vs. erosional strata for the industrial compounds, personal care products and polycyclic aromatic hydrocarbons class (Indus-PCP-PAH). We also observed significant differences between strata in the number of detections of Indus-PCP-PAH (depositional vs. erosional; stable vs. erosional) and for the flame retardants, polychlorinated biphenyls, and pesticides class (depositional vs. erosional, depositional vs. stable). When we estimated mean contaminant concentrations by reach, we observed higher contaminant concentrations in the furthest downstream

  20. Development, Evaluation, and Application of Sediment Quality Targets for Assessing and Managing Contaminated Sediments in Tampa Bay, Florida

    USGS Publications Warehouse

    MacDonald, D.D.; Carr, R.S.; Eckenrod, D.; Greening, H.; Grabe, S.; Ingersoll, C.G.; Janicki, S.; Janicki, T.; Lindskoog, R.A.; Long, E.R.; Pribble, R.; Sloane, G.; Smorong, D.E.

    2004-01-01

    Tampa Bay is a large, urban estuary that is located in west central Florida. Although water quality conditions represent an important concern in this estuary, information from numerous sources indicates that sediment contamination also has the potential to adversely affect aquatic organisms, aquatic-dependent wildlife, and human health. As such, protecting relatively uncontaminated areas of the bay from contamination and reducing the amount of toxic chemicals in contaminated sediments have been identified as high-priority sediment management objectives for Tampa Bay. To address concerns related to sediment contamination in the bay, an ecosystem-based framework for assessing and managing sediment quality conditions was developed that included identification of sediment quality issues and concerns, development of ecosystem goals and objectives, selection of ecosystem health indicators, establishment of metrics and targets for key indicators, and incorporation of key indicators, metrics, and targets into watershed management plans and decision-making processes. This paper describes the process that was used to select and evaluate numerical sediment quality targets (SQTs) for assessing and managing contaminated sediments. These SQTs included measures of sediment chemistry, whole-sediment and pore-water toxicity, and benthic invertebrate community structure. In addition, the paper describes how the SQTs were used to develop site-specific concentration-response models that describe how the frequency of adverse biological effects changes with increasing concentrations of chemicals of potential concern. Finally, a key application of the SQTs for defining sediment management areas is discussed.

  1. Quantification of thorium and uranium sorption to contaminated sediments

    SciTech Connect

    Kaplan, D.I.

    2000-08-01

    Desorption tests using a sequential extraction method were used to characterize and quantify thorium and uranium sorption to contaminated wetland sediments collected from the Savannah River Site located in South Carolina. In situ distribution coefficients, or Kd values (Kd equal to Csolid/Cliquid), were determined. A problem associated with determining desorption Kd values is that it is difficult to identify Csolid, because by definition it must comprise only the fraction that is reversibly (and linearly) sorbed. A series of selective and sequential extractions was used to determine desorption Kd values. Thorium Kd values ranged from 115 to 2255 mL/g. Uranium Kd values ranged from 170 to 6493 mL/g. Compared to sorption Kd values, these desorption Kd values were appreciably greater because they captured the ``aging'' process of the radionuclides with the sediment, making the radionuclide more refractory. Compared to nonsite-specific data, these in situ Kd values improved accuracy, were more defensible, reduced uncertainty, and removed unnecessary conservatism for subsequent transport and risk calculations. Additional tests were conducted to provide geochemical information relevant for selecting appropriate remediation technologies for the contaminated site. Thorium and U were associated with labile fractions and were not concentrated with the smaller sediment particles. These findings suggest that phytoremediation or heap leaching, and not soil washing, are viable remediation approaches for this site.

  2. Hanford Tank 241-C-106: Impact of Cement Reactions on Release of Contaminants from Residual Waste

    SciTech Connect

    Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

    2006-09-01

    The CH2M HILL Hanford Group, Inc. (CH2M HILL) is producing risk/performance assessments to support the closure of single-shell tanks at the U.S. Department of Energy's Hanford Site. As part of this effort, staff at Pacific Northwest National Laboratory were asked to develop release models for contaminants of concern that are present in residual sludge remaining in tank 241-C-106 (C-106) after final retrieval of waste from the tank. Initial work to produce release models was conducted on residual tank sludge using pure water as the leaching agent. The results were reported in an earlier report. The decision has now been made to close the tanks after waste retrieval with a cementitious grout to minimize infiltration and maintain the physical integrity of the tanks. This report describes testing of the residual waste with a leaching solution that simulates the composition of water passing through the grout and contacting the residual waste at the bottom of the tank.

  3. Mycodiversity in marine sediments contaminated by heavy metals: preliminary results

    NASA Astrophysics Data System (ADS)

    Zotti, Mirca; Carbone, Cristina; Cecchi, Grazia; Consani, Sirio; Cutroneo, Laura; Di Piazza, Simone; Gabutto, Giacomo; Greco, Giuseppe; Vagge, Greta; Capello, Marco

    2016-04-01

    Fungi represent the main decomposers of woody and herbaceous substrates in the marine ecosystems. To date there is a gap in the knowledge about the global diversity and distribution of fungi in marine habitats. On the basis of their biological diversity and their role in ecosystem processes, marine fungi may be considered one of the most attractive groups of organisms in modern biotechnology, e.g. ecotoxic metal bioaccumulation. Here we report the data about the first mycological survey in the metal contaminated coastal sediments of the Gromolo Bay. The latter is located in Ligurian Sea (Eastern Liguria, Italy) and is characterized by an enrichment of heavy metals due to pollution of Gromolo Torrent by acidic processes that interest Fe-Cu sulphide mine. 24 samples of marine sediments were collected along a linear plot in front of the shoreline in July 2015. Each sample was separated into three aliquot for mineralogical, chemical analyses and fungal characterization. The sediment samples are characterised by clay fractions (illite and chlorite), minerals of ophiolitic rocks (mainly serpentine, pyroxene and plagioclase) and quartz and are enriched some chemical elements of environmental importance (such as Cu, Zn, Pb, Cd, As). For fungal characterisation the sediment samples were inoculated in Petri dishes on different culture media (Malt Extract Agar and Rose Bengal) prepared with sea water and added with antibiotics. The inoculated dishes were incubated at 20°C in the dark for 28 days. Every week fungal growth was monitored counting the number of colonies. Later, the colonies were isolated in axenic culture for further molecular analysis. The mycodiversity evaluate on the basis of Colony Forming Units (CFU) and microfungal-morphotype characterised by macro-and micro-morphology. Until now on the 72 Petri dishes inoculated 112 CFU of filamentous fungi were counted, among these about 50 morphotypes were characterized. The quantitative results show a mean value of 4

  4. Developmental toxicity of lead-contaminated sediment to mallard ducklings

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

    2000-01-01

    Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 ug/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

  5. Developmental toxicity of lead contaminated sediment to mallard ducks

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

    2000-01-01

    Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 I?g/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

  6. Passive sampling methods for contaminated sediments: State of the science for organic contaminants

    PubMed Central

    Lydy, Michael J; Landrum, Peter F; Oen, Amy MP; Allinson, Mayumi; Smedes, Foppe; Harwood, Amanda D; Li, Huizhen; Maruya, Keith A; Liu, Jingfu

    2014-01-01

    This manuscript surveys the literature on passive sampler methods (PSMs) used in contaminated sediments to assess the chemical activity of organic contaminants. The chemical activity in turn dictates the reactivity and bioavailability of contaminants in sediment. Approaches to measure specific binding of compounds to sediment components, for example, amorphous carbon or specific types of reduced carbon, and the associated partition coefficients are difficult to determine, particularly for native sediment. Thus, the development of PSMs that represent the chemical activity of complex compound–sediment interactions, expressed as the freely dissolved contaminant concentration in porewater (Cfree), offer a better proxy for endpoints of concern, such as reactivity, bioaccumulation, and toxicity. Passive sampling methods have estimated Cfree using both kinetic and equilibrium operating modes and used various polymers as the sorbing phase, for example, polydimethylsiloxane, polyethylene, and polyoxymethylene in various configurations, such as sheets, coated fibers, or vials containing thin films. These PSMs have been applied in laboratory exposures and field deployments covering a variety of spatial and temporal scales. A wide range of calibration conditions exist in the literature to estimate Cfree, but consensus values have not been established. The most critical criteria are the partition coefficient between water and the polymer phase and the equilibrium status of the sampler. In addition, the PSM must not appreciably deplete Cfree in the porewater. Some of the future challenges include establishing a standard approach for PSM measurements, correcting for nonequilibrium conditions, establishing guidance for selection and implementation of PSMs, and translating and applying data collected by PSMs. Integr Environ Assess Manag 2014;10:167–178. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of

  7. Sorption and transport of iodine species in sediments from the Savannah River and Hanford Sites.

    PubMed

    Hu, Qinhong; Zhao, Pihong; Moran, Jean E; Seaman, John C

    2005-07-01

    Iodine is an important element in studies of environmental protection and human health, global-scale hydrologic processes and nuclear nonproliferation. Biogeochemical cycling of iodine is complex, because iodine occurs in multiple oxidation states and as inorganic and organic species that may be hydrophilic, atmophilic, and biophilic. In this study, we applied new analytical techniques to study the sorption and transport behavior of iodine species (iodide, iodate, and 4-iodoaniline) in sediments collected at the Savannah River and Hanford Sites, where anthropogenic (129)I from prior nuclear fuel processing activities poses an environmental risk. We conducted integrated column and batch experiments to investigate the interconversion, sorption and transport of iodine species, and the sediments we examined exhibit a wide range in organic matter, clay mineralogy, soil pH, and texture. The results of our experiments illustrate complex behavior with various processes occurring, including iodate reduction, irreversible retention or mass loss of iodide, and rate-limited and nonlinear sorption. There was an appreciable iodate reduction to iodide, presumably mediated by the structural Fe(II) in some clay minerals; therefore, careful attention must be given to potential interconversion among species when interpreting the biogeochemical behavior of iodine in the environment. The different iodine species exhibited dramatically different sorption and transport behavior in three sediment samples, possessing different physico-chemical properties, collected from different depths at the Savannah River Site. Our study yielded additional insight into processes and mechanisms affecting the geochemical cycling of iodine in the environment, and provided quantitative estimates of key parameters (e.g., extent and rate of sorption) for risk assessment at these sites.

  8. Bioavailability Assessment of a Contaminated Field Sediment from Patrick Bayou, Texas, USA: Toxicity Identification Evaluation and Equilibrium Partitioning

    EPA Science Inventory

    Contaminated sediments are commonly found in urbanized harbors. At sufficiently high contaminant levels, sediments can cause toxicity to aquatic organisms and impair benthic communities. As a result, remediation is necessary and diagnosing the cause of sediment toxicity become...

  9. Rate of mercury loss from contaminated estuarine sediments

    USGS Publications Warehouse

    Bothner, Michael H.; Jahnke, R.A.; Peterson, M.L.; Carpenter, R.

    1980-01-01

    The concentration of mercury in contaminated estuarine sediments of Bellingham Bay, Washington was found to decrease with a half-time of about 1.3 yr after the primary anthropogenic source of mercury was removed. In situ measurements of the mercury flux from sediments, in both dissolved and volatile forms, could not account for this decrease. This result suggests that the removal of mercury is associated with sediment particles transported out of the study area. This decrease was modeled using a steady-state mixing model. Mercury concentrations in anoxic interstitial waters reached 3.5 ??g/l, 126 times higher than observed in the overlying seawater. Mercury fluxes from these sediments ranged from 1.2 to 2.8 ?? 10-5 ng/cm2/sec, all in a soluble form. In general, higher Hg fluxes were associated with low oxygen or reducing conditions in the overlying seawater. In contrast, no flux was measurable from oxidizing interstitial water having mercury concentrations of 0.01-0.06 ??/l. ?? 1980.

  10. Environmental monitoring of Columbia River sediments: Grain-size distribution and contaminant association

    SciTech Connect

    Blanton, M.L.; Gardiner, W.W.; Dirkes, R.L.

    1995-04-01

    Based on the results of this study and literature review, the following conclusions can be made: Sediment grain size and TOC (total organic carbon) influence contaminant fate and transport (in general, sediments with higher TOC content and finer grain-size distribution can have higher contaminant burdens than sediments from a given river section that have less TOC and greater amounts of coarse-grained sediments). Physiochemical sediment characteristics are highly variable among monitoring sites along the Columbia River. Sediment grain characterization and TOC analysis should be included in interpretations of sediment-monitoring data.

  11. TXRF analysis of soils and sediments to assess environmental contamination.

    PubMed

    Bilo, Fabjola; Borgese, Laura; Cazzago, Davide; Zacco, Annalisa; Bontempi, Elza; Guarneri, Rita; Bernardello, Marco; Attuati, Silvia; Lazo, Pranvera; Depero, Laura E

    2014-12-01

    Total reflection x-ray fluorescence spectroscopy (TXRF) is proposed for the elemental chemical analysis of crustal environmental samples, such as sediments and soils. A comparative study of TXRF with respect to flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy was performed. Microwave acid digestion and suspension preparation methods are evaluated. A good agreement was found among the results obtained with different spectroscopic techniques and sample preparation methods for Cr, Mn, Fe, Ni, Cu, and Zn. We demonstrated that TXRF is suitable for the assessment of environmental contamination phenomena, even if the errors for Pb, As, V, and Ba are ingent.

  12. Groundwater contaminant plume maps and volumes, 100-K and 100-N Areas, Hanford Site, Washington

    USGS Publications Warehouse

    Johnson, Kenneth H.

    2016-09-27

    This study provides an independent estimate of the areal and volumetric extent of groundwater contaminant plumes which are affected by waste disposal in the 100-K and 100-N Areas (study area) along the Columbia River Corridor of the Hanford Site. The Hanford Natural Resource Trustee Council requested that the U.S. Geological Survey perform this interpolation to assess the accuracy of delineations previously conducted by the U.S. Department of Energy and its contractors, in order to assure that the Natural Resource Damage Assessment could rely on these analyses. This study is based on previously existing chemical (or radionuclide) sampling and analysis data downloaded from publicly available Hanford Site Internet sources, geostatistically selected and interpreted as representative of current (from 2009 through part of 2012) but average conditions for groundwater contamination in the study area. The study is limited in scope to five contaminants—hexavalent chromium, tritium, nitrate, strontium-90, and carbon-14, all detected at concentrations greater than regulatory limits in the past.All recent analytical concentrations (or activities) for each contaminant, adjusted for radioactive decay, non-detections, and co-located wells, were converted to log-normal distributions and these transformed values were averaged for each well location. The log-normally linearized well averages were spatially interpolated on a 50 × 50-meter (m) grid extending across the combined 100-N and 100-K Areas study area but limited to avoid unrepresentative extrapolation, using the minimum curvature geostatistical interpolation method provided by SURFER®data analysis software. Plume extents were interpreted by interpolating the log-normally transformed data, again using SURFER®, along lines of equal contaminant concentration at an appropriate established regulatory concentration . Total areas for each plume were calculated as an indicator of relative environmental damage. These plume

  13. ORGANIC CONTAMINANT DISTRIBUTION IN SEDIMENTS, POLYCHAETES (NEREIS VIRENS) AND THE AMERICAN LOBSTER, HOMARUS AMERICANUS IN A LABORATORY FOOD CHAIN EXPERIMENT

    EPA Science Inventory

    A laboratory experiment was conducted to investigate the transfer of organic contaminants from an environmentally contaminated marine sediment through a simple marine food chain. The infaunal polychaete, Nereis virens, was exposed to contaminated sediment collected from the Passa...

  14. Field evidence for strong chemical separation of contaminants inthe Hanford Vadose Zone

    SciTech Connect

    Conrad, Mark E.; DePaolo, Donald J.; Maher, Katharine; Gee,Glendon W.; Ward, Anderson L.

    2007-04-10

    Water and chemical transport from a point source withinvadose zone sediments at Hanford were examined with a leak testconsisting of five 3800-liter aliquots of water released at 4.5 m depthevery week over a 4-week period. The third aliquot contained bromide, D2Oand 87Sr. Movement of the tracers was monitored for 9 months by measuringpore water compositions of samples from boreholes drilled 2-8 m from theinjection point. Graded sedimentary layers acting as natural capillarybarriers caused significant lateral spreading of the leak water. D2Oconcentrations>50 percent of the concentration in the tracer aliquotwere detected at 9-11 m depth. However, increased water contents, lowerd18O values, and geophysical monitoring of moisture changes at otherdepths signified high concentrations of leak fluids were added where D2Oconcentrations were<3 percent above background, suggesting limitedmixing between different aliquots of the leak fluids. Initially highbromide concentrations decreased more rapidly over time than D2O,suggesting enhanced transport of bromide due to anion exclusion. Nosignificant increase in 87Sr was detected in the sampled pore water,indicating strong retardation of Sr by the sediments. These resultshighlight some of the processes strongly affecting chemical transport inthe vadose zone and demonstrate the significant separation of contaminantplumes that can occur.

  15. Accumulation of radionuclides in bed sediments of the Columbia River between Hanford reactors and McNary Dam

    USGS Publications Warehouse

    Nelson, Jack L.; Haushild, W.L.

    1970-01-01

    Amounts of radionuclides from the Hanford reactors contained in bed sediments of the Columbia River were estimated by two methods: (1) from data on radionuclide concentration for the bed sediments between the reactors and McNary Dam, and (2) from data on radionuclide discharge for river stations at Pasco, Washington, and Umatilla, Oregon. Umatilla is 3.2 kilometers below McNary Dam. Accumulations of radionuclides in the Pasco to Umatilla reach estimated by the two methods agree within about 8%. In October 1965 approximately 16,000 curies of gamma emitting radionuclides were resident in bed sediments of the river between the Hanford reactors and McNary Dam. Concentrations and accumulations of chromium-51, zinc-65, cobalt-60, manganese-54, and scandium-46 generally are much higher near McNary Dam than they are in the vicinity of the reactors. These changes are caused by an increase downstream from the reactors in the proportion of the bed sediment that is fine grained and the proportions of the transported zinc, cobalt, manganese, and scandium radionuclides associated with sediment particles.

  16. Monitoring and modeling contaminated sediment transport in the White Oak Creek watershed

    SciTech Connect

    Fontaine, T.A.

    1991-11-01

    Over the past 47 years, operations and waste disposal activities at Oak Ridge National Laboratory have resulted in the contamination of the White Oak Creek drainage system. The containments presenting the highest risk to human health and the environment are particle reactive and are associated with the soils and sediments in White Oak Creek. During floods, the erosion of these sediments results in the transport of contaminants out of the catchment into the Clinch River. A long-term strategy is required to monitor the movement of contaminated sediments and to predict the transport of these sediments that could occur during major floods. A monitoring program will provide the information required to (1) evaluate the existing off-site transport of contaminated sediments, (2) evaluate the need for short-term control measures, (3) set priorities for remediation of contaminated areas in White Oak Creek (4) verify the success of completed remedial actions intended to control the movement of contaminated sediments, and (5) develop a computer model to simulate the transport of contaminated sediments in White Oak Creek. A contaminant-transport model will be developed to (1) evaluate the potential for the off-site transport of contaminated sediments during major floods, (2) develop long term control measures and remediation solutions, (3) predict the impact of future land-use changes in White Oak Creek on the transport of contaminated sediment. This report contains a plan for the monitoring and modeling activities required to accomplish these objectives.

  17. Assessing organic contaminant fluxes from contaminated sediments following dam removal in an urbanized river.

    PubMed

    Cantwell, Mark G; Perron, Monique M; Sullivan, Julia C; Katz, David R; Burgess, Robert M; King, John

    2014-08-01

    In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the water column prior to and following removal of a small, low-head dam in the Pawtuxet River, an urbanized river located in Cranston, RI, USA. During the study, concentrations of particulate and dissolved PAHs ranged from 21.5 to 103 μg/g and from 68 to 164 ng/L, respectively. Overall, temporal trends of PAHs showed no increases in either dissolved or particulate phases following removal of the dam. Dissolved concentrations of PCBs were very low, remaining below 1.72 ng/L at all sites. Particulate PCB concentrations across sites and time showed slightly greater variability, ranging from 80 to 469 ng/g, but with no indication that dam removal influenced any increases. Particulate PAHs and PCBs were sampled continuously at the site located below the dam and did not show sustained increases in concentration resulting from dam removal. The employment of passive sampling technology and sediment traps was highly effective in monitoring the concentrations and flux of contaminants moving through the river system. Variations in river flow had no effect on the concentration of contaminants in the dissolved or particulate phases, but did influence the flux rate of contaminants exiting the river. Overall, dam removal did not cause measurable sediment disturbance or increase the concentration or fluxes of dissolved or particulate PAHs and PCBs. This is due in large part to low volumes of impounded sediment residing above the dam and highly armored sediments in the river channel, which limited erosion. Results from this study will be used to improve methods and approaches that assess the short- and long-term impacts ecological restoration activities such as

  18. Dynamic modeling of contaminant transport with surface runoff and sediment

    SciTech Connect

    Ashraf, M.S.

    1992-01-01

    Non-point source pollution in surface runoff due to agricultural activities presents one of the principal problems in the U.S. Solution to the problem of delivering pollutants is crucial to a non-point abatement program. Mathematical models can serve as tools to relate hydrologic conditions and soil properties to the processes of pollutant transport, and can be used to evaluate the effectiveness of best management practices in reducing non-point source pollutant load in surface waters. In this study, a dynamic model component is developed to simulate transport of non-point source pollutants, mostly agricultural chemicals, with surface runoff and sediment in agricultural watersheds. Algorithms are developed to route chemicals and infiltrating water through different soil increments assuming complete mixing until time of ponding or initiation of runoff. Once runoff starts, the runoff interacts with a mixing soil layer in a non-uniform fashion and exchange of chemicals takes place between runoff and the mixing soil layer. When runoff storage builds up, it is assumed that a relatively stagnant depth of runoff interacts with the mixing soil layer. This stagnant depth is obtained by applying boundary layer theory. Mass balance equations are used to route chemicals associated with runoff and sediment along the slope lengths for overland and channel flow. Model algorithms are coupled with the hydrologic and sediment transport model RUNOFF to simulate transport of contaminants with surface runoff and sediments in agricultural watersheds. The model performance is evaluated with data ranging from controlled laboratory experiments to watershed scale. The concept of non-uniform mixing is tested with a laboratory data set found in the literature. A total of fifteen runs are made, five for each of the chemicals, nitrate, phosphate, and cyanazine. The model results show good agreements with the observed yields of runoff, sediment, orthophosphate, and ammonium.

  19. DISTRIBUTION OF ORGANIC WASTEWATER CONTAMINANTS BETWEEN WATER AND SEDIMENT IN SURFACE WATERS OF THE UNITED STATES

    EPA Science Inventory

    Trace concentrations of pharmaceuticals and other organic wastewater contaminants have been determined in the surface waters of Europe and the United States. A preliminary report of substantially higher concentrations of pharmaceuticals in sediment suggests that bottom sediment ...

  20. ISSUES IN ASSESSING LOW LEVEL IONIZABLE CONTAMINANT PARTITIONING IN SOILS AND SEDIMENTS

    EPA Science Inventory

    Solubilization has profound implications for such diverse risk assessment activities as assessing sediment contaminant porewater exposures to benthic fauna, determining half lives of refractory toxicants in natural soils and sediments, and assessing the fate and transport of th...

  1. Uranium fate in Hanford sediment altered by simulated acid waste solutions

    DOE PAGES

    Gartman, Brandy N.; Qafoku, Nikolla P.; Szecsody, James E.; Kukkadapu, Ravi K.; Wang, Zheming; Wellman, Dawn M.; Truex, Michael J.

    2015-07-31

    Many aspects of U(VI) behavior in sediments that are previously exposed to acidic waste fluids for sufficiently long times to induce significant changes in pH and other physical, mineralogical and chemical properties, are not well documented in the literature. For this reason, we conducted a series of macroscopic batch experiments combined with a variety of bulk characterization studies (Mössbauer and laser spectroscopy), micro-scale inspections (µ-XRF), and molecular scale interrogations (XANES) with the objectives to: i) determine the extent of U(VI) partitioning to Hanford sediments previously exposed to acidic waste simulants (pH = 2 and pH = 5) and under neutralmore » conditions (pH = 8) at varying background solution concentrations (i.e., NaNO3); ii) determine micron-scale solid phase associated U valence state and phase identity; and iii) provide information for a plausible conceptual model of U(VI) attenuation under waste plume acidic conditions. The results of the batch experiments showed that the acid pre-treated sediment had high affinity for aqueous U(VI), which was removed from solution via two pH dependent and apparently different mechanisms (adsorption at pH = 2 and precipitation at pH = 5). The micro-scale inspections and XANES analyses confirmed that high concentration areas were rich mainly in U(VI), demonstrating that most of the added U(VI) was not reduced to U(IV). The laser spectroscopy data showed that uranyl phosphates {e.g. metaautunite [Ca(UO2)2(PO4)2•10-12H2O] and phosphuranylite [KCa(H3O)3(UO2)7(PO4)4O4•8(H2O)]} were present in the sediments. They also showed clear differences between the U bearing phases in the experiments conducted in the presence or absence of air. As a result, the data generated from these experiments will help in a better understanding of the reactions and processes that have a significant effect and/or control U mobility.« less

  2. Uranium fate in Hanford sediment altered by simulated acid waste solutions

    SciTech Connect

    Gartman, Brandy N.; Qafoku, Nikolla P.; Szecsody, James E.; Kukkadapu, Ravi K.; Wang, Zheming; Wellman, Dawn M.; Truex, Michael J.

    2015-07-31

    Many aspects of U(VI) behavior in sediments that are previously exposed to acidic waste fluids for sufficiently long times to induce significant changes in pH and other physical, mineralogical and chemical properties, are not well documented in the literature. For this reason, we conducted a series of macroscopic batch experiments combined with a variety of bulk characterization studies (Mössbauer and laser spectroscopy), micro-scale inspections (µ-XRF), and molecular scale interrogations (XANES) with the objectives to: i) determine the extent of U(VI) partitioning to Hanford sediments previously exposed to acidic waste simulants (pH = 2 and pH = 5) and under neutral conditions (pH = 8) at varying background solution concentrations (i.e., NaNO3); ii) determine micron-scale solid phase associated U valence state and phase identity; and iii) provide information for a plausible conceptual model of U(VI) attenuation under waste plume acidic conditions. The results of the batch experiments showed that the acid pre-treated sediment had high affinity for aqueous U(VI), which was removed from solution via two pH dependent and apparently different mechanisms (adsorption at pH = 2 and precipitation at pH = 5). The micro-scale inspections and XANES analyses confirmed that high concentration areas were rich mainly in U(VI), demonstrating that most of the added U(VI) was not reduced to U(IV). The laser spectroscopy data showed that uranyl phosphates {e.g. metaautunite [Ca(UO2)2(PO4)2•10-12H2O] and phosphuranylite [KCa(H3O)3(UO2)7(PO4)4O4•8(H2O)]} were present in the sediments. They also showed clear differences between the U bearing phases in the experiments conducted in the presence or absence of air. As a result, the data generated from these experiments will help in a better understanding of the reactions and

  3. Establishing the environmental risk of metal contaminated river bank sediments

    NASA Astrophysics Data System (ADS)

    Lynch, Sarah; Batty, Lesley; Byrne, Patrick

    2016-04-01

    Climate change predictions indicate an increase in the frequency and duration of flood events along with longer dry antecedent conditions, which could alter patterns of trace metal release from contaminated river bank sediments. This study took a laboratory mesocosm approach. Chemical analysis of water and sediment samples allowed the patterns of Pb and Zn release and key mechanisms controlling Pb and Zn mobility to be determined. Trace metal contaminants Pb and Zn were released throughout flooded periods. The highest concentrations of dissolved Pb were observed at the end of the longest flood period and high concentrations of dissolved Zn were released at the start of a flood. These concentrations were found to exceed environmental quality standards. Key mechanisms controlling mobility were (i) evaporation, precipitation and dissolution of Zn sulphate salts, (ii) anglesite solubility control of dissolved Pb, (iii) oxidation of galena and sphalerite, (iv) reductive dissolution of Mn/Fe hydroxides and co-precipitation/adsorption with Zn. In light of climate change predictions these results indicate future scenarios may include larger or more frequent transient 'pulses' of dissolved Pb and Zn released to river systems. These short lived pollution episodes could act as a significant barrier to achieving the EU Water Framework Directive objectives.

  4. Spectroscopic evidence for uranium bearing precipitates in vadose zone sediments at the Hanford 300-area site

    USGS Publications Warehouse

    Arai, Y.; Marcus, M.A.; Tamura, N.; Davis, J.A.; Zachara, J.M.

    2007-01-01

    Uranium (U) solid-state speciation in vadose zone sediments collected beneath the former North Process Pond (NPP) in the 300 Area of the Hanford site (Washington) was investigated using multi-scale techniques. In 30 day batch experiments, only a small fraction of total U (???7.4%) was released to artificial groundwater solutions equilibrated with 1% pCO2. Synchrotron-based micro-X-ray fluorescence spectroscopy analyses showed that U was distributed among at least two types of species: (i) U discrete grains associated with Cu and (ii) areas with intermediate U concentrations on grains and grain coatings. Metatorbernite (Cu[UO2]2[PO 4]2??8H2O) and uranophane (Ca[UO 2]2[SiO3(OH)]2?? 5H 2O) at some U discrete grains, and muscovite at U intermediate concentration areas, were identified in synchrotron-based micro-X-ray diffraction. Scanning electron microscopy/energy dispersive X-ray analyses revealed 8-10 ??m size metatorbernite particles that were embedded in C-, Al-, and Si-rich coatings on quartz and albite grains. In ??- and bulk-X-ray absorption structure (??-XAS and XAS) spectroscopy analyses, the structure of metatorbernite with additional U-C and U-U coordination environments was consistently observed at U discrete grains with high U concentrations. The consistency of the ??- and bulk-XAS analyses suggests that metatorbernite may comprise a significant fraction of the total U in the sample. The entrapped, micrometer-sized metatorbernite particles in C-, Al-, and Si-rich coatings, along with the more soluble precipitated uranyl carbonates and uranophane, likely control the long-term release of U to water associated with the vadose zone sediments. ?? 2007 American Chemical Society.

  5. Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes

    NASA Astrophysics Data System (ADS)

    Crandell, L. E.; Peters, C. A.; Um, W.; Jones, K. W.; Lindquist, W. B.

    2012-04-01

    At the former nuclear weapon production site in Hanford, WA, caustic radioactive tank waste leaks into subsurface sediments and causes dissolution of quartz and aluminosilicate minerals, and precipitation of sodalite and cancrinite. This work examines changes in pore structure due to these reactions in a previously-conducted column experiment. The column was sectioned and 2D images of the pore space were generated using backscattered electron microscopy and energy dispersive X-ray spectroscopy. A pre-precipitation scenario was created by digitally removing mineral matter identified as secondary precipitates. Porosity, determined by segmenting the images to distinguish pore space from mineral matter, was up to 0.11 less after reaction. Erosion-dilation analysis was used to compute pore and throat size distributions. Images with precipitation had more small and fewer large pores. Precipitation decreased throat sizes and the abundance of large throats. These findings agree with previous findings based on 3D X-ray CMT imaging, observing decreased porosity, clogging of small throats, and little change in large throats. However, 2D imaging found an increase in small pores, mainly in intragranular regions or below the resolution of the 3D images. Also, an increase in large pores observed via 3D imaging was not observed in the 2D analysis. Changes in flow conducting throats that are the key permeability-controlling features were observed in both methods.

  6. Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes.

    PubMed

    Crandell, L E; Peters, C A; Um, W; Jones, K W; Lindquist, W B

    2012-04-01

    At the former nuclear weapon production site in Hanford, WA, caustic radioactive tank waste leaks into subsurface sediments and causes dissolution of quartz and aluminosilicate minerals, and precipitation of sodalite and cancrinite. This work examines changes in pore structure due to these reactions in a previously-conducted column experiment. The column was sectioned and 2D images of the pore space were generated using backscattered electron microscopy and energy dispersive X-ray spectroscopy. A pre-precipitation scenario was created by digitally removing mineral matter identified as secondary precipitates. Porosity, determined by segmenting the images to distinguish pore space from mineral matter, was up to 0.11 less after reaction. Erosion-dilation analysis was used to compute pore and throat size distributions. Images with precipitation had more small and fewer large pores. Precipitation decreased throat sizes and the abundance of large throats. These findings agree with previous findings based on 3D X-ray CMT imaging, observing decreased porosity, clogging of small throats, and little change in large throats. However, 2D imaging found an increase in small pores, mainly in intragranular regions or below the resolution of the 3D images. Also, an increase in large pores observed via 3D imaging was not observed in the 2D analysis. Changes in flow conducting throats that are the key permeability-controlling features were observed in both methods. PMID:22360994

  7. Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes.

    PubMed

    Crandell, L E; Peters, C A; Um, W; Jones, K W; Lindquist, W B

    2012-04-01

    At the former nuclear weapon production site in Hanford, WA, caustic radioactive tank waste leaks into subsurface sediments and causes dissolution of quartz and aluminosilicate minerals, and precipitation of sodalite and cancrinite. This work examines changes in pore structure due to these reactions in a previously-conducted column experiment. The column was sectioned and 2D images of the pore space were generated using backscattered electron microscopy and energy dispersive X-ray spectroscopy. A pre-precipitation scenario was created by digitally removing mineral matter identified as secondary precipitates. Porosity, determined by segmenting the images to distinguish pore space from mineral matter, was up to 0.11 less after reaction. Erosion-dilation analysis was used to compute pore and throat size distributions. Images with precipitation had more small and fewer large pores. Precipitation decreased throat sizes and the abundance of large throats. These findings agree with previous findings based on 3D X-ray CMT imaging, observing decreased porosity, clogging of small throats, and little change in large throats. However, 2D imaging found an increase in small pores, mainly in intragranular regions or below the resolution of the 3D images. Also, an increase in large pores observed via 3D imaging was not observed in the 2D analysis. Changes in flow conducting throats that are the key permeability-controlling features were observed in both methods.

  8. Bioavailability of sediment-associated mercury to Hexagenia mayflies in a contaminated floodplain river

    USGS Publications Warehouse

    Naimo, T.J.; Wiener, J.G.; Cope, W.G.; Bloom, N.S.

    2000-01-01

    We examined the bioavailability of mercury in sediments from the contaminated Sudbury River (Massachusetts, U.S.A.). Mayfly nymphs (Hexagenia) were exposed in four 21-day bioaccumulation tests to contaminated and reference sediments (treatments) from reservoirs, flowing reaches, palustrine wetlands, and a riverine lake. Mean total mercury (Sigma Hg) ranged from 880 to 22 059 ng.g dry weight(-1) in contaminated sediments and from 90 to 272 ng.g(-1) in reference sediments. Mean final concentrations of methyl mercury (MeHg) in test water were greatest (8-47 ng Hg.L-1) in treatments with contaminated wetland sediments, which had mean Sigma Hg ranging from 1200 to 2562 ng.g(-1). In mayflies, final mean concentrations of MeHg were highest in treatments with contaminated wetland sediments (122-183 ng Hg.g(-1)), intermediate in treatments with contaminated sediments from reservoirs, flowing reaches, and a riverine lake (75-127 ng Hg.g(-1)), and lowest in treatments with reference sediments (32-41 ng Hg.g(-1)). We conclude that the potential entry of MeHg into the benthic food chain was greater in contaminated palustrine wetlands than in the contaminated reservoirs, which had the most contaminated sediments.

  9. 70193-Influence of Clastic Dikes on Vertical Migration of Contaminants in the Vadose Zonde at Hanford

    SciTech Connect

    Christopher J Murray; Anderson L. Ward; John L. Wilson

    2004-04-07

    that depend on input flux rates and boundary type and that may sometimes mask the underlying heterogeneity. The networks occupy two complementary states: a high-permeability region in the fine-textured media at low fluxes and a high-permeability region in the coarse-textured media at high fluxes. Transition between the two states occurred at an input flux of about 100 mm yr{sup -1}. At this input flux, preferential channels essentially disappear with the dike and host matrix conducting at similar rates. This suggests that clastic dikes might serve as a conduit for more rapid movement of moisture and mobile contaminants to the water table, but only under a restricted set of recharge (or leak) conditions. However, owing to the relatively high content of reactive minerals, especially clay, that is found in the clastic dikes, the movement of reactive contaminants like heavy metals and radionuclides may be restricted. The field site developed for this project, as well as the data and numerical models, are now the focus of several ongoing studies funded by the Hanford Groundwater Protection Program's Science and Technology (S&T) Project. These studies focus on collecting datasets to support conceptual model development and model calibration, the development and use of advanced scaling methods to facilitate inverse modeling of heterogeneous systems, and the identification of appropriate parameters for predictive modeling of field-scale reactive transport.

  10. Remediation of contaminated soils and sediments using Daramend bioremediation

    SciTech Connect

    Burwell, S.W.; Bucens, P.G.; Seech, A.G.

    1996-05-01

    Soils and sediments containing polyaromatic hydrocarbons (PAH), petroleum hydrocarbons, heavy oils, chlorinated phenols, pesticides, herbicides and phthalates, either individually or in combination, have been difficult to remediate in the past. Not only the species of contaminant, but contaminant concentrations were roadblocks to successful use of bioremediation. Daramend{sup Tm} remediation has removed many of these obstacles through extensive research. Bench-scale, pilot-scale and full-scale demonstrations have been conducted at a variety of industrial sites. At a manufactured gas site, 295 days of Daramend remediation reduced concentrations of chrysene and fluoranthene from 38.9 mg/kg to 5.9 mg/kg and 84.6 mg/kg to 7.8 mg/kg respectively. Elsewhere, the total PAH concentration in a silty soil was reduced from 1,442 mg/kg to 36 mg/kg. Concentrations of even the most refractory PAHs (e.g. pyrene, benzo(a)pyrene) were reduced to below the established clean-up guidelines. Total petroleum hydrocarbons (diesel fuel) have also been reduced from 8,700 mg/kg to 34 mg/kg after 182 days of treatment. Similarly, in a clay soil contaminated by crude oil processing, the concentrations of high molecular weight aliphatic hydrocarbons were rapidly reduced (138 days) to below the remediation criteria. Demonstrations with wood treatment site soils have proven Daramend remediation effective in enhancing the target compound degradation rates. Soils containing 2170 mg PCP/kg were shown to contain only 11 mg PCP/kg after 280 days of Darmend remediation. The issue of toxicity of soil containing increased amounts of pentachlorophenols was solved. Performance data collected during these projects indicate that Daramend remediation provides a cost effective method for clean-up of soils and sediments containing a variety of organic compounds.

  11. Cluster analysis of contaminated sediment data: nodal analysis.

    PubMed

    Hartwell, S Ian; Claflin, Larry W

    2005-07-01

    The objective of the present study was to explore the use of multivariate statistical methods as a means to discern relationships between contaminants and biological and/or toxicological effects in a representative data set from the National Status and Trends (NS&T) Program. Data from the National Oceanic and Atmospheric Administration, NS&T Program's Bioeffects Survey of Delaware Bay, USA, were examined using various univariate and multivariate statistical techniques, including cluster analysis. Each approach identified consistent patterns and relationships between the three types of triad data. The analyses also identified factors that bias the interpretation of the data, primarily the presence of rare and unique species and the dependence of species distributions on physical parameters. Sites and species were clustered with the unweighted pair-group method using arithmetic averages clustering with the Jaccard coefficient that clustered species and sites into mutually consistent groupings. Pearson product moment correlation coefficients, normalized for salinity, also were clustered. The most informative analysis, termed nodal analysis, was the intersection of species cluster analysis with site cluster analysis. This technique produced a visual representation of species association patterns among site clusters. Site characteristics, such as salinity and grain size, not contaminant concentrations, appeared to be the primary factors determining species distributions. This suggests the sediment-quality triad needs to use physical parameters as a distinct leg from chemical concentrations to improve sediment-quality assessments in large bodies of water. Because the Delaware Bay system has confounded gradients of contaminants and physical parameters, analyses were repeated with data from northern Chesapeake Bay, USA, with similar results. PMID:16050601

  12. EXTRACTION OF ORGANIC CONTAMINANTS FROM MARINE SEDIMENTS AND TISSUES USING MICROWAVE ENERGY

    EPA Science Inventory

    In this study, we compared microwave solvent extraction (MSE) to conventional methods for extracting organic contaminants from marine sediments and tissues with high and varying moisture content. The organic contaminants measured were polychlorinated biphenyl (PCB) congeners, chl...

  13. Sediment toxicity, contamination and amphipod abundance at a DDT- and dieldrin-contaminated site in San Francisco Bay

    SciTech Connect

    Swartz, R.C.; Cole, F.A.; Lamberson, J.O.; Ferraro, S.P.; Schults, D.W.

    1994-01-01

    Sediment toxicity to the amphipod Eohaustorius estuarius, sediment contamination, and the abundance of amphipods were examined along a contamination gradient in the Lauritzen Channel and adjacent parts of Richmond Harbor, California. Dieldrin and DDT were formulated and ground at this site from 1945 to 1966. Sediment contamination by both dieldrin and the sum of DDT and its metabolites (DDT's) was positively correlated with sediment toxicity and negatively correlated with the abundance of amphipods excluding Grandidierella japonica. The maximum dieldrin and DDT's concentrations in toxic units were 0.018 and 9.43, respectively, indicating that DDT's was the dominant ecotoxicological factor. Concentrations of PAHs, PCBs, and metals were not sufficient to cause appreciable toxicity, except at one PAH-contaminated station. Relations between DDT's, sediment toxicity, and amphipod abundance are similar at three DDT's-contaminated sites. The 10-d LC50 for DDT's in field-collected sediment was 2,500 micrograms/gram organic carbon (OC) for Eohaustorius estuarius in the study, 1,040 micrograms/gram OC for Rhepoxynius abronius exposed to Palos Verdes Shelf, California, sediment, and 2,580 micrograms/gram OC for Hyalella azteca exposed to sediment from a freshwater stream system near Huntsville, Alabama. The threshold for 10-d sediment toxicity occurred at about 300 micrograms DDT's/gram OC. The abundance of amphipods (except Grandidierella japonica) was reduced at DDT's concentrations >100 micrograms/gram OC. Correlations between toxicity, contamination, and biology indicate that acute sediment toxicity to Eohaustorius estuarius, Rhopoxynius abronius, or Hyalella azteca in lab tests provides reliable evidence of biologically adverse sediment contamination in the field.

  14. Ecotoxicological study of arsenic and lead contaminated soils in former orchards at the Hanford Site, USA.

    PubMed

    Delistraty, Damon; Yokel, Jerry

    2014-01-01

    The purpose of this study was to assess ecotoxicity of former orchard soils contaminated with lead arsenate pesticides at the Hanford Site in Washington state (USA). Surface soil, plant, and invertebrate samples were collected from 11 sites in former orchard areas. Mean (standard deviation [SD]) for As and Pb in soil were 39.5 (40.6) and 208 (142) mg/kg dry wt, respectively (n = 11). These concentrations exceeded Hanford background levels but were similar to orchard soils elsewhere. In our study, As and Pb soil concentrations were positively and significantly correlated (r = 0.87, Bonferroni P < 0.05). Speciation of total inorganic As in soil (n = 6) demonstrated that As+5 was the dominant form (>99%). Mean (SD) for As and Pb in cheatgrass were 3.9 (7.9) and 12.4 (20.0) mg/kg dry wt, respectively (n = 11), while mean (SD) for As and Pb in darkling beetles were 5.4 (2.6) and 3.9 (3.0) mg/kg dry wt, respectively (n = 8). Linear regressions were constructed to estimate soil to cheatgrass and soil to darkling beetle uptake for As and Pb. These were significant (Bonferroni P < 0.05) only for cheatgrass versus soil (As) and darkling beetle versus soil (Pb). Standardized lettuce seedling and earthworm bioassays were performed with a subset of soil samples (n = 6). No significant effects (P > 0.05) were observed in lettuce survival or growth nor in earthworm survival or sublethal effects. Based on these bioassays, unbounded no observed effect concentrations (NOECs) in soil for As and Pb were 128 and 390 mg/kg dry wt, respectively. However, our range of soil concentrations generally overlapped a set of ecotoxicological benchmarks reported in the literature. Given uncertainty and limited sampling related to our NOECs, as well as uncertainty in generic benchmarks from the literature, further study is needed to refine characterization of As and Pb ecotoxicity in former orchard soils at the Hanford Site.

  15. Historical records of radioactive contamination in biota at the 200 Areas of the Hanford Site

    SciTech Connect

    Johnson, A.R.; Markes, B.M.; Schmidt, J.W.; Shah, A.N.; Weiss, S.G.; Wilson, K.J.

    1994-06-01

    This document summarizes and reports a literature search of 85 environmental monitoring records of wildlife and vegetation (biota) at the 200 East Area and the 200 West Area of the Hanford Site since 1965. These records were published annually and provided the majority of the data in this report. Additional sources of data have included records of specific facilities, such as site characterization documents and preoperational environmental surveys. These documents have been released for public use. Records before 1965 were still being researched and therefore not included in this document. The intent of compiling these data into a single source was to identify past and current concentrations of radionuclides in biota at specific facilities and waste sites within each operable unit that may be used to help guide cleanup activities in the 200 Areas to be completed under the Comprehensive Environmental Response and Liability Act (CERCLA). The 200 East Area and 200 West Area were the locations of the Hanford Site separation and process facilities and waste management units. For the purposes of this document, a sample was of interest if a Geiger-Mueller counter equipped with a pancake probe-indicated beta/gamma emitting radioactivity above 200 counts per minute (cpm), or if laboratory radioanalyses indicated a radionuclide concentration equaled or exceeded 10 picocuries per gram (pCi/g). About 4,500 individual cases of monitoring for radionuclide uptake or transport in biota in the 200 Areas environs were included in the documents reviewed. About 1,900 (i.e., 42%) of these biota had radionuclide concentrations in excess of 10 pCi/g. These radionuclide transport or uptake cases were distributed among 45 species of wildlife (primarily small mammals and feces) and 30 species of vegetation. The wildlife species most commonly associated with radioactive contamination were the house mouse and the deer mouse and of vegetation species, the Russian thistle.

  16. Biogeochemical Processes In Ethanol Stimulated Uranium Contaminated Subsurface Sediments

    SciTech Connect

    Mohanty, Santosh R.; Kollah, Bharati; Hedrick, David B.; Peacock, Aaron D.; Kukkadapu, Ravi K.; Roden, Eric E.

    2008-06-15

    A laboratory incubation experiment was conducted with uranium contaminated subsurface sediment to assess the geochemical and microbial community response to ethanol amendment. A classical sequence of TEAPs was observed in ethanol-amended slurries, with NO3- reduction, Fe(III) reduction, SO4 2- reduction, and CH4 production proceeding in sequence until all of the added 13C-ethanol (9 mM) was consumed. Approximately 60% of the U(VI) content of the sediment was reduced during the period of Fe(III) reduction. No additional U(VI) reduction took place during the sulfate-reducing and methanogenic phases of the experiment. Only gradual reduction of NO3 -, and no reduction of U(VI), took place in ethanol-free slurries. Stimulation of additional Fe(III) or SO4 2- reduction in the ethanol-amended slurries failed to promote further U(VI) reduction. Reverse transcribed 16S rRNA clone libraries revealed major increases in the abundance of organisms related to Dechloromonas, Geobacter, and Oxalobacter in the ethanolamended slurries. PLFAs indicative of Geobacter showed a distinct increase in the amended slurries, and analysis of PLFA 13C/12C ratios confirmed the incorporation of ethanol into these PLFAs. A increase in the abundance of 13C-labeled PLFAs indicative of Desulfobacter, Desulfotomaculum, and Desulfovibrio took place during the brief period of sulfate reduction which followed the Fe(III) reduction phase. Our results show that major redox processes in ethanol-amended sediments can be reliably interpreted in terms of standard conceptual models of TEAPs in sediments. However, the redox speciation of uranium is complex and cannot be explained based on simplified thermodynamic considerations.

  17. Sorption of radioactive contaminants by sediment from the Kara Sea

    SciTech Connect

    Fuhrmann, M.; Zhou, H.; Neiheisel, J.; Dyer, R.

    1995-02-01

    The purpose of this study is to quantify some of the parameters needed to perform near-field modeling of sites in the Kara Sea that were impacted by the disposal of radioactive waste. The parameters of interest are: the distribution coefficients (K{sub d}) for several important radionuclides, the mineralogy of the sediment, and the relationship of K{sub d} to liquid to solid ratio. Sediment from the Kara Sea (location: 73{degrees} 00` N, 58{degrees} 00` E) was sampled from a depth of 287 meters on August 23/24, 1992, during a joint Russian/Norwegian scientific cruise. Analysis of the material included mineralogy, grain size and total organic carbon. Uptake kinetics were determined for {sup 85}Sr, {sup 99}Tc, {sup 125}I, {sup 137}Cs, {sup 210}Pb, {sup 232}U, and {sup 241}Am and distribution coefficients (K{sub d}) were determined for these radionuclides using batch type experiments. Sorption isotherms were developed for {sup 85}Sr, {sup 99}Tc, and {sup 137}Cs to examine the effect that varying the concentration of a tracer has on the quantity of that tracer taken up by the solid. The effect of liquid to solid ratio on the uptake of contaminants was determined for {sup 99}Tc and {sup 137}Cs. In another set of experiments, the sediment was separated into four size fractions and uptake was determined for each fraction for {sup 85}Sr, {sup 99}Tc, and {sup 137}Cs. In addition, the sediment was analyzed to determine if it contains observable concentrations of anthropogenic radionuclides.

  18. Contaminated sediments database for Long Island Sound and the New York Bight

    USGS Publications Warehouse

    Mecray, Ellen L.; Reid, Jamey M.; Hastings, Mary E.; Buchholtz ten Brink, Marilyn R.

    2003-01-01

    The Contaminated Sediments Database for Long Island Sound and the New York Bight provides a compilation of published and unpublished sediment texture and contaminant data. This report provides maps of several of the contaminants in the database as well as references and a section on using the data to assess the environmental status of these coastal areas. The database contains information collected between 1956-1997; providing an historical foundation for future contaminant studies in the region.

  19. INNOVATIVE IN-SITU REMEDIATION OF CONTAMINATED SEDIMENTS FOR SIMULTANEOUS CONTROL OF CONTAMINATION AND EROSION

    SciTech Connect

    Knox, A; Michael Paller, M; Danny D. Reible, D; Ioana G. Petrisor, I

    2007-11-28

    New technologies are needed that neutralize contaminant toxicity and control physical transport mechanisms that mobilize sediment contaminants. The last 12 months of this comprehensive project investigated the use of combinations of sequestering agents to develop in situ active sediment caps that stabilize mixtures of contaminants and act as a barrier to mechanical disturbance under a broad range of environmental conditions. Efforts focused on the selection of effective sequestering agents for use in active caps, the composition of active caps, and the effects of active cap components on contaminant bioavailability and retention. Results from this project showed that phosphate amendments, some organoclays, and the biopolymer, chitosan, were very effective at removing metals from both fresh and salt water. These amendments also exhibited high retention (80% or more) of most metals indicating reduced potential for remobilization to the water column. Experiments on metal speciation and retention in contaminated sediment showed that apatite and organoclay can immobilize a broad range of metals under both reduced and oxidized conditions. These studies were followed by sequential extractions to evaluate the bioavailability and retention of metals in treated sediments. Metal fractions recovered in early extraction steps are more likely to be bioavailable and were termed the Potentially Mobile Fraction (PMF). Less bioavailable fractions collected in later extraction steps were termed the Recalcitrant Factor (RF). Apatite and organoclay reduced the PMF and increased the RF for several elements, especially Pb, Zn, Ni, Cr, and Cd. Empirically determined partitioning coefficients and modeling studies were used to assess the retention of organic contaminants on selected sequestering agents. Organoclays exhibited exceptionally high sorption of polycyclic aromatic hydrocarbons as indicated by a comparison of K{sub d} values among 12 amendments. These results suggested that

  20. Pertechnetate (TcO4-) reduction by reactive ferrous iron forms in naturally anoxic, redox transition zone sediments from the Hanford Site, USA

    SciTech Connect

    Peretyazhko, Tetyana; Zachara, John M.; Kukkadapu, Ravi K.; Heald, Steve M.; Kutnyakov, Igor V.; Resch, Charles T.; Arey, Bruce W.; Wang, Chong M.; Kovarik, Libor; Phillips, Jerry L.; Moore, Dean A.

    2012-09-01

    Technetium is an important environmental contaminant introduced by the processing and disposal of irradiated nuclear fuel and atmospheric nuclear tests. Under oxic conditions technetium is soluble and exists as pertechnatate anion (TcO4-), while under anoxic conditions Tc is usually insoluble and exists as precipitated Tc(IV). Here we investigated abiotic Tc(VII) reduction in mineralogically heterogeneous, Fe(II)-containing sediments. The sediments were collected from a 55 m borehole that sampled a semi-confined aquifer at the Hanford Site, USA that contained a dramatic redox transition zone. One oxic facies (18.0-18.3 m) and five anoxic facies (18.3-18.6 m, 30.8-31.1 m, 39.0-39.3 m, 47.2-47.5 m and 51.5-51.8 m) were selected for this study. Chemical extractions, X-ray diffraction, electron microscopy, and Mössbauer spectroscopy were applied to characterize the Fe(II) mineral suite that included: Fe(II)-phyllosilicates, pyrite, magnetite and siderite. The Fe(II) mineral phase distribution differed between the sediments. Sediment suspensions were adjusted to the same 0.5 M HCl extracted Fe(II) concentration (0.6 mM) for Tc(VII) reduction experiments. Aqueous Fe was low in all sediment suspensions (<2 μM) and below the Fe(II)aq detection limit (10 μM). Technetium(VII) reduction occurred in all anoxic sediments at depths greater than 18.3 m and reaction time differed significantly between the sediments (8-219 d). Mössbauer analysis of the Tc-reacted, 30.8-31.1 m sediment confirmed that Tc(VII) was reduced by solid-phase Fe(II), with siderite and Fe(II)-containing phyllosilicates implicated as redox reactive phases. Technetium-XAS analysis demonstrated that Tc associated with sediments was in the Tc(IV) valence state and immobilized as clusters of a TcO2·nH2O-like phase. The speciation of redox product Tc(IV) was not affected by reduction rate or Fe(II) mineralogy.

  1. AN EVALUATION OF HANFORD SITE TANK FARM SUBSURFACE CONTAMINATION FY2007

    SciTech Connect

    MANN, F.M.

    2007-07-10

    The Tank Farm Vadose Zone (TFVZ) Project conducts activities to characterize and analyze the long-term environmental and human health impacts from tank waste releases to the vadose zone. The project also implements interim measures to mitigate impacts, and plans the remediation of waste releases from tank farms and associated facilities. The scope of this document is to report data needs that are important to estimating long-term human health and environmental risks. The scope does not include technologies needed to remediate contaminated soils and facilities, technologies needed to close tank farms, or management and regulatory decisions that will impact remediation and closure. This document is an update of ''A Summary and Evaluation of Hanford Site Tank Farm Subsurface Contamination''. That 1998 document summarized knowledge of subsurface contamination beneath the tank farms at the time. It included a preliminary conceptual model for migration of tank wastes through the vadose zone and an assessment of data and analysis gaps needed to update the conceptual model. This document provides a status of the data and analysis gaps previously defined and discussion of the gaps and needs that currently exist to support the stated mission of the TFVZ Project. The first data-gaps document provided the basis for TFVZ Project activities over the previous eight years. Fourteen of the nineteen knowledge gaps identified in the previous document have been investigated to the point that the project defines the current status as acceptable. In the process of filling these gaps, significant accomplishments were made in field work and characterization, laboratory investigations, modeling, and implementation of interim measures. The current data gaps are organized in groups that reflect Components of the tank farm vadose zone conceptual model: inventory, release, recharge, geohydrology, geochemistry, and modeling. The inventory and release components address residual wastes that will

  2. MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS

    SciTech Connect

    Beyenal, Haluk; McLEan, Jeff; Majors, Paul; Fredrickson, Jim

    2013-11-14

    The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.

  3. Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

    PubMed

    Edge, Katelyn J; Dafforn, Katherine A; Simpson, Stuart L; Ringwood, Amy H; Johnston, Emma L

    2015-06-01

    Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS). To date, few studies have experimentally compared the contributions to biological stress of contaminated and clean suspended solids. The authors mixed field-collected sediments (<63 μm) from clean and contaminated field sites to create 4 treatments of increasing metal concentrations. Sydney rock oysters were then exposed to sediment treatments at different TSS concentrations for 4 d, and cellular biomarkers (lysosomal membrane stability, lipid peroxidation, and glutathione) were measured to evaluate sublethal toxicity. Lysosomal membrane stability was the most sensitive biomarker for distinguishing effects from resuspended contaminated sediments, as increasing amounts of contaminated TSS increased lysosomal membrane destabilization. The authors' results illustrate the importance of considering contaminant exposures from resuspended sediments when assessing the toxicity of contaminants to aquatic organisms.

  4. The effect of contaminant desorption on assimilation of sediment-sorbed hydrophobic contaminants by deposit-feeders

    SciTech Connect

    Brownawell, B.; Lamoureux, E.; McElroy, A.; Lopez, G.; Ahrens, M.

    1995-12-31

    The literature shows that assimilation efficiencies of lab-spiked nonpolar contaminants by deposit-feeders are generally much greater than the assimilation of the organic carbon sorbent matrix. Thus the rate and extent of contaminant desorption into the aqueous gut environment is likely to play a significant role in uptake from sediments. Contaminated New York Harbor sediments were examined in parallel desorption kinetic and bioaccumulation studies with the clam Yoldia limatula. A clear relationship was observed between the contaminant desorption rates over the first two days and organism/sediment bioaccumulation factors (BAF) determined across a wide range of individual PCBs, PAHs, and linear alkylbenzenes. Bioavailability was affected by hydrophobicity, shape of the contaminant, and contaminant class/source. Lower bioavailability of PAH may be the result of matrix associations with soot or fine coal particles. Interestingly, contaminant desorption/bioavailability were not influenced greatly by depth in the sediment core. The authors have initiated a study to determine the critical chemical and biological factors that control contaminant assimilation. They hope that it will become possible to replace expensive biological exposure studies with simple desorption tests when assessing the risk associated with contaminated sediments or dredge materials.

  5. Impact Assessment of Existing Vadose Zone Contamination at the Hanford Site SX Tank Farm

    SciTech Connect

    Khaleel, Raziuddin; White, Mark D.; Oostrom, Martinus; Wood, Marcus I.; Mann, Frederick M.; Kristofzski, John G.

    2007-11-01

    The USDOE has initiated an impact assessment of existing vadose zone contamination at the Hanford Site SX tank farm in southeastern Washington State. The assessment followed the Resource Conservation and Recovery Act (RCRA) Corrective Action process to address the impacts of past tank waste releases to the vadose zone at the single-shell tank farm. Numerical models were developed that consider the extent of contamination presently within the vadose zone and predict contaminant movement through the vadose zone to groundwater. The transport of representative mobile (technetium-99) and immobile (cesium-137) constituents was evaluated in modeling. The model considered the accelerated movement of moisture around and beneath single-shell tanks that is attributed to bare, gravel surfaces resulting from the construction of the underground storage tanks. Infiltration, possibly nearing 100 mm yr–1, is further amplified in the tank farm because of the umbrella effect created by percolating moisture being diverted by the impermeable, sloping surface of the large, 24-m-diameter, buried tank domes. For both the base case (no-action alternative) simulation and a simulation that considered placement of an interim surface barrier to minimize infiltration, predicted groundwater concentrations for technetium-99 at the SX tank farm boundary were exceedingly high, on the order of 106 pCi L–1. The predicted concentrations are, however, somewhat conservative because of our use of two-dimensional modeling for a three-dimensional problem. A series of simulations were performed, using recharge rates of 50, 30, and 10 mm yr–1, and compared to the base case (100 mm yr–1) results. As expected, lowering meteoric recharge delayed peak arrival times and reduced peak concentrations at the tank farm boundary.

  6. IMPACT ASSESSMENT OF EXISTING VADOSE ZONE CONTAMINATION AT THE HANFORD SITE SX TANK FARM

    SciTech Connect

    KHALEEL R

    2007-11-01

    The USDOE has initiated an impact assessment of existing vadose zone contamination at the Hanford Site SX tank farm in southeastern Washington State. The assessment followed the Resource Conservation and Recovery Act (RCRA) Corrective Action process to address the impacts of past tank waste releases to the vadose zone at the single-shell tank farm. Numerical models were developed that consider the extent of contamination presently within the vadose zone and predict contaminant movement through the vadose zone to groundwater. The transport of representative mobile (technetium-99) and immobile (cesium-137) constituents was evaluated in modeling. The model considered the accelerated movement of moisture around and beneath single-shell tanks that is attributed to bare, gravel surfaces resulting from the construction of the underground storage tanks. Infiltration, possibly nearing 100 mm yr{sup -1}, is further amplified in the tank farm because of the umbrella effect created by percolating moisture being diverted by the impermeable, sloping surface of the large, 24-m-diameter, buried tank domes. For both the base case (no-action alternative) simulation and a simulation that considered placement of an interim surface barrier to minimize infiltration, predicted, groundwater concentrations for technetium-99 at the SX tank farm boundary were exceedingly high, on the order of 10{sup 6} pCi L{sup -1}. The predicted concentrations are, however, somewhat conservative because of our use of two-dimensional modeling for a three-dimensional problem. A series of simulations were performed, using recharge rates of 50, 30, and 10 mm yr{sup -1}, and compared to the basecase(100 mm yr{sup -1}) results. As expected, lowering meteoric recharge delayed peak arrival times and reduced peak concentrations at the tank farm boundary.

  7. Heavy Metals Contamination in Coastal Sediments of Karachi, Pakistan

    NASA Astrophysics Data System (ADS)

    Siddique, A.; Mumtaz, M.; Zaigham, N. A.; Mallick, K. A.; Saied, S.; Khwaja, H. A.

    2008-12-01

    Toxic compounds such as heavy metals exert chronic and lethal effects in animals, plants, and human health. With the rapid industrialization, urbanization, and economic development in Karachi, heavy metals are continuing to be introduced to estuarine and coastal environment through rivers, runoff and land-based point sources. Pollution in the Karachi coastal region (167 km long) is mainly attributed to Lyari and Malir Rivers flowing through the city of Karachi. Both rivers are served by various channels of domestic and industrial wastes carrying more than 300 million gallons per day untreated effluent of 6000 industries and ultimately drain into the beaches of Arabian Sea. Concentrations of selected heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surface sediments from eighty-eight sites in Karachi coastal region were studied in order to understand metal contamination due to industrialization, urbanization, and economic development in Karachi. Sediment samples were collected in 2005 and 2006. We have found that heavy metal concentrations in surface sediments varied from 0.006 to 24.3 ug/g for Cd, 5.1 to 95 ug/g for Co, 2.9 to 571 ug/g for Cr, 6.9 to 272 ug/g for Cu, 0.55 to 6.5% for Fe, 1.2 to 318 ug/g for Mn, 7.5 to 75 ug/g for Ni, 6.3 to 121 ug/g for Pb, and 3.3 to 389 ug/g for Zn. Enrichment factors (EFs) were calculated to assess whether the concentrations observed represent background or contaminated levels. The highest levels of metals were found to be at the confluence of the Lyari and Malir River streams at the Arabian Sea, indicating the impact of the effluents of the highly urbanized and industrialized city of Karachi. Furthermore, this study assessed heavy metal toxicity risk with the application of Sediment Quality Guideline (SQG) indices (effect range low/effect range median values, ERL/ERM). Results indicated that the potential toxicity of marine environment can cause adverse biological effects to the biota directly and the human health

  8. Metal-contaminated Sediment Effects on Biofilm Communities: Impairment of Multiple Stream Ecosystem Functions

    NASA Astrophysics Data System (ADS)

    Burton, G.; Costello, D.

    2012-12-01

    Photosynthetic biofilms are crucial drivers of many important stream ecosystem functions (e.g., primary and secondary production, N cycling), yet we have a limited understanding of how these critical communities respond to contaminated sediments. Divalent metals (e.g., Cu, Ni, Zn) are ubiquitous in urban streams and may be contributing to the decline in ecosystem function in urban waters. We exposed natural biofilm communities in five different streams to a common sediment amended with four concentrations of Ni and Cu. Contaminated sediments were placed into cups, covered with mesh disks for biofilm attachment, and secured to the streambed. After 6 weeks, biofilm-colonized disks were analyzed for net primary production (NPP), chlorophyll a, and metal content. Sediments below the biofilms were analyzed for total metals, acid volatile sulfide, and high-resolution vertical dissolved oxygen concentrations. Additional biofilm disks were separated from the sediment and fed to Lymnaea stagnalis to assess indirect effects of sediment metal on grazers. Among our five streams, we found variation in the biofilm response to metals with the most productive stream (Elm Creek) showing the strongest negative response to metal-contaminated sediment. Contaminated sediments in Elm Creek reduced biofilm growth, slowed primary production, and prevented penetration of oxygen into surface sediments. In the less productive streams, biofilms did not reduce NPP in the presence of sediment metal and there was still substantial penetration of oxygen into sediments; however, metals moved out of the sediment and accumulated in the biofilm. L. stagnalis exposed to metal-contaminated biofilms fed at a slower rate than those given clean biofilms. This study suggests that biofilms, and the biogeochemical cycles they drive, can potentially be impaired by contaminated sediment but the response is context dependent. Further, indirect dietary effects of contaminated sediment occur more widely than

  9. Relative role of pore water versus ingested sediment in bioavailability of organic contaminants in marine sediments

    SciTech Connect

    Forbes, T.L.; Hansen, R.; Kure, L.K.; Forbes, V.E.; Giessing, A. |

    1998-12-01

    Experimental data for fluoranthene and feeding selectivity in combination with reaction-diffusion modeling suggest that ingestion of contaminated sediment may often be the dominant uptake pathway for deposit-feeding invertebrates in sediments. A dietary absorption efficiency of 56% and accompanying forage ratio of 2.4 were measured using natural sediment that had been dual-labeled ({sup 14}C:{sup 51}Cr) with fluoranthene and fed to the marine deposit-feeding polychaete Capitella species I. Only 3 to 4% of the total absorption could be accounted for by desorption during gut passage. These data were then used as input into a reaction-diffusion model to calculate the importance of uptake from ingested sediment relative to pore-water exposure. The calculations predict a fluoranthene dietary uptake flux that is 20 to 30 times greater than that due to pore water. Factors that act to modify or control the formation of local chemical gradients, boundary layers, or dietary absorption rates including particle selection or burrow construction will be important in determining the relative importance of potential exposure pathways. From a chemical perspective, the kinetics of the adsorption and desorption process are especially important as they will strongly influence the boundary layer immediately surrounding burrowing animals or irrigated tubes. The most important biological factors likely include irrigation behavior and burrow density and size.

  10. Heavy metal contamination of sediments in the upper connecting channels of the Great Lakes

    USGS Publications Warehouse

    Nichols, S. Jerrine; Manny, Bruce A.; Schloesser, Donald W.; Edsall, Thomas A.

    1991-01-01

    In 1985, sampling at 250 stations throughout the St. Marys, St. Clair, and Detroit rivers and Lake St. Clair — the connecting channels of the upper Great Lakes — revealed widespread metal contamination of the sediments. Concentrations of cadmium, chromium, copper, lead, mercury, nickel, and zinc each exceeded U.S. Environmental Protection Agency sediment pollution guidelines at one or more stations throughout the study area. Sediments were polluted more frequently by copper, nickel, zinc, and lead than by cadmium, chromium, or mercury. Sediments with the highest concentrations of metals were found (in descending order) in the Detroit River, the St. Marys River, the St. Clair River, and Lake St. Clair. Although metal contamination of sediments was most common and sediment concentrations of metals were generally highest near industrial areas, substantial contamination of sediments by metals was present in sediment deposition areas up to 60 km from any known source of pollution.

  11. Assessment and Remediation of Contaminated Sediments (ARCS) program. Estimating contaminant losses from components of remediation alternatives for contaminated sediments. Report for March 1991-April 1994

    SciTech Connect

    Myers, T.E.; Averette, D.E.; Olin, T.J.; Palermo, M.R.; Reible, D.D.

    1996-03-01

    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. 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).

  12. The mechanisms of contaminants release due to incipient motion at sediment-water interface

    NASA Astrophysics Data System (ADS)

    Zhu, HongWei; Cheng, PengDa; Zhong, BaoChang; Wang, DaoZeng

    2014-08-01

    Sediments in many rivers and lakes are subjected to resuspension due to a combination of hydrodynamics. However, the roles of contaminant-contained dissolved and particulate sediments during the resuspension release are rarely studied. This study focuses on the release quantity of contaminants in both water phase and solid phase. Conservative tracer (NaCl) and reactive tracer (Phosphorus) were respectively added to cohesive fine-grained sediments and non-cohesive coarse-grained sediments. A range of typical shear stress was conducted to characterize the time-depended release of contaminants in a laboratory flume. When the sediment started to move, the concentration of contaminant in the overlying water increased with the bed shear stress, but the dissolved contaminants responded faster than the particulate ones. The observed contaminant release process can be divided into three main stages: the initial two hours fast mixing: the release contribution of pore water could reach up to 75%; the middle 4-6 h adsorption: the partitioning coefficient of contaminant between water phase and solid phase decreased over the time, and the adsorption of contaminates from resuspended sediment dominated the negative release; the last equilibrium stage: the desorption and adsorption reached equilibrium, and the reactive contaminant made an impact on the water quality in the solid phase. The existing formulas to evaluate the release flux are far from practice meaning as the sediment contaminants undergo a very complex release process.

  13. Microscale Controls on the Fate of Contaminant Uranium in the Vadose Zone, Hanford Site, Washington

    SciTech Connect

    McKinley, James P.; Zachara, John M.; Liu, Chongxuan; Heald, Steve M.; Prenitzer, Brenda I.; Kempshall, Brian

    2006-04-15

    An alkaline brine containing uranyl (UO22+) leaked to the thick unsaturated zone at the Hanford Site. X-ray and electron microprobe imaging showed that the uranium was associated with a minority of clasts, specifically granitic clasts occupying less than four percent of the sediment volume. XANES analysis at micron resolution showed the uranium to be hexavalent. The uranium was precipitated in microfractures as radiating clusters of uranyl silicates, and sorbed uranium was not observed on other surfaces. Compositional determinations of the 1-3 µm precipitates were difficult, but indicated a sodium potassium uranyl silicate, likely sodium boltwoodite. Observations suggested that uranyl was removed from pore waters by diffusion and precipitation in microfractures, where dissolved silica within the granite-equilibrated solution would cause supersaturation with respect to sodium boltwoodite. This hypothesis was tested using a diffusion reaction model operating at microscale. Conditions favoring precipitation were simulated to be transient, and driven by the compositional contrast between pore and fracture space. Pore-space conditions, including alkaline pH, were eventually imposed on the microfracture environment. However, conditions favoring precipitation were prolonged within the microfracture by reaction at the silicate mineral surface to buffer pH in a solubility limiting acidic state, and to replenish dissolved silica. During this time, uranyl was additionally removed to the fracture space by diffusion from pore space. Uranyl is effectively immobilized within the microfracture environment within the presently unsaturated vadose zone.

  14. Bioleaching of multiple metals from contaminated sediment by moderate thermophiles.

    PubMed

    Gan, Min; Jie, Shiqi; Li, Mingming; Zhu, Jianyu; Liu, Xinxing

    2015-08-15

    A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability.

  15. Sediment testing intermittent renewal system for the automated renewal of overlying water in toxicity tests with contaminated sediments

    SciTech Connect

    Benoit, D.A.; Phipps, G.L.; Ankley, G.T.

    1993-01-01

    A sediment testing intermittent renewal (STIR) system (stationary or portable) for invertebrate toxicity testing with contaminated sediments has been successfully developed and thoroughly tested at ERL-Duluth. Both the stationary and portable systems enable the maintenance of acceptable water quality (e.g. DO) through the capability of automatically renewing overlying water in sediment tests at rates ranging from 1 to 21 volume renewals/day. The STIR system not only significantly reduces the labor associated with renewal of overlying water but also affords a gentle exchange of water that results in virtually no sediment resuspension. Both systems can also be installed in a compact vented enclosure to permit safe testing of hazardous contaminated sediments. To date the STIR system has been used extensively for conducting 10-day bulk sediment tests with Chironomus tentans, Hyalella azteca and Lumbriculus variegatus.

  16. Equilibrium Partitioning Approach for Assessing Toxicity of Contaminants in Sediments: Linking Measured Concentrations to Effects

    EPA Science Inventory

    A variety of approaches exist for assessing the degree, extent and/or risk of metals contamination in sediments. Selection of the “correct” approach depends on the nature of the question being asked (e.g., the degree of metals contamination in marine sediments may be estimated by...

  17. EVALUATION OF THE STATE-OF-THE-ART CONTAMINATED SEDIMENT TRANSPORT AND FATE MODELING SYSTEM

    EPA Science Inventory

    Modeling approaches for evaluating the transport and fate of sediment and associated contaminants are briefly reviewed. The main emphasis is on: 1) the application of EFDC (Environmental Fluid Dynamics Code), the state-of-the-art contaminated sediment transport and fate public do...

  18. Chemical contamination and physical characteristics of sediments in the upper Great Lakes connecting channels 1985

    USGS Publications Warehouse

    Bertram, Paul E.; Edsall, Thomas A.; Manny, Bruce A.; Nichols, Susan J.; Schloesser, Donald W.

    1991-01-01

    Contamination of sediments by toxic organic substances and heavy metals was widespread throughout the connecting channels of the upper Great Lakes in 1985. Sediments at 250 stations in the connecting channels were analyzed for total PCBs, oil and grease, phenols, total cyanide, total volatile solids, mercury, cadmium, chromium, cobalt, copper, lead, nickel, and zinc, and the results were evaluated according to U.S. EPA guidelines for polluted sediments. Sediments were most heavily contaminated near industrialized areas, although some areas more than 40 km downstream from known point sources of pollution were moderately contaminated by oil and metals.

  19. Elevated sulfate reduction in metal-contaminated freshwater lake sediments

    SciTech Connect

    Gough, H.L.; Dahl, A.L.; Tribou, E.; Noble, P.A.; Gaillard, J.-F.; Stahl, D.A.

    2009-01-06

    Although sulfate-reducing prokaryotes have long been studied as agents of metals bioremediation, impacts of long-term metals exposure on biologically mediated sulfur cycling in natural systems remains poorly understood. The effects of long-term exposure to metal stress on the freshwater sulfur cycle were studied, with a focus on biologic sulfate reduction using a combination of microbial and chemical methods. To examine the effects after decades of adaptation time, a field-based experiment was conducted using multiple study sites in a natural system historically impacted by a nearby zinc smelter (Lake DePue, Illinois). Rates were highest at the most metals-contaminated sites (-35 {mu}mol/cm{sup 3}/day) and decreased with decreased pore water zinc and arsenic contamination levels, while other environmental characteristics (i.e., pH, nutrient concentrations and physical properties) showed little between-site variation. Correlations were established using an artificial neural network to evaluate potentially non-linear relationships between sulfate reduction rates (SRR) and measured environmental variables. SRR in Lake DePue were up to 50 times higher than rates previously reported for lake sediments and the chemical speciation of Zn was dominated by the presence of ZnS as shown by X-ray Absorption Spectroscopy (XAS). These results suggest that long-term metal stress of natural systems might alter the biogeochemical cycling of sulfur by contributing to higher rates of sulfate reduction.

  20. SEDIMENT TOXICITY AS AN INDICATOR OF CONTAMINANT STRESS IN EMAP-ESTUARIES

    EPA Science Inventory

    Toxicity of sediments is widely used in EPA, ACOE, and NOAA monitoring and regulatory programs as a complement to measuring of chemical concentrations as it provides an indication of the bioavailability of sediment contaminants. Sediment toxicity was included as an abiotic condit...

  1. A TOXICITY ASSESSMENT APPROACH TO EVALUATING IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Freshwater and marine sediment toxicity tests were used to measure baseline toxicity of sediment samples collected from New Jersey/New York Harbor (NJ/NY) (non-PAH- contaminated) sediment (ERC). Four freshwater toxicity tests were used: 1) amphipod (Hyalella azteca) mortality and...

  2. Evaluation of the Reference Envelope Approach for Assessing Toxicity in Contaminated Surficial Urban Freshwater Sediments

    EPA Science Inventory

    The reference envelope (RE) has been proposed as an alternative approach to assess sediment toxicity to overcome limitations imposed by the use of control sediments including differences in non-contaminant characteristics and low statistical power when many test sediments are com...

  3. A TOXICITY ASSESSMENT APPROACH FOR THE EVALUATION OF IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Freshwater and marine sediment toxicity test were used to measure baseline toxicity of sediment samples collected from New York/New Jersey Harbor (NY/NJH) and East River (ER) (PAH contaminated) sediments and to determine the effectiveness of the developed biotreatment strategies ...

  4. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans (journal version)

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-01-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund-site soils on freshwater invertebrates. These two species were used successfully in acute sediment tests and were shown to be useful in chronic tests in water.

  5. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-10-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund site soils on freshwater invertebrates. These two species have been used successfully in acute sediment tests, and have been shown to be useful in chronic tests in water--only bioassays.

  6. Hanford waste-form release and sediment interaction: A status report with rationale and recommendations for additional studies

    SciTech Connect

    Serne, R.J. ); Wood, M.I. )

    1990-05-01

    This report documents the currently available geochemical data base for release and retardation for actual Hanford Site materials (wastes and/or sediments). The report also recommends specific laboratory tests and presents the rationale for the recommendations. The purpose of this document is threefold: to summarize currently available information, to provide a strategy for generating additional data, and to provide recommendations on specific data collection methods and tests matrices. This report outlines a data collection approach that relies on feedback from performance analyses to ascertain when adequate data have been collected. The data collection scheme emphasizes laboratory testing based on empiricism. 196 refs., 4 figs., 36 tabs.

  7. Contaminant and genotoxicity profiles of sediments and zebra mussels as indicators of chemical contamination in Hamilton Harbour

    SciTech Connect

    McCarry, B.E.; Allan, L.M.; Marvin, C.H.; Villella, J.; Bryant, D.W.

    1995-12-31

    Samples of bottom sediments, suspended sediments and Zebra mussels were collected from Hamilton Harbour, an embayment of western Lake Ontario. In addition, sediment samples were collected from creeks which flow into the Harbour. These sediment samples were extracted with dichloromethane and the organic extract was cleaned up prior to analysis for PAH and thia-arenes by GC-MS. These extracts were also subjected to genotoxicity bioassays (Ames assays) in two strains of Salmonella typhimurium (a TA98-like strain, YG1024-S9 and a TA100-like strain, YG1025 + S9). The sediment and Zebra mussels samples collected near sites of heavy coal tar contamination showed PAH, thia-arene and genotoxicity profiles that are very similar to the corresponding profiles for coal tar. These observations are consistent with the resuspension and distribution of coal tar-contaminated bottom sediments in the water column. The sediment samples collected in a major creek entering the Harbor and the sediment and Zebra mussels samples collected in Windemere Arm near the mouth of this creek showed very different chemical and genotoxicity profiles. Thus, the chemical and genotoxicity burdens on Hamilton Harbour posed by the resuspension of coal tar-contaminated sediments and the inputs from urban activity into a major creek and the Harbor can be differentiated.

  8. Effect of biostimulation on the microbial community in PCB-contaminated sediments through periodic amendment of sediment with iron.

    PubMed

    Srinivasa Varadhan, A; Khodadoust, Amid P; Brenner, Richard C

    2011-10-01

    Reductive dehalogenation of polychlorinated biphenyls (PCBs) by indigenous dehalorespiring microorganisms in contaminated sediments may be enhanced via biostimulation by supplying hydrogen generated through the anaerobic corrosion of elemental iron added to the sediment. In this study, the effect of periodic amendment of sediment with various dosages of iron on the microbial community present in sediment was investigated using phospholipid fatty acid analysis (PLFA) over a period of 18 months. Three PCB-contaminated sediments (two freshwater lake sediments and one marine sediment) were used. Signature biomarker analysis of the microbial community present in all three sediments revealed the enrichment of Dehalococcoides species, the population of which was sustained for a longer period of time when the sediment microcosms were amended with the lower dosage of iron (0.01 g iron per g dry sediment) every 6 months as compared to the blank system (without iron). Lower microbial stress levels were reported for the system periodically amended with 0.01 g of iron per g dry sediment every 6 months, thus reducing the competition from other hydrogen-utilizing microorganisms like methanogens, iron reducers, and sulfate reducers. The concentration of hydrogen in the system was found to be an important factor influencing the shift in microbial communities in all sediments with time. Periodic amendment of sediment with larger dosages of iron every 3 months resulted in the early prevalence of Geobacteraceae and sulfate-reducing bacteria followed by methanogens. An average pH of 8.4 (range of 8.2-8.6) and an average hydrogen concentration of 0.75% (range of 0.3-1.2%) observed between 6 and 15 months of the study were found to be conducive to sustaining the population of Dehalococcoides species in the three sediments amended with 0.01 g iron per g dry sediment. Biostimulation of indigenous PCB dechlorinators by the periodic amendment of contaminated sediments with low dosages of

  9. EXPLORATORY ANALYSIS OF THE EFFECTS OF PARTICULATE CHARACTERISTICS ON THE VARIATION IN PARTITIONING OF NONPOLAR ORGANIC CONTAMINANTS TO MARINE SEDIMENTS

    EPA Science Inventory

    The partitioning of nonpolar organic contaminants to marine sediments is considered to be controlled by the amount of organic carbon present. However, several studies propose that other characteristics of sediments may affect the partitioning of contaminants. For this exploratory...

  10. Impact of Highly Basic Solutions on Sorption of Cs+ to Subsurface Sediments from the Hanford Site, USA

    SciTech Connect

    Ainsworth, Calvin C.; Zachara, John M.; Wagnon, Ken B.; McKinley, Susan G.; Liu, Chongxuan; Smith, Steven C.; Schaef, Herbert T.; Gassman, Paul L.

    2005-11-28

    The effect of caustic NaNO3 solutions on the sorption of 137Cs to the Hanford site micaceous subsurface sediment was investigated as a function of time, temperature (10 C or 50 C), and NaOH concentration. At 100C and 0.1 M NaOH, the slow evolution of [Al]aq was in stack contrast to the rapid increase and subsequent loss of [Al]aq observed at 50 C (regardless of base concentration). At 50 C, dissolution of phyllosilicate minerals increased with [OH], at 1 and 3 M NaOH solutions, almost complete dissolution of clay-sized phyllosilicates occurred. At 0.1 M NaOH, a zeolite (tetranatrolite) precipitated after about 7 days, while an unnamed mineral phase (Na2Al2Si3O10?2H2O) precipitated after 4 and 2 days of exposure to 1 M and 3 M NaOH solutions. At 100C there was no conclusive evidence of secondary mineral precipitation. The effect of base dissolution on Cs+ sorption by the Hanford sediment was investigated via (1) Cs+ sorption over a large concentration range (10-9 ? 10-2 mol/L) to sediment after exposure to 0.1 M NaOH for 56, 112, and 168 days, (2) Cs+ sorption to sediment in the presence of NaOH (0.1 M, 1 M, and 3 M NaOH) at Cs+ concentrations selected to probe high affinity, transition, and low affinity cation exchange sites, and (3) the application of a two-site numeric ion exchange model (Zachara et al. 2002a). No effect on Cs+ sorption to the Hanford sediment was observed during the 168 days sediment was exposed to 0.1 M NaOH, at 10 C; Cs+ sorption in the presence of base was well described by the ion exchange model when enthalpy effects were considered. In contrast, at 50 C, there was a trend toward slightly lower (log {approx} 0.25) conditional equilibrium exchange constants over the entire range of surface coverage, and a slight loss of high affinity sites (15%) after 168 days of exposure to 0.1 M base solution. However, model simulations of Cs+ sorption to the sediment in the presence of 0.1 M base for 112 days were good at the lower Cs+ surface densities

  11. Secondary environmental impacts of remedial alternatives for sediment contaminated with hydrophobic organic contaminants.

    PubMed

    Choi, Yongju; Thompson, Jay M; Lin, Diana; Cho, Yeo-Myoung; Ismail, Niveen S; Hsieh, Ching-Hong; Luthy, Richard G

    2016-03-01

    This study evaluates secondary environmental impacts of various remedial alternatives for sediment contaminated with hydrophobic organic contaminants using life cycle assessment (LCA). Three alternatives including two conventional methods, dredge-and-fill and capping, and an innovative sediment treatment technique, in-situ activated carbon (AC) amendment, are compared for secondary environmental impacts by a case study for a site at Hunters Point Shipyard, San Francisco, CA. The LCA results show that capping generates substantially smaller impacts than dredge-and-fill and in-situ amendment using coal-based virgin AC. The secondary impacts from in-situ AC amendment can be reduced effectively by using recycled or wood-based virgin AC as production of these materials causes much smaller impacts than coal-based virgin AC. The secondary environmental impacts are highly sensitive to the dredged amount and the distance to a disposal site for dredging, the capping thickness and the distance to the cap materials for capping, and the AC dose for in-situ AC amendment. Based on the analysis, this study identifies strategies to minimize secondary impacts caused by different remediation activities: optimize the dredged amount, the capping thickness, or the AC dose by extensive site assessments, obtain source materials from local sites, and use recycled or bio-based AC. PMID:26590871

  12. A MULTI-ORD LAB AND REGIONAL ASSESSMENT OF MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC

    EPA Science Inventory

    Management of contaminated sediments poses many challenges due to varied contaminants and volumes of sediments to manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks. Understanding how well the ...

  13. Distributions of pesticides and organic contaminants between water and suspended sediment, San Francisco Bay, California

    USGS Publications Warehouse

    Domagalski, J.L.; Kuivila, K.M.

    1993-01-01

    Suspended-sediment and water samples were collected from San Francisco Bay in 1991 during low river discharge and after spring rains. All samples were analyzed for organophosphate, carbamate, and organochlorine pesticides; petroleum hydrocarbons; biomarkers; and polynuclear aromatic hydrocarbons. The objectives were to determine the concentrations of these contaminants in water and suspended sediment during two different hydrologic conditions and to determine partition coefficients of the contaminants between water and sediment. Concentrations of hydrophobic contaminants, such as polynuclear aromatic hydrocarbons, varied with location of sample collection, riverine discharge, and tidal cycle. Concentrations of hydrophobic contaminants in suspended sediments were highest during low river discharge but became diluted as agricultural soils entered the bay after spring rains. Polynuclear aromatic hydrocarbons defined as dissolved in the water column were not detected. The concentrations sorbed on suspended sediments were variable and were dependent on sediment transport patterns in the bay. In contrast, the relatively hydrophilic organophosphate pesticides, such as chlorpyrifos and diazinon, has a more uniform concentration in suspended sediment. These pesticides were detected only after spring rains. Most of the measured diazinon, at least 98% for all samples, was in the dissolved phase. Measured partition coefficients for diazinon generally were uniform, which suggests that suspended-sediment concentrations were close to equilibrium with dissolved concentrations. The concentration of diazinon sorbed to suspended sediments, at any given sampling site, was driven primarily by the more abundant solution concentration. The concentrations of diazinon sorbed to suspended sediments, therefore, were independent of the patterns of sediment movement. ?? 1993 Estuarine Research Federation.

  14. Patchy sediment contamination scenario and the habitat selection by an estuarine mudsnail.

    PubMed

    Araújo, Cristiano V M; Martinez-Haro, Mónica; Pais-Costa, Antónia J; Marques, João C; Ribeiro, Rui

    2016-03-01

    Since mudsnails are able to avoid contaminated sediment and that the contaminants in sediment are not uniformly distributed, the mudsnail Peringia ulvae was exposed to cadmium (Cd) spiked sediment and assessed for avoidance response in a heterogeneous contamination scenario. Four Cd concentrations were prepared and disposed in patches on dishes, which were divided in 25 fields (six fields for each sediment concentration); 24 organisms were deployed in the central field, with no sediment. Observations were made at 2, 4 and 6 h (corresponding to immediate response), 8, 10 and 12 h (very short term), and 24 h (short term). A trend to avoid contaminated patches was observed in the immediate and very short term. After 24 h exposure, the organisms exposed to the highest level of contamination seemed to have lost the ability to move and avoid contaminated patches. In a contamination scenario in which non- and contaminated sediment patches are heterogeneously distributed, local mudsnail populations can simply rearrange their locality without needing to move to a different habitat. Such less contaminated patches can become donor areas in a future recolonization scenario.

  15. Evaluation of the field-scale cation exchange capacity of Hanford sediments

    SciTech Connect

    Steefel, C.I.

    2003-02-01

    Three-dimensional simulations of unsaturated flow, transport, and multi-component, multi-site cation exchange in the vadose zone were used to analyze the migration of a plume resulting from a leak of the SX-115 tank at the Hanford site, USA. The match within about 0.5 meters of the positions of retarded sodium and potassium fronts suggests that the laboratory-derived parameters may be used in field-scale simulations of radionuclide migration at the Hanford site.

  16. Characterization of heavy-metal-contaminated sediment by using unsupervised multivariate techniques and health risk assessment.

    PubMed

    Wang, Yeuh-Bin; Liu, Chen-Wuing; Wang, Sheng-Wei

    2015-03-01

    This study characterized the sediment quality of the severely contaminated Erjen River in Taiwan by using multivariate analysis methods-including factor analysis (FA), self-organizing maps (SOMs), and positive matrix factorization (PMF)-and health risk assessment. The SOMs classified the dataset with similar heavy-metal-contaminated sediment into five groups. FA extracted three major factors-traditional electroplating and metal-surface processing factor, nontraditional heavy-metal-industry factor, and natural geological factor-which accounted for 80.8% of the variance. The SOMs and FA revealed the heavy-metal-contaminated-sediment hotspots in the middle and upper reaches of the major tributary in the dry season. The hazardous index value for health risk via ingestion was 0.302. PMF further qualified the source apportionment, indicating that traditional electroplating and metal-surface-processing industries comprised 47% of the health risk posed by heavy-metal-contaminated sediment. Contaminants discharged from traditional electroplating and metal-surface-processing industries in the middle and upper reaches of the major tributary must be eliminated first to improve the sediment quality in Erjen River. The proposed assessment framework for heavy-metal-contaminated sediment can be applied to contaminated-sediment river sites in other regions.

  17. Evolution of radioactive dose rates in fresh sediment deposits along coastal rivers draining Fukushima contamination plume.

    PubMed

    Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Patin, Jeremy; Lepage, Hugo; Lefèvre, Irène; Ayrault, Sophie; Ottlé, Catherine; Bonté, Philippe

    2013-10-29

    Measurement of radioactive dose rates in fine sediment that has recently deposited on channel bed-sand provides a solution to address the lack of continuous river monitoring in Fukushima Prefecture after Fukushima Dai-ichi nuclear power plant (FDNPP) accident. We show that coastal rivers of Eastern Fukushima Prefecture were rapidly supplied with sediment contaminated by radionuclides originating from inland mountain ranges, and that this contaminated material was partly exported by typhoons to the coastal plains as soon as by November 2011. This export was amplified during snowmelt and typhoons in 2012. In 2013, contamination levels measured in sediment found in the upper parts of the catchments were almost systematically lower than the ones measured in nearby soils, whereas their contamination was higher in the coastal plains. We thereby suggest that storage of contaminated sediment in reservoirs and in coastal sections of the river channels now represents the most crucial issue.

  18. Metal availability in a highly contaminated, dredged-sediment disposal site: field measurements and geochemical modeling.

    PubMed

    Lions, Julie; Guérin, Valérie; Bataillard, Philippe; van der Lee, Jan; Laboudigue, Agnès

    2010-09-01

    Two complementary approaches were used to characterize arsenic and metal mobilizations from a dredged-sediment disposal site: a detailed field study combined with hydrogeochemical modeling. Contaminants in sediments were found to be mainly present as sulfides subject to oxidation. Secondary phases (carbonates, sulfates, (hydr)oxides) were also observed. Oxidative processes occurred at different rates depending on physicochemical conditions and contaminant contents in the sediment. Two distinct areas were identified on the site, each corresponding to a specific contaminant mobility behavior. In a reducing area, Fe and As were highly soluble and illustrated anoxic behavior. In well-oxygenated material, groundwater was highly contaminated in Zn, Cd and Pb. A third zone in which sediments and groundwater were less contaminated was also characterized. This study enabled us to prioritize remediation work, which should aim to limit infiltration and long-term environmental impact.

  19. Evidence for mild sediment Pb contamination affecting leaf-litter decomposition in a lake.

    PubMed

    Oguma, Andrew Y; Klerks, Paul L

    2015-08-01

    Much work has focused on the effects of metal-contaminated sediment on benthic community structure, but effects on ecosystem functions have received far less attention. Decomposition has been widely used as an integrating metric of ecosystem function in lotic systems, but not for lentic ones. We assessed the relationship between low-level sediment lead (Pb) contamination and leaf-litter decomposition in a lentic system. We measured 30-day weight loss in 30 litter-bags that were deployed along a Pb-contamination gradient in a cypress-forested lake. At each deployment site we also quantified macrobenthos abundance, dissolved oxygen, water depth, sediment organic content, sediment silt/clay content, and both total sediment and porewater concentrations of Cd, Cu, Ni, Pb and Zn. Principal components (PC) analysis revealed a negative relationship between Pb concentration and benthic macroinvertebrate abundance, and this covariation dominated the first PC axis (PC1). Subsequent correlation analyses revealed a negative relationship between PC1 and percent leaf-litter loss. Our results indicate that leaf-litter decomposition was related to sediment Pb and benthic macroinvertebrate abundance. They also showed that ecosystem function may be affected even where sediment Pb concentrations are mostly below threshold-effects sediment quality guidelines--a finding with potential implications for sediment risk assessment. Additionally, the litter-bag technique used in this study showed promise as a tool in risk assessments of metal-contaminated sediments in lentic systems.

  20. Enhancing the intrinsic bioremediation of PAH-contaminated anoxic estuarine sediments with biostimulating agents.

    PubMed

    Bach, Quang-Dung; Kim, Sang-Jin; Choi, Sung-Chan; Oh, Young-Sook

    2005-08-01

    Estuarine sediments are frequently polluted with hydrocarbons from fuel spills and industrial wastes. Polycyclic aromatic hydrocarbons (PAHs) are components of these contaminants that tend to accumulate in the sediment due to their low aqueous solubility, low volatility, and high affinity for particulate matter. The toxic, recalcitrant, mutagenic, and carcinogenic nature of these compounds may require aggressive treatment to remediate polluted sites effectively. In petroleum-contaminated sediments near a petrochemical industry in Gwangyang Bay, Korea, in situ PAH concentrations ranged from 10 to 2,900 microg/kg dry sediment. To enhance the biodegradation rate of PAHs under anaerobic conditions, sediment samples were amended with biostimulating agents alone or in combination: nitrogen and phosphorus in the form of slow-release fertilizer (SRF), lactate, yeast extract (YE), and Tween 80. When added to the sediment individually, all tested agents enhanced the degradation of PAHs, including naphthalene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, and benzo[a]pyrene. Moreover, the combination of SRF, Tween 80, and lactate increased the PAH degradation rate 1.2-8.2 times above that of untreated sediment (0.01-10 microg PAH/kg dry sediment/day). Our results indicated that in situ contaminant PAHs in anoxic sediment, including high molecular weight PAHs, were degraded biologically and that the addition of stimulators increased the biodegradation potential of the intrinsic microbial populations. Our results will contribute to the development of new strategies for in situ treatment of PAH-contaminated anoxic sediments.

  1. Chemical information on tank supernatants, Cs adsorption from tank liquids onto Hanford sediments, and field observations of Cs migration from past tank leaks

    SciTech Connect

    Serne, R.J.; Zachara, J.M.; Burke, D.S.

    1998-01-01

    Borehole gamma-logging profiles beneath the SX-Tank Farm suggest that contamination from Cs-137 extends to at least a depth of 40 m (130 ft), and may extend even deeper. What is presently not known is the pathway that Cs-137 has taken to reach these depths. In this report we provide an analysis of the chemistry of tank supernates with emphasis on the REDOX waste stream disposed in SX tanks, Cs chemistry in aqueous solutions and adsorption properties onto minerals, available data on Cs adsorption onto Hanford sediments, and information on Cs migration from other Hanford tank leaks that have been studied. The data in this report was used to help guide the vadose zone transport analysis of the SX Tank Farm presented in a companion report. The goal of the vadose zone transport modelling is to attempt to explain the depth and extent of the Cs-137 plume under the SX Tank farm, specifically in the vicinity of the greatest leak, near the SX-109 Tank as inferred from the gamma logs (DOE 1996). In solution Cs is present as the monovalent cation and shows very little tendency to form aqueous complexes with inorganic or organic ligands. Cs is expected to adsorb primarily onto selective minerals that have unique adsorption sites. The small Cs{sup +} ion is accommodated on these frayed edge and interlayer sites. Adsorption within the interlayers often leads to collapse of the layers such that the Cs{sup +} ion is effectively trapped and not readily exchangeable by all other common cations. The degree of adsorption is thus only moderately dependent on the types and high concentrations of other cations in leaking tank liquors.

  2. Characterization of the Contaminated Soil Under the Hanford 324 Building B Cell, Washington, USA - 12182

    SciTech Connect

    Josephson, Walter S.

    2012-07-01

    The 324 Building on the Hanford site played a key role in radiochemical and metallurgical research programs conducted by DOE. The B hot cell in the 324 Building was the site of high-level waste vitrification research. During clean-out operations in November 2009, a tear was noted in the stainless steel liner on the floor of B Cell. Exposure rate readings taken at various locations in the soil about 0.5 meters below B Cell reached 8,900 Roentgen (R) per hour, confirming the existence of a significant soil contamination field. The source of the radioactive material was likely a 510 L spill from the Canister Fabrication Project, consisting of purified, concentrated Cs-137 and Sr-90 solutions totaling 48,000 TBq (1.3 MCi). MCNP modeling was used to estimate that the measured exposure rates were caused by 5,900 TBq (160 kCi) of Sr- 90 and Cs-137, although additional contamination was thought to exist deeper in the soil column. Two physical soil samples were obtained at different depths, which helped verify the contamination estimates. A detailed exposure rate survey inside B Cell was combined with additional MCNP modeling to estimate that an additional 1,700 TBq (460 kCi) is present just below the floor. Based on the results of the sampling campaign, it is likely that the radioactive material below B Cell is primarily consists of feed solutions from the FRG Canister Fabrication Project, and that it contains purified Sr-90 and Cs-137 with enough actinide carryover to make some of the soil transuranic. The close agreement between the Geoprobe calculations and the physical samples adds confidence that there are more than 3700 TBq (100,000 Ci) of Sr-90 and Cs-137 in the soil approximately 1 meter below the cell floor. The majority of the Cs-137 is contained in the first meter of soil, while significant Sr-90 contamination extends to 10 meters below the cell floor. It is also likely that an additional 15,000 TBq (400,000 Ci) of Cs-137 and Sr-90 activity is present directly

  3. Resolving the unresolved complex mixture in petroleum-contaminated sediments.

    PubMed

    Frysinger, Glenn S; Gaines, Richard B; Xu, Li; Reddy, Christopher M

    2003-04-15

    Comprehensive two-dimensional gas chromatography (GC x GC) was used to investigate the chemical composition of the unresolved complex mixture (UCM) of hydrocarbons in petroleum-contaminated marine sediments. The UCM hydrocarbons were extracted and separated with silica and silver-impregnated silica gel chromatography to yield four fractions (branched alkanes and cycloalkanes, monoaromatics, naphthalenes, and multi-ring PAHs) prior to GC x GC analysis. GC x GC separations used a poly-(dimethylsiloxane) stationary phase for volatility selectivity on the first dimension and a 14% cyanopropylphenyl polysiloxane phase for polarity selectivity on the second dimension to fully resolve monoaromatic, naphthalene, and multi-ring PAH compounds from the UCM. A chiral gamma-cyclodextrin phase was used for shape selectivity on the second GC x GC dimension to resolve individual branched alkanes and cycloalkanes in the saturates fraction of the UCM. The ability of GC x GC to resolve thousands of individual chemical components from the UCM will facilitate an understanding of the sources, weathering, and toxicity of UCM hydrocarbons.

  4. Radionuclide Activities in Contaminated Soils: Effects of Sampling Bias on Remediation of Coarse-Grained Soils in Hanford Formation

    SciTech Connect

    Mattigod, Shas V.; Martin, Wayne J.

    2001-08-28

    Only a limited set of particle size-contaminant concentration data is available for soils from the Hanford Site. These data are based on bench-scale tests on single soil samples from one waste site each in operable units 100-BC-1, 100-DR-1, and 100-FR-1, and three samples from the North Pond 300-FF-1 operable unit. The objective of this study was to 1) examine available particle size-contaminant of concern activity and concentration data for 100 and 300 Area soils, 2) assess the effects of sampling bias, 3) suggest sampling protocols, and 4) formulate a method to determine the contaminant of concern activities and concentrations of the whole soil based on the measurements conducted on a finer size fraction of the whole soil.

  5. Quantifying the dilution of the radiocesium contamination in Fukushima coastal river sediment (2011–2015)

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Laceby, J. Patrick; Onda, Yuichi; Wakiyama, Yoshifumi; Jaegler, Hugo; Lefèvre, Irène

    2016-10-01

    Fallout from the Fukushima Dai-ichi nuclear power plant accident resulted in a 3000-km2 radioactive contamination plume. Here, we model the progressive dilution of the radiocesium contamination in 327 sediment samples from two neighboring catchments with different timing of soil decontamination. Overall, we demonstrate that there has been a ~90% decrease of the contribution of upstream contaminated soils to sediment transiting the coastal plains between 2012 (median – M – contribution of 73%, mean absolute deviation – MAD – of 27%) and 2015 (M 9%, MAD 6%). The occurrence of typhoons and the progress of decontamination in different tributaries of the Niida River resulted in temporary increases in local contamination. However, the much lower contribution of upstream contaminated soils to coastal plain sediment in November 2015 demonstrates that the source of the easily erodible, contaminated material has potentially been removed by decontamination, diluted by subsoils, or eroded and transported to the Pacific Ocean.

  6. Quantifying the dilution of the radiocesium contamination in Fukushima coastal river sediment (2011–2015)

    PubMed Central

    Evrard, Olivier; Laceby, J. Patrick; Onda, Yuichi; Wakiyama, Yoshifumi; Jaegler, Hugo; Lefèvre, Irène

    2016-01-01

    Fallout from the Fukushima Dai-ichi nuclear power plant accident resulted in a 3000-km2 radioactive contamination plume. Here, we model the progressive dilution of the radiocesium contamination in 327 sediment samples from two neighboring catchments with different timing of soil decontamination. Overall, we demonstrate that there has been a ~90% decrease of the contribution of upstream contaminated soils to sediment transiting the coastal plains between 2012 (median – M – contribution of 73%, mean absolute deviation – MAD – of 27%) and 2015 (M 9%, MAD 6%). The occurrence of typhoons and the progress of decontamination in different tributaries of the Niida River resulted in temporary increases in local contamination. However, the much lower contribution of upstream contaminated soils to coastal plain sediment in November 2015 demonstrates that the source of the easily erodible, contaminated material has potentially been removed by decontamination, diluted by subsoils, or eroded and transported to the Pacific Ocean. PMID:27694832

  7. Mobilization of PAHs and PCBs from In-Place Contaminated Marine Sediments During Simulated Resuspension Events

    NASA Astrophysics Data System (ADS)

    Latimer, J. S.; Davis, W. R.; Keith, D. J.

    1999-10-01

    A particle entrainment simulator was used to experimentally produce representative estuarine resuspension conditions to investigate the resulting transport of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) to the overlying water column. Contaminants were evaluated in bulk sediments, size fractionated sediments, resuspended particulate material and in some cases, dissolved phases during the experiments. The two types of sediments used in the experiments, dredged material and bedded estuarine sediment, represented gradients in contaminant loadings and sediment textural characteristics. For the bedded sediment, resuspension tended to winnow the sediments of finer particles. However, in the case of the more highly contaminated dredge material, non-selective resuspension was most common. Resuspension resulted in up to orders of magnitude higher particle-bound organic contaminant concentrations in the overlying water column. Dissolved phase PAH changes during resuspension were variable and at most, increased by a factor of three. The sifting process resulted in the partitioning of fine and coarse particle contaminant loading. For bedded sediments, accurate predictions of PAH and PCB loadings on resuspended particles were made using the mass of resuspended particles of different sizes and the concentrations of contaminants in the particle pools of the bulk sediment. However, due possibly to contributions from other unmeasured particles (e.g. colloids), predictions were not possible for the dredge material. Thus, knowledge of the redistribution and fate of colloids may be important. The partitioning of PAHs between the dissolved and particulate phases during resuspension events was predicted to within a factor of two from the amount of organic carbon in each of the resuspended samples. These experiments show that contaminant transport is a function of the chemistry and textural characteristics of the bulk sediment and the winnowing action

  8. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: Methodology and applications

    USGS Publications Warehouse

    Mahler, B.J.; Van Metre, P.C.

    2003-01-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

  9. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: methodology and applications.

    PubMed

    Mahler, B J; Van Metre, P C

    2003-04-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport.

  10. A simplified approach for monitoring hydrophobic organic contaminants associated with suspended sediment: methodology and applications.

    PubMed

    Mahler, B J; Van Metre, P C

    2003-04-01

    Hydrophobic organic contaminants, although frequently detected in bed sediment and in aquatic biota, are rarely detected in whole-water samples, complicating determination of their occurrence, load, and source. A better approach for the investigation of hydrophobic organic contaminants is the direct analysis of sediment in suspension, but procedures for doing so are expensive and cumbersome. We describe a simple, inexpensive methodology for the dewatering of sediment and present the results of two case studies. Isolation of a sufficient mass of sediment for analyses of organochlorine compounds and PAHs is obtained by in-line filtration of large volumes of water. The sediment is removed from the filters and analyzed directly by standard laboratory methods. In the first case study, suspended-sediment sampling was used to determine occurrence, loads, and yields of contaminants in urban runoff affecting biota in Town Lake, Austin, TX. The second case study used suspended-sediment sampling to locate a point source of PCBs in the Donna Canal in south Texas, where fish are contaminated with PCBs. The case studies demonstrate that suspended-sediment sampling can be an effective tool for determining the occurrence, load, and source of hydrophobic organic contaminants in transport. PMID:12712287

  11. Iron reduction in the sediments of a hydrocarbon-contaminated aquifer

    USGS Publications Warehouse

    Tuccillo, M.E.; Cozzarelli, I.M.; Herman, J.S.

    1999-01-01

    Sediments sampled at a hydrocarbon-contaminated, glacial-outwash, sandy aquifer near Bemidji, Minnesota, were analyzed for sediment-associated Fe with several techniques. Extraction with 0.5 M HCl dissolved poorly crystalline Fe oxides and small amounts of Fe in crystalline Fe oxides, and extracted Fe from phyllosilicates. Use of Ti-citrate-EDTA-bicarbonate results in more complete removal of crystalline Fe oxides. The average HCl-extractable Fe(III) concentration in the sediments closest to the crude-oil contamination (16.2 ??mol/g) has been reduced by up to 30% from background values (23.8 ??mol/g) as a result of Fe(III) reduction in contaminated anoxic groundwater. Iron(II) concentrations are elevated in sediments within an anoxic plume in the aquifer. Iron(II) values under the oil body (19.2 ??mol/g) are as much as 4 times those in the background sediments (4.6 ??mol/g), indicating incorporation of reduced Fe in the contaminated sediments. A 70% increase in total extractable Fe at the anoxic/oxic transition zone indicates reoxidation and precipitation of Fe mobilized from sediment in the anoxic plume. Scanning electron microscopy detected authigenic ferroan calcite in the anoxic sediments and confirmed abundant Fe(III) oxyhydroxides at the anoxic/oxic boundary. The redox biogeochemistry of Fe in this system is coupled to contaminant degradation and is important in predicting processes of hydrocarbon degradation.

  12. Hanford Tanks 241-C-203 and 241-C-204: Residual Waste Contaminant Release Model and Supporting Data

    SciTech Connect

    Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

    2004-10-28

    This report describes the development of release models for key contaminants that are present in residual sludge remaining after closure of Hanford Tanks 241-C-203 (C-203) and 241-C-204 (C-204). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. Key results from this work are (1) future releases from the tanks of the primary contaminants of concern (99Tc and 238U) can be represented by relatively simple solubility relationships between infiltrating water and solid phases containing the contaminants; and (2) high percentages of technetium-99 in the sludges (20 wt% in C-203 and 75 wt% in C-204) are not readily water leachable, and, in fact, are very recalcitrant. This is similar to results found in related studies of sludges from Tank AY-102. These release models are being developed to support the tank closure risk assessments performed by CH2M HILL Hanford Group, Inc., for the U.S. Department of Energy.

  13. Hanford Tanks 241-C-203 and 241 C 204: Residual Waste Contaminant Release Model and Supporting Data

    SciTech Connect

    Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

    2007-05-23

    This report was revised in May 2007 to correct 90Sr values in Chapter 3. The changes were made on page 3.9, paragraph two and Table 3.10; page 3.16, last paragraph on the page; and Tables 3.21 and 3.31. The rest of the text remains unchanged from the original report issued in October 2004. This report describes the development of release models for key contaminants that are present in residual sludge remaining after closure of Hanford Tanks 241-C-203 (C-203) and 241-C-204 (C-204). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. Key results from this work are (1) future releases from the tanks of the primary contaminants of concern (99Tc and 238U) can be represented by relatively simple solubility relationships between infiltrating water and solid phases containing the contaminants; and (2) high percentages of technetium-99 in the sludges (20 wt% in C-203 and 75 wt% in C-204) are not readily water leachable, and, in fact, are very recalcitrant. This is similar to results found in related studies of sludges from Tank AY-102. These release models are being developed to support the tank closure risk assessments performed by CH2M HILL Hanford Group, Inc., for the U.S. Department of Energy.

  14. Response of estuarine benthic communities to zinc contamination: Tests using formulated sediments

    SciTech Connect

    Watzin, M.C.; Roscigno, P.F.

    1994-12-31

    Because of historic industrial sources, zinc contamination in Mobile Bay is of widespread concern. Using formulated sediment and a newly developed field technique, the authors examined the effects of a series of concentrations of zinc on the benthic invertebrate community at two sites. A formulated sediment that matches field sediment in grain size distribution and organic matter content was mixed from 11 components and used as the test substrate. Clean sediments and sediments dosed with zinc at concentrations from 250--5,000 mg/kg were exposed in the field on holding racks anchored on the bottom of the bay. The abundance and diversity of benthic invertebrate recruits were used as indicators of sediment quality. The authors found significant differences in both the abundances and species composition of recruits between clean controls and the zinc contaminated sediments. All taxa did not respond similarly to changing zinc concentrations, and effects on some groups were more apparent at lower concentrations. Several families of polychaete worms, harpacticoid copepods, and ostracods appeared to be most sensitive to the zinc. Under certain conditions, some taxa were attracted to zinc contaminated sediments. Taken together, the results suggest that zinc contamination can profoundly affect the nature of the benthic community recruiting into such sediments.

  15. Environmental impact of ongoing sources of metal contamination on remediated sediments

    DOE PAGES

    Knox, Anna Sophia; Paller, Michael H.; Milliken, Charles E.; Redder, Todd M.; Wolfe, John R.; Seaman, John

    2016-04-29

    One challenge to all remedial approaches for contaminated sediments is the continued influx of contaminants from uncontrolled sources following remediation. We investigated the effects of ongoing contamination in mesocosms employing sediments remediated by different types of active and passive caps and in-situ treatment. Our hypothesis was that the sequestering agents used in active caps and in situ treatment will bind elements (arsenic, chromium, cadmium, cobalt, copper, nickel, lead, selenium, and zinc) from ongoing sources thereby reducing their bioavailability and protecting underlying remediated sediments from recontamination. Most element concentrations in surface water remained significantly lower in mesocosms with apatite and mixedmore » amendment caps than in mesocosms with passive caps (sand), uncapped sediment, and spike solution throughout the 2520 hour experiment. Element concentrations were significantly higher in Lumbriculus variegatus from untreated sediment than in Lumbriculus from most active caps. Moreover, Pearson correlations between element concentrations in Lumbriculus and metal concentrations in the top 2.5 cm of sediment or cap measured by diffusive gradient in thin films (DGT) sediment probes were generally strong (as high as 0.98) and significant (p<0.05) for almost all tested elements. Metal concentrations in both Lumbriculus and sediment/cap were lowest in apatite, mixed amendment, and activated carbon treatments. Finally, these findings show that some active caps can protect remediated sediments by reducing the bioavailable pool of metals/metalloids in ongoing sources of contamination.« less

  16. An evaluation of the toxicity of contaminated sediments from Waukegan Harbor, Illinois, following remediation

    USGS Publications Warehouse

    Kemble, N.E.; Hardesty, D.G.; Ingersoll, C.G.; Johnson, B.T.; Dwyer, F.J.; MacDonald, D.D.

    2000-01-01

    Waukegan Harbor in Illinois was designated as a Great Lakes Area of Concern due to high concentrations of sediment-associated polychlorinated biphenyls (PCBs). The objective of this study was to evaluate the toxicity of 20 sediment samples collected after remediation (primarily dredging) of Waukegan Harbor for PCBs. A 42-day whole sediment toxicity test with the amphipod Hyalella azteca (28-day sediment exposure followed by a 14-day reproductive phase) and sediment toxicity tests with Microtox® were conducted to evaluate sediments from Waukegan Harbor. Endpoints measured were survival, growth, and reproduction (amphipods) and luminescent light emission (bacteria). Survival of amphipods was significantly reduced in 6 of the 20 sediment samples relative to the control. Growth of amphipods (either length or weight) was significantly reduced relative to the control in all samples. However, reproduction of amphipods identified only two samples as toxic relative to the control. The Microtox basic test, conducted with organic extracts of sediments identified only one site as toxic. In contrast, the Microtox solid-phase test identified about 50% of the samples as toxic. A significant negative correlation was observed between reproduction and the concentration of three polynuclear aromatic hydrocarbons (PAHs) normalized to total organic carbon. Sediment chemistry and toxicity data were evaluated using sediment quality guidelines (consensus-based probable effect concentrations, PECs). Results of these analyses indicate that sediment samples from Waukegan Harbor were toxic to H. azteca contaminated at similar contaminant concentrations as sediment samples that were toxic to H. azteca from other areas of the United States. The relationship between PECs and the observed toxicity was not as strong for the Microtox test. The results of this study indicate that the first phase of sediment remediation in Waukegan Harbor successfully lowered concentrations of PCBs at the site

  17. Relating groundwater and sediment chemistry to microbial characterization at a BTEX-contaminated site

    SciTech Connect

    Pfiffner, S.M.; Palumbo, A.V.; McCarthy, J.F.; Gibson, T.

    1996-07-01

    The National Center for Manufacturing Science is investigating bioremediation of petroleum hydrocarbon at a site in Belleville, Michigan. As part of this study we examined the microbial communities to help elucidate biodegradative processes currently active at the site. We observed high densities of aerobic hydrocarbon degraders and denitrifiers in the less-contaminated sediments. Low densities of iron and sulfate reducers were measured in the same sediments. In contrast, the highly-contaminated sediments showed low densities of aerobic hydrocarbon degraders and denitrifiers and high densities of iron and sulfate reducers. Methanogens were also found in these highly-contaminated sediments. These contaminated sediments also showed a higher biomass, by phospholipid fatty acids, and greater ratios of phospholipid fatty acids which indicate stress within the microbial community. Aquifer chemistry analyses indicated that the more-contaminated area was more reduced and had lower sulfate than the less-contaminated area. These conditions suggest that the subsurface environment at the highly-contaminated area had progressed into sulfate reduction and methanogensis. The less-contaminated area, although less reduced, also appeared to be progressing into primarily iron- and sulfate-reducing microbial communities. The proposed treatment to stimulate bioremediation includes addition of oxygen and nitrate. Groundwater chemistry and microbial analyses revealed significant differences resulted from the injection of dissolved oxygen and nitrate in the subsurface. These differences included increases in pH and Eh and large decreases in BTEX, dissolved iron, and sulfate concentrations at the injection well.

  18. Phototoxic evaluation of marine sediments collected from a PAH-contaminated site.

    PubMed

    Boese, B L; Ozretich, R J; Lamberson, J O; Cole, F A; Swartz, R C; Ferraro, S P

    2000-04-01

    The phototoxicity potential of PAH-contaminated field sediment was evaluated and compared to standard sediment toxicity test results. Marine sediments were collected from 30 sites along a presumed PAH sediment pollution gradient in Elliot Bay, WA. Standard 10-day acute and 28-day chronic sediment toxicity tests were conducted with the infaunal amphipods Rhepoxynius abronius and Leptocheirus plumulosus using mortality and the ability to rebury as endpoints. The survivors of these tests were then subjected to 1-h exposures to UV radiation with mortality and reburial again determined. The most highly toxic sediments identified in these experiments were evaluated further for toxicity and phototoxicity by serially diluting them with uncontaminated sediment and repeating the toxicity tests. Standard 10-day toxicity test results indicated that over 70% of the sites sampled in Elliot Bay exhibited measurable toxicity with nine sites being highly toxic to both species of amphipods. Results of standard 28-day chronic sediment toxicity tests were similar. In contrast, almost all of the sites were found to be highly phototoxic. Results indicated that exposure to UV increased toxicity five- to eightfold. This suggests that standard toxicity tests underestimate the potential ecological risk of PAH-contaminated sediments in animals exposed to sunlight. However, only when PAH contamination was between 0.05 and 1.0 toxic units would conducting a phototoxicity evaluation add information to that gained from conducting a standard sediment toxicity test alone.

  19. DEVELOPING TOOLS FOR MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS AT LAKE HARTWELL, SC

    EPA Science Inventory

    Contaminated sediments pose a risk to human health and the environment . The management of this risk is currently limited practically to three technologies: dredging, capping, and natural recovery. Monitored natural recovery relies on the natural burial and removal mechanisms to...

  20. A Feasibility Study On Pd/Mg Application In Historically Contaminated Sediments And PCB Spiked Substrates

    EPA Science Inventory

    A vast majority of literature on bimetals deals with aqueous contaminants, very little being on organics strongly adsorbed on sediments and hence very challenging to remediate. Having previously reported materials, mechanistic and parametric aspects of PCB dechlorination with Pd...

  1. EPA'S FIELD DEMONSTRATION OF INNOVATIVE CAPPING TECHNOLOGIES FOR THE RISK MANAGEMENT OF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Research on capping technologies is directed at assessing the effectiveness of innovative capping materials, factors that control contaminant release at the sediment-water interface, installation of cap, resuspension mechanism, and gas ebullition. U.S. EPA's Land Remediation and ...

  2. A TOXICITY ASSESSMENT APPROACH FOR EVALUATION OF IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) represent a group of organic contaminants known for their prevalence and persistence in petroleum-impacted environment such as groundwater, soils and sediments. Many high molecular weight PAHs are suspected carcinogens and the existence of...

  3. Selecting Performance Reference Compounds (PRCS)for Polyethylene Passive Samplers Deployed at Contaminated Sediment Sites

    EPA Science Inventory

    Use of equilibrium passive samplers for performing aquatic environmental monitoring at contaminated sediment sites, including Superfund sites, is becoming more common. However, a current challenge in passive sampling is determining when equilibrium is achieved between the sampl...

  4. Selective removal of organic contaminants from sediments: A methodology for toxicity identification evaluations (TIEs)

    USGS Publications Warehouse

    Lebo, J.A.; Huckins, J.N.; Petty, J.D.; Ho, K.T.; Stern, E.A.

    2000-01-01

    Aqueous slurries of a test sediment spiked with dibenz[a,h]anthracene, 2,4,5,2',4',5'-hexachlorobiphenyl, p,p'-DDE, or phenanthrene were subjected to decontamination experimentation. The spiked sediments were agitated at elevated temperatures for at least 96 h in the presence of either of the two contaminant-absorbing media: clusters of polyethylene membrane or lipid- containing semipermeable membrane devices (SPMDs). The effects of treatment temperature and surface area of media on the removal of contaminants were explored. This work is part of a larger methodology for whole-sediment toxicity identification evaluation (TIE). A method is being sought that is capable of detoxifying sediments with respect to organic contaminants while leaving toxicity attributable to inorganic contaminants unaffected. (C) 2000 Elsevier Science Ltd.

  5. STUDIES ON BIOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON-CONTAMINATED SEDIMENTS: BIOAVAILABILITY, BIODEGRADABILITY, AND TOXICITY ISSUES

    EPA Science Inventory

    The widespread contamination of aquatic sediments by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes, on which the bioavailability and the toxicity of PAHs often have a significant impact. This research investigated the biode...

  6. EVIDENCE FOR MICROBIAL ENHANCED ELECTRICAL CONDUCTIVITY IN HYDROCARBON-CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Electrical conductivity of sediments during microbial mineralization of diesel was investigated in a mesoscale column experiment consisting of biotic contaminated and uncontaminated columns. Microbial population numbers increased with a clear pattern of depth zonation within the ...

  7. Using Nitrogen and Oxygen Isotope Compositions of Nitrate to Distinguish Contaminant Sources in Hanford Soil and Groundwater

    SciTech Connect

    Conrad, Mark; Bill, Markus

    2008-08-01

    The nitrogen ({delta}{sup 15}N) and oxygen ({delta}{sup 18}O) isotopic compositions of nitrate in the environment are primarily a function of the source of the nitrate. The ranges of isotopic compositions for nitrate resulting from common sources are outlined in Figure 1 from Kendall (1998). As noted on Figure 1, processes such as microbial metabolism can modify the isotopic compositions of the nitrate, but the effects of these processes are generally predictable. At Hanford, nitrate and other nitrogenous compounds were significant components of most of the chemical processes used at the site. Most of the oxygen in nitrate chemicals (e.g., nitric acid) is derived from atmospheric oxygen, giving it a significantly higher {delta}{sup 18}O value (+23.5{per_thousand}) than naturally occurring nitrate that obtains most of its oxygen from water (the {delta}{sup 18}O of Hanford groundwater ranges from -14{per_thousand} to -18{per_thousand}). This makes it possible to differentiate nitrate from Hanford site activities from background nitrate at the site (including most fertilizers that might have been used prior to the Department of Energy plutonium production activities at the site). In addition, the extreme thermal and chemical conditions that occurred during some of the waste processing procedures and subsequent waste storage in select single-shell tanks resulted in unique nitrate isotopic compositions that can be used to identify those waste streams in soil and groundwater at the site (Singleton et al., 2005; Christensen et al., 2007). This report presents nitrate isotope data for soil and groundwater samples from the Hanford 200 Areas and discusses the implications of that data for potential sources of groundwater contamination.

  8. Arsenic, lead, and other trace elements in soils contaminated with pesticide residues at the Hanford site (USA).

    PubMed

    Yokel, Jerry; Delistraty, Damon A

    2003-04-01

    The primary purpose of this study was to characterize arsenic (As) and lead (Pb) concentrations in former orchard soils contaminated with lead arsenate pesticides at the Hanford site in Washington state (USA). Surface samples (n = 31) were collected from former orchard soils (in cultivation during the pre-Hanford period) at five locations at the 100 Areas and at one location at the Old Hanford Townsite (OHT). Another set of samples (n = 17) was collected over a soil depth interval of 10-50 cm at the four locations with the highest As and Pb surface concentrations. All samples were analyzed for 22 trace elements (including As and Pb) with inductively coupled plasma-atomic emission spectrometry (ICP-AES). The mean, standard deviation, and range for As in the surface soils were 30, 61, and 2.9-270 mg/kg dry wt, respectively. The corresponding statistics for Pb were 220, 460, and 6.5-1900 mg/kg dry wt, respectively. As and Pb concentrations in the surface soils were positively and significantly correlated (r = 0.91, Bonferroni p < 0.05). Descriptive statistics and bivariate correlations were also computed for other trace elements. As and Pb mean concentrations in the surface soils each differed significantly (p < 0.05) among Hanford locations, with the highest concentrations at the 100-H and 100-F Areas. Although both As and Pb mean concentrations decreased with soil depth, regression and correlation coefficients only, for Pb significantly differed from zero (b = -0.0372, r = -0.805, Bonferroni p < 0.05). Compared with data in the literature As and Pb concentrations found in this study exceeded background levels but were typical of orchard soils. Furthermore, mean As and Pb soil concentrations were in the range of various toxicological benchmarks derived for protection of human and ecological receptors.

  9. Accelerating progress at contaminated sediment sites: moving from guidance to practice.

    PubMed

    Bridges, Todd S; Nadeau, Steven C; McCulloch, Megan C

    2012-04-01

    Contaminated sediments are a pervasive problem in the United States. Significant economic, ecological, and social issues are intertwined in addressing the nation's contaminated sediment problem. Managing contaminated sediments has become increasingly resource intensive, with some investigations costing tens of millions of dollars and the majority of remediation projects proceeding at a slow pace. At present, the approaches typically used to investigate, evaluate, and remediate contaminated sediment sites in the United States have largely fallen short of producing timely, risk-based, cost-effective, long-term solutions. With the purpose of identifying opportunities for accelerating progress at contaminated sediment sites, the US Army Corps of Engineers-Engineer Research and Development Center and the Sediment Management Work Group convened a workshop with experienced experts from government, industry, consulting, and academia. Workshop participants identified 5 actions that, if implemented, would accelerate the progress and increase the effectiveness of risk management at contaminated sediment sites. These actions included: 1) development of a detailed and explicit project vision and accompanying objectives, achievable short-term and long-term goals, and metrics of remedy success at the outset of a project, with refinement occurring as needed throughout the duration of the project; 2) strategic engagement of stakeholders in a more direct and meaningful process; 3) optimization of risk reduction, risk management processes, and remedy selection addressing 2 important elements: a) the deliberate use of early action remedies, where appropriate, to accelerate risk reduction; and b) the systematic and sequential development of a suite of actions applicable to the ultimate remedy, starting with monitored natural recovery and adding engineering actions as needed to satisfy the project's objectives; 4) an incentive process that encourages and rewards risk reduction; and 5

  10. Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques.

    PubMed

    Benson, Nsikak U; Asuquo, Francis E; Williams, Akan B; Essien, Joseph P; Ekong, Cyril I; Akpabio, Otobong; Olajire, Abaas A

    2016-01-01

    Trace metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources. PMID:27257934

  11. Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques.

    PubMed

    Benson, Nsikak U; Asuquo, Francis E; Williams, Akan B; Essien, Joseph P; Ekong, Cyril I; Akpabio, Otobong; Olajire, Abaas A

    2016-01-01

    Trace metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources.

  12. Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

    PubMed Central

    Benson, Nsikak U.; Asuquo, Francis E.; Williams, Akan B.; Essien, Joseph P.; Ekong, Cyril I.; Akpabio, Otobong; Olajire, Abaas A.

    2016-01-01

    Trace metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources. PMID:27257934

  13. Characterization and FATE of PAH-contaminated sediments at the Wyckoff/Eagle Harbor Superfund Site.

    PubMed

    Brenner, Richard C; Magar, Victor S; Ickes, Jennifer A; Abbott, James E; Stout, Scott A; Crecelius, Eric A; Bingler, Linda S

    2002-06-15

    Eagle Harbor, a shallow marine embayment of Bainbridge Island, WA approximately 10 miles west of Seattle, WA), was formerly the site of the Wyckoff wood-treatment facility. The facility used large quantities of creosote in its wood-treating processes from the early 1900s to 1988. Historical creosote seepage into the harbor resulted in substantial accumulation of polycyclic aromatic hydrocarbon (PAH) contamination in the harbor sediments over time. This investigation focused on the distribution and fate of the PAH-contaminated harbor sediments. Analyses of 10 sediment cores using total petroleum hydrocarbon (TPH) fingerprinting, the distribution of 50 PAH analytes, and sediment age dating revealed the contributions of three distinct sources of PAHs to sediment contamination in the harbor during various periods over the past 100 years; namely, creosote, urban runoff, and natural background. Surface sediments (upper 20-30 cm) in the cores closestto the Wyckoff wood-treatment facility and southeast of an existing cap were dominated by urban runoff and weathered creosote; the deeper sediments (> 30 cm) were heavily contaminated with relatively unweathered creosote and some pure-phase creosote. Cores located the furthest from the area of contamination, in the center of the harbor, were dominated by urban runoff, showed no signs of creosote contamination, and had much lower PAH and TPH concentrations than those adjacent to the facility. In the four cores in the center of the Harbor, farthest from the former Wyckoff facility, PAH concentrations increased significantly (p < 0.01) with proximity to the northern shore of the harbor, which is more heavily developed than the southern shore and is where all automobile traffic enters and exits the island through the Bainbridge Island ferry terminal. Deeper portions of these cores were contaminated primarily with natural background PAHs, likely representing preurbanization sediments. Sedimentation rates ranged from 0.54 to 1.10 gm

  14. Sediment-hosted contaminants and distribution patterns in the Mississippi and Atchafalaya River Deltas

    USGS Publications Warehouse

    Flocks, James G.; Kindinger, Jack G.; Ferina, Nicholas; Dreher, Chandra

    2002-01-01

    The Mississippi and Atchafalaya Rivers transport very large amounts of bedload and suspended sediments to the deltaic and coastal environments of the northern Gulf of Mexico. Absorbed onto these sediments are contaminants that may be detrimental to the environment. To adequately assess the impact of these contaminants it is first necessary to develop an understanding of sediment distribution patterns in these deltaic systems. The distribution patterns are defined by deltaic progradational cycles. Once these patterns are identified, the natural and industrial contaminant inventories and their depositional histories can be reconstructed. Delta progradation is a function of sediment discharge, as well as channel and receiving-basin dimensions. Fluvial energy controls the sediment distribution pattern, resulting in a coarse grained or sandy framework, infilled with finer grained material occupying the overbank, interdistributary bays, wetlands and abandoned channels. It has been shown that these fine-grained sediments can carry contaminants through absorption and intern them in the sediment column or redistribute them depending on progradation or degradation of the delta deposit. Sediment distribution patterns in delta complexes can be determined through high-resolution geophysical surveys and groundtruthed with direct sampling. In the Atchafalaya and Mississippi deltas, remote sensing using High-Resolution Single-Channel Seismic Profiling (HRSP) and Sidescan Sonar was correlated to 20-ft vibracores to develop a near-surface geologic framework that identifies variability in recent sediment distribution patterns. The surveys identified bedload sand waves, abandoned-channel back-fill, prodelta and distributary mouth bars within the most recently active portions of the deltas. These depositional features respond to changes in deltaic processes and through their response may intern or transport absorbed contaminants. Characterizing these features provides insight into the

  15. Mobile sediment in an urbanizing karst aquifer: Implications for contaminant transport

    USGS Publications Warehouse

    Mahler, B.J.; Lynch, L.; Bennett, P.C.

    2000-01-01

    Here we investigate geochemical characteristics of sediment in different compartments of a karst aquifer and demonstrate that mobile sediments in a karst aquifer can exhibit a wide range of properties affecting their contaminant transport potential. Sediment samples were collected from surface streams, sinkholes, caves, wells, and springs of a karst aquifer (the Barton Springs portion of the Edwards (Balcones Fault Zone) Aquifer, Central Texas) and their mineralogy, grain-size distribution, organic carbon content, and specific surface area analyzed. Statistical analysis of the sediments separated the sampling sites into three distinct groups: (1) streambeds, sinkholes, and small springs; (2) wells; and (3) caves. Sediments from the primary discharge spring were a mix of these three groups. High organic carbon content and increased potential to transport contaminants; the volume of these sediments is likely to increase with continued urbanization of the watershed.

  16. Effect of thin layer caps on cesium contaminated bed sediment remediation

    SciTech Connect

    Omojola, J.O.; Thiobodeaux, L.J.; Novitsky, M.

    1996-10-01

    An alternative to conventional in-situ capping of contaminated bed-sediment is being investigated. The method proposed entails periodically distributing (at 3-month intervals) a thin layer (about 1 cm. in thickness) of silt particles onto the contaminated bed. Lake Swaytoe in Russia, contaminated with Cesium 137, is used for the case study on theoretical model calculations. Due to Cs-137 adsorption on the silt the cap acts as a barrier, reducing the concentration in the porewater, burial of contaminated solids also occurs with subsequent application of layers. Over time, bioturbation enhanced particle transport mixes clean sediment with contaminated sediment thereby reducing the effectiveness of the cap. Particle interchange is modeled over time to predict concentration levels and to adjust the appropriate time interval for putting on a new layer. The results indicate Bed surface porewater Cs-137 concentration can be reduced by over 85% in the first year after four applications of thin layers.

  17. Contributions of contamination and organic enrichment to sediment toxicity near a sewage outfall

    SciTech Connect

    Bay, S.M.; Greenstein, D.J.

    1994-12-31

    Sediment and interstitial water toxicity and contamination were measured at 12 sites near the Los Angeles County Sanitation Districts sewage outfall on the Palos Verdes (Calif.) shelf, a region contaminated with many metal and organic contaminants. The spatial pattern of biological effects (sea urchin growth and fertilization) was compared with chemical concentrations in sediment, interstitial water, and gonad tissue to identify potentially meaningful relationships. Tissue analyses indicated that sediment metals were not bioavailable and therefore unlikely to be a significant factor in the sediment toxicity test responses. Sediment DDTs, PCBs, and PAHs were bioavailable and showed significant correlations with sea urchin growth effects. Interstitial water toxicity was most strongly correlated with measures of organic enrichment (hydrogen sulfide, ammonia) and hydrocarbon contamination. Subsequent dose response experiments confirmed the important role of hydrogen sulfide in interstitial water toxicity but failed to demonstrate an effect of DDE (the most abundant sediment organic contaminant) on growth. Overall, variations in measured sediment characteristics accounted for a relatively small portion of the biological responses.

  18. Passive sampling in contaminated sediment assessment: building consensus to improve decision making.

    PubMed

    Parkerton, Thomas F; Maruya, Keith A

    2014-04-01

    Contaminated sediments pose an ongoing, pervasive, global challenge to environmental managers, because sediments can reflect a legacy of pollution that can impair the beneficial uses of water bodies. A formidable challenge in assessing the risks of contaminated sediments has been the elucidation and measurement of contaminant bioavailability, expressed as the freely dissolved concentration (Cfree ) in interstitial water, which serves as a surrogate measure of the substances' chemical activity. Recent advances in passive sampling methods (PSMs) enable Cfree of sediment-associated contaminants to be quantified at trace levels, thereby overcoming current limitations of predictive models. As a result, PSMs afford the opportunity for a paradigm shift from traditional practice that can effectively reduce uncertainty in risk assessment and bolster confidence in the science used to support management of contaminated sediments. This paper provides a brief overview of the 5 subsequent papers in this series that review literature on PSM use in sediments for both organic and metal(loid) contaminants, outline the technical rationale for using PSMs as a preferred basis for risk assessment over conventional chemical analyses, describe practical considerations for and uncertainties associated with laboratory and field deployment of PSMs, discuss management application of PSMs, including illustrative case studies in which PSMs have been used in decision making, and highlight future research and communication needs. PMID:24142815

  19. Multivariate analysis of heavy metal contamination using river sediment cores of Nankan River, northern Taiwan

    NASA Astrophysics Data System (ADS)

    Lee, An-Sheng; Lu, Wei-Li; Huang, Jyh-Jaan; Chang, Queenie; Wei, Kuo-Yen; Lin, Chin-Jung; Liou, Sofia Ya Hsuan

    2016-04-01

    Through the geology and climate characteristic in Taiwan, generally rivers carry a lot of suspended particles. After these particles settled, they become sediments which are good sorbent for heavy metals in river system. Consequently, sediments can be found recording contamination footprint at low flow energy region, such as estuary. Seven sediment cores were collected along Nankan River, northern Taiwan, which is seriously contaminated by factory, household and agriculture input. Physico-chemical properties of these cores were derived from Itrax-XRF Core Scanner and grain size analysis. In order to interpret these complex data matrices, the multivariate statistical techniques (cluster analysis, factor analysis and discriminant analysis) were introduced to this study. Through the statistical determination, the result indicates four types of sediment. One of them represents contamination event which shows high concentration of Cu, Zn, Pb, Ni and Fe, and low concentration of Si and Zr. Furthermore, three possible contamination sources of this type of sediment were revealed by Factor Analysis. The combination of sediment analysis and multivariate statistical techniques used provides new insights into the contamination depositional history of Nankan River and could be similarly applied to other river systems to determine the scale of anthropogenic contamination.

  20. Catchment-scale environmental controls of sediment-associated contaminant dispersal

    NASA Astrophysics Data System (ADS)

    Macklin, Mark

    2010-05-01

    Globally river sediment associated contaminants, most notably heavy metals, radionuclides, Polychlorinated Biphenyls (PCBs), Organochlorine pesticides (OCs) and phosphorous, constitute one the most significant long-term risks to ecosystems and human health. These can impact both urban and rural areas and, because of their prolonged environmental residence times, are major sources of secondary pollution if contaminated soil and sediment are disturbed by human activity or by natural processes such as water or wind erosion. River catchments are also the primary source of sediment-associated contaminants to the coastal zone, and to the ocean, and an understanding of the factors that control contaminated sediment fluxes and delivery in river systems is essential for effective environmental management and protection. In this paper the catchment-scale controls of sediment-associated contaminant dispersal are reviewed, including climate-related variations in flooding regime, land-use change, channel engineering, restoration and flood defence. Drawing on case studies from metal mining impacted catchments in Bolivia (Río Pilcomayo), Spain (Río Guadiamar), Romania (River Tisa) and the UK (River Swale) some improved methodologies for identifying, tracing, modelling and managing contaminated river sediments are proposed that could have more general application in similarly affected river systems worldwide.

  1. EFFECT OF NITRATE-BASED BIOREMEDIATION ON CONTAMINANT DISTRIBUTION AND SEDIMENT TOXICITY-COLUMN STUDY

    EPA Science Inventory

    A laboratory column study was set up to evaluate changes in contaminant distribution and sediment toxicity following nitrate-based bioremediation and to correlate toxicity reduction with loss of fuel components. Glass columns were packed with sediment from an aquifer that had be...

  2. Microbial Transformation of Polycyclic Aromatic Hydrocarbons in Pristine and Petroleum-Contaminated Sediments

    PubMed Central

    Herbes, S. E.; Schwall, L. R.

    1978-01-01

    To determine rates of microbial transformation of polycyclic aromatic hydrocarbons (PAH) in freshwater sediments, 14C-labeled PAH were incubated with samples from both pristine and petroleum-contaminated streams. Evolved 14CO2 was trapped in KOH, unaltered PAH and polar metabolic intermediate fractions were quantitated after sediment extraction and column chromatography, and bound cellular 14C was measured in sediment residues. Large fractions of 14C were incorporated into microbial cellular material; therefore, measurement of rates of 14CO2 evolution alone would seriously underestimate transformation rates of [14C]naphthalene and [14C]anthracene. PAH compound turnover times in petroleum-contaminated sediment increased from 7.1 h for naphthalene to 400 h for anthracene, 10,000 h for benz(a)anthracene, and more than 30,000 h for benz(a)pyrene. Turnover times in uncontaminated stream sediment were 10 to 400 times greater than in contaminated samples, while absolute rates of PAH transformation (micrograms of PAH per gram of sediment per hour) were 3,000 to 125,000 times greater in contaminated sediment. The data indicate that four- and five-ring PAH compounds, several of which are carcinogenic, may persist even in sediments that have received chronic PAH inputs and that support microbial populations capable of transforming two- and three-ring PAH compounds. PMID:16345270

  3. DETERMINATION OF RATES AND EXTENT OF DECHLORINATION IN PCB-CONTAMINATED SEDIMENTS DURING MONITORED NATURAL RECOVERY

    EPA Science Inventory

    This "Sediment Issue" summarizes investigations carried out by the National Risk Management Research Laboratory (NRMRL) of U.S. EPA to evaluate the long-term recovery of polychlorinated biphenyl (PCB)-contaminated sediments via reductive dechlorination. The magnitude, extent, an...

  4. TREATED WASTEWATER AS A SOURCE OF SEDIMENT CONTAMINATION IN GULF OF MEXICO NEAR-COASTAL AREAS

    EPA Science Inventory

    The primary objective of this baseline survey was to provide some needed perspective on the magnitude of sediment contamination associated with wastewater outfalls discharged to Gulf of Mexico near-coastal areas. The chemical quality and toxicities of whole sediments and pore wa...

  5. Sediment-water distribution of contaminants of emerging concern in a mixed use watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the occurrence and distribution of 15 contaminants of emerging concern (CEC) in stream water and sediments in the Zumbro River watershed in Minnesota and compared these with sub-watershed land uses. Sixty pairs of sediment and water samples were collected across all seasons from...

  6. Uptake and depuration of nonionic organic contaminants from sediment by the oligochaete, Lumbriculus variegatus

    USGS Publications Warehouse

    Ingersoll, C.G.; Brunson, E.L.; Wang, F.N.; Dwyer, J.; Ankley, G.T.; Mount, D.R.; Huckins, J.; Petty, J.; Landrum, P.F.

    2003-01-01

    Uptake of sediment-associated contaminants by the oligochaete Lumbriculus variegatus was evaluated after 1, 3, 7, 14, 28, and 56 d of exposure to a field-collected sediment contaminated with DDT and its metabolites, dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE), or to a field-collected sediment contaminated with polycyclic aromatic hydrocarbons (PAHs). Depuration of contaminants by oligochaetes in a control sediment or in water was also evaluated over a 7-d period after 28 d of exposure to the field-collected sediments. Accumulation of PAHs with a log octanol-water partitioning coefficient (log Kow) 5.6 or DDD and DDE typically exhibited a steady increase from day 1 to about day 14 or 28, followed by a plateau. Therefore, exposures conducted for a minimum of 14 to 28 d better reflected steady-state concentrations for DDT and its metabolites and for PAHs. Depuration rates for DDT and its metabolites and high-Kow PAHs were much higher in organisms held in clean sediment relative to both water-only depuration and model predictions. This suggests that depuration in clean sediment may artificially accelerate depuration of hydrophobic compounds. Comparisons between laboratory-exposed L. variegatus and oligochaetes collected in the field from these sediments indicate that results of laboratory tests can be extrapolated to the field with a reasonable degree of certainty.

  7. Elevated nitrate enriches microbial functional genes for potential bioremediation of complexly contaminated sediments

    PubMed Central

    Xu, Meiying; Zhang, Qin; Xia, Chunyu; Zhong, Yuming; Sun, Guoping; Guo, Jun; Yuan, Tong; Zhou, Jizhong; He, Zhili

    2014-01-01

    Nitrate is an important nutrient and electron acceptor for microorganisms, having a key role in nitrogen (N) cycling and electron transfer in anoxic sediments. High-nitrate inputs into sediments could have a significant effect on N cycling and its associated microbial processes. However, few studies have been focused on the effect of nitrate addition on the functional diversity, composition, structure and dynamics of sediment microbial communities in contaminated aquatic ecosystems with persistent organic pollutants (POPs). Here we analyzed sediment microbial communities from a field-scale in situ bioremediation site, a creek in Pearl River Delta containing a variety of contaminants including polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs), before and after nitrate injection using a comprehensive functional gene array (GeoChip 4.0). Our results showed that the sediment microbial community functional composition and structure were markedly altered, and that functional genes involved in N-, carbon (C)-, sulfur (S)-and phosphorus (P)- cycling processes were highly enriched after nitrate injection, especially those microorganisms with diverse metabolic capabilities, leading to potential in situ bioremediation of the contaminated sediment, such as PBDE and PAH reduction/degradation. This study provides new insights into our understanding of sediment microbial community responses to nitrate addition, suggesting that indigenous microorganisms could be successfully stimulated for in situ bioremediation of POPs in contaminated sediments with nitrate addition. PMID:24671084

  8. PRELIMINARY RESULTS: RELEASE OF METALS FROM ACID-MINE DRAINAGE CONTAMINATED STREAMBED SEDIMENTS UNDER ANOXIC CONDITIONS

    EPA Science Inventory

    Many miles of streams are contaminated with acid-mine drainage (AMD) from abandoned metal mines in the western U.S. Treatment of these streams may include dredging of the existing sediments, with subsequent burial. Burial of previously toxic sediments may result in release of met...

  9. Preliminary Results: Release Of Metals From Acid-Mine Drainage Contaminated Streambed Sediments Under Anaerobic Conditions

    EPA Science Inventory

    Many miles of streams in the western U.S. are contaminated with acid-mine drainage (AMD) from abandoned metal mines. Treatment of these streams may include removal of the existing sediments, with subsequent burial (e.g., in a repository). Burial of previously aerobic sediments ma...

  10. Bench-scale testing of selected remediation alternatives for contaminated sediments.

    PubMed

    Timberlake, D L; Garbaciak, S

    1995-01-01

    The Assessment and Remediation of Contaminated Sediments (ARCS) Program within the U.S. Environmental Protection Agency's Great Lakes National Program Office (GLNPO) contained a component for demonstrating and evaluating sediment remediation technologies. Toward this end, bench-scale tests of solvent extraction, thermal desorption, and wet air oxidation technologies were conducted. Contaminated sediments were tested from the Grand Calumet River, Indiana; Buffalo River, New York; Saginaw River, Michigan; and Ashtabula River, Ohio. The primary contaminants of concern in these sediments were polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs). The solvent extraction tests were conducted with sediments from the Grand Calumet, Buffalo, and Saginaw rivers. The thermal desorption studies were conducted with sediments from the Grand Calumet, Buffalo, and Ashtabula rivers. The wet air oxidation testing was performed with the Grand Calumet River sediment. Raw sediment contaminant concentrations ranged from 0.32-21.9 mg/kg dry mass for PCBs and 2.70-266 mg/kg dry mass for PAHs. PCB removal or destruction efficiencies ranged from approximately 6-99%. PAH removal or destruction efficiencies ranged from 65-99%. Mass balance closures ranged from 40-99% for solids; 59-139% for water; 29-3500% for oil; 16-129% for PCBs; and 69-3170% for PAHs.

  11. Remediation of Hylebos Waterway (Tacoma, WA): A common sense approach to determining contaminated sediment volumes

    SciTech Connect

    Fuglevand, P.; Revelas, G.; Striplin, B.; Striplin, P.

    1995-12-31

    Hylebos Waterway is a three mile long industrial waterway located in Commencement Bay, Washington. A CERCLA program RI/FS, conducted in the mid-1980`s, found that surface sediments (0--2 cm) were contaminated with chlorinated organics, PAHs, and metals. An ongoing pre-remedial design effort, initiated in 1993, is evaluating natural recovery and four sediment confinement options for sediments that exceed programmatic sediment quality objectives: confined aquatic disposal, near-shore disposal, upland disposal, and in-place capping. The first three confinement options require dredging of contaminated sediments which, in turn, requires accurate determination of the three dimensional distribution of contaminated sediments. To place a maximum depth boundary on the sediment sampling approach, isopach maps were created by contouring the difference between the deepest historic dredging depth and current depth along the entire waterway. These isopach maps revealed the pattern of post-industrial sediment deposition in the waterway. For example, in some areas, little or no sediment accumulation had occurred in the navigation channel. Conversely, significant accumulation had occurred along some channel edges and in near-shore areas as the result of deposition, bank sloughing and historic dredging/filling activities. The isopach maps were used to place a lower depth boundary on waterway-wide sediment contamination and to establish the maximum core sampling depth required to reach ``native`` sediments, i.e., those below the deepest historic dredging depth and believed to be uncontaminated. Subsequent geo-technical and chemical analyses of the core samples confirmed the accuracy of the isopach approach. The data generated from this sampling effort are being used to estimate the areas and volumes of subtidal sediments requiring remedial action.

  12. A catchment-integrated approach to determine the importance of secondary sources of contaminated sediment

    NASA Astrophysics Data System (ADS)

    Andres Lopez-Tarazon, Jose; Byrne, Patrick; Mullan, Donal; Smith, Hugh

    2015-04-01

    Water pollution has been identified as one of the most important environmental challenges of the early 21st Century. The Water Framework Directive (WFD) (2008/105/EC) explicitly recognises the risk to water resources posed by sediment-associated contaminants in European river basins. The potential impacts on water supply and the biodiversity of aquatic ecosystems from sediment and associated contaminants may be further exacerbated by climate change pressures on water resources, as highlighted in the 2009 EU White Paper "Adapting to climate change: Towards a European framework for action" (SEC(2009) 386, 387, 388). Despite these concerns, the role of floodplains and other storage areas as secondary sources of contaminated sediment (i.e. metals) in river basins affected by historic industrial or mining pollution has been largely overlooked. Thereby, besides the sediment which is transported by the river, secondary sources of contaminants represent a credible threat to achieving EU water quality targets set by the WFD. This project addresses this issue by developing a catchment-based approach looking at metal geochemistry from source to sink (i.e., from sediment generation at slopes, passing through sediment transported by the river system, to sediment deposition at the storage areas to the outlet) and develop a geochemical model to predict the chemical aspects of metals transport and transformation. This approach will allow us to quantify (i) the sediment fluxes and associated contaminants flowing through the river, (ii) the storage areas contributions to downstream contaminated sediment fluxes, (ii) the timescales for the storage and removal of contaminated sediment in the sinks, and (iv) the transformation and bioavailability of the pollutants (i.e. metals) along the basin. Both physical and chemical aspects of metal transport will be considered by looking at metal geochemistry, mobility and bioavailability, hence producing information on chemical metal transport

  13. Sediment contamination and associates laboratory-measured bioaccumulation in New York/New Jersey waterways

    SciTech Connect

    Rosman, L.B.; Barrows, E.S.

    1995-12-31

    Sediments from 10 New York/New Jersey waterways within the Hudson-Raritan Estuary and Long Island Sound were collected to depths representative of dredging activity. Composited core sediments representing each waterway were analyzed for metals, PAHs, PCBs, and pesticides. To assess bioaccumulation, sand worms (Nereis virens) and blunt-nose clams (Macoma nasuta) were exposed for 28 days to sediment composites and to New York Bight sediment. Tissues were analyzed for the same constituents as the sediment samples. The results highlight the range and magnitude of sediment contamination in NY/NJ waterways. Concentrations of some metals in sediments, compared with NY Bight sediment, were at least 10 times higher. Total PAHs reached 30,000 {micro}g/kg (dry weight). The sum of DDT, DDD, and DDE, the dominant pesticides, exceeded 3,000{micro}g/kg (dry weight). Total PCBs approached 3,000 {micro}g/kg (dry weight). Tissues exposed to sediments from several waterways bioaccumulated organic compounds at concentrations 10 times greater than those exposed to New York Bight sediments. Metals were bioaccumulated to a lesser degree. The presence and extent of bioaccumulated contaminants, along with sediment chemistry and benthic toxicity, create a profile characterizing each waterway.

  14. Radioactive contamination of the Balchug (Upper Yenisey) floodplain, Russia in relation to sedimentation processes and geomorphology.

    PubMed

    Linnik, V G; Brown, J E; Dowdall, M; Potapov, V N; Surkov, V V; Korobova, E M; Volosov, A G; Vakulovsky, S M; Tertyshnik, E G

    2005-03-01

    The radioactive contamination of a riverine floodplain, heavily influenced by discharges from Krasnoyarsk-26, has been studied with respect to sedimentation processes and the geomorphology of the Upper Yenisey floodplain. The study was effected by implementation of a regime of in situ observations and measurements, sampling, and the interpretation of satellite images. The results of the study indicate that on the Balchug Bypass Floodplain, radionuclide contamination is primarily influenced by the thickness of the deposited sediments, and the area can be considered as two depositional environments. The Balchug floodplain area was contaminated due to sedimentation of radionuclide-contaminated alluvium, whose depositional regime significantly changed after the construction of a hydroelectric power station in 1967. Contamination levels are lower on the upstream part of the floodplain where sediment depth is less than 0.2-0.3 m, and this contamination started to accumulate in 1967, while the downstream part of the floodplain, exhibiting deeper deposits, displays higher levels of radionuclide contamination because radionuclides began to deposit here in 1958 when the Krasnoyarsk-26 Mining and Chemical Combine (KMCC) commenced operation. Radionuclide contamination of the floodplain is also related to the elevation of the floodplain, higher regions of the floodplain typically having lower contamination than low-lying areas, which tend to be frequently inundated with sediments being deposited during such inundations. Local relief, its orientation, and vegetation cover have also combined to form sediment traps with significantly higher radionuclide contamination. Lithological analysis combined with radiometric assay indicates a total 137Cs floodplain inventory of 33.7 GBq.

  15. SEDIMENTS: A RESERVOIR OF HISTORIC CONTAMINATION OF THE DETROIT RIVER

    EPA Science Inventory

    Presentation to a citizen's environment alliance regarding contamination of the Detroit River. Types and amounts of contaminants were outlined and major pollution sources were identified. Outline for remediation plan was presented. However, before remediation can be done, upstre...

  16. Polychaete burrows harbour distinct microbial communities in oil-contaminated coastal sediments.

    PubMed

    Taylor, Joe D; Cunliffe, Michael

    2015-08-01

    Previous studies have shown that the bioturbating polychaete Hediste (Nereis) diversicolor can affect the composition of bacterial communities in oil-contaminated sediments, but have not considered diversity specifically within bioturbator burrows or the impact on microbial eukaryotes. We tested the hypothesis that H. diversicolor burrows harbour different eukaryotic and bacterial communities compared with un-bioturbated sediment, and that bioturbation stimulates oil degradation. Oil-contaminated sediment was incubated with or without H. diversicolor for 30 days, after which sediment un-affected by H. diversicolor and burrow DNA/RNA samples were analysed using quantitative reverse transcription PCR (Q-RT-PCR) and high-throughput sequencing. Fungi dominated both burrow and un-bioturbated sediment sequence libraries; however, there was significant enrichment of bacterivorous protists and nematodes in the burrows. There were also significant differences between the bacterial communities in burrows compared with un-bioturbated sediment. Increased activity and relative abundance of aerobic hydrocarbon-degrading bacteria in the burrows coincided with the significant reduction in hydrocarbon concentration in the bioturbated sediment. This study represents the first detailed assessment of the effect of bioturbation on total microbial communities in oil-contaminated sediments. In addition, it further shows that bioturbation is a significant factor in determining microbial diversity within polluted sediments and plays an important role in stimulating bioremediation.

  17. Limited Field Investigation Report for Uranium Contamination in the 300 Area, 300-FF-5 Operable Unit, Hanford Site, Washington

    SciTech Connect

    Williams, Bruce A.; Brown, Christopher F.; Um, Wooyong; Nimmons, Michael J.; Peterson, Robert E.; Bjornstad, Bruce N.; Lanigan, David C.; Serne, R. Jeffrey; Spane, Frank A.; Rockhold, Mark L.

    2007-11-01

    Four new CERCLA groundwater monitoring wells were installed in the 300-FF-5 Operable Unit in FY 2006 to fulfill commitments for well installations proposed in the Hanford Federal Facility Agreement and Consent Order Milestone M-24-57. Wells were installed to collect data to determine the distribution of process uranium and other contaminants of potential concern in groundwater. These data will also support uranium contaminant transport simulations and the wells will supplement the water quality monitoring network for the 300-FF-5 OU. This report supplies the information obtained during drilling, characterization, and installation of the new groundwater monitoring wells. This document also provides a compilation of hydrogeologic, geochemical, and well construction information obtained during drilling, well development, and sample collection/analysis activities.

  18. In situ vitrification of a mixed-waste contaminated soil site: The 116-B-6A crib at Hanford

    SciTech Connect

    Luey, J.; Koegler, S.S.; Kuhn, W.L.; Lowery, P.S.; Winkelman, R.G.

    1992-09-01

    The first large-scale mixed-waste test of in situ vitrification (ISV) has been completed. The large-scale test was conducted at an actual contaminated soil site, the 116-B-6A crib, on the Department of Energy's Hanford Site. The large-scale test was a demonstration of the ISV technology and not an interim action for the 116-B-6A crib. This demonstration has provided technical data to evaluate the ISV process for its potential in the final disposition of mixed-waste contaminated soil sites at Hanford. Because of the test's successful completion. technical data on the vitrified soil are available on how well the process incorporates transuranics and heavy metals into the waste form. how well the form resists leaching of transuranics and heavy metals. how well the process handles sites with high combustible loadings, and the important site parameters which may affect the achievable process depth. This report describes the 116-B-6A crib site, the objectives of the ISV demonstration, the results in terms of the objectives, and the overall process performance.

  19. Contaminants in surface water and sediments near the Tynagh silver mine site, County Galway, Ireland.

    PubMed

    O'Neill, A; Phillips, D H; Bowen, J; Sen Gupta, B

    2015-04-15

    A former silver mine in Tynagh, Co. Galway, Ireland is one of the most contaminated mine sites in Europe with maximum concentrations of Zn, As, Pb, Mn, Ni, Cu, and Cd far exceeding guideline values for water and sediment. The aims of this research were to 1) further assess the contamination, particularly metals, in surface water and sediment around the site, and 2) determine if the contamination has increased 10 years after the Environmental Protection Agency Ireland (EPAI) identified off-site contamination. Site pH is alkaline to neutral because CaCO3-rich sediment and rock material buffer the exposed acid generating sulphide-rich ore. When this study was compared to the previous EPAI study conducted 10 years earlier, it appeared that further weathering of exposed surface sediment had increased concentrations of As and other potentially toxic elements. Water samples from the tailings ponds and adjacent Barnacullia Stream had concentrations of Al, Cd, Mn, Zn and Pb above guideline values. Lead and Zn concentrations from the tailings pond sediment were 16 and 5 times higher, respectively, than concentrations reported 10 years earlier. Pb and Zn levels in most sediment samples exceeded the Expert Group (EGS) guidelines of 1000 and 5000 mg/kg, respectively. Arsenic concentrations were as high as 6238 mg/kg in the tailings ponds sediment, which is 62 and 862 times greater than the EGS and Canadian Soil Quality Guidelines (CSQG), respectively. Cadmium, Cu, Fe, Mn, Pb and Zn concentrations in water and sediment were above guideline values downstream of the site. Additionally, Fe, Mn and organic matter (OM) were strongly correlated and correlated to Zn, Pb, As, Cd, Cu and Ni in stream sediment. Therefore, the nearby Barnacullia Stream is also a significant pathway for contaminant transport to downstream areas. Further rehabilitation of the site may decrease the contamination around the area. PMID:25634731

  20. Uptake pathway for Ag bioaccumulation in three benthic invertebrates exposed to contaminated sediments

    USGS Publications Warehouse

    Yoo, H.; Lee, J.-S.; Lee, B.-G.; Lee, I.T.; Schlekat, C.E.; Koh, C.-H.; Luoma, S.N.

    2004-01-01

    We exposed 3 benthic invertebrates, the clam Macoma balthica, the polychaete Neanthes arenaceodentata and the amphipod Leptocheirus plumulosus, to Ag-contaminated sediments to evaluate the relative importance of various uptake routes (sediments, porewater or overlying water, and supplementary food) for Ag bioaccumulation. Silver bioaccumulation was evaluated at 4 levels of sediment Ag (0.1, 0,3, 1,2 and 3.3 ??mol Ag g-1) and 2 levels of acid-volatile sulfide (AVS), <0.5 or ???40 ??mol g-1, and compared among food treatments with or without Ag contamination, or with different food rations. L. plumulosus were incubated for 35 d in the Ag-contaminated sediments after 3 mo of Ag-sediment equilibration, and M. balthica and N. arenaceodentata for 19 d after 5 mo equilibration. Ag bioaccumulation in the 3 organisms was significantly correlated with 1N HCl-extractable Ag concentrations (Ag-SEM: simultaneously extracted Ag with AVS) in sediments. The Ag concentrations in porewater and overlying water were greatest in the sediments with least AVS, consistent with previous studies. Nevertheless, the amphipod and clam exposed to oxic sediments (<0.5 ??mol AVS g-1) accumulated amounts of Ag similar to those accumulated by organisms exposed to anoxic sediments (???40 ??mol AVS g-1), when Ag-SEM levels were comparable. The dissolved Ag source was important for bioaccumulation in the polychaete N. arenaceodentata. Amphipods fed Ag-contaminated food contained ???1.8-fold more tissue Ag concentrations than those fed uncontaminated food. As suggested in kinetic (DYMBAM) modeling studies, ingestion of contaminated sediments and food were the principle routes of Ag bioaccumulation by the benthic invertebrates during chronic exposure, but the relative importance of each uptake route differed among species.

  1. Remote Methodology used at B Plant Hanford to Map High Radiation and Contamination Fields and Document Remaining Hazards

    SciTech Connect

    SIMMONS, F.M.

    2000-01-01

    A remote radiation mapping system using the Gammacam{trademark} (AIL Systems Inc. Trademark) with real-time response was used in deactivating the B Plant at Hanford to produce digitized images showing actual radiation fields and dose rates. Deployment of this technology has significantly reduced labor requirements, decreased personnel exposure, and increased the accuracy of the measurements. Personnel entries into the high radiation/contamination areas was minimized for a dose savings of 30 Rem (.3 Seivert) and a cost savings of $640K. In addition, the data gathered was utilized along with historical information to estimate the amount of remaining hazardous waste in the process cells. The B Plant facility is a canyon facility containing 40 process cells which were used to separate cesium and strontium from high level waste. The cells and vessels are contaminated with chemicals used in the separation and purification processes. Most of the contaminants have been removed but the residual contamination from spills in the cells and heels in the tanks contribute to the localized high radioactivity. The Gammacam{trademark} system consists of a high density terbium-activated scintillating glass detector coupled with a digitized video camera. Composite images generated by the system are presented in pseudo color over a black and white image. Exposure times can be set from 10 milliseconds to 1 hour depending on the field intensity. This information coupled with process knowledge is then used to document the hazardous waste remaining in each cell. Additional uses for this radiation mapping system would be in support of facilities stabilization and deactivation activities at Hanford or other DOE sites. The system is currently scheduled for installation and mapping of the U Plant in 1999. This system is unique due to its portability and its suitability for use in high dose rate areas.

  2. Avoidance response of the estuarine amphipod Eohaustorius estuarius to polycyclic aromatic hydrocarbon-contaminated, field-collected sediments

    SciTech Connect

    Kravitz, M.J. . Office of Water); Lamberson, J.O.; Ferraro, S.P.; Swartz, R.C.; Boese, B.L.; Specht, D.T. )

    1999-06-01

    Amphipods (Eohaustorius estuarius) were placed in two-chamber containers with different combinations of three contaminated sediments and a control sediment, and their distribution was determined after 2 or 3 d. Amphipods avoided the sediment with the highest PAH contamination and one of two sediments with moderate PAH concentrations. In the moderately contaminated sediment avoided by amphipods, the (avoidance) response was more sensitive than mortality as a biological indicator of unacceptable sediment contamination. The avoidance response in this case likely represents an early indication of potential mortality from sediment exposure. Population levels of amphipods in moderately to heavily PAH-contaminated sediments may be influenced by a combination of avoidance behavior and toxicity/lethality.

  3. SEDIMENT CHEMICAL CONTAMINATION AND TOXICITY ASSOCIATED WITH A COASTAL GOLF COURSE COMPLEX.

    EPA Science Inventory

    The increasing density of golf courses represents a potential source of sediment contamination to nearby coastal areas, the chemical and biological magnitude of which is almost unknown. The objective of this study was to determine the concentrations of contaminants and toxicities...

  4. MANAGING ARSENIC CONTAMINATED SOIL, SEDIMENT, AND INDUSTRIAL WASTE WITH SOLIDIFICATION/STABILIZATION TREATMENT

    EPA Science Inventory

    Arsenic contamination of soil, sediment and groundwater is a widespread problem in certain areas and has caused great public concern due to increased awareness of the health risks. Often the contamination is naturally occurring, but it can also be a result of waste generated from...

  5. ENGINEERING ISSUE: TECHNOLOGY ALTERNATIVES FOR THE REMEDIATION OF PCB-CONTAMINATED SOIL AND SEDIMENT

    EPA Science Inventory

    Because of the increased need for Superfund decision-makers to have a working knowledge of the remedial capabilities available to treat soil and sediment contaminated with polychlorinated biphenyls (PCBs), the Superfund Engineering Forum has identified remediation of PCB-contamin...

  6. A method for estimation of historic contaminant loads using dated sediment cores

    EPA Science Inventory

    Dated sediment cores were used to assess the history of contaminant loads. The contaminant selected must be one that is not significantly remobilized by post depositional processes such as diagenesis. In addition, the core must be from an area with a high deposition rate and litt...

  7. Identifying the sources of subsurface contamination at the Hanford Site in Washington using high-precision uranium isotopic measurements.

    PubMed

    Christensen, John N; Dresel, P Evan; Conrad, Mark E; Maher, Kate; DePaolo, Donald J

    2004-06-15

    In the mid-1990s, a groundwater plume of uranium (U) was detected in monitoring wells in the B-BX-BY Waste Management Area at the Hanford Site in Washington. This area has been used since the late 1940s to store high-level radioactive waste and other products of U fuel-rod processing. Using multiple-collector ICP source magnetic sector mass spectrometry, high-precision uranium isotopic analyses were conducted of samples of vadose zone contamination and of groundwater. The isotope ratios 236U/238U, 234U/238U, and 238U/235U are used to distinguish contaminant sources. On the basis of the isotopic data, the source of the groundwater contamination appears to be related to a 1951 overflow event at tank BX-102 that spilled high-level U waste into the vadose zone. The U isotopic variation of the groundwater plume is a result of mixing between contaminant U from this spill and natural background U. Vadose zone U contamination at tank B-110 likely predates the recorded tank leak and can be ruled out as a significant source of groundwater contamination, based on the U isotopic composition. The locus of vadose zone contamination is displaced from the initial locus of groundwater contamination, indicating that lateral migration in the vadose zone was at least 8 times greater than vertical migration. The time evolution of the groundwater plume suggests an average U migration rate of approximately 0.7-0.8 m/day showing slight retardation relative to a groundwater flow of approximately 1 m/day.

  8. PILOT LAND TREATMENT OF PAH-CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Hazardous dredged sediments are typically placed in confined disposal facilities (CDFs) which are designed to dewater and contain but not treat sediments. Since navigational dredging in the U.S. is quickly filling many CDFs, these facilities have little available capacity for ne...

  9. Recent advances in the use of estuarine meiobenthos to assess contaminated sediment effects in multi-species whole sediment microcosms

    SciTech Connect

    Chandler, G.T.; Coull, B.C.; Schizas, N.V.; Donelan, T.L.

    1995-12-31

    Many marine meiobenthic taxa (i.e. invertebrates passing a 1-mm sieve but retaining on a 0.063 mm sieve) are ideal for ``whole-sediment`` and porewater bioassay of sedimented pollutants. Annual production of meiobenthos is 5--10 times that of the more commonly studied macrobenthos, and > 95% of all meiobenthos live in the oxic zone of muddy sediments at densities of 4--12 million per M{sup 2}. Most spend their entire lifecycles, burrowing freely and feeding on/within the sediment:porewater matrix, many taxa undergo 10--14 generations per year, most larval/juvenile stages are benthic, and many have easily quantifiable reproductive output. Furthermore, many meiobenthic taxa can be cultured indefinitely over multiple life-cycles within simple sediment microcosms consisting of sealed whole-sediment cores collected intact from intertidal mudflats. The authors describe several recent technical developments exploiting meiofaunal sediment culture for rapid contaminated sediment bioassays of toxicant effects on survival, reproduction and population growth of meiobenthic taxa in whole-sediment microcosms. Currently meiobenthic copepods, nematodes, foraminifers and polychaetes are being continuously cultured to study these parameters under exposure to model sediment-associated toxicants (e.g. cadmium). Bioassays are run for 21-d under flowing seawater. With this approach, fertile benthic copepods (e.g. Amphiascus tenuiremis) can be added to core microcosms to assess survival and growth of a fixed population cohort. All other meiobenthic taxa are enumerated relative to controls and evaluated for toxicant effects on higher order community-level endpoints. This approach exploits meiobenthos` high abundance and rapid reproductive rates to yield on a micro scale better endpoints than much larger sediment mesocosms targeted at macrofaunal endpoints.

  10. Bioavailability of sediment-bound contaminants and the importance of digestive history

    SciTech Connect

    Weston, D.P.; Penry, D.L.; Baker, J.E. |

    1994-12-31

    It is generally recognized that animals will optimize their gain of energy and nutrients from a given food source, and acclimation processes operating over a period of days are important to this optimization. This research investigates whether the bioavailability of sediment-bound contaminants varies as a function of acclimation period to a given sediment type. In other words, would the bioavailability of a sediment-associated contaminant be determined by whether the animal had in the recent past fed on a sediment with similar physical characteristics? If this dependence did exist, it could be of considerable importance to sediment toxicity testing and toxicokinetic modeling. The polychaete, Abarenicola Pacifica, was exposed to sediments spiked with phenanthrene and benzo(a)pyrene. Bioavailability of these contaminants was determined both by assimilation efficiency and body burden. Preliminary data suggest that PAH bioavailability is not a function of digestive history, i.e., the rate or efficiency of PAH uptake was not dependent upon whether the animal had spent a pre-exposure period in sediment physically similar to the contaminated material. This observation would support either: (1) minimal importance of digestion as a route of PAH uptake, or (2) passive uptake of PAH across the gut wall with little involvement of enzymatic digestion.

  11. Bioavailability of sediment-bound contaminants and the importance of digestive history

    SciTech Connect

    Weston, D.P.; Penry, D.L.; Baker, J.E.

    1995-12-31

    It is generally recognized that animals will optimize their gain of energy and nutrients from a given food source, and acclimation processes operating over a period of days are important to this optimization. This research investigates whether the bioavailability of sediment-bound contaminants varies as a function of acclimation period to a given sediment type. In other words, would the bioavailability of a sediment-associated contaminant be determined by whether the animal had, in the recent past, fed on a sediment with similar physical characteristics? If this dependence did exist, it could be of considerable importance to sediment toxicity testing and toxico-kinetic modeling. The polychaete, Abarenicola pacifica, was exposed to sediments spiked with phenanthrene and benzo(a)pyrene. Bioavailability of these contaminants was determined both by assimilation efficiency and body burden. The data suggest that PAH bioavailability is not a function of digestive history, i.e., the rate or efficiency of PAH uptake was not dependent upon whether the animal had spent a pre-exposure period in sediment physically similar to the contaminated material. This observation would support either: (1) minimal importance of digestion as a route of PAH uptake, or (2) passive uptake of PAH across the gut wall with little involvement of enzymatic digestion.

  12. Green remediation and recycling of contaminated sediment by waste-incorporated stabilization/solidification.

    PubMed

    Wang, Lei; Tsang, Daniel C W; Poon, Chi-Sun

    2015-03-01

    Navigational/environmental dredging of contaminated sediment conventionally requires contained marine disposal and continuous monitoring. This study proposed a green remediation approach to treat and recycle the contaminated sediment by means of stabilization/solidification enhanced by the addition of selected solid wastes. With an increasing amount of contaminated sediment (20-70%), the 28-d compressive strength of sediment blocks decreased from greater than 10MPa to slightly above 1MPa. For augmenting the cement hydration, coal fly ash was more effective than lime and ground seashells, especially at low sediment content. The microscopic and spectroscopic analyses showed varying amounts of hydration products (primarily calcium hydroxide and calcium silicate hydrate) in the presence of coal fly ash, signifying the influence of pozzolanic reaction. To facilitate the waste utilization, cullet from beverage glass bottles and bottom ashes from coal combustion and waste incineration were found suitable to substitute coarse aggregate at 33% replacement ratio, beyond which the compressive strength decreased accordingly. The mercury intrusion porosimetry analysis indicated that the increase in the total pore area and average pore diameter were linearly correlated with the decrease of compressive strength due to waste replacement. All the sediment blocks complied with the acceptance criteria for reuse in terms of metal leachability. These results suggest that, with an appropriate mixture design, contaminated sediment and waste materials are useful resources for producing non-load-bearing masonry units or fill materials for construction uses.

  13. Sediment contamination and faunal communities in two subwatersheds of Mona Lake, Michigan.

    PubMed

    Cooper, Matthew J; Rediske, Richard R; Uzarski, Donald G; Burton, Thomas M

    2009-01-01

    Urbanization of watersheds can impose multiple stressors on stream, wetland, and lake ecosystems. Sediment contamination, alterations to the natural hydrologic regime, and nutrient loading are examples of these stressors which often occur simultaneously. As a consequence, restoration is challenged by the multi-stressor reality of most urban watersheds. The goal of this study was to compare two watersheds in western Michigan, both with substantial urban development, but with different levels of sediment contamination resulting from historic industrial activities, to determine the effects of contamination on invertebrate and fish community structure. The study included multiple sites on both streams, two wetlands adjacent to each stream, and the embayments where each stream emptied into Mona Lake. We compared a suite of abiotic parameters including sediment contamination, sediment toxicity, and water column chemical/physical conditions as well as fish and invertebrate community structure. Sediment contaminants, including heavy metals and polycyclic aromatic hydrocarbons, were found in higher concentrations and survival of test organisms in toxicity bioassays was reduced in the more industrialized watershed. Fewer insect taxa, especially the sensitive Ephemeroptera, Plecoptera, and Trichoptera, were found in the more industrialized system. Fish taxa richness and catch per unit effort were reduced in the wetlands of the more industrialized watershed as well and both invertebrate and fish index of biotic integrity scores were also lower in the more industrialized system. Our study demonstrates that contamination due to historic industrial activities can have substantial and lasting effects on biotic communities of multiple habitat types well downstream of where the activities occurred.

  14. Hanford Tank 241-C-103 Residual Waste Contaminant Release Models and Supporting Data

    SciTech Connect

    Cantrell, Kirk J.; Krupka, Kenneth M.; Deutsch, William J.; Lindberg, Michael J.; Schaef, Herbert T.; Geiszler, Keith N.; Arey, Bruce W.

    2008-01-15

    This report tabulates data generated by laboratory characterization and testing of three samples collected from tank C-103. The data presented here will form the basis for a release model that will be developed for tank C-103. These release models are being developed to support the tank risk assessments performed by CH2M HILL Hanford Group, Inc. for DOE.

  15. Enhanced biodegradation of hydrocarbon-contaminated sediments using microbial fuel cells.

    PubMed

    Morris, Jeffrey M; Jin, Song

    2012-04-30

    A sediment microbial fuel cell (MFC) was tested to determine if electron transfer from the anaerobic zone of contaminated sediments to the overlying aerobic water could facilitate an enhanced and aerobic equivalent degradation of total petroleum hydrocarbons (TPH). Results indicate that voltages as high as 190 mV (2162 mW/m(3)) were achieved in a sediment MFC with an anode buried in sediments containing TPH concentrations at approximately 16,000 mg kg(-1). Additionally, after approximately 66 days, the TPH degradation rates were 2% and 24% in the open-circuit control sediment MFC and active sediment MFC, respectively. Therefore, it appears that applying MFC technology to contaminated sediments enhances natural biodegradation by nearly 12 fold. Additionally, a novel sediment MFC was designed to provide a cost-effective method of passive oxidation or indirect aerobic degradation of contaminants in an otherwise anaerobic environment. In addition, the use of a wicking air cathode in this study maintained dissolved oxygen concentrations 1-2 mg l(-1) higher than submerged cathodes, demonstrating that this technology can be applied to environments with either aerobic or anaerobic overlying water and an anaerobic matrix, such as shallow lagoon, ponds, and marshes, and groundwater.

  16. Effects of sediment contamination by artisanal gold mining on Chironomus riparius in Mabubi River, Tanzania

    NASA Astrophysics Data System (ADS)

    Chibunda, R. T.; Pereka, A. E.; Tungaraza, C.

    The contamination of sediments by mercury from in artisanal gold mining has been only assessed through bulk chemical analysis and subsequent comparison with reference values from uncontaminated areas. However, measurement of contaminant levels alone has a limited ability to predict adverse effects on living resources. This study investigated the possible effects of contamination of sediments in Mabubi River by mercury drained from Mugusu artisanal gold mine on the survival, growth and emergency of the benthic midge Chironomus riparius. Sediments collected downstream from the Mugusu Mine impaired growth and delayed emergence of the midges but did not impair survival. Mean dry body weight of larvae from sediments collected 3 km down stream (1012 μg) was significantly lower than those from the control sediment ( p < 0.05). Compared to the control sediment, the emergence of the midges from sediments collected up to 6 km downstream of the mining activity were delayed for four days. In conclusion, chemistry and ecotoxicity results from this study suggest that sediments collected in the Mabubi River downstream of the Mugusu mine adversely affect C. riparius and probably other fauna and as such present a considerable local environmental risk.

  17. Molecular tools to understand the bioremediation effect of plants and earthworms on contaminated marine sediments.

    PubMed

    Moreno, Beatriz; Cañizares, Rosa; Macci, Cristina; Doni, Serena; Masciandaro, Grazia; Benitez, Emilio

    2015-12-30

    A meso-scale pilot plant was set up to test the efficiency of a bioremediation scheme applied to marine sediments contaminated by heavy metals and hydrocarbons. The experiment was implemented for three years in two stages using two remediation agents: plants (Paspalum vaginatum and Tamarix gallica) and earthworms (Eisenia fetida). DNA and RNA-based methodologies were applied to elucidate the dynamics of the bacterial population and were related to improving biological and chemical conditions of the sediments. Bioremediation strategies were successful in removing pollutants from the contaminated sediments and specialization within the bacterial community related to the type of contamination present was detected in the different stages of the process. The highest response of Gram-positive PAH-degraders to the contamination was detected at the beginning and after the first stage of the experiment, corresponding to the uppermost values of degradation.

  18. Accumulation of polychlorinated organic contaminants from sediment by three benthic marine species

    SciTech Connect

    Pruell, R.J.; Rubinstein, N.I.; Taplin, B.K.; LiVolsi, J.A.; Bowen, R.D.

    1993-01-01

    A laboratory experiment was conducted to measure the accumulation of selected polychlorinated compounds by marine benthos exposed to environmentally contaminated sediment. Sandworms (Nereis virens), clams (Macoma nasuta), and grass shrimp (Palaemonetes pugio) were exposed to sediment collected from the Passaic River, New Jersey. All three species accumulated 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF) and polychlorinated biphenyls (PCBs) from the sediment. In addition, a recently identified sulfur containing analog of tetrachlorinated dibenzofurans. The objectives of the study were to determine the relative bioavailability of 2,3,7,8-TCDD, 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF) and selected PCB congeners from bottom sediments as well as to examine the relationship between contaminant concentrations in sediments and biota.

  19. Influence of a Brazilian sewage outfall on the toxicity and contamination of adjacent sediments

    USGS Publications Warehouse

    Abessa, D.M.S.; Carr, R.S.; Rachid, B.R.F.; Sousa, E.C.P.M.; Hortelani, M.A.; Sarkis, J.E.

    2005-01-01

    The submarine sewage outfall of Santos (SSOS) is situated in the Santos Bay (São Paulo, Brazil) and is potentially a significant source of contaminants to the adjacent marine ecosystem. The present study aimed to assess the influence of SSOS on the sediment toxicity and contamination at Santos Bay. At the disposal site, sediments tended to be finer, organically richer and exhibited higher levels of surfactants and metals, sometimes exceeding the “Threshold Effect Level” values. The SSOS influence was more evident toward the East, where the sediments exhibited higher levels of TOC, total S and metals during the summer 2000 sampling campaign. Sediment toxicity to amphipods was consistently detected in four of the five stations studied. Amphipod survival tended to correlate negatively to Hg, total N and % mud. This work provides evidence that the SSOS discharge affects the quality of sediments from Santos Bay, and that control procedures are warranted.

  20. Geochemical and microbiological responses to oxidant introduction into reduced subsurface sediment from the Hanford 300 Area, Washington.

    PubMed

    Percak-Dennett, Elizabeth M; Roden, Eric E

    2014-08-19

    Pliocene-aged reduced lacustrine sediment from below a subsurface redox transition zone at the 300 Area of the Hanford site (southeastern Washington) was used in a study of the geochemical response to introduction of oxygen or nitrate in the presence or absence of microbial activity. The sediments contained large quantities of reduced Fe in the form of Fe(II)-bearing phyllosilicates, together with smaller quantities of siderite and pyrite. A loss of ca. 50% of 0.5 M HCl-extractable Fe(II) [5-10 mmol Fe(II) L(-1)] and detectable generation of sulfate (ca. 0.2 mM, equivalent to 10% of the reduced inorganic sulfur pool) occurred in sterile aerobic reactors. In contrast, no systematic loss of Fe(II) or production of sulfate was observed in any of the other oxidant-amended sediment suspensions. Detectable Fe(II) accumulation and sulfate consumption occurred in non-sterile oxidant-free reactors. Together, these results indicate the potential for heterotrophic carbon metabolism in the reduced sediments, consistent with the proliferation of known heterotrophic taxa (e.g., Pseudomonadaceae, Burkholderiaceae, and Clostridiaceae) inferred from 16S rRNA gene pyrosequencing. Microbial carbon oxidation by heterotrophic communities is likely to play an important role in maintaining the redox boundary in situ, i.e., by modulating the impact of downward oxidant transport on Fe/S redox speciation. Diffusion-reaction simulations of oxygen and nitrate consumption coupled to solid-phase organic carbon oxidation indicate that heterotrophic consumption of oxidants could maintain the redox boundary at its current position over millennial time scales. PMID:25014732

  1. Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments

    SciTech Connect

    Stoliker, Deborah L.; Liu, Chongxuan; Kent, Douglas B.; Zachara, John M.

    2013-02-12

    Rates of contaminant U(VI) release from individual size fractions of a composite sediment from the seasonally saturated lower vadose zone of the Hanford 300-Area were examined in flow-through batch reactors to maintain quasi-constant chemical conditions. Variability in equilibrium adsorption among the various size fractions was determined in static batch reactors and analyzed using the surface complexation modeling approach. The estimated stoichiometric coefficients of U(VI) surface complexation reactions with respect to pH and carbonate concentrations varied with size fractions. This source of variability significantly increased the uncertainty in U(VI) conditional equilibrium constants over that estimated from experimental errors alone. A minimum difference between conditional equilibrium constants was established in order to evaluate statistically significant differences between sediment adsorption properties. A set of equilibrium and kinetic expressions for cation exchange, calcite dissolution, aerobic respiration, and silica dissolution were incorporated in a reaction-rate model to describe the temporal evolution of solute concentrations observed during the flow-through batch experiments. Parameters in the reaction-rate model, calibrated using experimental data for select size fractions, predicted the changes in solute concentrations for the bulk, <2 mm, sediment sample. Kinetic U(VI) desorption was well described using a multi-rate surface complexation model with an assumed lognormal distribution for the rate constants. The estimated mean and standard deviation were the same for all < 2mm size fractions, but differed in the 2-8mm size fraction. Micropore volumes in the varied size fractions were also similar as assessed using t-plots to analyze N2 desorption data. These findings provide further support for the link between microporosity and particle-scale mass transfer rates controlling kinetic U(VI) adsorption/desorption and for the utility of N2 desorption

  2. Chromium Isotopic Fractionation During Biogeochemical Cr (IV) Reduction in Hanford Sediment Column Experiments with Native Aquifer Microbial Communities

    NASA Astrophysics Data System (ADS)

    Qin, L.; Christensen, J. N.; Brown, S. T.; Yang, L.; Conrad, M. E.; Sonnenthal, E. L.; Beller, H. R.

    2010-12-01

    Hexavalent Chromium contamination in groundwater within the DOE complex, including the Hanford 100D and 100H sites has been a long-standing issue. It has been established that certain bacteria (including denitrifying and sulfate-reducing bacteria) harbor enzymes that catalyze Cr(VI) reduction to relatively nontoxic Cr(III). Microbial reduction of Cr(VI) also occurs indirectly by products of microbial respiration, such as sulfide and Fe(II). Chromium isotopes can be fractionated during Cr(VI) reduction and provides a potential basis for characterizing and discriminating between different microbial metabolic and geochemical pathways associated with Cr(VI) reductive immobilization. Addition of electron donor to contaminated groundwater systems to create conditions favorable for reductive metal immobilization has become a widely utilized remediation practice. We conducted a series of small-scale column experiments with homogenized material from the Hanford 100H aquifer to examine the effects of differing electron acceptors on local microbial communities. All columns have a continuous inflow of solutions with constant concentrations of Cr(VI), lactate (electron donor), and the appropriate electron acceptor (e.g. nitrate or sulfate). The Cr isotopic composition in the effluent was measured using a 50-54 double-spike technique and a Triton TIMS. Cr concentration measurements showed that the greatest Cr(VI) reduction occurred in the sulfate columns. Our preliminary Cr isotopic data show that under these conditions the delta 53Cr value increased from close to 0 to 4 per mil while the Cr concentration decreased from 260 ppb to 30 ppb in the effluent. This yields an apparent fractionation factor of 0.9979 (2.1 per mil). A decrease in Cr concentration from 260 ppb to 190 ppb in a nitrate-reducing column was accompanied by an increase of 1 per mil in delta 53Cr. Further Cr isotopic data will be presented and the effects of differing flow rates and electron acceptors will be

  3. Pacific lamprey (Entosphenus tridentatus) ammocoetes exposed to contaminated Portland Harbor sediments: Method development and effects on survival, growth, and behavior.

    PubMed

    Unrein, Julia R; Morris, Jeffrey M; Chitwood, Rob S; Lipton, Joshua; Peers, Jennifer; van de Wetering, Stan; Schreck, Carl B

    2016-08-01

    Many anthropogenic disturbances have contributed to the decline of Pacific lampreys (Entosphenus tridentatus), but potential negative effects of contaminants on lampreys are unclear. Lamprey ammocoetes are the only detritivorous fish in the lower Willamette River, Oregon, USA, and have been observed in Portland Harbor sediments. Their long benthic larval stage places them at risk from the effects of contaminated sediment. The authors developed experimental methods to assess the effects of contaminated sediment on the growth and behavior of field-collected ammocoetes reared in a laboratory. Specifically, they developed methods to assess individual growth and burrowing behavior. Burrowing performance demonstrated high variability among contaminated sediments; however, ammocoetes presented with noncontaminated reference sediment initiated burrowing more rapidly and completed it faster. Ammocoete reemergence from contaminated sediments suggests avoidance of some chemical compounds. The authors conducted long-term exposure experiments on individually held ammocoetes using sediment collected from their native Siletz River, which included the following: contaminated sediments collected from 9 sites within Portland Harbor, 2 uncontaminated reference sediments collected upstream, 1 uncontaminated sediment with characteristics similar to Portland Harbor sediments, and clean sand. They determined that a 24-h depuration period was sufficient to evaluate weight changes and observed no mortality or growth effects in fish exposed to any of the contaminated sediments. However, the effect on burrowing behavior appeared to be a sensitive endpoint, with potentially significant implications for predator avoidance. Environ Toxicol Chem 2016;35:2092-2102. © 2016 SETAC. PMID:26762215

  4. Pacific lamprey (Entosphenus tridentatus) ammocoetes exposed to contaminated Portland Harbor sediments: Method development and effects on survival, growth, and behavior.

    PubMed

    Unrein, Julia R; Morris, Jeffrey M; Chitwood, Rob S; Lipton, Joshua; Peers, Jennifer; van de Wetering, Stan; Schreck, Carl B

    2016-08-01

    Many anthropogenic disturbances have contributed to the decline of Pacific lampreys (Entosphenus tridentatus), but potential negative effects of contaminants on lampreys are unclear. Lamprey ammocoetes are the only detritivorous fish in the lower Willamette River, Oregon, USA, and have been observed in Portland Harbor sediments. Their long benthic larval stage places them at risk from the effects of contaminated sediment. The authors developed experimental methods to assess the effects of contaminated sediment on the growth and behavior of field-collected ammocoetes reared in a laboratory. Specifically, they developed methods to assess individual growth and burrowing behavior. Burrowing performance demonstrated high variability among contaminated sediments; however, ammocoetes presented with noncontaminated reference sediment initiated burrowing more rapidly and completed it faster. Ammocoete reemergence from contaminated sediments suggests avoidance of some chemical compounds. The authors conducted long-term exposure experiments on individually held ammocoetes using sediment collected from their native Siletz River, which included the following: contaminated sediments collected from 9 sites within Portland Harbor, 2 uncontaminated reference sediments collected upstream, 1 uncontaminated sediment with characteristics similar to Portland Harbor sediments, and clean sand. They determined that a 24-h depuration period was sufficient to evaluate weight changes and observed no mortality or growth effects in fish exposed to any of the contaminated sediments. However, the effect on burrowing behavior appeared to be a sensitive endpoint, with potentially significant implications for predator avoidance. Environ Toxicol Chem 2016;35:2092-2102. © 2016 SETAC.

  5. Pacific lamprey (Entosphenus tridentatus) ammocoetes exposed to contaminated Portland Harbor sediments: Method development and effects on survival, growth, and behavior

    USGS Publications Warehouse

    Unrein, Julia R.; Morris, Jeffrey M.; Chitwood, Rob S.; Lipton, Joshua; Peers, Jennifer; van de Wetering, Stan; Schreck, Carl B.

    2016-01-01

    Many anthropogenic disturbances have contributed to the decline of Pacific lampreys (Entosphenus tridentatus), but potential negative effects of contaminants on lampreys are unclear. Lamprey ammocoetes are the only detritivorous fish in the lower Willamette River, Oregon, USA, and have been observed in Portland Harbor sediments. Their long benthic larval stage places them at risk from the effects of contaminated sediment. The authors developed experimental methods to assess the effects of contaminated sediment on the growth and behavior of field-collected ammocoetes reared in a laboratory. Specifically, they developed methods to assess individual growth and burrowing behavior. Burrowing performance demonstrated high variability among contaminated sediments; however, ammocoetes presented with noncontaminated reference sediment initiated burrowing more rapidly and completed it faster. Ammocoete reemergence from contaminated sediments suggests avoidance of some chemical compounds. The authors conducted long-term exposure experiments on individually held ammocoetes using sediment collected from their native Siletz River, which included the following: contaminated sediments collected from 9 sites within Portland Harbor, 2 uncontaminated reference sediments collected upstream, 1 uncontaminated sediment with characteristics similar to Portland Harbor sediments, and clean sand. They determined that a 24-h depuration period was sufficient to evaluate weight changes and observed no mortality or growth effects in fish exposed to any of the contaminated sediments. However, the effect on burrowing behavior appeared to be a sensitive endpoint, with potentially significant implications for predator avoidance.

  6. Do aquatic insects avoid cadmium-contaminated sediments?

    SciTech Connect

    Hare, L.; Shooner, F.

    1995-06-01

    The long-term colonization of profundal lake sediments having a range of spiked cadmium (Cd) concentrations (0.007 to 2.7 {mu}mol/g dry wt.) was measured in the field. Population densities of two of the most abundant colonizing insects (the chironomids Procladius [Holotanypus] sp., and Sergentia coracina) were unrelated to the Cd gradient, even though both taxa accumulated Cd in direct relation to its concentration in sediment Cd gradient Cd gradient. Cadmium concentrations in Chironomus (salinarius gp.) sp. larvae also responded positively to the sediment Cd gradient and ranged from 0.2 to 50 {mu}g/g. In contrast with the two other taxa, the abundance of Chironomus (salinarius gp.) sp. was the result of a behavioral or a toxic response, larvae of the three chironomid taxa were given a choice between field-control and Cd-spiked sediments in the laboratory. None of the taxa avoided the Cd-spiked sediments, suggesting that the lower abundance of Chironomus (salinarius gp.) sp. at high Cd concentrations in the field was due to Cd toxicity and not to avoidance of the Cd-rich sediments.

  7. [Contaminative features of heavy metals for tidal sediment cores in Tianjin Bohai Bay].

    PubMed

    Qin, Yan-wen; Meng, Wei; Zheng, Bin-hui; Zhang, Lei; Su, Yi-bing

    2006-02-01

    Three sediment cores were collected in Nov. of 2003 from Dagu estuary to Qikou estuary. The grain size, TOC and heavy metal contents of core sediments were analyzed in order to study the geochemical characteristics, contamination features and the spatial and vertical distribution characters for heavy metals of tidal zones in Bohai Bay. The grain size of tidal sediments becomes finer from north to south. Ultrafine, fine and power sand are the main compositions in the sediment of Dagu and Duliujian estuary. The sediment of Qikou estuary is mainly composed by power and ultrafine sand. The vertical distribution trends of three sediment cores indicate that the grain-size becomes bigger from the bottom to the upper. The distribution of Fe, Al, Mn contents has distinct negative correlation with the grain-size of sediment, that is to say, the fine-grained sediments have higher contents of Fe, Al, Mn. Pb, Zn and Cd are the dominating contaminative elements in tidal sediments of Bohai Bay. Their contents are higher than the corresponding environmental background values, indicating of the anthropogenic enrichment.

  8. Characterization and Extraction of Uranium Contamination Perched within the Deep Vadose Zone at the Hanford Site, Washington State

    NASA Astrophysics Data System (ADS)

    Williams, B. A.; Rohay, V. J.; Benecke, M. W.; Chronister, G. B.; Doornbos, M. H.; Morse, J.

    2012-12-01

    A highly contaminated perched water zone has been discovered in the deep vadose zone above the unconfined aquifer during drilling of wells to characterize groundwater contamination within the 200 East Area of the U.S. Department of Energy's Hanford Site in southeast Washington. The perched water, which contains nitrate, uranium, and technetium-99 at concentrations that have exceeded 100,000 μg/L, 70,000 μg/L, and 45,000 pCi/L respectively, is providing contamination to the underlying unconfined aquifer. A perched zone extraction well has been installed and is successfully recovering the contaminated perched water as an early remedial measure to reduce impacts to the unconfined aquifer. The integration and interpretation of various borehole hydrogeologic, geochemical, and geophysical data sets obtained during drilling facilitated the delineation of the perching horizon and determination of the nature and extent of the perched contamination. Integration of the borehole geologic and geophysical logs defined the structural elevation and thickness of the perching low permeability silt interval. Borehole geophysical moisture logs, gamma logs, and sample data allowed detailed determination of the elevation and thickness of the oversaturated zone above the perching horizon, and the extent and magnitude of the radiological uranium contamination within the perching interval. Together, these data sets resolved the nature of the perching horizon and the location and extent of the contaminated perched water within the perching zone, allowing an estimation of remaining contaminant extent. The resulting conceptual model indicates that the contaminated perched water is contained within a localized sand lens deposited in a structural low on top of a semi-regional low-permeability silt layer. The top of the sand lens is approximately 72 m (235 ft) below ground surface; the maximum thickness of the sand lens is approximately 3 m (10 ft). The lateral and vertical extent of the

  9. Hydrocarbon depuration and abiotic changes in artificially oil contaminated sediment in the subtidal

    NASA Astrophysics Data System (ADS)

    Berge, John A.; Lichtenthaler, Rainer G.; Oreld, Frøydis

    1987-04-01

    North Sea crude oil was mixed with sediment in concentrations similar to those found in heavily polluted areas (10 000 and 18 000 ppm) and placed in experimental boxes in the subtidal. Experiments were performed in two Norwegian fjords, the eutrophicated Oslofjord (experimental period of 3 months) and the non-eutrophicated Raunefjord (13 months). Physical and chemical responses of the contaminated sediment were compared with similarly treated control sediment without oil. Depuration was investigated using gas and liquid chromatographic analyses for determination of total hydrocarbon content and selected single aromatic components. Biodegradation was followed using n-alkane/branched alkane ratios. No depuration or biodegradation of hydrocarbon, or pronounced changes in sediment nitrogen and carbon content were observed after exposure in the Oslofjord. In the Raunefjord the redox potential was reduced by 75-200 mV in the oil contaminated sediment after 9 and 13 months. In the control sediment nitrogen and carbon content were significantly reduced after 9 and 13 months but did not change in the oil contaminated sediment except at the sediment surface (0-1 cm). A significantly higher macrofaunal biomass was found in the control sediment after 9 and 13 months but not after 5 months. After 13 months of exposure in the Raunefjord 33% of the originally added oil remained in the sediment. The most soluble components such as naphthalene and methylnaphthalene were reduced by two orders of magnitude and less soluble components such as phenanthrene and methylphenanthrene by one order of magnitude. Reduction was most pronounced at the sediment surface. Biodegradation in the Raunefjord sediment was documented after an initial lag period of 4-9 months. It is suggested that lower bioturbation and resuspension rates are responsible for the reducing conditions and the conservation of carbon, nitrogen and particle size distribution in the oil contaminated sediment. Results found as a

  10. CHROMATOGRAPHIC ALTERATION OF A NONIONIC SURFACTANT MIXTURE DURING TRANSPORT IN DENSE NONAQUEOUS PHASE LIQUID CONTAMINATED SEDIMENT (R826650)

    EPA Science Inventory

    Chromatographic alteration of a nonionic surfactant mixture during transport through DNAPL-contaminated aquifer sediment may occur due to differential loss of oligomers to sediment and to dense nonaqueous phase liquid (DNAPL). These losses may significantly alter the solubilizing...

  11. Review of Techniques to Characterize the Distribution of Chromate Contamination in the Vadose Zone of the 100 Areas at the Hanford Site

    SciTech Connect

    Dresel, P. Evan; Truex, Michael J.; Sweeney, Mark D.

    2007-09-01

    The purpose of this report is to identify and evaluate the state-of-the-art techniques for characteriza¬tion of chromate contamination in the vadose zone of the 100 Areas at the Hanford Site. The techniques include direct techniques for analysis of chromium in the subsurface as well as indirect techniques to identify contamination through geophysical properties, soil moisture, or co-contaminants. Characteri¬zation for the distribution of chromium concentration in the vadose zone is needed to assess potential sources for chromate contamination plumes in groundwater at the 100-D, 100-K, and 100-B/C Areas.

  12. Metal contamination of active stream sediments in upper Weardale, northern Pennine Orefield, UK.

    PubMed

    Lord, R A; Morgan, P A

    2003-03-01

    In the Upper Weardale area the headwaters of the River Wear bisect the Northern Pennine Orefield, where Pb-Zn-F-Ba vein-type mineralisation has been exploited since the Roman Conquest. The area contains evidence of open pit, underground and hydraulic mining of base metal ores, associated mineral processing and smelting, exploitation of ironstones during the industrial revolution, recent extraction of fluorite and active quarrying. The aim of this study was to determine the extent of modern sediment contamination arising from these past activities. Samples of active stream sediments were collected from all major drainage channels at 1 km intervals. The sediments were analysed for Pb, Zn, Ba, Mn, Fe, Co, Ni, Cu, Cr, As, Sb, Ag and compared to data from earlier regional geochemical surveys of low order drainage samples using ArcView software. The significance of contamination levels was assessed using the Ontario aquatic sediment quality guidelines. Our results indicate widespread contamination of some major drainages by Pb, Mn, Zn and As at concentration levels anticipated to significantly affect use of the sediments by benthic organisms. Furthermore, Pb contamination shows persistence in stream sediments downstream towards agricultural areas of the floodplain and drinking water abstraction points, above which interaction with colliery mine water discharges may occur. PMID:12901084

  13. Contamination of estuarine water, biota, and sediment by halogenated organic compounds: A field study

    USGS Publications Warehouse

    Pereira, W.E.; Rostad, C.E.; Chiou, C.T.; Brinton, T.I.; Barber, L.B.; Demcheck, D.K.; Demas, C.R.

    1988-01-01

    Studies conducted in the vicinity of an industrial outfall in the Calcasieu River estuary, Louisiana, have shown that water, bottom and suspended sediment, and four different species of biota are contaminated with halogenated organic compounds (HOC) including haloarenes. A "salting-out" effect in the estuary moderately enhanced the partitioning tendency of the contaminants into biota and sediments. Contaminant concentrations in water, suspended sediments, and biota were found to be far below the values predicted on the basis of the assumption of phase equilibria with respect to concentrations in bottom sediment. Relative concentration factors of HOC between biota (catfish) and bottom sediment increased with increasing octanol/estuarine water partition coefficients (Kow*), maximizing at log Kow* of about 5, although these ratios were considerably less than equilibrium values. In contrast, contaminant concentrations in water, biota, and suspended sediments were much closer to equilibrium values. Bioconcentration factors of HOC determined on the basis of lipid content for four different biotic species correlated reasonably well with equilibrium triolein/water partition coefficients (Ktw).

  14. Longshore transport modeling of the contaminated sediment in the Fukushima area

    NASA Astrophysics Data System (ADS)

    Kitamura, A.; Machida, M.; Itakura, M.; Yamada, S.

    2015-12-01

    The cesium-contaminated sediment in the Fukushima mountain area is expected to be transported by the river flow to the downstream region, and eventually to the ocean. The contaminated sediment discharged from the river to the ocean settles down to the seabed of the coastal area around the river mouth. Some part of the settled sediment is transported to the offshore region and the contamination of the coastal area is expected to decay gradually. Estimation of the environmental half-life of the contaminated sediment is important for the assessment of the safety of the edible fish in the Fukushima coastal area. Thus we need to calculate the sediment transport in the coastal area induced by various ocean phenomena, such as tidal current, river current, wave and wind-induced current. We have estimated the effect of several kinds of ocean phenomena on the coastal sediment transport, and found that the wind-induced current and the wave-induced suspension are the most dominant phenomena, while contributions from tidal current and the river flow is negligible.

  15. Metal contamination of active stream sediments in upper Weardale, northern Pennine Orefield, UK.

    PubMed

    Lord, R A; Morgan, P A

    2003-03-01

    In the Upper Weardale area the headwaters of the River Wear bisect the Northern Pennine Orefield, where Pb-Zn-F-Ba vein-type mineralisation has been exploited since the Roman Conquest. The area contains evidence of open pit, underground and hydraulic mining of base metal ores, associated mineral processing and smelting, exploitation of ironstones during the industrial revolution, recent extraction of fluorite and active quarrying. The aim of this study was to determine the extent of modern sediment contamination arising from these past activities. Samples of active stream sediments were collected from all major drainage channels at 1 km intervals. The sediments were analysed for Pb, Zn, Ba, Mn, Fe, Co, Ni, Cu, Cr, As, Sb, Ag and compared to data from earlier regional geochemical surveys of low order drainage samples using ArcView software. The significance of contamination levels was assessed using the Ontario aquatic sediment quality guidelines. Our results indicate widespread contamination of some major drainages by Pb, Mn, Zn and As at concentration levels anticipated to significantly affect use of the sediments by benthic organisms. Furthermore, Pb contamination shows persistence in stream sediments downstream towards agricultural areas of the floodplain and drinking water abstraction points, above which interaction with colliery mine water discharges may occur.

  16. A feasibility study of modeling pedogenic carbonates in soils and sediments at the US Department of Energy's Hanford Site

    SciTech Connect

    Hunter, C.R.; Busacca, A.J. )

    1990-09-01

    This study was conducted for Pacific Northwest Laboratory by Washington State University in support of the US Department of Energy's Protective Barrier and Warning Marker System Development Program. The objective of this study was to determine the feasibility of deriving information about past water movement patterns from Holocene-age soils in the Hanford region, and using mathematical simulation modeling of pedogenic carbonate accumulations in layered sediments as a performance assessment tool for protective barrier development. The pedogenic carbonate models would serve two purposes in barrier performance assessment: to reconstruct Holocene water movement from the distribution of carbonates in layered sediments as an analog of future water movement in protective barriers, and to simulate the feedback effect of carbonate accumulation on soil hydraulic properties and unsaturated recharge in proposed protective barrier designs. The study progressed in three phases. The first phase was a review and interpretation of current literature on pedogenic indicators of water movement. The review focused on pedogenic and lithogenic processes that drive carbonate accumulation in arid land soils and simulation models linking carbonate distribution to soil hydraulic properties, soil water balance, and climate. The second phase of the feasibility study identified issues and limitations associated with applying or modifying existing computer simulation codes or developing a new code. Finally, the utility of proceeding with the project was determined based on an evaluation of issues and limitations in relation to barrier performance criteria. 101 refs., 4 figs.

  17. Enhancing the bioremediation by harvesting electricity from the heavily contaminated sediments.

    PubMed

    Yang, Yonggang; Lu, Zijiang; Lin, Xunke; Xia, Chunyu; Sun, Guoping; Lian, Yingli; Xu, Meiying

    2015-03-01

    To test the long-term applicability of scaled-up sediment microbial fuel cells (SMFCs) in simultaneous bioremediation of toxic-contaminated sediments and power-supply for electronic devices, a 100 L SMFC inoculate with heavily contaminated sediments has been assembled and operated for over 2 years without external electron donor addition. The total organic chemical (TOC) degradation efficiency was 22.1% in the electricity generating SMFCs, which is significantly higher than that in the open-circuited SMFC (3.8%). The organic matters including contaminants in the contaminated sediments were sufficient for the electricity generation of SMFCs, even up to 8.5 years by the present SMFC theoretically. By using a power management system (PMS), the SMFC electricity could be harvested into batteries and used by commercial electronic devices. The results indicated that the SMFC-PMS system could be applied as a long-term and effective tool to simultaneously stimulate the bioremediation of the contaminated sediments and supply power for commercial devices.

  18. Multiwall carbon nanotubes increase the microbial community in crude oil contaminated fresh water sediments.

    PubMed

    Abbasian, Firouz; Lockington, Robin; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi

    2016-01-01

    Since crude oil contamination is one of the biggest environmental concerns, its removal from contaminated sites is of interest for both researchers and industries. In situ bioremediation is a promising technique for decreasing or even eliminating crude oil and hydrocarbon contamination. However, since these compounds are potentially toxic for many microorganisms, high loads of contamination can inhibit the microbial community and therefore reduce the removal rate. Therefore, any strategy with the ability to increase the microbial population in such circumstances can be of promise in improving the remediation process. In this study, multiwall carbon nanotubes were employed to support microbial growth in sediments contaminated with crude oil. Following spiking of fresh water sediments with different concentrations of crude oil alone and in a mixture with carbon nanotubes for 30days, the microbial profiles in these sediments were obtained using FLX-pyrosequencing. Next, the ratios of each member of the microbial population in these sediments were compared with those values in the untreated control sediment. This study showed that combination of crude oil and carbon nanotubes can increase the diversity of the total microbial population. Furthermore, these treatments could increase the ratios of several microorganisms that are known to be effective in the degradation of hydrocarbons.

  19. Complex patterns in fish - sediment mercury concentrations in a contaminated estuary: The influence of selenium co-contamination?

    NASA Astrophysics Data System (ADS)

    Jones, H. J.; Swadling, K. M.; Butler, E. C. V.; Macleod, C. K.

    2014-01-01

    Environmental mercury (Hg) loads do not always correspond to Hg concentrations in resident fish and selenium (Se) presence has been reported to play a pivotal role in mitigating Hg bioaccumulation. Total mercury (THg), methylmercury (MeHg) and Se concentrations were measured in sediments and a benthic fish species (Platycephalus bassensis) from a contaminated estuary (Derwent Estuary, Tasmania). Elevated sediment concentrations of Se did not result in increased Se concentrations in fish, but low concentrations of Se were associated with increased MeHg bioavailability (% MeHg) from sediments to fish. Where MeHg (≈99% of total Hg) concentration in fish was high Se uptake also increased, indicating that maintaining positive Se:Hg ratios may reduce the toxicity of MeHg. MeHg was detectable in sediments throughout the estuary, and a molar excess of THg over Se suggested that there was insufficient Se to prevent methylation from the sediments. Se:Hg ratios of less than 1.0 in sediments, coupled with high %MeHg fraction and high biotic sediment accumulation factors for MeHg (BSAFMeHg), indicated that the lower region of the Derwent Estuary could be a hotspot for Hg methylation, despite having significantly lower THg concentrations. In contrast, Hg bioavailability to fish from sediments close to the source may be reduced by both inorganic Hg species complexation and lower methylation rates. There was a strong association between THg and Se in estuarine sediments, suggesting that Se plays an important role in sediment Hg cycling and should be a key consideration in any future assessments of Hg methylation, bioavailability and bioaccumulation.

  20. A manual for applying the allowable residual contamination level method for decommissioning facilities on the Hanford Site

    SciTech Connect

    Napier, B.A.; Piepel, G.F.; Kennedy, W.E. Jr.; Schreckhise, R.G.

    1988-08-01

    This report describes the modifications that have been made to enhance the original Allowable Residual Contamination Level (ARCL) method to make it more applicable to site-specific analyses. This version considers the mixture of radionuclides present at the time of site characterization, the elapsed time after decommissioning when exposure to people could occur, and includes a calculation of the upper confidence limit of the potential dose based on sampling statistics that are developed during the site characterization efforts. The upper confidence limit of potential exposure can now be used for comparison against applicable radiation dose limits (i.e., 25 mrem/yr at Hanford). The level of confidence can be selected by the user. A wide range of exposure scenarios were evaluated; the rationale used to select the most limiting scenarios is explained. The radiation dose factors used for the inhalation and ingestion pathways were also updated to correspond with the radiation dosimetry methods utilized in the International Commission of Radiological Protection Publications 26 and 30 (ICRP 1977; 1979a,b, 1980, 1981, 1982a,b). This simplifies the calculations, since ''effective whole body'' doses are now calculated, and also brings the dosimetry methods used in the ARCL method in conformance with the rationale used by DOE in developing the 25 mrem/yr limit at Hanford. 46 refs., 21 figs., 15 tabs.

  1. Use of Polyphosphate to Decrease Uranium Leaching in Hanford 300 Area Smear Zone Sediments

    SciTech Connect

    Szecsody, James E.; Zhong, Lirong; Oostrom, Martinus; Vermeul, Vincent R.; Fruchter, Jonathan S.; Williams, Mark D.

    2012-09-30

    The primary objective of this study is to summarize the laboratory investigations performed to evaluate short- and long-term effects of phosphate treatment on uranium leaching from 300 area smear zone sediments. Column studies were used to compare uranium leaching in phosphate-treated to untreated sediments over a year with multiple stop flow events to evaluate longevity of the uranium leaching rate and mass. A secondary objective was to compare polyphosphate injection, polyphosphate/xanthan injection, and polyphosphate infiltration technologies that deliver phosphate to sediment.

  2. Tracing peatland geomorphology: sediment and contaminant movements in eroding and restored systems

    NASA Astrophysics Data System (ADS)

    Shuttleworth, Emma; Evans, Martin; Hutchinson, Simon; Rothwell, James

    2015-04-01

    Peatlands are an important store of soil carbon, play a vital role in global carbon cycling, and can also act as sinks of atmospherically deposited heavy metals. However, large areas of blanket peat are significantly degraded and actively eroding as a direct result of anthropogenic pressures, which negatively impacts carbon and pollutant storage. The restoration of eroding UK peatlands is a major conservation concern, and over the last decade measures have been taken to control erosion and restore large areas of degraded peat. In severely eroded peatlands, topography is highly variable, and an appreciation of geomorphological form and process is key in understanding the controls on peatland function, and in mitigating the negative impacts of peatland erosion. The blanket peats of the Peak District, Southern Pennines, UK embody many problems and pressures faced by peatlands globally, and are amongst the most heavily eroded and contaminated in the world. The near-surface layer of the peat is contaminated by high concentrations of anthropogenically derived, atmospherically deposited heavy metals which are released into the fluvial system as a consequence of widespread erosion. Whilst not desirable, this legacy of lead pollution and its release offer a unique opportunity to trace peatland sediment movements and thus investigate the controls on sediment and contaminant mobility. A suite of established field, analytical and modelling techniques have been modified and adapted for use in peatland environments and these have been successfully employed in combination to address issues of sediment and contaminant release at a range of scales, including: (i) the development of field portable XRF to assess in situ lead concentrations in wet organic sediments; (ii) adaptation of time integrated mass flux samplers to explore spatial and temporal sediment dynamics in peatland streams; and (iii) the application of sediment source fingerprinting and numerical mixing models to

  3. Relating ground water and sediment chemistry to microbial characterization at a BTEX-contaminated site.

    PubMed

    Pfiffner, S M; Palumbo, A V; Gibson, T; Ringelberg, D B; McCarthy, J F

    1997-01-01

    The National Center for Manufacturing Science is investigating bioremediation of petroleum hydrocarbon at a site near Belleville, MI. As part of this study, we examined the microbial communities to help elucidate biodegradative processes currently active at the site. We observed high densities of aerobic hydrocarbon degraders and denitrifiers in the less-contaminated sediments. Low densities of iron and sulfate reducers were measured in the same sediments. In contrast, the highly contaminated sediments showed low densities of aerobic hydrocarbon degraders and denitrifiers, and high densities of iron and sulfate reducers. Methanogens were also found in these highly contaminated sediments. These contaminated sediments also showed a higher biomass, by the phospholipid fatty acids, and greater ratios of phospholipid fatty acids, which indicate stress within the microbial community. Aquifer chemistry analyses indicated that the highly contaminated area was more reduced and had lower sulfate than the less-contaminated area. These conditions suggest that the subsurface environment at the highly contaminated area had progressed into sulfate reduction and methanogenesis. The less-contaminated area, although less reduced, also appeared to be progressing into primarily iron- and sulfate-reducing microbial communities. The proposed treatment to stimulate bioremediation includes addition of oxygen and nitrate to the subsurface. Ground water chemistry and microbial analyses revealed significant differences that resulted from the injection of dissolved oxygen and nitrate. These differences included an increase in Eh, small decrease in pH, and large decreases in BTEX, dissolved iron, and sulfate concentrations at the injection well. Injected nitrate was rapidly utilized by the subsurface microbial communities, and significant nitrite amounts were observed in the injection well and in nearby down-gradient observation wells. Microbial and molecular analyses indicated an increase in

  4. Relating ground water and sediment chemistry to microbial characterization at a BTEX-contaminated site.

    PubMed

    Pfiffner, S M; Palumbo, A V; Gibson, T; Ringelberg, D B; McCarthy, J F

    1997-01-01

    The National Center for Manufacturing Science is investigating bioremediation of petroleum hydrocarbon at a site near Belleville, MI. As part of this study, we examined the microbial communities to help elucidate biodegradative processes currently active at the site. We observed high densities of aerobic hydrocarbon degraders and denitrifiers in the less-contaminated sediments. Low densities of iron and sulfate reducers were measured in the same sediments. In contrast, the highly contaminated sediments showed low densities of aerobic hydrocarbon degraders and denitrifiers, and high densities of iron and sulfate reducers. Methanogens were also found in these highly contaminated sediments. These contaminated sediments also showed a higher biomass, by the phospholipid fatty acids, and greater ratios of phospholipid fatty acids, which indicate stress within the microbial community. Aquifer chemistry analyses indicated that the highly contaminated area was more reduced and had lower sulfate than the less-contaminated area. These conditions suggest that the subsurface environment at the highly contaminated area had progressed into sulfate reduction and methanogenesis. The less-contaminated area, although less reduced, also appeared to be progressing into primarily iron- and sulfate-reducing microbial communities. The proposed treatment to stimulate bioremediation includes addition of oxygen and nitrate to the subsurface. Ground water chemistry and microbial analyses revealed significant differences that resulted from the injection of dissolved oxygen and nitrate. These differences included an increase in Eh, small decrease in pH, and large decreases in BTEX, dissolved iron, and sulfate concentrations at the injection well. Injected nitrate was rapidly utilized by the subsurface microbial communities, and significant nitrite amounts were observed in the injection well and in nearby down-gradient observation wells. Microbial and molecular analyses indicated an increase in

  5. Exploring the role of shelf sediments in the Arctic Ocean in determining the Arctic contamination potential of neutral organic contaminants.

    PubMed

    Armitage, James M; Choi, Sung-Deuk; Meyer, Torsten; Brown, Trevor N; Wania, Frank

    2013-01-15

    The main objective of this study was to model the contribution of shelf sediments in the Arctic Ocean to the total mass of neutral organic contaminants accumulated in the Arctic environment using a standardized emission scenario for sets of hypothetical chemicals and realistic emission estimates (1930-2100) for polychlorinated biphenyl congener 153 (PCB-153). Shelf sediments in the Arctic Ocean are shown to be important reservoirs for neutral organic chemicals across a wide range of partitioning properties, increasing the total mass in the surface compartments of the Arctic environment by up to 3.5-fold compared to simulations excluding this compartment. The relative change in total mass for hydrophobic organic chemicals with log air-water partition coefficients ≥0 was greater than for chemicals with properties similar to typical POPs. The long-term simulation of PCB-153 generated modeled concentrations in shelf sediments in reasonable agreement with available monitoring data and illustrate that the relative importance of shelf sediments in the Arctic Ocean for influencing surface ocean concentrations (and therefore exposure via the pelagic food web) is most pronounced once primary emissions are exhausted and secondary sources dominate. Additional monitoring and modeling work to better characterize the role of shelf sediments for contaminant fate is recommended.

  6. ELECTROCHEMICAL DEGRADATION OF ORGANIC CONTAMINANTS IN WATER AND SEDIMENTS

    EPA Science Inventory

    Electrochemical degradation (ECD) utilizes high redox potential at the anode and low redox potential at the cathode to oxidize and/or reduce organic and inorganic contaminants. EDC of Trichloroethylene (TCE), although theoretically possible, has not been experimentally proven. Th...

  7. DISTINGUISHING ANTHROPOGENIC AND GEOGENIC IMPACTS OF SEDIMENT CONTAMINATION

    EPA Science Inventory

    Environmental forensics is an area of scientific research that addresses contamination within the environmental media of air, water, soil and biota, and is subject to law court, arbitration, public debate, or formal argumentation. Environmental forensics involves scientific studi...

  8. Avoidance of contaminated sediments by an amphipod (Melita plumulosa), A harpacticoid copepod (Nitocra spinipes), and a snail (Phallomedusa solida).

    PubMed

    Ward, Daniel J; Simpson, Stuart L; Jolley, Dianne F

    2013-03-01

    The distribution of contaminants is seldom homogeneous in aquatic systems. In the present study, the avoidance response of Melita plumulosa, Nitocra spinipes, and Phallomedusa solida when exposed to contaminated sediments was investigated. Test vessels were designed to allow the congruent placement of two sediments and assessment of the movement of organisms between the sediments. When exposed to reference sediment, each species dispersed evenly between test chambers regardless of differences in sediment particle size. In the presence of contaminated sediment, the magnitude and rate of avoidance varied. Avoidance assays showed that test species avoided contaminated sediment as early as 6, 6, and 24 h following exposure for N. spinipes, P. solida, and M. plumulosa, respectively. The 48-h avoidance response of M. plumulosa for nine contaminated sediments of varying toxicity showed that avoidance was generally greater for sediments which elicited greater 10-d lethality to this species. The study demonstrated that each of these species has the ability to respond to chemical cues in the environment to inhabit sediment that provides the best opportunity for survival. The avoidance response for each species indicates the potential for developing rapid screening methods to assess sediment quality. Evidence suggests that avoidance was related to sediment toxicity and that static 10-d toxicity methods are likely to overestimate toxicity for species, which would avoid contamination in heterogeneous field settings.

  9. Toxicological effects of short-term resuspension of metal-contaminated freshwater and marine sediments.

    PubMed

    Fetters, Kyle J; Costello, David M; Hammerschmidt, Chad R; Burton, G Allen

    2016-03-01

    Sediments in navigation-dominated waterways frequently are contaminated with a variety of particle-associated pollutants and are subject to frequent short-term resuspension events. There is little information documenting whether resuspension of metal-contaminated sediments has adverse ecological effects on resident aquatic organisms. Using a novel laboratory approach, the authors examined the mobilization of Zn, Cu, Cd, Pb, Ni, and Cr during resuspension of 1 freshwater and 2 coastal marine sediments and whether resuspension and redeposition resulted in toxicity to model organisms. Sediment flux exposure chambers were used to resuspend metal-contaminated sediments from 1 site in Lake DePue, Illinois (USA), and 2 sites in Portsmouth Naval Shipyard, Maine (USA). Short-term (4-h) resuspension of sediment at environmentally relevant suspended particulate matter concentrations (<1 g/L) resulted in metal mobilization to water that was sediment and metal specific. Overall, the net release of metals from suspended particles was limited, likely because of scavenging by organic matter and Fe oxides that formed during sediment interaction with oxic water. Minimal toxicity to organisms (survival of Hyalella azteca and Daphnia magna; survival, growth, and tissue metal concentration of Neanthes arenaceodentata; bioluminescence of Pyrocystis lunula) was observed during 4-h exposure to resuspended sediments and during 4-d to 10-d post-exposure recovery periods in uncontaminated water. Redeposited suspended particles exhibited increased metal bioavailability and toxicity to H. azteca, highlighting the potential for adverse ecological impacts because of changes in metal speciation. It is important to consider interactions between organisms' life histories and sediment disturbance regimes when assessing risks to ecosystems.

  10. Assessment of Soil Moisture and Fixatives Performance in Controlling Wind Erosion of Contaminated Soil at the Hanford Site

    SciTech Connect

    Lagos, L.E.; Gudavalli, R.K.

    2008-07-01

    During the remediation of burial grounds at the US Department of Energy's (DOE's) Hanford Site in Washington State, the dispersion of contaminated soil particles and dust is an issue that is faced by site workers on a daily basis. This contamination issue is even more of a concern when one takes into account the semi-arid characteristics of the region where the site is located. To mitigate this problem, workers at the site use a variety of engineered methods to minimize the dispersion of contaminated soil and dust particles. Once such methods is the use of water and/or suppression agents (fixatives) that stabilizes the soil prior to soil excavation, segregation, and removal activities. A primary contributor to the dispersion of contaminated soil and dust is wind soil erosion. The erosion process occurs when the wind speed exceeds a certain threshold value (threshold shear velocity), which depends on a number of factors including wind force loading, particle size, surface soil moisture, and the geometry of the soil. Thus under these circumstances the mobility of contaminated soil and generation and dispersion of particulate matter are significantly influenced by these parameters. Wind tunnel experiments were conducted at the Florida International University's Applied Research Center (FIU-ARC) to evaluate the effectiveness of three commercially available fixatives in controlling the mobility of soil particles on soil mounds when exposed to varying wind forces. The fixatives tested included: (1) a calcium chloride solution; (2) a petroleum hydrocarbon emulsion; and 3) a synthetic organic. As an initial step, approximately 500 lbs of uncontaminated soil was obtained from the Hanford Reservation in Washington State. Soil samples were placed in an open-loop, low speed wind tunnel and exposed to wind forces ranging from 10 to 30 miles per hour (mph). Wind erosion controlling capabilities of commercially available fixatives and soil moisture were tested at a laboratory

  11. Data Summary Report for teh Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington

    SciTech Connect

    Hulstrom, L.

    2011-02-07

    This data summary report summarizes the investigation results to evaluate the nature and distribution of Hanford Site-related contaminants present in the Columbia River. As detailed in DOE/RL-2008-11, more than 2,000 environmental samples were collected from the Columbia River between 2008 and 2010. These samples consisted of island soil, sediment, surface water, groundwater upwelling (pore water, surface water, and sediment), and fish tissue.

  12. Comparing the Accumulation of PCBs by Passive Samplers and Mussels from the Water Column at a Contaminated Sediment Site

    EPA Science Inventory

    Passive samplers, including semi-permeable membrane devices (SPMDs), solid phase microextraction (SPME) and polyethylene devices (PEDs), provide innovative tools for measuring hydrophobic organic contaminants (HOCs) originating from contaminated waters and sediments. Because the...

  13. ACTIVE CAPPING TECHNOLOGY - NEW APPROACHES FOR IN SITU REMEDIATION OF CONTAMINATED SEDIMENTS

    SciTech Connect

    Knox, A.; Paller, M.; Roberts, J.

    2012-02-13

    This study evaluated pilot-scale active caps composed of apatite, organoclay, biopolymers, and sand for the remediation of metal-contaminated sediments. The active caps were constructed in Steel Creek, at the Savannah River Site near Aiken, South Carolina. Monitoring was conducted for 12 months. Effectiveness of the caps was based on an evaluation of contaminant bioavailability, resistance to erosion, and impacts on benthic organisms. Active caps lowered metal bioavailability in the sediment during the one-year test period. Biopolymers reduced sediment suspension during cap construction, increased the pool of carbon, and lowered the release of metals. This field validation showed that active caps can effectively treat contaminants by changing their speciation, and that caps can be constructed to include more than one type of amendment to achieve multiple goals.

  14. Digestive proteases of the lugworm (Arenicola marina) inhibited by Cu from contaminated sediments

    SciTech Connect

    Chen, Z.; Mayer, L.M.

    1998-03-01

    The authors examined potential toxic effects of copper released from contaminated sediments during deposit feeding of the lugworm, Arenicola marina. Titration of Cu solution into gut fluids can result in decreases in protease activity if sufficient Cu is added. The effects of Cu on gut proteases were confirmed by incubation of gut fluids with Cu-contaminated harbor sediments. Monitoring of Cu titration into gut fluids shows that enzyme inhibition and quenching of gut protein fluorescence occur only when sufficient Cu has been added to allow inorganic Cu species to become abundant. This threshold level probably represents the exhaustion of strong binding sites that act as protection against enzyme inhibition. Thus, sediments contaminated with Cu may have inhibitory effects on digestive processes in lugworms.

  15. An evaluation of the toxicity of contaminated sediments from Waukegan Harbor, Illinois, following remediation.

    PubMed

    Kemble, N E; Hardesty, D G; Ingersoll, C G; Johnson, B T; Dwyer, F J; MacDonald, D D

    2000-11-01

    Waukegan Harbor in Illinois was designated as a Great Lakes Area of Concern due to high concentrations of sediment-associated polychlorinated biphenyls (PCBs). The objective of this study was to evaluate the toxicity of 20 sediment samples collected after remediation (primarily dredging) of Waukegan Harbor for PCBs. A 42-day whole sediment toxicity test with the amphipod Hyalella azteca (28-day sediment exposure followed by a 14-day reproductive phase) and sediment toxicity tests with Microtox(R) were conducted to evaluate sediments from Waukegan Harbor. Endpoints measured were survival, growth, and reproduction (amphipods) and luminescent light emission (bacteria). Survival of amphipods was significantly reduced in 6 of the 20 sediment samples relative to the control. Growth of amphipods (either length or weight) was significantly reduced relative to the control in all samples. However, reproduction of amphipods identified only two samples as toxic relative to the control. The Microtox basic test, conducted with organic extracts of sediments identified only one site as toxic. In contrast, the Microtox solid-phase test identified about 50% of the samples as toxic. A significant negative correlation was observed between reproduction and the concentration of three polynuclear aromatic hydrocarbons (PAHs) normalized to total organic carbon. Sediment chemistry and toxicity data were evaluated using sediment quality guidelines (consensus-based probable effect concentrations, PECs). Results of these analyses indicate that sediment samples from Waukegan Harbor were toxic to H. azteca contaminated at similar contaminant concentrations as sediment samples that were toxic to H. azteca from other areas of the United States. The relationship between PECs and the observed toxicity was not as strong for the Microtox test. The results of this study indicate that the first phase of sediment remediation in Waukegan Harbor successfully lowered concentrations of PCBs at the site

  16. High bacterial biodiversity increases degradation performance of hydrocarbons during bioremediation of contaminated harbor marine sediments.

    PubMed

    Dell'Anno, Antonio; Beolchini, Francesca; Rocchetti, Laura; Luna, Gian Marco; Danovaro, Roberto

    2012-08-01

    We investigated changes of bacterial abundance and biodiversity during bioremediation experiments carried out on oxic and anoxic marine harbor sediments contaminated with hydrocarbons. Oxic sediments, supplied with inorganic nutrients, were incubated in aerobic conditions at 20 °C and 35 °C for 30 days, whereas anoxic sediments, amended with organic substrates, were incubated in anaerobic conditions at the same temperatures for 60 days. Results reported here indicate that temperature exerted the main effect on bacterial abundance, diversity and assemblage composition. At higher temperature bacterial diversity and evenness increased significantly in aerobic conditions, whilst decreased in anaerobic conditions. In both aerobic and anaerobic conditions, biodegradation efficiencies of hydrocarbons were significantly and positively related with bacterial richness and evenness. Overall results presented here suggest that bioremediation strategies, which can sustain high levels of bacterial diversity rather than the selection of specific taxa, may significantly increase the efficiency of hydrocarbon degradation in contaminated marine sediments.

  17. Ecotoxicity of uranium to Tubifex tubifex worms (Annelida, Clitellata, Tubificidae) exposed to contaminated sediment.

    PubMed

    Lagauzère, Sandra; Terrail, Raphaële; Bonzom, Jean-Marc

    2009-02-01

    In freshwater ecosystems, sediments act as an accumulation compartment for metallic pollutants as uranium. However, they are also the habitats of numerous benthic macroinvertebrates that directly influence the structure and functioning of such environments. Consequently, these organisms could be affected by uranium. This laboratory study aimed to assess the ecotoxicity of uranium on Tubifex tubifex through 12-day exposure to contaminated sediment (0-5980 microg U g(-1) dry wt). At high concentrations (>599 microg U g(-1) dry wt), malformations were observed, and survival, biomass and burrowing activity were all reduced. This relative high resistance in polluted environments can be explained mainly by the implementation of several processes as autotomy, regeneration ability, increased production of mucus, a hormetic effect on biomass and a probable strategy for avoiding the contaminated sediment. This study represents the first assessment of uranium impact on T. tubifex at realistic concentrations in sediments near mining sites. PMID:18555526

  18. Potential Ecological Effects of Contaminants in the Exposed Par Pond Sediments

    SciTech Connect

    Paller, M.H.; Wike, L.D.

    1996-08-01

    Sediment and small mammal samples were collected from the exposed sediments of Par Pond in early 1995, shortly before the reservoir was refilled after a 4-year drawdown. Sampling was confined to elevations between 58 and 61 meters (190 and 200 feet) above mean sea level, which includes the sediments likely to be exposed if the Par Pond water level is permitted to fluctuate naturally. Both soil and small mammal samples were analyzed for a number of radionuclides and metals. Some of the soil samples were also analyzed for organic contaminants. The objective of the study was to determine if contaminant levels in the Par Pond sediments were high enough to cause deleterious ecological effects.

  19. Uptake of polycyclic aromatic hydrocarbons (PAHs) in salt marsh plants Spartina alterniflora grown in contaminated sediments.

    PubMed

    Watts, Alison Weatherly; Ballestero, Thomas P; Gardner, Kevin H

    2006-03-01

    Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in Spartina alterniflora plants grown in pots of contaminated sediment, plants grown in native sediment at a marsh contaminated with up to 900 microg/g total PAHs, and from plants grown in uncontaminated control sediment. The roots and leaves of the plants were separated, cleaned, and analyzed for PAHs. PAH compounds were detected at up to 43 microg/g dry weight in the root tissue of plants grown in pots of contaminated soil. PAH compounds were detected at up to 0.2 microg/g in the leaves of plants grown in pots of contaminated soil. Concentrations less than 0.004 microg/g were detected in the leaves of plants grown at a reference site. Root concentration factor (RCF) values ranged from 0.009 to 0.97 in the potted plants, and from 0.004 to 0.31 at the contaminated marsh site. Stem concentration factor (SCF) values ranged from 0.00004 to 0.03 in the potted plants and 0.0002 to 0.04 at the contaminated marsh. No correlation was found between the RCF value and PAH compound or chemical properties such as logKOW. SCF values were higher for the lighter PAHs in the potted plants, but not in the plants collected from the contaminated marsh. PAH concentrations in the roots of the potted plants are strongly correlated with soil concentrations, but there is less correlation for the roots grown in natural sediments. Additional plants were grown directly in PAH-contaminated water and analyzed for alkylated PAH homologs. No difference was found in leaf PAH concentrations between plants grown in contaminated water and control plants.

  20. Delineation of Hydrocarbon Contamination of Soils and Sediments With Environmental Magnetic Methods: Laboratory and Field Studies

    NASA Astrophysics Data System (ADS)

    Rijal, M. L.; Appel, E.; Porsch, K.; Kappler, A.; Blaha, U.; Petrovsky, E.

    2008-12-01

    Hydrocarbon contamination of soils and sediments is a worldwide environmental problem. The present research focuses on the study of magnetic properties of hydrocarbon contaminated soils and sediments using environmental magnetic methods both on field sites as well as in laboratory batch experiments. The main objectives of this research are i) to determine a possible application of magnetic proxies for the delineation of organic contamination in soils and sediments and ii) to examine the role of bacteria in changing soil magnetic properties after hydrocarbon contamination. A former oil field and a former military site which are heavily contaminated with hydrocarbons were studied. Additionally, three different types of natural clean soils were investigated in laboratory experiments by simulating hydrocarbon contamination in sterile and microbial active setups. Magnetic properties, soil properties, iron bioavailability, iron redox state and hydrocarbon content of samples were measured. Additionally, magnetic susceptibility (MS) was monitored weekly in laboratory batch set-ups during several months. Results from the field sites showed that there is an increase of MS and a good correlation between MS and hydrocarbon content. A weekly monitored MS result from the laboratory study clearly indicated~~10% change (increase as well as decrease) of initial MS of respective soils only in microbial active set-ups with saturation after a few weeks of experimental period. This depicts that there is a change of MS caused by microbial iron mineral transformation in presence of hydrocarbon contamination in soils. The results from the field study demonstrate that magnetic proxies can be used to localize hydrocarbon contamination. However, more field sites with hydrocarbon contaminated soils and sediments need to be investigated by using environmental magnetic methods for better understanding the factors driving such changes in magnetic properties.

  1. Comparison of methods for developing contaminant-particle size distributions for suspended sediment

    SciTech Connect

    Moore, T.D.; Burgoa, B.B.; Fontaine, T.A.

    1994-10-01

    Relationships between contaminant concentration and particle size distribution are required for modeling the transport of contaminated sediment. Standard methods, including the pipette and bottom withdrawal techniques, are unsatisfactory because of the lack of homogeneous separations of each size fraction, which results in uncertainty in the contaminant-particle size relation. In addition, the size fractions produced with these techniques do not contain enough mass for accurate contaminant analyses. To avoid these problems, an alternative method using a settling column and withdrawal times based on Stokes Law has been developed. Tests have been conducted using sediment samples contaminated with Cs-137 from a waste area at Oak Ridge National Laboratory. The samples were separated into sand, coarse and fine silt, and clay-sized particles. The results for particle size distribution and associated contaminant concentrations were evaluated for the settling column, pipette, and bottom withdrawal methods. The settling column method provides homogeneous size fractions, larger aliquots of sediment for contaminant analysis, and is quicker in some cases and less complicated to perform than the other two methods.

  2. Tracking sources of unsaturated zone and groundwater nitrate contamination using nitrogen and oxygen stable isotopes at the Hanford site, Washington.

    PubMed

    Singleton, Michael J; Woods, Katharine N; Conrad, Mark E; Depaolo, Donald J; Dresel, P Evan

    2005-05-15

    The nitrogen and oxygen isotopic compositions of nitrate in pore water extracts from unsaturated zone (UZ) core samples and groundwater samples indicate at least four potential sources of nitrate in groundwaters at the U.S. DOE Hanford Site in south-central Washington. Natural sources of nitrate identified include microbially produced nitrate from the soil column (delta15N of 4 - 8 per thousand, delta18O of -9 to 2 per thousand) and nitrate in buried caliche layers (delta15N of 0-8 per thousand, delta 18O of -6to 42 per thousand). Isotopically distinctindustrial sources of nitrate include nitric acid in low-level disposal waters (delta15N approximately per thousand, delta 18O approximately 23%o) per thousandnd co-contaminant nitrate in high-level radioactive waste from plutonium processing (6'5delta1of 8-33 % o, per thousand18delta oO -9 to 7%0). per thousandThe isotopic compositions of nitrate from 97 groundwater wells with concentrations up to 1290 mg/L NO3- have been analyzed. Stable isotope analyses from this study site, which has natural and industrial nitrate sources, provide a tool to distinguish nitrate sources in an unconfined aquiferwhere concentrations alone do not. These data indicate that the most common sources of high nitrate concentrations in groundwater at Hanford are nitric acid and natural nitrate flushed out of the UZ during disposal of low-level wastewater. Nitrate associated with high-level radioactive UZ contamination does not appear to be a major source of groundwater nitrate at this time.

  3. Radioactive Contamination of the North-western Black Sea Sediments

    NASA Astrophysics Data System (ADS)

    Gulin, S. B.; Polikarpov, G. G.; Egorov, V. N.; Martin, J. M.; Korotkov, A. A.; Stokozov, N. A.

    2002-03-01

    The paper deals with the input and deposition of the man-made radionuclides 137Cs, 238 Pu, 239+240Pu and 241Am introduced to the north-western Black Sea, over the last few decades, as the result of atmospheric nuclear weapons testing and the Chernobyl nuclear accident. One approach taken was to retrieve the deposition records of these radionuclides in the sediments. The deposition chronology was compared with monitoring data of the post-Chernobyl input of 137Cs to the NW Black Sea sediments from the Danube River. The partitioning of 137 Cs between suspended matter and water was traced along the salinity gradient in the Danube mixing zone. In sediments deposited in the vicinity of the Danube delta and the Dniepr estuary, the activity of Chernobyl 137Cs had reached its maximum 5 and 10 years after the accident, respectively. The activity ratio of 137Cs to 239+240Pu and 241 Am revealed a higher mobility of 137Cs in the Danube River basin compared to plutonium and americium. The percentage of particulate 137Cs and its distribution coefficient vs salinity have allowed the estimation of sedimentary scavenging and desorption of caesium in the Danube mixing zone. Comparison of the post-Chernobyl 137Cs input from the Danube to the 137Cs inventory in the adjacent Black Sea sediments showed that more than 70% of this radionuclide was deposited in the Danube-Black Sea mixing zone.

  4. Mercury Contaminated Sediment Sites- An Evaluation of Remedial Options

    EPA Science Inventory

    Mercury (Hg) is a naturally-occurring element that is ubiquitous in the aquatic environment. Though efforts have been made in recent years to decrease Hg emissions, historically-emitted Hg can be retained in the sediments of aquatic bodies where they may be slowly converted to m...

  5. Concentration of arsenic in water, sediments and fish species from naturally contaminated rivers.

    PubMed

    Rosso, Juan José; Schenone, Nahuel F; Pérez Carrera, Alejo; Fernández Cirelli, Alicia

    2013-04-01

    Arsenic (As) may occur in surface freshwater ecosystems as a consequence of both natural contamination and anthropogenic activities. In this paper, As concentrations in muscle samples of 10 fish species, sediments and surface water from three naturally contaminated rivers in a central region of Argentina are reported. The study area is one of the largest regions in the world with high As concentrations in groundwater. However, information of As in freshwater ecosystems and associated biota is scarce. An extensive spatial variability of As concentrations in water and sediments of sampled ecosystems was observed. Geochemical indices indicated that sediments ranged from mostly unpolluted to strongly polluted. The concentration of As in sediments averaged 6.58 μg/g ranging from 0.23 to 59.53 μg/g. Arsenic in sediments barely followed (r = 0.361; p = 0.118) the level of contamination of water. All rivers showed high concentrations of As in surface waters, ranging from 55 to 195 μg/L. The average concentration of As in fish was 1.76 μg/g. The level of contamination with As differed significantly between species. Moreover, the level of bioaccumulation of As in fish species related to the concentration of As in water and sediments also differed between species. Whilst some fish species seemed to be able to regulate the uptake of this metalloid, the concentration of As in the large catfish Rhamdia quelen mostly followed the concentration of As in abiotic compartments. The erratic pattern of As concentrations in fish and sediments regardless of the invariable high levels in surface waters suggests the existence of complex biogeochemical processes behind the distribution patterns of As in these naturally contaminated ecosystems.

  6. Thallium dispersal and contamination in surface sediments from South China and its source identification.

    PubMed

    Liu, Juan; Wang, Jin; Chen, Yongheng; Shen, Chuan-Chou; Jiang, Xiuyang; Xie, Xiaofan; Chen, Diyun; Lippold, Holger; Wang, Chunlin

    2016-06-01

    Thallium (Tl) is a non-essential element in humans and it is considered to be highly toxic. In this study, the contents, sources, and dispersal of Tl were investigated in surface sediments from a riverine system (the western Pearl River Basin, China), whose catchment has been contaminated by mining and roasting of Tl-bearing pyrite ores. The isotopic composition of Pb and total contents of Tl and other relevant metals (Pb, Zn, Cd, Co, and Ni) were measured in the pyrite ores, mining and roasting wastes, and the river sediments. Widespread contamination of Tl was observed in the sediments across the river, with the highest concentration of Tl (17.3 mg/kg) measured 4 km downstream from the pyrite industrial site. Application of a modified Institute for Reference Materials and Measurement (IRMM) sequential extraction scheme in representative sediments unveiled that 60-90% of Tl and Pb were present in the residual fraction of the sediments. The sediments contained generally lower (206)Pb/(207)Pb and higher (208)Pb/(206)Pb ratios compared with the natural Pb isotope signature (1.2008 and 2.0766 for (206)Pb/(207)Pb and (208)Pb/(206)Pb, respectively). These results suggested that a significant fraction of non-indigenous Pb could be attributed to the mining and roasting activities of pyrite ores, with low (206)Pb/(207)Pb (1.1539) and high (208)Pb/(206)Pb (2.1263). Results also showed that approximately 6-88% of Tl contamination in the sediments originated from the pyrite mining and roasting activities. This study highlights that Pb isotopic compositions could be used for quantitatively fingerprinting the sources of Tl contamination in sediments. PMID:27038575

  7. Sequential Leaching of Chromium Contaminated Sediments - A Study Characterizing Natural Attenuation

    NASA Astrophysics Data System (ADS)

    Musa, D.; Ding, M.; Beroff, S.; Rearick, M.; Perkins, G.; WoldeGabriel, G. W.; Ware, D.; Harris, R.; Kluk, E.; Katzman, D.; Reimus, P. W.; Heikoop, J. M.

    2015-12-01

    Natural attenuation is an important process in slowing down the transport of hexavalent chromium, Cr(VI), an anthropogenic environmental contaminant, either by adsorption of Cr(VI) to sediments, or by reduction to nontoxic trivalent chromium, Cr(III). The capacity and mechanism of attenuation is explored in this sequential leaching study of different particle size fractions of chromium contaminated sediments and similar uncontaminated sediments from the regional aquifer near Los Alamos, New Mexico. Using this leaching protocol each sediment sample is split in two: one half is leached three times using a 0.1 M sodium bicarbonate/carbonate solution, while the second half is leached three times using a 0.01 M nitric acid, followed by two consecutively increasing magnitudes of nitric acid concentrations. Based on the amphoteric nature of chromium, alkaline leaching is used to establish the amount of Cr(VI) sorbed on the sediment, whereas acid leaching is used to establish the amount of Cr(III). The weak acid is predicted to release the attenuated anthropogenic Cr(III), without affecting Cr-bearing minerals. The sequential, stronger, acid is anticipated to leach Cr(III)-incorporated in the minerals. The efficiency and validation of the sequential leaching method is assessed by comparing the leaching behavior of bentonite and biotite samples, with and without loaded Cr(VI). A 97% chromium mass balance of leached Cr(VI)-loaded bentonite and biotite proves the viability of this method for further use on leaching contaminated sediments. By comparing contaminated and uncontaminated sediment leachate results, of chromium and other major and trace elements, the signature of anthropogenic chromium is determined. Further mineralogical characterization of the sediments provides a quantitative measure of the natural attenuation capacity for chromium. Understanding these results is pertinent in delineating the optimal procedure for the remediation of Cr(VI) in the regional aquifer

  8. Accelerating progress at contaminated sediment sites: moving from guidance to practice.

    PubMed

    Bridges, Todd S; Nadeau, Steven C; McCulloch, Megan C

    2012-04-01

    Contaminated sediments are a pervasive problem in the United States. Significant economic, ecological, and social issues are intertwined in addressing the nation's contaminated sediment problem. Managing contaminated sediments has become increasingly resource intensive, with some investigations costing tens of millions of dollars and the majority of remediation projects proceeding at a slow pace. At present, the approaches typically used to investigate, evaluate, and remediate contaminated sediment sites in the United States have largely fallen short of producing timely, risk-based, cost-effective, long-term solutions. With the purpose of identifying opportunities for accelerating progress at contaminated sediment sites, the US Army Corps of Engineers-Engineer Research and Development Center and the Sediment Management Work Group convened a workshop with experienced experts from government, industry, consulting, and academia. Workshop participants identified 5 actions that, if implemented, would accelerate the progress and increase the effectiveness of risk management at contaminated sediment sites. These actions included: 1) development of a detailed and explicit project vision and accompanying objectives, achievable short-term and long-term goals, and metrics of remedy success at the outset of a project, with refinement occurring as needed throughout the duration of the project; 2) strategic engagement of stakeholders in a more direct and meaningful process; 3) optimization of risk reduction, risk management processes, and remedy selection addressing 2 important elements: a) the deliberate use of early action remedies, where appropriate, to accelerate risk reduction; and b) the systematic and sequential development of a suite of actions applicable to the ultimate remedy, starting with monitored natural recovery and adding engineering actions as needed to satisfy the project's objectives; 4) an incentive process that encourages and rewards risk reduction; and 5

  9. Contaminant trends in reservoir sediment cores as records of influent stream quality

    USGS Publications Warehouse

    Van Metre, P.C.; Mahler, B.J.

    2004-01-01

    When reconstructing water-quality histories from lake and reservoir cores, it is sometimes assumed that the chemical signatures in the cores reflect historical water quality in the influent streams. To investigate this assumption, concentrations of metals, PAHs, and organochlorine compounds in sediment cores were compared to those associated with an influent-stream suspended sediment for three reservoirs in Fort Worth, TX, and two reservoirs in Boston, MA, U.S.A., and interpreted in light of land-use and regulation histories. In evaluating relations between suspended sediments and cores, three levels of preservation were indicated: (1) influent concentrations and historical trends are preserved in cores (metals at all sites; some organic contaminants at some sites); (2) some loss occurs during transport and initial deposition but relative historical trends are preserved in cores (some organic contaminants at some sites); and (3) neither stream concentrations nor relative historical trends are preserved (dieldrin and p,p???-DDT). The degree of preservation of influent concentration histories varied between lakes, particularly for PAHs. The results support the use of sediment cores to infer streamwater-quality histories for many contaminants but indicate that reservoir-bottom sediment samples might underestimate concentrations of organic contaminants in some streams.

  10. Does bioleaching represent a biotechnological strategy for remediation of contaminated sediments?

    PubMed

    Fonti, Viviana; Dell'Anno, Antonio; Beolchini, Francesca

    2016-09-01

    Bioleaching is a consolidated biotechnology in the mining industry and in bio-hydrometallurgy, where microorganisms mediate the solubilisation of metals and semi-metals from mineral ores and concentrates. Bioleaching also has the potential for ex-situ/on-site remediation of aquatic sediments that are contaminated with metals, which represent a key environmental issue of global concern. By eliminating or reducing (semi-)metal contamination of aquatic sediments, bioleaching may represent an environmentally friendly and low-cost strategy for management of contaminated dredged sediments. Nevertheless, the efficiency of bioleaching in this context is greatly influenced by several abiotic and biotic factors. These factors need to be carefully taken into account before selecting bioleaching as a suitable remediation strategy. Here we review the application of bioleaching for sediment bioremediation, and provide a critical view of the main factors that affect its performance. We also discuss future research needs to improve bioleaching strategies for contaminated aquatic sediments, in view of large-scale applications. PMID:27139303

  11. Contaminated sediments: Lectures on environmental aspects of particle-associated chemicals in aquatic systems

    SciTech Connect

    Forstner, U.

    1989-01-01

    Sediments are increasingly recognized as both a carrier and a possible source of contaminants in aquatic systems. Since the early part of the century, limnological research on eutrophication problems and acidification indicated that particle-interactions can affect aquatic ecosystems. In contrast to the eutrophication and acidification problems, research on toxic chemicals has included sediment aspects from its beginning. In the lecture notes, following the description of priority pollutants related to sedimentary phases, four aspects were covered, which in an overlapping succession also reflect the development of knowledge in particle-associated pollutants during the past 25 years: the identification, surveillance, monitoring and control of sources and distribution of pollutants; the evaluation of solid/solution relations of contaminants in surface waters; the study of in-situ processes and mechanisms in pollutant transfer in various compartments of the aquatic ecosystems and, the assessment of the environmental impact of particle-bound contaminants. The last chapter focuses on dredged materials, including their disposal and the treatment of strongly contaminated sediments. Cases studies include the Niagara River/Lake Ontario pollution; solid speciation of metals in river sediments; the Rhine River; Puget Sound; Rotterdam Harbor; and the mobilization of cadmium from tidal river sediments.

  12. Temporal and spatial distributions of contaminants in sediments of Santa Monica Bay, California

    USGS Publications Warehouse

    Bay, S.M.; Zeng, E.Y.; Lorenson, T.D.; Tran, K.; Alexander, Corrine

    2003-01-01

    Contaminant inputs from wastewater discharge, a major source of contamination to Santa Monica Bay (SMB), have declined drastically during the last three decades as a result of improved treatment processes and better source control. To assess the concomitant temporal changes in the SMB sediments, a study was initiated in June 1997, in which 25 box cores were collected using a stratified random sampling design. Five sediment strata corresponding to the time intervals of 1890-1920, 1932-1963, 1965-1979, 1979-1989, and 1989-1997 were identified using 210Pb dating techniques. Samples from each stratum were analyzed for metals, 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites (DDTs), polychlorinated biphenyls (PCBs), and total organic carbon (TOC). Samples from the 1965-1979, 1979-1989, and 1989-1997 strata were also analyzed for polycyclic aromatic hydrocarbons (PAHs) and linear alkylbenzenes (LABs). Sediment metal concentrations increased from 1890-1979 and were similar during the time intervals of 1965-1979, 1979-1989, and 1989-1997, although the mass emissions of trace metals from sewage inputs declined substantially during the same time period. Trace organic contamination in SMB was generally highest in sediments corresponding to deposition during the years of 1965-1979 or 1979-1989 and showed a decline in concentration in the 1989-1997 stratum. Temporal trends of contamination were greatest in sediments collected from areas near the Hyperion Treatment Plant (HTP) outfall system and on the slope of Redondo Canyon. The highest contaminant concentrations were present in sediments near the HTP 7-mile outfall in the 1965-1979 stratum. Elevated trace metal and organic concentrations were still present in the 1989-1997 stratum of most stations, suggesting that sediment contaminants have moved vertically in the sediment column since sludge discharges from the 7-mile outfall (a dominant source of contamination to the bay) ceased in 1987. The

  13. LABORATORY REPORT ON IODINE ({sup 129}I AND {sup 127}I) SPECIATION, TRANSFORMATION AND MOBILITY IN HANFORD GROUNDWATER, SUSPENDED PARTICLES AND SEDIMENTS

    SciTech Connect

    Kaplan, D.; Santschi, P.; Xu, C.; Zhang, S.; Ho, Y.; Li, H.; Schwehr, K.

    2012-09-30

    The Hanford Site in eastern Washington produced plutonium for several decades and in the process generated billions of gallons of radioactive waste. Included in this complex mixture of waste was 50 Ci of iodine-129 ({sup 129}I). Iodine-129’s high abundance, due to its high fission yield, and extreme toxicity result in iodine-129 becoming a key risk driver at many Department of Energy (DOE) sites. The mobility of radioiodine in arid environments, such as the Hanford Site, depends largely on its chemical speciation and is also greatly affected by many other environmental factors, especially natural sediment organic matter (SOM). Groundwater radioiodine speciation has not been measured in arid regions with major plumes or large disposed {sup 129}I inventories, including the Hanford Site, Idaho National Laboratory, and Nevada Test Site. In this study, stable iodine-127 and radioiodine-129 speciation, pH, and dissolved organic carbon (DOC) of groundwater samples collected from seven wells located in the 200-West Area of the Hanford site were investigated. The most striking finding was that iodate (IO{sub 3}{sup -}) was the most abundant species. Unexpectedly, iodide (I{sup -}), which was likely the form of iodine in the source materials and the expected dominant groundwater species based on thermodynamic considerations, only accounted for 1-2% of the total iodine concentration. It is likely that the relatively high pH and the low abundance of sedimentary organic matter (SOM) that is present at the site slowed down or even inhibited the reduction of iodate, as SOM abiotically reduce iodate into iodide. Moreover, a study on the kinetics of iodide and iodate uptake and aqueous speciation transformation by three representative subsurface Hanford sediments was performed over a period of about one month. This study was carried out by using iodide-125 or iodate-125 at the ambient iodine-127concentration found at the site. Iodate K{sub d} values were on average 89% greater

  14. Contaminated Coastal Sediments in the Northeastern United States: Changing Sources Over Time

    NASA Astrophysics Data System (ADS)

    Buchholtz ten Brink, M. R.; Bothner, M. H.; Mecray, E. L.

    2001-05-01

    Regional studies of coastal sediments in the northeastern United States, conducted by the U.S. Geological Survey, show that trace metal contamination from land-based activities has occurred near all major urban centers. Concentrations of metals, such as Cu, Pb, Zn, Hg, and Ag, are 2-5 times background levels in sediments of Boston Harbor, Long Island Sound (LIS), offshore of Gulf of Maine coastal cities, and in the New York Bight (NYB). Contaminant accumulations are strongly influenced by sediment lithology and sediment transport properties in local areas, in addition to proximity to pollutant sources. Inventories are greatest in muddy depo-centers of the NYB, western LIS, and Boston Harbor. Based on sediment cores, the onset of metal contamination in the northeast occurs in the mid-1800s, with inputs increasing in the mid-1900s and decreasing (20-50%) from the 1970s to present. The increases correlate with local population growth and abundance of a bacterial sewage indicator, Clostridium perfringens. Increases of N and Corg in cores also reflect population growth and changing wastewater treatment practices. Corg values reach a high of 6% in buried sediments near the NYB disposal sites. Cores from western LIS have increasing values of C, N, and P in the most recently deposited sediments, in contrast to metal concentrations that have decreased in recent years. Cessation of sludge disposal and reduction of chemical discharges have been effective at reducing inputs; however, contaminated sediment deposits remain in rivers (e.g., the Charles), floodplains (e.g., the Housatonic), and coastal sediments. In the future, high concentrations of metal contaminants stored in buried sediments of marine and fluvial systems are likely to be a lingering and significant source of pollution to coastal environments. Until more effective source-reduction occurs, land-use and industrial practices associated with population growth in the northeast will remain dominant factors for

  15. Phosphorus amendment reduces hematological effects of lead in mallards ingesting contaminated sediments

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Audet, D.J.

    2006-01-01

    Lead poisoning of waterfowl has been reported for decades in the Coeur d?Alene River Basin (CDARB) in Idaho as a result of the ingestion of lead-contaminated sediments. This study was conducted to determine whether the addition of phosphoric acid to sediments would reduce the bioavailability and toxicity of lead to mallards (Anas platyrhynchos) as related to adverse hematological effects and altered plasma chemistries. Mallards received diets containing 12% clean sediment (controls) or 12% sediment from three different CDARB sites containing 4520, 5390, or 6990 :g/g lead (dw) with or without phosphoric acid amendment. Blood lead concentrations were significantly higher in all CDARB treatment groups and ranged from geometric mean values of 5.0 ug/g for the first two sites to 6.2 ug/g for the third site. With amendments, all blood lead concentrations became 41% to 64% lower. Red blood cell ALAD activity was depressed by 90% or more with lead-contaminated sediment from all sites and did not differ with amended diets. Free erythrocyte protoporphyrin (FEP) concentrations were elevated by contaminated sediment from all sites. Amendment decreased the elevations in FEP by as much as 80%. Hematocrit values and hemoglobin concentrations were lower for all lead site sediments by as much as 30% for site 3. Plasma enzyme activities for ALT, CK, and LDH-L were elevated by as much as 2.2-fold, and plasma creatinine concentration was 1.7-fold higher for site 3 sediment. Amendments restored hematocrit, hemoglobin, and plasma enzyme activities so that they did not differ from controls. Although amendments of phosphorus substantially reduced the bioavailability of lead and alleviated many of the adverse hematological effects, lead concentrations in the blood of mallards fed the amended sediments were still above those believed to be harmful to waterfowl under the present conditions.

  16. Computational modeling of 137Cs contaminant transfer associated with sediment transport in Abukuma River.

    PubMed

    Iwasaki, T; Nabi, M; Shimizu, Y; Kimura, I

    2015-01-01

    A numerical model capable of simulating the transfer of (137)Cs in rivers associated with transport of fine sediment is presented. The accident at Fukushima Dai-ichi Nuclear Power Plant (FDNPP) released radionuclides into the atmosphere, and after fallout several radionuclides in them, such as radiocesium ((134)Cs, (137)Cs) and radioiodine ((131)I) were adsorbed on surface soil particles around FDNPP and transported by surface water. To understand the transport and deposition of the radioactive contaminant along with surface soil particles and its flux to the ocean, we modeled the transport of the (137)Cs contaminant by computing the water flow and the associated washload and suspended load transport. We have developed a two-dimensional model to simulate the plane flow structure, sediment transport and associated (137)Cs contaminant transport in rivers by combining a shallow water flow model and an advection-diffusion equation for the transport of sediment. The proposed model has been applied to the lower reach of Abukuma River, which is the main river in the highly contaminated area around FDNPP. The numerical results indicate that most (137)Cs supplied from the upstream river reach with washload would directly reach to Pacific Ocean. In contrast, washload-oriented (137)Cs supplied from the upstream river basin has a limited role in the radioactive contamination in the river. The results also suggest that the proposed framework of computational model can be a potential tool for understanding the sediment-oriented (137)Cs behavior in rivers. PMID:24909793

  17. Computational modeling of 137Cs contaminant transfer associated with sediment transport in Abukuma River.

    PubMed

    Iwasaki, T; Nabi, M; Shimizu, Y; Kimura, I

    2015-01-01

    A numerical model capable of simulating the transfer of (137)Cs in rivers associated with transport of fine sediment is presented. The accident at Fukushima Dai-ichi Nuclear Power Plant (FDNPP) released radionuclides into the atmosphere, and after fallout several radionuclides in them, such as radiocesium ((134)Cs, (137)Cs) and radioiodine ((131)I) were adsorbed on surface soil particles around FDNPP and transported by surface water. To understand the transport and deposition of the radioactive contaminant along with surface soil particles and its flux to the ocean, we modeled the transport of the (137)Cs contaminant by computing the water flow and the associated washload and suspended load transport. We have developed a two-dimensional model to simulate the plane flow structure, sediment transport and associated (137)Cs contaminant transport in rivers by combining a shallow water flow model and an advection-diffusion equation for the transport of sediment. The proposed model has been applied to the lower reach of Abukuma River, which is the main river in the highly contaminated area around FDNPP. The numerical results indicate that most (137)Cs supplied from the upstream river reach with washload would directly reach to Pacific Ocean. In contrast, washload-oriented (137)Cs supplied from the upstream river basin has a limited role in the radioactive contamination in the river. The results also suggest that the proposed framework of computational model can be a potential tool for understanding the sediment-oriented (137)Cs behavior in rivers.

  18. Trace organic contaminants and their sources in surface sediments of Santa Monica Bay, California, USA.

    PubMed

    Venkatesan, M I; Merino, O; Baek, J; Northrup, T; Sheng, Y; Shisko, J

    2010-06-01

    Spatial distribution of selected contaminants in the surface sediments of Santa Monica Bay (SMB), California was investigated. Sediments were analyzed for DDTs (DDT and metabolites), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), linear alkylbenzenes (LABs) and coprostanol. Effluent samples from the Hyperion Treatment Plant (HTP), which discharges treated municipal wastewater effluents into SMB, were also analyzed. The inter-correlation in the distribution trends of contaminants was examined. The concentrations of contaminants were interpolated in a geographic information system to visualize their spatial distribution in the Bay. Inventories of the contaminants were also estimated. The concentrations of coprostanol, LABs and PCBs are very high only in the vicinity of the sewage outfall whereas PAHs and DDTs occur widespread in the Bay. The poor correlation of DDTs with LABs, PAHs or coprostanol content confirms the historic origin of DDTs and their absence in the contemporary wastewaters. Moderate correlation of DDTs with PCBs implies historic deposits as a major origin of PCBs. There are hot spots of DDTs at water depths of 60 and 100m and the inventory of DDTs in Bay sediments is insignificant compared to that estimated in the Palos Verdes Shelf which extends from the southern edge of Redondo Canyon around Palos Verdes Peninsula. The concentration of toxic contaminants was examined according to published sediment quality guidelines. About 20 stations contain p, p'-DDE and/or total DDTs above ERM and, PCBs between ERL and ERM indicating potential for adverse biological effects. PMID:20129659

  19. Contaminated Sediment Management in Dam Removals and River Restoration Efforts: Critical Need for Research and Policy Development

    NASA Astrophysics Data System (ADS)

    Evans, J. E.

    2015-12-01

    Over 1,000 U.S. dams have been removed (1975-2015) for reasons including obsolescence, liability concerns, water quality upgrades, fisheries, or ecosystem enhancements. Contaminated sediment can significantly complicate the approval process, cost, and timeline of a dam removal, or stop it entirely. In a dam removal, reservoir sediment changes from a sink to a source of contaminants. Recently, the Sierra Club sued to stop the removal of a large dam in Ohio because of the potential impact of phosphate releases on toxic algal blooms in Lake Erie. Heavy metals, PCBs, PAHs, pesticides, and petroleum hydrocarbons can be present in reservoir sediments. In a non-dam removal scenario, reservoir management tools range from "no action" to dredging, dewatering and removal, or sediment capping. But it is not clear how these reservoir management techniques apply to dam removals. Case studies show typically >80% of the reservoir sediment is eventually eroded, precluding sediment capping as a containment option. However, the released contaminants are diluted by mixing with "clean" sediment and are transported to different physio-chemical environments which may immobilize or biodegrade the contaminants. Poorly understood options include phased drawdown/reseeding the former reservoir to contain sediments, diking contaminant "hot spots," and addressing contaminant stratigraphy (where historical use created "hot layers" in the reservoir sediment). Research and policy development needs include: (1) assessment methods based on synergistic effects of multiple contaminants being present; (2) ways to translate the pre-removal contaminant concentrations to post-removal health risks downstream; (3) evaluation of management practices for contaminant "hot spots" and "hot layers;" (4) tools to forecast the presence of contaminated sediment using easily accessible information; and (5) ways to limit liability risk for organizations participating in dam removals involving contaminated sediment.

  20. Data Catalog for Models Simulating Release of Contaminants from Hanford Site Waste Sources

    SciTech Connect

    Riley, Robert G.; Lopresti, Charles A.

    2001-09-26

    This report provides summaries of release models used in Hanford Site assessments published over the past 14 years (1987 to 2001). Mathematical formulations that commonly have been used in recent years (i.e., salt-cake, cement, soil-debris, reactor block, glass, and corrosion) are described, along with associated parameter definitions and their units. Tables in this report provide links to data sources needed to implement the models. These links enable users to quickly locate the specific release model information and data sources they need for applying the models to future to site assessments.

  1. Mercury-contaminated sediments in the North Bay: A legacy of the Gold Rush

    USGS Publications Warehouse

    Jaffe, Bruce E.

    2001-01-01

    A legacy of the Gold Rush is mercury-contaminated sediments in the Bay. Miners used mercury to extract gold from tailings during the gold rush. A large amount of this mercury (some estimates are as great as 10,000 tons) was lost during extraction to the watershed during the gold rush era. This mercury-contaminated hydraulic mining debris made its way to the Bay.

  2. Distribution and transport of sediment-bound metal contaminants in the rio grande de tarcoles, costa rica (Central America)

    USGS Publications Warehouse

    Fuller, C.C.; Davis, J.A.; Cain, D.J.; Lamothe, P.J.; Fries Fernandez, T.L.G.; Vargas, J.A.; Murillo, M.M.

    1990-01-01

    A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments (83 times Cr background or 3000->5000 ??g/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4-6 times background and remained relatively constant over 50 km to the mouth of the river. Sediment from a mangrove swamp at the river mouth had Cr levels 2-3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.A reconnaissance survey of the extent of metal contamination in the Rio Grande de Tarcoles river system of Costa Rica indicated high levels of chromium (Cr) in the fine-grain bed sediments (83 times Cr background or 3000->5000 ??g/g). In the main channel of the river downstream of the San Jose urban area, Cr contamination in sediments was 4-6 times background and remained relatively constant over 50 km to the mouth of the river. Sediments from a mangrove swamp at the river mouth had Cr levels 2-3 times above background. Similar patterns of dilution were observed for lead (Pb) and zinc (Zn) sediment contamination, although the contamination levels were lower. The high affinity of Cr towards particulate phases, probably as Cr(III), allows the use of Cr contamination levels for delineating regions of deposition of fine-grained sediments and dilution of particle associated contaminants during transport and deposition.

  3. Methods for measuring the toxicity and bioaccumulation of sediment-associated contaminants with freshwater invertebrates

    SciTech Connect

    Not Available

    1994-06-01

    The procedures are described for testing freshwater organisms in the laboratory to evaluate the toxicity or bioaccumulation of contaminants associated with whole sediments. Sediments may be collected from the field or spiked with compounds in the laboratory. Toxicity methods are outlined for two organisms, the amphipod Hyalella azteca and the midge Chironomus tentans. The toxicity tests are conducted for 10 d in 300 ml chambers containing 100 ml of sediment and 175 ml of overlying water. Overlying water is renewed daily and test organisms are fed during the toxicity tests. The endpoint in the toxicity test with H. azteca is survival and the endpoints in the toxicity test with C. tentans are survival and growth. Procedures are primarily described for testing freshwater sediments; however, estaurine sediments (up to 15%) can also be tested with H. azteca. Guidance for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus is provided in the manual.

  4. Assessing the risk of metal mixtures in contaminated sediments on Chironomus riparius based on cytosolic accumulation.

    PubMed

    Péry, Alexandre R R; Geffard, Alain; Conrad, Arnaud; Mons, Raphaël; Garric, Jeanne

    2008-11-01

    Sediments usually contain mixtures of trace metals introduced via natural geochemical processes and anthropogenic activities. Kinetics and effects of these metals are strongly dependent both on the composition of the mixture and on the physico-chemical characteristics of the sediment. Relating effects to metal concentration may consequently be advised. However, total accumulation may be a poor predictor of metal toxicity for Chironomus riparius exposed to contaminated field sediments. As an alternative, we proposed to relate effects on Chironomus growth with cytosolic metal accumulation, measured in larvae after a short exposure period. Dose-response relationships were derived for zinc, copper, and cadmium through single-metal exposure data analysed with toxicokinetics and toxicodynamics models. They permitted, on the basis of cytosolic accumulation measures, to predict successfully the effects of mixtures of cadmium, zinc, and copper on the growth of larvae exposed to spiked sediments, as well as to field sediments in which zinc and copper were assumed to be predominant. PMID:18514899

  5. Cathodic protection by zinc sacrificial anodes: impact on marine sediment metallic contamination.

    PubMed

    Rousseau, C; Baraud, F; Leleyter, L; Gil, O

    2009-08-15

    Cathodic protection by sacrificial zinc anodes is often applied to prevent immerged metallic structures from corrosion. But this technique induces the zinc anodes dissolution, which can induce marine sediments and seawater contamination. A large scale experiment, in natural seawater, was conducted during 12 months, in order to evaluate the potential environmental impact of this continuous zinc dissolution, and of some necessary cleaning operations of the anodes surfaces. The heavy metal (Cr, Cu, Pb and Zn) concentration in water and sediment samples was monitored. A sequential extraction procedure was applied on sediment samples to differentiate the zinc mobile fractions from the residual one. A significant increase of zinc concentration was observed in water as well as in the surface sediments under the specific operating conditions. Sediments then become a secondary pollution source, as the sorbed labile zinc can be remobilized to seawater. PMID:19250740

  6. A high throughout semi-quantification method for screening organic contaminants in river sediments.

    PubMed

    Bu, Qingwei; Wang, Donghong; Liu, Xin; Wang, Zijian

    2014-10-01

    A high throughout semi-quantification method for screening nearly 900 organic contaminants (OCs) in river sediments has been developed. For most OCs tested, concentrations calculated from the proposed semi-quantification method deviated from actual values by a factor of 4. The overall recovery tests indicated that most OCs can be successfully extracted from sediments with recovery rates from 84.1 to 128.6%. To demonstrate the effectiveness of our method towards OC quantification, we screened OCs from sediments collected from the Haihe River basin. Seventy unregulated OCs (including pesticides, flame retardants, PPCPs, etc.) were identified and quantified at concentrations up to 2600 ng/g from 24 sediment samples. From these results, it is confirmed that the developed method is a useful way to fulfill a comprehensive analysis of OCs in sediments and would be valuable for the identification and prioritization of priority pollutants in watershed management.

  7. Impact of rapid urbanisation and industrialisation on river sediment metal contamination.

    PubMed

    Hayzoun, H; Garnier, C; Durrieu, G; Lenoble, V; Bancon-Montigny, C; Ouammou, A; Mounier, S

    2014-05-01

    This study aimed at evidencing contaminant inputs from a rapidly growing population and the accompanying anthropogenic activities to river sediments. The Fez metropolitan area and its impacts on the Sebou's sediments (the main Moroccan river) were chosen as a case study. The Fez agglomeration is surrounded by the river Fez, receiving the wastewaters of this developing city and then flowing into the Sebou. The sediment cores from the Fez and Sebou Rivers were extracted and analysed for major elements, butyltins and toxic metals. Normalised enrichment factors and geoaccumulation index were calculated. Toxicity risk was assessed by two sets of sediment quality guideline (SQG) indices. A moderate level of contamination by butyltins was observed, with monobutyltin being the dominant species across all sites and depths. The lowest level of metal pollution was identified in the Sebou's sediments in upstream of Fez city, whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which is a clear signature of recent inputs from the untreated wastewaters of Fez city. Consequently, the sediments of Fez and Sebou at the downstream of the confluence were found to be potentially toxic, according to the SQG levels. This finding is concerned with aquatic organisms, as well as to the riverside population, which is certainly exposed to these pollutants through the daily use of water. This study suggests that although Morocco has adopted environmental regulations aiming at restricting pollutant discharges into the natural ecosystems, such regulations are neither well respected by the main polluters nor efficiently enforced by the authorities.

  8. INTERACTIONS AMONG PHOSPHATE AMENDMENTS, MICROBES AND URANIUM MOBILITY IN CONTAMINATED SEDIMENTS

    SciTech Connect

    Knox, A

    2007-08-30

    The use of sequestering agents for the transformation of radionuclides in low concentrations in contaminated soils/sediments offers considerable potential for long-term environmental cleanup. This study evaluated the influence of four phosphate amendments and two microbial amendments on U availability. The synchrotron X-ray fluorescence mapping of the untreated U-contaminated sediment showed that U was closely associated with Mn. All tested phosphate amendments reduced aqueous U concentration more than 90%, likely due to formation of insoluble phosphate precipitates. The addition of A. piechaudii and P. putida alone were found to reduce U concentrations 63% and 31% respectively. Uranium sorption in phosphate treatments was significantly reduced in the presence of microbes. However, increased microbial activity in the treated sediment led to reduction of phosphate effectiveness. The average U concentration in 1 M MgCl{sub 2} extract from U amended sediment was 437 {micro}g/kg, but in the same sediment without microbes (autoclaved sediment), the extractable U concentration was only 103 {micro}g/kg. When the autoclaved amended sediment was treated with autoclaved biological apatite, U concentration in the 1 M MgCl{sub 2} extract was {approx}0 {micro}g/kg. Together these tests suggest that microbes may enhance U leaching and reduce phosphate amendment remedial effectiveness.

  9. A combination of bioleaching and bioprecipitation for deep removal of contaminating metals from dredged sediment.

    PubMed

    Fang, Di; Zhang, Ruichang; Zhou, Lixiang; Li, Jie

    2011-08-15

    A linked microbial process comprising bioleaching with sulfate-oxidizing bacteria and bioprecipitation with sulfate-reducing bacteria operating sequentially was investigated to deeply remove contaminating metals from dredged sediment. The results showed that sediment bioleaching resulted in a sharp decrease in sediment pH from an initial pH ∼ 7.6 to pH ∼ 2.5 within 10-20 days, approximately 65% of the main heavy metals present (Zn+Cu+Cr) were solubilized, and most of the unsolubilized metals existed in residual form of sediment. The acidic leachate that resulted from sediment bioleaching was efficiently stripped of metal sulfates using a bioprecipitation reactor when challenged with influent as low as pH ∼ 3.7. More than 99% of Zn(2+), 99% of Cu(2+) and 90% of Cr(3+) were removed from the leachate, respectively, due to the formation of ZnS, Cu(2)S and CrOOH precipitates, as confirmed by SEM-EDS and XRD detection. It was also found that alkalization of bioleached sediment using Ca(OH)(2) excluded the risk of sediment re-acidification. The ability of the combined process developed in this study to deeply remove heavy metals in insoluble sulfides or hydroxides forms makes it particularly attractive for the treatment of different types of metal contaminants.

  10. Metal impacts on microbial biomass in the anoxic sediments of a contaminated lake

    SciTech Connect

    Gough, Heidi L.; Dahl, Amy L.; Nolan, Melissa A.; Gaillard, Jean-Francois; Stahl, David A.

    2008-04-26

    Little is known about the long-term impacts of metal contamination on the microbiota of anoxic lake sediments. In this study, we examined microbial biomass and metals (arsenic, cadmium, chromium, copper, iron, lead, manganese, and zinc) in the sediments of Lake DePue, a backwater lake located near a former zinc smelter. Sediment core samples were examined using two independent measures for microbial biomass (total microscopic counts and total phospholipid-phosphate concentrations), and for various fractions of each metal (pore water extracts, sequential extractions, and total extracts of all studied metals and zinc speciation by X-ray absorption fine structure (XAFS). Zinc concentrations were up to 1000 times higher than reported for sediments in the adjacent Illinois River, and ranged from 21,400 mg/kg near the source to 1,680 mg/kg near the river. However, solid metal fractions were not well correlated with pore water concentrations, and were not good predictors of biomass concentrations. Instead, biomass, which varied among sites by as much as two-times, was inversely correlated with concentrations of pore water zinc and arsenic as established by multiple linear regression. Monitoring of other parameters known to naturally influence biomass in sediments (e.g., organic carbon concentrations, nitrogen concentrations, pH, sediment texture, and macrophytes) revealed no differences that could explain observed biomass trends. This study provides strong support for control of microbial abundance by pore water metal concentrations in contaminated freshwater sediments.

  11. Study of abyssal seafloor isolation of contaminated sediments concluded

    SciTech Connect

    Valent, P.

    1998-12-31

    Recognizing the rapidly decreasing availability of disposal sites on land, in 1993 Congress directed the Department of Defense to assess the technical and scientific feasibility of isolating contaminated dredged material on the abyssal seafloor. The Naval Research Laboratory (NRL) conducted and managed the assessment, which was funded during its first year by the Strategic Environmental Research and Development Program and in the following two years by the Defense Advanced Research Projects Agency. NRL carried out the projects in collaboration with participants from academic institutions and industrial organizations. The seafloor isolation concept is an attractive management option for contaminated dredged material because, if abyssal isolation is feasible and environmentally sound, air, land, or water supplies would not be contaminated. The participants concluded that it is technically and environmentally feasible. In ports where shipping costs are high, abyssal seafloor isolation is a cost-competitive strategy. They also outlined the architecture of a system to monitor conditions at the site and to detect and measure possible leaks of contaminated material.

  12. Desorption and bioavailability of spiked pentabromo diphenyl ether and tetrachlorodibenzo(p)dioxin in contaminated sediments.

    PubMed

    Sormunen, Arto J; Leppänen, Matti T; Kukkonen, Jussi V K

    2009-05-01

    The relationship between desorption kinetics and bioavailability of sediment-associated 2,2',4,4,5' pentabromo diphenyl ether [(14)C] (BDE-99) and 2,3,7,8 tetrachlorodibenzo(p)dioxin [(3)H] (TCDD) was examined in the contaminated sediments. The desorption kinetics were measured in a sediment-water suspension using Tenax extraction, and bioaccumulation was examined by exposing Lumbriculus variegatus (Oligochaeta) to BDE-99 and TCDD spiked sediment in a 14-day kinetic study. Both chemicals had a high affinity to the finest particle size fraction (<20 microm) and the large, very slowly desorbing fraction (58-75%). The biota-sediment accumulation factors ranged between 1.9 and 4.4 for BDE-99 and between 1.4 and 2.8 for TCDD. The chemical outflux from the rapidly desorbing fraction and influx into organisms shows the connection between desorption and bioavailability. Despite this, normalization to the rapidly desorbing fraction was unable to reduce differences in bioavailability estimates between the chemicals. Thus, it is evident that chemical extraction in the mixed system (Tenax tubes) does not fully describe the bioavailable fraction that worms face in stagnant sediments in a similar way for all chemicals. However, when all desorbing domains were included in the calculation, the difference between the chemicals disappears. Desorbing fractions were also able to reduce variability in the biota-sediment accumulation factors between the tested sediments when organic carbon-based sediment chemical concentrations were modified by the desorbing fractions.

  13. Effects of Aging Quartz Sand and Hanford Site Sediment with Sodium Hydroxide on Radionuclide Sorption Coefficients and Sediment Physical and Hydrologic Properties: Final Report for Subtask 2a

    SciTech Connect

    DI Kaplan; JC Ritter; KE Parker

    1998-12-04

    Column and batch experiments were conducted in fiscal year 1998 at Pacific Northwest National Laboratory to evaluate the effect of varying concentrations of NaOH on the sorptive, physical, and hydraulic properties of two media, a quartz sand and a composite subsurface sediment from the 200-East Area of the Hanford Site. The NaOH solutions were used as a simplified effluent from a low-activity glass waste form. These experiments were conducted over a limited (O-to 10-month) contact time, with respect to the 10,000-to 100,000-year scenarios described in the Immobilized Low-Activity Waste- Performance Assessment (ILAW-PA). Wheq these two solids were put in contact with the NaOH solutions, dissolution was evident by a substantial increase in dissolved Si concentrations in the leachates. Incremental increases in NaOH con- centrations, resulted in corresponding increases in Si concentrations. A number of physical and hydraulic properties also changed as the NaOH concentrations were changed. It was observed that quartz sand was less reactive than the composite sediment. Further, moisture- retention measurements were made on the quartz sand and composite sedimen$ which showed that the NaOH-treated solids retained more water than the non-NaOH-treated solids. Because the other chemical, physical, and hydraulic measurements did not change dramatically after the high-NaOH treatments, the greater moisture retention of the high-NaOH treatments was attributed to a "salt effect" and not to the formation of small particles during the dissolution (weathering). The distribution coefficients (IQ) for Cs and Sr were measured on the NaOH-treated sediments, with decreases from -3,000 to 1,000 and 1,300 to 300 mL/g noted, respectively, at the 0.01-to 1.O-M NaOH levels. There was no apparent trend for the Sr & values with contact time. The lack of such a trend sug- gests that dissolution of sediment particles is not controlling the drop in IQ rather, it is the competition of the added Na

  14. Determining individual mineral contributions to U(VI) adsorption in a contaminated aquifer sediment: A fluorescence spectroscopy study

    NASA Astrophysics Data System (ADS)

    Wang, Zheming; Zachara, John M.; Boily, Jean-François; Xia, Yuanxian; Resch, Tom C.; Moore, Dean A.; Liu, C.

    2011-05-01

    The adsorption and speciation of U(VI) was investigated on contaminated, fine grained sediment materials from the Hanford 300 area (SPP1 GWF) in simulated groundwater using cryogenic laser-induced U(VI) fluorescence spectroscopy combined with chemometric analysis. A series of reference minerals (montmorillonite, illite, Michigan chlorite, North Carolina chlorite, California clinochlore, quartz and synthetic 6-line ferrihydrite) was used for comparison that represents the mineralogical constituents of SPP1 GWF. Surface area-normalized Kd values were measured at U(VI) concentrations of 5 × 10 -7 and 5 × 10 -6 mol L -1 that displayed the following affinity series: 6-line-ferrihydrite > North Carolina chlorite ≈ California clinochlore > quartz ≈ Michigan chlorite > illite > montmorillonite. Both time-resolved spectra and asynchronous two-dimensional (2D) correlation analysis of SPP1 GWF at different delay times indicated that two major adsorbed U(VI) species were present in the sediment that resembled U(VI) adsorbed on quartz and phyllosilicates. Simulations of the normalized fluorescence spectra confirmed that the speciation of SPP1 GWF was best represented by a linear combination of U(VI) adsorbed on quartz (90%) and phyllosilicates (10%). However, the fluorescence quantum yield for U(VI) adsorbed on phyllosilicates was lower than quartz and, consequently, its fractional contribution to speciation may be underestimated. Spectral comparison with literature data suggested that U(VI) exist primarily as inner-sphere complexes with surface silanol groups on quartz and as surface U(VI) tricarbonate complexes on phyllosilicates.

  15. Determining Individual Mineral Contributions To U(VI) Adsorption In A Contaminated Aquifer Sediment: A Fluorescence Spectroscopy Study

    SciTech Connect

    Wang, Zheming; Zachara, John M.; Boily, Jean F.; Xia, Yuanxian; Resch, Charles T.; Moore, Dean A.; Liu, Chongxuan

    2011-05-15

    The adsorption and speciation of U(VI) was investigated on contaminated, fine grained sediment materials from the Hanford 300 area (SPP1 GWF) in simulated groundwater using cryogenic laser-induced U(VI) fluorescence spectroscopy combined with chemometric analysis. A series of reference minerals (montmorillonite, illite, Michigan chlorite, North Carolina chlorite, California clinochlore, quartz and synthetic 6-line ferrihydrite) was used for comparison that represents the mineralogical constituents of SPP1 GWF. Surface area-normalized Kd values were measured at U(VI) concentrations of 5x10-7 mol L-1 and 5x10-6 mol L-1, respectively, that displayed the following affinity series: 6-line-ferrihydrite > North Carolina chlorite ≈ California clinochlore > Michigan chlorite ≈ quartz > montmorillonite ≈ illite ≈ SPP1 GWF. Both time-resolved spectra and asynchronous two-dimensional (2D) correlation analysis of SPP1 GWF at different delay times indicated that two major adsorbed U(VI) species were present in the sediment that resembled U(VI) adsorbed on quartz and phyllosilicates. Simulations of the normalized fluorescence spectra confirmed that the speciation of SPP1 GWF was best represented by a linear combination of U(VI) adsorbed on quartz (90%) and phyllosilicates (10%). However, the fluorescence quantum yield for U(VI) adsorbed on phyllosilicates was lower than quartz and, consequently, its fractional contribution to speciation may be underestimated. Spectral comparison with literature data suggested that U(VI) exists primarily as inner-sphere U(VI) complexes with surface silanol groups on quartz while U(VI) on phyllosilicates was consistent with the formation of surface U(VI) tricarbonate complexes.

  16. Long-term effects of dredging operations program. Effects of sediment organic-matter composition on bioaccumulation of sediment organic contaminants: Interim results. Final report

    SciTech Connect

    Brannon, J.M.; Price, C.B.; Reilly, F.J.; Pennington, J.C.; McFarland, V.A.

    1991-06-01

    The relationship of sediment-bound polychlorinated biphenyl (PCB) 153 and fluoranthene to bioaccumulation by worms and clams and the relationship of sediment-bound PCB 153 and fluoranthene to concentrations in the interstitial water were examined. Bioaccumulation by both worms and clams was observed in all sediments. Apparent preference factor (APF) values showed that steady state was reached between sediment-bound contaminants and organism lipid pools. The APF values of organisms were close to the theoretical value for both contaminants in all sediments. These results showed that sediment total organic carbon (TOC) in conjunction with octanol water partition coefficients of nonpolar organic contaminants is a viable approach for predicting bioaccumulation of such compounds by infaunal organisms. Actual concentrations of contaminants in interstitial water were either overestimated or underestimated by the relationship between TOC and humic + fulvic acid organic matter fractions and sediment contaminant concentrations. Prediction of interstitial water concentrations was not as successful as use of APFs. The lack of agreement between predicted and actual interstitial water results was due to factors such as the presence of interstitial water contaminants bounds to microparticulates and dissolved organic material and the kind of organic material in the sediment.

  17. Studies on bioremediation of polycyclic aromatic hydrocarbon-contaminated sediments: bioavailability, biodegradability, and toxicity issues.

    PubMed

    Tabak, Henry H; Lazorchak, James M; Lei, Li; Khodadoust, Amid P; Antia, Jimmy E; Bagchi, Rajesh; Suidan, Makram T

    2003-03-01

    The widespread contamination by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes. This research studied a chronically PAH-contaminated estuarine sediment from the East River (ER; NY, USA) characterized by high concentrations of PAHs (approximately 4-190 ppm), sulfide, and metals and a marine sediment from New York/ New Jersey Harbor (NY/NJH; USA) with only trace quantities of PAHs (0.1-0.6 ppm). The focus was to examine the relationship between bioavailability of PAHs and their biological removal in a slurry system. Freshwater and marine sediment toxicity tests were conducted to measure baseline toxicity of both sediments to amphipods, aquatic worms, fathead and sheepshead minnow larvae, and a vascular plant; to determine the cause of toxicity; and to evaluate the effectiveness of the biotreatment strategies in reducing toxicity. Results showed the ER sediment was acutely toxic to all freshwater and marine organisms tested and that the toxicity was mainly caused by sulfide, PAHs, and metals present in the sediment. In spite of the high toxicity, most of the PAH compounds showed significant degradation in the aerobic sediment/water slurry system if the initial high oxygen demand due to the high sulfide content of the sediment was overcome. The removal of PAHs by biodegradation was closely related to their desorbed amount in 90% isopropanol solution during 24 h of contact, while the desorption of model PAH compounds from freshly spiked NY/NJH sediment did not describe the bioavailability of PAHs in the East River sediment well. The research improves our understanding of bioavailability as a controlling factor in bioremediation of PAHs and the potential of aerobic biodegradation for PAH removal and ecotoxicity reduction. PMID:12627632

  18. Studies on bioremediation of polycyclic aromatic hydrocarbon-contaminated sediments: bioavailability, biodegradability, and toxicity issues.

    PubMed

    Tabak, Henry H; Lazorchak, James M; Lei, Li; Khodadoust, Amid P; Antia, Jimmy E; Bagchi, Rajesh; Suidan, Makram T

    2003-03-01

    The widespread contamination by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes. This research studied a chronically PAH-contaminated estuarine sediment from the East River (ER; NY, USA) characterized by high concentrations of PAHs (approximately 4-190 ppm), sulfide, and metals and a marine sediment from New York/ New Jersey Harbor (NY/NJH; USA) with only trace quantities of PAHs (0.1-0.6 ppm). The focus was to examine the relationship between bioavailability of PAHs and their biological removal in a slurry system. Freshwater and marine sediment toxicity tests were conducted to measure baseline toxicity of both sediments to amphipods, aquatic worms, fathead and sheepshead minnow larvae, and a vascular plant; to determine the cause of toxicity; and to evaluate the effectiveness of the biotreatment strategies in reducing toxicity. Results showed the ER sediment was acutely toxic to all freshwater and marine organisms tested and that the toxicity was mainly caused by sulfide, PAHs, and metals present in the sediment. In spite of the high toxicity, most of the PAH compounds showed significant degradation in the aerobic sediment/water slurry system if the initial high oxygen demand due to the high sulfide content of the sediment was overcome. The removal of PAHs by biodegradation was closely related to their desorbed amount in 90% isopropanol solution during 24 h of contact, while the desorption of model PAH compounds from freshly spiked NY/NJH sediment did not describe the bioavailability of PAHs in the East River sediment well. The research improves our understanding of bioavailability as a controlling factor in bioremediation of PAHs and the potential of aerobic biodegradation for PAH removal and ecotoxicity reduction.

  19. Mercury contamination chronologies from Connecticut wetlands and Long Island Sound sediments

    USGS Publications Warehouse

    Varekamp, J.C.; Kreulen, B.; Buchholtz ten Brink, M. R.; Mecray, E.L.

    2003-01-01

    Sediment cores were used to investigate the mercury deposition histories of Connecticut and Long Island Sound. Most cores show background (pre-1800s) concentrations (50-100 ppb Hg) below 30-50 cm depth, strong enrichments up to 500 ppb Hg in the core tops with lower Hg concentrations in the surface sediments (200-300 ppb Hg). A sediment core from the Housatonic River has peak levels of 1,500 ppb Hg, indicating the presence of a Hg point source in this watershed. The Hg records were translated into Hg contamination chronologies through 210Pb dating. The onset of rig contamination occurred in ???1840-1850 in eastern Connecticut, whereas in the Housatonic River the onset is dated at around 1820. The mercury accumulation profiles show periods of peak contamination at around 1900 and at 1950-1970. Peak Hg* (Hg*= Hg measured minus Hg background) accumulation rates in the salt marshes vary, dependent on the sediment character, between 8 and 44 ng Hg/cm2 per year, whereas modern Hg* accumulation rates range from 4-17 ng Hg/cm2 per year; time-averaged Hg* accumulation rates are 15 ng Hg/cm2 per year. These Hg* accumulation rates in sediments are higher than the observed Hg atmospheric deposition rates (about 1-2 ng Hg/cm2 per year), indicating that contaminant Hg from the watershed is focused into the coastal zone. The Long Island Sound cores show similar Hg profiles as the marsh cores, but time-averaged Hg* accumulation rates are higher than in the marshes (26 ng Hg/cm2 a year) because of the different sediment characteristics. In-situ atmospheric deposition of Hg in the marshes and in Long Island Sound is only a minor component of the total Hg budget. The 1900 peak of Hg contamination is most likely related to climatic factors (the wet period of the early 1900s) and the 1950-1970 peak was caused by strong anthropogenic Hg emissions at that time. Spatial trends in total Hg burdens in cores are largely related to sedimentary parameters (amount of clay) except for the high

  20. Use of life cycle assessments to evaluate the environmental footprint of contaminated sediment remediation.

    PubMed

    Sparrevik, Magnus; Saloranta, Tuomo; Cornelissen, Gerard; Eek, Espen; Fet, Annik Magerholm; Breedveld, Gijs D; Linkov, Igor

    2011-05-15

    Ecological and human risks often drive the selection of remedial alternatives for contaminated sediments. Traditional human and ecological risk assessment (HERA) includes assessing risk for benthic organisms and aquatic fauna associated with exposure to contaminated sediments before and after remediation as well as risk for human exposure but does not consider the environmental footprint associated with implementing remedial alternatives. Assessment of environmental effects over the whole life cycle (i.e., Life Cycle Assessment, LCA) could complement HERA and help in selecting the most appropriate sediment management alternative. Even though LCA has been developed and applied in multiple environmental management cases, applications to contaminated sediments and marine ecosystems are in general less frequent. This paper implements LCA methodology for the case of the polychlorinated dibenzo-p-dioxins and -furans (PCDD/F)-contaminated Grenland fjord in Norway. LCA was applied to investigate the environmental footprint of different active and passive thin-layer capping alternatives as compared to natural recovery. The results showed that capping was preferable to natural recovery when analysis is limited to effects related to the site contamination. Incorporation of impacts related to the use of resources and energy during the implementation of a thin layer cap increase the environmental footprint by over 1 order of magnitude, making capping inferior to the natural recovery alternative. Use of biomass-derived activated carbon, where carbon dioxide is sequestered during the production process, reduces the overall environmental impact to that of natural recovery. The results from this study show that LCA may be a valuable tool for assessing the environmental footprint of sediment remediation projects and for sustainable sediment management.

  1. Incorporating bioavailability into management limits for copper in sediments contaminated by antifouling paint used in aquaculture.

    PubMed

    Simpson, Stuart L; Spadaro, David A; O'Brien, Dom

    2013-11-01

    Although now well embedded within many risk-based sediment quality guideline (SQG) frameworks, contaminant bioavailability is still often overlooked in assessment and management of contaminated sediments. To optimise management limits for metal contaminated sediments, we assess the appropriateness of a range methods for modifying SQGs based on bioavailability considerations. The impairment of reproduction of the amphipod, Melita plumulosa, and harpacticoid copepod, Nitocra spinipes, was assessed for sediments contaminated with copper from antifouling paint, located below aquaculture cages. The measurement of dilute acid-extractable copper (AE-Cu) was found to provide the most useful means for monitoring the risks posed by sediment copper and setting management limits. Acid-volatile sulfide was found to be ineffective as a SQG-modifying factor as these organisms live mostly at the more oxidised sediment water interface. SQGs normalised to %-silt/organic carbon were effective, but the benefits gained were too small to justify this approach. The effectiveness of SQGs based on AE-Cu was attributed to a small portion of the total copper being present in potentially bioavailable forms (typically<10% of the total). Much of the non-bioavailable form of copper was likely present as paint flakes in the form of copper (I) oxide, the active ingredient of the antifoulant formulation. While the concentrations of paint-associated copper are very high in some sediments, as the transformation of this form of copper to AE-Cu appears slow, monitoring and management limits should assess the more bioavailable AE-Cu forms, and further efforts be made to limit the release of paint particles into the environment.

  2. Passive sampling methods for contaminated sediments: State of the science for metals

    PubMed Central

    Peijnenburg, Willie JGM; Teasdale, Peter R; Reible, Danny; Mondon, Julie; Bennett, William W; Campbell, Peter GC

    2014-01-01

    “Dissolved” concentrations of contaminants in sediment porewater (Cfree) provide a more relevant exposure metric for risk assessment than do total concentrations. Passive sampling methods (PSMs) for estimating Cfree offer the potential for cost-efficient and accurate in situ characterization of Cfree for inorganic sediment contaminants. In contrast to the PSMs validated and applied for organic contaminants, the various passive sampling devices developed for metals, metalloids, and some nonmetals (collectively termed “metals”) have been exploited to a limited extent, despite recognized advantages that include low detection limits, detection of time-averaged trends, high spatial resolution, information about dissolved metal speciation, and the ability to capture episodic events and cyclic changes that may be missed by occasional grab sampling. We summarize the PSM approaches for assessing metal toxicity to, and bioaccumulation by, sediment-dwelling biota, including the recognized advantages and limitations of each approach, the need for standardization, and further work needed to facilitate broader acceptance and application of PSM-derived information by decision makers. Integr Environ Assess Manag 2014;10:179–196. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC. Key Points Passive sampling methods (PSMs) offer the potential for cost-efficient and accurate in situ characterization of the dissolved concentrations for inorganic sediment contaminants. PSMs are useful for evaluating the geochemical behavior of metals in surficial sediments, including determination of fluxes across the sediment-water interface, and post-depositional changes in metal speciation. Few studies have tried to link PSM responses in sediments to metal uptake and toxicity responses in benthic organisms. There is a clear need for further studies. Future PSMs could be designed to mimic saturable kinetics, which

  3. Hanford wells

    SciTech Connect

    McGhan, V.L.

    1989-06-01

    The Site Characterization and Assessment Section of the Geosciences Department at Pacific Northwest Laboratory (PNL) has compiled a list of wells located on or near the Hanford Site. Information has been updated on wells existing from the days before construction of the Hanford Works to the present. This work was funded by the US Department of Energy (DOE). The list of wells will be used by DOE contractors who need condensed, tabular information on well location, construction, and completion dates. This report does not include data on lithologic logs and ground-water contamination. Moreover, the completeness of this list is limited because of new well construction and existing well modifications, which are continually under way. Despite these limitations, this list represents the most complete description possible of data pertaining to wells on or adjacent to the Hanford Site. 7 refs., 1 fig., 2 tabs.

  4. Comparison of whole-sediment, elutriate and pore-water exposures for use in assessing sediment-associated organic contaminants in bioassays

    SciTech Connect

    Harkey, G.A. Clemson Univ., Pendleton, SC ); Landrum, P.F. ); Klaine, S.J. )

    1994-08-01

    Bioassays have frequently been used as tools to simulate exposure of benthos to sediment-associated contaminants in hazard assessments. Due to the problems involved with estimating bioavailability in whole-sediment bioassays, aqueous fractions such as elutriates and pore water have been substituted for whole-sediment exposures. The objective of this research was to compare and evaluate the bioavailability of representative neutral hydrophobic contaminants in whole sediments and in aqueous extracts of whole sediment in simultaneous bioassays, using three representative indicator species, Diporeia spp., Chironomus riparius larvae, and Lumbriculus variegatus. Aqueous extracts of whole sediment did not accurately represent the exposure observed in whole sediment. Generally, the aqueous extracts underexposed organisms compared to whole sediment, even after adjusting accumulation to the fraction of organic carbon in the test media. Accumulation comparisons among whole-sediment, elutriate, and pore-water exposures depended on sampling time. At some sampling times for some contaminants, differences in accumulation between a particular aqueous extract and whole sediment were not significant; however, these similarities were not observed for all species at the particular sampling time. Bioaccumulation and contaminant clearance data suggest that a number of factors such as the indicator species, exposure media, and chemical/physical properties of individual contaminants are responsible for the accumulation differences observed among the tested media. Normalizing bioaccumulation to the amount of organic carbon in a source compartment adjusted for bioavailability differences of only some contaminants. The authors suggest that the bioavailability of contaminants such as those tested cannot be accurately predicted in bioassays that expose organisms to aqueous representations of whole sediment.

  5. Equilibrium sampling of polychlorinated biphenyls in River Elbe sediments--Linking bioaccumulation in fish to sediment contamination.

    PubMed

    Schäfer, Sabine; Antoni, Catherine; Möhlenkamp, Christel; Claus, Evelyn; Reifferscheid, Georg; Heininger, Peter; Mayer, Philipp

    2015-11-01

    Equilibrium sampling can be applied to measure freely dissolved concentrations (cfree) of hydrophobic organic chemicals (HOCs) that are considered effective concentrations for diffusive uptake and partitioning. It can also yield concentrations in lipids at thermodynamic equilibrium with the sediment (clip⇌sed) by multiplying concentrations in the equilibrium sampling polymer with lipid to polymer partition coefficients. We have applied silicone coated glass jars for equilibrium sampling of seven 'indicator' polychlorinated biphenyls (PCBs) in sediment samples from ten locations along the River Elbe to measure cfree of PCBs and their clip⇌sed. For three sites, we then related clip⇌sed to lipid-normalized PCB concentrations (cbio,lip) that were determined independently by the German Environmental Specimen Bank in common bream, a fish species living in close contact with the sediment: (1) In all cases, cbio,lip were below clip⇌sed, (2) there was proportionality between the two parameters with high R(2) values (0.92-1.00) and (3) the slopes of the linear regressions were very similar between the three stations (0.297; 0.327; 0.390). These results confirm the close link between PCB bioaccumulation and the thermodynamic potential of sediment-associated HOCs for partitioning into lipids. This novel approach gives clearer and more consistent results compared to conventional approaches that are based on total concentrations in sediment and biota-sediment accumulation factors. We propose to apply equilibrium sampling for determining bioavailability and bioaccumulation potential of HOCs, since this technique can provide a thermodynamic basis for the risk assessment and management of contaminated sediments.

  6. Phosphorus amendment reduces bioavailability of lead to mallards ingesting contaminated sediments.

    PubMed

    Heinz, Gary H; Hoffman, David J; Audet, Daniel J

    2004-05-01

    Lead poisoning of waterfowl has been reported for decades in the Coeur d'Alene River Basin in Idaho as a result of the ingestion of lead-contaminated sediments. We conducted a study to determine whether the addition of phosphoric acid to sediments would reduce the bioavailability of lead to mallards (Anas platyrhynchos). When sediments were amended with 1% phosphorus under laboratory conditions, and diets containing 12% amended sediment were fed to mallards, reductions in tissue lead were 43% in blood, 41% in liver, and 59% in kidney with sediment containing about 4,520 microg/g lead on a dry-weight basis and 41, 30, and 57% with sediment containing about 6,990 microg/g lead. When sediments were treated with phosphorus and left to age for about 5 months in the field, reductions in lead were 56% in blood, 54% in liver, and 66% in kidney at one site with about 5,390 microg/g lead and 64, 57, and 77% at a second site with about 6,990 microg/g lead. In the field, the inability to mix the phosphoric acid uniformly and deeply enough into the sediment may have resulted in more than 1% phosphorus being added to the sediment. Although both lab and field amendments of phosphorus substantially reduced the bioavailability of lead, lead concentrations in the tissues of mallards fed the amended sediments were still above those believed to be harmful to waterfowl. Based on earlier studies of sediment toxicity to waterfowl in the Coeur d'Alene River Basin, combined with the results of our amendment study, the addition of phosphoric acid as we used it might only significantly benefit waterfowl where sediments or soils contain less than 1,000-2,000 microg/g lead.

  7. Phosphorus amendment reduces bioavailability of lead to mallards ingesting contaminated sediments

    USGS Publications Warehouse

    Heinz, G.H.; Hoffman, D.J.; Audet, D.J.

    2004-01-01

    Lead poisoning of waterfowl has been reported for decades in the Coeur d' Alene River Basin in Idaho as a result of the ingestion of lead-contaminated sediments. We conducted a study to determine whether the addition of phosphoric acid to sediments would reduce the bioavailability of lead to mallards (Anas platyrhynchos). When sediments were amended with 1 % phosphorus under laboratory conditions, and diets containing 12% amended sediment were fed to mallards, reductions in tissue lead were 43% in blood, 41 % in liver, and 59% in kidney with sediment containing about 4,520 ug/g lead on a dry-weight basis and 41, 30, and 57% with sediment containing about 6,990 ug/g lead. When sediments were treated with phosphorus and left to age for about 5 months in the field, reductions in lead were 56% in blood, 54% in liver, and 66% in kidney at one site with about 5,390 ug/g lead and 64, 57, and 77% at a second site with about 6,990 ug/g lead. In the field, the inability to mix the phosphoric acid uniformly and deeply enough into the sediment may have resulted in more than 1 % phosphorus being added to the sediment. Although both lab and field amendments of phosphorus substantially reduced the bioavailability of lead, lead concentrations in the tissues of mallards fed the amended sediments were still above those believed to be harmful to waterfowl. Based on earlier studies of sediment toxicity to waterfowl in the Coeur d' Alene River Basin, combined with the results of our amendment study, the addition of phosphoric acid as we used it might only significantly benefit waterfowl where sediments or soils contain less than 1,000-2,000 ug/g lead.

  8. Using radiosilver and plutonium isotopes to trace the dispersion of contaminated sediment in Fukushima coastal catchments

    NASA Astrophysics Data System (ADS)

    Evrard, O.; Ayrault, S.; Pointurier, F.; Onda, Y.; Laceby, J. P.; Lepage, H.; Chartin, C.; Cirella, M.; Pottin, A. C.; Hubert, A.; Lefèvre, I.

    2015-12-01

    The Fukushima Dai-ichi nuclear power plant (FDNPP) accident in March 2011 resulted in a 3000-km² radioactive pollution plume consisting predominantly of radiocesium (137Cs and 134Cs). This plume is drained by several rivers to the Pacific Ocean after flowing through less contaminated, but densely inhabited coastal plains. As the redistribution of radionuclide contaminated sediment could expose the local population to higher radiation rates, novel fingerprinting methods were developed to trace the downstream dispersion of contaminated sediment. First, the heterogeneous deposition of metastable silver-110 (110mAg) across these coastal catchments was used to investigate sediment migration. In particular, the 110mAg/137Cs activity ratio was measured in soils and river sediment demonstrating the occurrence of a seasonal cycle of soil erosion during typhoons and spring snowmelt in 2011 and 2012. However, due to the rapid decay of 110mAg (half-life of 250 days), alternative methods were required to continue tracking sediment from 2013 onwards. One promising method includes the analyses of plutonium isotopes to further understand sediment migration in the Fukushima region. For example, 241Pu/239Pu atom ratios measured in sediment collected in Fukushima coastal rivers shortly after the accident were shown to be significantly higher (0.0017 - 0.0884) than corresponding values attributed to the global fallout (0.00113 ± 0.00008). Additional analyses were conducted on sediment sampled in 2013 and 2014 after the start of decontamination works. These analyses show that the 241Pu/239Pu atom ratios decreased towards the global fallout values in rivers draining decontaminated paddy fields, demonstrating the effectiveness of remediation works.

  9. A COMPENDIUM OF CHEMICAL, PHYSICAL AND BIOLOGICAL METHODS FOR ASSESSING AND MONITORING THE REMEDIATION OF CONTAMINATED SEDIMENT SITES

    EPA Science Inventory

    Considering the many organizations which have published methods for monitoring contaminated sediments and the large number of documents on this subject, it can be a formidable task for a superfund project manager to find methods appropriate for his or her contaminated sediment si...

  10. DEVELOPMENT AND APPLICATION OF EQUILIBRIUM PARTITIONING SEDIMENT GUIDELINES IN THE ASSESSMENT OF SEDIMENT PAH CONTAMINATION

    EPA Science Inventory

    The U.S. Environmental Protection Agency used insights and methods from its water quality criteria program to develop ESGs. The discovery that freely-dissolved contaminants were the toxic form led to equilibrium partitioning being chosen to model the distribution of contaminants...

  11. Geochemical and Mineralogical Investigation of Uranium in Multi–element Contaminated, Organic–rich Subsurface Sediment

    SciTech Connect

    Qafoku, Nikolla; Gartman, Brandy N.; Kukkadapu, Ravi K.; Arey, Bruce W.; Williams, Kenneth H.; Mouser, Paula J.; Heald, Steve M.; Bargar, John R.; Janot, Noemie; Yabusaki, Steven B.; Long, Philip E.

    2014-03-02

    Alluvial sediments characterized by an abundance of refractory or lignitic organic carbon compounds and reduced Fe and S bearing mineral phases have been identified through drilling activities at the U.S. Department of Energy’s (DOE) Integrated Field Research Challenge (IFRC) site at Rifle, CO. Regions of the subsurface from which such sediments are derived are referred to as Naturally Reduced Zones (NRZ). We conducted a study with NRZ sediments with the objective to: i.) Characterize solid phase contamination of U and other co-contaminants; ii.) Document the occurrence of potential U host minerals; iii.) Determine U valence state and micron scale spatial association with co-contaminants. Macroscopic (wet chemical batch extractions and a column experiment), microscopic (SEM-EDS), and spectroscopic (Mössbauer, µ-XRF and XANES) techniques were employed. Results showed that sediments’ solid phase had significant concentrations of U, S, As, Zn, V, Cr, Cu and Se, and a remarkable assortment of potential U hosts (sorbents and/or electron donors), such as Fe oxides (hematite, magnetite, Al-substituted goethite), siderite, reduced Fe(II) bearing clays, sulfides of different types, Zn sulfide framboids and multi – element sulfides. Multi-contaminants, micron size (ca. 5 to 30 µm) areas of mainly U(IV) and some U(VI), and/or other electron scavengers or donors such as Se, As, Cr, and V were discovered in the sediments, suggesting complex micron-scale system responses to transient redox conditions, and different extent and rates of competing U redox reactions than those of single contaminant systems. Collectively, the results improve our understanding and ability to predict U and NRZ’s complex behavior and will delineate future research directions to further study both the natural attenuation and persistence of contaminant plumes and their contribution to groundwater contamination.

  12. Assessing the bioaccumulation of contaminants from sediments by fish and other aquatic organisms

    USGS Publications Warehouse

    Willford, Wayne A.; Mac, Michael J.; Hesselberg, Robert J.

    1987-01-01

    Contaminated sediments that are not acutely toxic to aquatic organisms but contain bioaccumulable toxic substances present a common, yet poorly understood problem for regulatory decision makers. In order to recommend options to minimize bioaccumulation of these toxic substances, decisionmakers need estimates of 1. which substances are available for accumulation by aquatic organisms; and 2. the potential impacts of such accumulation. The most direct and meaningful approach to estimating bioavailability is measurement of contaminant uptake by aquatic organisms exposed to the sediments of concern. Reasonably reliable methodologies exist for performing such exposures in the laboratory and in situ using marine or freshwater organisms. Such methods can demonstrate short-term potential for bioaccumulation of toxics from the sediments, but not necessarily the biological significance or long-term impact of any accumulated residues in the organisms and transfer of those residues through the food chain. Since most contaminated sediments contain a mixture of toxic substances, determination of the biological significance of their accumulation is not likely in the near future. Thus, the direct measurement of significant bioaccumulation of toxic substances from the sediments remains the most immediately useful index in a decision-making process.

  13. Metals and tributyltin sediment contamination along the Southeastern Tyrrhenian Sea coast.

    PubMed

    Lofrano, Giusy; Libralato, Giovanni; Alfieri, Aniello; Carotenuto, Maurizio

    2016-02-01

    Anthropogenic pressures can adversely affect the quality of coastal sediment posing at risk human health and the ecosystem. The Southeastern Tyrrhenian Sea (STS) coast (Italy) is still largely unexplored under this point of view. This study investigated for the first time in the area the seasonal variation and potential impact of selected metals (Cd, Cr, Cu, Ni, and Pb) and tributyltin (TBT) from sediment samples collected along the STS coast (Casalvelino Marina, Casalvelino Bay, Acciaroli Marina and Acciaroli Bay) in the perspective of Water Framework Directive and Marine Strategy Framework Directive. Data were compared to the contamination background levels of Punta Licosa reference site considering elemental enrichment factors (EFs) and single substance- and mixture-based risk characterisation ratios. Further, data were discussed considering the review of Southern Tyrrhenian Sea sediment quality. Results evidenced an increase of contamination levels from March to October showing that marinas are more impacted than bays. Sediment EFs highlighted that contamination levels were always greater than the reference site like risk characterisation ratios, suggesting the presence of potential threats. The sediment quality database generated after literature review revealed a similar situation for the whole Southern Tyrrhenian Sea. PMID:26386429

  14. Microcosm study on fate of polybrominated diphenyl ethers (PBDEs) in contaminated mangrove sediment.

    PubMed

    Zhu, Haowen; Wang, Ying; Tam, Nora F Y

    2014-01-30

    Polybrominated diphenyl ethers (PBDEs) are toxic and ubiquitous environmental contaminants, but their fate in aquatic environments is not clear. A mangrove microcosm study was employed to investigate the fate of two abundant congeners, BDE-47 and BDE-209, in contaminated sediment. After seven months, more than 90% of the spiked BDE-47 in the mangrove sediment was removed with the formation of lower brominated PBDEs, including BDE-28, -17, -15, -8, -7/4, suggesting that microbial debromination was the main contributor. Debromination of BDE-209 was also observed in the sediment but its dissipation rate was significantly lower than BDE-47. All these congeners were taken up, translocated and accumulated into the tissues of two typical mangrove plants, Kandelia obovata and Avicennia marina. PBDEs, even at very high contamination levels, in the sediment (5000ngg(-1)) and the debrominated congeners did not pose any adverse effect on the dry weight, augmentation and root/shoot ratio of either mangrove species. This is the first study to reveal that anaerobic microbial debromination and uptake by mangro