Science.gov

Sample records for harbor sediment influence

  1. Sediment toxicity in Savannah Harbor

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.

    1995-01-01

    Savannah Harbor, located near the mouth of the Savannah River, Georgia and South Carolina, is impacted by industrial and municipal effluents. Potential release of contaminants stored in harbor sediments through dredging and shipping operations requires that contaminated areas be identified for proper management of the system and protection of wildlife resources. During 1991, Hyalella azteca were exposed in 10-d static-renewal toxicity tests to pore-water and solid-phase sediment samples collected from 26 sites within Savannah Harbor. Pore-water toxicity was more pronounced than that for solidphase sediment. Toxicity and reduced leaf consumption demonstrated impaired sediment quality at specific sites within Savannah Harbor and Back River. Factors responsible for the decreased sediment quality were ammonia, alkalinity, and metal concentrations (cadmium, chromium, lead, molybdenum, and nickel). Elevated concentrations of metals and toxicities in Back River sediments indicated impacts from adjacent dredge-spoil areas.

  2. Processes influencing the transport and fate of contaminated sediments in the coastal ocean: Boston Harbor and Massachusetts Bay

    USGS Publications Warehouse

    Bothner, Michael H.; Butman, Bradford

    2007-01-01

    Most of the major urban centers of the United States including Boston, New York, Washington, Chicago, New Orleans, Miami, Los Angeles, San Francisco, and Seattle—are on a coast (fig. 1.1). All of these cities discharge treated sewage effluent into adjacent waters. In 2000, 74 percent of the U.S. population lived within 200 kilometers (km) of the coast. Between 1980 and 2002, the population density in coastal communities increased approximately 4.5 times faster than in noncoastal areas of the U.S. (Perkins, 2004). More people generate larger volumes of wastes, increase the demands on wastewater treatment, expand the area of impervious land surfaces, and use more vehicles that contribute contaminants to street runoff. According to the National Coastal Condition Report II (U.S. Environmental Protection Agency, 2005a), on the basis of coastal habitat, water and sediment quality, benthic index, and fish tissue, the overall national coastal condition is only poor to fair and the overall coastal condition in the highly populated Northeast is poor. Scientific information helps managers to prioritize and regulate coastal-ocean uses that include recreation, commercial fishing, transportation, waste disposal, and critical habitat for marine organisms. These uses are often in conflict with each other and with environmental concerns. Developing a strategy for managing competing uses while maintaining sustainability of coastal resources requires scientific understanding of how the coastal ocean system behaves and how it responds to anthropogenic influences. This report provides a summary of a multidisciplinary research program designed to improve our understanding of the transport and fate of contaminants in Massachusetts coastal waters. Massachusetts Bay and Boston Harbor have been a focus of U.S. Geological Survey (USGS) research because they provide a diverse geographic setting for developing a scientific understanding of the geology, geochemistry, and oceanography of

  3. Sediment bioaccumulation testing: Manistique Harbor sediments

    EPA Science Inventory

    Manistique Harbor AOC public meeting and availability session on August 28th in Manistique, MI. This meeting/session is organized by GLNPO; they are EPA's lead on AOC restoration efforts. The goal of the meeting is to engage with the community with all the work that has been d...

  4. Sediment resuspension characteristics in Baltimore Harbor, Maryland

    USGS Publications Warehouse

    Maa, J.P.-Y.; Sanford, L.; Halka, J.P.

    1998-01-01

    Critical bed shear stress for sediment resuspension and sediment erosion rate were measured in-situ at sites from inner to outer Baltimore Harbor using the VIMS Sea Carousel. Clay mineral contents and biological conditions were almost the same at the four study sites. The experimental results indicated that the erosion rate increased from the outer harbor toward the inner harbor with a maximum difference of about 10 times at an excess bed shear stress of 0.1 Pa. The measured critical bed shear stress strongly depended on the existence of a fluff layer. It was approximately 0.05 Pa if a fluff layer existed, and increases to about 0.1 Pa in the absence of a fluff layer.

  5. 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.

  6. Recycling of harbor sediment as lightweight aggregate.

    PubMed

    Wei, Yu-Ling; Yang, Jing-Chiang; Lin, Yong-Yang; Chuang, Shih-Yu; Wang, H Paul

    2008-01-01

    Sediment sampled from Taichung Harbor was mixed with local reservoir sediment at different weight ratios to prepare lightweight aggregate at 1050, 1100, and 1150 degrees C. A pressure of 3000 or 5000 psi was used to shape the powder mixtures into pellets before the heating processes. The results indicate that the leaching levels of trace metals from the lightweight aggregate samples are considerably reduced to levels less than Taiwan Environmental Protection Administration regulatory limits. Increasing final process temperature tends to reduce the bulk density and crushing intensity of lightweight aggregate with a concomitant increase in water sorption capability. Lightweight aggregate with the lowest bulk density, 0.49 g cm(-3) for the 5000 psi sample, was obtained with the heating process to 1150 degrees C. Based on the X-ray absorption near edge structure results, FeSO(4) decomposition with a concomitant release of SO(x) (x = 2,3) is suggested to play an important role for the bloating process in present study.

  7. 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

    / cm2 in the four cores located in the middle of the harbor, and for the single nearshore core that could be used to calculate sedimentation rates. Recognition that urban runoff has been a fairly consistent and ongoing source of PAHs to the harbor's sediments for the past 50-70 years may influence future sediment management decisions for this site with respect to long-term monitoring of surface sediments to assess cap performance. The results provided information on the ability of Eagle Harbor sediments to recover under natural conditions, identified the occurrence of creosote-derived PAH weathering in off-cap surface sediments, and distinguished between these distinct PAH sources in the harbor (creosote, urban runoff, and natural background).

  8. Evaluation of upland disposal of Oakland Harbor, California, sediment. Volume 2: Inner and outer harbor sediments. Final report

    SciTech Connect

    Lee, C.R.; Brandon, D.L.; Tatem, H.E.; Simmers, J.W.; Skogerboe, J.G.

    1993-08-01

    This report describes testing and evaluation performed by the Environmental Laboratory of the U.S. Army Engineer Waterways Experiment Station on sediment from Oakland Inner and Outer Harbor, California. Test protocols from the U.S. Environmental Protection Agency (EPA)/U.S. Army Corps of Engineers' Technical Framework for the Management of Dredged Material were used in the present evaluation to determine the potential for migration of contaminants into effluent, surface runoff, leachate, plants, and animals at an undetermined upland disposal site. One composite sediment each from Oakland Inner Harbor and Oakland Outer Harbor was tested. The composite sample consisted of sediment cores taken from the mud line to 44-ft depth. Both Oakland Harbor sediments had clayey sand textures. Total organic carbon concentrations in sediment from Oakland Inner and Outer Harbors were 3,364 and 6,042 mg/kg, respectively. Based on test results, Oakland Harbor sediments will require management of suspended solids in effluent and surface runoff and a mixing zone of at least 20 to 1 to meet the strictest assumed water quality criteria or standards. Management controls should be considered at the upland site, since plants grew poorly and contained elevated cadmium, lead, and selenium and earthworms accumulated arsenic, cadmium, and nickel. Contaminant migration, Sediment testing, Contaminated sediments, Upland disposal, Dredged material.

  9. ADSORPTION OF POLYCYCLIC AROMATIC HYDROCARBONS IN AGED HARBOR SEDIMENTS

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrophobic organic contaminants which have low aqueous solubilities and are common pollutants in harbor sediments. Adsorption and desorption isotherms for PAHs are conducted to study the abiotic sorption of PAHs in uncontami...

  10. ADSORPTION OF POLYCYCLIC AROMATIC HYDROCARBONS IN AGED HARBOR SEDIMENTS

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrophobic organic contaminants which have low aqueous solubilities and are common pollutants in harbor sediments. Adsorption and desorption isotherms for PAHs are conducted to study the abiotic sorption of PAHs in uncontami...

  11. Characterization and Fate of PAH-contaminated Sediments at the Wyckoff/Eagle Harbor Superfund Site

    SciTech Connect

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

    2002-01-01

    This study took place in Eagle Harbor, a shallow marine embayment of Bainbridge Island, WA, and the former site of the Wyckoff wood-treatment facility, which used large quantities of creosote in its wood-treating processes from the early 1900s to 1988. Analyses of 10 sediment cores using TPH fingerprinting, the distribution of 50 PAH analytes, and sediment age dating revealed the contributions of three distinct sources of PAHs to sediment contamination during various periods over the past 100 years; namely, creosote, urban runoff, and natural background. Recognition that urban runoff has been a fairly consistent and ongoing source of PAHs to the harbor's sediment for the past 50-70 years may influence future sediment management decisions for this site with respect to long-term monitoring of surface sediment to assess cap performance. The results provide information on the ability of Eagle Harbor sediment to recover under natural conditions, identified the occurrence of creosote-derived PAH weathering in off-cap surface sediment, and distinguished between these distinct PAH sources in the harbor.

  12. Hydrocarbon pollutants shape bacterial community assembly of harbor sediments.

    PubMed

    Barbato, Marta; Mapelli, Francesca; Magagnini, Mirko; Chouaia, Bessem; Armeni, Monica; Marasco, Ramona; Crotti, Elena; Daffonchio, Daniele; Borin, Sara

    2016-03-15

    Petroleum pollution results in co-contamination by different classes of molecules, entailing the occurrence of marine sediments difficult to remediate, as in the case of the Ancona harbor (Mediterranean Sea, Italy). Autochthonous bioaugmentation (ABA), by exploiting the indigenous microbes of the environment to be treated, could represent a successful bioremediation strategy. In this perspective we aimed to i) identify the main drivers of the bacterial communities' richness in the sediments, ii) establish enrichment cultures with different hydrocarbon pollutants evaluating their effects on the bacterial communities' composition, and iii) obtain a collection of hydrocarbon degrading bacteria potentially exploitable in ABA. The correlation between the selection of different specialized bacterial populations and the type of pollutants was demonstrated by culture-independent analyses, and by establishing a collection of bacteria with different hydrocarbon degradation traits. Our observations indicate that pollution dictates the diversity of sediment bacterial communities and shapes the ABA potential in harbor sediments.

  13. Hydrodynamic forcing and sediment character in Boston Harbor

    USGS Publications Warehouse

    Ravens, T.M.; Madsen, O.S.; Signell, R.P.; Adams, E.E.; Gschwend, P.M.

    1998-01-01

    Calculated annual excess skin friction stress at various locations in Quincy Bay (outer Boston Harbor) was found to be correlated positively with sediment sand content. The correlation was optimized when a critical shear stress (??c) of 0.085 Pa was assumed for the bay. The excess shear stress was correlated negatively with sediment lead (Pb) and polychlorinated biphenyl (PCB) concentrations. These correlations suggest that area surveys of properties like sand content may be sufficient to estimate ??C.

  14. Anthropogenic platinum and palladium in the sediments of Boston Harbor

    USGS Publications Warehouse

    Tuit, C.B.; Ravizza, G.E.; Bothner, Michael H.

    2000-01-01

    Anthropogenic activity has increased recent sediment concentrations of Pt and Pd in Boston Harbor by approximately 5 times background concentrations. Surface sediments and downcore profiles were investigated to evaluate Pt and Pd accumulation and behavior in urban coastal sediments. There is no clear correlation between temporal changes in Pt and Pd consumption and sediment concentration. However, Pt/Pb and Pd/Pb ratios suggest that Pt and Pd flux into the Harbor may not be decreasing with cessation of sludge input as rapidly as other metals. This is supported by the large discrepancy between fluxes associated with sludge and effluent release and those calculated from surface sediment concentrations. This evidence supports catalytic converters as a major source of Pd and Pt to Boston Harbor but cannot preclude other sources. Pd does not exhibit signs of post-burial remobilization below the mixed layer in the sediment cores, although near-surface variability in Pd concentrations may indicate a labile Pd component. Pt displays an inverse correlation with Mn above the oxic/suboxic transition, similar to behavior seen in pristine sediments where Pt is thought to be chemically mobile. This study does not support the use of Pd and Pt as tracers of recent contaminated sedimentation. However, the possibility of a labile Pt and Pd in these sediments highlights the need for further study of the biological uptake of these metals.Anthropogenic activity has increased recent sediment concentrations of Pt and Pd in Boston Harbor by approximately 5 times background concentrations. Surface sediments and downcore profiles were investigated to evaluate Pt and Pd accumulation and behavior in urban coastal sediments. There is no clear correlation between temporal changes in Pt and Pd consumption and sediment concentration. However, Pt/Pb and Pd/Pb ratios suggest that Pt and Pd flux into the Harbor may not be decreasing with cessation of sludge input as rapidly as other metals. This is

  15. PAH Mineralization and Bacterial Organotolerance in Surface Sediments of the Charleston Harbor Estuary

    DTIC Science & Technology

    2010-01-01

    organotolerance and polycyclic aromatic hydrocarbon (PAH) mineralization in Charleston Harbor and compared surface sediment from stations near a known... polycyclic aromatic hydrocarbons (PAHs) in Chesapeake Bay. Environ Sci Technol 35:2178–2183 Beney L, Gervais P (2001) MINIREVIEW: influence of the fluidity...1995) Degradation of polycyclic aromatic hydrocarbons by pure strains and Table 4 Average percent (AVG %) inhibition of bacterial production (0

  16. Using marine bioassays to classify the toxicity of Dutch harbor sediments.

    PubMed

    Stronkhorst, Joost; Schipper, Cor; Brils, Jos; Dubbeldam, Marco; Postma, Jaap; van de Hoeven, Nelly

    2003-07-01

    A procedure was developed to assess contaminated marine sediments from Dutch harbors for possible adverse biological effects using three laboratory bioassays: A 10-d survival test with the amphipod Corophium volutator, a 14-d survival test with the heart urchin Echinocardium cordatum (adults), and the bioluminescence inhibition test with the bacterium Vibrio fischeri (Microtox solid phase test LSP]). Microtox results were mathematically corrected for the modifying influence of fine sediment particles. After a validation procedure on test performance and modifying factors, respectively, 81%, 99%, and 90% of the amphipod, heart urchin, and Microtox results were approved. Lower and upper threshold limits for biological effects were set at respectively 24 and 30% mortality for C. volutator, 27 and 35% mortality for E. cordatum, and 24 and 48 toxic units for the Microtox SP based on significant differences with control sediment and the performance of reference sediments. The bioassays clearly distinguished harbor sediments that give rise to acute effects and those that do not. Threshold limits for the amphipods, heart urchins, and bacteria were exceeded in, respectively, 9 to 17%, 33 to 40%, and 23 to 50% of the sediment samples. Highest effects were observed in sediments from the northerly harbors; there was significantly less response in sediments from the Delta Region and the port of Rotterdam (The Netherlands). The procedure outlined in this paper can be used for routine screening of contaminated dredged material that is proposed for open water disposal.

  17. Distribution, sources and toxicity potential of hydrocarbons in harbor sediments: A regional assessment in SE Brazil.

    PubMed

    Pinheiro, Pedro P O; Massone, Carlos G; Carreira, Renato S

    2017-07-15

    Aliphatic and polycyclic aromatic hydrocarbons (PAHs) were quantified in harbors sediments from SE Brazil. The aims were to (i) compare harbors with distinct sizes and under the influence of different environmental pressures with respect to the sources and level of hydrocarbon contamination and (ii) evaluate the potential of adverse biological effects of sediment contamination by PAHs, based on sediment quality guidelines and toxicity equivalence quotient. The concentrations of total aliphatics (39.9μgg(-1); 22.9-113μgg(-1)) and total PAHs (727ngg(-1); 366-1760ngg(-1)) varied according to the size of and urban development around each harbor. Mixed contamination by petrogenic and pyrolytic hydrocarbons, and input of biogenic compounds, indicated the influence of both harbor activities and a myriad of urban, industrial and atmospheric inputs. The quality of sediment poses a risk to benthic biological communities, and, if dredged, this material may cause environmental damage in the waste disposal area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Environmental security of the port and harbors' sediments

    NASA Astrophysics Data System (ADS)

    Obhodas, Jasmina; Valkovic, Vladivoj; Davorin, Sudac; Matika, Dario; Pavić, Ivica

    2009-05-01

    While polluted sediments present a threat to the health of the marine ecosystem and indirectly to the public health, ammunition dump sites being mostly unprotected and neglected, present a serious threat to human security, environmental security and could be possible objects of misuse. Of special interest are sediments in ports and marinas. Those are the places where any suspicious object needs to be analyzed for the presence of explosives and CW. After analyzing several hundreds of sediment samples collected along the Adriatic coast, it has been found that they could be grouped in 7 categories: bays, beaches, villages, ports, marinas - pier area, marina - service areas and others. We have shown that the sediments in ports and harbors contain increased values of elements present in antifouling paints (Cu, As, Zn and Pb). Their presence modifies the response of survey probes while screening the sea floor for the presence of explosives and CW.

  19. Use of bathymetry for sediment characterization at Indiana Harbor

    SciTech Connect

    Petrovski, D.M.

    1995-12-31

    In 1992, US EPA, Region 5, sampled sediments within the Federal Navigation Project at Indiana Harbor, IN. Lack of a disposal site has precluded dredging since 1972, resulting in the accumulation of over 750,000 m{sup 3} of highly contaminated sediment. The Federal Project covers approximately 1.08 km{sup 2} of both enhanced4ed and secondary sediment accumulation. The purpose of the sampling effort was to characterize these sediments under Subtitle C of the Resource Conservation and Recovery Act (RCRA). Several approaches common to regulatory characterization were considered and rejected in favor of a bathymetry based procedure. Bathymetric surveys were used to identify 14 areas of thick sediment accumulation. Such areas are indicative of reduced water velocities which favor the accumulation of finer-grained sediment having a strong tendency to be associated with higher contaminant concentrations. Samples obtained from these locations should contain contaminant concentrations that exceed the mean concentrations for the project sediments. Consequently, a regulatory decision based upon these samples should be conservative. Bathymetry may provide a mechanism to reduce the number of samples necessary to characterize large sediment volumes, while maintaining an acceptable level of confidence in any derived regulatory decision.

  20. Sediment quality assessment studies in Boston Harbor, Massachusetts

    SciTech Connect

    Carr, R.S.; Chapman, D.C.; Biedenbach, J.M.; Long, E.R.; Thursby, G.; MacDonald, D.D.

    1995-12-31

    As part of NOAA`s National Status and Trends program, a bioeffects assessment study was conducted in the vicinity of Boston Harbor, Massachusetts. Surficial sediment samples were collected at 55 sites and subsamples were tested for toxicity using (1) the 10-day whole sediment test with Ampelisca abdita, (2) the sea urchin (Arbacia punctulata) fertilization and embryological development assays with sediment pore water, and (3) Microtox{trademark} assay with organic sediment extracts. Eleven percent of the samples were significantly toxic in the amphipod test, only 4% were toxic in the sea urchin fertilization test whereas all of the samples were highly toxic in the sea urchin embryological development assay; the Microtox assay determined 56% of the organic sediment extracts to be significantly toxic. Sediment chemical analyses for metals, AVS/SEM, PAHs, PCBs, and pesticides were performed on 30 of the 55 samples. Twenty-seven of the 30 samples exceeded at least one probable effects level (PEL) value. For the 20 samples that exceeded 5 or more PELS, the concordance between the predicted and observed toxicity was 20% for the amphipod test, 60% for the Microtox test, and 100% for the sea urchin embryological development assay. There were no significant correlations among the different toxicity tests or between the tests and the contaminant concentrations in the bulk sediment. Possible explanations for the apparent lack of correlation between the sediment chemistry and the toxicity tests will be discussed.

  1. Composition and source of butyltins in sediments of Kaohsiung Harbor, Taiwan

    NASA Astrophysics Data System (ADS)

    Dong, Cheng-Di; Chen, Chih-Feng; Chen, Chiu-Wen

    2015-04-01

    Fifty-eight sediment samples were collected from the Kaohsiung Harbor (Taiwan) for analyses of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT), using gas chromatography/flame photometric detector (GC/FPD). The concentration of total butyltins (ΣBTs), sum of MBT, DBT, and TBT, varied from 3.9 to 158.5 ng Sn/g dw in sediment samples with TBT being the major component of the sediment samples, except for the vicinity of the Love River mouth where MBT was the most abundant BT compound (a proportion of over 57%). Based on the BTs concentration, distribution, composition and correlations, the sources of BTs found in harbor sediments are shipping activities, and TBT is the main pollutant; the estuary (i.e. Love River) has been the anthropogenic source of MBT from upstream inputs. Influences of TBT on aquatic organisms are evaluated using the toxicity guidelines proposed by the US EPA (US Environmental Protection Agency) and the ACCI (assessment class criterion for imposex) proposed by OSPAR (Oslo and Paris Commission). The evaluation shows that the TBT contained in the sediment at Kaohsiung Harbor is likely to have a negative influence at ACCI class C because gastropods present imposex and TBT levels are above ecotoxicological assessment criteria (EAC) limits.

  2. Contaminants of concern in Dutch marine harbor sediments.

    PubMed

    Stronkhorst, J; van Hattum, B

    2003-10-01

    The status of the contamination of Dutch marine harbor sediments was reevaluated after a period in which emissions from point sources had been greatly reduced. Data on sediment chemistry from 1999 and 2000 were assessed against screening levels (SLs) selected from available sediment quality guidelines and representing a low probability of adverse biological effects. This yielded a ranking of the environmental hazard of 22 contaminants. Most of the sediments were silty material; every year 15 to 25 million m3 of such material is dredged from Dutch harbors. Some 34% of the volume exceeded one or more SLs. The contaminants of concern were tributyltin (TBT), mineral oil (petroleum hydrocarbons), polychlorinated biphenyls (PCBs), and mercury. The PCB and mercury contamination is the legacy of historic inputs; the TBT and mineral oil contamination is related to present-day shipping activity. Concentrations of trace metals, rare earth elements, organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were low and apparently of minor environmental concern. It is concluded that the risk assessment would be improved by laboratory testing of adverse biological effects.

  3. Comprehensive Condition Survey and Storm Waves, Circulation, and Sediment Study, Dana Point Harbor, California

    DTIC Science & Technology

    2014-12-01

    to investigate wave, flow, sediment transport, and permeable breakwaters with rocky outcrop bottom at Dana Point Harbor, as a part of the harbor...current and sediment seepage through permeable breakwaters, and circulation in the harbor under combined wave, tide, and flow conditions. Permeable ...75 Figure 56. Sketch of wave transmission and flow penetration through a permeable structure

  4. Chemical and biological availability of hydrocarbons in urban harbor sediments

    USGS Publications Warehouse

    LeBlanc, L.A.; Brownawell, Bruce J.

    2002-01-01

    The degradation of saturated and aromatic hydrocarbons was studied in batch slurry experiments conducted with field-aged sediments, highly impacted by hydrocarbon pollution. Experiments focused on examining the effects of desorption limitations to hydrocarbon mineralization and degradation. Degradation of PAH (e.g., naphthalene, fluorene, acenaphthene) and saturated hydrocarbons was examined in field-aged sediments collected from four sites in greater NY Harbor and western Long Island Sound. The sites were Rikers Island in far western Long Island Sound, Williamsburg Bridge in the East River, Shooters Island in the Arthur Kill, and the Kill Van Kull off Bayonne, New Jersey. Patterns of hydrocarbon desorption and degradation in weathered sediments were complicated by the mixed combustion and oil-derived hydrocarbon sources, and differed markedly from patterns seen in sediments following an oil spill. Rates of degradation in experiments with spiked sediments, especially over short timescales, did not appear to be limited by rates of desorption. This is an abstract of a paper presented at the 224th ACS National Meeting (Boston, MA 8/18-22/2002).

  5. Charleston Harbor, SC, Regional Sediment Management Study; Beneficial Use of Dredged Material through Nearshore Placement

    DTIC Science & Technology

    2017-05-01

    ER D C/ CH L TR -1 7- 7 Regional Sediment Management (RSM) Program Charleston Harbor, SC, Regional Sediment Management Study ...Management Study ; Beneficial Use of Dredged Material through Nearshore Placement Layla R. Kashlan U.S. Army Engineer District, Wilmington P.O. Box...454632, “Charleston Harbor, SC; Regional Sediment Management Study ” ERDC/CHL TR-17-7 ii Abstract The 2015 Charleston Harbor, SC, final

  6. Evaluation of older bay mud sediment from Richmond Harbor, California

    SciTech Connect

    Pinza, M.R.; Mayhew, H.L.; Word, J.Q.

    1996-09-01

    The older, bay mud (OBM) unit predates modem man and could act as a barrier to the downward transport of contaminants from the younger bay mud (YBM) because of its hard-packed consistency. However, its chemical and biological nature have not been well characterized. Battelle/Marine Sciences Laboratory (MSL) conducted three independent studies of OBM sediment in January 1993, January 1994, and October 1994. These studies evaluated potential chemical contamination and biological effects of OBM that could occur as a result of dredging and disposal activities. These evaluations were performed by conducting chemical analysis, solid-phase toxicity tests, suspended- particulate-phase (SPP) toxicity tests, and bioaccumulation tests on the OBM sediment. If the sediment chemistry and toxicity results showed no or minimal contamination and toxicological responses, then either the OBM could be left exposed in Richmond Harbor after dredging the YBM without leaving a source of contamination, or if the project depths necessitate, the OBM would be acceptable for disposal at an appropriate disposal site.

  7. Identification of acute toxicants in New Bedford Harbor sediments

    SciTech Connect

    Ho, K.T.; McKinney, R.A.; Kuhn, A.; Pelletier, M.C.; Burgess, R.M.

    1997-03-01

    New Bedford Harbor (NBH) is a marine Superfund site contaminated with high concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and metals. Experiments were conducted to determine the causal toxic agent(s) in pore waters from New Bedford Harbor sediments to amphipods and mysid shrimp. Chemical manipulations to characterize toxicity revealed that pore-water toxicity was organic in nature. Fractionation and subsequent mass spectral identification of peaks in the toxic fraction indicated that PCBs. PAHs, and unknown compounds were present. Comparisons of PAH LC50s and PAH concentrations in this fraction indicated that the toxicity was not due to PAHs because the PAH concentrations were much lower than the reported PAH LC50s. One unknown peak was positively identified as bis(2-ethylhexyl) phthalate, and the other tentatively identified as pyrazole. Toxicity tests and comparison of toxicity in the blank and toxic fractions eliminated the two unknowns as toxic causal agents. The authors determined the range of PCB LC50s to fall between 10 and 110 ppb for Mysidopsis bahia and Ampelisca abdita. Concentrations of PCBs for the toxic fractions ranged from 12 to 27 ppb. This range falls within the observed PCB LC50s for M. bahia and A. abdita. Based upon these PCB concentrations, they concluded that PCBs were the acute toxic agents in NBH pore waters. Other compounds in the toxic fractions, or compounds that coeluted and were undistinguished from PCBs had minor contributions to the measured toxicity.

  8. Sedimentation and chronology of heavy metal pollution in Oslo harbor, Norway.

    PubMed

    Lepland, Aivo; Andersen, Thorbjørn J; Lepland, Aave; Arp, Hans Peter H; Alve, Elisabeth; Breedveld, Gijs D; Rindby, Anders

    2010-09-01

    Stratigraphic profiles of Cu, Cd and Hg in ten sediment cores from the Oslo harbor, Norway, combined with results of radiometric dating demonstrate that pollution by these metals peaked between 1940 and 1970. Dating results indicate that Hg discharges peaked between 1940 and 1950, Cd reached maximum ca. 1955-1960, and Cu has the highest concentration in sediment interval corresponding to ca. 1970. Geochemical profiles and maxima of Cu, Cd and Hg concentrations can be used as chronostratigraphic markers for sediment cores from the Oslo harbor. Acoustic backscatter and sediment core data indicate that propeller wash affects the seabed in the Oslo harbor. The propeller-induced turbulence causes erosion, and in places exposes and remobilizes contaminated sediments that accumulated in the harbor during previous decades. Such re-exposure of contaminated sediments could be detrimental to local ecosystems and offset remediation efforts, warranting further impact studies and potential mitigation strategies to prevent redistribution.

  9. Ecological risk assessment of trace metal accumulation in sediments of Veraval Harbor, Gujarat, Arabian Sea.

    PubMed

    Sundararajan, S; Khadanga, Mukunda Kesari; Kumar, J Prince Prakash Jeba; Raghumaran, S; Vijaya, R; Jena, Basanta Kumar

    2017-01-15

    In this study, different types of indices were used to assess the ecological risk of trace metal contamination in sediments on the basis of sediment quality guidelines at Veraval Fishery Harbor. Sediment samples were collected from three sectors in pre-, post-, and monsoon seasons in 2006. Trace metal concentrations were higher in the inner sector during post-monsoon, and it showed the highest statistical significance (p<0.01) among the stations. Pollution load index was higher than unity, indicating alternation by effluent discharge from industries. Enrichment factor and geo-accumulation index showed that Cd, Pb, and Zn were enriched in the northern part of the harbor and Pb had accumulated in the harbor sediment. The ecological risk assessment index revealed that Ni, Zn, and Pb were higher than the effect range median values, indicating their potential toxicity to the aquatic environment in the Veraval Harbor. Hence, the harbor is dominated by anthropogenic activities rather than natural process.

  10. Sediment porewater partitioning of polycyclic aromatic hydrocarbons in three cores from Boston Harbor, Massachusetts

    USGS Publications Warehouse

    Mcgroddy, S.E.; Farrington, J.W.

    1995-01-01

    Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in sediments and porewaters isolated from three cores from Boston Harbor, MA. Measured porewater PAH concentrations were significantly lower than the concentrations predicted by two- and three-phase equilibrium partitioning models. We hypothesize that only a fraction of the measured sediment PAH concentrations was available to partition rapidly into sediment porewaters. ?? 1995 American Chemical Society.

  11. Aliphatic Hydrocarbons in Surface Sediments of Willapa Bay and Grays Harbor, Washington

    USGS Publications Warehouse

    Rapp, J.B.; Kvenvolden, K.A.; Clifton, H.E.

    1982-01-01

    Willapa Bay and Grays Harbor are two adjacent estuaries along the coast of Washington state. Willapa Bay is a recreational area minimally affected by industry; Grays Harbor, on the other hand, is moderately industrialized. Aliphatic hydrocarbons in surface sediments from these two estuaries reflect the differences in human activities. For example, the mean concentration of aliphatic hydrocarbons for seven stations in Willapa Bay is 1,000 ?g/g (relative to organic carbon) while in Grays Harbor this mean concentration for six stations is 1,900 ?g/g. The difference is attributed mainly to the greater urban and industrial pollution in Grays Harbor. The gas chromatographic records of aliphatic hydrocarbons also reflect the extent of hydrocarbon pollution by the presence of a chromatographically unresolved mixture of hydrocarbons. This kind of mixture is more evident in sediments from Grays Harbor, and in both estuaries it is more concentrated in sediments collected nearest to urban centers.

  12. 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. Thomas; 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

  13. Metals in sediments and fish from Sea Lots and Point Lisas harbors, Trinidad and Tobago

    USGS Publications Warehouse

    Mohammed, Azad; May, Thomas; Echols, Kathy; Walther, Mike; Manoo, Anton; Maraj, Dexter; Agard, John; Orazio, Carl

    2012-01-01

    Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from Sea Lots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. The most dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at Sea Lots (Al-39420 μg/g; Fe-45640 μg/g; Zn-245 μg/g), when compared to sediments from Point Lisas (Al-11936 μg/g; Fe-30171 μg/g; Zn-69 μg/g) and Caroni (Al-0400 μg/g; Fe-19000 μg/g; Zn-32 μg/g), High concentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal concentrations in fish tissue showed significant correlation with sediment metals concentration, which suggests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had a bioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for these metals.

  14. Metals in sediments and fish from Sea Lots and Point Lisas harbors, Trinidad and Tobago

    USGS Publications Warehouse

    Mohammed, Azad; May, Thomas; Echols, Kathy; Walther, Mike; Manoo, Anton; Maraj, Dexter; Agard, John; Orazio, Carl

    2012-01-01

    Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from Sea Lots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. The most dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at Sea Lots (Al-39420 μg/g; Fe-45640 μg/g; Zn-245 μg/g), when compared to sediments from Point Lisas (Al-11936 μg/g; Fe-30171 μg/g; Zn-69 μg/g) and Caroni (Al-0400 μg/g; Fe-19000 μg/g; Zn-32 μg/g), High concentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal concentrations in fish tissue showed significant correlation with sediment metals concentration, which suggests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had a bioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for these metals.

  15. Metals in sediments and fish from Sea Lots and Point Lisas Harbors, Trinidad and Tobago

    USGS Publications Warehouse

    Mohammed, A.; May, T.; Echols, K.; Walther, M.; Manoo, A.; Maraj, D.; Agard, J.; Orazio, C.

    2012-01-01

    Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from Sea Lots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. The most dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at Sea Lots (Al-39420 ??g/g; Fe-45640 ??g/g; Zn-245 ??g/g), when compared to sediments from Point Lisas (Al-11936 ??g/g; Fe-30171 ??g/g; Zn-69 ??g/g) and Caroni (Al-0400 ??g/g; Fe-19000 ??g/g; Zn-32 ??g/g), High concentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal concentrations in fish tissue showed significant correlation with sediment metals concentration, which suggests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had a bioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for these metals. ?? 2011 Elsevier Ltd.

  16. Effects of sediment remediation on reproductive function in English sole from Eagle Harbor, WA

    SciTech Connect

    Johnson, L.L.; Sol, S.Y.; Lomax, D.P.; Myers, M.S.; Collier, T.K.

    1995-12-31

    Eagle Harbor, near Bainbridge Island in Puget Sound, WA is currently designated as an EPA Superfund site because of high levels of creosote-derived PAHs in the sediments. In 1986--88, the authors conducted a series of studies evaluating reproductive function in English sole from Eagle Harbor. These studies showed that only about 60% of adult female sole from the Eagle Harbor site entered vitellogenesis, in comparison to 80--90% of females of comparable age and size from minimally contaminated Puget Sound sites. Eagle Harbor fish also exhibited reduced spawning success and lowered egg viability in comparison to fish from unpolluted sites. Both types of reproductive function were associated with depressed plasma levels of reproductive steroids (e.g. 17-B estradiol) in Eagle Harbor fish. In September of 1993 the EPA began placement of a cap of uncontaminated sediment over the most contaminated portions of Eagle Harbor, as a means of providing clean habitat for benthic organisms and reducing risk from the contaminants contained in the sediments. Since the time of capping, the authors have been monitoring reproductive development in English sole and related benthic flatfish to determine whether this restoration will result in improved reproductive success in the resident flatfish of Eagle Harbor. Preliminary results indicate that the proportion of maturing females has increased to approximately 75%. Other reproductive parameters, including plasma steroid hormone concentration and ovarian atresia, are currently being assessed. Nonetheless, the initial data suggest that sediment remediation is associated with improved reproductive function in Eagle Harbor bottom fish.

  17. Effects of deposition of heavy-metal-polluted harbor mud on microbial diversity and metal resistance in sandy marine sediments.

    PubMed

    Toes, Ann-Charlotte M; Finke, Niko; Kuenen, J Gijs; Muyzer, Gerard

    2008-10-01

    Deposition of dredged harbor sediments in relatively undisturbed ecosystems is often considered a viable option for confinement of pollutants and possible natural attenuation. This study investigated the effects of deposition of heavy-metal-polluted sludge on the microbial diversity of sandy sediments during 12 months of mesocosm incubation. Geochemical analyses showed an initial increase in pore-water metal concentrations, which subsided after 3 months of incubation. No influence of the deposited sediment was observed in denaturing gradient gel electrophoresis (DGGE) profiles of bacterial 16S rRNA genes, whereas a minor, transient impact on the archaeal community was revealed. Phylogenetic analyses of bacterial 16S rRNA clone libraries showed an abundance of members of the Flavobacteriaceae, the alpha- and gamma-Proteobacteria, in both the muddy and the sandy sediments. Despite the finding that some groups of clones were shared between the metal-impacted sandy sediment and the harbor control, comparative analyses showed that the two sediments were significantly different in community composition. Consequences of redeposition of metal-polluted sediment were primarily underlined with cultivation-dependent techniques. Toxicity tests showed that the percentage of Cd- and Cu-tolerant aerobic heterotrophs was highest among isolates from the sandy sediment with metal-polluted mud on top.

  18. Metal concentrations in surface sediments of Boston Harbor: Changes with time

    USGS Publications Warehouse

    Bothner, Michael H.; Buchholtz ten Brink, M.; Manheim, F. T.

    1998-01-01

    The concentrations of metals in surface sediments of Boston Harbor have decreased during the period 1977–1993. This conclusion is supported by analysis of: (1) surface sediments collected at monitoring stations in the outer harbor between 1977 and 1993; (2) metal concentration profiles in sediment cores from depositional areas of the harbor; and (3) historical data from a contaminated-sediment database, which includes information on metal and organic contaminants and sediment texture. The background and matrix-corrected concentrations of lead (Pb) measured in the surficial layer (0–2 cm) of cores decreased by an average of 46%±12% among four locations in the outer harbor during the 16 y period. Chromium (Cr), copper (Cu), mercury (Hg), silver (Ag), and zinc (Zn) exhibited similar trends. Results from our sediment sampling are supported by historical data that were compiled from diverse sources into a regional sediment database. This sediment database contains approximately 3000 samples; of these, about 460 samples were collected and analyzed for Cu, Hg, or Zn and many other sediment parameters in Boston Harbor surface sediments between 1971–1993. The database indicates that the concentrations of these three metals also decreased with time in Boston’s Inner Harbor. The decreases in metal concentrations that are observed in more recent years parallel a general decrease in the flux of metals to the harbor, implemented by: (1) ending the sewage sludge discharge to the Harbor in December, 1991; (2) greater source reduction (e.g. recovery of silver from photographic processing) and closing or moving of industries; (3) improvements in wastewater handling and sewage treatment; and (4) diminishing use of lead in gasoline beginning about 1973. Despite the general decrease in metal concentrations in Boston Harbor surface sediments, the concentrations of Ag and Hg measured at some outer harbor stations in 1993 were still at, or above, the level associated with

  19. A TOXICITY IDENTIFICATION EVALUATION OF SILTY MARINE HARBOR SEDIMENTS TO CHARACTERIZE PERSISTENT AND NON-PERSISTENT CONSTITUENTS

    EPA Science Inventory

    Sediment toxicity in silty marine harbor sediments is frequently dominated by ammonia or sulfide, leaving the adverse effects of persistent toxic substances unnoticed. To investigate the latter, we subjected interstitial water from three contaminated silty sediments to toxicity i...

  20. A TOXICITY IDENTIFICATION EVALUATION OF SILTY MARINE HARBOR SEDIMENTS TO CHARACTERIZE PERSISTENT AND NON-PERSISTENT CONSTITUENTS

    EPA Science Inventory

    Sediment toxicity in silty marine harbor sediments is frequently dominated by ammonia or sulfide, leaving the adverse effects of persistent toxic substances unnoticed. To investigate the latter, we subjected interstitial water from three contaminated silty sediments to toxicity i...

  1. Assessment of trace element geochemistry of Hampton Roads harbor and lower Chesapeake Bay area sediments

    NASA Astrophysics Data System (ADS)

    Rule, Joseph H.

    1986-12-01

    Acid extractable Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb. and Zn were determined in sediments from the Inner Virginia Shelf, and from shipping channels in the lower Chesapeake Bay and Hampton Roads, Virginia, harbor system. Data were evaluated by a variety of techniques Levels of Cd, Cu, Pb, and Zn exceeded average crustal abundances for most of the study sites. Cumulative frequency curves suggested that there were two major populations for all metals and perhaps a third and smaller, one for Cd, Cr, and Mn Plots of metal vs Fe indicated no anthropogenic inputs of metals for shelf and Chesapeake Bay channel sites, but suggested anthropogenic influences for all metals in several of the inshore sites. Enrichment factor calculations showed enrichment of Cd, Pb, and Zn with respect to average crustal abundances for all sites and of Cu for the industrial harbor system. A recommendation of this study for evaluation of environmental geochemical metals data is to utilize mean concentrations, cumulative frequency plots, and metal vs Fe and/or enrichment factor calculations when evaluating the pollution status of sediments.

  2. Environment-dependent distribution of the sediment nifH-harboring microbiota in the Northern South China Sea.

    PubMed

    Dang, Hongyue; Yang, Jinying; Li, Jing; Luan, Xiwu; Zhang, Yunbo; Gu, Guizhou; Xue, Rongrong; Zong, Mingyue; Klotz, Martin G

    2013-01-01

    The South China Sea (SCS), the largest marginal sea in the Western Pacific Ocean, is a huge oligotrophic water body with very limited influx of nitrogenous nutrients. This suggests that sediment microbial N(2) fixation plays an important role in the production of bioavailable nitrogen. To test the molecular underpinning of this hypothesis, the diversity, abundance, biogeographical distribution, and community structure of the sediment diazotrophic microbiota were investigated at 12 sampling sites, including estuarine, coastal, offshore, deep-sea, and methane hydrate reservoirs or their prospective areas by targeting nifH and some other functional biomarker genes. Diverse and novel nifH sequences were obtained, significantly extending the evolutionary complexity of extant nifH genes. Statistical analyses indicate that sediment in situ temperature is the most significant environmental factor influencing the abundance, community structure, and spatial distribution of the sediment nifH-harboring microbial assemblages in the northern SCS (nSCS). The significantly positive correlation of the sediment pore water NH(4)(+) concentration with the nifH gene abundance suggests that the nSCS sediment nifH-harboring microbiota is active in N(2) fixation and NH(4)(+) production. Several other environmental factors, including sediment pore water PO(4)(3-) concentration, sediment organic carbon, nitrogen and phosphorus levels, etc., are also important in influencing the community structure, spatial distribution, or abundance of the nifH-harboring microbial assemblages. We also confirmed that the nifH genes encoded by archaeal diazotrophs in the ANME-2c subgroup occur exclusively in the deep-sea methane seep areas, providing for the possibility to develop ANME-2c nifH genes as a diagnostic tool for deep-sea methane hydrate reservoir discovery.

  3. Environment-Dependent Distribution of the Sediment nifH-Harboring Microbiota in the Northern South China Sea

    PubMed Central

    Yang, Jinying; Li, Jing; Luan, Xiwu; Zhang, Yunbo; Gu, Guizhou; Xue, Rongrong; Zong, Mingyue; Klotz, Martin G.

    2013-01-01

    The South China Sea (SCS), the largest marginal sea in the Western Pacific Ocean, is a huge oligotrophic water body with very limited influx of nitrogenous nutrients. This suggests that sediment microbial N2 fixation plays an important role in the production of bioavailable nitrogen. To test the molecular underpinning of this hypothesis, the diversity, abundance, biogeographical distribution, and community structure of the sediment diazotrophic microbiota were investigated at 12 sampling sites, including estuarine, coastal, offshore, deep-sea, and methane hydrate reservoirs or their prospective areas by targeting nifH and some other functional biomarker genes. Diverse and novel nifH sequences were obtained, significantly extending the evolutionary complexity of extant nifH genes. Statistical analyses indicate that sediment in situ temperature is the most significant environmental factor influencing the abundance, community structure, and spatial distribution of the sediment nifH-harboring microbial assemblages in the northern SCS (nSCS). The significantly positive correlation of the sediment pore water NH4+ concentration with the nifH gene abundance suggests that the nSCS sediment nifH-harboring microbiota is active in N2 fixation and NH4+ production. Several other environmental factors, including sediment pore water PO43− concentration, sediment organic carbon, nitrogen and phosphorus levels, etc., are also important in influencing the community structure, spatial distribution, or abundance of the nifH-harboring microbial assemblages. We also confirmed that the nifH genes encoded by archaeal diazotrophs in the ANME-2c subgroup occur exclusively in the deep-sea methane seep areas, providing for the possibility to develop ANME-2c nifH genes as a diagnostic tool for deep-sea methane hydrate reservoir discovery. PMID:23064334

  4. Diversity and Distribution of Sediment ureC-Harboring Microbiota in the Northern South China Sea.

    NASA Astrophysics Data System (ADS)

    Wei, X.

    2016-02-01

    Urea is an important component of marine nitrogen cycle. It's hydrolyzed by microbes for nitrogen assimilation or energy metabolism via ammonia oxidation. Urea hydrolysis also significantly influences the sediment-to-seawater flux of nitrogenous nutrients. So far, studies of marine ureolytic microorganisms mainly focused on seawater environments, yet little is known about the diversity, community structure and controlling environmental factors of ureolytic microorganisms in marine sediment environments. In the current study, we investigated the diversity, abundance, composition, activity, biogeographical distribution and controlling environmental factors of putatively ureolytic microorganisms from 12 sampling stations of the northern South China Sea, including distinct estuarine, coastal, offshore, and deep-sea habitats, using bacterial and archaea ureC genes as sequence biomarkers. Diverse archaeal and bacterial ureC gene sequences were obtained and sediment ureolytic activities were identified in all the sampling environments. Key environmental factors that may shape the community structure and spatial distribution of the ureC-harboring bacteria and archaea have been identified. Our results demonstrated that urea utilizing microorganisms may play an important role in marine nitrogen cycling in diverse sediment environments.

  5. Investigation of Sediment Strength Characteristics in Approaches to Boston Harbor Using STING Penetrometer

    DTIC Science & Technology

    2014-09-17

    Unclassified Unlimited Unclassified Unlimited Unclassified Unlimited Unclassified Unlimited Seafloor strength Impact burial STING 58 Andrei Abelev (202) 404...1107 This report discusses results of two series of STING penetrometer measurements of seafloor sediment strength in areas of Boston Harbor approach... seafloor sediment conditions. Normally, three to four drops per location were performed. Selection of the STING foot diameter may be guided by

  6. Pollutant Concentrations and Toxic Effects on the Red Alga Ceramium tenuicorne of Sediments from Natural Harbors and Small Boat Harbors on the West Coast of Sweden.

    PubMed

    Eklund, Britta; Hansson, Tomas; Bengtsson, Henrik; Eriksson Wiklund, Ann-Kristin

    2016-04-01

    This investigation set out to analyze the toxicity of surface sediments in a number of natural harbors and small boat harbors on the west coast of Sweden. This was done with the growth inhibition method with Ceramium tenuicorne. Also, concentrations of copper (Cu), lead (Pb), zinc (Zn), irgarol, organotin compounds, and polycyclic aromatic hydrocarbons (PAHs) in the sediments were analyzed. The small boat harbors were heavily polluted by Cu, Zn, butyltins, and PAHs, and to a lesser extent by Pb. The Cu, Pb, Zn, and butyltins probably originated from their past and/or present use in antifouling paints, whereas the PAHs probably had multiple sources, including boat motor exhausts. The measured toxicity of the sediment was generally related to their Cu, Zn, and butyltin content, although other toxic substances than those analyzed here probably contributed to the toxicity in some of the harbors. The natural harbor sediments contained less pollutants and were less toxic than the small boat harbor sediments. Nevertheless, our data indicate that the boating pressure today may be high enough to produce toxic effects even in natural harbors in pristine areas. The strongest relationship between toxicity and the major pollutants was obtained when the sediment toxicity was expressed as gram wet weight per liter compared with gram dry weight per liter and gram total organic carbon per liter. Hence, for pollutants that can be elutriated with natural sea water, sediment toxicity expressed as gram wet weight per liter appears preferable.

  7. Sediment Budget on the Indiana Shore at Burns Harbor, Lake Michigan

    DTIC Science & Technology

    2015-05-15

    146 20/03/2015 16 pp 5 Sediments and Littoral Transport Geomorphically, much of the south shore of Lake Michigan consists of sandy beach with...1 SEDIMENT BUDGET ON THE INDIANA SHORE AT BURNS HARBOR, LAKE MICHIGAN ANDREW MORANG1, ASHLEY E. FREY1, DAVID F. BUCARO2, AND SARA BRODZINSKY2...environment. One element in implementing RSM along the Lake Michigan shore was to develop a sediment budget for the following purposes: • Gaining a better

  8. Waves, Hydrodynamics and Sediment Transport Modeling at Grays Harbor, WA

    DTIC Science & Technology

    2010-12-01

    environments and sediment types. For instance, a transport method developed for cobbles and boulders in an alpine stream is not likely to correctly...flumes are available to parameterize site-specific cohesive sediment erosion algorithms. The majority of these devices operate over only a small...range of shear stress (ɚ Pa) and only measure surface sediment erosion. Sedflume is an erosion device with capability to impose bed stresses in the

  9. PCB and PAH speciation among particle types in contaminated harbor sediments and effects on PAH bioavailability.

    PubMed

    Ghosh, Upal; Zimmerman, John R; Luthy, Richard G

    2003-05-15

    This research provides particle-scale understanding of PCB and PAH distribution in sediments obtained from three urban locations in the United States: Hunters Point, CA; Milwaukee Harbor, WI; and Harbor Point, NY. The sediments comprised mineral grains (primarily sand, silt, and clays) and carbonaceous particles (primarily coal, coke, charcoal, pitch, cenospheres, and wood). The carbonaceous sediment fractions were separated from the mineral fractions based on their lower density and were identified by petrographic analysis. In all three sediments, carbonaceous particles contributed 5-7% of the total mass and 60-90% of the PCBs and PAHs. The production of carbonaceous particles is not known to be associated with PCB contamination, and it is very unlikely that these particles can be the source of PCBs in the environment Thus, it appears that carbonaceous particles preferentially accumulate PCBs acting as sorbents in the aqueous environment if PCBs are released directly to the sediment or if deposited as airborne soot particles. Aerobic bioslurry treatment resulted in negligible PAH loss from the carbonaceous coal-derived material in Milwaukee Harbor sediment but resulted in 80% of the PAHs being removed from carbonaceous particles in Harbor Point sediment. Microscale PAH extraction and analysis revealed that PAHs in Harbor Point sediment were associated mainly with coal tar pitch residue. PAHs present in semisolid coal tar pitch are more bioavailable than PAHs sorbed on carbonaceous particles such as coal, coke, charcoal, and cenosphere. Results of this study illustrate the importance of understanding particle-scale association of hydrophobic organic contaminants for explaining bioavailability differences among sediments.

  10. The dynamics of fine-grain sediment dredged from Santa Cruz Harbor

    USGS Publications Warehouse

    Storlazzi, Curt D.; Conaway, Christopher H.; Presto, M. Katherine; Logan, Joshua B.; Cronin, Katherine; van Ormondt, Maarten; Lescinski, Jamie; Harden, E. Lynne; Lacy, Jessica R.; Tonnon, Pieter K.

    2011-01-01

    In the fall and early winter of 2009, a demonstration project was done at Santa Cruz Harbor, California, to determine if 450 m3/day of predominantly (71 percent) mud-sized sediment could be dredged from the inner portion of the harbor and discharged to the coastal ocean without significant impacts to the beach and inner shelf. During the project, more than 7600 m3 of sediment (~5400 m3 of fine-grain material) was dredged during 17 days and discharged approximately 60 m offshore of the harbor at a depth of 2 m on the inner shelf. The U.S. Geological Survey's Pacific Coastal and Marine Science Center was funded by the U.S. Army Corps of Engineers and the Santa Cruz Port District to do an integrated mapping and process study to investigate the fate of the mud-sized sediment dredged from the inner portion of Santa Cruz Harbor and to determine if any of the fine-grain material settled out on the shoreline and/or inner shelf during the fall and early winter of 2009. This was done by collecting highresolution oceanographic and sediment geochemical measurements along the shoreline and on the continental shelf of northern Monterey Bay to monitor the fine-grain sediment dredged from Santa Cruz Harbor and discharged onto the inner shelf. These in place measurements, in conjunction with beach, water column, and seabed surveys, were used as boundary and calibration information for a three-dimensional numerical circulation and sediment dynamics model to better understand the fate of the fine-grain sediment dredged from Santa Cruz Harbor and the potential consequences of disposing this type of material on the beach and on the northern Monterey Bay continental shelf.

  11. Trace metal levels in sediments of Pearl Harbor (Hawaii)

    SciTech Connect

    Ashwood, T.L.; Olsen, C.R.; Larsen, I.L.; Tamura, T.

    1986-09-01

    This study was conducted to measure the distribution of lead and other trace metals in the sediments of Pearl Harbon (Hawaii) to determine whether paint chips from vessels of the US Navy's Inactive Fleet have affected the environmental quality of Middle Loch. Sediment cores (ranging from 0.5 to 3.0 m long) were collected from Middle Loch near the Naval Inactive Ships Maintenance Facility and in an area of West Loch that is relatively isolated and unaffected by naval operations. Concentrations of copper, lead, and zinc averaged 180 ..mu..g/g, 49 ..mu..g/g, and 272 ..mu..g/g, respectively, in recent Middle Loch sediments. These concentrations are significantly higher than those in either historical Middle Loch sediments or recent West Loch sediments. However, except for lead, the concentrations in recent Middle Loch sediments are similar to those of older Middle Loch sediments, which indicates that the increase in trace metal contamination began before the onset of Inactive Fleet operations (about 1946). Increased trace metal levels in recent Middle Loch sediments might be expected to result from two potential sources: (1) sewage discharges and (2) paint from inactive vessels. Since paint contains elevated levels of lead and zinc but little copper, the elevated copper levels in Middle Loch sediments tend to implicate sewage as the source of trace metal contamination. Moreover, the lead:zinc ratio of recent Middle Loch sediments (0.18:1) is a factor of 10 lower than that measured in paint (2.1:1), and the Middle Loch lead:zinc ratio is not significantly greater than that measured in recent West Loch sediments (0.21:1). Hence, we suggest that sewage rather than paint is the major source of trace metal contamination of Middle Loch. This is consistent with the findings of a previous study by US navy personnel.

  12. Geochemical investigation of a sediment core from the Trajan basin at Portus, the harbor of ancient Rome

    NASA Astrophysics Data System (ADS)

    Delile, H.; Mazzini, I.; Blichert-Toft, J.; Goiran, J. P.; Arnaud-Godet, F.; Salomon, F.; Albarède, F.

    2014-03-01

    From the 1st century AD and for the duration of the Roman Empire, the Portus complex was the main harbor of Rome. Its location on the Tiber delta next to the Tyrrhenian Sea produced rapid environmental changes that, together with historical vicissitudes, largely determined the fate of the harbor. We have assembled data on the mineralogy, sedimentology, geochemistry, and ostracod populations of a sediment core drilled in the access channel of the hexagonal basin of Trajan, with the expectation that such a combined data set will shed new light on how the connections of the inland Trajan basin with the Tiber river, the earlier Claudius harbor on the nearby shoreline, and the sea evolved through the centuries. The data define four distinct periods which geochemistry characterizes by different conditions of salinity and oxygenation. These in turn can be related to historical periods and events by means of 14C data. The early Imperial Period was dominated by input of well-oxygenated freshwater from the Tiber. During the Late Empire, harbor water became relatively more influenced by seawater and increasingly oxygen deficient, which attests to a decommissioning of the Canale Trasverso connecting the harbor to the Tiber. The strong anthropogenic signal, which is visible very clearly in geochemical parameters, attests to the human occupation of the harbor area up to the Early Middle Ages, when human activity was brought to an abrupt end. The simultaneous use in this study of multiple complementary tracers has allowed for the sedimentary sources of the different classes of particles in the harbor basin to be identified and assigned to either the freshwater supply from the Canale Trasverso or the seawater of the Claudius harbor.

  13. Utilization of Savannah Harbor river sediment as the primary raw material in production of fired brick.

    PubMed

    Mezencevova, Andrea; Yeboah, Nortey N; Burns, Susan E; Kahn, Lawrence F; Kurtis, Kimberly E

    2012-12-30

    A laboratory-scale study was conducted to assess the feasibility of the production of fired bricks from sediments dredged from the Savannah Harbor (Savannah, GA, USA). The dredged sediment was used as the sole raw material, or as a 50% replacement for natural brick-making clay. Sediment bricks were prepared using the stiff mud extrusion process from raw mixes consisted of 100% dredged sediment, or 50% dredged sediment and 50% brick clay. The bricks were fired at temperatures between 900 and 1000 °C. Physical and mechanical properties of the dredged sediment brick were found to generally comply with ASTM criteria for building brick. Water absorption of the dredged sediment bricks was in compliance with the criteria for brick graded for severe (SW) or moderate (MW) weathering. Compressive strength of 100% dredged sediment bricks ranged from 8.3 to 11.7 MPa; the bricks sintered at 1000 °C met the requirements for negligible weathering (NW) building brick. Mixing the dredged sediment with natural clay resulted in an increase of the compressive strength. The compressive strength of the sediment-clay bricks fired at 1000 °C was 29.4 MPa, thus meeting the ASTM requirements for the SW grade building brick. Results of this study demonstrate that production of fired bricks is a promising and achievable productive reuse alternative for Savannah Harbor dredged sediments.

  14. Bioremediation of contaminated harbor sediments. 2: Monitoring of contaminant degradation

    SciTech Connect

    Vanderhaegen, B.; De Brabandere, J.; Dumon, G.; Verstraete, W.

    1995-12-31

    A 3 phase project involving bench, pilot and full scale application aimed at bioremediation of polycyclic aromatic hydrocarbons (PAH), mineral oil and tributyltin (TBT) contaminated sediments. On bench scale, biodegradation of PAH was monitored in 1-liter aerobic completely mixed reactors. The effect of adding microbial associations, surfactants and nutrients was monitored. Three parallel tests were set up: one monitored by means of {sup 14}C-labelled naphthalene and benzo(a)pyrene, the other by GC-MSD analyses and a third by respirometry and HPLC. A shift from dichloromethane extractable {sup 14}C to non-extractable {sup 14}C for the labelled molecules was observed. Further analyses revealed that the nonextractable {sup 14}C was associated with the humines. The amount of {sup 14}C recovered as {sup 14}C-CO{sub 2} was 10% for benzo(a)pyrene and 54% for naphthalene. The results were not influenced by adding microbial inocula. Results of GC-MSD-measurements indicated an overall removal efficiency of 70% after 7 weeks (half-life: 1 month). Supplementary addition of bacteria sometimes gave slightly better results. During the pilot scale test, a systematic difference between GC-MSD and HPLC was detected. GC-MSD gave a bigger response on low molecular weight PAH. HPLC revealed higher concentrations for more complex PAH. Overall, GC-MSD was evaluated as the most valuable method. The experiment confirmed the bench scale kinetics. After 5 weeks the PAH-concentration remained constant. The overall removal efficiency was 70 to 90% after 5 months. Tributyltin and mineral oil were mineralized with about 70% (half-life: 15 weeks) and 90% respectively.

  15. Anaerobic, sulfate-dependent degradation of polycyclic aromatic hydrocarbons in petroleum-contaminated harbor sediment.

    PubMed

    Rothermich, Mary M; Hayes, Lory A; Lovley, Derek R

    2002-11-15

    It has previously been demonstrated that [14C]-labeled polycyclic aromatic hydrocarbons (PAHs) can be oxidized to 14CO2 in anoxic, PAH-contaminated, marine harbor sediments in which sulfate reduction is the terminal electron-accepting process. However, it has not previously been determined whether this degradation of [14C]-PAHs accurately reflects the degradation of the in situ pools of contaminant PAHs. In coal tar-contaminated sediments from Boston Harbor, [14C]-naphthalene was readily oxidized to 14CO2, but, after 95 d of incubation under anaerobic conditions, there was no significant decrease in the detectable pool of in situ naphthalene in these sediments. Therefore, to better evaluate the anaerobic biodegradation of the in situ PAH pools, the concentrations of these contaminants were monitored for ca. 1 year during which the sediments were incubated under conditions that mimicked those found in situ. There was loss of all of the PAHs that were monitored (2-5 ring congeners), including high molecular weight PAHs, such as benzo[a]pyrene, that have not previously been shown to be degraded under anaerobic conditions. There was no significant change in the PAH levels in the sediments amended with molybdate to inhibit sulfate-reducing bacteria or in sediments in which all microorganisms had been killed with glutaraldehyde. In some instances, over half of the detectable pools of in situ 2-3 ring PAHs were degraded. In general, the smaller PAHs were degraded more rapidly than the larger PAHs. A distinct exception in the Boston Harbor sediment was naphthalene which was degraded very slowly at a rate comparable to the larger PAHs. In a similar in situ-like study of fuel-contaminated sediments from Liepaja Harbor, Latvia, there was no decline in PAH levels in samples that were sulfate-depleted. However, when the Latvia sediments were supplemented with sufficient sodium sulfate or gypsum to elevate pore water levels of sulfate to approximately 14-25 mM there was a 90

  16. Resting stages of Tortanus forcipatus (Crustacea, Calanoida) in sediments of Victoria Harbor, Hong Kong

    NASA Astrophysics Data System (ADS)

    Dahms, Hans-Uwe; Li, Xiangdong; Zhang, Gan; Qian, Pei-Yuan

    2006-05-01

    The distribution and abundance of viable and non-viable (so-called resting eggs) embryos of the calanoid copepod Tortanus forcipatus were determined in the laboratory by the enumeration of nauplii that emerge from sediments collected in Victoria Harbor (Hong Kong). Sediment cores sliced down to a depth of 37 cm showed the highest number of viable resting eggs near the surface layer (0-5 cm). The number of viable eggs sharply decreased with sediment depth, particularly at the inner harbor stations, although diapause eggs remained viable as deep as 25 cm. 210Pb analyses of the sediments indicated that the mean egg age was 4.9 years. The egg mortality of T. forcipatus in the sediments was 0.135 year -1, or 78.22% annual egg survival, calculated by regressing ln (egg density) from sediment age. The range of horizontal distribution of viable resting eggs was 24.25 × 10 3-58.90 × 10 3 m -2, with a mean value of 36.8 × 10 3 m -2 over all stations. The accumulation of viable resting eggs that can persist for an extended period of time provided evidence for the existence of an egg bank of T. forcipatus in the sediments of Victoria Harbor.

  17. Confirmatory sediment analyses and solid and suspended particulate phase bioassays on sediment from Oakland Inner Harbor, San Francisco, California

    SciTech Connect

    Word, J.Q.; Ward, J.A.; Apts, C.W.; Woodruff, D.L.; Barrows, M.E.; Cullinan, V.I.; Hyland, J.L.; Campbell, J.F.

    1988-12-01

    The US Army Corps of Engineers (USACE), San Francisco District, was authorized by the US Congress to deepen the navigation channels of Inner and Outer Oakland Harbor, California. During review of the environmental impact statement required for this dredging and disposal project, a panel of national experts approved the open-water disposal of dredged sediment from selected areas within the Inner Harbor, subject to results of confirmatory solid phase bioassays. The San Francisco District of the Corps requested the Battle/Marine Sciences Laboratory (MSL) to conduct these confirmatory studies. The studies provided technical data for an evaluation of the potential environmental impact of this project. Within extremely narrow time constraints, these studies provided chemical and biological information required by ocean dumping regulations to determine suitability of the Oakland Inner Harbor and turning basin sediment for ocean disposal. 23 refs., 18 figs., 45 tabs.

  18. Calculating background levels for ecological risk parameters in toxic harbor sediment

    USGS Publications Warehouse

    Leadon, C.J.; McDonnell, T.R.; Lear, J.; Barclift, D.

    2007-01-01

    Establishing background levels for biological parameters is necessary in assessing the ecological risks from harbor sediment contaminated with toxic chemicals. For chemicals in sediment, the term contaminated is defined as having concentrations above background and significant human health or ecological risk levels. For biological parameters, a site could be considered contaminated if levels of the parameter are either more or less than the background level, depending on the specific parameter. Biological parameters can include tissue chemical concentrations in ecological receptors, bioassay responses, bioaccumulation levels, and benthic community metrics. Chemical parameters can include sediment concentrations of a variety of potentially toxic chemicals. Indirectly, contaminated harbor sediment can impact shellfish, fish, birds, and marine mammals, and human populations. This paper summarizes the methods used to define background levels for chemical and biological parameters from a survey of ecological risk investigations of marine harbor sediment at California Navy bases. Background levels for regional biological indices used to quantify ecological risks for benthic communities are also described. Generally, background stations are positioned in relatively clean areas exhibiting the same physical and general chemical characteristics as nearby areas with contaminated harbor sediment. The number of background stations and the number of sample replicates per background station depend on the statistical design of the sediment ecological risk investigation, developed through the data quality objective (DQO) process. Biological data from the background stations can be compared to data from a contaminated site by using minimum or maximum background levels or comparative statistics. In Navy ecological risk assessments (ERA's), calculated background levels and appropriate ecological risk screening criteria are used to identify sampling stations and sites with contaminated

  19. Polycyclic aromatic hydrocarbons (PAHs) in starfish body and bottom sediments in Mohang Harbor (Taean), South Korea.

    PubMed

    Kim, Chang Joon; Hong, Gi Hoon; Kim, Hye Eun; Yang, Dong Beom

    2014-07-01

    The concentrations of 27 polycyclic aromatic hydrocarbons (PAHs) were determined in bottom sediments and starfish from Mohang Harbor (MH) in Taean peninsula, South Korea. In December 2007, crude oil washed ashore from the M/V Hebei Spirit and was subsequently cleaned up within a few months of the incident. The ecological risk, bioaccumulation factor (BAF), and composition of the 27 PAHs were examined. The PAH concentrations in the bottom sediment ranged from 24 to 366 μg/kg dried weight, and the ecological risk was determined as minimal (mERL-Q < 1). Total PAH concentrations in Asterina pectinifera (inside seawall) and Asterias amurensis (outside seawall) were 1,226 and 1,477 μg/kg dry weight (d.w.), respectively. The total BAFs (∑BAF) for A. amurensis was 3.8 times higher than that of A. pectinifera, and the PAH concentrations of 5-6 log K OW were highest in the two starfish species. Further, PAH fingerprint analysis (nine alkyl-substituted PAHs fraction, low molecular weight (LMW)/high molecular weight (HMW), Phe/Ant, and Flu/Pyr), and principal component analysis (PCA) based on three crude oil samples from the M/V Hebei Spirit showed no remaining influence of crude oil.

  20. EFFECT OF LAND TREATMENT ON THE MUTAGENICITY OF MILWAUKEE HARBOR SEDIMENT [POSTER PRESENTATION

    EPA Science Inventory

    Sediment from the Milwaukee harbor is known to be contaminated with PAHs and PCBs. A pilot-scale study was conducted to evaluate the potential of land treatment to detoxify these contaminants, as determined by several chemical and biological endpoints, including mutagenicity. T...

  1. EFFECT OF LAND TREATMENT ON THE MUTAGENICITY OF MILWAUKEE HARBOR SEDIMENT [POSTER PRESENTATION

    EPA Science Inventory

    Sediment from the Milwaukee harbor is known to be contaminated with PAHs and PCBs. A pilot-scale study was conducted to evaluate the potential of land treatment to detoxify these contaminants, as determined by several chemical and biological endpoints, including mutagenicity. T...

  2. Effects of harbor activities on sediment quality in a semi-arid region in Brazil.

    PubMed

    Moreira, Lucas B; Castro, Ítalo B; Hortellani, Marcos A; Sasaki, Silvio T; Taniguchi, Satie; Petti, Mônica A V; Fillmann, Gilberto; Sarkis, Jorge E S; Bícego, Márcia C; Costa-Lotufo, Leticia V; Abessa, Denis M S

    2017-01-01

    Tropical marine environments are rich in biodiversity and the presence of harbor activities in these areas can harm the coastal ecosystems. In this study, we assessed sediment quality of two harbors from a tropical region in Brazil by applying multiple lines-of-evidence approach. This approach included the integration of results on: (1) grain size, organic matter, organic carbon, nitrogen, phosphorus, trace metals, polycyclic aromatic hydrocarbons, linear alkylbenzenes, and tributyltin; (2) acute toxicity of whole sediments and chronic toxicity of liquid phases; and (3) benthic community descriptors. Our results revealed that the main contaminants detected in sediments from Mucuripe and Pecém Harbors were chromium, copper, nitrogen, zinc, and tributyltin. These toxicants arise from typical harbor activities. However, the changes in benthic composition and structure appear to depend on a combination of physical impacts, such as the deposition of fine sediments and the toxic potential of contaminants, especially in Mucuripe. Thus, apart from toxicants physical processes are important in describing risks. This information may assist in management and conservation of marine coastal areas.

  3. Effect of sediment remediation on polychlorinated biphenyl concentrations in tomatoes grown near New Bedford Harbor.

    PubMed

    Cullen, Alison C; Altshul, Larisa M; Vorhees, Donna J

    2007-10-01

    Measurements of polychlorinated biphenyl (PCB) congener concentrations and profiles from produce grown near New Bedford Harbor, Massachusetts, USA, before, during, and after remediation of PCB-contaminated sediment are presented. Samples of tomatoes collected from locations upwind and downwind relative to harbor contamination are compared with the use of measurements of 47 individual PCB congeners. The PCB concentration in the locally grown tomatoes, as expressed by the sum of congeners, is highest during the period of harbor dredging and drops to its lowest point after remediation, which included dredging and excavation. The downwind location is characterized by higher concentrations of PCBs than the upwind location in every time period. Principal component analysis is used to distinguish both the effect of remediation over time and the effect of cultivation location on the congener profiles. Evidence of the PCB congener profile representing the contaminated harbor sediments is strongest during the dredging period and in the downwind location. These results have important implications for understanding human exposure via the food chain and highlight the importance of considering exposure pathways related to atmospheric transport during remediation of contaminated sediments.

  4. PCB Content of Sediments Collected at Manistique Harbor, Michigan

    DTIC Science & Technology

    2014-06-01

    g) for potential analysis . G % water content 2e. Weigh the remaining sample that will be used for density separation. ‐ Weigh mixing  bowl  (or...whatever container the sample is in) with material. I* g container + sediment ‐ After placing sample in the centrifuge bottle (Step 3 below) weigh empty  bowl ...working with SPT. A few important items are listed here. 1. Avoid inhalation of SPT dust . Wear a dust mask or respirator when working with the powder

  5. The legacy of contaminated sediments in Boston Harbor

    USGS Publications Warehouse

    Manheim, Frank T.

    Scientists at the U.S. Geological Survey (USGS) have assembled a significant body of data that is now in a usable form. The USGS adopted an interdisciplinary approach to begin the pioneering effort at data rescue. This work involved collaboration with the Environmental Protection Agency (EPA), the U.S. Army Corps of Engineers (USACE), the Massachusetts Water Resources Authority (MWRA), Massachusetts Coastal Zone Management, and the National Oceanic and Atmospheric Administration (NOAA). More than 100,000 sediment chemistry analyses from over 1,500 samples were gleaned from 500 references, compiled, and scientifically edited by the USGS and other workers for use in studies of the distribution and fate of contaminants.

  6. Sediment toxicity in Boston Harbor: Magnitude, extent, and relationships with chemical toxicants. Technical memo

    SciTech Connect

    Long, E.R.; Sloane, G.M.; Carr, R.S.; Scott, K.J.; Thursby, G.B.

    1996-06-01

    A survey of the toxicity of sediments throughout Boston Harbor and vicinity was conducted by NOAA`s National Status and Trends (NS&T) Program. The objectives of the survey were to determine the magnitude and spatial extent of toxicity and the relationship between measures of toxicity and the concentrations of chemical toxicants in the sediments. Multiple toxicity tests were performed including: an amphipod survival test performed with whole sediments, a microbial bioluminescence test performed with organic solvent extracts of the sediments, and sea urchin fertilization and embryological development tests performed with the pore waters extracted from the sediments. Chemical analyses were performed on selected samples for trace metals, polynuclear aromatic hydrcarbons, chlorinated pesticides, PCBs, and butyltins.

  7. Option for Treatment and Disposal of Contaminated Sediments from New York/New Jersey Harbor

    DTIC Science & Technology

    1994-01-01

    contaminants of concern for this study are tetrachlorodibenzodioxins (TCDD). These chemicals, along with poly- chlorinated biphenyls (PCBs), have been detected...hydrocarbons (PAHs), chlorinated pesticides, and other haloge- nated hydrocarbons) have been detected in sediments collected in the New York/New Jersey Harbor...Dioxins Dioxins are examples of chlorinated organic compounds, which are per- sistent in the environment, can bioaccumulate, and can cause toxic effects

  8. Determining the experimental leachability of copper, lead, and zinc in a harbor sediment and modeling.

    PubMed

    Chatain, Vincent; Blanc, Denise; Borschneck, Daniel; Delolme, Cécile

    2013-01-01

    The potential leaching of pollutants present in harbor sediments has to be evaluated in order to choose the best practices for managing them. Little is known about the speciation and mobility of heavy metals in these specific solid materials. The objective of this paper is to determine and model the leachability of copper, lead, and zinc present in harbor sediments in order to obtain essential new data. The mobility of inorganic contaminants in a polluted harbor sediment collected in France was investigated as a function of physicochemical conditions. The investigation relied mainly on the use of leaching tests performed in combination with mineralogical analysis and thermodynamic modeling using PHREEQC. The modeling phase was dedicated to both confirm the hypothesis formulated to explain the experimental results and improve the determination of the main physico-chemical parameters governing mobility. The experimental results and modeling showed that the release of copper, lead, and zinc is very low with deionized water which is due to the stability of the associated solid phases (organic matter, carbonate minerals, and/or iron sulfides) at natural slightly basic conditions. However, increased mobilization is observed under pH values below 6.0 and above 10.0. This methodology helped to consistently obtain the geochemical parameters governing the mobility of the contaminants studied.

  9. Historical sources of polychlorinated biphenyls to the sediment of the New York/New Jersey Harbor.

    PubMed

    Rodenburg, Lisa A; Ralston, David K

    2017-02-01

    Using dated sediment cores, polychlorinated biphenyl (PCB) congener concentrations in the New York/New Jersey Harbor and Lower Hudson River were investigated using Positive Matrix Factorization. Of the seven factors resolved, six represent Aroclors in various stages of weathering. Factor 1 resembles Aroclor 1242 and is consistent with the Upper Hudson River PCB signal associated with the General Electric capacitor plants near Hudson Falls, NY. This factor is the dominant source of PCBs in the upper layers of the sediment core collected in the Lower Hudson River. Factor 2 (Aroclor 1248) was the dominant PCB component in the core depths corresponding with around 1970, but it has decreased more rapidly since its peak (estimated half-life of about 5 years) than factor 1 (half-life of about 14 years), suggesting that PCBs from the Upper Hudson have delayed the recovery of the Harbor from PCB contamination. The seventh factor, comprised of PCBs 206, 208, and 209, was greatest in concentration in the deepest core slices and is thought be associated with inadvertent production of PCBs during the manufacture of titanium dioxide and/or with foundry waxes containing PCBs. PCB 11, which is thought to be associated with the use of color organic pigments, was examined separately and was detected in sediment throughout the Harbor. Its maximum concentrations generally occurred at the same depth as the maximum total PCB concentrations, suggesting that PCB 11 concentrations decreased after the mid-1970s.

  10. Trace elements and their associations in sediments over the Hampton Roads Harbor and lower Chesapeake Bay area. Final report

    SciTech Connect

    Rule, J.H.

    1984-07-01

    Acid-extractable Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined on sediments from the Inner Virginia Shelf, and from shipping channels in the lower Chesapeake Bay and Hampton Roads Harbor system. Levels of Cd, Cu, Pb, and Zn exceeded average crustal abundances for most of the study sites. Cumulative frequency curves suggested that there were two major populations for all metals and perhaps a third and smaller one for Cd, Cr, and Mn. Plots of metal vs Fe indicated no anthropogenic inputs of metals for shelf and Chesapeake Bay channel sites, but suggested anthropogenic influences for all metals in several of the inshore sites. Enrichment factor calculations showed enrichment of Cd, Cu, Pb, and Zn with respect to average crustal abundances. A recommendation of this study for evaluation of environmental geochemical metals data is to utilize mean concentrations, cumulative frequency plots, and metal vs Fe and/or enrichment factor calculations when evaluating the pollution status of sediments.

  11. Nearshore disposal of fine-grained sediment in a high-energy environment: Santa Cruz Harbor case study

    USGS Publications Warehouse

    Cronin, Katherine; van Ormondt, Maarten; Storlazzi, Curt D.; Presto, Katherine; Tonnon, Pieter K.; Rosati, Julie D.; Wang, Ping; Roberts, Tiffany M.

    2011-01-01

    Current regulations in California prohibit the disposal of more than 20% fine-grained sediment in the coastal zone; this threshold is currently being investigated to determine if this environmental regulation can be improved upon. A field monitoring and numerical modeling experiment took place late 2 009 to determine the fate of fine-grained dredge disposal material from Santa Cruz Harbor, California, U.S.A. A multi-nested, hydrodynamic-sediment transport modeling approach was used to simulate the direction and dispersal of the dredge plume. Result s show that the direction and dispersal of the plume was influenced by the wave  climate, a large proportion of which moved in a easterly direction during wave events. Therefore it is vitally important to accurately simulate the tides, waves, currents, temperature and salinity when modeling the dispersal of the fine-grained dredge plume. 

  12. Potential for Polychlorinated Biphenyl Biodegradation in Sediments from Indiana Harbor and Ship Canal

    PubMed Central

    Liang, Yi; Martinez, Andres; Hornbuckle, Keri C.; Mattes, Timothy E.

    2014-01-01

    Polychlorinated biphenyls (PCBs) are carcinogenic, persistent, and bioaccumulative contaminants that pose risks to human and environmental health. In this study, we evaluated the PCB biodegradation of sediments from Indiana Harbor and Ship Canal (IHSC), a PCB-contaminated site (average PCB concentration = 12,570 ng/g d.w.). PCB congener profiles and bacterial community structure in a core sediment sample (4.57 m long) were characterized. Analysis of vertical PCB congener profile patterns in sediment and pore water strongly suggest that in situ dechlorination occurred in sediments. However, 16S rRNA genes from putative PCB-dechlorinating Chloroflexi were relatively more abundant in upper 2 m sediments, as were genes indicative of aerobic biodegradation potential (i.e. biphenyl dioxygenase (bphA)). Characterization of the bacterial community by terminal restriction fragment length polymorphism and comparison of these with sediment and pore water PCB congener profiles with the Mantel test revealed a statistical correlation (p<0.001). Sequences classified as Acinetobacter and Acidovorax were highly abundant in deep sediments. Overall, our results suggest that PCB dechlorination has already occurred, and that IHSC sediments have the potential for further aerobic and anaerobic PCB biodegradation. PMID:24764649

  13. Sediment quality in Burlington Harbor, Lake Champlain, U.S.A.

    USGS Publications Warehouse

    Lacey, E.M.; King, J.W.; Quinn, J.G.; Mecray, E.L.; Appleby, P.G.; Hunt, A.S.

    2001-01-01

    Surface samples and cores were collected in 1993 from the Burlington Harbor region of Lake Champlain. Sediment samples were analyzed for trace metals (cadmium, copper, lead, nickel, silver and zinc), simultaneously extracted metal/acid volatile sulfide (SEM-AVS), grain size, nutrients (carbon and nitrogen) and organic contaminants (polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)). The concentrations of cadmium, copper, silver and zinc from the partial sediment digestion of the surface samples correlated well with each other (r2 > 0.60) indicating that either a common process, or group of processes determined the sediment concentrations of these metals. In an analysis of the spatial distribution of the trace metals and PAHs, high surficial concentrations were present in the southern portion of the Harbor. The trace metal trend was strengthened when the concentrations were normalized by grain size. A sewage treatment plant outfall discharge was present in the southeastern portion of the Harbor at the time of this study and is the major source of trace metal and PAH contamination. Evaluation of sediment cores provides a proxy record of historical trace metal and organic inputs. The peak accumulation rate for copper, cadmium, lead, and zinc was in the late 1960s and the peak silver accumulation rate was later. The greatest accumulation of trace metals occurred in the late 1960s after discharges from the STP began. Subsequent declines in trace metal concentrations may be attributed to increased water and air regulations. The potential toxicity of trace metals and organic contaminants was predicted by comparing contaminant concentrations to benchmark concentrations and potential trace metal bioavailability was predicted with SEM-AVS results. Surface sample results indicate lead, silver, ???PAHs and ???PCBs are potentially toxic and/or bioavailable. These predictions were supported by studies of biota in the Burlington Harbor watershed. There

  14. Brownfield reuse of dredged New York Harbor sediment by cement-based solidification/stabilization

    SciTech Connect

    Loest, K.; Wilk, C.M.

    1998-12-31

    Newly effective federal regulations restrict the ocean disposal of sediments dredged from the harbors of New York and Newark. The New York Port Authority is faced with a critical situation: find land-based disposal/uses for 10`s of millions cubic yards of sediments or lose standing as a commercial port for ocean-going ships. One of the technologies now being employed to manage the sediments is portland cement-based solidification/stabilization (S/S) treatment. At least 4 million cubic yards of the sediments will undergo cement-based S/S treatment. This treatment will immobilize heavy metals, dioxin, PCBs and other organic contaminants in the sediment. The treatment changes the sediment from a environmental liability into a valuable structural fill. This structural fill is being used at two properties. The first property is an old municipal landfill in Port Newark, New Jersey. The treated sediments are being used as structural fill to cover about 20 acres of the landfill. This will allow planned redevelopment of the landfill property into a shopping mall. The second property called the Seaboard site, was the location of a coal gasification facility and later a wood preservation facility. This 160-acre property has been designated for brownfield redevelopment. Over 4 million cubic yards of treated sediments will eventually cover this site. Portland cement is the selected S/S binding reagent. Nearly 500,000 tons of cement will eventually be used to treat the sediments. Cement was selected for its ability to (a) change the peanut butter-like consistency of the sediments into a structural material and (b) to physically and chemically immobilize hazardous constituents in the sediment.

  15. Composition and distribution of polycyclic aromatic hydrocarbon contamination in surficial marine sediments from Kitimat Harbor, Canada.

    PubMed

    Simpson, C D; Mosi, A A; Cullen, W R; Reimer, K J

    1996-03-29

    Surficial marine sediments from 20 sites within the Kitimat fjord system were analyzed for polycylic aromatic hydrocarbons (PAHs). Levels of the sum of the 16 USEPA priority pollutant PAHs varied from below detection limits (ca. 1 microg x g-1) to over 10 000 microg x g-1. Sediment PAH levels were highest in the immediate vicinity of a large aluminum smelter at the head of Kitimat Arm, and declined rapidly with increasing distance from the smelter. However, even at some of the more distant sites which are geographically isolated from the smelter PAH levels were elevated. The PAH distribution in the fjord system is consistent with a combination of aeolian and fluvial transport of PAHs emitted by the aluminum smelter at the head of Kitimat Arm. The mixture of PAHs present was qualitatively similar in all samples analyzed, including those from the distant sites. All aspects of the PAH composition are consistent with combustion generated PAHs. A correlation between PAH levels and sediment organic carbon was observed; however, this was only significant for highly contaminated sites in the harbor. This probably reflects the high organic content of particulate emissions from the smelter, rather than equilibrium partitioning of PAHs to sediment organic carbon within the harbor itself.

  16. Butyltin compounds in sediments from the commercial harbor of Alexandria City, Egypt.

    PubMed

    Barakat, A O; Kim, M; Qian, Y; Wade, T L

    2001-12-01

    Tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) compounds were quantitatively determined in surface-sediment samples collected from 23 sites in the commercial harbor of Alexandria City, Egypt. Butyltin concentrations in sediments varied widely depending on the sample location, ranging from less than 0.1 to 186 ng g(-1) of Sn for MBT, less than 0.1 to 379 ng g(-1) of Sn for DBT, and 1 to 2,067 ng g(-1) of Sn for TBT Elevated TBT concentrations, ranging from 727 to 2,067 ng g(-1) of Sn were observed in harbors, marinas, and near ship-repair facilities, indicating that the butyltin-containing, antifouling paints of boats and vessels are the major source of butyltin contamination. The TBT concentration decreased rapidly away from potential source areas of boat docking and repair facilities. The high relative concentrations of TBT in the sediments indicated that degradation processes in the sediments are minor, probably due to the anoxic sedimentary conditions at the sampling sites and/or relatively fresh input of TBT to these sites.

  17. Assessment of empty microbial sheaths in sediment stabilization, Catalina Harbor, California

    NASA Astrophysics Data System (ADS)

    Thompson, K.; Waldeck, A. R.; Tookmanian, E. M.; Foster, I. S.; Petryshyn, V.; Corsetti, F. A.; Frantz, C. M.

    2016-12-01

    Tidal mudflats in Catalina Harbor, California, represent a unique opportunity to examine how microbial mats alter and stabilize their environment under dynamic conditions. Previous work has demonstrated that complex microbial communities are responsible for trapping and binding new sediment grains onto the surface of actively growing microbial mats, however little work has been done on the internal structure of the mat communities within the sediment and their resilience to disruption. We examined the microbial communities within the mats, the associated sediment system and the mechanisms used to maintain stability despite diurnal tides and physical disruption. Filaments and sheaths ( 10µm wide by >100µm long) were present on the surface of the mat and up to two centimeters below the mat surface. In contrast to the sheaths observed on the mat surface, the majority of the sheaths within the sediment were empty. Despite the fact that living cells no longer populated the sheaths, they maintained a bundled structure and appeared to stabilize sediment. To test the stability of the sediments without actively growing organisms, one set of mat and associated sediment samples were killed by autoclaving and another was autoclaved and solvent washed to remove organic material. Results demonstrated that the autoclaved mat and associated sediment maintained coherency despite the absence of living organisms, as the empty sheaths remained and supported sediment stability. In contrast, the solvent-washed samples lost coherency. This work demonstrates that microorganisms in mat communities can fundamentally alter the behaviour of sediments, and provides insight into how these communities stabilize marine, tidal mudflats even after the death of filament-producing organisms.

  18. 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.

  19. 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. © 2016 SETAC.

  20. Tsunami Induced Sedimentation in Ports; A Case Study in Haydarpasa Harbor, Marmara Sea

    NASA Astrophysics Data System (ADS)

    Yalçıner, A. C.; Kian, R.; Velioglu, D.; Zaytsev, A.

    2015-12-01

    The movement of sea bottom or ground sediment material by tsunami cause erosion, deposition and hence bathymetry and topogrphy changes. The unexpected depth decrease at some parts of the enclosed basins and harbors may result in lack of movements of vessels. In order to understand the sediment movement inside the enclosed basins, Haydarpasa port in the sea of Marama is selected as a case study to understand the motion of tsunamis inside the port and identify their effects on harbor functions. The highest populated mega city Istanbul, located at north coast of the Sea of Marmara is one of the main centers of major economic activities in the region. In the study, the spatial and temporal changes of main tsunami parameters are investigated and their adverse effects on harbor performance are identified by analyzing the critical tsunami parameters (water elevation, current speed and momentum fluxes) in the port. Furthermore, the morphological changes due to tsunami induced flows are also considered. The morphological changes due to tsunamis can be governed by bathymetry and topography, tsunami current and the characteristics of ground material. Rouse number is one of the indicators to describe the initiation of sediment motion and transport modes under the flow. Therefore the morphological changes can be monitored by monitoring the change of the Rouse number. In this study the spatial and temporal change of Rouse number and hence modes of sediment transport in Haydarpasa port during a tsunami is investigated. Finally the functional loss of the port and the necessary strategies for reduction of tsunami impact and increase of resilience are also discussed. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe)".

  1. Distribution of chlorinated organic pollutants in harbor sediments of Livorno (Italy): a multivariate approach to evaluate dredging sediments.

    PubMed

    Cicero, A M; Mecozzi, M; Morlino, R; Pellegrini, D; Veschetti, E

    2001-10-01

    Dredging is a very important procedure for harbor management. In Italy the guidelines for the offshore dumping of dredged materials are issued by the Ministry of Environment. They described a few steps of dredging activities, such as the sampling strategy, but do not deal with limits or guide-values for the chemical, physical and biological composition of the resulting sediments. The quality of dredged materials is mainly dependent on the presence of inorganic and organic pollutants. In particular, polychlorinated biphenyls (PCBs) and organo-chlorinated pesticides are seen as a high priority in marine environment by international organizations because of their persistence, toxicity and bioaccumulation capacity. In this article the presence of some PCBs and organo-chlorinated pesticides in sediment samples collected from the harbor of Livorno (Northern Tyrrhenian Sea) was investigated. The concentration of HCHs, Aldrin, Chlordanes, DDEs, DDTs, and PCBs in 12 representative sites ranged between <1 microg kg(-1) and 95, 19, 32, 35, 107, and 111 microg kg(-1), respectively. The application of univariate and multivariate statistical techniques, such as linear regression analysis and principal component analysis, to the experimental data showed a different distribution of PCBs in the two sediment layers. On the contrary, the vertical distribution of the other investigated pollutants was more homogeneous and affected by random variability. The multivariate approach was an important tool to establish more rational criteria for the management of dredged materials.

  2. Functions of effective microorganisms in bioremediation of the contaminated harbor sediments.

    PubMed

    Ekpeghere, Kalu I; Kim, Byung-Hyuk; Son, Hee-Seong; Whang, Kyung-Sook; Kim, Hee-Sik; Koh, Sung-Cheol

    2012-01-01

    The aim of this study was to apply loess balls containing effective microorganisms (EM) to the remediation of contaminated harbor sediments, and to thereby elucidate the functions of EM in remediation. Changes in physicochemical, biochemical, and microbiological parameters were measured to monitor the remediation process at a laboratory scale. Treatment with high concentrations of EM stock culture and EM loess balls (4%), and a low concentration of EM loess balls (0.1%) that contained molasses (0.05%) contributed to more rapid removal of malodor. Acetic acid, propionic acid, valeric acid, caponic acid, and lactic acid were rapidly removed in the presence of molasses (0.05% w/w) as a carbon nutrient source, indicating enhanced EM activity by amendment with molasses. Fermentation of molasses by EM showed that more acetic acid was produced compared with other organic acids, and that the majority of organic acids were eventually converted to acetate via intermediate metabolites. Sediment bioremediation tests showed there was no significant difference in eubacterial density with the control and the treatments. However, the density of a Lactobacillus sp. in sediments treated with 0.1% and 4.0% EM loess balls was significantly higher than the control, which indicated the bioaugmentation effect of EM loess balls in the polluted sediments. Treatment with EM loess balls and an appropriate amount of molasses, or other nutrients, will facilitate the remediation of polluted marine sediments by malodor removal, via EM degradation or utilization of offensive organic acids. To our knowledge, this is the first study to remediate contaminated marine (harbor) sediments using EM loess balls and to understand EM function during the bioaugmentation process, both in terms of organic acid metabolism and the dynamics of the engineered microbial community.

  3. Diagnosis of trace metal contamination in sediments: the example of Ensenada and El Sauzal, two harbors in Baja California, Mexico.

    PubMed

    Huerta-Diaz, Miguel Angel; Delgadillo-Hinojosa, Francisco; Hernández-Ayón, Martín; Segovia-Zavala, José Antonio; García-Esquivel, Zaúl; López-Zárate, Héctor; Siqueiros-Valencia, Arturo; Galindo-Bect, Salvador

    2008-09-01

    Total metal concentrations in sediments from within Ensenada and El Sauzal Harbors are generally higher than at the mouths. Grain-size analyses suggested that this enrichment could be due to the presence of fine-grained sediments in the inner part of the harbors rather than to anthropogenic perturbations. The (Me/Al)sample ratios for Pb, Co, Ni and Fe were significantly higher for Ensenada Harbor relative to El Sauzal Harbor, whereas the ratios for Cd, Mn, Zn and Cu were statistically equivalent for both harbors. Calculated enrichment factors [EFMe=(Me/Al)sample/(Me/Al)shale] indicated that the metals showing slight enrichment were those associated with anthropogenic contamination (Pb, Zn), or probably related to primary productivity in the water column (Cd, Co). The levels of most of the metals were not greatly enriched, a consideration that is of the utmost importance when contamination issues are at stake.

  4. Non-discriminating flash pyrolysis and thermochemolysis of heavily contaminated sediments from the Hamilton Harbor (Canada).

    PubMed

    Poerschmann, J; Parsi, Z; Gorecki, T

    2008-04-04

    Analytical pyrolysis of sediments contaminated with pollutants of medium to high molecular weights (up to approximately 500 Da) is very challenging when using conventional pyrolysis systems due to discrimination of high molecular weight analytes. In the framework of this contribution, non-discriminating pyrolysis and thermochemolysis using rapid heating in a Silcosteel capillary were applied to study organic pollutants in heavily contaminated sediments taken from the Hamilton Harbor. The novel pyrolysis approach, requiring very small amounts of sample, turned out to be very useful as a rapid screening method, e.g. for risk assessment studies, proving superior to commonly used solvent extraction. Main pollutants in the sediments under study included aromatic hydrocarbons, chiefly originating from coal tar and petroleum. Polycyclic aromatic hydrocarbons (PAHs) beyond six-rings, including coronene and truxene, could be detected. Sequential tetramethyl ammonium hydroxide-induced thermochemolysis performed at 500 and 750 degrees C enabled the differentiation between organic pollutants sorbed onto the sediment matrix on the one hand, and structural moieties of the condensed polymeric humic sediment matrix along with bound residues on the other hand. Thermochemolysis at 500 degrees C removed sorbates quantitatively, leaving only bare polymeric humic matrix. Significant PAH source indicators provided evidence that the lipidic fraction sorbed onto the sediments originated from PAHs formed chiefly in coal combustion processes. The polymeric humic organic matter network of the less polluted sediment was mainly of petrogenic origin, whereas black carbon, kerogen, etc. contributed to the organic carbon of the heavily polluted sediment. Thermochemolysis at 500 degrees C was also used to study fatty acid profiles of the sediments. The fatty acid methyl ester patterns obtained for the two sites under study differed significantly, with strong indications that microbial attenuation

  5. Determination of Polycyclic Aromatic Hydrocarbons in Industrial Harbor Sediments by GC-MS

    PubMed Central

    Dong, Cheng-Di; Chen, Chih-Feng; Chen, Chiu-Wen

    2012-01-01

    Analysis of the 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority pollutant list was carried out in sediment samples of an industrial port in the southern Kaohsiung Harbor of Taiwan which is supposed to be extensively polluted by industrial wastewater discharges. The determination and quantification of PAHs in sediment samples were performed using gas chromatography coupled to mass spectrometry (GC-MS) with the aid of deuterated PAH internal standards and surrogate standards. The total concentrations of the 16 PAHs varied from 4,425 to 51,261 ng/g dw, with a mean concentration of 13,196 ng/g dw. The PAHs concentration is relatively high in the river mouth region, and gradually diminishes toward the harbor region. Diagnostic ratios showed that the possible source of PAHs in the industrial port area could be coal combustion. As compared with the US Sediment Quality Guidelines (SQGs), the various observed levels of PAHs exceeded the effects range median (ERM), and could thus cause acute biological damages. The results can be used for regular monitoring, and future pollution prevention and management should target the various industries in this region for reducing pollution. PMID:22829797

  6. Speciation of butyltin derivatives in surface sediments of three southern Brazilian harbors.

    PubMed

    de Oliveira, Cristiane Rossi; dos Santos, DayanaMoscardi; Madureira, Luiz Augusto dos Santos; de Marchi, Mary Rosa Rodrigues

    2010-09-15

    For the first time, organotin compounds were determined in surface sediment samples collected from São Francisco do Sul, Itajaí-Navegantes and Imbituba Harbors, located in Santa Catarina State, Brazil. Butyltins (BTs) were determined by gas chromatography with a pulsed flame photometric detector (GC-PFPD) after being modified using the Grignard derivatization method. The concentrations of BTs derivatives ranged from n.d. to 1136.6 ng (Sn) g(-1) of dry weight (dw) sediment for tributyltin (TBT), n.d. to 394.4 ng (Sn)g(-1) dw for dibutyltin (DBT) and n.d. to 312.2 ng (Sn) g(-1) dw for monobutyltin (MBT). The highest concentration of total BTs was found at the Itajaí-Açu River dockyard, indicating intense inputs of antifouling paints to the environment. The relative difference in the BTs levels is a particular characteristic of sediments from harbors and may be related to the shipyards and the boat traffic which still use TBT-based antifouling paints. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Sediment scour and deposition within harbors in California (USA), caused by the March 11, 2011 Tohoku-oki tsunami

    NASA Astrophysics Data System (ADS)

    Wilson, Rick; Davenport, Clif; Jaffe, Bruce

    2012-12-01

    Tsunamis have caused significant damage to boats and docks within harbors and ports along the California coast. Sediment scour and deposition within harbors by tsunamis, though not extensively studied, have produced long-term impacts to the recovery and resiliency of affected maritime communities. The March 11, 2011 Tohoku-oki teletsunami generated strong tsunami currents (up to 7 m/s, or 14 kn) within Crescent City and Santa Cruz harbors that triggered sedimentation problems, regulatory issues with sediment disposal, and months of delays in the reconstruction process. Evaluation of video, pre- and post-tsunami bathymetric surveys, and harbor sediment analysis data helped develop a better understanding of tsunami flow regime and sediment transport within these harbors. In Crescent City, the scour effects of large tsunami surges were amplified by the narrow entrance to the Small-Boat Basin, increasing the sediment supply and trapping this material within the basin, causing shoaling that made the harbor unusable and creating long-term disposal issues. Within the entire harbor, at least 289,400 m3 of sediment was scoured in an area of 0.67 km2. A minimum fill volume of 154,600 m3 was calculated with the sediment covering 55% of that portion of the harbor included in the bathymetric surveys. In Santa Cruz, the long, constricting layout and shallow nature of the harbor increased current velocities and scour in confined areas, and exacerbated sedimentation in between and beneath docks. At the harbor entrance, estimated scour volumes range from 2550 to 14,800 m3, and fill estimates range from 120 to 8750 m3, depending upon the surveys used to characterize post-tsunami conditions, while the area of deposition ranges from 6 to 64% of the survey overlap areas. About 83 m3 of sediment was scoured in Santa Cruz North Harbor, while a minimum of 75 m3 was deposited across 50% of that portion of the harbor common to pre- and post-tsunami surveys. Fill estimates are considered

  8. Temporal Movement of the Geochemical "Fingerprint" of the World Trade Center Terrorist Attack in New York Harbor Sediments

    NASA Astrophysics Data System (ADS)

    Smith, J. P.; Oktay, S. D.; Brabander, D. J.; Olsen, C. R.; Kada, J.

    2002-12-01

    The September 11, 2001 terrorist attack on the World Trade Center (WTC) in New York City introduced large amounts of ash and debris over a wide area including New York Harbor (NYH) and the Lower Hudson River Estuary. Previous results, based on data from ash/debris collected after the event and from sediment cores taken on October 12, 2001 in inactive harbor slips along the lower west side of Manhattan, have identified a textural and elemental "fingerprint" for the ash/debris, and have documented a stratigraphic horizon for the event in New York Harbor sediments. On July 24 and July 25, 2002, almost eleven months after the attack, the same sample sites were revisited and new sediment cores collected. Sediment samples were analyzed using radionuclide tracers (Be-7, Cs-137, I-131) and textural and elemental (major- and trace-element) characterizations were made in order to: 1) document the temporal progression of the fingerprint as a distinct horizon preserved in the sediments of New York Harbor; and 2) investigate how short-to-medium term sediment dynamics (supply, deposition, re-suspension, and net accumulation) may affect the preservation of a sedimentological record associated with the event. These results will be used to evaluate whether the WTC geochemical fingerprint may serve as a tool to help assess the impact of the attack and as a tracer for short to medium term sediment dynamics in the Lower Hudson River Estuary.

  9. Polluted harbor sediment and the annual reproductive cycle of the female flounder, Platichthys fiesus (L.)

    SciTech Connect

    Janssen, P.A.H.; Lambert, J.G.D.; Goos, H.J.T.; Wezel, A.P. van; Opperhuizen, A.

    1995-12-31

    Compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs),and pesticides are metabolized by enzyme systems, which are also involved in steroid metabolism. Disturbances of reproduction may therefore occur through the interference of these compounds with the endocrine system. Several aspects of reproduction were studied in the flounder, Platichthys fiesus (L.), an euryhaline flatfish which inhabits coastal waters and is therefore a suitable biomonitor for the effects of chemical pollutants. Fish were kept during three years in mesocosm systems of which the first provided a control, while the second one contained polluted sediment, derived from the Rotterdam harbor. In November, all ovaries from both mesocosms contained vitellogenic oocytes. In May, all the control fish were previtellogenic, while the ovaries of fish from the polluted mesocosm contained, besides previtellogenic oocytes, a large number of vitellogenic oocytes, indicating that an estrogenic induction had occurred. The in vitro tissue incubations with androstenedione as precursor revealed that the ovarian capacity to synthesize testosterone (T), estrone (E{sub 2}) and 17{beta}-estradiol (E{sub 2}) didn`t differ between both mesocosms. In May, however, the levels of T and E{sub 2} as well as the level of the yolk-precursor vitellogenin were significantly higher in the polluted mesocosm. The conclusion from this study was that polluted harbor sediment contains compounds that effect normal reproductive development, i.e. the induction of premature vitellogenesis.

  10. PAH mineralization and bacterial organotolerance in surface sediments of the Charleston Harbor estuary.

    PubMed

    Montgomery, Michael T; Boyd, Thomas J; Osburn, Christopher L; Smith, David C

    2010-04-01

    Semi-volatile organic compounds (SVOCs) in estuarine waters can adversely affect biota but watershed sources can be difficult to identify because these compounds are transient. Natural bacterial assemblages may respond to chronic, episodic exposure to SVOCs through selection of more organotolerant bacterial communities. We measured bacterial production, organotolerance and polycyclic aromatic hydrocarbon (PAH) mineralization in Charleston Harbor and compared surface sediment from stations near a known, permitted SVOC outfall (pulp mill effluent) to that from more pristine stations. Naphthalene additions inhibited an average of 77% of bacterial metabolism in sediments from the more pristine site (Wando River). Production in sediments nearest the outfall was only inhibited an average of 9% and in some cases, was actually stimulated. In general, the stations with the highest rates of bacterial production also were among those with the highest rates of PAH mineralization. This suggests that the capacity to mineralize PAH carbon is a common feature amongst the bacterial assemblage in these estuarine sediments and could account for an average of 5.6% of bacterial carbon demand (in terms of production) in the summer, 3.3% in the spring (April) and only 1.2% in winter (December).

  11. Sources and areal distribution of trace metals in recent sediments of Middle Loch, Pearl Harbor (Hawaii)

    SciTech Connect

    Ashwood, T.L.; Olsen, C.R.; Larsen, I.L.

    1989-05-01

    The primary objective of this project was to determine whether current operations of the Naval Inactive Ships Maintenance Facility contribute significant trace metal contamination to Middle Loch of Pearl Harbor. Secondary objectives were (1) to identify and quantify all major sources of trace metal contamination in Middle Loch and (2) to determine if trace metal concentrations in Middle Loch have declined following termination of direct discharges from the Pearl City Sewage Treatment Plant. Sediment samples from ten locations within Middle Loch and from two locations in each of the two major streams entering the loch were analyzed for radioisotopes and metals. Major elements (aluminum and calcium) as well as organic and inorganic carbon were used to help characterize sediment composition and source. High aluminum-to-calcium ratios and high organic carbon concentrations are associated with terrigenous material carried into Middle Loch by the streams. The presence of the natural, short-lived (53-d half-life) radioisotope /sup 7/Be was used to identify sites where the sedimentary material was recently deposited (i.e., within the past 3 months) and to identify patterns of recent sediment accumulation. Beryllium-7 was detected at eight of the ten sample sites within Middle Loch and in all stream samples. High /sup 7/Be inventories beneath the ships and at the mouths of the streams suggest that these are areas of rapid sediment accumulation, or sediment focusing. The concentrations of /sup 7/Be closely match the expected input based on rain-bucket data. This suggests that Middle Loch effectively traps all the /sup 7/Be through adsorption onto suspended matter and deposition to the sediments. 14 refs., 10 figs., 8 tabs.

  12. Hexabromocyclododecanes in surface sediments and a sediment core from Rivers and Harbor in the northern Chinese city of Tianjin.

    PubMed

    Zhang, Yanwei; Ruan, Yuefei; Sun, Hongwen; Zhao, Lijie; Gan, Zhiwei

    2013-02-01

    In the present study, hexabromocyclododecanes (HBCDs) were investigated in the sediment from Haihe River (HR), Dagu Dainage Canal (DDC) and Tianjin Harbor (TH) at Bohai Bay using a total of 51 samples of surface sediments and a sediment core collected from May to September in 2010, and its diastereomer- and enantiomer-specific profiles were analyzed. The concentration of total HBCDs were generally high, with mean value and ranges of 31.0 and 1.35-634 ng g(-1)dw, respectively. The contamination followed the order of TH>DDC>HR. Higher levels (up to 634 ng g(-1)dw) occurred in the lower reach of HR and DDC located in an industrial area of Tianjin. This is the first time to report so high concentration of HBCDs in sediment in Southeast Asia. The γ-diastereomer dominated in most samples (44 out of 51), and this is in agreement with the diastereomer distribution pattern in industrial products, while α-HBCD was the dominant diastereomer in the other seven samples. However, only few samples exhibited γ-diastereomer ratio similar to that (75-89%) in technical products, indicating the inter-transformation and variable degradation of the different isomers. The high ratio of γ-diastereomer could be used as an indicator for fresh contamination input. Enantiomeric factors (EFs) of HBCD isomers in most of the samples were statistically different from technical products (p<0.05), showing a trend of more easily enrichment of the (-)-HBCD-enantiomer compared to the (+)-HBCD-enantiomer. The δ- and ε-diastereomers were frequently detected but at low level. The HBCDs in the sediment core showed several peaks, and the greatest value occurred in 2005, when a plastic manufacture plant using HBCD was set up nearby.

  13. Assessment of sediment contamination, acute toxicity, and population viability of the estuarine amphipod Leptocheirus plumulosus in Baltimore Harbor, Maryland, USA

    SciTech Connect

    McGee, B.L.; Fisher, D.J.; Yonkos, L.T.; Ziegler, G.P.; Turley, S.

    1999-10-01

    In Chesapeake Bay, Maryland, USA, some of the most contaminated sediments are found in the highly industrialized Baltimore Harbor-Patapsco River area. As part of a comprehensive assessment of sediment quality in this system, sediment toxicity was assessed in 10-d acute tests with the estuarine amphipod Leptocheirus plumulosus. Mean amphipod survival was significantly reduced in 7 of the 25 samples tested despite the occurrence of minor experimental artifacts. The most toxic sediments were collected from Bear Creek; other areas exhibiting toxicity included the Inner Harbor and Colgate Creek. Marginal toxicity was observed in samples from Curtis Creek, Lazeretto Point, and Back River. Negative relationships were detected between survival and concentrations of select sediment-associated contaminants, whereas a very strong positive association existed between survival in laboratory exposures and density of L. plumulosus at the test sites. A weight of evidence approach, including correlation analyses, a model of polycyclic aromatic hydrocarbon bioavailability, and comparisons to benchmark sediment levels, was used to tentatively identify classes of contaminants that contributed to the observed toxicity. Analysis of results suggested that toxicity at stations in Bear Creek and Colgate Creek may have been driven by sediment-associated metals, whereas toxicity at stations in the Inner Harbor was likely due to both metal and organic contaminants. The observed relationships among toxicity test results, concentrations of sediment-associated contaminants, and abundance of L. plumulosus at the test sites suggests that acute toxicity tests with this species are indicative of adverse biological effects in the field.

  14. NMR-based metabolomics for the environmental assessment of Kaohsiung Harbor sediments exemplified by a marine amphipod (Hyalella azteca).

    PubMed

    Chiu, K H; Dong, C D; Chen, C F; Tsai, M L; Ju, Y R; Chen, T M; Chen, C W

    2017-03-03

    Inflow of wastewater from upstream causes a large flux of pollutants to enter Kaohsiung Harbor in Taiwan daily. To reveal the ecological risk posed by Kaohsiung Harbor sediments, an ecological metabolomic approach was employed to investigate environmental factors pertinent to the physiological regulation of the marine amphipod Hyalella azteca. The amphipods were exposed to sediments collected from different stream inlets of the Love River (LR), Canon River (CR), Jen-Gen River (JR), and Salt River (SR). Harbor entrance 1 (E1) was selected as a reference site. After 10-day exposure, metabolomic analysis of the Hyalella azteca revealed differences between two groups: {E1, LR, CR} and {JR, SR}. The metabolic pathways identified in the two groups of amphipods were significantly different. The results demonstrated that NMR-based metabolomics can be effectively used to characterize metabolic response related to sediment from polluted areas.

  15. Toxicological evaluation of sediment samples from Burns Harbor, Porter County, Indiana

    SciTech Connect

    Ward, J.A.; Pinza, M.R.; Barrows, M.E.; Karls, R.K.; Word, J.Q.

    1994-05-01

    The US Army Corps of Engineers (USACE) Chicago District is authorized to maintain the water depths in Burns Harbor at navigable levels. In order to maintain these levels, sediments must be dredged and disposed of at approved disposal sites. To make a 404 (b) 1 open-water disposal evaluation, the dredged sediment may be evaluated through a series of toxicological tests to assess its potential for causing an adverse environmental effect. Battelle/Marine Sciences Laboratory (MSL) was contracted by USACE to perform these freshwater toxicity tests. The tests were designed to simulate conditions that organisms living within an aquatic dredged material disposal site might experience during disposal operations, and included both bedded-sediment (solid-phase) and suspended-sediment (elutriate) tests. Test samples were collected by USACE personnel and composited into three test treatments representing potential dredging areas (Management Units {number_sign}1, {number_sign}2, and {number_sign}3). Four toxicological tests were conducted in support of this program. The solid-phase tests included the amphipod, Hyalella azteca, and the midge, Chironomus tentans. The elutriate tests included the fathead minnow, Pimephales promelas, and the daphnid, Daphnia magna. Testing was conducted following standard procedures provided by USACE which are consistent with ASTM protocols and the Evaluation of Dredged Material Proposed for Discharge in Inland and Near Coastal Waters -- Testing Manual (Draft) Inland Testing Manual (EPA/USACE 1993), known as the ``Draft Inland Testing Manual.`` The suitability of sediment representing the management units for open-water disposal was evaluated following the guidelines contained in the Draft Inland Testing Manual.

  16. Contaminant levels and toxicity of sediments and water of Baltimore Harbor and Back River, Maryland

    SciTech Connect

    Logan, D.T.; Jacobs, F.; Mehrotra, N.

    1995-12-31

    The Patapsco and Back River Watershed drains the Baltimore metropolitan area, Maryland`s most heavily industrialized and urbanized region. Due to the intensive development and industrialization of the Baltimore metropolitan area over the past 250 years, high levels of contaminants have been discharged into Baltimore Harbor on the Patapsco River and into the Back River. Pollutants historically discharged include heavy metals, petroleum hydrocarbons, pesticides, cyanide, sewage, other organic chemicals, and nutrients. Sources have included industrial and municipal discharges, sewerage overflows, urban runoff, and leaks and spills from vessels and on-land facilities. The Maryland Department of the Environment undertook this study of ambient conditions as part of a developing strategy to assess and improve conditions in the Chesapeake Bay and its tributaries. Past studies were compiled, evaluated, and synthesized to identify the areas of degraded conditions and contaminants of possible concern. Sediment contaminant levels were assessed using historical sediment chemistry data, Effects Range Low and Median concentrations (ER-L and ER-M) as toxicological benchmarks, and a sum of toxicity units approach for multiple contaminants. Data on toxicity testing and biological monitoring was compared to sediment and water quality data. Fish tissue data were used to examine bioaccumulated chemicals. A computerized Geographical Information System (GIS) was used to manipulate and display complex geographical data. The final identification of areas and chemicals of potential concern relied on a syntheses of these results as well as information on present and past contaminant loadings.

  17. Laboratory tests for the phytoextraction of heavy metals from polluted harbor sediments using aquatic plants.

    PubMed

    Mânzatu, Carmen; Nagy, Boldizsár; Ceccarini, Alessio; Iannelli, Renato; Giannarelli, Stefania; Majdik, Cornelia

    2015-12-30

    The aim of this study was to investigate the concentrations and pollution levels of heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons in marine sediments from the Leghorn Harbor (Italy) on the Mediterranean Sea. The phytoextraction capacity of three aquatic plants Salvinia natans, Vallisneria spiralis, and Cabomba aquatica was also tested in the removal of lead and copper, present in high concentration in these sediments. The average detectable concentrations of metals accumulated by the plants in the studied area were as follows: >3.328 ± 0.032 mg/kg dry weight (DW) of Pb and 2.641 ± 0.014 mg/kg DW of Cu for S. natans, >3.107 ± 0.034 g/kg DW for V. spiralis, and >2.400 ± 0.029 mg/kg DW for C. aquatica. The occurrence of pesticides was also analyzed in the sediment sample by gas chromatography coupled with mass spectrometry (GC/MS). Due to its metal and organic compound accumulation patterns, S. natans is a potential candidate in phytoextraction strategies.

  18. Preparation of low water-sorption lightweight aggregates from harbor sediment added with waste glass.

    PubMed

    Wei, Yu-Ling; Lin, Chang-Yuan; Ko, Kuan-Wei; Wang, H Paul

    2011-01-01

    A harbor sediment is successfully recycled at 1150 °C as low water-absorption lightweight aggregate via addition of waste glass powder. Sodium content in the waste glass is responsible for the formation of low-viscosity viscous phases during firing process to encapsulate the gases generated for bloating pellet samples. Water sorption capacity of the lightweight products can be considerably reduced from 5.6% to 1.5% with the addition of waste glass powder. Low water-absorption property of lightweight products is beneficial for preparing lightweight concrete because the water required for curing the cement would not be seized by lightweight aggregate filler, thus preventing the failure of long-term concrete strength.

  19. Carcinogenicity of Black Rock Harbor sediment to the eastern oyster and trophic transfer of Black Rock Harbor carcinogens from the blue mussel to the winter flounder

    SciTech Connect

    Gardner, G.R.; Yevich, P.P.; Malcolm, A.R. ); Harshbarger, J.C. )

    1991-01-01

    The eastern oyster (Crassostrea virginica) developed neoplastic disorders when experimentally exposed both in the laboratory and field to chemically contaminated sediment from Black Rock Harbor (BRH), Bridgeport, Connecticut. Neoplasia was observed in oysters after 30 or 60 days of continuous exposure in a laboratory flow-through system to a 20 mg/L suspension of BRH sediment plus postexposure periods of 3, 30, or 60 days. Composite tumor incidence was 13.6% for both exposures. Tumor occurrence was highest in the renal excretory epithelium, followed in order by gill, gonad, gastrointestinal, heart, and embryonic neural tissue. Regression of experimental neoplasia was not observed when the stimulus was discontinued. In field experiments, gill neoplasms developed in oysters, deployed in cages for 30 days at BRH and 36 days at a BRH dredge material disposal area in Central Long Island Sound, and kidney and gastrointestinal neoplasms developed in caged oysters deployed 40 days in Quincy Bay, Boston Harbor. Oysters exposed to BRH sediment in the laboratory and in the field accumulated high concentrations of polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), and chlorinated pesticides. Chemical analyses demonstrated high concentrations of PCBs, PAHs, chlorinated pesticides, and heavy metals in BRH sediment. Known genotoxic carcinogens, cocarcinogens, and tumor promoters were present as contaminants. The uptake of parent PAH and PCBs from BRH sediment observed in oysters also occurs in blue mussels (Mytilus edulis). Winter flounder fed BRH-contaminated blue mussels contained xenobiotic chemicals analyzed in mussels. The flounder developed renal and pancreatic neoplasms and hepatotoxic neoplastic precursor lesions, demonstrating trophic transfer of sediment-bound carcinogens up the food chain.

  20. Carcinogenicity of Black Rock Harbor sediment to the eastern oyster and trophic transfer of Black Rock Harbor carcinogens from the blue mussel to the winter flounder.

    PubMed Central

    Gardner, G R; Yevich, P P; Harshbarger, J C; Malcolm, A R

    1991-01-01

    The eastern oyster (Crassostrea virginica) developed neoplastic disorders when experimentally exposed both in the laboratory and field to chemically contaminated sediment from Black Rock Harbor (BRH), Bridgeport, Connecticut. Neoplasia was observed in oysters after 30 and 60 days of continuous exposure in a laboratory flow-through system to a 20 mg/L suspension of BRH sediment plus postexposure periods of 0, 30, or 60 days. Composite tumor incidence was 13.6% (49 neoplasms in 40, n = 295) for both exposures. Tumor occurrence was highest in the renal excretory epithelium, followed in order by gill, gonad, gastrointestinal, heart, and embryonic neural tissue. Regression of experimental neoplasia was not observed when the stimulus was discontinued. In field experiments, gill neoplasms developed in oysters deployed in cages for 30 days at BRH and 36 days at a BRH dredge material disposal area in Central Long Island Sound, and kidney and gastrointestinal neoplasms developed in caged oysters deployed 40 days in Quincy Bay, Boston Harbor. Oysters exposed to BRH sediment in the laboratory and in the field accumulated high concentrations of polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), and chlorinated pesticides. Chemical analyses demonstrated high concentrations of PCBs, PAHs, chlorinated pesticides, and heavy metals in BRH sediment. Known genotoxic carcinogens, co-carcinogens, and tumor promoters were present as contaminants. The uptake of parent PAH and PCBs from BRH sediment observed in oysters also occurs in blue mussels (Mytilus edulis). Winter flounder fed BRH-contaminated blue mussels contained xenobiotic chemicals analyzed in mussels. The flounder developed renal and pancreatic neoplasms and hepatotoxic neoplastic precursor lesions, demonstrating trophic transfer of sediment-bound carcinogens up the food chain. Images FIGURE 2. FIGURE 3. FIGURE 4. FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8. FIGURE 9. FIGURE 10. PMID:2050083

  1. 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.

  2. Geochemical Fingerprinting of the World Trade Center Attack in New York Harbor Sediments

    NASA Astrophysics Data System (ADS)

    Brabander, D. J.; Oktay, S.; Smith, J.; Kada, J.; Bullen, T.; Olsen, C.

    2002-12-01

    By comparing the textural, chemical, and isotopic composition of World Trade Center (WTC) ash samples (collected near Ground Zero one week after the terrorist attack) with sediment samples from cores taken on October 12, 2001 in known deposition areas in New York Harbor (NYH), we characterized a unique suite of geochemical-textural tracers that allow us to both identify and quantify the input of WTC derived material to adjacent areas in the Hudson River estuary. Scanning electron microscopy coupled with energy dispersive spectroscopy revealed two chemically distinct (Si-rich and Ca-rich) rod-like features (40-200 æm in length) in both ash and sediment samples. The Si-rich rods are consistent with a fiberglass parent material while the Ca-rich rods originate from gypsum. An 87Sr/86Sr ratio for the ash material of 0.7088 (n=2) coupled with Ca/Sr (wt. ratio) ranging from 260-300 suggest that the ash material analyzed is approximately 70% gypsum. As a function of depth within the sediment core, correlations exist between the measured activities of 7Be (a naturally occurring short-lived radionuclide), elemental weight-percent ratios of Ca/Sr, and the isotopic ratios of 87Sr/86Sr ratios. . These combined isotopic approaches allow us to constrain the timing (via 7Be), and the composition and amount (via 87Sr/86Sr and Ca/Sr) of WTC material input into the NYH sediments. These down-core isotope-ratio profiles can be described by a mixing line between background NYH 87Sr/86Sr ratios (>0.724) and the WTC derived ash material. The geochemical-textural tracers associated with the WTC terrorist attack may provide a potential tool for assessing the fate and transport of WTC material in the Lower Hudson River and aid in assessing the environmental and human health impacts of the WTC catastrophe.

  3. PAH Biodegradation, Turnover, and Ambient Concentration in Surface Sediments of Coaster’s Harbor and Narragansett Bay

    DTIC Science & Technology

    2007-11-02

    TELEPHONE NUMBER (include area code) b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT January 21, 2003 PAH Biodegradation ...sediments at the Coaster’s Harbor site would be difficult given the large amount of benthos covered by rock or confluent with eelgrass. PAH biodegradation ...1 PAH Biodegradation

  4. Enhanced-electrokinetic extraction of heavy metals from dredged harbor sediment.

    PubMed

    Yoo, Jong-Chan; Yang, Jung-Seok; Jeon, Eun-Ki; Baek, Kitae

    2015-07-01

    In this study, the feasibility of an ex situ electrokinetic (EK) process combined with pre-oxidation using hydrogen peroxide (H2O2) and pre-washing using ethylenediaminetetraacetic acid (EDTA) was investigated in enhancing the extraction of Cu, Pb, and Zn from actual dredged harbor sediment. H2O2 pre-oxidation led to a change in the fractionation of Cu bound to organic matter and the sulfide fraction in the Fe-Mn oxides to the exchangeable fraction, but was not effective at removing metals. In contrast, EDTA pre-washing changed the Fe-Mn oxide-bound fractions of Cu and Pb into easily extractable fractions; 20.1, 27.5, and 32.8% of Cu, Pb, and Zn were removed, respectively. During EK treatment, metals were transported toward the anode by electromigration of negatively charged complexes such as metal-EDTA and metal-citrate. However, EK treatment did not significantly enhance the removal of metals because metals accumulated near the anodic region with an increase in the exchangeable fraction due to the short EK operating duration and low voltage gradient. Therefore, it is necessary to extend the EK operating duration and/or increase the voltage gradient for effective transportation and removal of metals from sediment.

  5. Microscale location, characterization, and association of polycyclic aromatic hydrocarbons on harbor sediment particles

    SciTech Connect

    Ghosh, U.; Gillette, J.S.; Luthy, R.G.; Zare, R.N.

    2000-05-01

    Complementary mass spectrometric and spectroscopic techniques were employed to provide direct information at the microscale on the sequestration of polycyclic aromatic hydrocarbon (PAH) contaminants in Milwaukee Harbor sediment particles. Microprobe two-step laser desorption/laser ionization mass spectrometry was used for PAH measurements, infrared microspectroscopy was used for organic carbon measurement, and scanning electron microscopy with wavelength dispersive X-ray spectroscopy was used for elemental microanalysis. PAH concentrations on coal- and wood-derived particles were found to be several orders of magnitude higher than on silica particles. A cryomicrotome sectioning procedure was employed for particle cross-sectional investigations, and it was found that most PAHs are concentrated on external surface regions indicating near surface sorption mechanisms. The coal/wood-derived particles constitute only 5% of the sediment by weight but contain 62% of the total PAHs. The remaining 38% are mainly in a clay and silt fraction. PAH desorption kinetic studies on these separated fractions revealed a relatively low availability of PAHs from the coal/wood fractions and a high availability from the clay/silt fraction. Additionally, these PAH-bearing coal/wood-derived particles may be removed by density separation from heavier clay, silt, and sand.

  6. Coastal Marsh Sediments from Bodega Harbor: Archives of Environmental Changes at the Terrestrial-Marine Interface

    NASA Astrophysics Data System (ADS)

    Rademacher, L. K.; Rong, Y.; Hill, T. M.; Hiromoto, C.; Fisher, A.

    2010-12-01

    Coastal marsh sediments provide an important archive of environmental changes at the terrestrial-marine interface. Over the last century, humans have significantly altered the coastal environment near Bodega Bay, California, through changes in hydrology, sediment sources, and the dominant ecosystem. Previous investigations of recent coastal marsh sediments (< 50 years) suggest that physical barriers, such as roads, which limit the connection between Bodega Bay and the marshes, alters biogeochemical cycling (including carbon storage) in the coastal environment. The present study extends the record of changes in biogeochemical cycling in the coastal marshes back more than 100 years (approximately 90 cm) through the use of grain size analysis, C and N isotopes, and age dating. Sediments were analyzed for grain size distribution, the amount of carbon and nitrogen, and the stable isotopes of carbon and nitrogen in 1 cm intervals throughout the core. In addition, a subset of eight samples was analyzed for sediment age using a combination of Pb-210 and Cs-137 techniques. Sediments from >40 cm and <55 cm depth have a higher percentage of fine-grained sediment (>2%). In addition, these sediments also contain higher levels of total organic carbon and nitrogen, higher C:N ratios, we well as heavier carbon and nitrogen isotopic signatures. The sediments likely correspond to a pre-1900 depositional environment based on Pb-210 dates, when development in the region was increasing. These results suggest a stronger influence of the marine environment during that time. Interestingly, smaller transitions in sediment properties toward what appears to reflect a more marine environment also occur near the top of the core (<10 cm depth) and near the bottom of the core (>75 cm depth). Although these transitions are less pronounced, the significant shift in sediment properties suggests a less stable environment with greater communication between the terrestrial and marine environments

  7. Spatial Distributions of Iodine-131 and the Geochemical "Fingerprint" from the World Trade Center Terrorist Attack in New York Harbor Sediments

    NASA Astrophysics Data System (ADS)

    Oktay, S. D.; Smith, J. P.; Brabander, D. J.; Kada, J.; Olsen, C. R.

    2002-12-01

    The September 11, 2001 terrorist attack on the World Trade Center (WTC) in New York City introduced large amounts of ash and debris over an extensive area including New York Harbor (NYH) and the Lower Hudson Estuary. Previous results have identified a textural and elemental "fingerprint" for this ash/debris that can be seen as a quantifiable event horizon in NYH surface sediments. In addition, the short-lived radioisotope, I-131 (half-life, 8.04 days), was unexpectedly identified in the surface sediments, which corroborated that this sediment was recently deposited and anthropogenically influenced. On July 24-25, 2002, additional sediment cores were collected in the sites occupied in 2001 and in various locations throughout NYH (on both the Manhattan and New Jersey sides of the Hudson river) in order to determine the spatial extent of both the WTC "fingerprint" and the I-131 signal. Gamma spectrometric measurements of I-131 in surface sediments were used to determine its spatial distribution in NYH sediments and its potential use as an indicator of rapid sedimentary processes (days to weeks) initiated by urban input. Potential sources for the I-131 were evaluated, with initial evidence pointing to traces of human waste discharge related to medical treatments as the most likely source. The short-lived radionuclide, Be-7 (half-life, 53.12 days), and textural and elemental characterizations originally identified in the earlier research were examined in order to document the spatial distribution of the geochemical WTC "fingerprint" and investigate how short-to-medium term sediment dynamics (supply, deposition, re-suspension, and net accumulation) in New York Harbor may affect the spatial distribution and preservation of a sedimentological record associated with this event. This research should help delineate the geographical extent of the debris created from the WTC catastrophe and may predict where urban inputs of material such as I-131 can accumulate in NYH.

  8. Specific 16S rDNA sequences associated with naphthalene degradation under sulfate-reducing conditions in harbor sediments.

    PubMed

    Hayes, L A; Lovley, Derek R

    2002-01-01

    Previous studies have demonstrated that naphthalene and other polycyclic aromatic hydrocarbons (PAHs) can be anaerobically oxidized with the reduction of sulfate in PAH-contaminated marine harbor sediments, including those in San Diego Bay. In order to learn more about the microorganisms that might be involved in anaerobic naphthalene degradation, the microorganisms associated with naphthalene degradation in San Diego Bay sediments were evaluated. A dilution-to-extinction enrichment culture strategy, designed to recover the most numerous culturable naphthalene-degrading sulfate reducers, resulted in the enrichment of microorganisms with 16S rDNA sequences in the d-Proteobacteria, which were closely related to a previously described pure culture of a naphthalene-degrading sulfate reducer, NaphS2, isolated from sediments in Germany. A more traditional enrichment culture approach, expected to enrich for the fastest-growing naphthalene-degrading sulfate reducers, yielded 16S rDNA sequences closely related to those found in the dilution-to-extinction enrichments and NaphS2. Analysis of 16S rDNA sequences in sediments from two sites in San Diego Bay that had been adapted for rapid naphthalene degradation by continual amendment with low levels of naphthalene suggested that the microbial community composition in the amended sediments differed from that present in the unamended sediments from the same sites. Most significantly, 6-8% of the sequences recovered from 100 clones of each of the naphthalene-amended sediments were closely related to the 16S rDNA sequences in the enrichment cultures as well as the sequence of the pure culture, NaphS2. No sequences in this NaphS2 phylotype were recovered from the sediments that were not continually exposed to naphthalene. A PCR primer, which was designed based on these phylotype sequences, was used to amplify additional 16S rDNA sequences belonging to the NaphS2 phylotype from PAH-degrading sediments from Island End River (Boston

  9. Results of bulk sediment analysis and bioassay testing on selected sediments from Oakland Inner Harbor and Alcatraz disposal site, San Francisco, California

    SciTech Connect

    Word, J Q; Ward, J A; Woodruff, D L

    1990-09-01

    The Battelle/Marine Sciences Laboratory (MSL) was contracted by the US Army Corps of Engineers, San Francisco District, to perform bulk sediment analysis and oyster larvae bioassays (elutriate) on sediments from Inner Oakland Harbor, California. Analysis of sediment characteristics by MSL indicated elevated priority pollutants, PAHs, pesticides, metals, organotins, and oil and grease concentrations, when compared to Alcatraz Island Dredged Material Disposal Site sediment concentrations. Larvae of the Pacific oyster, Crassostrea gigas, were exposed to seawater collected from the Alcatraz Island Site water, and a series of controls using water and sediments collected from Sequim Bay, Washington. Exposure of larvae to the Alcatraz seawater and the 50% and 100% elutriate concentrations from each Oakland sediment resulted in low survival and a high proportion of abnormal larvae compared to Sequim Bay control exposures. MSL identified that field sample collection, preservation, and storage protocols used by Port of Oakland contractors were inconsistent with standard accepted practices. 23 refs., 10 figs., 40 tabs.

  10. Anaerobic hydrocarbon degradation in petroleum-contaminated harbor sediments under sulfate-reducing and artificially imposed iron-reducing conditions

    USGS Publications Warehouse

    Coates, J.D.; Anderson, R.T.; Woodward, J.C.; Phillips, E.J.P.; Lovley, D.R.

    1996-01-01

    The potential use of iron(III) oxide to stimulate in-situ hydrocarbon degradation in anaerobic petroleum-contaminated harbor sediments was investigated. Previous studies have indicated that Fe(III)-reducing bacteria (FeRB) can oxidize some electron donors more effectively than sulfate- reducing bacteria (SRB). In contrast to previous results in freshwater sediments, the addition of Fe(III) to marine sediments from San Diego Bay, CA did not switch the terminal electron-accepting process (TEAP) from sulfate reduction to Fe-(III) reduction. Addition of Fe(III) also did not stimulate anaerobic hydrocarbon oxidation. Exposure of the sediment to air [to reoxidize Fe(II) to Fe(III)] followed by anaerobic incubation of the sediments, resulted in Fe-(III) reduction as the TEAP, but contaminant degradation was not stimulated and in some instances was inhibited. The difference in the ability of FeRB to compete with the SRB in the different sediment treatments was related to relative population sizes. Although the addition of Fe(III) did not stimulate hydrocarbon degradation, the results presented here as well as other recent studies demonstrate that there may be significant anaerobic hydrocarbon degradation under sulfate-reducing conditions in harbor sediments.

  11. Biological testing of sediment for the Olympia Harbor Navigation Improvement Project, 1988: Geoduck, amphipod, and echinoderm bioassays

    SciTech Connect

    Ward, J.A.; Word, J.Q.; Antrim, L.D.

    1989-05-01

    The Olympia Harbor Navigation Improvement Project requires the dredging of approximately 330,000 cubic yards (cy) of sediment from the harbor entrance channel and 205,185 cy from the turning basin. Puget Sound Dredged Disposal Analysis (PSDDA) partial characterization studies were used to plan a full sediment characterization in which chemical analyses and biological testing of sediments evaluated the suitability of the dredged material for unconfined, open-water disposal. The US Army Corps of Engineers (COE), Seattle District, contracted with NOAA/NMFS, Environmental Conservation Division, to perform the chemical analysis and Microtox bioassay tests, and with the Battelle/Marine Sciences Laboratory (MSL) in Sequim to perform flow-through solid-phase bioassays utilizing juvenile (8 to 10 mm) geoduck clams, Panopea generosa, and static solid phase bioassays using the phoxocephalid amphipod, Rhepoxynius abronius, developing embryos and gametes of the purple sea urchin, Strongylocentrotus purpuratus, and the larvae of the Pacific oyster Crassostrea gigas. When the results of the biological tests were evaluated under PSDDA guidelines, it was found that all the tested sediment treatments from Olympia Harbor are suitable for unconfined open-water disposal. 14 refs., 12 figs., 3 tabs.

  12. Composition and source apportionment of PAHs in sediments at river mouths and channel in Kaohsiung Harbor, Taiwan.

    PubMed

    Chen, Chiu-Wen; Chen, Chih-Feng; Dong, Cheng-Di; Tu, Yao-Ting

    2012-01-01

    Fifty-eight sediment samples were collected in 2009 from the bottom of river mouths near Kaohsiung Harbor (Taiwan) and the harbor channel for the analyses of polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry (GC-MS). Concentrations of total PAHs varied from 39 to 30,521 ng g(-1) (dry weight); samples collected from the mouths of Love River, Canon River, Jen-Gen River, and Salt River showed the highest PAHs concentrations. This indicates that the major sources of sediment PAHs come from those polluted urban rivers and the harbor channel. In samples collected from the Salt River mouth, approximately 43% of the PAHs are identified as PAHs with 2 or 3 rings. However, samples collected from other locations contain predominantly PAHs with 4 rings (32 to 42%) or 5 and 6 rings (36 to 44%). Emissions from traffic-related sources and waste incineration contribute to the majority of PAHs found in most channel and river mouth sediments. However, coal/oil combustion is the main cause of high concentrations of PAHs observed in the Salt River mouth sediments. Principal component analyses with multivariate linear regression (PCA/MLR) have been used to further quantify the source contributions, and the results show that the contributions of coal/oil combustion, traffic-related and waste incineration are 37%, 33% and 30%, respectively.

  13. Hydrophobic organic contaminants in surficial sediments of Baltimore Harbor: Inventories and sources

    SciTech Connect

    Ashley, J.T.F.; Baker, J.E.

    1999-05-01

    The heavily urbanized and industrialized Baltimore Harbor/Patapsco River/Back River system is one of the most highly contaminated regions of the Chesapeake Bay. In June 1996, surficial sediments were collected at 80 sites throughout the subestuarine system, including historically undersampled creek sand embayments. The samples were analyzed for a suite of hydrophobic organic contaminants (HOCs) consisting of 32 polycyclic aromatic hydrocarbons (PAHs) and 113 polychlorinated biphenyl (PCB) congeners. Total PAH and total PCB concentrations ranged from 90 to 46,200 and 8 to 2,150 ng/g dry weight, respectively. There was enormous spatial variability in the concentrations of HOCs, which was not well correlated to grain size or organic carbon content, suggesting nonequilibrium partitioning and/or proximity to sources as important factors explaining the observed spatial variability. High concentrations of both classes of HOCs were localized around major urban stormwater runoff discharges. Elevated PAH concentrations were also centered around the Sparrow`s Point Industrial Complex, most likely a result of the pyrolysis of coal during the production of steel. All but 1 of the 80 sites exceeded the effects range-low (ERL) for total PCBs and, of those sites, 40% exceeded the effects range-medium (ERM), suggesting toxicity to marine benthic organisms would frequently occur. Using principal component analysis, differences in PAH signatures were discerned. Higher molecular weight PAHs were enriched in signatures from sediments close to suspected sources (i.e., urban stormwater runoff and steel production complexes) compared to those patterns observed at sites further from outfalls or runoff. Due to varying solubilities and affinities for organic matter of the individual PAHs, partitioning of the heavier weight PAHs may enrich settling particles with high molecular weight PAHs. Lower molecular weight PAHs, having lower affinity for particles, may travel from the source to a

  14. Polychlorinated biphenyls in the surficial sediment of Indiana Harbor and Ship Canal, Lake Michigan.

    PubMed

    Martinez, Andres; Norström, Karin; Wang, Kai; Hornbuckle, Keri C

    2010-11-01

    We report the results of the first intensive survey of polychlorinated biphenyls (PCBs) in the surficial sediment of the Indiana Harbor and Ship Canal (IHSC) in East Chicago, Indiana, a part of the Calumet River tributary of Lake Michigan that will be dredged to maintain depth for ship traffic. The tributary has previously been reported to be a large source of PCBs to Lake Michigan. PCB congeners were measured using tandem mass spectrometry in multiple reaction monitoring mode, a method that provides a high level selectivity and sensitivity for PCBs in complex environmental samples. The PCB concentrations (sum of 163 congeners or coeluting peaks) range from 53 to 35,000 ng g(-1) dry weight (d.w.) and are comparable to other PCB concentrations at contaminated tributaries in the United States, most of them (although not IHSC) established by law as Superfund sites. The PCB congener signal strongly resembles the original technical mixture Aroclor 1248 that has experienced a small amount of weathering--less than 2.5% by mass for the statistically different congeners--consistent with desorption, volatilization, and microbial dechlorination. The origin of the PCBs in IHSC is not known but Aroclor 1248 was used in hydraulic fluids, vacuum pumps, plasticizers and adhesives. Possible uses of this mixture in East Chicago included the equipment and auxiliary services for the adjacent steel mill and gas refinery and/or lubrication for the drawbridges spanning the canal.

  15. Data files from the Grays Harbor Sediment Transport Experiment Spring 2001

    USGS Publications Warehouse

    Landerman, Laura A.; Sherwood, Christopher R.; Gelfenbaum, Guy; Lacy, Jessica; Ruggiero, Peter; Wilson, Douglas; Chisholm, Tom; Kurrus, Keith

    2005-01-01

    This publication consists of two DVD-ROMs, both of which are presented here. This report describes data collected during the Spring 2001 Grays Harbor Sediment Transport Experiment, and provides additional information needed to interpret the data. Two DVDs accompany this report; both contain documentation in html format that assist the user in navigating through the data. DVD-ROM-1 contains a digital version of this report in .pdf format, raw Aquatec acoustic backscatter (ABS) data in .zip format, Sonar data files in .avi format, and coastal processes and morphology data in ASCII format. ASCII data files are provided in .zip format; bundled coastal processes ASCII files are separated by deployment and instrument; bundled morphology ASCII files are separated into monthly data collection efforts containing the beach profiles collected (or extracted from the surface map) at that time; weekly surface maps are also bundled together. DVD-ROM-2 contains a digital version of this report in .pdf format, the binary data files collected by the SonTek instrumentation, calibration files for the pressure sensors, and Matlab m-files for loading the ABS data into Matlab and cleaning-up the optical backscatter (OBS) burst time-series data.

  16. Concentration, distribution, and bioavailability of mercury and methylmercury in sediments of Baltimore Harbor and Chesapeake Bay, Maryland, USA

    SciTech Connect

    Mason, R.P.; Lawrence, A.L.

    1999-11-01

    For the Chesapeake Bay, sediments in regions such as Baltimore Harbor have total mercury (Hg) concentrations that exceed environmental effects guidelines. However, fish concentrations do not appear elevated. Indeed, the factors controlling the transfer of sedimentary Hg, especially as monomethylmercury (MMHg), the most bioaccumulative form of Hg, to these aquatic organisms are poorly understood. To examine this, the authors have investigated the distribution and bioavailability of Hg and MMHg to benthic organisms in Baltimore harbor and the Chesapeake Bay, in Maryland, USA. The results discussed here show that sediment concentration for both total Hg and MMHg covaries with sediment organic content and that this parameter is a better predictor, for surface sediments, of concentration than iron content, acid volatile sulfide (AVS), or other factors. Furthermore, correlations between inorganic Hg and MMHg in benthic biota with sediment levels suggest that variation in the bioaccumulation factor (SBAF) for invertebrates is best explained in terms of sediment organic content. thus, the results from this study emphasize the importance of organic matter in regions removed from point source input in controlling both the concentration and bioavailability of MMHg to organisms. Because of the exponential nature of the SBAF/organic content relationship, there is a nonlinear organism response to MMHg in sediments that must be considered in any estimation of the toxic effect of sediment MMHg. Also, as a result of the decoupling between total Hg and MMHg concentration and bioavailability in surface sediments, any remediation evaluation of bioavailability and/or toxicity that is based only on total Hg concentration is unlikely to provide a reliable prediction.

  17. An assessment of injury to sediments and sediment-dwelling organisms in the Grand Calumet River and Indiana Harbor Area of Concern, USA

    USGS Publications Warehouse

    MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sparks, D.W.; Smith, J.R.; Simon, T.P.; Hanacek, M.A.

    2002-01-01

    This article is the first in a series of three that describe the results of a Natural Resource Damage Assessment (NRDA) conducted in the Grand Calumet River and Indiana Harbor Area of Concern (IHAOC). The assessment area is located in northwest Indiana and was divided into nine reaches to facilitate the assessment. This component of the NRDA was undertaken to determine if sediments and sediment-dwelling organisms have been injured due to exposure to contaminants that have accumulated in sediments as a result of discharges of oil or releases of other hazardous substances from industrial, municipal, and nonpoint sources. To support this assessment, information was compiled on the chemical composition of sediment and pore water; on the toxicity of whole sediments, pore water, and elutriates; and on the status of benthic invertebrate communities. The data on each of these indicators were compared to regionally relevant benchmarks to assess the presence and extent of injury to surface water resources (i.e., sediments) or biological resources (i.e., sediment-dwelling organisms). The results of this assessment indicate that sediment injury has occurred throughout the assessment area, with up to four distinct lines of evidence demonstrating injury within the various reaches. The primary contaminants of concern (i.e., those substances that are present at concentrations that are sufficient to cause or substantially contribute to sediment injury) include metals, polycyclic aromatic hydrocarbons, and total polychlorinated biphenyls.

  18. Suspended Sediment in the Indiana Harbor Canal and the Grand Calumet River, Northwestern Indiana, May 1996-June 1998

    USGS Publications Warehouse

    Renn, Danny E.

    2000-01-01

    Suspended-sediment samples and streamflow data were collected from May 1996 through June 1998 at three sites in the Grand Calumet River Basin - Indiana Harbor Canal at East Chicago, the east branch of the Grand Calumet River at Gary, and the west branch of the Grand Calumet River at Hammond. Sample analysis allowed for retention of sediments of 0.0015 millimeters or larger. At Indiana Harbor Canal at East Chicago, an automated sampler collected 2,005 suspended-sediment samples from the canal and, of these, 1,856 had associated streamflow values. To evaluate any bias between instream concentrations of suspended sediment and samples collected by the automated sampler, 27 sets of suspended-sediment samples were collected manually in the canal at the same time samples were collected by the automated sampler. There was no consistent bias between the samples collected manually instream and the samples collected by the automated sampler; therefore, no correction factor was applied to the concentrations of suspended sedment for the samples collected by the automated sampler. For the 2,005 and 1,856 samples, the mean suspended-sediment concentrations were the same, 15 milligrams per liter (mg/L), and the range in suspended-sediment concentrations were the same, from less than 1 mg/L to 97 mg/L. No apparent relation between the concentration of suspended sediment measured in samples from the Indiana Harbor Canal and streamflow was indicated, probably because of complex hydraulic conditions in the study area; most of the streamflow is from industrial and municipal discharges, and streamflow is affected by changes in water levels in Lake Michigan. There did appear to be a seasonal trend in the concentrations of suspended sediment, however, in that the largest concentrations generally were measured during the spring. During the study, four substantial rainfall events were recorded. Only for a rainfall event of 4.20 inches was there a substantial increase in the concentrations

  19. Multicriteria decision analysis to assess options for managing contaminated sediments: Application to Southern Busan Harbor, South Korea.

    PubMed

    Kim, Jongbum; Kim, Suk Hyun; Hong, Gi Hoon; Suedel, Burton C; Clarke, Joan

    2010-01-01

    Many years of untreated effluent discharge from residential areas, a shipyard, a marina, and a large fish market resulted in substantial contamination of bottom sediment in Southern Busan Harbor, South Korea. Contaminants in these sediments include heavy metals and organic compounds. Newly introduced regulations for ocean disposal of dredged material in South Korea pose significant challenges, because the previous practice of offshore disposal of contaminated dredged material was no longer possible after August 2008. The South Korean government has mandated that such sediments be assessed in a way that identifies the most appropriate dredged material management alternative, addressing environmental, social, and cost objectives. An approach using multicriteria decision analysis (MCDA) in combination with comparative risk assessment was used as a systematic and transparent framework for prioritizing several dredged sediment management alternatives. We illustrate how MCDA can recognize the multiple goals of contaminated sediment management. Values used in weighting decision criteria were derived from surveys of stakeholders who were sediment management professionals, business owners, or government decision makers. The results of the analysis showed that land reclamation was the preferred alternative among cement-lock, sediment washing, 3 contained aquatic disposal alternatives (one in combination with a hopper dredge), geotextile tubes, solidification, and land reclamation after solidification treatment. Land reclamation was the preferred alternative, which performed well across all MCDA objectives, because of the availability of a near-shore confined disposal facility within a reasonable distance from the dredging area.

  20. A toxicity identification evaluation of silty marine harbor sediments to characterize persistent and non-persistent constituents.

    PubMed

    Stronkhorst, Joost; Schot, Marlies E; Dubbeldam, Marco C; Ho, Kay T

    2003-01-01

    Sediment toxicity in silty marine harbor sediments is frequently dominated by ammonia or sulfide, leaving the adverse effects of persistent toxic substances unnoticed. To investigate the latter, we subjected interstitial water from three contaminated silty sediments to toxicity identification evaluation (TIE) phase I manipulations and tested for toxicity with four bioassays: the amphipod Corophium volutator (survival as an endpoint), the sea urchin Psammechinus miliaris (fertilization, embryo development) and the bacterium Vibrio fischeri (bioluminescence inhibition). The graduated pH manipulations identified the prominent toxicity of ammonia in the amphipod and sea urchin embryo tests, and also sulfide toxicity in the bacterium test. In two of the three samples tested with the amphipods, sea urchin embryos and bacteria, a small but significant reduction in interstitial water toxicity was achieved by removing persistent compounds through C(18) solid phase extraction. EDTA chelation resulted in a slight detoxification of the interstitial water for the amphipods and sea urchin embryos, but this was not related to any measured trace metals. Despite the presence of toxic levels of ammonia and sulfide in the harbor sediments, we established the adverse biological effects of persistent constituents by means of the TIE manipulations and in vivo interstitial water bioassays.

  1. PRELIMINARY EVALUATION OF POTENTIAL OCCUPATIONAL AND PUBLIC HEALTH IMPACTS OF SEDIMENT DECONTAMINATION FACILITIES FOR NEW YORK/NEW JERSEY HARBOR

    SciTech Connect

    ROWE,M.D.; KLEIN,R.C.; JONES,K.W.

    1999-07-31

    Sediment is accumulating in New York/New Jersey Harbor, and shipping channels are rapidly becoming too shallow for large ships. The Port Authority of New York/New Jersey has determined that dredging of the ship channels is essential to keep them navigable. About five million cubic yards of sediment must be removed per year to keep the channels open. Without dredging, the channels will soon become unusable, and the shoreside shipping and warehousing businesses that depend on them will fade away. The economic loss to the area would be devastating. But the deeper layers of sediment in the Harbor contain a broad range of pollutants that are hazardous to humans and the environment-a legacy of past discharges that are no longer permitted. These include heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated pesticides, and dioxins. As a result, there are several million cubic yards of sediments to be dredged per year that do not meet applicable criteria for ocean disposal and must be dealt with in some other way. A possible solution to the problem is to treat the dredged material to immobilize or destroy the contaminants and make the treated sediments suitable for disposal in the ocean or on land at acceptable cost. A variety of technologies can be used to achieve this goal. The simplest approach is to make manufactured soil from untreated sediment. The most complex approaches involve high-temperature destruction of organic contaminants and immobilization of inorganic contaminants. When any of these technologies are used, there is potential for risks to human health from process wastes and from the treated materials themselves. Also, disposal or beneficial use of treated materials may generate other risks to human health or the environment. A description of some of the technologies considered is given in Table 1. Success in removing or immobilizing the contaminants, which varies significantly among technologies, is reported

  2. Necessity of normalization to aluminum to assess the contamination by heavy metals and arsenic in sediments near Haiphong Harbor, Vietnam

    NASA Astrophysics Data System (ADS)

    Ho, Huu Hieu; Swennen, Rudy; Cappuyns, Valérie; Vassilieva, Elvira; Van Tran, Tan

    2012-08-01

    While assessing many different aspects of contamination by heavy metals and arsenic in sediments, the natural variability in element contents which depends on the grain-size and mineralogical composition of sediments, needs to be taken into account. In previous studies, the normalization of element contents to a reference element such as Al was commonly applied to compensate for granulometric and mineralogical effects. In the present study, through the investigation on the contamination of heavy metals and arsenic in sediments near Haiphong Harbor, the necessity of the normalization towards Al is assessed. The results indicate that before Al-normalization, the occurrences on the source and historical trend of contamination by heavy metals and arsenic can be masked by the distribution of clay (Φ < 2 μm) or fine (Φ < 63 μm) fractions as well as Al, Fe and organic matter. In contrast, after Al-normalization, spatial distribution of elements illustrates that Cr, Ni, Pb and Mn are enriched by the anthropogenic activities in the Haiphong industrial and harbor zone while As, Cd and Cu come from upstream sources, and Co and Zn indicate only locally-elevated contaminations. The vertical profile of elements in core sediments illustrates that the anthropogenic input of heavy metals and arsenic increased in recent years. Moreover, the assessment of the degree of contamination based on the Enrichment Factor (EF) and obtained local background values indicates a minor enrichment of all heavy metals and arsenic. This is not in line with the assessment based on the sediment quality guidelines or reference values from upper-continental or average-continental crust which states the "serious" contamination of Cd, Pb, Cu, Zn and especially As. Therefore, the normalization to Al is necessary in interpreting the source, historical trend and degree of contamination by heavy metals and arsenic in sediments of the study area.

  3. Substantial nitrous oxide emissions from intertidal sediments and groundwater in anthropogenically-impacted West Falmouth Harbor, Massachusetts

    USGS Publications Warehouse

    Moseman-Valtierra, Serena; Kroeger, Kevin D.; Crusius, John; Baldwin, Sandy; Green, Adrian; Brooks, Thomas W.; Pugh, E.

    2015-01-01

    Large N2O emissions were observed from intertidal sediments in a coastal estuary, West Falmouth Harbor, MA, USA. Average N2O emission rates from 41 chambers during summer 2008 were 10.7 mol N2O m(-2) h(-1)±4.43 μmol N2O m(-2) h(-1) (standard error). Emissions were highest from sediments within a known wastewater plume, where a maximum N2O emission rate was 155 μmol N2O m(-2) h(-1). Intertidal N2O fluxes were positively related to porewater ammonium concentrations at 10 and 25 cm depths. In groundwater from 7 shoreline wells, dissolved N2O ranged from 488% of saturation (56 nM N2O) to more than 13000% of saturation (1529 nM N2O) and was positively related to nitrate concentrations. Fresh and brackish porewater underlying 14 chambers was also supersaturated in N2O, ranging from 2980% to 13175% of saturation. These observations support a relationship between anthropogenic nutrient loading and N2O emissions in West Falmouth Harbor, with both groundwater sources and also local N2O production within nutrient-rich, intertidal sediments in the groundwater seepage face. N2O emissions from intertidal "hotspot" in this harbor, together with estimated surface water emissions, constituted 2.4% of the average overall rate of nitrogen export from the watershed to the estuary. This suggests that N2O emissions factors from coastal ecosystems may be underestimated. Since anthropogenic nutrient loading affects estuaries worldwide, quantification of N2O dynamics is warranted in other anthropogenically-impacted coastal ecosystems.

  4. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria.

    PubMed

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

    2012-11-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 10(6) acetate-utilizing manganese-reducing cells cm(-3) in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments.

  5. The impact of disposal of fine-grained sediments from maintenance dredging works on SPM concentration and fluid mud in and outside the harbor of Zeebrugge

    NASA Astrophysics Data System (ADS)

    Fettweis, Michael; Baeye, Matthias; Cardoso, Claudio; Dujardin, Arvid; Lauwaert, Brigitte; Van den Eynde, Dries; Van Hoestenberghe, Thomas; Vanlede, Joris; Van Poucke, Luc; Velez, Carlos; Martens, Chantal

    2016-11-01

    The amount of sediments to be dredged and disposed depends to a large part on the suspended particulate matter (SPM) concentration. Tidal, meteorological, climatological, and seasonal forcings have an influence on the horizontal and vertical distribution of the SPM in the water column and on the bed and control the inflow of fine-grained sediments towards harbors and navigation channels. About 3 million tons (dry matter) per year of mainly fine-grained sediments is dredged in the port of Zeebrugge and is disposed on a nearby disposal site. The disposed sediments are quickly resuspended and transported away from the site. The hypothesis is that a significant part of the disposed sediments recirculates back to the dredging places and that a relocation of the disposal site to another location at equal distance to the dredging area would reduce this recirculation. In order to validate the hypothesis, a 1-year field study was set up in 2013-2014. During 1 month, the dredged material was disposed at a new site. Variations in SPM concentration were related to tides, storms, seasonal changes, and human impacts. In the high-turbidity Belgian near-shore area, the natural forcings are responsible for the major variability in the SPM concentration signal, while disposal has only a smaller influence. The conclusion from the measurements is that the SPM concentration decreases after relocation of the disposal site but indicate stronger (first half of field experiment) or weaker (second half of field experiment) effects that are, however, supported by the environmental conditions. The results of the field study may have consequences on the management of disposal operations as the effectiveness of the disposal site depends on environmental conditions, which are inherently associated with chaotic behavior.

  6. Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in harbor sediments from Sea Lots, Port-of-Spain, Trinidad and Tobago

    USGS Publications Warehouse

    Mohammed, Azad; Peterman, Paul; Echols, Kathy; Feltz, Kevin; Tegerdine, George; Manoo, Anton; Maraj, Dexter; Agard, John; Orazio, Carl

    2011-01-01

    Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in nearshore marine surficial sediments from three locations in Trinidad. Sediments were sampled at Sea Lots on the west coast, in south Port-of-Spain Harbor, south of Sea Lots at Caroni Lagoon National Park, and on Trinidad's east coast at Manzanilla. Total PCB concentrations in Sea Lots sediments ranged from 62 to 601 ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8 ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145 ng/g dw, compared with 13.1 and 23.8 n/g (dw), for Caroni and Manzanilla respectively. The concentrations of PCBs and of some OCPs in sediments from Sea Lots were above the Canadian interim sediment quality guidelines. To date, this data is the first report on the levels of PCBs and other organochlorine compounds from Trinidad and Tobago.

  7. Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in harbor sediments from Sea Lots, Port-of-Spain, Trinidad and Tobago

    USGS Publications Warehouse

    Mohammed, Azad; Peterman, Paul; Echols, Kathy; Feltz, Kevin; Tegerdine, George; Manoo, Anton; Maraj, Dexter; Agard, John; Orazio, Carl

    2011-01-01

    Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in nearshore marine surficial sediments from three locations in Trinidad. Sediments were sampled at Sea Lots on the west coast, in south Port-of-Spain Harbor, south of Sea Lots at Caroni Lagoon National Park, and on Trinidad's east coast at Manzanilla. Total PCB concentrations in Sea Lots sediments ranged from 62 to 601 ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8 ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145 ng/g dw, compared with 13.1 and 23.8 n/g (dw), for Caroni and Manzanilla respectively. The concentrations of PCBs and of some OCPs in sediments from Sea Lots were above the Canadian interim sediment quality guidelines. To date, this data is the first report on the levels of PCBs and other organochlorine compounds from Trinidad and Tobago.

  8. Vertical profile, contamination assessment, and source apportionment of heavy metals in sediment cores of Kaohsiung Harbor, Taiwan.

    PubMed

    Chen, Chih-Feng; Ju, Yun-Ru; Chen, Chiu-Wen; Dong, Cheng-Di

    2016-12-01

    Six sediment cores collected at the Kaohsiung Harbor of Taiwan were analyzed to evaluate their vertical profiles, enrichments, accumulations, and source apportionments of heavy metals. This was performed to investigate any potential ecological risks posed by heavy metals. Results indicated that the mean heavy metal content (mg kg(-1)) in the six sediment cores was as follows: Hg (0.4-6.4), Cd (<0.05-2.4), Cr (18-820), Cu (16-760), Pb (31-140), and Zn (76-1900). The patterns of heavy metal content in the sediment cores differed substantially among the four river mouths. However, the vertical profiles of metals were relatively stable, indicating that wastewater has the constant characteristics and has been discharged into the rivers for a long period of time. Results of pollution assessment of enrichment factor, geo-accumulation index, and pollution load index revealed that river mouths experience severe enrichment, strong accumulation, and high contamination from the primary heavy metals. It was not consistent in the assessment results of mean effect range median quotient, potential ecological risk index, and total toxic unit method. Potential ecological risks caused by Hg in the sediments at Canon River and Love River mouths on aquatic organisms were extremely high. The estimates derived from the receptor modeling of multiple linear regression of the absolute principal component scores indicated that the contributions of the composite heavy metals derived from the Canon River and the Love River on the potential toxicity and risks to the water environment of Kaohsiung Harbor were highest, followed by those derived from Salt River and Jen-Gen River. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Effects-based spatial assessment of contaminated estuarine sediments from Bear Creek, Baltimore Harbor, MD, USA.

    PubMed

    Hartzell, Sharon E; Unger, Michael A; McGee, Beth L; Yonkos, Lance T

    2017-07-15

    Estuarine sediments in regions with prolonged histories of industrial activity are often laden to significant depths with complex contaminant mixtures, including trace metals and persistent organic pollutants. Given the complexity of assessing risks from multi-contaminant exposures, the direct measurement of impacts to biological receptors is central to characterizing contaminated sediment sites. Though biological consequences are less commonly assessed at depth, laboratory-based toxicity testing of subsurface sediments can be used to delineate the scope of contamination at impacted sites. The extent and depth of sediment toxicity in Bear Creek, near Baltimore, Maryland, USA, was delineated using 10-day acute toxicity tests with the estuarine amphipod Leptocheirus plumulosus, and chemical analysis of trace metals and persistent organic pollutants. A gradient of toxicity was demonstrated in surface sediments with 21 of 22 tested sites differing significantly from controls. Effects were most pronounced (100% lethality) at sites proximate to a historic industrial complex. Sediments from eight of nine core samples to depths of 80 cm were particularly impacted (i.e., caused significant lethality to L. plumulosus) even in locations overlain with relatively non-toxic surface sediments, supporting a conclusion that toxicity observed at the surface (top 2 cm) does not adequately predict toxicity at depth. In seven of nine sites, toxicity of surface sediments differed from toxicity at levels beneath by 28 to 69%, in five instances underestimating toxicity (28 to 69%), and in two instances overestimating toxicity (44 to 56%). Multiple contaminants exceeded sediment quality guidelines and correlated positively with toxic responses within surface sediments (e.g., chromium, nickel, polycyclic aromatic hydrocarbon (PAH), total petroleum hydrocarbon). Use of an antibody-based PAH biosensor revealed that porewater PAH concentrations also increased with depth at most sites. This

  10. Distribution of suspended sediment in a partially mixed estuary, Charleston Harbor, South Carolina, U.S.A.

    NASA Astrophysics Data System (ADS)

    Althausen, J. D.; Kjerfve, Björn

    1992-11-01

    A well-defined turbidity maximum zone (TMZ) exists 15-45 km upstream of the entrance to Charleston Harbor, South Carolina, on the Cooper River, where the salinity varies between 5-15 ppt. The TMZ is characterized by less than 60% light transmission over a 5 cm path-length near the bottom, as compared to 70-90% light transmission elsewhere. The TMZ oscillates along the Cooper River 3-13 km during a tidal cycle. The range of total suspended sediment (TSS) concentration is 40-100 mg l -1 in the TMZ, while 10-30 mg l -1 is the most common TSS concentration elsewhere in the estuarine portion of Charleston Harbor and the Cooper River. Transmissivity is well-correlated with TSS ( r2 = 0·77) throughout the estuary. TSS concentration depends largely on tidal stage and varies significantly from spring to neap tide. Spring tide TSS concentrations are 2-3 times greater than concentrations during neap tides. The net downstream transport of suspended sediment is primarily a function of fresh water discharge, but is particularly large when flood events coincide with spring tides as was evident during the sampling of the TMZ following Hurricane Hugo (22 September 1989).

  11. Distribution, origin, and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in sediments of Kaohsiung Harbor, Taiwan.

    PubMed

    Chen, Chiu-Wen; Chen, Chih-Feng

    2011-01-01

    Sediment samples were collected from 12 locations of Kaohsiung Harbor, Taiwan and analyzed for polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations varied from 472 to 16,201 ng g(-1) dry weight. The highest PAH concentrations were from the industrial zone docks situated in south Kaohsiung Harbor. Diagnostic ratios showed that the possible source of PAHs in the industrial zone dock could be coal combustion while in the other zones it could be petroleum combustion. The toxic equivalent concentrations (TEQcarc) of PAHs varied from 55 to 1964 ng TEQ g(-1) dry weight. Higher total TEQcarc values were found at industrial zone docks (from 1404 to 1964 ng TEQ g(-1) dry weight). As compared with the US Sediment Quality Guidelines (SQGs), the observed levels of PAHs at industrial zone docks exceeded the effects range low (ERL), and could thus cause acute biological damage. However, the lower levels of PAHs at the other zones would probably not exert adverse biological effects. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. CHARACTERIZATION AND FATE OF PAH-CONTAMINATED SEDIMENTS AT THE WYCKOFF/EAGLE HARBOR SUPERFUND SITE

    EPA Science Inventory

    Eagle Harbor is a shallow marine embayment of Bainbridge Island, WA and formerly the site of the Wyckoff wood-treatment facility. The facility became operational in the early 1900s and used large quantities of creosote in its wood-treating processes. Creosote percolated through t...

  13. Diversity, Abundance, and Distribution of nirS-Harboring Denitrifiers in Intertidal Sediments of the Yangtze Estuary.

    PubMed

    Zheng, Yanling; Hou, Lijun; Liu, Min; Gao, Juan; Yin, Guoyu; Li, Xiaofei; Deng, Fengyu; Lin, Xianbiao; Jiang, Xiaofen; Chen, Fei; Zong, Haibo; Zhou, Junliang

    2015-07-01

    Denitrification plays a critical role in nitrogen removal in estuarine and coastal ecosystems. In this study, the community composition, diversity, abundance, and distribution of cytochrome cd1-type nitrite reductase gene (nirS)-harboring denitrifiers in intertidal sediments of the Yangtze Estuary were analyzed using polymerase chain reaction (PCR)-based clone libraries and quantitative PCR techniques. Clone library analysis showed that the nirS-encoding bacterial biodiversity was significantly higher at the lower salinity sites than at the higher salinity sites. However, there was no significant seasonal difference in the nirS gene diversity between summer and winter. Phylogenetic analysis revealed that the nirS-harboring denitrifier communities at the study area had distinctive spatial heterogeneity along the estuary. At the lower salinity sites, the nirS-harboring bacterial community was co-dominated by clusters III and VII; while at the higher salinity sites, it was dominated by cluster I. Canonical correspondence analysis indicated that the community compositions of nirS-type denitrifiers were significantly correlated with salinity, ammonium, and nitrate. Quantitative PCR results showed that the nirS gene abundance was in the range of 1.01 × 10(6) to 9.00 × 10(7) copies per gram dry sediment, without significant seasonal variation. Among all the environmental factors, the nirS gene abundance was only significantly related to the change of salinity. These results can extend our current knowledge about the composition and dynamics of denitrification microbial community in the estuarine ecosystem.

  14. Heterotrophic Activity Throughout a Vertical Profile of Seawater and Sediment in Halifax Harbor, Canada

    PubMed Central

    Novitsky, James A.

    1983-01-01

    The relative heterotrophic activity of marine microorganisms was determined at two sites by the heterotrophic uptake technique throughout the water column, the sediment-water interface, and the surface layer of sediment. In the water column, uptake was greatest at the surface and steadily decreased with depth. The percentage of the substrate that was respired also decreased with depth from 69 to 56%. The activity of the sediment-water interface was several orders of magnitude greater than that of the overlying water and twice that of the sediment immediately below. Hand-collected water samples carefully taken as close as 1 cm from the sediment-water interface had the same characteristically low activity as the bottom few meters of water. Microautoradiography with 3H-labeled glucose, glutamic acid, or thymidine revealed a general decrease in the percentage of active cells with depth from 35 to <1%. The number of active cells in the interface and sediment averaged <10% of the total population. The data indicate that the sediment-water interface is the most active region in this system due to an increased number of active cells rather than an increased percentage of active cells or increased per-cell activity. PMID:16346309

  15. Evaluation of treatment, disposal, and managerial options for dredged sediments from Newark Bay, Arthur Kill, and Newton Creek of New York/New Jersey Harbor and proposed design

    SciTech Connect

    Goswami, A.; Clesceri, N.; Preiss, I.; Stern, E.; Jones, K.; Donato, K.

    1996-11-01

    The bay areas surrounding New York/New Jersey Harbor are naturally shallow, acting as catchments for river-transported sediments and solids from surface point and nonpoint sources. Dredging is required to maintain navigability for large cargo ships. Annually more than 5 million yd{sup 3} of sediments has been dredged to maintain harbors and waterways for New York and New Jersey Harbor. Currently about 80% of dredge sediments are considered clean and ocean disposed of at the designated Mud Dump site, located approximately 6 nautical miles south of Rockaways. In order to be disposed of at the Mud Dump site, the Marine Protection, Research and Sanctuaries Act of 1972 (MPRSA) requires the evaluation of the environmental impact using criteria developed by the USEPA and published through 40 CFR Parts 220 to 228. Based on the results of the evaluation, the sediments are assigned one of three categories which defines their potential disposal method--Category 1 sediments (acceptable for ocean disposal), Category 2 sediments (acceptable for ocean disposal with specific mitigation), and Category 3 sediments (not permitted for ocean dumping). A growing public concern over the impacts of contaminated sediments, in addition to a more stringent set of criteria having been established, is expected to significantly increase the volume of sediments requiring special handling or disposal, due to the inability to dispose of Category 3 sediments at the Mud Dump Site. Hence, the objective of this project is to study the contaminant characteristics of sediments in the Newark Bay, Arthur Kill, and Newtown Creek area and identify and evaluate alternative methods for managing or decontaminating sediments that are practical, cost-effective, and protective of human health and the environment.

  16. Toxicity assessment of sediments from the Grand Calumet River and Indiana Harbor Canal in northwestern Indiana, USA

    USGS Publications Warehouse

    Ingersoll, C.G.; MacDonald, D.D.; Brumbaugh, W.G.; Johnson, B.T.; Kemble, N.E.; Kunz, J.L.; May, T.W.; Wang, N.; Smith, J.R.; Sparks, D.W.; Ireland, D.S.

    2002-01-01

    The objective of this study was to evaluate the toxicity of sediments from the Grand Calumet River and Indiana Harbor Canal located in northwestern Indiana, USA. Toxicity tests used in this assessment included 10-day sediment exposures with the amphipod Hyalella azteca, 31-day sediment exposures with the oligochaete Lumbriculus variegatus, and the Microtox® Solid-Phase Sediment Toxicity Test. A total of 30 sampling stations were selected in locations that had limited historic matching toxicity and chemistry data. Toxic effects on amphipod survival were observed in 60% of the samples from the assessment area. Results of a toxicity test with oligochaetes indicated that sediments from the assessment area were too toxic to be used in proposed bioaccumulation testing. Measurement of amphipod length after the 10-day exposures did not provide useful information beyond that provided by the survival endpoint. Seven of the 15 samples that were identified as toxic in the amphipod tests were not identified as toxic in the Microtox test, indicating that the 10-day H. azteca test was more sensitive than the Microtox test. Samples that were toxic tended to have the highest concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). The toxic samples often had an excess of simultaneously extracted metals (SEM) relative to acid volatile sulfide (AVS) and had multiple exceedances of probable effect concentrations (PECs). Metals may have contributed to the toxicity of samples that had both an excess molar concentration of SEM relative to AVS and elevated concentrations of metals in pore water. However, of the samples that had an excess of SEM relative to AVS, only 38% of these samples had elevated concentration of metals in pore water. The lack of correspondence between SEM-AVS and pore water metals indicates that there are variables in addition to AVS controlling the concentrations of metals in pore water. A mean PEC quotient of 3

  17. Distribution and source apportionment of polycyclic aromatic hydrocarbons in surface sediments from Zhoushan Archipelago and Xiangshan Harbor, East China Sea.

    PubMed

    Wang, Xiaoyan; Xu, Huanzhi; Zhou, Yongdong; Wu, Changwen; Kanchanopas-Barnette, Praparsiri

    2015-12-30

    Zhoushan Archipelago and the adjacent Xiangshan Harbor are important commercial, tourism, fishing, and mariculture areas. Considering the concern on the effects of anthropogenic activities on the environment, the level and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments were investigated. The sum of 16 PAH (∑16 PAH) concentrations in the Zhoushan Archipelago ranged from 3.67 to 31.30 ng g(-1) d.w., with a mean of 15.01 ± 1.21 ng g(-1) d.w., and that in Xiangshan Harbor varied from 11.58 to 481.44 ng g(-1) d.w., with a mean of 62.52 ± 32.85 ng g(-1) d.w. Diagnostic ratios and factor analysis were performed to identify PAH sources. Results show that PAHs have mixed origins (i.e., traffic-related sources, coal combustion, petrogenic sources, and biomass burning), with pyrolytic-related pollution as the dominant source. This study provided a baseline to promote environmental protection and pollution episode monitoring in the East China Sea. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Integrated sediment decontamination for the New York/New Jersey Harbor

    SciTech Connect

    Stern, W.A.; Donato, K.R.; Clesceri, N.L.; Jones, K.W.

    1998-02-01

    Disposal of dredged material taken from the New York/New Jersey (NY/NJ) Harbor is problematic because of the presence of inorganic and organic contaminants that under revised testing criteria render it unsuitable for return to the ocean or for beneficial reuse. Decontamination of the dredged material followed by beneficial reuse is one attractive component of the overall comprehensive dredged material management plan being developed by the US Army Corps of Engineers New York District. A demonstration program to validate decontamination processes and to bring them into full-scale use in the NY/NJ Harbor is now in progress. Tests of selected technologies have been completed at the bench scale and pilot-scale (2--15 m{sup 3}) levels. Procedures for demonstration testing on scales from 750 m{sup 3} to 75,000 m{sup 3} are being developed with the goal of producing a useable decontamination system by the end of 1999. The overall project goals and present status of the project are reviewed here.

  19. Sediment toxicity in the Duluth-Superior Harbor: Use of Microtox{reg_sign} and Mutatox{reg_sign} as screening assays

    SciTech Connect

    Schubauer-Berigan, M.; Hubbard, C.; Schubauer-Berigan, J.; Tesser, G.

    1995-12-31

    Sediment toxicity tests were conducted in the Duluth-Superior Harbor at 40 sites as part of an integrated sediment assessment during the fall of 1993. Two rapid assays conducted with Photobacterium phosphoreum (Microtox{reg_sign} and Mutatox{reg_sign}) were compared with three standard US EPA sediment toxicity tests: Hyalella azteca (acute tests) and Chironomus tentans (acute and sub-lethal tests). The response in the two microbial assays was also evaluated for sensitivity to various contaminants analyzed simultaneously in the Duluth-Superior Harbor sediments. Microtox{reg_sign} and Mutatox{reg_sign} were found to be sensitive to approximately one-third and one-half the sediments, respectively; Chironomus tentans was sensitive to 15% of the sediments (either acutely or sub-lethally), while Hyalella azteca was not sensitive to any of the sediments. In almost all cases, Microtox{reg_sign} and Mutatox{reg_sign} correctly identified samples that were toxic to the chironomid, making it useful as a screening tool for toxicity, to reduce the number of sites to be tested with the benthic organisms. The subsequent application of Microtox{reg_sign} as a screen for sediment toxicity in an EMAP survey in the St. Louis River (MN) estuary will be discussed. Correlation of Microtox{reg_sign} and Mutatox{reg_sign} toxicity to environmental contaminants found in the sediments will be presented.

  20. Genotoxicity of field-collected inter-tidal sediments from Cork Harbor, Ireland, to juvenile turbot (Scophthalmus maximus L.) as measured by the Comet assay.

    PubMed

    Kilemade, M F; Hartl, M G J; Sheehan, D; Mothersill, C; Van Pelt, F N A M; O'Halloran, J; O'Brien, N M

    2004-01-01

    The alkaline single cell gel electrophoresis (SCGE) or Comet assay was employed to test the potential of surficial sediment collected from Cork Harbor, Ireland, to induce DNA damage in turbot (Scophthalmus maximus L.) in a laboratory exposure experiment. Turbot were exposed for 21 days to field-collected sediment from Cork Harbor and from a relatively clean reference site at Ballymacoda and sampled at 0, 7, 14, and 21 days. As a positive control for the sediment exposure experiment, a subsample of the turbot was exposed to cadmium chloride-spiked seawater. DNA damage analysis was performed on epidermal, gill, spleen, liver, and whole blood cell preparations. Liver, gill, and blood were the most sensitive tissues while a lower level of damage was detected in the epidermis and spleen. The blood was determined to be a suitable predictor of DNA damage in the whole organism. Chemical analysis of the sediment indicated that polycyclic aromatic hydrocarbons formed the bulk of the contaminants, with the harbor sites having almost double the levels of those from the reference site. The data indicated that turbot exposed to sediments from Cork Harbor elicited a significant increase in DNA damage in comparison with those exposed to sediment from the reference site and that exposure to the contaminated sediments caused a multi-organ genotoxic response. Results from the study indicate a relationship between the presence of genotoxicants in sediment and DNA damage. This finding was encouraging with regard to the potential use of the Comet assay as part of a marine biomonitoring strategy.

  1. Pathway Ranking for In-place Sediment Management (CU1209). Site 2 Report - Pearl Harbor

    DTIC Science & Technology

    2006-04-01

    flux of pore water through sediment caps. Dredging 󈨢. Myers, A.C. 1979. Summer and winter burrows of a mantis shrimp , Squilla empusa, in...Point are associated with the mound opening of burrowing shrimp . (Scale: Width of image = 15 cm...to ghost shrimp activities (Scale: Width of image = 15 cm

  2. LAND TREATMENT OF MILWAUKEE HARBOR SEDIMENTS CONTAMINATED WITH PAHS AND PCBS

    EPA Science Inventory

    Sediments dredged in the maintenance of navigation channels often contain concentrations of PCBs and PAHs that necessitate placement in confined disposal facilities (CDFs). For the Great Lakes especially, the majority of CDFs were constructed in the 1970s or early 1980s and have ...

  3. Geotechnical and Geoacoustic Investigation of Seafloor Sediments on Boston Harbor Approaches

    DTIC Science & Technology

    2017-01-25

    26 Appendix A STING data – bearing strength profiles with depth. Box 1. .............................. 27 1...in conducting sediment analysis for bearing strength. These probes consist of a fin- stabilized main body with extension/penetrator rods attached to...If large enough layers of sandy material are present, they result in characteristic spikes in acceleration (and this bearing strength) records, due to

  4. LAND TREATMENT OF MILWAUKEE HARBOR SEDIMENTS CONTAMINATED WITH PAHS AND PCBS

    EPA Science Inventory

    Sediments dredged in the maintenance of navigation channels often contain concentrations of PCBs and PAHs that necessitate placement in confined disposal facilities (CDFs). For the Great Lakes especially, the majority of CDFs were constructed in the 1970s or early 1980s and have ...

  5. Capping in situ with activated carbon in Trondheim harbor (Norway) reduces bioaccumulation of PCBs and PAHs in marine sediment fauna.

    PubMed

    Samuelsson, Göran S; Hedman, Jenny E; Elmquist Kruså, Marie; Gunnarsson, Jonas S; Cornelissen, Gerard

    2015-08-01

    Three types of thin-layer caps with activated carbon (AC) were tested in situ in experimental plots (10 × 10 m) in Trondheim harbor, Norway, using AC + clay, AC-only or AC + sand. One year after capping, intact sediment cores were collected from the amended plots for ex situ surveys of the capping efficiency in reducing the PAH and PCB aqueous concentrations and bioaccumulation by the polychaete Hediste diversicolor and the clam Abra nitida. Reduced pore water concentrations were observed in all AC treatments. The capping efficiency was in general AC + clay > AC-only > AC + sand. AC + clay reduced bioaccumulation of PAH and PCB congeners between 40% and 87% in the worms and between 67% and 97% in the clams. Sediment capped with AC-only also led to reduced bioaccumulation of PCBs, while AC + sand showed no reduction in bioaccumulation. Thus the best thin-layer capping method in this study was AC mixed with clay.

  6. A Method to Forecast Sedimentation Rates Resulting From the Settlement of Suspended Solids within Semienclosed Harbors.

    DTIC Science & Technology

    1981-06-01

    JUN Al C H EVERTS UNCLASSIFIED CERC- CETA -81-6 *f f f f . f f 98i LEY~kF ETA 81-6 A Method to Forecast Sedimentation Rates S ’~ Resulting from the...REPORT NUMBER 2. GOVT ACCESSION NO. 3, RECIPIENT’S CATALOG NUMBER CETA 81-b . I’- ( 4. TITLE (and Subtle). S. TYPE OF REPrj & PA&OO COULD - _astal

  7. Levels and mass burden of DDTs in sediments from fishing harbors: the importance of DDT-containing antifouling paint to the coastal environment of China.

    PubMed

    Lin, Tian; Hu, Zhaohui; Zhang, Gan; Li, Xiangdong; Xu, Weihai; Tang, Jianhui; Li, Jun

    2009-11-01

    DDT remains an important type of persistent organic pollutant (POP) in the environment of China. One of the current applications of DDT in China has been through antifouling paint for fishing ships as an active component. It has been estimated that approximately 5000 t of DDT was released into the Chinese coastal environment during the last two decades. Therefore, sediments in coastal fishing harbors of China may be the important sinks of DDT. In this study, DDT and its metabolites in 58 sediment samples from nine typical fishing harbors along the coastal line of China were characterized to assess their accumulation levels, sediment burdens, and potential ecological risks. The concentrations of DDTs ranged from 9 to 7350 ng/g dry weight, which were generally 1-2 orders of magnitude higher than those of the adjacent estuarine/marine sediments. The high concentrations of DDT coupled with the lower concentrations of HCH and TOC clearly indicated a strong local DDT input, i.e., DDT-containing antifouling paint, within the fishing harbors. A significant correlation between the total DDT concentrations and p,p'-DDT concentrations further confirmed the existence of fresh DDT input. The overall burden of DDTs within the upper 10 cm sediment layer in the fishing harbors of the Pearl River Delta, southern China, was estimated to be 1.0-5.7 t, which was several times higher than the DDT accumulation in the surface sediment of the Pearl River estuary. The concentrations of DDTs in the fishing harbor sediments significantly exceeded the sediment quality guidelines on the basis of adverse biological effects. The absence or low concentrations of p,p'-DDD in aquatic organisms and human may imply that either p,p'-DDD may be less bioaccumulated by fish and human, or is biotransformed to other metabolites. A national ban of DDT as an additive to antifouling paint was implemented in 2009 in China; however, the legacy high DDT burden in the coastal fishing harbors needs further

  8. Microbial diversity in polluted harbor sediments I: Bacterial community assessment based on four clone libraries of 16S rDNA

    NASA Astrophysics Data System (ADS)

    Zhang, Wen; Ki, Jang-Seu; Qian, Pei-Yuan

    2008-02-01

    Bacteria, as the most abundant sediment organism, play a major role in the fate of pollutants. Therefore, many pollutant-related bacteria have been studied in harbor sediments, yet the entire bacterial profiles have not been reported. The bacterial diversity and community structures from sediments in Victoria Harbor (Hong Kong), including two polluted (VH and VHW) and two adjacent (open oceanic, TLC; estuary discharge affected, PC) sites, were characterized by analyses of four 16S rDNA clone libraries. Upon comparisons of RFLP patterns from 254 clones in the libraries, 178 unique phylotypes were retrieved. LIBSHUFF and Rarefaction analyses indicated that the sediment bacterial communities at the four sites showed high 16S rDNA richness and were significantly different from each other. Phylogenetic analysis of full-length 16S rDNA revealed 19 bacterial phyla in Victoria Harbor sediments. γ- and δ-proteobacteria, holophaga/acidobacteria, and planctomycetales were recorded in all the libraries. In addition, γ- and δ-proteobacteria were dominant at all sites (33.33-11.67%). Besides these two phyla, ɛ-proteobacteria, firmicutes, aminobacterium, holophaga/acidobacteria and bacteroidetes were judged to be major components of a given library since they constituted 10% or more of the total OTUs of the given library. The cyanobacteria, verrucomicrobia, β-proteobacteria, aminobacterium, chlorofiexi, and candidate division OP1, OP8 were detected in minor proportions in various libraries. A portion of the clones were only distantly related to sequences in the GenBank, suggesting bacteria in Victoria Harbor sediments were unique and diversified.

  9. Results of chemical, toxicological, and bioaccumulation evaluations of dioxins, furans, and guaicol/organic acids in sediments from the Grays Harbor/Chehalis River area

    SciTech Connect

    Word, J.Q.; Ward, J.A.; Squires, A.L.

    1990-09-01

    The Battelle/Marine Sciences Laboratory (MSL) was requested by the US Army Corps of Engineers (USACE), Seattle District, to assist in planning and conducting sampling, toxicological tests, and chemistry evaluations on sediment samples collected from the Chehalis River in Grays Harbor, Washington. The objectives of the study were to investigate the toxicity and biological effects of sediments that might potentially contain dioxins, furans, and organic acids, as a result of industrial practices in the Grays Harbor area, on sensitive marine species. In addition to the toxicological tests conducted using standard bioassays, sediment chemistry tests were performed to determine levels of selected chemicals, and elutriates of sediments were tested chemically and biologically to determine contaminant mobility in water. Also, bioaccumulation measurements were made to determine chemical mobility in animal tissue. A joint task group, including representatives from the USACE, Washington Department of Ecology (WDOE), Washington Department of Natural Resources (WDNR), Washington Department of Fisheries (WDOF), and Region 9 of the US Environmental Protection Agency (USEPA) participated in designing the testing program and reviewing data produced by MSL. The results of this analysis will be included in a supplemental Environmental Assessment (EA) prepared by the USACE for the Grays Harbor Dredging Program, beginning in early 1990. 13 refs., 5 figs., 8 tabs.

  10. A summary of chemical and biological testing of proposed disposal of sediment from Richmond Harbor relative to the Deep Off-Shelf Reference Area, the Bay Farm Borrow Area, and the Alcatraz Environs Reference Area

    SciTech Connect

    Mayhew, H.L.; Karle, L.M.; Gruendell, B.D.; Pinza, M.R.

    1993-12-01

    The US Army Corps of Engineers was authorized to dredge Richmond Harbor to accomodate large, deep-draft vessels. An ecological evaluation of the Harbor sediments was performed describing the physical characteristics, toxic substances, effects on aquatic organisms,and potential for bioaccumulation of chemical contaminants. The objective of this report is to compare the sediment chemistry, acute toxicity, and bioaccumulation results of the Richmond Harbor sediments to each of the reference areas; i.e., the Deep Off-Shelf Reference Area, the Bay Farm Borrow Area, and the Alcatraz Environs Reference Area. This report will enable the US Army Corps of Engineers to determine whether disposal at a reference area is appropriate for all or part of the dredged material from Richmond Harbor. Chemical analyses were performed on 30 sediment samples; 28 of those samples were then combined to form 7 composites. The seven composites plus sediment from two additional stations received both chemical and biological evaluations.

  11. Diffuse flow environments within basalt- and sediment-based hydrothermal vent ecosystems harbor specialized microbial communities.

    PubMed

    Campbell, Barbara J; Polson, Shawn W; Zeigler Allen, Lisa; Williamson, Shannon J; Lee, Charles K; Wommack, K Eric; Cary, S Craig

    2013-01-01

    Hydrothermal vents differ both in surface input and subsurface geochemistry. The effects of these differences on their microbial communities are not clear. Here, we investigated both alpha and beta diversity of diffuse flow-associated microbial communities emanating from vents at a basalt-based hydrothermal system along the East Pacific Rise (EPR) and a sediment-based hydrothermal system, Guaymas Basin. Both Bacteria and Archaea were targeted using high throughput 16S rRNA gene pyrosequencing analyses. A unique aspect of this study was the use of a universal set of 16S rRNA gene primers to characterize total and diffuse flow-specific microbial communities from varied deep-sea hydrothermal environments. Both surrounding seawater and diffuse flow water samples contained large numbers of Marine Group I (MGI) Thaumarchaea and Gammaproteobacteria taxa previously observed in deep-sea systems. However, these taxa were geographically distinct and segregated according to type of spreading center. Diffuse flow microbial community profiles were highly differentiated. In particular, EPR dominant diffuse flow taxa were most closely associated with chemolithoautotrophs, and off axis water was dominated by heterotrophic-related taxa, whereas the opposite was true for Guaymas Basin. The diversity and richness of diffuse flow-specific microbial communities were strongly correlated to the relative abundance of Epsilonproteobacteria, proximity to macrofauna, and hydrothermal system type. Archaeal diversity was higher than or equivalent to bacterial diversity in about one third of the samples. Most diffuse flow-specific communities were dominated by OTUs associated with Epsilonproteobacteria, but many of the Guaymas Basin diffuse flow samples were dominated by either OTUs within the Planctomycetes or hyperthermophilic Archaea. This study emphasizes the unique microbial communities associated with geochemically and geographically distinct hydrothermal diffuse flow environments.

  12. Diffuse flow environments within basalt- and sediment-based hydrothermal vent ecosystems harbor specialized microbial communities

    PubMed Central

    Campbell, Barbara J.; Polson, Shawn W.; Zeigler Allen, Lisa; Williamson, Shannon J.; Lee, Charles K.; Wommack, K. Eric; Cary, S. Craig

    2013-01-01

    Hydrothermal vents differ both in surface input and subsurface geochemistry. The effects of these differences on their microbial communities are not clear. Here, we investigated both alpha and beta diversity of diffuse flow-associated microbial communities emanating from vents at a basalt-based hydrothermal system along the East Pacific Rise (EPR) and a sediment-based hydrothermal system, Guaymas Basin. Both Bacteria and Archaea were targeted using high throughput 16S rRNA gene pyrosequencing analyses. A unique aspect of this study was the use of a universal set of 16S rRNA gene primers to characterize total and diffuse flow-specific microbial communities from varied deep-sea hydrothermal environments. Both surrounding seawater and diffuse flow water samples contained large numbers of Marine Group I (MGI) Thaumarchaea and Gammaproteobacteria taxa previously observed in deep-sea systems. However, these taxa were geographically distinct and segregated according to type of spreading center. Diffuse flow microbial community profiles were highly differentiated. In particular, EPR dominant diffuse flow taxa were most closely associated with chemolithoautotrophs, and off axis water was dominated by heterotrophic-related taxa, whereas the opposite was true for Guaymas Basin. The diversity and richness of diffuse flow-specific microbial communities were strongly correlated to the relative abundance of Epsilonproteobacteria, proximity to macrofauna, and hydrothermal system type. Archaeal diversity was higher than or equivalent to bacterial diversity in about one third of the samples. Most diffuse flow-specific communities were dominated by OTUs associated with Epsilonproteobacteria, but many of the Guaymas Basin diffuse flow samples were dominated by either OTUs within the Planctomycetes or hyperthermophilic Archaea. This study emphasizes the unique microbial communities associated with geochemically and geographically distinct hydrothermal diffuse flow environments. PMID

  13. Bacterial Metabolism, Aromatic Biodegradation, and Lignin Biogeochemistry in Sediment Cores from Pearl Harbor, Hawaii

    DTIC Science & Technology

    2006-05-31

    is heavily urbanized and much of the angiosperm signal at the South Loch may be due to upland drainage in the subwatershed, whereas Bishop’s Point is...South Loch has more influence from angiosperm tissue than does Bishop’s Point, especially relative to station Table 1 — Summary of Lignin-derived...only in angiosperms C Cinnamyl family Synthesized only in nonwoody tissues (leaves, needles) S/V Ratio of syringyl to vanillyl phenols Values > 0 if

  14. Using the dioxin receptor-CALUX in vitro bioassay to screen marine harbor sediments for compounds with a dioxin-like mode of action.

    PubMed

    Stronkhorst, Joost; Leonards, Pim; Murk, Albertinka J

    2002-12-01

    The presence of dioxin-like compounds in sediments from harbors and reference sites along the Dutch coast was investigated using the dioxin receptor-chemically activated luciferase gene expression (DR-CALUX) bioassay. The DR-CALUX response varied between 0.2 and 136 ng/kg dry weight expressed in units of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency quotients (TEQ). The highest CALUX-TEQ values (> 50 ng TEQ/kg dry wt) were found in sediments from the center of the Port of Rotterdam and from the North Sea canal near Amsterdam. The DR-CALUX activity of harbor sediments was classified by setting guideline values. None of the 257 harbor sediment samples investigated exceeded the maximum value of 1,000 ng TEQ/ kg, while 94% of the samples fail the target value of 2 ng TEQ/kg. Threshold values (25 and 50 ng TEQ/kg) are intended as pass/ fail criteria for offshore disposal of dredged material and were exceeded in 12 and 3% of the samples, respectively. DR-CALUX response did not always match with contamination of polychlorinated biphenyls (PCBs) as determined in bulk sediments (sigma7-PCB ranging from < 1 to 456 microg/kg dry wt). Concentrations of planar PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated-dibenzofuranes (PCDFs), polybrominated biphenyls (PBBs), and polybrominated-diphenylethers (PBDEs) were determined in 20 selected sediment extracts. On average, PCDD/Fs explained 50% of the DR-CALUX activity and planar PCBs 6%. Further research is needed to elucidate the unexplained part of the DR-CALUX response. The DR-CALUX is a highly sensitive and reproducible bioassay that can usefully complement standard PCB analysis, improving the hazard assessment of the disposal of dredged material in the North Sea.

  15. Summary of oceanographic measurements for characterizing light attenuation and sediment resuspension in the Barnegat Bay-Little Egg Harbor Estuary, New Jersey, 2013

    USGS Publications Warehouse

    Dickhudt, Patrick J.; Ganju, Neil K.; Montgomery, Ellyn T.

    2015-08-28

    The U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection, measured suspended-sediment concentrations, currents, waves, light attenuation, and a variety of other water-quality parameters in the summer of 2013 in Barnegat Bay-Little Egg Harbor, New Jersey. These measurements quantified light attenuation and sediment resuspension in three seagrass meadows. Data were acquired sequentially at three paired channel-shoal sites, as the equipment was moved from south to north in the estuary. Data were collected for approximately 3 weeks at each site.

  16. Influence of Harbor construction on downcoast morphological evolution: Santa Barbara, California

    USGS Publications Warehouse

    Revell, D.L.; Barnard, P.L.; Mustain, N.; Storlazzi, C.D.

    2008-01-01

    Sand impoundment caused by construction of the Santa Barbara Harbor in the 1920s, created an erosion wave that impacted downcoast Carpinteria Beach. Historic beach and shoreline changes were analyzed to understand continuing erosion using a combination of historic air photos, lidar, and physical measurements. The long-term analyses show a clockwise rotation with erosion of - 0.35 m/yr at the updrift end and accretion downdrift of 0.3 m/yr. Storm impacts measured before and after the 1982-83 and 1997-98 El Ni??o events show similar rotation patterns, providing evidence that El Ni??os may be driving coastal evolution. Differences in shoreline responses between El Nino events show that the erosion hotspot migrated downdrift following construction of a revetment after the 1982-83 storms. Seasonal field measurements in the winter show beach narrowing while sediment coarsen variably alongshore. The coarsest materials and erosion hotspot are co-located at the end of the revetment on the city beach. Copyright ASCE 2008.

  17. Microbial diversity in polluted harbor sediments II: Sulfate-reducing bacterial community assessment using terminal restriction fragment length polymorphism and clone library of dsrAB gene

    NASA Astrophysics Data System (ADS)

    Zhang, Wen; Song, Lin-sheng; Ki, Jang-Seu; Lau, Chun-Kwan; Li, Xiang-Dong; Qian, Pei-Yuan

    2008-02-01

    Sulfate-reducing bacteria (SRB) are important regulators of a variety of processes in coastal marine sediments regarding organic matter turnover, biodegradation of pollutants, and sulfur and carbon cycles. Yet their community compositions have not been investigated in polluted harbor sediments. This study described the diversity and spatial variation of SRB communities in surface sediments in Victoria Harbor, Hong Kong. The spatial variation of SRB communities was described by terminal restriction fragment length polymorphism (T-RFLP). The results showed that the most diversified terminal restriction fragments were found at polluted sites. In addition, cluster analysis indicated that although the SRB communities were different at the two polluted sites, they were still more similar to each other than to the two more distant reference sites. Based on a dsrAB clone library constructed at a polluted site, diversified SRB were found, represented by 30 Operational Taxonomic Units (OTUs). Upon comparisons among the SRB sequences detected from this study and those in the GenBank, five clades of SRB were found. Three clades belonged to the known families Desulfobacteraceae, Desulfobulbaceae, and Syntrophobacteriaceae. The majority of sequenced clones, which distantly related to sequences in the GenBank, constituted the remaining two unclassified groups, suggesting unique SRB members related to the polluted harbor environment. Statistical analyses indicated that estimated SRB richness correlated with environment factors such as sulfur content, acid volatile sulfate, and redox potential.

  18. Beneficial reuse of Brest-Harbor (France)-dredged sediment as alternative material in road building: laboratory investigations.

    PubMed

    Maherzi, Walid; Benzerzour, Mahfoud; Mamindy-Pajany, Yannick; van Veen, Eleanor; Boutouil, Mohamed; Abriak, Nor Edine

    2017-04-09

    The scarcity of natural aggregates promotes waste reuse as secondary raw material in the field of civil engineering. This article focuses on the beneficial reuse of marine-dredged sediments in road building. Thus, mixtures of raw sediments and dredged sand collected from Brest Harbur (Bretagne, France) were treated with road hydraulic binders. Formulation were prepared and characterized as recommended by the French Technical Guidelines for soil treatment with lime and/or hydraulic binders. Mechanical resistance results are quite similar for both the hydraulic binders, suggesting a similar reactivity with the studied sediment sample. However, some discrepancies can be noted on sustainability parameters. Indeed, water resistance after immersion at 40°C is significantly better for the mixtures treated with cement containing more glass-forming oxides (SiO2 + Al2O3) and fluxing (Fe2O3+CaO + MgO + K2O + Na2O). Moreover, the both hydraulic binders can lead to swelling in the road materials as observed in scanning electron microscopy analyses. Indeed, microscopic observations indicated volumetric swelling of treated samples, which is greatly influenced on the one side by ettringite quantity and on the other hand by the presence of water in pores material.

  19. Accelerated Implementation of Harbor Processes Research

    DTIC Science & Technology

    2006-05-31

    WATERSHEDS, *BIODEGRADATION, *SEDIMENTS, INDUSTRIES, STRATEGY, WATER, NAVY, SITES, SEASONAL VARIATIONS, SAMPLING, CONTAMINANTS, HARBORS, OCEAN BOTTOM, ANALYTICAL CHEMISTRY , TOXICOLOGY, OCEANOGRAPHY, ESTUARIES.

  20. Evaluation of Sediment Agitation and Mixing Into the Surrounding Water Column From Capping Activities – Boston Harbor

    EPA Science Inventory

    Capping is a common remediation technology for the containment of contaminated sediments. While capping is a common remediation technology for contaminated sediments, little information exists on the potential release of contaminated sediments during and after the capping operati...

  1. Evaluation of Sediment Agitation and Mixing Into the Surrounding Water Column From Capping Activities – Boston Harbor

    EPA Science Inventory

    Capping is a common remediation technology for the containment of contaminated sediments. While capping is a common remediation technology for contaminated sediments, little information exists on the potential release of contaminated sediments during and after the capping operati...

  2. Application of a crustacean bioassay to evaluate a multi-contaminated (metal, PAH, PCB) harbor sediment before and after electrokinetic remediation using eco-friendly enhancing agents.

    PubMed

    Tian, Y; Boulangé-Lecomte, C; Benamar, A; Giusti-Petrucciani, N; Duflot, A; Olivier, S; Frederick, C; Forget-Leray, J; Portet-Koltalo, F

    2017-12-31

    Electrokinetic (EK) remediation can be a suitable technology for treating contaminated dredged harbor sediment, stored on terrestrial disposal sites. Citric acid (CA) and biosurfactants (rhamnolipids and saponin) were chosen as enhancing agents for simultaneous metal (Cd, Cr, Cu, Pb, Zn) and PAH/PCB removal by EK because of their potential low toxicity with a view to site restoration. Three EK runs were performed using a periodic voltage (1Vcm(-1)) and various concentrations of agents. The best combination of CA (0.2molL(-1)) and saponin (0.85gL(-1)) did not remove high amounts of metals (4.4-15.8%) and provided only slightly better results for PAH and PCB removal (29.2% and 38.2%, respectively). The harbor sediment was highly resistant to metal and organics mobilization and transport because of an aged contamination, a high buffering capacity, a very low hydraulic permeability and a high organic matter content. The efficiency of the EK process was also assessed by measuring the acute toxicity of the EK-treated sediment on E. affinis copepods exposed to sediment elutriates. Fortunately, the use of CA and biosurfactants did not significantly impact on sediment toxicity. Some treated sediment sections, particularly those near the anode compartment, were statistically more toxic than the raw sediment. More particularly, E. affinis copepods were significantly sensitive to low pH values and oxidative conditions, to Cu, and to a lesser extent to Pb amounts. The speciation of these metals probably changed in these pH and redox conditions so that they became more easily leachable and bioavailable. In contrast, toxicity was negatively correlated to PAH and PCB amounts after EK treatment, probably due to the production of oxidized metabolites of PAHs and PCBs. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Bioaccumulation potential of contaminants from bedded and suspended Oakland Harbor deepening project sediments to San Francisco Bay flatfish and bivalve mollusks. Final report

    SciTech Connect

    McFarland, V.A.; Clarke, J.U.; Lutz, C.H.; Jarvis, A.S.; Mulhearn, B.

    1994-08-01

    The Oakland Harbor Deepening Project (OHDP) has been on hold since 1987 due to public and resource agency concerns regarding further disposal of dredged sediments within San Francisco (SF) Bay. Dispersal of the fines fraction throughout the Bay was thought to occur following disposal operations at the Alcatraz site, resulting in transport of contaminants throughout the Bay system. The study described in this report was designed to address the potential for contaminant uptake in estuarine organisms through exposure to suspended and bedded OHDP sediments. Bioaccumulation that occurred from these sediments was put into perspective with bioaccumulation from sediments normally resuspended in the Bay by natural processes, and from a demonstrably contaminated sediment. Indigenous SF Bay organisms were exposed to either bedded or suspended sediment in replicate experimental units of the Flow-through Aquatic Toxicology Exposure System (FATES) at the WES. Sediments and tissues were analyzed for a suite of contaminants, including organotins, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides and DDE, and ten metals.

  4. Distribution and Normalization of Heavy Metal Concentrations in Mangrove and Lagoonal Sediments from Mazatlán Harbor (SE Gulf of California)

    NASA Astrophysics Data System (ADS)

    Soto-Jiménez, M. F.; Páez-Osuna, F.

    2001-09-01

    Concentrations of heavy metals, carbonates, organic carbon and granulometry were examined in sediments from 60 sites within Mazatlán Harbor and adjacent areas. Regional distribution had a strong (for Al, Fe, Li and Ni) and weak (for Cd, Co, Cr, Pb, V and Zn) seaward concentration gradient decreasing from the upper lagoon. The highest concentrations for most metals occurred in fine-grained sediments from Infiernillo Estuary, the upper lagoon and the industrial zone. In contrast, lower levels were usually found in the sandy sediments of the navigation channel, port entrance and an area associated with sewage outfall. Analysis of transects in mangrove and lagoonal sediments indicated that the amount of fine material and organic carbon increases towards the margins where mangrove sediments exist. While metal variations were not clearly observed in most of the metals examined; only Ni, V, Pb and Cu showed a slight tendency to increase towards the margins. Sometimes lagoonal sediments had redox and texture characteristics comparable to those from mangrove substrate, thus competing because of a similar capture capacity of metals. Metal data were normalized against Al and Li using a combination of normalization techniques (95% prediction intervals, regional anomalies and enrichment factor). It was found that Al and Li were good normalizers for most of the examined metals and they are important constituents of one or more of the major fine-grained heavy metal carrier(s) and adequately reflect the granulometric variability in the sediments of the study area.

  5. Influence of sediment cohesion on deltaic shoreline dynamics and bulk sediment retention: A laboratory study

    NASA Astrophysics Data System (ADS)

    Straub, Kyle M.; Li, Qi; Benson, W. Matthew

    2015-11-01

    While boundary and forcing conditions influence the average location of a shoreline in deltaic systems, internal morphodynamics can drive high-magnitude deviations from the long-term trend. Here we explore the role of sediment cohesion on these morphodynamics using physical experiments. Specifically, we explore the role of sediment cohesion on the scales of autogenic shoreline transgressions and regressions. Results indicate that sediment cohesion enhances the time and space scales associated with autogenic cycles of channel formation, elongation, and abandonment. In systems with high sediment cohesion, this cycle can drive shoreline transgressions that produce flooding surfaces in the resulting stratigraphy which could be confused with surfaces produced by increases in sea level rise or subsidence rates. Enhanced channelization resulting from sediment cohesion also increases the pumping of fine-grained sediment into the marine realm, where it can bypass the delta foreset, thus decreasing total delta sediment retention rate.

  6. Site-specific features influence sediment stability of intertidal flats

    NASA Astrophysics Data System (ADS)

    Defew, Emma C.; Tolhurst, Trevor J.; Paterson, David M.

    The factors that influence the sediment stability and the transport of estuarine mudflats are not yet fully understood but knowledge of them is essential in coastal engineering applications and pollution ecology studies. The suggestion that variation in predictive models of sediment stability might be due to site-specific characteristics is investigated using data from four estuarine mudflats (Eden Estuary, Scotland, the Biezelingsche Ham, Zandkreek, and Molenplaat mudflats in The Netherlands). These estuaries differ in their environmental conditions, macrofaunal species composition and local features (e.g. Enteromorpha mats, migratory biofilms). Stable and unstable sediments were compared, and mean chlorophyll-a concentrations and granulometry of the sediments were significantly different between the two groups. Step-wise multiple linear regressions were applied to the sediment stability data of all sites to establish the influences on erosion threshold of microphytobenthic biomass, water content, granulometry, organic carbon content and the abundance of dominant macrofaunal species. The stability of each site was influenced by different factors. Sediment stability of the Eden Estuary was affected by the Enteromorpha bloom; Biezelingsche Ham was influenced by the highly migratory nature of the diatom biofilms and the abundance of Corophium volutator; the polychaete worm Arenicola marina had a net negative effect on sediment stability of the Zandkreek; and the Molenplaat was influenced by microphytobenthic biomass. This research highlights the need for site-specific calibration of models and suggests that a universal proxy parameter for sediment stability is unlikely to be obtained.

  7. Water-level fluctuations influence sediment porewater ...

    EPA Pesticide Factsheets

    Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluctuations impact Hg cycling, particularly the formation of the more toxic and bioaccumulative methylmercury (MeHg). Total-Hg (THg), MeHg, stable isotope methylation rates and several ancillary parameters were measured in reservoir sediments (including some in porewater and overlying water) that are seasonally and permanently inundated. The results showed that sediment and porewater MeHg concentrations were over 3-times higher in areas experiencing water-level fluctuations compared to permanently inundated sediments. Analysis of the data suggest that the enhanced breakdown of organic matter in sediments experiencing water-level fluctuations has a two-fold effect on stimulating Hg methylation: 1) it increases the partitioning of inorganic Hg from the solid phase into the porewater phase (lower log Kd values) where it is more bioavailable for methylation; and 2) it increases dissolved organic carbon (DOC) in the porewater which can stimulate the microbial community that can methylate Hg. Sulfate concentrations and cycling were enhanced in the seasonally inundated sediments and may have also contributed to increased MeHg production. Overall, our results suggest that reservoir management a

  8. Water-level fluctuations influence sediment porewater ...

    EPA Pesticide Factsheets

    Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluctuations impact Hg cycling, particularly the formation of the more toxic and bioaccumulative methylmercury (MeHg). Total-Hg (THg), MeHg, stable isotope methylation rates and several ancillary parameters were measured in reservoir sediments (including some in porewater and overlying water) that are seasonally and permanently inundated. The results showed that sediment and porewater MeHg concentrations were over 3-times higher in areas experiencing water-level fluctuations compared to permanently inundated sediments. Analysis of the data suggest that the enhanced breakdown of organic matter in sediments experiencing water-level fluctuations has a two-fold effect on stimulating Hg methylation: 1) it increases the partitioning of inorganic Hg from the solid phase into the porewater phase (lower log Kd values) where it is more bioavailable for methylation; and 2) it increases dissolved organic carbon (DOC) in the porewater which can stimulate the microbial community that can methylate Hg. Sulfate concentrations and cycling were enhanced in the seasonally inundated sediments and may have also contributed to increased MeHg production. Overall, our results suggest that reservoir management a

  9. Sediment properties influencing the bioavailability of uranium to Chironomus dilutus larvae in spiked field sediments.

    PubMed

    Crawford, Sarah E; Liber, Karsten

    2016-04-01

    The partitioning of metals between dissolved and solid phases directly affects metal bioavailability to benthic invertebrates and is influenced by metal-binding properties of sediment phases. Little research has been done examining the effects of sediment properties on the bioavailability of uranium (U) to freshwater benthic invertebrates. In the present study, 18 field sediments with a wide range of properties (total organic carbon, fine fraction, cation exchange capacity, and iron content) were amended with the same concentrations of U to characterize the effects of these sediment properties on U bioavailability to freshwater midge, Chironomus dilutus. Bioaccumulation of U by C. dilutus larvae varied by over an order of magnitude when exposed to sediments spiked with 50 mg U kg(-1) d.w. (5-69 mg U kg(-1) d.w.) and 500 mg U kg(-1) d.w. (20-452 mg U kg(-1) d.w.), depending on the type of sediment. Variance in U bioaccumulation was best explained by differences in the cation exchange capacity, fine fraction (≤50 μm particle size), and Fe content of U-spiked sediment, with generated regression equations predicting observed bioaccumulation within a factor of two. The presented regression equations offer an easy-to-apply method for accounting for the influence of sediment properties on U bioavailability in freshwater sediment, with fine fraction being the single most practical variable. This research strongly supports that risk assessments and guidelines for U-contaminated sediments should not ignore the influence of sediment properties that can result in substantial differences in the bioaccumulation of U in benthic invertebrates.

  10. Nutrient budgets, marsh inundation under sea-level rise scenarios, and sediment chronologies for the Bass Harbor Marsh estuary at Acadia National Park

    USGS Publications Warehouse

    Huntington, Thomas G.; Culbertson, Charles W.; Fuller, Christopher C.; Glibert, Patricia; Sturtevant, Luke

    2014-01-01

    Eutrophication in the Bass Harbor Marsh estuary on Mount Desert Island, Maine, is an ongoing problem manifested by recurring annual blooms of green macroalgae species, principally Enteromorpha prolifera and Enteromorpha flexuosa, blooms that appear in the spring and summer. These blooms are unsightly and impair the otherwise natural beauty of this estuarine ecosystem. The macroalgae also threaten the integrity of the estuary and its inherent functions. The U.S. Geological Survey and Acadia National Park have collaborated for several years to better understand the factors related to this eutrophication problem with support from the U.S. Geological Survey and National Park Service Water Quality Assessment and Monitoring Program. The current study involved the collection of hydrologic and water-quality data necessary to investigate the relative contribution of nutrients from oceanic and terrestrial sources during summer 2011 and summer 2012. This report provides data on nutrient budgets for this estuary, sedimentation chronologies for the estuary and fringing marsh, and estuary bathymetry. The report also includes data, based on aerial photographs, on historical changes from 1944 to 2010 in estuary surface area and data, based on surface-elevation details, on changes in marsh area that may accompany sea-level rise. The LOADEST regression model was used to calculate nutrient loads into and out of the estuary during summer 2011 and summer 2012. During these summers, tidal inputs of ammonium to the estuary were more than seven times greater than the combined inputs in watershed runoff and precipitation. In 2011 tidal inputs of nitrate were about four times greater than watershed plus precipitation inputs, and in 2012 tidal inputs were only slightly larger than watershed plus precipitation inputs. In 2011, tidal inputs of total organic nitrogen were larger than watershed input by a factor of 1.6. By contrast, in 2012 inputs of total organic nitrogen in watershed runoff

  11. Investigations of the potential influence of environmental contaminants on the thymus and spleen of harbor porpoises (Phocoena phocoena).

    PubMed

    Beineke, Andreas; Siebert, Ursula; McLachlan, Michael; Bruhn, Regina; Thron, Kristina; Failing, Klaus; Müller, Gundi; Baumgärtner, Wolfgang

    2005-06-01

    Harbor porpoises from the German North and Baltic Seas exhibit a higher incidence of bacterial infections compared to whales from less polluted arctic waters. The potential adverse effect of environmental contaminants such as polychlorinated biphenyls (PCBs) and heavy metals on the immune system and the health status of marine mammals is still discussed controversially. The aim of the present study was to investigate the possible influence of PCB, polybrominated diphenyl ether (PBDE), toxaphene, (p,p'-dichlorodiphenyl)trichlorethane (DDT), and (p,p'-dichlorodiphenyl)dichlorethene (DDE) on the immune system of harbor porpoises. Lymphoid organs are influenced by a variety of factors, and therefore special emphasis was given to separating the confounding effect of age, health status, nutritional state, geographical location, and sex from the effect of contaminant levels upon thymus and spleen. Contaminant analysis and detailed pathological examinations were conducted on 61 by-caught and stranded whales from the North and Baltic Seas and Icelandic and Norwegian waters. Stranded harbor porpoises were more severely diseased than by-caught animals. Thymic atrophy and splenic depletion were significantly correlated to increased PCB and PBDE levels. However, lymphoid depletion was also associated with emaciation and an impaired health status. The present report supports the hypothesis of a contaminant-induced immunosuppression, possibly contributing to disease susceptibility in harbor porpoises. However, further studies are needed to determine if lymphoid depletion is primarily contaminant-induced or secondary to disease and emaciation in this cetacean species.

  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. Sensitivity of an indigenous amphipod (Corophium colo) to chemical contaminants in laboratory toxicity tests conducted with sediments from Sydney Harbor, Australia, and vicinity.

    PubMed

    McCready, Stephanie; Greely, Christopher R; Hyne, Ross V; Birch, Gavin F; Long, Edward R

    2005-10-01

    Laboratory survival tests were conducted with an indigenous infaunal amphipod, Corophium colo, on 103 sediment samples from Sydney Harbor (NSW, Australia) and vicinity, containing a wide range of chemicals and concentrations. The present study describes the sensitivity of C. colo to the sediments and compares the results to data for North American amphipods (Rhepoxynius abronius and Ampelisca abdita) previously used to establish and validate sediment-quality guidelines (SQGs). The incidence of toxicity increased with increasing contamination, as indicated by increasing numbers of SQGs exceeded and increasing mean SQG quotients. The incidence of highly toxic results (p < 0.05 and mean amphipod survival of < 80% that of controls) for highly contaminated samples was approximately half (28-40%) that of a large U.S. database (74%). The incidence of highly toxic responses for samples with intermediate levels of contamination also was lower in the present study (5-13%) compared to the results in large U.S. studies (approximately 30-50%). Corophium colo reburial tests showed greater sensitivity compared to survival tests, with a maximum incidence of statistically significant responses in moderately contaminated sediments of 70%. The present study showed that adult Corophium organisms are suitable for testing lethal responses in highly contaminated sediments (i.e., with mean effects range-median quotients of >1.5). Reburial results provide additional sensitivity.

  14. Environmental Conditions Outweigh Geographical Contiguity in Determining the Similarity of nifH-Harboring Microbial Communities in Sediments of Two Disconnected Marginal Seas

    PubMed Central

    Zhou, Haixia; Dang, Hongyue; Klotz, Martin G.

    2016-01-01

    Ecological evidence suggests that heterotrophic diazotrophs fueled by organic carbon respiration in sediments play an important role in marine nitrogen fixation. However, fundamental knowledge about the identities, abundance, diversity, biogeography, and controlling environmental factors of nitrogen-fixing communities in open ocean sediments is still elusive. Surprisingly, little is known also about nitrogen-fixing communities in sediments of the more research-accessible marginal seas. Here we report on an investigation of the environmental geochemistry and putative diazotrophic microbiota in the sediments of Bohai Sea, an eutrophic marginal sea of the western Pacific Ocean. Diverse and abundant nifH gene sequences were identified and sulfate-reducing bacteria (SRB) were found to be the dominant putative nitrogen-fixing microbes. Community statistical analyses suggested bottom water temperature, bottom water chlorophyll a content (or the covarying turbidity) and sediment porewater Eh (or the covarying pH) as the most significant environmental factors controlling the structure and spatial distribution of the putative diazotrophic communities, while sediment Hg content, sulfide content, and porewater SiO32−-Si content were identified as the key environmental factors correlated positively with the nifH gene abundance in Bohai Sea sediments. Comparative analyses between the Bohai Sea and the northern South China Sea (nSCS) identified a significant composition difference of the putative diazotrophic communities in sediments between the shallow-water (estuarine and nearshore) and deep-water (offshore and deep-sea) environments, and sediment porewater dissolved oxygen content, water depth and in situ temperature as the key environmental factors tentatively controlling the species composition, community structure, and spatial distribution of the marginal sea sediment nifH-harboring microbiota. This confirms the ecophysiological specialization and niche differentiation

  15. Numerical investigation of infragravity wave amplifications during harbor oscillations influenced by variable offshore topography

    NASA Astrophysics Data System (ADS)

    Gao, Junliang; Ji, Chunyan; Ma, Xiaojian; Liu, Yingyi; Gaidai, Oleg

    2017-09-01

    The infragravity (IG) period oscillations inside an elongated rectangular harbor near the offshore fringing reef induced by normal-incident bichromatic short wave groups are simulated using a fully nonlinear Boussinesq model, FUNWAVE 2.0. Based on an IG wave separation procedure, this article presents a systematical investigation on how the maximum IG period component amplitude, the bound and free IG waves, and their relative components inside the harbor change with respect to the plane reef-face slope and the incident short wave amplitude under the condition of the 2nd to the 5th modes. For the given harbor and the ranges of the reef-face slope and the incident short wave amplitude studied in this paper, it is shown that both the maximum IG period component amplitude and the free IG wave component amplitude inside the harbor fluctuate widely with the reef-face slope, and their changing trends with the reef-face slope are almost identical with each other, while the bound IG waves inside the harbor seem insensitive to it. Both the maximum IG period component amplitude and those of the bound and free IG standing waves inside the harbor change cubically with the incident short wave amplitude.

  16. Remediation of contaminated marine sediment using thin-layer capping with activated carbon--a field experiment in Trondheim harbor, Norway.

    PubMed

    Cornelissen, Gerard; Kruså, Marie Elmquist; Breedveld, Gijs D; Eek, Espen; Oen, Amy M P; Arp, Hans Peter H; Raymond, Caroline; Samuelsson, Göran; Hedman, Jenny E; Stokland, Øystein; Gunnarsson, Jonas S

    2011-07-15

    In situ amendment of contaminated sediments using activated carbon (AC) is a recent remediation technique, where the strong sorption of contaminants to added AC reduces their release from sediments and uptake into organisms. The current study describes a marine underwater field pilot study in Trondheim harbor, Norway, in which powdered AC alone or in combination with sand or clay was tested as a thin-layer capping material for polycyclic aromatic hydrocarbon (PAH)-contaminated sediment. Several novel elements were included, such as measuring PAH fluxes, no active mixing of AC into the sediment, and the testing of new manners of placing a thin AC cap on sediment, such as AC+clay and AC+sand combinations. Innovative chemical and biological monitoring methods were deployed to test capping effectiveness. In situ sediment-to-water PAH fluxes were measured using recently developed benthic flux chambers. Compared to the reference field, AC capping reduced fluxes by a factor of 2-10. Pore water PAH concentration profiles were measured in situ using a new passive sampler technique, and yielded a reduction factor of 2-3 compared to the reference field. The benthic macrofauna composition and biodiversity were affected by the AC amendments, AC + clay having a lower impact on the benthic taxa than AC-only or AC + sand. In addition, AC + clay gave the highest AC recoveries (60% vs 30% for AC-only and AC + sand) and strongest reductions in sediment-to-water PAH fluxes and porewater concentrations. Thus, application of an AC-clay mixture is recommended as the optimal choice of the currently tested thin-layer capping methods for PAHs, and more research on optimizing its implementation is needed.

  17. Cascade dams influence on sediment characteristics and phosphorus distribution.

    NASA Astrophysics Data System (ADS)

    Rapin, Anne; Mourier, Brice; Rabiet, Marion; Malgorzata, Grybos; Kestens, Tim; Deluchat, Veronique

    2017-04-01

    Massive river artificialisation by dam construction, responding to the steadily increasing human demand of water and electricity leads to several environmental consequences, including alteration of hydrological dynamic and sediment discontinuity. Important decreases of water flows and sediment transport downstream impact phosphorus (P) flux to the ocean and its cycle, due to P sediment storage in dam reservoir. Moreover, the release of P from sediments may enhance eutrophication processes in dam reservoir. Our study focused on the influence of cascade dams on physical and chemical characteristics of sediments and particularly on P sedimentary speciation along river continuum. Considering these results, the potential of P release from dam reservoir sediments was appraised and compared to un-impacted river parts. In addition, key parameters controlling P release at sediment/water interface were evaluated. Champsanglard, Chézelles and Age are three consecutive hydroelectric reservoirs on Creuse River (France; respective surfaces area of 55 ha, 23 ha, 38 ha and approximative height of 20 m each) subjected to seasonal cyanobacterial blooms. Surface sediments (17 samples) were collected in dams and free-flow river sections (on a stretch of 17 km); chemical composition (Fe, Al, Ca, Mn and P), organic matter (OM) content, particle size distribution and P fractionation were analysed. An abrupt change in sediment granulometry from a coarse-medium sand to silt texture going through free-flow river to dam reservoirs was observed. The same assessment was made in regard to OM content (from 3 ± 3% in river parts to 18 ± 3% in dams) and total P (0.27 ± 0.11 mgP/g DW in river parts to 1.8 ± 0.3 mgP/gDW in dams). P enrichment in sediment from dam reservoir is due to the retention of fine size particles. Relation between total P content and sediment grain size within each dam reservoir highlighted the role of slowdown river flow occurring in dams. In Champsanglard reservoir

  18. Influence of the Pearl River estuary and vertical mixing in Victoria Harbor on water quality in relation to eutrophication impacts in Hong Kong waters.

    PubMed

    Yin, Kedong; Harrison, Paul J

    2007-06-01

    This study presents water quality parameters such as nutrients, phytoplankton biomass and dissolved oxygen based on 11 years of water quality data in Victoria Harbor and examined how the Pearl River estuary discharge in summer and year round sewage discharge influenced these parameters. Nutrients in Victoria Harbor were strongly influenced by both the Pearl River and sewage effluent, as indicated by the high NO(3) inputs from the Pearl River in summer and higher NH(4) and PO(4) in Victoria Harbor than both its sides. N:P ratios were low in the dry season, but increased to >16:1 in the wet season, suggesting that P is potentially the most limiting nutrient in this area during the critical period in the summer. Although there were generally high nutrients, the phytoplankton biomass was not as high as one would expect in Victoria Harbor. In fact, there were high concentrations of chl near the bottom well below the photic zone. Salinity near the bottom was lower in Victoria Harbor than at the two entrances to Victoria Harbor, suggesting strong vertical mixing within Victoria Harbor. Therefore, strong vertical mixing and horizontal advection appear to play an important role in significantly reducing eutrophication impacts in Victoria Harbor. Consequently, dissolved oxygen near the bottom was low in summer, but only occasionally dipped to 2 mgL(-1) despite the high organic loading from sewage effluent.

  19. Temporal characterization of bacterial communities in a phytoremediation pilot plant aimed at decontaminating polluted sediments dredged from Leghorn harbor, Italy.

    PubMed

    Chiellini, Carolina; Iannelli, Renato; Petroni, Giulio

    2013-09-25

    The AGRIPORT project (Agricultural Reuse of Polluted Dredged Sediments, Eco-innovation EU Project n. ECO/08/239065) aims at developing a new technology for the treatment of polluted sediments dredged from the seabed of commercial ports through phytoremediation processes. Through plant activities and microorganism metabolisms, it is possible to recover dredged saline sediments by decontaminating them until an artificially prepared soil that is reusable in the terrestrial environment is obtained. This is an important advantage from the environmental point of view, and allows to partially solve one of the main problems of most commercial ports, that is the accumulation, storage and disposal of polluted dredged sediments. Considering that bacteria provide a significant contribution to phytoremediation process. Aim of the present study is the monitoring of temporal variation of microbial communities developing in an experimental phytoremediation plant during the decontamination process. The treatment plant consists of a sealed 80 m(3) basin that is filled with a mixture of dredged sediments (75%) and natural soil (25%). It was planted with three plant species, and has been properly cultivated and fertilized for two years. Terminal Restriction Fragment Length Polymorphism (T-RFLP) on 16S rRNA gene was used to study the composition of bacterial communities at different times and points in the basin. Cluster Analysis (CA) and Non Metric Multidimensional Scaling (NMDS) multivariate statistics were applied for data interpretation. At the onset, the bacterial communities were heterogeneous and discrete, reflecting those inherited from the sediment-soil mixture, from compost and from plant's rhizospheres. The communities' composition rapidly changed to become stabilized after one year. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Influence of graphite flake addition to sediment on electrogenesis in a sediment-type fuel cell.

    PubMed

    Lenin Babu, M; Venkata Mohan, S

    2012-04-01

    Graphite flakes at levels of 5%, 15%, 20% and 40% (weight per sediment volume) were added to lake bed sediment and electrogenesis in a sediment-type fuel cell was evaluated. Addition of graphite flakes by 20% to the sediment showed higher electrogenic activity of the fuel cell (578mV; 0.37mW) compared to control (304mV; 0.26mW). Further increment in the graphite loading showed a negative influence on the fuel cell behavior. A higher energy and capacitance were recorded with 20% addition of graphite flakes compared to the control. Increase in the exchange current density and decrease in the Tafel slope and electron transfer coefficient was observed with addition of graphite flakes. Apparent surface coverage analysis also supported the higher performance upon addition of 20% graphite flakes. The relative increase in the conductivity of bed due to addition of graphite flakes might be the reason for observed electrogenic activity. Marginal variation in the substrate utilization ( [Formula: see text] 50-55%) was observed with the addition of graphite flakes. By adding an optimum level of graphite flakes to sediment influences the fuel cell performance.

  1. Growth and mortality of coral transplants (Pocillopora damicornis) along a range of sediment influence in Maui, Hawai'i

    USGS Publications Warehouse

    Piniak, G.A.; Brown, E.K.

    2008-01-01

    Fragments of the lace coral Pocillopora damicornis (Linnaeus, 1758) were transplanted to four sites on the south-central coast of Maui, Hawai'i, to examine coral growth over a range of expected sediment influence. Corals remained in situ for 11 months and were recovered seasonally for growth measurements using the buoyant weight technique. Average sediment trap accumulation rates ranged from 11 to 490 mg cm-2 day-1 and were greater at the wave-exposed reef site than at the protected harbor sites. Coral growth was highest at the donor site and was higher in the summer than in the winter. A stepwise linear regression found significant effects of sediment trap accumulation and light on growth rates, but the partial correlation coefficients suggest that these factors may be only secondary controls on growth. This study did not show a clear link between coral growth and sediment load. This result may be due, in part, to covariation of sediment load with wave exposure and the inability of trap accumulation rates to integrate all sediment effects (e.g., turbidity) that can affect coral growth. ?? 2008 by University of Hawai'i Press. All rights reserved.

  2. MAINTAINING ACCESS TO AMERICA'S INTERMODAL PORTS/TECHNOLOGIES FOR DECONTAMINATION OF DREDGED SEDIMENT: NEW YORK/NEW JERSEY HARBOR

    SciTech Connect

    STERN,E.A.; JONES,K.; DONATO,K.; PAULING,J.D.; SONTAG,J.G.; CLESCERI,N.L.; MENSINGER,M.C.; WILDE,C.L.

    1998-05-01

    One of the greatest drivers for maintaining access to America's Intermodal ports and related infrastructure redevelopment efforts over the next several years will be the control and treatment of contaminated sediments dredged from the nation's waterways. More than 306 million cubic meters (m{sup 3}) (400 million cubic yards [cy]) of sediments are dredged annually from US waterways, and each year close to 46 million m{sup 3} (60 million cy) of this material is disposed of in the ocean (EPA 842-F-96-003). The need to protect the environment against undesirable effects from sediment dredging and disposal practices is gaining increased attention from the public and governmental agencies. Meeting this need is a challenging task not only from the standpoint of solving formidable scientific and engineering problems, but also, and more importantly, from the need to implement complex collaborations among the many different parties concerned with the problem. Some 40 years ago, C.P. Snow pointed out the problems involved in communicating between the two cultures of the sciences and the humanities (Snow, 1993). Today, it is necessary to extend Snow's concept to a multicultural realm with groups that include governmental, industrial, environmental, academic, and the general public communicating in different languages based on widely different fundamental assumptions. The handling of contaminated sediments in the Port of New York/New Jersey (Port) exemplifies this problem. This paper describes a multicultural team that has formed as the result of a Congressional mandate for the development of procedures suitable for the decontamination of sediments in the Port under the Water Resources Development Act (WRDA) of 1992 (Section 405C) and 1996 (Section 226).

  3. Factors influencing organic carbon preservation in marine sediments

    NASA Technical Reports Server (NTRS)

    Canfield, D. E.

    1994-01-01

    The organic matter that escapes decomposition is buried and preserved in marine sediments, with much debate as to whether the amount depends on bottom-water O2 concentration. One group argues that decomposition is more efficient with O2, and hence, organic carbon will be preferentially oxidized in its presence, and preserved in its absence. Another group argues that the kinetics of organic matter decomposition are similar in the presence and absence of O2, and there should be no influence of O2 on preservation. A compilation of carbon preservation shows that both groups are right, depending on the circumstances of deposition. At high rates of deposition, such as near continental margins, little difference in preservation is found with varying bottom-water O2. It is important that most carbon in these sediments decomposes by anaerobic pathways regardless of bottom-water O2. Hence, little influence of bottom-water O2 on preservation would, in fact, be expected. As sedimentation rate drops, sediments deposited under oxygenated bottom water become progressively more aerobic, while euxinic sediments remain anaerobic. Under these circumstances, the relative efficiencies of aerobic and anaerobic decomposition could affect preservation. Indeed, enhanced preservation is observed in low-O2 and euxinic environments. To explore in detail the factors contributing to this enhanced carbon preservation, aspects of the biochemistries of the aerobic and anaerobic process are reviewed. Other potential influences on preservation are also explored. Finally, a new model for organic carbon decomposition, the "pseudo-G" model, is developed. This model couples the degradation of refractory organic matter to the overall metabolic activity of the sediment, and has consequences for carbon preservation due to the mixing together of labile and refractory organic matter by bioturbation.

  4. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues.

    PubMed

    Baldi, Franco; Gallo, Michele; Marchetto, Davide; Faleri, Claudia; Maida, Isabel; Fani, Renato

    2013-08-01

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5mgl(-1) HgCl2 and incubated at 30°C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Heavy metals in Mercenaria mercenaria and sediments from the New Bedford Harbor region of Buzzard's Bay, Massachusetts

    SciTech Connect

    Genest, P.E.; Hatch, W.I.

    1981-01-01

    M. mercenaria and sediments from the New Bedford region were analyzed for cadmium, copper, iron, lead, and zinc to investigate some of the relationships between environmental and organismal levels. It appears that at present there is no major contamination of clams or sediments in the areas studied. However, since levels of some metals approached the permissible limits at times, it would obviously be beneficial if all sources of pollution to the area could be identified and regulated. It is suggested that harvesting of clams could be managed seasonally so that tissue contaminants are at their periodic minima. For these metals late summer, fall, and winter appear to be favorable times. It is also suggested that clams harvested in the vicinity of recently dredged areas be monitored for heavy metal levels. The need for a continuous monitoring program for heavy metals and other toxic substances for New Bedford and surrounding areas to insure public safety is recommended.

  6. Characterization of harbor sediments from the English Channel: assessment of heavy metal enrichment, biological effect and mobility.

    PubMed

    Hamdoun, H; Van-Veen, E; Basset, B; Lemoine, M; Coggan, J; Leleyter, L; Baraud, F

    2015-01-15

    For a full assessment of the environmental risk posed by dredged sediments not only the anthropogenic enrichment of contaminants, but also their mobility and biological impact should be considered. This study reports on the enrichment factor (EF), mobility, and Adverse Effect Index (AEI) of metals and metalloids in nine dredged sediments. Significant enrichment of As, Cd, Pb and Zn with respect to background values is detected, and calculated AEI values for these elements suggest that it is possible that a corresponding biological effect may be observed. Correlation coefficients also reveal a link between mobility in HCl and enrichment for Cd, Cr, Ni, Pb and Zn, however As and Cu do not display such a link, possibly suggesting that the source of contamination for these elements is less recent. Mobility and enrichment are two parameters which are often studied separately; however this paper shows that in some cases strong correlations occur.

  7. Demonstration of In Situ Treatment with Reactive Amendments for Contaminated Sediments in Active DoD Harbors

    DTIC Science & Technology

    2017-06-30

    6: Demonstrate Uniform Deep Water Placement to Target Footprint and Physical Stability Over Time...of contaminants into the tissues of benthic invertebrates, and subsequently the food web . The sorbent material, AquaGate®+PAC (referred to here as...enable deep water placement of the material on the sediment surface. The AquaGate, which is denser than water, sinks rapidly through the water column

  8. Marine Oxygen-Deficient Zones Harbor Depauperate Denitrifying Communities Compared to Novel Genetic Diversity in Coastal Sediments.

    PubMed

    Bowen, Jennifer L; Weisman, David; Yasuda, Michie; Jayakumar, Amal; Morrison, Hilary G; Ward, Bess B

    2015-08-01

    Denitrification is a critically important biogeochemical pathway that removes fixed nitrogen from ecosystems and thus ultimately controls the rate of primary production in nitrogen-limited systems. We examined the community structure of bacteria containing the nirS gene, a signature gene in the denitrification pathway, from estuarine and salt marsh sediments and from the water column of two of the world's largest marine oxygen-deficient zones (ODZs). We generated over 125,000 nirS gene sequences, revealing a large degree of genetic diversity including 1,815 unique taxa, the vast majority of which formed clades that contain no cultured representatives. These results underscore how little we know about the genetic diversity of metabolisms underlying this critical biogeochemical pathway. Marine sediments yielded 1,776 unique taxa when clustered at 95 % sequence identity, and there was no single nirS denitrifier that was a competitive dominant; different samples had different highly abundant taxa. By contrast, there were only 39 unique taxa identified in samples from the two ODZs, and 99 % of the sequences belonged to 5 or fewer taxa. The ODZ samples were often dominated by nirS sequences that shared a 92 % sequence identity to a nirS found in the anaerobic ammonium-oxidizing (anammox) genus Scalindua. This sequence was abundant in both ODZs, accounting for 38 and 59 % of all sequences, but it was virtually absent in marine sediments. Our data indicate that ODZs are remarkably depauperate in nirS genes compared to the remarkable genetic richness found in coastal sediments.

  9. MAINTAINING ACCESS TO AMERICA'S INTERMODAL PORTS/TECHNOLOGIES FOR DECONTAMINATION OF DREDGED SEDIMENT: NEW YORK/NEW JERSEY HARBOR.

    SciTech Connect

    STERN,E.A.; JONES,K.; DONATO,K.; PAULING,J.D.; SONTAG,J.G.; CLESCERI,N.L.; MENSINGER,M.C.; WILDE,C.L.

    1998-05-01

    One of the greatest drivers for maintaining access to America's Intermodal ports and related infrastructure redevelopment efforts over the next several years will be the control and treatment of contaminated sediments dredged from our nation's waterways. More than 306 million cubic meters (m{sup 3}) (400 million cubic yards [cy]) of sediments are dredged annually from U.S. waterways, and each year close to 46 million m{sup 3} (60 million cy) of this material is disposed of in the ocean (EPA 842-F-96-003). The need to protect our environment against undesirable effects from sediment dredging and disposal practices is gaining increased attention from the public and governmental agencies. Meeting this need is a challenging task not only from the standpoint of solving formidable scientific and engineering problems, but also, and more importantly, from the need to implement complex collaborations among the many different parties concerned with the problem. Some 40 years ago, C.P. Snow pointed out the problems involved in communicating between the two cultures of the sciences and the humanities (Snow, 1993). Today, it is necessary to extend Snow's concept to a multicultural realm with groups that include governmental, industrial, environmental, academic, and the general public communicating in different languages based on widely different fundamental assumptions.

  10. Biodegradation of petroleum hydrocarbons in estuarine sediments: metal influence.

    PubMed

    Almeida, Raquel; Mucha, Ana P; Teixeira, Catarina; Bordalo, Adriano A; Almeida, C Marisa R

    2013-02-01

    In this work, the potential effect of metals, such as Cd, Cu and Pb, on the biodegradation of petroleum hydrocarbons in estuarine sediments was investigated under laboratory conditions. Sandy and muddy non-vegetated sediments were collected in the Lima River estuary (NW Portugal) and spiked with crude oil and each of the metals. Spiked sediments were left in the dark under constant shaking for 15 days, after which crude oil biodegradation was evaluated. To estimate microbial abundance, total cell counts were obtained by DAPI staining and microbial community structure was characterized by ARISA. Culturable hydrocarbon degraders were determined using a modified most probable number protocol. Total petroleum hydrocarbons concentrations were analysed by Fourier Transform Infrared Spectroscopy after their extraction by sonication, and metal contents were determined by atomic absorption spectrometry. The results obtained showed that microbial communities had the potential to degrade petroleum hydrocarbons, with a maximum of 32 % degradation obtained for sandy sediments. Both crude oil and metals changed the microbial community structure, being the higher effect observed for Cu. Also, among the studied metals, only Cu displayed measurable deleterious effect on the hydrocarbons degradation process, as shown by a decrease in the hydrocarbon degrading microorganisms abundance and in the hydrocarbon degradation rates. Both degradation potential and metal influence varied with sediment characteristics probably due to differences in contaminant bioavailability, a feature that should be taken into account in developing bioremediation strategies for co-contaminated estuarine sites.

  11. Do benthic diatoms influence erosion thresholds of coastal subtidal sediments?

    NASA Astrophysics Data System (ADS)

    Ziervogel, Kai; Forster, Stefan

    2006-01-01

    This study reports diatom cell abundance, concentrations of water-soluble and water-insoluble carbohydrates, and concentrations of chlorophyll—a equivalents as indicators of microbial exudates and biomass in the uppermost sediment layer of two coastal sites (19 m water depth: fine sand; 25 m water depth: mud) in Mecklenburg Bight, south-western Baltic Sea. Correlation analysis with experimentally determined erosion thresholds measured in five different periods of a year showed that the sediment water content and the content of water-soluble carbohydrates may indicate erosion thresholds for both sediment types. Erosion thresholds were significantly negatively correlated with sediment water content at the mud site. At both sites, colloidal carbohydrates, as indicators for diatom EPS, showed significantly negative correlations with sediment water content and no correlation with diatom biomass. Therefore, following current interpretation, we argue that micro-biostabilsation effects of benthic microalgae play a minor role in the investigation area. Light is likely to be insufficient for phototrophic growth on the seafloor of the investigated sites most of the year, as indicated by in situ measurements and calculated values of photosynthetically active radiation. We consider lateral transport of benthic diatoms from shallower to deeper areas of Mecklenburg Bight and subsequent to be the mechanism influencing diatom abundance. Exhaustive biofilms are absent at these depths and mass erosion is not likely to be affected by benthic diatoms.

  12. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    SciTech Connect

    Baldi, Franco; Gallo, Michele; Marchetto, Davide; Faleri, Claudia; Maida, Isabel; Fani, Renato

    2013-08-15

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l{sup −1} HgCl{sub 2} and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified

  13. Anthropogenic Influences on Estuarine Sedimentation in Salem Sound, MA

    NASA Astrophysics Data System (ADS)

    Kristiansen, E. R.; Hubeny, J. B.; Zhu, J.; Olsen, C. R.; Warren, B.

    2010-12-01

    The Salem Sound watershed (MA) historically has been a region of significant industrial activity. Two specific point sources for pollution in the region are the South Essex Sewerage District (SESD) wastewater treatment facility, and the Salem Harbor Power Station, a coal-burning power plant. This study tests the hypothesis that human impact on Salem Sound is preserved in the sediment record. A sediment core was taken near the location of the SESD outfall. This core was analyzed for content of organic matter via loss on ignition (LOI), as well as magnetic susceptibility. An age model was constructed using 137Cs and 210Pb. Below 31 cm (mid-nineteenth century), the core contains mean background values of 2.7% LOI and values increase above this depth. At 21cm, a rapid increase in organic matter concentration from 6.6% to 11.8% is observed. This depth corresponds to ~1905 which is contemporaneous with construction of the outfall pipe discharging raw wastewater. At a depth of 7 cm (mid 1970s), LOI values decrease from 11.7% to 9.3%. This shift is likely attributed to SESD beginning primary treatment in 1977. LOI values continue to drop at 2cm (late 1990s), from 7.8% to 6.3%, and remain at 6.1% to the modern surface, likely a result of SESD upgrading to secondary treatment in 1998. Magnetic susceptibility also shows variability down core that is likely attributed to human impact. At a depth of approximately 20cm susceptibility values start increasing from 4.2 SI units until they reach a peak at 15cm (8.8 SI units). This increase can be attributed to the industrial revolution and increased industrial activity in the area. A decrease in susceptibility is observed at 15cm to 11cm (5.6 SI units) that may be attributed to the Great Depression and less fossil fuels being burned due to the economic situation. At approximately 10cm and 8.0 SI units, an increasing trend is first observed. This trend continues up to the modern surface where it eventually reaches 19.9 SI units. This

  14. Methane Seep in Shallow-Water Permeable Sediment Harbors High Diversity of Anaerobic Methanotrophic Communities, Elba, Italy

    PubMed Central

    Ruff, S. Emil; Kuhfuss, Hanna; Wegener, Gunter; Lott, Christian; Ramette, Alban; Wiedling, Johanna; Knittel, Katrin; Weber, Miriam

    2016-01-01

    The anaerobic oxidation of methane (AOM) is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB), and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic carbon depleted permeable sands off the Island of Elba (Italy). We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g-1 day-1 indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20–50 cm below seafloor) as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3, and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise distinct

  15. Methane Seep in Shallow-Water Permeable Sediment Harbors High Diversity of Anaerobic Methanotrophic Communities, Elba, Italy.

    PubMed

    Ruff, S Emil; Kuhfuss, Hanna; Wegener, Gunter; Lott, Christian; Ramette, Alban; Wiedling, Johanna; Knittel, Katrin; Weber, Miriam

    2016-01-01

    The anaerobic oxidation of methane (AOM) is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB), and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic carbon depleted permeable sands off the Island of Elba (Italy). We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g(-1) day(-1) indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20-50 cm below seafloor) as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3, and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise distinct

  16. Influence of Iron Redox Transformations on Plutonium Sorption to Sediments

    SciTech Connect

    Hixon, Amy E.; Hu, Yung-Jin; Kaplan, Daniel I.; Kukkadapu, Ravi K.; Nitsche, Heino; Qafoku, Odeta; Powell, Brian A.

    2010-10-01

    Plutonium subsurface mobility is primarily controlled by its oxidation state, which in turn is loosely coupled to the oxidation state of iron in the system. Experiments were conducted to examine the effect of sediment iron mineral composition and oxidation state on plutonium sorption and oxidation state. A pH 6.3 vadose zone sediment containing iron oxides and iron-containing phyllosilicates was treated with various complexants (ammonium oxalate) and reductants (dithionite-citrate-bicarbonate) to selectively leach and/or reduce iron oxide and phyllosilicate phases. Mössbauer spectroscopy was used to identify initial iron mineral composition of the sediment and monitor dissolution and reduction of iron oxides. Sorption of Pu(V) was monitored over one week for each of six treated sediment fractions. Plutonium oxidation state speciation in the aqueous and solid phases was monitored using solvent extraction, coprecipitation, and XANES. Mössbauer spectroscopy showed that the sediment contained 25-30% hematite, 60-65% Al-goethite, and <10%Fe(III) in phyllosilicate; there was no detectable Fe(II). Upon reduction with a strong chemical reductant (dithionite-citrate buffer, DCB), much of the hematite and goethite disappeared and the Fe in the phyllosilicate reduced to Fe(II). The rate of sorption was found to correlate with the 1 fraction of Fe(II) remaining within each treated sediment phase. Pu(V) was the only oxidation state measured in the aqueous phase, irrespective of treatment, whereas Pu(IV) and much smaller amounts of Pu(V) and Pu(VI) were measured in the solid phase. Surface-mediated reduction of Pu(V) to Pu(IV) occurred in treated and untreated sediment samples; Pu(V) remained on untreated sediment surface for two days before reducing to Pu(IV). Similar to the sorption kinetics, the reduction rate was correlated with sediment Fe(II) concentration. The correlation between Fe(II) concentrations and Pu(V) reduction demonstrates the potential impact of changing

  17. Contaminated Sediment

    EPA Pesticide Factsheets

    Contaminated sediments are a significant problem in the Great Lakes basin. Persistent high concentrations of contaminants in the bottom sediments of rivers and harbors pose risks to aquatic organisms, wildlife, and humans.

  18. Hyporheic zone as a bioreactor: sediment heterogeneity influencing biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Perujo, Nuria; Romani, Anna M.; Sanchez-Vila, Xavier

    2017-04-01

    Mediterranean fluvial systems are characterized by frequent periods of low flow or even drought. During low flow periods, water from wastewater treatment plants (WWTPs) is proportionally large in fluvial systems. River water might be vertically transported through the hyporheic zone, and then porous medium acts as a complementary treatment system since, as water infiltrates, a suite of biogeochemical processes occurs. Subsurface sediment heterogeneity plays an important role since it influences the interstitial fluxes of the medium and drives biomass growing, determining biogeochemical reactions. In this study, WWTP water was continuously infiltrated for 3 months through two porous medium tanks: one consisting of 40 cm of fine sediment (homogeneous); and another comprised of two layers of different grain size sediments (heterogeneous), 20 cm of coarse sediment in the upper part and 20 cm of fine one in the bottom. Several hydrological, physicochemical and biological parameters were measured periodically (weekly at the start of the experiment and biweekly at the end). Analysed parameters include dissolved nitrogen, phosphorus, organic carbon, and oxygen all measured at the surface, and at 5, 20 and 40 cm depth. Variations in hydraulic conductivity with time were evaluated. Sediment samples were also analysed at three depths (surface, 20 and 40 cm) to determine bacterial density, chlorophyll content, extracellular polymeric substances, and biofilm function (extracellular enzyme activities and carbon substrate utilization profiles). Preliminary results suggest hydraulic conductivity to be the main driver of the differences in the biogeochemical processes occurring in the subsurface. At the heterogeneous tank, a low nutrient reduction throughout the whole medium is measured. In this medium, high hydraulic conductivity allows for a large amount of infiltrating water, but with a small residence time. Since some biological processes are largely time-dependent, small water

  19. Volcanic influences: International working group on volcanogenic sediments

    NASA Astrophysics Data System (ADS)

    A conclusion of the Geological Society of America Penrose Conference on Volcanic Influences on Terrestrial Sedimentation (August 28 to September 2, 1988) was that establishment of an informal working group would enhance our understanding of volcanogenic sedimentation. To establish the group, an ad hoc steering committee was formed at the conference and consists of W. J. Fritz (Georgia State University), R. S. Hildebrand (Geological Survey of Canada), R. Iverson (U.S. Geological Survey), P. Kokelaar (Chairman, University of Liverpool), T. C. Pierson (USGS), and G. A. Smith (University of New Mexico). The working group is open to researchers of any nation interested in the study of secondary transport and deposition of volcaniclastic materials in subaerial or subaqueous environments (e.g., transport, deposition, nomenclature, volcanic history, experiment, theory, hazard).

  20. Influence of land use configurations on river sediment pollution.

    PubMed

    Liu, An; Duodu, Godfred O; Goonetilleke, Ashantha; Ayoko, Godwin A

    2017-10-01

    Land use is an influential factor in river sediment pollution. However, land use type alone is found to be inadequate to explain pollutant contributions to the aquatic environment since configurations within the same land use type such as land cover and development layout could also exert an important influence. Consequently, this paper discusses a research study, which consisted of an in-depth investigation into the relationship between land use type and river sediment pollution by introducing robust parameters that represent configurations within the primary land use types. Urban water pollutants, namely, nutrients, total carbon, polycyclic aromatic hydrocarbons and metals were investigated in the study. The outcomes show that higher patch density and more diverse land use development forms contribute relatively greater pollutant loads to receiving waters and consequently leading to higher sediment pollution. The study outcomes are expected to contribute essential knowledge for creating robust management strategies to minimise waterway pollution and thereby protect the health of aquatic ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Analysis of sediments and soils for chemical contamination for the design of US Navy homeport facility at East Waterway of Everett Harbor, Washington. Final report. [Macoma inquinata; Mytilus edulis

    SciTech Connect

    Anderson, J.W.; Crecelius, E.A.

    1985-03-01

    Contaminated sediments in the East Waterway of Everett Harbor, Washington, are extremely localized; they consist of a layer of organically-rich, fine sediments overlying a relatively cleaner, more sandy native material. The contaminated layer varies in thickness throughout the waterway from as much as 2 meters to only a few centimeters. Generally, the layer is thicker and more contaminated at the head of the waterway (northern end) and becomes thinner and less contaminated as one proceeds southerly out of the waterway and into Port Gardner. These sediments contain elevated levels of heavy metals and polynuclear aromatic hydrocarbons (PAH) and scattered concentrations of polychlorinated biphenyls (PCB). Approximately 500,000 cubic yards of material exhibit elevated chemical contamination compared to Puget Sound background levels. The contaminated sediments in this waterway require biological testing before decisions can be made regarding the acceptability of unconfined disposal.

  2. Influence of flocculation on sediment deposition process at the Three Gorges Reservoir.

    PubMed

    Wang, Dangwei; Liu, Xiaofang; Ji, Zuwen; Dong, Zhandi; Hu, Haihua

    2016-01-01

    By comparing the original particle gradation of sediment from the Three Gorges Reservoir with the single particle gradation, the differences in these two particle gradations showed that there is sediment flocculation in the Three Gorges Reservoir, which can accelerate the sediment deposition rate in the reservoir. In order to determine the influence of flocculation on the sediment settling velocity, sediment was collected at the Three Gorges Reservoir, and the indoor quiescent settling experiment was performed to study the mechanism of sediment flocculation. The experimental results showed that sediments aggregated from single particles into floccules in the settling processes. The single particles smaller than 0.022 mm will participate in the formation of floccules, which accounts for 83% of the total amount of sediment in the Three Gorges Reservoir. Moreover, the degree of sediment flocculation and the increase in sediment settling velocity were directly proportional to the sediment concentration. Taking the average particle size and the median particle size as the representative particle size, respectively, the maximum flocculation factors were calculated to be 3.4 and 5.0. Due to the sediment flocculation, the volume of sediment deposition will increase by 66% when the mass settling flux factor of total sediment had a maximum value of 1.66, suggesting that flocculation has a significant influence on the sediment deposition rate in the Three Gorges Reservoir.

  3. Evaluation of Sediment Agitation and Mixing into the Surrounding WaterColumn from Capping Activities at the Wyckoff/Eagle Harbor Superfund Site

    EPA Science Inventory

    Capping is a common remediation technology for the containment of contaminated sediments. While capping is a common remediation technology for contaminated sediments, little information exists on the potential release of contaminated sediments during and after the capping operati...

  4. Evaluation of Sediment Agitation and Mixing into the Surrounding WaterColumn from Capping Activities at the Wyckoff/Eagle Harbor Superfund Site

    EPA Science Inventory

    Capping is a common remediation technology for the containment of contaminated sediments. While capping is a common remediation technology for contaminated sediments, little information exists on the potential release of contaminated sediments during and after the capping operati...

  5. Decrease in Harbor Maintenance Dredging through the Use of Pile Dikes and Related Structures Together with an Analysis of Estuarine Sedimentation Problems

    DTIC Science & Technology

    1976-06-30

    Mississippi River" (Simmons and Rhodes, 1965), "Plans for Reduction of Shoaling in Brunswick Harbor and Jekyll Creek, Georgia" (Hermann and Tallant...2601. Herrmann, F. A., and Tallant, I. C., 1972, Plans for Reduction of Shoaling in Brunswick Harbor and Jekyll Creek Georgia. Tech. Report H-72-5 U

  6. Wind influence on the course of sedimentation processes of the laminated lacustrine sediments of Lake Czechowskie

    NASA Astrophysics Data System (ADS)

    Wiśniewska, Daria; Kramkowski, Mateusz; Tyszkowski, Sebastian

    2016-04-01

    The studies of the laminated lacustrine sediments play a very important role in the analysis of climate change. They provide valuable information related to the response of the ecosystem to changes in the environment. The condition for the development of the annual lamination is calm sedimentation, which can be compromised by the movement of water caused by waving. The depth to which this movement affects depends on the shape of the lake basin as well as the velocity and direction of the wind. During the study of sedimentary processes of laminated deposits in Lake Czechowskie (Tuchola Forest, North Poland, 53°52'N, 18°14' E, 108 m asl), the following question arose: How strong was the influence of the wind on the processes of lacustrine sedimentation? The key in getting the answers was the use of GIS techniques. Lake Czechowskie has an area of 76.6 hectares; it has two deeps separated by a threshold: a deeper one of 33 m (maximum depth of the basin) in the central-eastern part, and a shallower of 13 m in the western part. The speed of movement of water that is able to move sediment from the bottom of the lake, called the orbital wave velocity, is the basis for the designation of areas where re-suspension takes place. To calculate the wave parameters, the process of mixing, as well as the designation of re-suspension zones, the tool-script Wave Model (Rohweder et al. 2008) in the program ArsGIS 10.1 was used. The input data were wind direction and velocity from the meteorological station of Wirty about 15 km away, bathymetric data from acoustic profiling, and the Maximum Orbital Wave Velocity. The elements taken into account include maximum wind velocity of the multi-year 1996-2013, with particular emphasis on hurricanes Ksawery (December 2013) and Yoda (November 2011), during which wind velocity exceeded 120 km/h. In addition, maximum wind velocity ever recorded in the Polish Lowlands was considered. On the basis of the modelling, the authors delimited the areas

  7. [Pearl Harbor.

    ERIC Educational Resources Information Center

    Johnson, Jennifer, Ed.

    1992-01-01

    This issue of "Loblolly Magazine" was written in observance of the 50th anniversary of the U.S. entrance into World War II. The publication features interviews conducted by East Texas high school students with Clarence Otterman, one of the few survivors of the crew of the USS Arizona, which was bombed during the attack on Pearl Harbor,…

  8. Influence of sediment chemistry and sediment toxicity on macroinvertebrate communities across 99 wadable streams of the Midwestern USA.

    PubMed

    Moran, Patrick W; Nowell, Lisa H; Kemble, Nile E; Mahler, Barbara J; Waite, Ian R; Van Metre, Peter C

    2017-12-01

    Simultaneous assessment of sediment chemistry, sediment toxicity, and macroinvertebrate communities can provide multiple lines of evidence when investigating relations between sediment contaminants and ecological degradation. These three measures were evaluated at 99 wadable stream sites across 11 states in the Midwestern United States during the summer of 2013 to assess sediment pollution across a large agricultural landscape. This evaluation considers an extensive suite of sediment chemistry totaling 274 analytes (polycyclic aromatic hydrocarbons, organochlorine compounds, polychlorinated biphenyls, polybrominated diphenyl ethers, trace elements, and current-use pesticides) and a mixture assessment based on the ratios of detected compounds to available effects-based benchmarks. The sediments were tested for toxicity with the amphipod Hyalella azteca (28-d exposure), the midge Chironomus dilutus (10-d), and, at a few sites, with the freshwater mussel Lampsilis siliquoidea (28-d). Sediment concentrations, normalized to organic carbon content, infrequently exceeded benchmarks for aquatic health, which was generally consistent with low rates of observed toxicity. However, the benchmark-based mixture score and the pyrethroid insecticide bifenthrin were significantly related to observed sediment toxicity. The sediment mixture score and bifenthrin were also significant predictors of the upper limits of several univariate measures of the macroinvertebrate community (EPT percent, MMI (Macroinvertebrate Multimetric Index) Score, Ephemeroptera and Trichoptera richness) using quantile regression. Multivariate pattern matching (Mantel-like tests) of macroinvertebrate species per site to identified contaminant metrics and sediment toxicity also indicate that the sediment mixture score and bifenthrin have weak, albeit significant, influence on the observed invertebrate community composition. Together, these three lines of evidence (toxicity tests, univariate metrics, and

  9. Serpentinization-Influenced Groundwater Harbors Extremely Low Diversity Microbial Communities Adapted to High pH

    PubMed Central

    Twing, Katrina I.; Brazelton, William J.; Kubo, Michael D. Y.; Hyer, Alex J.; Cardace, Dawn; Hoehler, Tori M.; McCollom, Tom M.; Schrenk, Matthew O.

    2017-01-01

    Serpentinization is a widespread geochemical process associated with aqueous alteration of ultramafic rocks that produces abundant reductants (H2 and CH4) for life to exploit, but also potentially challenging conditions, including high pH, limited availability of terminal electron acceptors, and low concentrations of inorganic carbon. As a consequence, past studies of serpentinites have reported low cellular abundances and limited microbial diversity. Establishment of the Coast Range Ophiolite Microbial Observatory (California, U.S.A.) allowed a comparison of microbial communities and physicochemical parameters directly within serpentinization-influenced subsurface aquifers. Samples collected from seven wells were subjected to a range of analyses, including solute and gas chemistry, microbial diversity by 16S rRNA gene sequencing, and metabolic potential by shotgun metagenomics, in an attempt to elucidate what factors drive microbial activities in serpentinite habitats. This study describes the first comprehensive interdisciplinary analysis of microbial communities in hyperalkaline groundwater directly accessed by boreholes into serpentinite rocks. Several environmental factors, including pH, methane, and carbon monoxide, were strongly associated with the predominant subsurface microbial communities. A single operational taxonomic unit (OTU) of Betaproteobacteria and a few OTUs of Clostridia were the almost exclusive inhabitants of fluids exhibiting the most serpentinized character. Metagenomes from these extreme samples contained abundant sequences encoding proteins associated with hydrogen metabolism, carbon monoxide oxidation, carbon fixation, and acetogenesis. Metabolic pathways encoded by Clostridia and Betaproteobacteria, in particular, are likely to play important roles in the ecosystems of serpentinizing groundwater. These data provide a basis for further biogeochemical studies of key processes in serpentinite subsurface environments. PMID:28298908

  10. Serpentinization-Influenced Groundwater Harbors Extremely Low Diversity Microbial Communities Adapted to High pH.

    PubMed

    Twing, Katrina I; Brazelton, William J; Kubo, Michael D Y; Hyer, Alex J; Cardace, Dawn; Hoehler, Tori M; McCollom, Tom M; Schrenk, Matthew O

    2017-01-01

    Serpentinization is a widespread geochemical process associated with aqueous alteration of ultramafic rocks that produces abundant reductants (H2 and CH4) for life to exploit, but also potentially challenging conditions, including high pH, limited availability of terminal electron acceptors, and low concentrations of inorganic carbon. As a consequence, past studies of serpentinites have reported low cellular abundances and limited microbial diversity. Establishment of the Coast Range Ophiolite Microbial Observatory (California, U.S.A.) allowed a comparison of microbial communities and physicochemical parameters directly within serpentinization-influenced subsurface aquifers. Samples collected from seven wells were subjected to a range of analyses, including solute and gas chemistry, microbial diversity by 16S rRNA gene sequencing, and metabolic potential by shotgun metagenomics, in an attempt to elucidate what factors drive microbial activities in serpentinite habitats. This study describes the first comprehensive interdisciplinary analysis of microbial communities in hyperalkaline groundwater directly accessed by boreholes into serpentinite rocks. Several environmental factors, including pH, methane, and carbon monoxide, were strongly associated with the predominant subsurface microbial communities. A single operational taxonomic unit (OTU) of Betaproteobacteria and a few OTUs of Clostridia were the almost exclusive inhabitants of fluids exhibiting the most serpentinized character. Metagenomes from these extreme samples contained abundant sequences encoding proteins associated with hydrogen metabolism, carbon monoxide oxidation, carbon fixation, and acetogenesis. Metabolic pathways encoded by Clostridia and Betaproteobacteria, in particular, are likely to play important roles in the ecosystems of serpentinizing groundwater. These data provide a basis for further biogeochemical studies of key processes in serpentinite subsurface environments.

  11. Transcriptional responses in juvenile Atlantic cod (Gadus morhua) after exposure to mercury-contaminated sediments obtained near the wreck of the German WW2 submarine U-864, and from Bergen Harbor, Western Norway.

    PubMed

    Olsvik, Pål A; Brattås, Marianne; Lie, Kai K; Goksøyr, Anders

    2011-04-01

    The main aim of the present work was to investigate the effects of mercury (Hg)-enriched sediments on fish. Sediments near the sunken German WW2 submarine U-864, which according to historical documents included 67 tons of metallic Hg in its cargo, are enriched of Hg leaking from the wreckage. Juvenile Atlantic cod (Gadus morhua) were exposed to two field-collected polluted sediments (U-864: inorganic Hg and Bergen Harbor (Vågen): inorganic Hg, PCB and PAH) or two comparable reference sediments for 5 weeks in the laboratory, and transcriptional responses evaluated in gills and liver. Gills of fish exposed to the Hg-enriched sunken WW2 submarine U-864 sediment contained four fold higher Hg levels compared to the control fish. An increase in Hg content in liver in the U-864 fish was also observed. The transcriptional results showed that calreticulin, HSP70 and heme oxygenase mRNA were significantly up-regulated in gills in fish exposed to the Hg-enriched sediments, whereas calreticulin, heme oxygenase, transferrin and WAP65 were significantly up-regulated and glutathione peroxidase 4B and zona pellucida 3 were significantly down-regulated in liver tissue. In gills and liver of cod exposed to the mixed-contaminated Vågen sediment, CYP1A showed the highest induction. In conclusion, the experiment shows that sediment-bound Hg is available to the fish and affects the transcription of oxidative stress responsive enzymes, suggesting that the Hg-enriched sediments may negatively affect the local wildlife. Furthermore, the mixed contaminated sediments of Vågen affected similar responses in addition to Ah-receptor mediated responses reflecting exposure to PAHs and PCBs.

  12. Reach-Scale Hydraulic Influence on Sediment Dynamics and Morphological Development in a Bedrock Influenced River

    NASA Astrophysics Data System (ADS)

    Entwistle, N. S.; Heritage, G. L.; Milan, D. J.; Tooth, S.

    2014-12-01

    Many large rivers in southern Africa are characterised by a macro-channel cut 10 - 20 m into the ancient planation surface. This has resulted in a variable channel morphology strongly influenced by bedrock outcrops. The influence of bedrock upon flow hydraulics and sediment transport often results in a repeat sequence of alluvial channel types behind bedrock obstructions. This study investigates the hydraulic controls on channel type sequencing on the Sabie River, which drains a 6500 km2 semi-arid catchment of the Lowveld of South Africa and Mozambique. Aerial LIDAR data within the Kruger National Park was interrogated to isolate a bedrock influenced anastomosing reach, together with its associated alluvial sequences up- and downstream. These data were used to create a 2m DEM and a 2D flow model (JFLOW) was used to simulate a sequence of flows from 20 m3s-1 to 5000 m3s-1, with spatial data on water surface, flow depth and channel velocity extracted from the model. Water surface data revealed the strong gradient control exerted by the bedrock influenced anastomosed channel, creating hydraulic conditions suitable for deposition upstream and restricting sedimentation downstream. Steepening of the gradient through the anastomosing reach resulted in altered hydraulics and a changed pattern of sedimentation. At moderate discharges, flow is distributed efficiently across numerous interconnected channels, over low berms and islands, promoting sedimentation. Similarly the backwater effect encourages deposition of fine sediments upstream to create and maintain the alluvial sequence. Under higher flows, water levels rise significantly in the confined upstream reach and shear stress exceeds the threshold necessary to strip stored sediment. In contrast, conditions within the anastomosed reach remain less energetic due to the continued effect of flow distribution. Under extreme flow conditions the bedrock influence is drowned out resulting in dramatically increased energy levels

  13. ENVIRONMENTAL MONITORING OF REMEDIAL DREDGING AT THE NEW BEDFORD HARBOR, MA, SUPERFUND SITE

    EPA Science Inventory

    New Bedford Harbor (NBH), MA, is a Superfund site due to high sediment polychlorinated biphenyl (PCB) concentrations. An initial remedial dredging operation removed the most contaminated sediments from the upper harbor ("Hot Spot"). During remediation, a monitoring program assess...

  14. Influence of wave and current flow on sediment-carrying capacity and sediment flux at the water-sediment interface.

    PubMed

    Zheng, Jun; Li, Ruijie; Yu, Yonghai; Suo, Anning

    2014-01-01

    In nearshore waters, spatial and temporal scales of waves, tidal currents, and circulation patterns vary greatly. It is, therefore, difficult to combine these factors' effects when trying to predict sediment transport processes. This paper proposes the concept of significant wave velocity, which combines the effects of waves, tides, and ocean currents using the horizontal kinetic energy superposition principle. Through a comparison of the relationship between shear stress at the water-sediment interface and sediment-carrying capacity, assuming equilibrium sediment flux, a new formula for sediment-carrying capacity, which incorporates the concept of significant wave velocities, is derived. Sediment-carrying capacity is a function of the critical velocity, which increases with water depth and decreases with increasing relative roughness of the sea bed. Finally, data from field observation stations and simulations are used to test the proposed formula. The results show that the new formula is in good agreement with both field and simulation data. This new formula for sediment-carrying capacity can be used to simulate nearshore sediment transport.

  15. Influence of suspended kelp culture on seabed sediment composition in Heini Bay, China

    NASA Astrophysics Data System (ADS)

    Liu, Yanxia; Huang, Haijun; Yan, Liwen; Liu, Xiao; Zhang, Zehua

    2016-11-01

    Kelp aquaculture activities occupy large nearshore areas with significant effects on sediment properties, primarily caused by the influence of the suspended kelp on local hydrodynamics. Changes in sediment composition and grain-size distributions were investigated prior to and following the commencement of kelp aquaculture activities in Heini Bay in eastern China. Seabed sediment types and the particulate matter in suspension during the kelp seeding and harvesting periods, and in sediment cores, were analyzed. While suspended sediment in the kelp aquaculture area was up to 20% organic material, sediment organic content on the seabed remained at similar levels as areas lacking aquaculture. The composition of the seabed sediment in the kelp aquaculture area became finer-grained by the capture of fine particles. Within the kelp aquaculture area, the sediments are poorly sorted and positively skewed, whereas at the shoreward and seaward of the aquaculture area the sediments are relatively coarse-grained, well-sorted and nearly symmetrically distributed. Therefore, the kelp aquaculture activities not only increase the fine particulate fraction in the sediments within the aquaculture area, but also result in similar deposits seaward of it, indicating that seabed erosion and accretion is also controlled by the sediment source and the hydrodynamic conditions. The analysis of sediment cores showed that kelp culturing refines the sediment by preferentially capturing particles in the 38-40 μm size class, while having no effect on the <32 μm fractions, as evidenced by the positive skew of the surficial sediments. The captured particle size class became well mixed into the sediment, thereby changing the composition of the sediment in the uppermost layer of the core, indicating the existence of continuous and stable hydrodynamic conditions within the kelp aquaculture area. The same effect was observed in the seabed sediments seaward of the aquaculture area.

  16. Vegetation Influences on Tidal Freshwater Marsh Sedimentation and Accretion

    NASA Astrophysics Data System (ADS)

    Cadol, D. D.; Elmore, A. J.; Engelhardt, K.; Palinkas, C. M.

    2011-12-01

    Continued sea level rise, and the potential for acceleration over the next century, threatens low-lying natural and cultural resources throughout the world. In the national capital region of the United States, for example, the National Park Service manages over 50 km^2 of land along the shores of the tidal Potomac River and its tributaries that may be affected by sea level rise. Dyke Marsh Wildlife Preserve on the Potomac River south of Washington, DC, is one such resource with a rich history of scientific investigation. It is a candidate for restoration to replace marsh area lost to dredging in the 1960s, yet for restoration to succeed in the long term, accretion must maintain the marsh surface within the tidal range of rising relative sea level. Marsh surface accretion rates tend to increase with depth in the tidal frame until a threshold depth is reached below which marsh vegetation cannot be sustained. Suspended sediment concentration, salinity, tidal range, and vegetation community all influence the relationship between depth and accretion rate. The complex interactions among these factors make sedimentation rates difficult to generalize across sites. Surface elevation tables (SET) and feldspar marker horizons have been monitored at 9 locations in Dyke Marsh for 5 years, providing detailed data on sedimentation, subsidence, and net accretion rates at these locations. We combine these data with spatially rich vegetation surveys, a LiDAR derived 1-m digital elevation model of the marsh, and temperature-derived inundation durations to model accretion rates across the marsh. Temperature loggers suggest a delayed arrival of tidal water within the marsh relative to that predicted by elevation alone, likely due to hydraulic resistance caused by vegetation. Wave driven coastal erosion has contributed to bank retreat rates of ~2.5 m/yr along the Potomac River side of the marsh while depositing a small berm of material inland of the retreating shoreline. Excluding sites

  17. Sea breeze modulated volatilization of polycyclic aromatic hydrocarbons from the Masnou Harbor (NW Mediterranean Sea).

    PubMed

    Pérez, Sandra; Dachs, Jordi; Barceló, Damià

    2003-09-01

    Harbors, marinas, and coastal environments are impacted by important pollutant loadings, particularly of polycyclic aromatic hydrocarbons (PAHs). Air-water exchange is an important process driving the environmental fate of organic pollutants in aquatic environments. However, its relevance as a factor affecting the environmental fate of pollutants from harbor sediments and waters has not been properly assessed, so far, except for few coastal environments. The objective of this study is to quantify the importance of volatilization losses of PAHs from harbor sediments and waters and to study the potential role of sea breeze as a modulator of air-water exchange in coastal environments. The results show that volatilization fluxes from a medium size marina located in the NW Mediterranean sea are relatively high in comparison to those observed in other aquatic systems, particularly for the low molecular weight (MW) compounds. This is consistent with PAHs profiles observed in harbor sediments, which are depleted by the lower MW hydrocarbons. Therefore, volatilization is an important loss of low MW PAHs such as phenanthrene, methyl phenanthrene, dibenzothiophene, etc. Indeed, these PAHs have a residence time of few days in the harbor waters and sediments. Finally, the diurnal trends in volatilization fluxes mimics that of the sea breeze influenced wind speed. These results show the important role that the diurnal sea breeze exerts on the environmental fate of pollutants such as PAHs in coastal environments as a modulator of air-water exchange and as a potential driver of transport of pollutants between adjacent coastal and terrestrial environments.

  18. Influence of estuarine sediment on virus survival under field conditions.

    PubMed

    LaBelle, R L; Gerba, C P

    1980-04-01

    The survival of poliovirus 1 (LSc) and echovirus 1 (Farouk) in estuarine water and sediment was studied in Galveston Bay, Texas. Viruses were suspended in estuarine water and sediment both in dialysis tubing and in chambers constructed with polycarbonate membrane walls. Virus inactivation rates in seawater were similar in both types of chambers. Virus adsorption to sediment greatly increased survival time. The time required to inactivate 99% (T-99) of poliovirus increased from 1.4 days in seawater alone to 6.0 days for virus adsorbed to sediment at a relatively nonpolluted site. At a more polluted site, poliovirus T-99 was increased from approximately 1 h to 4925 days by virus adsorption to sediment. This study demonstrates that under field conditions virus association with estuarine sediment acts to prolong its survival in the marine environment.

  19. Influence of biochar amendments on marine sediment trace metal bioavailability

    NASA Astrophysics Data System (ADS)

    Gehrke, G. E.; Hsu-Kim, H.

    2014-12-01

    Biochar has become a desirable material for use in agricultural application to enhance soil quality and in-situ soil and sediment remediation to immobilize organic contaminants. We investigated the effects of biochar sediment amendments on the bioavailability of a suite of inorganic trace metals (Cr, Co, Ni, Cu, Zn, Pb) in contaminated sediments from multiple sites in Elizabeth River, VA. We incubated sediments in microcosms with a variety of water column redox and salinity conditions and compared sediments amended with two types of woody biochar to sediments amended with charcoal activated carbon and unamended sediments. We leached sediments in artificial gut fluid mimic of the benthic invertebrate Arenicola marina as a measure of bioavailability of the trace metals analyzed. In unamended anaerobic sediments, the gut fluid mimic leachable fraction of each trace metal is 1-4% of the total sediment concentration for each metal. Initial results indicate that in anaerobic microcosms, woody biochar sediment amendments (added to 5% dry wt) decrease the gut fluid mimic leachable fraction by 30-90% for all trace metals analyzed, and have comparable performance to charcoal activated carbon amendments. However, in microcosms without controlled redox conditions, woody biochar amendments increase the bioavailable fraction of Ni and Cu by up to 80%, while decreasing the bioavailable fraction of Co, Zn, and Pb by approximately 50%; charcoal activated carbon amendments decreased the bioavailability of all trace metals analyzed by approximately 20%. In microcosms without an overlying water column, biochar and activated carbon amendments had no significant effects on trace metal bioavailability. This research demonstrates that biochar can effectively decrease the bioavailability of trace metals in marine sediments, but its efficiency is metal-specific, and environmental conditions impact biochar performance.

  20. Evaluating physical and biological influences on sedimentation in a tidal freshwater marsh with 7Be

    NASA Astrophysics Data System (ADS)

    Palinkas, Cindy M.; Engelhardt, Katharina A. M.; Cadol, Dan

    2013-09-01

    Key differences exist between tidal fresh- and saltwater marshes, such as the relative importance of mineral versus organic sedimentation and plant species diversity, that likely result in different drivers of sedimentation. In tidal freshwater marshes, we hypothesize that vegetation composition, along with physical marsh features (i.e., elevation and tidal channels), play a critical role in sedimentation. This hypothesis is evaluated in Dyke Marsh Preserve (Potomac River, VA, USA) by examining sediment character (grain size, organic content) and deposition rates across the marsh in spring and summer 2010 and 2011. 7Be is especially well suited to capture seasonal sedimentation patterns owing to its short half-life (53.3 d) and ability to assess both sediment deposition and erosion. However, its use in marshes can be challenging, especially due the presence of vegetation. In this study, 7Be-derived sedimentation rates are compared with sediment deposition observed on ceramic tiles to assess its utility in tidal freshwater marshes, and biophysical influences on sediment deposition are examined through statistical models. 7Be- and tile-derived sedimentation rates show similar spatial and temporal patterns, with highest rates occurring at sites closer to tidal channels, highlighting the importance of sediment availability. In addition, complex feedbacks between sedimentation and the plant community are discussed.

  1. Caffeine in an Urbanized Estuary: Past and Present Influence of Wastewater Effluents in Boston Harbor, MA, USA

    EPA Science Inventory

    Caffeine has been identified by previous research as a potential tracer of sanitary wastewater. To further assess the utility of caffeine as a tracer of wastewater sources, samples from 25 sites throughout Boston Harbor were collected and analyzed for caffeine by LC-MS/MS. Caff...

  2. Caffeine in an Urbanized Estuary: Past and Present Influence of Wastewater Effluents in Boston Harbor, MA, USA

    EPA Science Inventory

    Caffeine has been identified by previous research as a potential tracer of sanitary wastewater. To further assess the utility of caffeine as a tracer of wastewater sources, samples from 25 sites throughout Boston Harbor were collected and analyzed for caffeine by LC-MS/MS. Caff...

  3. Three-dimensional visualization maps of suspended-sediment concentrations during placement of dredged material in 21st Avenue West Channel Embayment, Duluth-Superior Harbor, Duluth, Minnesota, 2015

    USGS Publications Warehouse

    Groten, Joel T.; Ellison, Christopher A.; Mahoney, Mollie H.

    2016-06-30

    Excess sediment in rivers and estuaries poses serious environmental and economic challenges. The U.S. Army Corps of Engineers (USACE) routinely dredges sediment in Federal navigation channels to maintain commercial shipping operations. The USACE initiated a 3-year pilot project in 2013 to use navigation channel dredged material to aid in restoration of shoreline habitat in the 21st Avenue West Channel Embayment of the Duluth-Superior Harbor. Placing dredged material in the 21st Avenue West Channel Embayment supports the restoration of shallow bay aquatic habitat aiding in the delisting of the St. Louis River Estuary Area of Concern.The U.S. Geological Survey, in cooperation with the USACE, collected turbidity and suspended-sediment concentrations (SSCs) in 2014 and 2015 to measure the horizontal and vertical distribution of SSCs during placement operations of dredged materials. These data were collected to help the USACE evaluate the use of several best management practices, including various dredge material placement techniques and a silt curtain, to mitigate the dispersion of suspended sediment.Three-dimensional visualization maps are a valuable tool for assessing the spatial displacement of SSCs. Data collection was designed to coincide with four dredged placement configurations that included periods with and without a silt curtain as well as before and after placement of dredged materials. Approximately 230 SSC samples and corresponding turbidity values collected in 2014 and 2015 were used to develop a simple linear regression model between SSC and turbidity. Using the simple linear regression model, SSCs were estimated for approximately 3,000 turbidity values at approximately 100 sampling sites in the 21st Avenue West Channel Embayment of the Duluth-Superior Harbor. The estimated SSCs served as input for development of 12 three-dimensional visualization maps.

  4. Marine sediments in Disko Trough reveal meltwater-influenced sedimentation during ice-stream retreat

    NASA Astrophysics Data System (ADS)

    Hogan, Kelly A.; Cofaigh, Colm Ó.; Jennings, Anne E.; Dowdeswell, Julian A.

    2015-04-01

    Marine geophysical data from middle and outer Disko Trough, West Greenland reveal thick (more than ten metres) acoustically-laminated, fine-grained sediments between subglacial tills at their base and post-glacial marine sediments at the seafloor. These sediments are interpreted as a transitional facies deposited as ice retreated from the trough during deglaciation. New sediment-core records indicate that these units were likely deposited by meltwater plumes emanating from a nearby grounded-ice margin, probably during stillstands in ice retreat. The retreat of ice in the trough may have been stabilised at a narrowing in DiskoTrough on the mid-shelf, as well as at the basalt escarpment south of Disko Island. Such thicknesses of deglacial or "transitional" glacimarine sediments are relatively unusual on high-latitude continental shelves and indicate a significant meltwater production in central West Greenland during deglaciation. This is consistent with the seafloor landforms in the inner and middle parts of the trough that include channels and moats around bedrock protrusions that look to have been eroded by water. IRD counts from the cores indicate that iceberg rafting also occurred during this transitional phase but that this signal was diluted by the fine-grained transitional sediments. Once ice had withdrawn from the area and sedimentation was hemipelagic in nature the IRD signal was less diluted.

  5. Colorado River sediment transport 1. Natural sediment supply limitation and the influence of Glen Canyon Dam

    USGS Publications Warehouse

    Topping, D.J.; Rubin, D.M.; Vierra, L.E.

    2000-01-01

    Analyses of flow, sediment-transport, bed-topographic, and sedimentologic data suggest that before the closure of Glen Canyon Dam in 1963, the Colorado River in Marble and Grand Canyons was annually supply-limited with respect to fine sediment (i.e., sand and finer material). Furthermore, these analyses suggest that the predam river in Glen Canyon was not supply-limited to the same degree and that the degree of annual supply limitation increased near the head of Marble Canyon. The predam Colorado River in Grand Canyon displays evidence of four effects of supply limitation: (1) seasonal hysteresis in sediment concentration, (2) seasonal hysteresis in sediment grain size coupled to the seasonal hysteresis in sediment concentration, (3) production of inversely graded flood deposits, and (4) development or modification of a lag between the time of a flood peak and the time of either maximum or minimum (depending on reach geometry) bed elevation. Analyses of sediment budgets provide additional support for the interpretation that the predam river was annually supply-limited with respect to fine sediment, but it was not supply-limited with respect to fine sediment during all seasons. In the average predam year, sand would accumulate and be stored in Marble Canyon and upper Grand Canyon for 9 months of the year (from July through March) when flows were dominantly below 200-300 m3/s; this stored sand was then eroded during April through June when flows were typically higher. After closure of Glen Canyon Dam, because of the large magnitudes of the uncertainties in the sediment budget, no season of substantial sand accumulation is evident. Because most flows in the postdam river exceed 200-300 m3/s, substantial sand accumulation in the postdam river is unlikely.

  6. Indiana Harbor Canal Great Lakes Legacy Act Cleanup

    EPA Pesticide Factsheets

    Indiana Department of Environmental Management are investigating an off-site disposal option for the dredged sediments removal and capping of deepe rcontaminated sediment “hot spots” in the Indiana Harbor Canal.

  7. Comparative phosphorus sorption by marine sediments and agricultural soils in a tropical environment.

    PubMed

    Fox, Robert L; Fares, Ali; Wan, Y; Evensen, Carl I

    2006-01-01

    The influence of soil phosphorus (P) sources on P sorption characteristics of marine sediments was investigated for Pearl Harbor and off shore Molokai in Hawaii. Estuary sediments were sampled in seven locations; these represented different soils and on-shore activities. The soil samples included nine major soils that contributed sediment to the Harbor and coastal sediments near the island of Molokai. Sediment and soil samples were equilibrated for 6 days in 0.01 M CaCl(2) solution and synthetic seawater containing differing amounts of P. Phosphorus sorption curves were constructed. The equilibrated solution P, with no P added, ranged from 0.01 to 0.2 mg L(-1); P sorption by sediments at standard solution concentration 0.2 mg L(-1), ranged from 0 to 230 mg kg(-1). Sediment P sorption corresponded closely with soil sorption characteristics. Soils contributing sediments to the west reach of Pearl Harbor are highly weathered Oxisols with high standard P sorption values while those in the southeast of the Harbor were Vertisols and Mollisols which sorb little P. The influence of source materials on sediment P sorption was also observed for off-shore sediments near Molokai. Sediments serve as both source and sink for P in Pearl Harbor and in this role can be a stabilizing influence on P concentration in the water column. Phosphorus sorption curves in conjunction with water quality data can help to understand P dynamics between sediments and the water column and help evaluate concerns about P loading to a water body. For Pearl Harbor, solution P in equilibrium with sediments from the Lochs was 0.021 mg L(-1); a value unlikely to produce an algal bloom. (Measured total P in the water columns (mean) was 0.060.).

  8. Periodic sediment shift in migrating ripples influences benthic microbial activity

    NASA Astrophysics Data System (ADS)

    Zlatanović, Sanja; Fabian, Jenny; Mendoza-Lera, Clara; Woodward, K. Benjamin; Premke, Katrin; Mutz, Michael

    2017-06-01

    Migrating bedforms have high levels of particulate organic matter and high rates of pore water exchange, causing them to be proposed as hot spots of carbon turnover in rivers. Yet, the shifting of sediments and associated mechanical disturbance within migrating bedforms, such as ripples, may stress and abrade microbial communities, reducing their activity. In a microcosm experiment, we replicated the mechanical disturbances caused by the periodic sediment shift within ripples under oligotrophic conditions. We assessed the effects on fungal and bacterial biomass ratio (F:B), microbial community respiration (CR), and bacterial production (BCP) and compared with stable undisturbed sediments. Interactions between periodic mechanical disturbance and sediment-associated particulate organic matter (POM) were tested by enriching sediments collected from migrating ripples with different qualities of POM (fish feces, leaf litter fragments and no addition treatments). F:B and BCP were affected by an interaction between mechanical disturbance and POM quality. Fish feces enriched sediments showed increased F:B and BCP compared to sediments with lower POM quality and responded with a decrease of F:B and BCP to sediment disturbance. In the other POM treatments F:B and BCP were not affected by disturbance. Microbial respiration was however reduced by mechanical disturbance to similar low activity levels regardless of POM qualities added, whereas fish feces enriched sediment showed short temporary boost of CR. With the worldwide proliferation of migrating sand ripples due to massive catchment erosion, suppressed mineralization of POM will increasingly affect stream metabolism, downstream transport of POM and carbon cycling from reach to catchment scale.

  9. Sediment dynamics and their potential influence on insular-slope mesophotic coral ecosystems

    NASA Astrophysics Data System (ADS)

    Sherman, C.; Schmidt, W.; Appeldoorn, R.; Hutchinson, Y.; Ruiz, H.; Nemeth, M.; Bejarano, I.; Motta, J. J. Cruz; Xu, H.

    2016-10-01

    Although sediment dynamics exert a fundamental control on the character and distribution of reefs, data on sediment dynamics in mesophotic systems are scarce. In this study, sediment traps and benthic photo-transects were used to document spatial and temporal patterns of suspended-sediment and bed-load dynamics at two geomorphically distinct mesophotic coral ecosystems (MCEs) on the upper insular slope of southwest Puerto Rico. Trap accumulation rates of suspended sediment were relatively low and spatiotemporally uniform, averaging <1 mg cm-2 d-1 and never exceeding 3 mg cm-2 d-1 over the sampled period. In contrast, trap accumulation rates of downslope bed-load movement were orders of magnitude higher than suspended-sediment accumulation rates and highly variable, by orders of magnitude, both spatially and temporally. Percent sand cover within photo-transects varied over time from 10% to more than 40% providing further evidence of downslope sediment movement. In general, the more exposed, lower gradient site had higher rates of downslope sediment movement, higher sand cover and lower coral cover than the more sheltered and steep site that exhibited lower rates of downslope sediment movement, lower sand cover and higher coral cover. In most cases, trap accumulation rates of suspended sediment and bed load varied together and peaks in trap accumulation rates correspond to peaks in SWAN-modeled wave-orbital velocities, suggesting that surface waves may influence sediment dynamics even in mesophotic settings. Though variable, off-shelf transport of sediment is a continuous process occurring even during non-storm conditions. Continuous downslope sediment movement in conjunction with degree of exposure to prevailing seas and slope geomorphology are proposed to exert an important influence on the character and distribution of insular-slope MCEs.

  10. Decadal Changes In Benthic Community Measures In New York Harbor

    EPA Science Inventory

    Monitoring in New York Harbor, NY, as part of the Regional Environmental Monitoring and Assessment Program has spanned a decade, and includes habitat and water quality measures and sediment contaminant levels from four sub-basins (Upper NY Harbor, Lower NY Harbor, Newark Bay, and...

  11. Decadal Changes In Benthic Community Measures In New York Harbor

    EPA Science Inventory

    Monitoring in New York Harbor, NY, as part of the Regional Environmental Monitoring and Assessment Program has spanned a decade, and includes habitat and water quality measures and sediment contaminant levels from four sub-basins (Upper NY Harbor, Lower NY Harbor, Newark Bay, and...

  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. 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...

  14. Hierarchy of factors which influence polycyclic aromatic hydrocarbons (PAHs) distribution in river sediments.

    PubMed

    Liu, An; Duodu, Godfred O; Mummullage, Sandya; Ayoko, Godwin A; Goonetilleke, Ashantha

    2017-04-01

    The sediment environment provides habitat for fauna and flora. As pollutants can interchange between water and sediments, pollution will exert a significant influence on the water environment. Previous studies on polycyclic aromatic hydrocarbon (PAHs) pollution of sediments have primarily focused on the comparison of concentrations between seasons, land uses and species. Studies on the identification of the hierarchy of factors which influence PAHs distribution and its variability in river sediments are limited. This paper discusses a comprehensive investigation into the inherent variability of PAHs in sediments and the primary factors which influence this variability. The study outcomes confirmed that key factors exerting influence on PAH distribution in sediments can be ranked in the order: land use > population > seasons. Accordingly, intensive urban land use was identified as the most important factor influencing PAHs distribution. Additionally, it was found that with increasing urban development, PAHs concentrations and their variability in sediments increase in terms of the molecular weight of different species. The study outcomes are expected to enhance management strategies to mitigate PAHs pollution of urban water environments including the prioritisation of factors requiring management and the selection of appropriate approaches in the context of cost-effectiveness. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Metal speciation in salt marsh sediments: Influence of halophyte vegetation in salt marshes with different morphology

    NASA Astrophysics Data System (ADS)

    Pedro, Sílvia; Duarte, Bernardo; Raposo de Almeida, Pedro; Caçador, Isabel

    2015-12-01

    Salt marshes provide environmental conditions that are known to affect metal speciation in sediments. The elevational gradient along the marsh and consequent differential flooding are some of the major factors influencing halophytic species distribution and coverage due to their differential tolerance to salinity and submersion. Different species, in turn, also have distinct influences on the sediment's metal speciation, and its metal accumulation abilities. The present work aimed to evaluate how different halophyte species in two different salt marshes could influence metal partitioning in the sediment at root depth and how that could differ from bare sediments. Metal speciation in sediments around the roots (rhizosediments) of Halimione portulacoides, Sarcocornia fruticosa and Spartina maritima was determined by sequentially extracting operationally defined fractions with solutions of increasing strength and acidity. Rosário salt marsh generally showed higher concentrations of all metals in the rhizosediments. Metal partitioning was primarily related to the type of metal, with the elements' chemistry overriding the environment's influence on fractionation schemes. The most mobile elements were Cd and Zn, with greater availability being found in non-vegetated sediments. Immobilization in rhizosediments was predominantly influenced by the presence of Fe and Mn oxides, as well as organic complexes. In the more mature of both salt marshes, the differences between vegetated and non-vegetated sediments were more evident regarding S. fruticosa, while in the younger system all halophytes presented significantly different metal partitioning when compared to that of mudflats.

  16. Influence of sediment presence on freshwater mussel thermal tolerance

    USGS Publications Warehouse

    Archambault, Jennifer M.; Cope, W. Gregory; Kwak, Thomas J.

    2014-01-01

    Median lethal temperature (LT50) data from water-only exposures with the early life stages of freshwater mussels suggest that some species may be living near their upper thermal tolerances. However, evaluation of thermal sensitivity has never been conducted in sediment. Mussels live most of their lives burrowed in sediment, so understanding the effect of sediment on thermal sensitivity is a necessary step in evaluating the effectiveness of the water-only standard method, on which the regulatory framework for potential thermal criteria currently is based, as a test of thermal sensitivity. We developed a method for testing thermal sensitivity of juvenile mussels in sediment and used the method to assess thermal tolerance of 4 species across a range of temperatures common during summer. Stream beds may provide a thermal refuge in the wild, but we hypothesized that the presence of sediment alone does not alter thermal sensitivity. We also evaluated the effects of 2 temperature acclimation levels (22 and 27°C) and 2 water levels (watered and dewatered treatments). We then compared results from the sediment tests to those conducted using the water-only standard methods. We also conducted water-only LT tests with mussel larvae (glochidia) for comparison with the juvenile life stage. We found few consistent differences in thermal tolerance between sediment and water-only treatments, between acclimation temperatures, between waterlevel treatments, among species, or between juvenile and glochidial life stages (LT50 range = 33.3-37.2°C; mean = 35.6°C), supporting our hypothesis that the presence of sediment alone does not alter thermal sensitivity. The method we developed has potential for evaluating the role of other stressors (e.g., contaminants) in a more natural and complex environment.

  17. 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.

  18. Monsoon sedimentation on the ‘abandoned' tide-influenced Ganges-Brahmaputra delta plain

    NASA Astrophysics Data System (ADS)

    Rogers, Kimberly G.; Goodbred, Steven L.; Mondal, Dhiman R.

    2013-10-01

    Annual sediment delivery by the Ganges and Brahmaputra rivers to the Bengal margin has kept pace with sea level rise since the mid Holocene, sustaining subaerial growth of the delta. However, the Sundarbans region of the tidal delta is disconnected from major distributary sources of sediment and is often thought to be sediment starved, eroding, and susceptible to the meter of sea level rise predicted for the 21st century. Despite these assumptions, direct sedimentation measurements on the tidal delta plain reveal widespread mean annualized accretion rates of ˜1.1 cm yr-1, although heterogeneous depositional patterns indicate that topography and internal creek networks influence local sediment distribution. Short-lived radioisotope inventories (7Be: t1/2 = 53.3 days) measured on the freshly accumulated sediments indicate that about ½ of the mass deposited on the lower delta was sourced directly from the seasonal flood pulse of the river; the remaining ½ is derived from older (≥1 yr) reworked sediments. Net sedimentation on this part of the delta traps ˜10% of annual Ganges-Brahmaputra sediment load, with accretion rates roughly equivalent to the mean regional rate of relative sea-level rise (RSLR) of ˜1.0 cm yr-1. If these sedimentation rates are representative of longer-term trends and subsidence rates remain stable over the next century, the lower delta plain may continue to maintain its elevation and stability despite documented mangrove retreat around its seaward edges.

  19. Sedimentation

    Treesearch

    Cliff R. Hupp; Michael R. Schening

    2000-01-01

    Sedimentation is arguably the most important water-quality concern in the United States. Sediment trapping is cited frequently as a major function of riverine-forested wetlands, yet little is known about sedimcntation rates at the landscape scale in relation to site parameters, including woody vegetation type, elevation, velocity, and hydraulic connection to the river...

  20. Modeling nonlinear sorption of alcohol ethoxylates to sediment: the influence of molecular structure and sediment properties.

    PubMed

    Droge, Steven T J; Yarza-Irusta, Leire; Hermens, Joop L M

    2009-08-01

    The nonlinear sorption of individual alcohol ethoxylate (AE) homologues was studied as a function of the chemical structure of AE and properties of six marine sediments and three clay minerals. All sorption data for both sediments and clays are well described by a dual-mode model, combining a Langmuir and linear sorption term. The nonlinear isotherms of a single homologue on different substrates almost overlap when sorbed concentrations are expressed per specific surface area. Below and above the Langmuir maximum capacity, isotherms approach linearity. Accordingly, it is demonstrated for nine individual AE that the two linear sorption coefficients for the clay mineral illite are predictive within a factor of two for a North Sea sediment. The linear sorption term at high concentrations is likely related to bilayer formation on the mineral surfaces, for both clays and sediments. Adsorption and bilayer formation to mineral surfaces dominate the sorption behavior of most AE homologues to the tested marine sediments. The two fitted sorption coefficients correlate well with the polar and nonpolar chain lengths of the AE. The enhanced nonlinearity of isotherms for AE with longer ethoxylate chains is explained by both an increasing adsorption coefficient and a decreasing bilayer formation affinity with additional ethoxylate units.

  1. Influence of Macrofaunal Burrows on Extracellular Enzyme Activity and Microbial Abundance in Subtropical Mangrove Sediment.

    PubMed

    Luo, Ling; Gu, Ji-Dong

    2016-09-13

    Bioturbation and bioirrigation induced by burrowing macrofauna are recognized as important processes in aquatic sediment since macrofaunal activities lead to the alteration of sediment characteristics. However, there is a lack of information on how macrofauna influence microbial abundance and extracellular enzyme activity in mangrove sediment. In this study, the environmental parameters, extracellular enzyme activities, and microbial abundance were determined and their relationships were explored. Sediment samples were taken from the surface (S) and lower layer (L) without burrow, as well as crab burrow wall (W) and bottom of crab burrow (B) located at the Mai Po Nature Reserve, Hong Kong. The results showed that the burrowing crabs could enhance the activities of oxidase and hydrolases. The highest activities of phenol oxidase and acid phosphatase were generally observed in B sediment, while the highest activity of N-acetyl-glucosaminidase was found in W sediment. The enzymatic stoichiometry indicated that the crab-affected sediment had similar microbial nitrogen (N) and phosphorous (P) availability relative to carbon (C), lower than S but higher than L sediment. Furthermore, it was found that the highest abundance of both bacteria and fungi was shown in S sediment, and B sediment presented the lowest abundance. Moreover, the concentrations of phosphorus and soluble phenolics in crab-affected sediment were almost higher than the non-affected sediment. The alterations of phenolics, C/P and N/P ratios as well as undetermined environmental factors by the activities of crabs might be the main reasons for the changes of enzyme activity and microbial abundance. Finally, due to the important role of phenol oxidase and hydrolases in sediment organic matter (SOM) decomposition, it is necessary to take macrofaunal activities into consideration when estimating the C budget in mangrove ecosystem in the future.

  2. Polycyclic aromatic hydrocarbons (PAHs) in coastal sediments from urban and industrial areas of Asaluyeh Harbor, Iran: distribution, potential source and ecological risk assessment.

    PubMed

    Raeisi, Alireza; Arfaeinia, Hossein; Seifi, Morteza; Shirzad-Siboni, Mehdi; Keshtkar, Mozhgan; Dobaradaran, Sina

    The distribution and toxicity levels of 16 EPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) in the sediments of Asaluyeh shore, Iran were investigated. The total concentrations of the PAHs in surface sediments ranged from 1,054 to 17,448 ng/g dry weights with a mean concentration of 8,067 ng/g. The spatial distribution of PAHs showed that PAH levels are much higher in the industrial areas in comparison with urban areas. Based on diagnostic ratios, pyrogenic activities were dominant sources of PAHs pollution in sediments comparing petroleum sources. The toxic equivalent concentrations (TEQ Carc) of PAHs ranged from 172 to 2,235 ng TEQ/g with mean value of 997.9. Toxicity levels were evaluated using sediment quality guidelines (SQGs) and toxic equivalent factors. Samples were collected from industrial and urban stations in Asaluyeh shores. According to SQGs, ΣPAHs concentrations in sediments of urban areas were below the ERL (effects range low), but the industrial samples had ΣPAHs concentrations between ERL and ERM (effects range median). Furthermore, ΣHPAHs (heavy PAHs) and some individual PAHs in some industrial stations exceeded ERM, indicating adverse ecological risk effects frequently occur. Findings demonstrate that the surface sediment from Asaluyeh shore is highly to very highly contaminated with PAHs.

  3. Influences of sediment properties and macrophytes on phosphorous speciation in the intertidal marsh.

    PubMed

    Shao, Xuexin; Liang, Xinqiang; Wu, Ming; Gu, Binhe; Li, Wenhua; Sheng, Xuancai; Wang, Shaoxian

    2014-09-01

    Phosphorus (P) in wetlands is mainly bound to sediment in various species, which is essential to predict water column P levels. The purpose of this work is to understand the influences of sediment properties and vegetation types on P speciation. Sediments under four vegetation types in the tidal flat and offshore sandbar in Hangzhou Bay of China were collected seasonally. The rank order of P species in sediment based on concentration was exchangeable P (Exch-P) < iron/aluminum-bound P (Fe/Al-P) < organic P (Org-P) < calcium-bound P (Ca-P). Sediment total phosphorus (TP) and Fe/Al-P concentrations were lower in offshore sandbar than those of tidal flat, reflecting effects of anthropogenic contamination in the latter. Sediment particle size distribution strongly affected P speciation, as indicated by a significant correlation between them. Total phosphorus and Org-P concentrations in vegetated sediments were higher than those of bare mudflat. Additionally, there was a significant negative correlation between Ca-P and Org-P, and Fe/Al-P, indicating the presence of vegetation which may result in P speciation by converting Ca-P to soluble and active P and higher Org-P. Overall, sediment particle size distribution is the most fundamental physical property that affects P speciation, and vegetation types are important factors that influence Org-P concentration.

  4. Terrigenous transportation to the Okinawa Trough and the influence of typhoons on suspended sediment concentration

    NASA Astrophysics Data System (ADS)

    Bian, Changwei; Jiang, Wensheng; Song, Dehai

    2010-06-01

    The source and transport mechanisms of land-derived Okinawa Trough sediments were studied using the field data of temperature, salinity and turbidity in the East China Seas. The results suggest that there are two primary sediments sources from the Chinese Mainland to the Okinawa Trough: one is the Old Huanghe River submarine delta, and the other is the Changjiang River sediments, which are distributed at the Changjiang River estuary and the off-coast of Zhejiang and Fujian provinces. It is difficult for the Huanghe River suspended sediments to arrive in the Okinawa Trough via the new estuary. Although the Taiwan warm current blocks the seaward terrigenous transportation to a certain extent, part of the coastal suspended sediments are transported to the outer shelf. Suspended particulate matter is unable to get through the barrier of the Kuroshio Current under normal conditions. However, episodic events, such as winter storms, internal-tidal waves and turbidity flows, are capable of transporting suspended particulate matter into the Okinawa Trough. The super typhoon "Ewiniar" induced strong waves and influenced the thermocline depth and suspended sediment concentration of the East China Seas. The typhoon-induced waves pushed the thermocline depth down to around 40 m and caused the resuspension of large volumes of sediments in its path. In the other East China Seas regions, the typhoon-induced swells deepened the thermocline depth by about 5 m and increased suspended sediment concentrations. The typhoon effect on suspended sediment concentration of the East China Seas disappeared within 2 weeks.

  5. Microbial diversity and community respiration in freshwater sediments influenced by artificial light at night.

    PubMed

    Hölker, Franz; Wurzbacher, Christian; Weißenborn, Carsten; Monaghan, Michael T; Holzhauer, Stephanie I J; Premke, Katrin

    2015-05-05

    An increasing proportion of the Earth's surface is illuminated at night. In aquatic ecosystems, artificial light at night (ALAN) may influence microbial communities living in the sediments. These communities are highly diverse and play an important role in the global carbon cycle. We combined field and laboratory experiments using sediments from an agricultural drainage system to examine how ALAN affects communities and alters carbon mineralization. Two identical light infrastructures were installed parallel to a drainage ditch before the start of the experiment. DNA metabarcoding indicated that both sediment communities were similar. After one was lit for five months (July-December 2012) we observed an increase in photoautotroph abundance (diatoms, Cyanobacteria) in ALAN-exposed sediments. In laboratory incubations mimicking summer and winter (six weeks each), communities in sediments that were exposed to ALAN for 1 year (July 2012-June 2013) showed less overall seasonal change compared with ALAN-naive sediments. Nocturnal community respiration was reduced in ALAN-exposed sediments. In long-term exposed summer-sediments, we observed a shift from negative to positive net ecosystem production. Our results indicate ALAN may alter sediment microbial communities over time, with implications for ecosystem-level functions. It may thus have the potential to transform inland waters to nocturnal carbon sinks.

  6. Microbial diversity and community respiration in freshwater sediments influenced by artificial light at night

    PubMed Central

    Hölker, Franz; Wurzbacher, Christian; Weißenborn, Carsten; Monaghan, Michael T.; Holzhauer, Stephanie I. J.; Premke, Katrin

    2015-01-01

    An increasing proportion of the Earth's surface is illuminated at night. In aquatic ecosystems, artificial light at night (ALAN) may influence microbial communities living in the sediments. These communities are highly diverse and play an important role in the global carbon cycle. We combined field and laboratory experiments using sediments from an agricultural drainage system to examine how ALAN affects communities and alters carbon mineralization. Two identical light infrastructures were installed parallel to a drainage ditch before the start of the experiment. DNA metabarcoding indicated that both sediment communities were similar. After one was lit for five months (July–December 2012) we observed an increase in photoautotroph abundance (diatoms, Cyanobacteria) in ALAN-exposed sediments. In laboratory incubations mimicking summer and winter (six weeks each), communities in sediments that were exposed to ALAN for 1 year (July 2012–June 2013) showed less overall seasonal change compared with ALAN-naive sediments. Nocturnal community respiration was reduced in ALAN-exposed sediments. In long-term exposed summer-sediments, we observed a shift from negative to positive net ecosystem production. Our results indicate ALAN may alter sediment microbial communities over time, with implications for ecosystem-level functions. It may thus have the potential to transform inland waters to nocturnal carbon sinks. PMID:25780242

  7. Influence of Reservoir Water Level Fluctuations on Sediment ...

    EPA Pesticide Factsheets

    Mercury (Hg) is a pollutant of global concern due to its ability to accumulate as methylmercury (MeHg) in biota. Mercury is methylated by anaerobic microorganisms such as sulfate reducing bacteria (SRB) in water and sediment. Throughout North America, reservoirs tend to have elevated methylmercury (MeHg) concentrations compared to natural lakes and rivers. This impact is most pronounced in newly created reservoirs where methylation is fueled by the decomposition of flooded organic material, which can release Hg and enhance microbial activity. Much less is known about the longer-term water-level management impacts on Hg cycling in older reservoirs. The objective of our study was to understand the role of on-going water-level fluctuations on sediment MeHg concentrations and sulfur speciation within a reservoir 75 years after initial impoundment. The study was performed at the Cottage Grove Reservoir located 15 km downstream of the historical Black Butte Hg mine. For 8 months each year, the water level is lowered resulting in roughly half of the reservoir’s sediment being exposed to the atmosphere. Water samples from the inflow, water-column, outflow, and sediment were collected seasonally over a year for total-Hg, MeHg, and several ancillary parameters. The results showed that conditions in the reservoir were favorable to methylation with a much higher %MeHg observed in the outflowing water (34%) compared to the inflow (7%) during the late-summer. An

  8. Mississippi and Atchafalaya River Influence on Sediment Porewater Chemistry

    EPA Science Inventory

    The Louisiana continental shelf (LCS) receives 380 km3 of freshwater per year from the Mississippi and Atchafalaya Rivers. Sources and transport of nutrients and organic matter (OM) delivered to the LCS may result in spatial variation in sediment biogeochemistry important for un...

  9. Mississippi and Atchafalaya River Influence on Sediment Porewater Chemistry

    EPA Science Inventory

    The Louisiana continental shelf (LCS) receives 380 km3 of freshwater per year from the Mississippi and Atchafalaya Rivers. Sources and transport of nutrients and organic matter (OM) delivered to the LCS may result in spatial variation in sediment biogeochemistry important for un...

  10. Influence of Reservoir Water Level Fluctuations on Sediment ...

    EPA Pesticide Factsheets

    Mercury (Hg) is a pollutant of global concern due to its ability to accumulate as methylmercury (MeHg) in biota. Mercury is methylated by anaerobic microorganisms such as sulfate reducing bacteria (SRB) in water and sediment. Throughout North America, reservoirs tend to have elevated methylmercury (MeHg) concentrations compared to natural lakes and rivers. This impact is most pronounced in newly created reservoirs where methylation is fueled by the decomposition of flooded organic material, which can release Hg and enhance microbial activity. Much less is known about the longer-term water-level management impacts on Hg cycling in older reservoirs. The objective of our study was to understand the role of on-going water-level fluctuations on sediment MeHg concentrations and sulfur speciation within a reservoir 75 years after initial impoundment. The study was performed at the Cottage Grove Reservoir located 15 km downstream of the historical Black Butte Hg mine. For 8 months each year, the water level is lowered resulting in roughly half of the reservoir’s sediment being exposed to the atmosphere. Water samples from the inflow, water-column, outflow, and sediment were collected seasonally over a year for total-Hg, MeHg, and several ancillary parameters. The results showed that conditions in the reservoir were favorable to methylation with a much higher %MeHg observed in the outflowing water (34%) compared to the inflow (7%) during the late-summer. An

  11. The influence of hydrology on lacustrine sediment contaminant records

    USGS Publications Warehouse

    Rosen, Michael R.

    2015-01-01

    The way water flows to a lake, through streams, as runoff, or as groundwater, can control the distribution and mass of sediment and contaminants deposited. Whether a lake is large or small, deep or shallow, open or closed, the movement of water to a lake and the circulation patterns of water within a lake control how and where sediment and contaminants are deposited. Particle-associated contaminants may stay close to the input source of contamination or be transported by currents to bathymetric lows. A complex morphology of the lake bottom or shoreline can also affect how contaminants will be distributed. Dissolved contaminants may be widely dispersed in smaller lakes, but may be diluted in large lakes away from the source. Although dissolved contaminants may not be deposited in lake sediments, the impact of dissolved contaminants (such as nitrogen) may be reflected by the ecosystem. For instance, increased phosphorus and nitrogen may increase organic content or algal biomass, and contribute to eutrophication of the lake over time. Changes in oxidation-reduction potential at the sediment-water interface may either release some contaminants to the water column or conversely deposit other contaminants to the sediment depending on the compound’s chemical characteristics. Changes in land use generally affect the hydrology of the watershed surrounding a lake, providing more runoff if soil binding vegetation is removed or if more impervious cover (roads and buildings) is increased. Groundwater inputs may change if pumping of the aquifer connected to the lake occurs. Even if groundwater is only a small portion of the volume of water entering a lake, if contaminant concentrations in the aquifer are high compared to surface water inputs, the mass of contaminants from groundwater may be as, or more, important than surface water contributions.

  12. Sorption coefficients of polycyclic aromatic hydrocarbons for two lake sediments: Influence of the bactericide sodium azide

    SciTech Connect

    Maagd, P.G.J. de; Sinnige, T.L.; Schrap, S.M.; Opperhuizen, A.; Sijm, D.T.H.M.

    1998-10-01

    Sorption coefficient s (K{sub p}s) of a series of polycyclic aromatic hydrocarbons (PAHs) were determined in two Dutch freshwater lake sediments to improve the insight into sorption in the aquatic environment. The influence of experimental factors, such as compound concentration, equilibration time, and influence of a bactericide on K{sub p}, was studied. No significant influence of compound concentration on K{sub p} was found. A contact time of 48 h was sufficient to reach equilibrium between PAHs in the sediment and water phase. In the absence of the bactericide, sodium azide, incomplete mass balances, and high K{sub p} of low molecular weight PAHs were found that were not caused by volatilization from, photodegradation in, or sorption by the test system. In the presence of sodium azide, however, high mass balances and lower K{sub p} were found for these compounds. This suggested that significant biodegradation of these compounds occurred in the water phase in the absence of sodium azide. The organic carbon-normalized sorption coefficients (K{sub oc}) of the PAHs in Lake Oostvaardersplassen were two to three times higher than those in Lake Ketelmeer sediment. Although K{sub oc} of the PAHs differed for the two sediments, a clear relationship was found between K{sub oc} and the octanol/water partition coefficient for both sediments and between the K{sub oc} of both sediments. In conclusion, the methodology to determine K{sub p} of biodegradable compounds should include the prevention of bacterial activity, e.g., by addition of sodium azide. Sorption of PAHs in the Dutch lake sediments is determined by the hydrophobicity of the PAH, the organic carbon content of the sediment, and one or more unspecified sediment-specific characteristics.

  13. A qualitative assessment of the influence of bioturbation in Lake Baikal sediments

    NASA Astrophysics Data System (ADS)

    Martin, Patrick; Boes, Xavier; Goddeeris, Boudewijn; Fagel, Nathalie

    2005-04-01

    The impact of bioturbation in Lake Baikal sediments, particularly on rhythmic layering and mixing, was assessed by studying the actual vertical distribution of benthic animals in continuous accumulation zones selected by seismic survey (Vydrino Shoulder, Posolskoe Bank, Continent Ridge). To assess the influence of the bioturbation, animals were extracted from short cores and identified at the relevant taxonomic level. The faunal distribution is examined in parallel with the bioturbation tracks observed in thin section. Oligochaeta, Nematoda, Ostracoda, Copepoda, Gammaridae, Chironomidae and Hydrachnidia were found inhabiting the sediment. Among them, only oligochaete worms were assumed to have a significant impact on sediment mixing because of their "conveyor belt" feeding. The other two most abundantly sampled groups, nematods and copepods, belong to the interstitial fauna that has no significant impact on the vertical displacement of sediment particles and do not ingest the sediment. The presence of a benthic fauna as deep as 15 cm in the sediment indicates that the possibility of sediment disturbance by invertebrate activity cannot be dismissed in Lake Baikal. The effect of biological mixing is more limited in the deepest stations because the number of potential bioturbators is reduced, qualitatively as well as quantitatively. Located in the abyssal zone, Continent and Vydrino (but outside turbidites) deep stations appear to be most promising sediment records for tracking climate signal at high resolution.

  14. Influence of Wastewater Discharge on the Metabolic Potential of the Microbial Community in River Sediments.

    PubMed

    Li, Dong; Sharp, Jonathan O; Drewes, Jörg E

    2016-01-01

    To reveal the variation of microbial community functions during water filtration process in river sediments, which has been utilized widely in natural water treatment systems, this study investigates the influence of municipal wastewater discharge to streams on the phylotype and metabolic potential of the microbiome in upstream and particularly various depths of downstream river sediments. Cluster analyses based on both microbial phylogenetic and functional data collectively revealed that shallow upstream sediments grouped with those from deeper subsurface downstream regions. These sediment samples were distinct from those found in shallow downstream sediments. Functional genes associated with carbohydrate, xenobiotic, and certain amino acid metabolisms were overrepresented in upstream and deep downstream samples. In contrast, the more immediate contact with wastewater discharge in shallow downstream samples resulted in an increase in the relative abundance of genes associated with nitrogen, sulfur, purine and pyrimidine metabolisms, as well as restriction-modification systems. More diverse bacterial phyla were associated with upstream and deep downstream sediments, mainly including Actinobacteria, Planctomycetes, and Firmicutes. In contrast, in shallow downstream sediments, genera affiliated with Betaproteobacteria and Gammaproteobacteria were enriched with putative functions that included ammonia and sulfur oxidation, polyphosphate accumulation, and methylotrophic bacteria. Collectively, these results highlight the enhanced capabilities of microbial communities residing in deeper stream sediments for the transformation of water contaminants and thus provide a foundation for better design of natural water treatment systems to further improve the removal of contaminants.

  15. Sediment replenishment: Influence of the geometrical configuration on the morphological evolution of channel-bed

    NASA Astrophysics Data System (ADS)

    Battisacco, E.; Franca, M. J.; Schleiss, A. J.

    2016-11-01

    Dams trap sediment in the upstream reservoir, which may lead to river bed armoring, streambank erosion and failure, channel incision and reduction of the morphological diversity in the downstream river reaches. The replenishment of sediment is a mitigation measure for this problem to be applied in river reaches downstream of dams. Previously performed field experiments always used one single volume of sediment replenishment. To explore different alternatives, the replenished volume was here divided in four deposits with the motivation to influence also the morphological evolution downstream. Six different geometrical configurations together with three submergence conditions of sediment replenishment were tested for the first time in a laboratory experiment and are herein discussed. The results of the sediment replenishment mitigation technique are described in terms of occupied surface of the flume bed and the temporal evolution of erosion and transport of the introduced sediments. It is shown that, under our experimental conditions, complete submersion of the replenishment volume results in complete erosion of the placed sediment, with a high persistence of the added material along the channel length. The geometrical configuration of the replenishment volume plays a key role for the evolution of bed-forms downstream. Parallel configurations lead to a wider spread of material across the channel. Alternated configurations are suitable to produce sediment clustering and high persistence of placed material in the channel. Observed periodic mounds, considered as the initiating condition for alternate bars, follow a wavelength related to the length of the replenishment when the replenishment volumes are alternating.

  16. Influences of sediment geochemistry on metal accumulation rates and toxicity in the aquatic oligochaete Tubifex tubifex.

    PubMed

    Méndez-Fernández, Leire; De Jonge, Maarten; Bervoets, Lieven

    2014-12-01

    Metal bioaccumulation and toxicity in the aquatic oligochaete Tubifex tubifex exposed to three metal-contaminated field-sediments was studied in order to assess whether sediment-geochemistry (AVS, TOC) plays a major role in influencing these parameters, and to assess if the biodynamic concept can be used to explain observed effects in T. tubifex tissue residues and/or toxicity. An active autotomy promotion was observed in three studied sediments at different time points and reproduction impairment could be inferred in T. tubifex exposed to two of the tested sites after 28 days. The present study showed that sediment metal concentration and tissue residues followed significant regression models for four essential metals (Cu, Co, Ni and Zn) and one non-essential metal (Pb). Organic content normalization for As also showed a significant relationship with As tissue residue. Porewater was also revealed to be an important source of metal uptake for essential metals (e.g. Cu, Ni and Zn) and for As, but AVS content was not relevant for metal uptake in T. tubifex in studied sediments. Under the biodynamic concept, it was shown that influx rate from food (IF, sediment ingestion) in T. tubifex, in a range of sediment geochemistry, was able to predict metal bioaccumulation, especially of the essential metals Cu, Ni and Zn, and for the non-essential metal Pb. Additionally, IF appeared to be a better predictor for metal bioaccumulation in T. tubifex compared to sediment geochemistry normalization.

  17. The influence of vegetation on sedimentation and resuspension of soil particles in small constructed wetlands.

    PubMed

    Braskerud, B C

    2001-01-01

    When initiatives to mitigate soil erosion are insufficient or fail, constructed surface flow wetlands (CWs) could be a final buffer to reduce pollution before reaching recipients. The objective of this study was to determine the influence of CW vegetation on the retention of soil particles from arable land. Retention was measured with water flow-proportional sampling systems in the inlet and outlet, sedimentation traps, and sedimentation plates in four small CWs over a period of 5 yr. The surface area of the CWs was 265 to 900 m2, and the average hydraulic loads were 1.2 to 3.4 m d(-1). Watershed areas were 0.5 to 1.5 km2. Annual soil particle retention was 30 to 80% or 14 to 121 kg m(-2). Results show that macrophytes stimulate sediment retention by mitigating resuspension of CW sediment. Five years after construction, resuspension had decreased approximately 40% and was negligible. As vegetation cover increases, the influence of macrophytes on soil particle retention reaches a level where other factors, such as hydraulic load and sediment load, were more important. Macrophytes increased the hydraulic efficiency by reducing short-circuit or preferential flow. However, vegetation did not have any influence on the clay concentration in the sediment. Hence, a possible stimulation of particle flocculation was not detected. Vegetation makes it possible to use the positive effect of a short particle settling distance in shallow ponds by hindering resuspension.

  18. Erie Harbor, Pennsylvania, Channel Shoaling Analysis

    DTIC Science & Technology

    2011-07-01

    Presque Isle is located on the southern shore of Lake Erie and shelters the federal harbor at Erie , Pennsylvania . The US Army...the evaluation of the shoaling and dredging of sediment materials from Erie Harbor as part of the Presque Isle , Pennsylvania 204 feasibility study...ERDC TR-11-4 1 1 Introduction Problem statement Presque Isle is located on the southern shore of Lake Erie , Pennsylvania at the city of Erie

  19. Influence of granitoid textural parameters on sediment composition: Implications for sediment generation

    NASA Astrophysics Data System (ADS)

    Caracciolo, L.; Tolosana-Delgado, R.; Le Pera, E.; von Eynatten, H.; Arribas, J.; Tarquini, S.

    2012-12-01

    The aim of this study is to determine and characterise the control exerted by parent rock texture on sand composition as a function of grain size. The sands investigated were generated from granitoid parent rocks by the Rhone, Damma and Sidelen glaciers, which drain the Aar Massif in the Central Alps (Switzerland), and were deposited in glacial and fluvio-glacial settings. Mechanical erosion, comminution (crystal breakdown and abrasion) and hydraulic sorting are the most important processes controlling the generation of sediments in this environment, whereas chemical and/or biochemical weathering plays a negligible role. By using a GIS-based Microscopic Information System (MIS), five samples from the glacier-drained portions of the Aar basement have been analysed to determine textural parameters such as modal composition, crystal size distribution and mineral interfaces (types and lengths). Petrographic data of analysed sands include traditional point counts (Gazzi-Dickinson method, minimum of 300 points) as well as textural counts to determine interface types, frequency, and polycrystallinity in phaneritic rock fragments. According to Pettijohn's classification, grain-size dependent compositions vary from feldspathic litharenite (0φ fraction) via lithic arkose (1φ and 2φ) to arkose (3φ and 4φ). Compositional differences among our data set were compared to modern plutoniclastic sands from the Iberian Massif (Spain) and the St. Gabriel Mts. (California, USA), which allowed us to assess the role exerted by glaciers in generating sediments. By combining data from the MIS with those from petrographic analysis, we outlined the evolution of mineral interfaces from the parent rocks to the sediments.

  20. Bioaccumulation Potential of Contaminants from Bedded and Suspended Oakland Harbor Deepening Project Sediments to San Francisco Bay Flatfish and Bivalve Mollusks

    DTIC Science & Technology

    1994-08-01

    4,4’DDT. b. Aroclor 1254 ................ B6 Figure B 11. Contaminant concentrations in sediments. a. Dibutyltin . b. Tributyltin...bioaccumulation in organisms. a. Inner. b. Hot. c. Reference ............... B11 Figure B17. Dibutyltin bioaccumulation in organisms. a. Inner. b. Hot. c... Dibutyltin bioaccumulation from BS and S50. a. Inner. b. Hot. c. Reference ............ E17 Figure B23. Bioaccumulation of metals from Outer BS and S50

  1. Influence of porewater sulfide on methylmercury production and partitioning in sulfate-impacted lake sediments.

    PubMed

    Bailey, Logan T; Mitchell, Carl P J; Engstrom, Daniel R; Berndt, Michael E; Coleman Wasik, Jill K; Johnson, Nathan W

    2017-02-15

    In low-sulfate and sulfate-limited freshwater sediments, sulfate loading increases the production of methylmercury (MeHg), a potent and bioaccumulative neurotoxin. Sulfate loading to anoxic sediments leads to sulfide production that can inhibit mercury methylation, but this has not been commonly observed in freshwater lakes and wetlands. In this study, sediments were collected from sulfate-impacted, neutral pH, surface water bodies located downstream from ongoing and historic mining activities to examine how chronic sulfate loading produces porewater sulfide, and influences MeHg production and transport. Sediments were collected over two years, during several seasons from lakes with a wide range of overlying water sulfate concentration. Samples were characterized for in-situ solid phase and porewater MeHg, Hg methylation potentials via incubations with enriched stable Hg isotopes, and sulfur, carbon, and iron content and speciation. Porewater sulfide reflected historic sulfur loading and was strongly related to the extractable iron content of sediment. Overall, methylation potentials were consistent with the accumulation of MeHg on the solid phase, but both methylation potentials and MeHg were significantly lower at chronically sulfate-impacted sites with a low solid-phase Fe:S ratio. At these heavily sulfate-impacted sites that also contained elevated porewater sulfide, both MeHg production and partitioning are influenced: Hg methylation potentials and sediment MeHg concentrations are lower, but occasionally porewater MeHg concentrations in sediment are elevated, particularly in the spring. The dual role of sulfide as a ligand for inorganic mercury (decreasing bioavailability) and methylmercury (increasing partitioning into porewater) means that elucidating the role of iron and sulfur loads as they define porewater sulfide is key to understanding sulfate's influence on MeHg production and partitioning in sulfate-impacted freshwater sediment.

  2. Sediment fluxes from California Coastal Rivers: the influences of climate, geology, and topography

    USGS Publications Warehouse

    Andrews, E.D.; Antweiler, Ronald C.

    2012-01-01

    The influences of geologic and climatic factors on erosion and sedimentation processes in rivers draining the western flank of the California Coast Range are assessed. Annual suspended, bedload, and total sediment fluxes were determined for 16 river basins that have hydrologic records covering all or most of the period from 1950 to 2006 and have been relatively unaffected by flow storage, regulation, and depletion, which alter the downstream movement of water and sediment. The occurrence of relatively large annual sediment fluxes are strongly influenced by the El Nino–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). The frequency of relatively large annual sediment fluxes decreases from north to south during La Nina phases and increases from north to south during El Nino phases. The influence of ENSO is modulated over a period of decades by the PDO, such that relatively large annual sediment fluxes are more frequent during a La Nina phase in conjunction with a cool PDO and during an El Nino phase in conjunction with a warm PDO. Values of mean annual sediment flux, , were regressed against basin and climatic characteristics. Basin area, bedrock erodibility, basin relief, and precipitation explain 87% of the variation in from the 16 river basins. Bedrock erodibility is the most significant characteristic influencing . Basin relief is a superior predictor of compared with basin slope. is nearly proportional to basin area and increases with increasing precipitation. For a given percentage change, basin relief has a 2.3-fold greater effect on than a similar change in precipitation. The estimated natural from all California coastal rivers for the period 1950–2006 would have been approximately 85 million tons without flow storage, regulation, and depletion; the actual has been approximately 50 million tons, because of the effects of flow storage, regulation, and depletion.

  3. Submarine Groundwater Discharge in Stony Brook Harbor, NY

    NASA Astrophysics Data System (ADS)

    Durand, J. M.; Young, C.; Wong, T.; Hanson, G. N.

    2012-12-01

    As nutrients can significantly impact coastal ecosystems, understanding their path to embayments and oceans is crucial. In Stony Brook Harbor (Long Island, NY), submarine groundwater discharge (SGD) is the only significant contribution of freshwater and thus constitutes the main pathway for nutrients, which may eventually reach Long Island Sound. Subterranean estuaries have been shown to be highly reactive zones where nitrogen attenuation can occur. Understanding the fate of nitrogen in Stony Brook Harbor requires knowing the volume of groundwater entering the bay as well as the amount of denitrification, in the context of the hydrogeological framework. This is achieved by combining electrical resistivity survey, water sampling in piezometers, point conductivity and seepage measurements. A Trident probe inserted 60 cm deep into the sediments allows measuring the conductivity and temperature of the sediments and the overlying seawater. In spring 2011, five Trident transects spreading across the head of the harbor were used as a preliminary study to reveal potential locations for SGD. Locations with significant difference between sediment and seawater temperature and/or conductivities were further investigated using an AGI SuperSting 8-channel receiver resistivity meter. Two ultrasonic seepage meters were deployed in May and July 2011 about 20 m below the low tide mark. Five piezometers were aligned parallel to one resistivity survey. Our resistivity data indicate superficial mixing in the intertidal zone. The freshwater extends quite far under the seafloor, above 67 meters after the low tide mark for one location. The freshwater/saltwater interface seems to be almost horizontal. The piezometer data agree relatively well with the resistivity data. The preliminary average seepage rates observed vary from 3 to 60 cm/d. The resistivity sections reveal the presence of a thin layer of high conductivity above the low tide mark. This matches the observation of a superficial

  4. Influence of constituent composition and texture on mineralogy and diagenesis of reef sediments

    SciTech Connect

    Boss, S.K.; Liddell, W.D.

    1985-01-01

    The close juxtaposition of Holocene and Pleistocene (120,000 y.b.p.) fringing reef deposits along the Jamaican north coast provides an excellent opportunity for the development of models relating original sediment mineralogies and textures to diagenetic alteration of carbonate sediments. Constituent composition controls initial mineralogies of the reef sediments. X-ray diffraction analyses of Holocene reef sediments reveal that aragonite is the most abundant carbonate phase (49-89%), followed by high-Mg calcite (8-46%) and low-Mg calcite (2-12%). Original sediment textural characteristics influence the diagenesis of these deposits. Analyses of Pleistocene back reef and shallow (5-8m) fore reef facies indicate that surface exposures of the back reef facies retain much of their original aragonite and high-Mg calcite, but surface exposures of the fore reef facies have undergone extreme diagenetic alteration to low-Mg calcite. Differential diagenesis of these deposits is attributed to variability initial sorting and permeability of back reef and fore reef sediments. Poorer sorting and reduced permeability of the back reef deposits has restricted fluid flow and concomitant conversion of metastable carbonate phases has been inhibited. Conversely, the better sorting and higher initial permeability of fore reef facies sediments has resulted in increased fluid migration, greater dissolution of aragonite and high-Mg calcite, and reprecipitation of low-Mg calcite in conjunction with the development of a 1m thick caliche cap.

  5. A geochemical and sedimentological perspective of the life cycle of Neapolis harbor (Naples, southern Italy)

    NASA Astrophysics Data System (ADS)

    Delile, H.; Goiran, J.-P.; Blichert-Toft, J.; Arnaud-Godet, F.; Romano, P.; Bravard, J.-P.

    2016-10-01

    Since the discovery of the ancient harbor of Naples in 2004 during construction work on an underground railway, geoarchaeological studies undertaken on the archaeological excavation have revealed the main stratigraphic and paleo-environmental levels of the harbor site near the Piazza Municipio. However, knowledge of the dynamics and paleo-environmental changes in the water column of the harbor, as well as the processes of transport and deposition of sediments that led to siltation and infilling of the harbor basin, has been lacking due to the absence of high-resolution data. To fill these gaps, we have undertaken a three-dimensional study (longitudinal, transverse and vertical) of the harbor deposits by carrying out geochemical and sedimentological analyses of four stratigraphic sections of the archaeological excavation. The results show that after a phase of relative calm during the first half of the 1st c. AD, siltation of the harbor progressed exponentially up to the 5th c. AD, when dredging operations were carried out to obtain a water level sufficient for the development of maritime and harbor activities. We attribute this acceleration of siltation to a combination of climatic, anthropic and volcanic factors. Volcanic activity was responsible for a high-energy, tsunami-type event during the eruption of Vesuvius in 79 AD. From the 5th c. AD onwards, the harbor basin of Neapolis does not appear to have been functional as evidenced by its transformation into a lagoon following coastal progradation. The last stage of infilling was the development of a flood-dominated fan delta under the combined influences of climatic cooling in the Early Medieval Cool Period and agro-pastoral activities in the catchment area of the harbor. Several generations of paleo-channels, containing flash flood deposits, as well as sheet wash from sheet floods, are indicative of high environmental instability in this period.

  6. Influence of mangrove reforestation on heavy metal accumulation and speciation in intertidal sediments.

    PubMed

    Zhou, Yan-Wu; Zhao, Bo; Peng, Yi-Sheng; Chen, Gui-Zhu

    2010-08-01

    To investigate the influence of mangrove reforestation on heavy metal accumulation and speciation in intertidal sediments, core sediments from a restored mangrove forest and adjacent mud flat in Yifeng Estuary (southeastern China) were analyzed. The chemical speciation of heavy metals (Pb, Zn, Cu, Cr and Ni) was determined according to a sequential extraction procedure. Special attention was paid to the upper 20cm of sediment, in which metal accumulation was enhanced and speciation was obviously modified. Mangrove reforestation decreased the concentrations of all metals in the acid-soluble fraction and increased metal concentrations in the oxidizable fraction. Increased Pb, Zn and Cu concentrations and decreased Ni and Cr concentrations were observed in the reducible fraction. These results suggest that mangrove reforestation facilitated the accumulation of heavy metals in the upper sediment layers but decreased their bioavailability and mobility. Copyright 2010 Elsevier Ltd. All rights reserved.

  7. Sulfur containing sediments influenced wear of superheater tubes

    SciTech Connect

    Yoffe, P.

    1996-10-01

    The failed superheater tube was investigated at the point of failure and at a distance of 25 cm. At both of the cross sections two layers of sediment were detected. The external one contains Na2SO4 and Na3VO3 in concentration relation 6.4:1 approximately. The internal layer that situated on the tube surface consisted of V2O3 mainly (about 70%) and sodium pyrosulfates Na2SO3{center_dot}xSO3. The tube surface was covered with usual passive oxides such as Cr2O3, Fe2CrO4, and magnetite. In the failed section the last layer contained iron and chromium sulfides. Thinning of the wall was detected in both sections, but it was more evident in the failed section. Thermodynamic and kinetic estimations of the results were carried out. The following failure mechanism was proposed: (1) at 460 C the pyrosulfate dissociates with SO3 emanation, during SO3 interaction with steel both passive oxides and iron sulfide are produced simultaneously, sulfides damage the passive (protective) film; (2) in vicinity of partition the temperature increases and the structure of steel is changed, SO3 penetration along grain boundaries is possible, and it leads to embrittlement of the steel through sulfidization; (3) the embrittled layer is stripped off by falling ash deposit and collapsed passive film, thinning of the tube is accelerated at such a region. So, sulfur containing sediment accelerates the wear of the tube. This acceleration is strong especially in the vicinity of the boiler walls.

  8. Identifying the cause and source of sediment toxicity in an agriculture-influenced creek.

    PubMed

    Weston, Donald P; Zhang, Minghua; Lydy, Michael J

    2008-04-01

    Del Puerto Creek, an agriculturally influenced stream in northern California, USA, with a history of sediment toxicity, was used as a case study to determine the feasibility of using sediment toxicity testing and chemical analysis to identify the causative agent for the toxicity and its sources. Testing with the amphipod Hyalella azteca confirmed historical toxicity and identified a point along the creek at which there was an abrupt increase in sediment toxicity that persisted for at least 6 km downstream. Three recently developed whole sediment toxicity identification evaluation manipulations, temperature reduction, piperonyl butoxide addition, and esterase addition, were applied to sediment from one site and were suggestive of a pyrethroid as the cause for toxicity. Utilizing published median lethal concentration (LC50) values in a toxic unit analysis, the pyrethroid insecticide bifenthrin was identified as the primary contributor to toxicity in nearly all sites at which toxicity was observed, with occasional additional contributions from the pyrethroids lambda-cyhalothrin, esfenvalerate, and cyfluthrin. Most agricultural drains discharging to Del Puerto Creek contained bifenthrin in their sediments at concentrations near or above acutely toxic concentrations. However, only one drain contained sediments with bifenthrin concentrations approaching the concentrations measured in creek sediments. This fact, along with the proximity of that particular discharge to the location in the creek with the highest concentrations, suggested that one drain may be responsible for much of the toxicity and pyrethroid residues in creek sediments. The methods employed in this study are likely to be of considerable value in total maximum daily load efforts in Del Puerto Creek or other California surface water bodies known to have pyrethroid-related aquatic toxicity.

  9. Anthropogenic influence on sedimentation and intertidal mudflat change in San Pablo Bay, California: 1856-1983

    USGS Publications Warehouse

    Jaffe, B.E.; Smith, R.E.; Foxgrover, A.C.

    2007-01-01

    Analysis of a series of historical bathymetric surveys has revealed large changes in morphology and sedimentation from 1856 to 1983 in San Pablo Bay, California. In 1856, the morphology of the bay was complex, with a broad main channel, a major side channel connecting to the Petaluma River, and an ebb-tidal delta crossing shallow parts of the bay. In 1983, its morphology was simpler because all channels except the main channel had filled with sediment and erosion had planed the shallows creating a uniform gently sloping surface. The timing and patterns of geomorphic change and deposition and erosion of sediment were influenced by human activities that altered sediment delivery from rivers. From 1856 to 1887, high sediment delivery (14.1 ?? 106 m3/yr) to San Francisco Bay during the hydraulic gold-mining period in the Sierra Nevada resulted in net deposition of 259 ?? 14 ?? 106 m3 in San Pablo Bay. This rapid deposition filled channels and increased intertidal mudflat area by 60% (37.4 ?? 3.4 to 60.6 ?? 6.2 km2). From 1951 to 1983, 23 ?? 3 ?? 106 m3 of sediment was eroded from San Pablo Bay as sediment delivery from the Sacramento and San Joaquin Rivers decreased to 2.8 ?? 106 m3/yr because of damming of rivers, riverbank protection, and altered land use. Intertidal mudflat area in 1983 was 31.8 ?? 3.9 km2, similar to that in 1856. Intertidal mudflat distribution in 1983, however, was fairly uniform whereas most of the intertidal mudflats were in the western part of San Pablo Bay in 1856. Sediment delivery, through its affect on shallow parts of the bay, was determined to be a primary control on intertidal mudflat area. San Pablo Bay has been greatly affected by human activities and will likely continue to erode in the near term in response to a diminished sediment delivery from rivers. ?? 2007 Elsevier Ltd. All rights reserved.

  10. [Characteristics and influencing factors of phosphorus adsorption on sediment in Lake Taihu and Lake Hulun].

    PubMed

    Chuai, Xiao-Ming; Yang, Liu-Yan; Cheng, Shu-Bo; Chen, Xiao-Feng; Mu, Yun-Song

    2014-03-01

    Lake Taihu and Lake Hulun in southern and northern China were selected for the investigation of differences in the characteristics and influencing factors of phosphorus (P) adsorption on the sediments of these two lakes by laboratory simulation experiment. The results showed that: (1) The P adsorption capacity of sediment in Lake Taihu was much higher than that in Lake Hulun, and the maximum adsorption capability for the sediments in these two lakes was 1428.57 mg x kg(-1) and 56.81 mg x kg(-1), respectively; (2) Compared with the sediments in Lake Hulun, the particle diameters from sediments in Lake Taihu were much smaller, and their specific surface areas were much larger, so their P adsorption capacity were much higher; (3) The equilibrium adsorbed amounts in these two lakes were correlated with the total amounts of Al, Fe, Mn (P < 0.05) and significantly correlated to the contents of active Al, Fe, Si, Mn (P < 0.01). However, there was significant negative correlation between the equilibrium adsorbed amounts and total Si contents for the sediments in these two lakes (P < 0.01); (4) The P adsorption capacity decreased as pH values in the overlying water increased, and the increase of pH values affected the adsorption behavior of phosphorus on the sediments in Lake Taihu much more obviously. Therefore, the characteristics of sediments and the variations of pH values in the overlying water affected the adsorption behavior of P on sediments in lake water body.

  11. Influence of Physiologic Folate Deficiency on Human Papillomavirus Type 16 (HPV16)-harboring Human Keratinocytes in Vitro and in Vivo*

    PubMed Central

    Xiao, Suhong; Tang, Ying-Sheng; Khan, Rehana A.; Zhang, Yonghua; Kusumanchi, Praveen; Stabler, Sally P.; Jayaram, Hiremagalur N.; Antony, Aśok C.

    2012-01-01

    Although HPV16 transforms infected epithelial tissues to cancer in the presence of several co-factors, there is insufficient molecular evidence that poor nutrition has any such role. Because physiological folate deficiency led to the intracellular homocysteinylation of heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) and activated a nutrition-sensitive (homocysteine-responsive) posttranscriptional RNA operon that included interaction with HPV16 L2 mRNA, we investigated the functional consequences of folate deficiency on HPV16 in immortalized HPV16-harboring human (BC-1-Ep/SL) keratinocytes and HPV16-organotypic rafts. Although homocysteinylated hnRNP-E1 interacted with HPV16 L2 mRNA cis-element, it also specifically bound another HPV16 57-nucleotide poly(U)-rich cis-element in the early polyadenylation element (upstream of L2̂L1 genes) with greater affinity. Together, these interactions led to a profound reduction of both L1 and L2 mRNA and proteins without effects on HPV16 E6 and E7 in vitro, and in cultured keratinocyte monolayers and HPV16-low folate-organotypic rafts developed in physiological low folate medium. In addition, HPV16-low folate-organotypic rafts contained fewer HPV16 viral particles, a similar HPV16 DNA viral load, and a much greater extent of integration of HPV16 DNA into genomic DNA when compared with HPV16-high folate-organotypic rafts. Subcutaneous implantation of 18-day old HPV16-low folate-organotypic rafts into folate-replete immunodeficient mice transformed this benign keratinocyte-derived raft tissue into an aggressive HPV16-induced cancer within 12 weeks. Collectively, these studies establish a likely molecular linkage between poor folate nutrition and HPV16 and predict that nutritional folate and/or vitamin-B12 deficiency, which are both common worldwide, will alter the natural history of HPV16 infections and also warrant serious consideration as reversible co-factors in oncogenic transformation of HPV16-infected tissues to cancer

  12. Influence of physiologic folate deficiency on human papillomavirus type 16 (HPV16)-harboring human keratinocytes in vitro and in vivo.

    PubMed

    Xiao, Suhong; Tang, Ying-Sheng; Khan, Rehana A; Zhang, Yonghua; Kusumanchi, Praveen; Stabler, Sally P; Jayaram, Hiremagalur N; Antony, Asok C

    2012-04-06

    Although HPV16 transforms infected epithelial tissues to cancer in the presence of several co-factors, there is insufficient molecular evidence that poor nutrition has any such role. Because physiological folate deficiency led to the intracellular homocysteinylation of heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) and activated a nutrition-sensitive (homocysteine-responsive) posttranscriptional RNA operon that included interaction with HPV16 L2 mRNA, we investigated the functional consequences of folate deficiency on HPV16 in immortalized HPV16-harboring human (BC-1-Ep/SL) keratinocytes and HPV16-organotypic rafts. Although homocysteinylated hnRNP-E1 interacted with HPV16 L2 mRNA cis-element, it also specifically bound another HPV16 57-nucleotide poly(U)-rich cis-element in the early polyadenylation element (upstream of L2L1 genes) with greater affinity. Together, these interactions led to a profound reduction of both L1 and L2 mRNA and proteins without effects on HPV16 E6 and E7 in vitro, and in cultured keratinocyte monolayers and HPV16-low folate-organotypic rafts developed in physiological low folate medium. In addition, HPV16-low folate-organotypic rafts contained fewer HPV16 viral particles, a similar HPV16 DNA viral load, and a much greater extent of integration of HPV16 DNA into genomic DNA when compared with HPV16-high folate-organotypic rafts. Subcutaneous implantation of 18-day old HPV16-low folate-organotypic rafts into folate-replete immunodeficient mice transformed this benign keratinocyte-derived raft tissue into an aggressive HPV16-induced cancer within 12 weeks. Collectively, these studies establish a likely molecular linkage between poor folate nutrition and HPV16 and predict that nutritional folate and/or vitamin-B(12) deficiency, which are both common worldwide, will alter the natural history of HPV16 infections and also warrant serious consideration as reversible co-factors in oncogenic transformation of HPV16-infected tissues to cancer.

  13. INFLUENCE OF SEDIMENT SUPPLY, LITHOLOGY, AND WOOD DEBRIS ON THE DISTRIBUTION OF BEDROCK AND ALLUVIAL CHANNELS

    EPA Science Inventory

    Field surveys in the Willapa River basin, Washington State, indicate that the drainage area?channel slope threshold describing the distribution of bedrock and alluvial channels is influenced by the underlying lithology and that local variations in sediment supply can overwhelm ba...

  14. INFLUENCE OF SEDIMENT SUPPLY, LITHOLOGY, AND WOOD DEBRIS ON THE DISTRIBUTION OF BEDROCK AND ALLUVIAL CHANNELS

    EPA Science Inventory

    Field surveys in the Willapa River basin, Washington State, indicate that the drainage area?channel slope threshold describing the distribution of bedrock and alluvial channels is influenced by the underlying lithology and that local variations in sediment supply can overwhelm ba...

  15. Sediment deposition from forest roads at stream crossings as influenced by road characteristics

    Treesearch

    A.J. Lang; W.M. Aust; M.C. Bolding; K.J. McGuire

    2015-01-01

    Recent controversies associated with ditched forest roads and stream crossings in the Pacific Northwest have focused national attention on sediment production and best management practices (BMPs) at stream crossings. Few studies have quantified soil erosion rates at stream crossings as influenced by road characteristics and compared them to modeled rates. Soil erosion...

  16. The influence of biogenic stabilisation on the stability and transport of cohesive and mixed sediments.

    NASA Astrophysics Data System (ADS)

    Hope, Julie; Aspden, Rebecca; Baas, Jaco; Paterson, David

    2015-04-01

    Recent decades have highlighted key interactions occurring at the sediment-water interface between the physical, chemical and biological properties of intertidal systems. With increased storm events and impending sea level rise, understanding these interactions is increasingly important. One key interaction, which has to be considered when investigating sediment erosion and transport, is the effect that microbial algae and their secreted extracellular polymeric substances (EPS) have on the erosion resistance cohesive and mixed sediment. Despite evidence that biofilms can increasing the stability of fine sediments by up to 10 times, sediment transport predictions have still been largely based on abiotic models (e,g Yallin parameter and Shield's model). The manner in which biological processes affect the behaviour of intertidal sediment remains a contentious topic in several disciplines, largely due to a lack of knowledge and difficulty in adequately representing these variable effects in a predictive model. The mechanical protection provided by biofilms and the associated EPS has been investigated as part of a long-term field campaign in the Eden estuary, Scotland. This study incorporates the measurement of multiple physical (including particle size distribution (PSD), water content, flow velocity, salinity,) and biochemical (EPS content and microbial biomass) properties and the relative influence of these properties on the erosion and transport of various sediment types. Measurements were collected both within and between seasons and over tidal cycles to account for a multitude of environmental variables such as temperature, tidal input, flow velocities, weather etc. Intertidal sites were selected within the upper estuary encompassing varied bed structure (particle size distributions) within a relatively limited spatial scale to minimise the effects of salinity gradients and fluvial input across the sites. Results indicate EPS content was significantly different

  17. The influence of extraction procedure on ion concentrations in sediment pore water

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.; Jackson, B.P.

    1998-01-01

    Sediment pore water has the potential to yield important information on sediment quality, but the influence of isolation procedures on the chemistry and toxicity are not completely known and consensus on methods used for the isolation from sediment has not been reached. To provide additional insight into the influence of collection procedures on pore water chemistry, anion (filtered only) and cation concentrations were measured in filtered and unfiltered pore water isolated from four sediments using three different procedures: dialysis, centrifugation and vacuum. Peepers were constructed using 24-cell culture plates and cellulose membranes, and vacuum extractors consisted of fused-glass air stones attached with airline tubing to 60cc syringes. Centrifugation was accomplished at two speeds (2,500 and 10,000 x g) for 30 min in a refrigerated centrifuge maintained at 4?C. Only minor differences in chemical characteristics and cation and anion concentrations were found among the different collecting methods with differences being sediment specific. Filtering of the pore water did not appreciably reduce major cation concentrations, but trace metals (Cu and Pb) were markedly reduced. Although the extraction methods evaluated produced pore waters of similar chemistries, the vacuum extractor provided the following advantages over the other methods: (1) ease of extraction, (2) volumes of pore water isolated, (3) minimal preparation time and (4) least time required for extraction of pore water from multiple samples at one time.

  18. Ambient Noise Measurements in and Around the Gulfport Mississippi Harbor and its Potential Influence on Marine Mammals

    DTIC Science & Technology

    2007-06-21

    relating to navigation, migration, reproduction , and feeding, (c) influences leading to stranding, and (d) physiological impairment of their hearing...into shallow water areas for birthing, where shark predation of juvenile dolphin is more restricted, and deals with the issue of noise interference...34Temporary shift in masked hearing thresholds of bottlenose dolphins, Tursiops truncatus, and white whales , Delphinapterus leucas, after

  19. Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans.

    PubMed

    Franzen, Julia; Menzel, Ralph; Höss, Sebastian; Claus, Evelyn; Steinberg, Christian E W

    2012-03-01

    River water quality is strongly influenced by their sediments and their associated pollutants. To assess the toxic potential of sediments, sediment toxicity tests require reliable control sediments, potentially including formulated control sediments as one major option. Although some standardization has been carried out, one critical issue still remains the quality of sediment organic matter (SOM). Organic carbon not only binds hydrophobic contaminants, but may be a source of mild toxicity, even if the SOM is essentially uncontaminated. We tested two different sources of organic carbon and the mixture of both (Sphagnum peat (P) and one commercial humic substances preparation-HuminFeed(®), HF) in terms of life trait variables and expression profiles of selected life performance and stress genes of the nematode Caenorhabditis elegans. In synchronous cultures, gene expression profiling was done after 6 and 48 h, respectively. The uncontaminated Sphagnum P reduced growth, but increased numbers of offspring, whereas HF did not significantly alter life trait variables. The 6 h expression profile showed most of the studied stress genes repressed, except for slight to strong induction in cyp-35B1 (all exposures), gst-38 (only mixture), and small hsp-16 genes (all exposures). After 48 h, the expression of almost all studied genes increased, particularly genes coding for antioxidative defense, multiple xenobiotic resistance, vitellogenin-like proteins, and genes regulating lifespan. Overall, even essentially uncontaminated SOM may induce several modes of action on the molecular level in C. elegans which may lead to false results if testing synthetic xenobiotics. This contribution is a plea for a strict standardization of the SOM quality in formulated sediments and to check for corresponding effects in other model sediment organisms, especially if using molecular toxicity endpoints.

  20. Influence of oxic/anoxic condition on sorption behavior of PFOS in sediment.

    PubMed

    Ololade, Isaac Ayodele; Zhou, Qin; Pan, Gang

    2016-05-01

    Sediment components and redox properties change with oxic/anoxic condition, which affect the environmental transport of perfluorooctane sulfonate (PFOS). Herein, the influence of oxic/anoxic condition on the variation of redox and residual components of sediments, where organic matter, iron and manganese oxides are separated from the original sediment collected from Lake Taihu, China, are investigated. Meanwhile, the distinguishing sorption behaviors of PFOS on various residual sediments under oxic and anoxic condition are studied. Sediment after extracting iron and manganese (S-FeMn), which possessed the highest organic carbon (0.99%), had the highest affinity for PFOS under oxic condition. However, anoxic environment resulted in an increase of the pH, dissolving of organic carbon and de-protonation of S-FeMn, which caused the lower sorption capacity of PFOS on S-FeMn. Sediment after extracting manganese (S-Mn) had the higher sorption ability in anoxic environment because the Fe(2+) from S-Mn provided more effective electrostatic sites for anionic PFOS. When the environment changed to oxic condition, the iron existed as trivalent form in S-Mn, which resulted in a block of effective sorption site and reduced the sorption amounts of PFOS. The higher percentage of manganese oxides restrained the sorption of PFOS. Hence, whether or not oxic/anoxic condition promoted the PFOS sorption depended on both the percentage and form of various components in the sediment. The study generated further insight into the environmental transport of PFOS in the sediments with different properties and the wetland system, where oxic/anoxic subsurface flow was constructed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Assessing natural and anthropogenic influences on water discharge and sediment load in the Yangtze River, China.

    PubMed

    Zhao, Yifei; Zou, Xinqing; Liu, Qing; Yao, Yulong; Li, Yali; Wu, Xiaowei; Wang, Chenglong; Yu, Wenwen; Wang, Teng

    2017-12-31

    The water discharge and sediment load of rivers are changing substantially under the impacts of climate change and human activities, becoming a hot issue in hydro-environmental research. In this study, the water discharge and sediment load in the mainstream and seven tributaries of the Yangtze River were investigated by using long-term hydro-meteorological data from 1953 to 2013. The non-parametric Mann-Kendall test and double mass curve (DMC) were used to detect trends and abrupt change-points in water discharge and sediment load and to quantify the effects of climate change and human activities on water discharge and sediment load. The results are as follows: (1) the water discharge showed a non-significant decreasing trend at most stations except Hukou station. Among these, water discharge at Dongting Lake and the Min River basin shows a significant decreasing trend with average rates of -13.93×10(8)m(3)/year and -1.8×10(8)m(3)/year (P<0.05), respectively. However, the sediment load exhibited a significant decreasing trend in all tributaries of the Yangtze River. (2) No significant abrupt change-points were detected in the time series of water discharge for all hydrological stations. In contrast, significant abrupt change-points were detected in sediment load, most of these changes appeared in the late 1980s. (3) The water discharge was mainly influenced by precipitation in the Yangtze River basin, whereas sediment load was mainly affected by climate change and human activities; the relative contribution ratios of human activities were above 70% for the Yangtze River. (4) The decrease of sediment load has directly impacted the lower Yangtze River and the delta region. These results will provide a reference for better resource management in the Yangtze River Basin. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Influence of vegetation on spatial patterns of sediment deposition in deltaic islands during flood

    NASA Astrophysics Data System (ADS)

    Nardin, W.; Edmonds, D. A.; Fagherazzi, S.

    2016-07-01

    River deltas are shaped by the interaction between flow and sediment transport. This morphodynamic interaction is potentially affected by freshwater marsh vegetation (e.g. Sagittaria spp.and Typha spp. in the Mississippi delta, USA) on the exposed surfaces of emergent deltaic islands. The vulnerability of deltaic islands is a result of external forces like large storms, sea level rise, and trapping of sediment in upstream reservoirs. These factors can strongly determine the evolution of the deltaic system by influencing the coupling between vegetation dynamics and morphology. In the last few years, models have been developed to describe the dynamics of salt marsh geomorphology coupled with vegetation growth while the effect of freshwater vegetation on deltaic islands and marshes remains unexplored. Here we use a numerical flow and sediment transport model to determine how vegetation affects the spatial distribution of sediment transport and deposition on deltaic surfaces during flood. Our modeling results show that, for an intermediate value of relative vegetation height and density, sedimentation rate increases at the head of the delta. On the other hand, large values of relative vegetation height and density promote more sedimentation at the delta shoreline. A logical extension of our results is that over time intermediate values of relative vegetation height and density will create a steeper-sloped delta due to sediment trapping at the delta head, whereas relatively taller vegetation will create a larger, but flatter delta due to sediment deposition at the shoreline. This suggests intermediate relative vegetation height and density may create more resilient deltas with higher average elevations.

  3. Examining Reservoir Influences on Fluvial Sediment Supply to Estuaries and Coastal Oceans with Sediment Geochronologies: Example from Conowingo Reservoir (Upper Chesapeake Bay, USA)

    NASA Astrophysics Data System (ADS)

    Palinkas, C. M.; Russ, E.

    2016-12-01

    The flux of fluvial sediment to estuaries and coastal oceans is often interrupted by natural and anthropogenic influences. Here, we focus on river dams, which alter the connection between rivers and their receiving basins via sediment sequestration in their reservoirs. Sediments are effectively trapped until river discharge is high enough to create flow velocities capable of resuspending sediment. Sediment resuspension often varies within the reservoir, driven by morphological features such as channels and islands. Thus, sediment residence times in the reservoir are often highly variable in space and time. This study focuses on reading the sedimentary record in one such system - the reservoir upstream of Conowingo Dam, built in the late 1920s and the last and largest dam on the Susquehanna River (Maryland, USA) before it enters Chesapeake Bay. This study establishes geochronologies of reservoir sedimentation on seasonal to decadal time scales with a variety of techniques (e.g., natural and anthropogenic radioisotopes (7Be, 210Pb, 137Cs), coal from mining in the watershed) to interpret observed down-core sedimentary structures and characteristics (grain size, organic content). These observations reveal spatial and temporal patterns of sediment deposition and/or erosion. Placed within the broader context of reservoir geomorphology, these results can improve predictions of sediment supply to downstream environments, in this case Chesapeake Bay, where it can impact water quality and/or benthic organisms.

  4. Alcaligenes aquatilis sp. nov., a novel bacterium from sediments of the Weser Estuary, Germany, and a salt marsh on Shem Creek in Charleston Harbor, USA.

    PubMed

    Van Trappen, Stefanie; Tan, Tjhing-Lok; Samyn, Emly; Vandamme, Peter

    2005-11-01

    Four nitrite-dissimilating strains, isolated from Weser Estuary sediments, were investigated using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belong to the 'Betaproteobacteria' and are related to the genus Alcaligenes. The highest level of sequence similarity (100 %) was found with strain M3A (=ATCC 700596), a dimethyl sulfide-producing marine isolate that was included in this study. DNA-DNA hybridizations between the five strains and related Alcaligenes faecalis strains confirmed that the former belong to a single and novel species within the genus Alcaligenes. The isolates are Gram-negative, motile, rod-shaped cells with a DNA G+C content of about 56 mol%. The whole-cell fatty acid profiles of the isolates were very similar and included C(16 : 0), C(17 : 0) cyclo, C(18 : 1)omega7c, summed feature 2 (comprising any combination of C(12 : 0) aldehyde, an unknown fatty acid of equivalent chain length 10.928, C(16 : 1) iso I and C(14 : 0) 3-OH) and summed feature 3 (C(15 : 0) iso 2-OH and/or C(16 : 1)omega7c) as the major fatty acid components. On the basis of their phylogenetic, genomic and phenotypic properties, the five novel strains can be assigned to the genus Alcaligenes as a novel species, for which the name Alcaligenes aquatilis sp. nov. is proposed. The type strain is LMG 22996T (=CCUG 50924T).

  5. New Bedford Harbor Long Term Monitoring Program

    EPA Science Inventory

    New Bedford Harbor (NBH), located in southeastern Massachusetts, was designated as a Superfund site in 1983 due to unacceptably high levels of sediment contamination by polychlorinated biphenyls (PCBs). Based on human health and environmental concerns, the decision was made to d...

  6. New Bedford Harbor Long Term Monitoring Program

    EPA Science Inventory

    New Bedford Harbor (NBH), located in southeastern Massachusetts, was designated as a Superfund site in 1983 due to unacceptably high levels of sediment contamination by polychlorinated biphenyls (PCBs). Based on human health and environmental concerns, the decision was made to d...

  7. Quantifying the influence of sediment source area sampling on detrital thermochronometer data

    NASA Astrophysics Data System (ADS)

    Whipp, D. M., Jr.; Ehlers, T. A.; Coutand, I.; Bookhagen, B.

    2014-12-01

    Detrital thermochronology offers a unique advantage over traditional bedrock thermochronology because of its sensitivity to sediment production and transportation to sample sites. In mountainous regions, modern fluvial sediment is often collected and dated to determine the past (105 to >107 year) exhumation history of the upstream drainage area. Though potentially powerful, the interpretation of detrital thermochronometer data derived from modern fluvial sediment is challenging because of spatial and temporal variations in sediment production and transport, and target mineral concentrations. Thermochronometer age prediction models provide a quantitative basis for data interpretation, but it can be difficult to separate variations in catchment bedrock ages from the effects of variable basin denudation and sediment transport. We present two examples of quantitative data interpretation using detrital thermochronometer data from the Himalaya, focusing on the influence of spatial and temporal variations in basin denudation on predicted age distributions. We combine age predictions from the 3D thermokinematic numerical model Pecube with simple models for sediment sampling in the upstream drainage basin area to assess the influence of variations in sediment production by different geomorphic processes or scaled by topographic metrics. We first consider a small catchment from the central Himalaya where bedrock landsliding appears to have affected the observed muscovite 40Ar/39Ar age distributions. Using a simple model of random landsliding with a power-law landslide frequency-area relationship we find that the sediment residence time in the catchment has a major influence on predicted age distributions. In the second case, we compare observed detrital apatite fission-track age distributions from 16 catchments in the Bhutan Himalaya to ages predicted using Pecube and scaled by various topographic metrics. Preliminary results suggest that predicted age distributions scaled

  8. How are River Discharge - Suspended Sediment Relations Influenced by Watershed and Channel-Floodplain Morphology?

    NASA Astrophysics Data System (ADS)

    Vaughan, A. A.; Belmont, P.

    2015-12-01

    Erosion, transport and deposition of fine sediment (clay, silt and fine sand) influence the form and function of river systems. Excess suspended sediment degrades stream ecosystems and is implicated as a leading cause of water quality and aquatic life impairment. Consequently, understanding the factors that control fine sediment transport regimes is an interesting topic for basic science and one that has important management and policy implications. Fine sediment is mostly transported in suspension as a non-capacity load; transport rates are dependent on sediment supply in addition to a river's transport capacity. Many studies have investigated watershed-scale topographic, hydrologic, climatic, and land use influences on fine sediment erosion and transport regimes. Several recent studies in a wide range of landscapes have demonstrated that the majority of suspended sediment may be sourced from the near-channel environment; therefore, near-channel morphological characteristics may provide better predictive power compared to watershed averages. This study analyzes recent total suspended solids (TSS) data from 45 gages on 35 separate rivers. The rivers span the state of Minnesota, draining basins ranging from 33 km2 to 68100 km2 with distinct settings in terms of topography, land cover, hydrology and geologic history. We generate rating curves of the form TSS = aQb, where Q is normalized discharge and a and b are parameters that describe the shape of the relations. Values of a range from 4 to 138 mg/L; b values range from -0.53 to 1.86. We use high resolution lidar topography data to characterize the near-channel environment upstream of gages. In addition to commonly studied metrics describing the topographic, climatic/hydrologic and land use setting of the basin, we extract near-channel morphometrics that we hypothesize to influence fine sediment generation and transport: the difference in height of banks/bluffs (a measure of the amount of material available to be

  9. Factors influencing adsorption and desorption of trimethoprim on marine sediments: mechanisms and kinetics.

    PubMed

    Li, Jia; Zhang, Hua

    2017-08-05

    Adsorption-desorption behavior of ionic antibiotics in natural aquatic environment is complex, especially in coastal or estuary area where influencing factors such as pH and salinity usually varied in a wide range. In this study, batch-type and stirred flow chamber (SFC) experiments were carried out to simulate the sorption-desorption behavior of trimethoprim (TMP) in seawater-sediment system. Equilibrium and kinetic modeling were carried out to determine the rate and extent of TMP sorption on two marine sediments with different properties. Sediment BHB (K d , 6.40 L kg(-1)) has a greater sorption capacity compared with sediment LZB (K d , 3.40 L kg(-1)), which is related to the higher content of organic carbon and clay of sediment BHB. Adsorption of TMP varied in the pH range of 6.9 to 8.1 with maximum adsorption at pH 7.4. Increasing salinity and presence of phosphate and nitrate led to decreased TMP sorption. Attenuated total reflection Fourier transform infrared (ATR-FTIR) analysis demonstrated the formation of hydrogen bond between TMP and marine sediments. Adsorption of TMP on marine sediments was a non-equilibrium process that can be described with second-order kinetic model. Our analysis suggested that chemical non-equilibrium was the rate controlling process and intraparticle diffusion was also involved in TMP adsorption. A moderate desorption percentage (16.4-22.8% for LZB and 32.5-42.0%for BHB) was observed. Overall, the results showed that environmental factors and time-dependent processes need to be considered in modeling the fate and transport of TMP in coastal/estuarine waters.

  10. Influence of sediment contaminated with untreated pulp and paper mill effluent on winter flounder, Pleuronectes americanus.

    PubMed

    Khan, R A

    2010-01-01

    This study was conducted to ascertain the influence of sediment contaminated with pulp and paper mill effluent in a fjord on winter flounder, Pleuronectes americanus, based on a laboratory study. Flounder, captured from a pristine site, were exposed in a flow-through system for 16 weeks to sediment collected at 2, 5, 7, and 10 km from the outfall. A group of controls was placed in uncontaminated sediment. Mortality occurred almost exclusively in fish exposed to sediment taken from 2 km than from more distant sites. Additionally, the condition factor was lower, the liver was enlarged, and toxicopathic lesions in the liver and spleen were significantly greater in fish submerged in the sediment than in fish from the more distant locations or the controls. Two ectoparasites including a ciliate, Trichodina jadranica, and a monogenean, Gyrodactylus pleuronecti, were observed only in the control group, while a digenean in the digestive tract, Steringophorus furciger, was more abundant in fish exposed to sediment from sites more distant from the outfall and the controls than at 2 km. Comparison of these results with data from a previous gradient field study on biological variables in winter flounder, captured at 2, 5, 7, and 10 km down-current from the outfall, revealed an enlarged liver that was associated with elevated levels of detoxification of hepatic enzymes and prevalence of toxicopathic lesions in both the liver and the spleen; these were significantly greater in samples taken nearest to the outfall from the mill than at more distant sites. Moreover, two metazoan parasites, S. furciger (Digenea) and Echinorhynchus gadi (Acanthocephala), in the digestive were more abundant in samples taken at farther locations and also from the reference sites. These results, based on a laboratory study, are in agreement with previous observations that winter flounder exposed to sediment at the site nearest to the outfall, where high concentrations of toxic contaminants persisted

  11. Influence of deglaciation on microbial communities in marine sediments off the coast of Svalbard, Arctic Circle.

    PubMed

    Park, Soo-Je; Park, Byoung-Joon; Jung, Man-Young; Kim, So-Jeong; Chae, Jong-Chan; Roh, Yul; Forwick, Matthias; Yoon, Ho-Il; Rhee, Sung-Keun

    2011-10-01

    Increases in global temperatures have been shown to enhance glacier melting in the Arctic region. Here, we have evaluated the effects of meltwater runoff on the microbial communities of coastal marine sediment located along a transect of Temelfjorden, in Svalbard. As close to the glacier front, the sediment properties were clearly influenced by deglaciation. Denaturing gradient gel electrophoresis profiles showed that the sediment microbial communities of the stations of glacier front (stations 188-178) were distinguishable from that of outer fjord region (station 176). Canonical correspondence analysis indicated that total carbon and calcium carbonate in sediment and chlorophyll a in bottom water were key factors driving the change of microbial communities. Analysis of 16S rRNA gene clone libraries suggested that microbial diversity was higher within the glacier-proximal zone (station 188) directly affected by the runoffs than in the outer fjord region. While the crenarchaeotal group I.1a dominated at station 176 (62%), Marine Benthic Group-B and other Crenarchaeota groups were proportionally abundant. With regard to the bacterial community, alpha-Proteobacteria and Flavobacteria lineages prevailed (60%) at station 188, whereas delta-Proteobacteria (largely sulfate-reducers) predominated (32%) at station 176. Considering no clone sequences related to sulfate-reducers, station 188 may be more oxic compared to station 176. The distance-wise compositional variation in the microbial communities is attributable to their adaptations to the sediment environments which are differentially affected by melting glaciers.

  12. Growth and decline of shoreline industry in Sydney estuary (Australia) and influence on adjacent estuarine sediments.

    PubMed

    Birch, G F; Lean, J; Gunns, T

    2015-06-01

    Sydney estuary (Australia), like many urbanised waterways, is degraded due to an extended history of anthropogenic activity. Two major sources of contamination to this estuary are discharge by former shoreline industries and historic and contemporary catchment stormwater. The objectives of the present study were to document changes in shoreline land use from European settlement to the present day and determine the influence of this trend on the metal content of adjacent estuarine sediments. Temporal analysis of land use for seven time horizons between 1788 and 2010 showed rapid expansion of industry along much of the Sydney estuary foreshore soon after European settlement due to the benefits of easy and inexpensive access and readily available water for cooling and power. Shoreline industry attained maximum development in 1978 (32-km length) and declined rapidly to the present-day (9-km length) through redevelopment of industrial sites into medium- to high-density, high-value residential housing. Cores taken adjacent to 11 long-term industrial sites showed that past industrial practices contributed significantly to contamination of estuarine sediment. Subsurface metal concentrations were up to 35 times that of present-day surface sediment and over 100 times greater than natural background concentrations. Sedimentation rates for areas adjacent to shoreline industry were between 0.6 and 2.5 cm/year, and relaxation times were estimated at 50 to 100 years. Natural relaxation and non-disturbance of sediments may be the best management practice in most locations.

  13. Temperature and Cyanobacterial Bloom Biomass Influence Phosphorous Cycling in Eutrophic Lake Sediments

    PubMed Central

    Chen, Mo; Ye, Tian-Ran; Krumholz, Lee R.; Jiang, He-Long

    2014-01-01

    Cyanobacterial blooms frequently occur in freshwater lakes, subsequently, substantial amounts of decaying cyanobacterial bloom biomass (CBB) settles onto the lake sediments where anaerobic mineralization reactions prevail. Coupled Fe/S cycling processes can influence the mobilization of phosphorus (P) in sediments, with high releases often resulting in eutrophication. To better understand eutrophication in Lake Taihu (PRC), we investigated the effects of CBB and temperature on phosphorus cycling in lake sediments. Results indicated that added CBB not only enhanced sedimentary iron reduction, but also resulted in a change from net sulfur oxidation to sulfate reduction, which jointly resulted in a spike of soluble Fe(II) and the formation of FeS/FeS2. Phosphate release was also enhanced with CBB amendment along with increases in reduced sulfur. Further release of phosphate was associated with increases in incubation temperature. In addition, CBB amendment resulted in a shift in P from the Fe-adsorbed P and the relatively unreactive Residual-P pools to the more reactive Al-adsorbed P, Ca-bound P and organic-P pools. Phosphorus cycling rates increased on addition of CBB and were higher at elevated temperatures, resulting in increased phosphorus release from sediments. These findings suggest that settling of CBB into sediments will likely increase the extent of eutrophication in aquatic environments and these processes will be magnified at higher temperatures. PMID:24682039

  14. Magnetic properties of sediments from the Pangani River Basin, Tanzania: Influence of lithology and particle size

    NASA Astrophysics Data System (ADS)

    Mzuza, Maureen Kapute; Zhang, Weiguo; Kapute, Fanuel; Selemani, Juma R.

    2017-08-01

    Use of magnetic properties in tracing sediment source in river systems is valuable for proper management of soil erosion and dam siltation. This study investigated magnetic properties variation from the upstream down to the coast of the Pangani River Basin in Tanzania, East Africa. The influence of lithology and sedimentary sorting on magnetic properties from source to sink pathway has been discussed. Results show that lithology can explain the differences in magnetic properties among the tributaries in the upstream and in the lower reach of the main stream. Ferrimagnetic minerals mainly consist of magnetite and titanomagnetite, with the latter more abundant in the upstream tributary Kikuletwa River. Upstream sediments have higher ferrimagnetic mineral concentrations but coarser grain size than the mainstream sediments, especially the dam sediments. A decline in ferrimagnetic mineral concentration with fining grain size is also observed along the mainstream. Such a trend can be explained by hydrodynamic sorting effect, which is well documented elsewhere. This study demonstrates that lithology and sorting have strong effect on magnetic properties, which should be properly addressed when using magnetic method in assessing fluvial sediment source.

  15. Influence of oyster culture on biogeochemistry and bacterial community structure at the sediment-water interface.

    PubMed

    Azandégbé, Afi; Poly, Franck; Andrieux-Loyer, Françoise; Kérouel, Roger; Philippon, Xavier; Nicolas, Jean-Louis

    2012-10-01

    Bacterial community structure and some biogeochemical parameters were studied in the sediment of two Pacific oyster farming sites, Aber Benoît (AB) and Rivière d'Auray (RA) in Brittany (France), to examine the ecological impact of oysters and to evaluate the emission of sulfide and ammonia from sediment. At AB, the organic matter accumulated in the sediment beneath the oyster tables was rapidly mineralized, with strong fluxes of ammonia and sulfide that reached 1014 and 215 μmol m(-2) h(-1), respectively, in June 2007. At RA, the fluxes were about half as strong on average and better distributed through the year. The ammonia and sulfide concentrations in the overlying water never reached levels that would be toxic to oysters in either site, nor did hypoxia occur. Total culturable bacteria (TCB) varied greatly according to the temperature: from 1.6 × 10(4) to 9.4 × 10(7) cell g(-1) sediment. Inversely, the bacterial community structure remained surprising stable through the seasons, marginally influenced by the presence of oysters and by temperature. Bacterial communities appeared to be characteristic of the sites, with only one common phylotype, Vibrio aestuarianus, a potential oyster pathogen. These data refine the hypothesis of seawater toxicity to oysters because of ammonia and sulfide fluxes and show that the measured environmental factors had only a weak influence on bacterial community structure.

  16. Influence of dams on sediment continuity: A study case of a natural metallic contamination.

    PubMed

    Frémion, Franck; Bordas, François; Mourier, Brice; Lenain, Jean-François; Kestens, Tim; Courtin-Nomade, Alexandra

    2016-03-15

    Sediments play an important role on the quality of aquatic ecosystems, notably in the reservoir areas where they can either be a sink or a source of contaminants, depending on the management and hydrological conditions. The physicochemical properties of 25 surface sediments samples of a reservoir catchment (Vaussaire, Cantal, France) were studied. Results show a strong influence of dam presence, notably on the grain size and organic matter (OM) contents. The concentrations of trace metals and metalloids (As, Cd, Cr, Cu, Ni, Pb and Zn) were also measured and compared with worldwide reservoir concentrations and international sediment quality guideline levels in order to assess the intensity of the metallic contamination. Cr and Ni are the trace elements presenting the significantly highest values at the catchment scale. Enrichment Factors (EF), calculated using both local and national backgrounds, show that metals have mainly a natural origin, explaining especially the Cr and Ni values, linked with the composition of parental rocks. Unexpectedly, all the observed metal concentrations are lower in the reservoir than upstream and downstream, which might be related to the high fresh OM inputs in the reservoir, diluting the global metallic contamination. Multivariate statistical analyses, carried out in order to identify the relationship between the studied metals and sediment characteristics, tend to support this hypothesis, confirming the unusually low influence of such poorly-degraded OM on trace element accumulation in the reservoir.

  17. Heavy metals in sediments of Ganga River: up- and downstream urban influences

    NASA Astrophysics Data System (ADS)

    Pandey, Jitendra; Singh, Rachna

    2015-09-01

    Bottom sediment in a river often acts as a sink and indicator of changes in water column and magnitude of anthropogenic influences through air and watersheds. Heavy metal concentration in sediments of Ganga River was studied along a 37-km stretch to assess whether there is a significant difference between sites situated upstream and downstream of Varanasi urban core. Metal concentration increased consistently along the study gradient, indicating the influence of urban sources. Concentration in the river sediment was found highest for Fe followed by Mn, Zn, Cr, Cu, Ni, Pb, and Cd. Mann-Kendall trend analysis showed marked seasonality in the concentration with values being highest in summer and lowest in rainy season. Enrichment factor revealed severe enrichment of Cd and Pb at downstream sites, and principal component analysis segregated sites into four distinct groups indicating source relationships. Concentrations of Cd, Pb, Ni, Cu, and Cr did exceed WHO standards. The study has relevance designing control measures and action plans for reducing sediment contamination in anthropogenic impacted rivers.

  18. Heavy metals in sediments of Ganga River: up- and downstream urban influences

    NASA Astrophysics Data System (ADS)

    Pandey, Jitendra; Singh, Rachna

    2017-07-01

    Bottom sediment in a river often acts as a sink and indicator of changes in water column and magnitude of anthropogenic influences through air and watersheds. Heavy metal concentration in sediments of Ganga River was studied along a 37-km stretch to assess whether there is a significant difference between sites situated upstream and downstream of Varanasi urban core. Metal concentration increased consistently along the study gradient, indicating the influence of urban sources. Concentration in the river sediment was found highest for Fe followed by Mn, Zn, Cr, Cu, Ni, Pb, and Cd. Mann-Kendall trend analysis showed marked seasonality in the concentration with values being highest in summer and lowest in rainy season. Enrichment factor revealed severe enrichment of Cd and Pb at downstream sites, and principal component analysis segregated sites into four distinct groups indicating source relationships. Concentrations of Cd, Pb, Ni, Cu, and Cr did exceed WHO standards. The study has relevance designing control measures and action plans for reducing sediment contamination in anthropogenic impacted rivers.

  19. The influence of cave stream sediments on the transport behavior of karst springs

    NASA Astrophysics Data System (ADS)

    Wagner, T.; Winkler, G.; Woessner, W.; Birk, S.

    2012-04-01

    Spring response to recharge in karst systems is influenced by the complex distribution of the rock mass hydraulic properties, fracture systems, and the presence of conduits. In addition the exchange of karst water with unconsolidated sediments in conduits may also further influence spring responses. To evaluate the effects of cave streams and sediments on solute transport in karst systems a small scale tracer experiment using fluorescein as an artificial tracer and water temperature as a natural tracer was conducted within the hyporheic zone of the active cave stream Schmelzbach. This interior stream drains parts of the Lurbach Karst System (Semriach-Peggau, Styria, Austria). The main goal of the experiment was to investigate if measurable cave stream hyporheic exchange (with the stream bottom sediments) occurs and the degree to which this process alters the transport of conservative tracers. One hundred meters downstream of the tracer injection point three cross sections of monitoring wells (9 in total along a distance of approximately 25 m) were constructed and fitted with two vertically isolated activated charcoal bags, 10 cm and 30 cm below the streambed surface. PVC monitoring wells were installed along the three cross sections using hand driven steel pipes as a temporary casing. In two of these wells temperature sensors were placed at different depths within the saturated bed sediment to investigate how post tracer test stream flood events impacted the timing and rate of stream water penetration into the bed sediments. The tracer breakthrough curve was measured with a fluorimeter located 100 m from the injection point. The results show a sharp peak and a modest tailing of the breakthrough. A one-dimensional advection dispersion model that accounts for mass transfer and storage of tracer in immobile fluid zones such as pools or sediments provides a good fit to the measured breakthrough curve. The model results suggest that immobile fluid zones amount to 40% of

  20. The influence of saltmarsh restoration on sediment dynamics and the potential impact on carbon sequestration

    NASA Astrophysics Data System (ADS)

    Taylor, Benjamin; Paterson, David

    2017-04-01

    Coastal wetland ecosystems can act as large-capacity carbon sinks, providing a valuable climate change mitigation function. Globally, saltmarshes are estimated to accumulate an average of 244.7g C m-2 yr-1 (Ouyang & Lee 2014). Saltmarsh areas have experienced rapid loss in the recent past of approximately 1-2% per year (Duarte et al. 2008). Efforts to restore these areas could result in additional carbon storage due to extended vegetation cover and altered burial due to changing sediment dynamics. The influence of restoration through transplantation on sediment dynamics within a small estuary on the east coast of Scotland was assessed. Restoration efforts have been implemented since the early 2000s providing examples of old established sites ("old", >10years), young recently planted sites ("young", <5years), and 'business-as-usual' mudflats and natural marsh areas. In each of these area types seasonal data of sediment deposition and settlement were collected and sediment accretion rates measured. Deposition and settlement samples were taken four times a season, provided total sediment weight and organic content information. Elevation changes were measured once per season, quantifying sediment accretion rates. All data were collected between summer 2015 and spring 2016. Data suggest a positive correlation between sediment settlement and deposition quantities (dry weight) across the estuary (r2=0.64), with restored areas displaying a slightly stronger relationship (old r2=0.67, young r2=0.68) compared to natural marsh and mudflats (r2=0.54 and 0.59 respectively). Suggesting restored areas which are developing or expanding are retaining more from the potential sediment load in the water column. However average amounts of actual deposited material are significantly greater in mudflat and young areas with old and natural areas significantly lower; potentially as a result of those being of a lower elevation. Nevertheless, percentage organic matter content of deposited

  1. Sediment compaction rates and subsidence in deltaic plains: Numerical constraints and stratigraphic influences

    USGS Publications Warehouse

    Meckel, T.A.; ten Brink, U.S.; Williams, S.J.

    2007-01-01

    Natural sediment compaction in deltaic plains influences subsidence rates and the evolution of deltaic morphology. Determining compaction rates requires detailed knowledge of subsurface geotechnical properties and depositional history, neither of which is often readily available. To overcome this lack of knowledge, we numerically forward model the incremental sedimentation and compaction of stochastically generated stratigraphies with geotechnical properties typical of modern depositional environments in the Mississippi River delta plain. Using a Monte Carlo approach, the range of probable compaction rates for stratigraphies with compacted thicknesses −1. The fastest compacting stratigraphies are composed primarily of peat and bar sand, whereas the slowest compacting stratigraphies are composed of prodelta mud and natural levee deposits. These results suggest that compaction rates can significantly influence vertical and lateral stratigraphic trends during deltaic evolution.

  2. Anthropogenic influence on sedimentation and intertidal mudflat change in San Pablo Bay, California: 1856 1983

    NASA Astrophysics Data System (ADS)

    Jaffe, Bruce E.; Smith, Richard E.; Foxgrover, Amy C.

    2007-06-01

    Analysis of a series of historical bathymetric surveys has revealed large changes in morphology and sedimentation from 1856 to 1983 in San Pablo Bay, California. In 1856, the morphology of the bay was complex, with a broad main channel, a major side channel connecting to the Petaluma River, and an ebb-tidal delta crossing shallow parts of the bay. In 1983, its morphology was simpler because all channels except the main channel had filled with sediment and erosion had planed the shallows creating a uniform gently sloping surface. The timing and patterns of geomorphic change and deposition and erosion of sediment were influenced by human activities that altered sediment delivery from rivers. From 1856 to 1887, high sediment delivery (14.1 × 10 6 m 3/yr) to San Francisco Bay during the hydraulic gold-mining period in the Sierra Nevada resulted in net deposition of 259 ± 14 × 10 6 m 3 in San Pablo Bay. This rapid deposition filled channels and increased intertidal mudflat area by 60% (37.4 ± 3.4 to 60.6 ± 6.2 km 2). From 1951 to 1983, 23 ± 3 × 10 6 m 3 of sediment was eroded from San Pablo Bay as sediment delivery from the Sacramento and San Joaquin Rivers decreased to 2.8 × 10 6 m 3/yr because of damming of rivers, riverbank protection, and altered land use. Intertidal mudflat area in 1983 was 31.8 ± 3.9 km 2, similar to that in 1856. Intertidal mudflat distribution in 1983, however, was fairly uniform whereas most of the intertidal mudflats were in the western part of San Pablo Bay in 1856. Sediment delivery, through its affect on shallow parts of the bay, was determined to be a primary control on intertidal mudflat area. San Pablo Bay has been greatly affected by human activities and will likely continue to erode in the near term in response to a diminished sediment delivery from rivers.

  3. Influence of Igneous Basement on Deep Sediment Microbial Diversity on the Eastern Juan de Fuca Ridge Flank.

    PubMed

    Labonté, Jessica M; Lever, Mark A; Edwards, Katrina J; Orcutt, Beth N

    2017-01-01

    Microbial communities living in deeply buried sediment may be adapted to long-term energy limitation as they are removed from new detrital energy inputs for thousands to millions of years. However, sediment layers near the underlying oceanic crust may receive inputs from below that influence microbial community structure and/or activity. As part of the Census of Deep Life, we used 16S rRNA gene tag pyrosequencing on DNA extracted from a spectrum of deep sediment-basement interface samples from the subsurface of the Juan de Fuca Ridge flank (collected on IODP Expedition 327) to examine this possible basement influence on deep sediment communities. This area experiences rapid sedimentation, with an underlying basaltic crust that hosts a dynamic flux of hydrothermal fluids that diffuse into the sediment. Chloroflexi sequences dominated tag libraries in all sediment samples, with variation in the abundance of other bacterial groups (e.g., Actinobacteria, Aerophobetes, Atribacteria, Planctomycetes, and Nitrospirae). These variations occur in relation to the type of sediment (clays versus carbonate-rich) and the depth of sample origin, and show no clear connection to the distance from the discharge outcrop or to basement fluid microbial communities. Actinobacteria-related sequences dominated the basalt libraries, but these should be viewed cautiously due to possibilities for imprinting from contamination. Our results indicate that proximity to basement or areas of seawater recharge is not a primary driver of microbial community composition in basal sediment, even though fluids diffusing from basement into sediment may stimulate microbial activity.

  4. [Vegetation influence on nutrients distribution in pore water of salt marsh sediment].

    PubMed

    Wang, Wei-Wei; Li, Dao-Ji; Gao, Lei

    2009-11-01

    The variations of nutrients in pore water of salt marsh sediment were surveyed in the middle intertidal zone of Chongming Dongtan during August 2007 to May 2008 to identify plant impact on nutrients distribution. The results show that NH4(+) -N and PO4(3-) -P concentrations are lower in pore water of Spartina alterniflora and Phragmites australis zones than in bare flat, and specially, NH4(+) -N concentrations in summer and autumn decrease by one more orders of magnitude. Compared to winter, nutrients concentrations are obviously higher during the period of plant growth, and plant biomass is clearly correlative to nitrogen and phosphorus. Vegetation growth influences nitrogen content intensively. NH4(-) -N concentrations in Spartina alterniflora and Phragmites australis zones are 44.21 and 74.38 micromol x L(-1) respectively, distinctly lower than that in bare flat and Scirpus mariquete zone (340.14 and 291.87 micromol x L(-1) respectively). Moreover, NO(x)(-) -N concentration is one to two order(s) of magnitude lower than NH4(+) -N, and its highest value exists in Phragmites australis zone (5.94 micromol x L(-1)). The results of molecule diffusive flux of nutrients in the surface sediment-overlying water interface indicate that marsh sediment is the source for SiO3(2-) -Si, NH4(+) -N and PO4(3-) -P, and the rank for NO(x)(-) -N (NO3(-) -N + NO2(-) -N), and NO(x)(-) -N flux from overlying water to sediment [16.23 micromol x (m2 x h)(-1)] is higher than NH4(+) -N flux from sediment to overlying water [15.53 micromol x (m2 x h)(-1)]. Vegetation growth accommodates nutrient structure of the estuarine ecosystem by affecting sediment-water interface mass flux and nutrient ratios in pore water and overlying water.

  5. CaCO 3 dissolution in California continental margin sediments: The influence of organic matter remineralization

    NASA Astrophysics Data System (ADS)

    Jahnke, Richard A.; Craven, Deborah B.; McCorkle, Daniel C.; Reimers, Clare E.

    1997-09-01

    In situ benthic flux chamber and oxygen microelectrode and shipboard porewater results have been used to quantify sea floor dissolution of CaCO 3 on the continental rise adjacent to central California, USA. The porewater distributions and benthic fluxes of O 2, NO 3-, TA, Ca 2+, δ 13C, and TIC are interpreted using a numerical simulation of organic matter remineralization and CaCO 3 dissolution in marine sediments. The processes considered in the simulation include: organic matter oxidation by O 2, NO 3, and SO 42-; CaCO 3 dissolution and precipitation; HS - and NH 4+ oxidation; and sediment mixing and sediment accumulation. Calculated benthic fluxes of O 2, NO 3-, TA, TIC, δ 13C, and Ca 2+; porewater concentrations of O 2, NO 3-, and NH 4+; and sediment distributions of organic carbon, CaCO 3, excess 210Pb, and 14C agree well with the measurements. Benthic fluxes of alkalinity and inferred CaCO 3 dissolution rates cannot be explained on the basis of dissolution driven solely by bottom water undersaturation. If the influence of metabolically-produced CO 2 is included, benthic fluxes are fully reconciled, however. This is in agreement with benthic chamber Ca 2+ and δ 13C results that independently imply substantial CaCO 3 dissolution in these sediments. The above observations are in contrast to those reported by Jahnke et al. (1994) for the west African continental rise and the western equatorial Pacific where 1-G diagenetic models predict dissolution fluxes larger than observed with benthic flux chambers. We conclude that the extent of metabolic CaCO 3 dissolution may vary regionally. Numerous factors, such as the depth of metabolic CO 2 production and CaCO 3 dissolution kinetics, are known or predicted to influence metabolic dissolution. Among the factors that should be considered in reconciling these observations are: (l) the extent to which sulfate reduction and reoxidation reactions may influence acid-base properties in surface sediments and (2) the total

  6. The impact of storms and stratification on sediment transport in the Rhine region of freshwater influence

    NASA Astrophysics Data System (ADS)

    Flores, Raúl P.; Rijnsburger, Sabine; Horner-Devine, Alexander R.; Souza, Alejandro J.; Pietrzak, Julie D.

    2017-05-01

    We present measurements of along and across-shore sediment transport in a region of the Dutch coast 10 km north of the Rhine River mouth. This section of the coast is characterized by strong vertical density stratification because it is within the midfield region of the Rhine region of freshwater influence, where processes typical of the far-field, such as tidal straining, are modified by the passage of distinct freshwater lenses at the surface. The experiment captured two storms, and a wide range of wind, wave, tidal and stratification conditions. We focus primarily on the mechanisms leading to cross-shore sediment flux at a mooring location in 12 m of water, which are responsible for the exchange of sediment between the nearshore and the inner shelf. Net transport during storms was directed offshore and influenced by cross-shelf winds, while net transport during spring tides was determined by the mean state of stratification. Tidal straining dominated during neap tides; however, cross-shore transport was negligible due to small sediment concentrations. The passage of freshwater lenses manifested as strong pulses of offshore transport primarily during spring tides. We observe that both barotropic and baroclinic processes are relevant for cross-shore transport at depth and, since transport rates due to these competing processes were similar, the net transport direction will be determined by the frequency and sequencing of these modes of transport. Based on our observations, we find that wind and wave-driven transport during storms tends move fine sediment offshore, while calmer, more stratified conditions move it back onshore.

  7. The influence of buried nodules on the mobility of metals in deep sea sediments

    NASA Astrophysics Data System (ADS)

    Heller, Christina; Kuhn, Thomas

    2017-04-01

    Hydrothermal fluids can extract significant amounts of heat from oceanic lithosphere by lateral fluid flow through permeable basaltic crust of an age of up to 65 Ma. Fluid recharge and discharge occur at basement outcrops in between impermeable pelagic deep sea sediments. Recharge of oxic seawater causes upward oxygen diffusion into sediments overlying the permeable basalt in areas proximal to recharge sites. It is suggested that this oxygen has a strong impact on sediments and Mn-nodules during fluid exposure time. The aim of this study is to investigate if/how fluid flow through oceanic crust influence the distribution and element budget of Mn-nodules. Nodules occur widespread at the seafloor of the Clarion-Clipperton Zone (CCZ) in the equatorial North Pacific and were analyzed in many studies worldwide. Nodules buried in the deep sea sediments could be found only rarely (von Stackelberg, 1997, Geol. Soc. Spec. Publ., 119: 153-176). High resolution side-scan sonar recordings (unpublished Data BGR Hannover) indicate that there exist a coherent layer of nodules buried in the sediments of the working area. During the expedition SO 240/FLUM nodules were found on the sediment surface in 4200 to 4300 m water depth as well as in the sediment down to 985 cm below seafloor. In general, nodules consist of different nm- to µm-thick, dense and porous layers. The geochemical composition of bulk nodules and single nodule layers were determined by XRF, ICP-MS/OES, XRD and by high resolution analyses with electron microprobe and LA-ICP-MS. Dense layers have low Mn/Fe ratios (<4) and high concentrations of Co, Zr and REY, while porous layers are characterized by high Mn/Fe ratios (> 10) and high Ni+Cu and Li concentrations. The different compositions depend on different formation processes of the layers. They were formed by metal precipitation from oxic (hydrogenetic) and suboxic (diagenetic) bottom-near seawater and/or pore water (Wegorzewski and Kuhn, 2014, Mar. Geol. 357, 123

  8. Influence of the sediment on lead speciation in the Tagus estuary.

    PubMed

    Mota, A M; Cruz, P; Vilhena, C; Gonçalves, M L S

    2005-04-01

    The aim of this work is to study the influence of the Tagus estuarine sediment on lead speciation in the overlying natural water. The water sample in the presence of the sediment was contaminated three times with Pb(II) in a laboratory experiment. In different periods of time, at 1-7 days after each contamination, small volumes of water were titrated with lead. The titration was followed by anodic stripping voltammetry in differential pulse mode. Before and after contamination systematic analysis of the voltammetric parameters (peak current, peak potential and peak width) were carried out to get a clear picture of Pb(II) complexation in the soluble fraction in contact with the sediment. Two main types of organic ligands, macromolecular ligands and small compounds, were detected before contamination. Both of them form labile complexes (degree of lability within the timescale of some milliseconds). The small compounds, with a diffusion coefficient similar to that of the free metal ion, present a homogeneous behaviour in terms of Pb complexation. On the other hand macromolecular ligands, with a diffusion coefficient of 1.2 x 10(-6) cm2s(-1), can be described by two different binding groups, which might be of phenolic and carboxylic type as presented by humic matter. The sediment eliminated lead contamination (10(-6) moldm(-3) was the maximum concentration added) from 12 dm3 of water (surface of 8 dm2) within 2 days. It was also found that the sediment released organic ligands responsible for both labile and inert Pb complexes "seen" by voltammetry. The release of organic ligands that decreases the bioavailability of Pb(II) was clearly detected 1 week after contamination. Therefore, the sediment acts as a buffer for lead through two mechanisms against lead contamination: removing lead ions from the solution and releasing organic ligands to the water column. In a short period of time the sediment responds as a self-cleaning system for Pb(II) contamination in the

  9. Influence of Cultivation and Cropping Systems on Production of Soil Sediment on Agricultural Land

    NASA Astrophysics Data System (ADS)

    Poposka, Hristina; Mukaetov, Dusko

    2017-04-01

    Soil conservation practices and in particular soil tillage and crop cultivation patterns are becoming an important issue in agricultural production. Combating soil erosion and diminishing its negative impact on agricultural soil imposes as a matter of vital interest which gained even greater significance, in a pronounced negative impact of climate change. Main objective of the three-year research and monitoring program was to evaluate the effects of the easy-to-use adaptive measures on intensity of soil erosion, and soil properties considering to be of crucial importance on run-off velocity and sediment loss, like: soil structure stability, soil infiltration rate, soil organic matter and soil moisture conservation. The influence of soil tillage practices and different cropping systems on soil intensity and sediment loss, has been monitored on specially designed soil erosion fields with standard dimensions (20m length x 4m. width), on a sloppy terrain (12% slope). The experimental field is located on heavily textured Chromic cambisol on saprolite. This is the predominant soil type on the sloppy terrains in the country, usually under intensive agricultural activities Soil texture and physical characteristics were thoroughly investigated in order to determine the base soil conditions. The influence of downslope and contour ploughing on quantity of eroded sediment has been monitored in three consecutive years. The eroded sediment has been collected periodically on a weekly base and after intensive rainfalls. The intensity of soil erosion under most widespread cropping systems in the country, like: a) cereals as a monoculture, b) crop rotation, and c) perennial grass, was monitored as well. The collected sediment was examined in order to determine the quantity of soil organic matter and nutrient loss (nitrogen, phosphorus and potassium). Soil chemical properties are examined after each vegetative season in order to quantify the effect of tillage and cropping systems on

  10. Rare earth elements in intertidal sediments of Bohai Bay, China: concentration, fractionation and the influence of sediment texture.

    PubMed

    Zhang, Yong; Gao, Xuelu; Arthur Chen, Chen-Tung

    2014-07-01

    Surface sediments from intertidal Bohai Bay were assessed using a four-step sequential extraction procedure to determine their concentrations of rare earth elements (REEs) and the chemical forms in which those elements were present. The normalized ratios La/Gd and La/Yb showed that LREE contents were not significantly higher than the middle REEs or HREE contents. A negative Ce anomaly and positive Eu were observed in sand and silty sand sediments, whereas no significant Ce or Eu anomaly was found in clayey silt sediments. Residual fraction of REEs accounted for the majority of their total concentrations. Middle REEs were more easily leached than other REEs, especially in clayey silt sediment. REEs contents in the surface sediment from the intertidal Bohai Sea were consistent with data from the upper continental crust and China shallow sea sediments, indicating that they were generally unaffected by heavily anthropogenic effects from adjacent areas.

  11. Influence of pH on plutonium desorption/solubilization from sediment.

    PubMed

    Kaplan, Daniel I; Powell, Brian A; Gumapas, Leo; Coates, John T; Fjeld, Robert A; Diprete, David P

    2006-10-01

    ). Slight changes in system pH can have a large impact on Pu solubility and the tendency of Pu to sorb to sediment, thereby influencing Pu subsurface mobility.

  12. Experimental investigation of the influence of the sediment size distribution on bedload transport

    NASA Astrophysics Data System (ADS)

    Houssais, M.; Lajeunesse, E.

    2012-04-01

    We report the results of an experimental investigation of bedload transport of a bimodal sediment bed. The experiments are carried out in a tilted rectangular flume, partially filled with an erodible bed composed of a mixture of 2 populations of quartz grains of sizes D1 = 0.7mm and D2 = 2.2mm, respectively. The sediment bed is sheared by a steady and spatially uniform turbulent flow. Using a high-speed video imaging system, we measure the average velocity and the surface density of the moving particles of each size fraction. We show that they follow laws similar to those reported by Lajeunesse et al. [2010a] for an homogenous sediment bed. Indeed, noting τi* and τc,i*, the Shields and threshold Shields number calculated for the grain size Di, we find that (1) the surface density of moving particles increases linearly with τi*- τc,i*; (2) the average particle velocity increases linearly with τi*1/2 - τc,i*1/2, with a finite nonzero value at threshold. The influence of the sediment bed size distribution appears to be encoded in the value of the threshold Shields number which is found to vary with the proportion of small grains.

  13. Influence of introduced Sonneratia apetala on nutrients and heavy metals in intertidal sediments, South China.

    PubMed

    Li, Ruili; Chai, Minwei; Li, Rongyu; Xu, Hualin; He, Bei; Qiu, Guo Yu

    2017-01-01

    To investigate the influence of Sonneratia apetala on nutrients and heavy metals in intertidal sediments, sediment cores of S. apetala marsh and mudflat in Shenzhen Bay, China were analyzed. The results showed that S. apetala improved sediment nutrient properties due to increased total carbon (TC), total nitrogen (TN), and total sulfur (TS). The levels of heavy metals were higher in S. apetala site than in mudflat, including chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). In S. apetala site, TC, TN, and TS were not positively correlated with Cr, Ni, As, Cd, and Pb, indicating their less important roles in trapping heavy metals. There were positive correlations among Ni, Cu, Zn, and Cd in both sites, suggesting similar anthropogenic source. Levels of As were higher than the probable effect level at both sites, indicating their toxicological importance. The geo-accumulation index and potential ecological risk index revealed higher metal contaminations in S. apetala site, especially for Cd, Hg, and As. Multivariate analysis implied that S. apetala alter the biogeochemical cycle of Cd and Cr to a certain extent. These findings indicate that S. apetala may improve soil nutrient properties and facilitate heavy metal accumulation in intertidal sediments.

  14. [Influence of Submerged Plants on Microbial Community Structure in Sediment of Hongze Lake].

    PubMed

    Zhang, Ding-yu; Zhang, Ting-xi; Dong, Dan-ping; Li, De-fang; Wang, Guo-xiang

    2016-05-15

    Phospholipid fatty acids (PLFAs) method was applied to analyze the influence of submerged plants on sediment microbial community structure, in order to investigate the changes of sediment microbial community structure for different kinds of the submerged plants in different growth periods. Particularly, Potamogeton crispus L., Potamogeton pectinatus L and the mixed group were chosen as the typical submerged plants in Hongze Lake for investigation in this paper. The results indicated that the change of total PLFAs in different periods was significant, on the contrary, the PLFA change for different groups in the same period was insignificant. The values of G⁺ PLFA/G⁻ PLFA in the submerged plant group were also highly related to the different growth periods, which demonstrated that the root function of the submerged plant had a severe impact on the microbial community in sediment. Furthermore, some environmental factors, such as Temperature, pH, TOC and DO, were correlated to characteristic phospholipid of PLFAs in sediment, which means the environmental factors could also affect the microbial community structure.

  15. The influence of bottom boundary layer hydrodynamics on sediment focusing in a contaminated bay.

    PubMed

    Graham, Neil D; Bouffard, Damien; Loizeau, Jean-Luc

    2016-12-01

    Understanding the dynamics and fate of particle bound contaminants is important for mitigating potential environmental, economic and health impacts linked to their presence. Vidy Bay, Lake Geneva (Switzerland), is contaminated due to the outfall and overflow from the wastewater treatment plant of the City of Lausanne. This study was designed to investigate the fate of particle-bound contaminants with the goal of providing a more complete picture of contaminant pathways within the bay and their potential spread to the main basin. This goal was achieved by investigating the sediment transport dynamics, using sediment traps and radionuclide tracers, and ascertaining how local bottom-boundary hydrodynamic conditions (temperature, turbidity, current velocity and direction) influence these dynamics. Results of the study indicated that sedimentation rates and lateral advections increased vertically with proximity to the lakebed and laterally with proximity to shore, indicating the presence of sediment focusing in the bay. Hydrodynamic measurements showed the persistent influence of a gyre within the bay, extending down to the lake bed, while just outside of the bay circulation was influenced by the seasonal patterns of the main basin. Calculated mean displacement distances in the bay indicated that suspended particles can travel ∼3 km per month, which is 1.7 times the width of the Vidy Bay gyre. This results in a residence time of approximately 21 days for suspended particles, which is much greater than previously modelled results. The calculated mobility Shield parameter never exceeded the threshold shear stress needed for resuspension in deeper parts of the bay. In such, increased lateral advections to the bay are not likely due to local resuspension but rather external particle sources, such as main basin or shallow, littoral resuspensions. These external sources coupled with an increased residence time and decreased current velocity within the bay are the

  16. 76 FR 33721 - Takes of Marine Mammals Incidental to Specified Activities; Harbor Activities Related to the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-09

    ... sediment per dredging cycle. Dredging would involve the use of heavy equipment, including a clamshell... on the beach adjacent to the harbor and on rocks for any flushing or other behaviors as a result of... harbor only when the tide is too high for harbor seals to haul-out on the rocks; reducing speed to 1.5 to...

  17. Influence of sediment characteristics on the composition of soft-sediment intertidal communities in the northern Gulf of Mexico

    PubMed Central

    Henkel, Jessica R.; Sigel, Bryan J.; Taylor, Caz M.

    2015-01-01

    Benthic infaunal communities are important components of coastal ecosystems. Understanding the relationships between the structure of these communities and characteristics of the habitat in which they live is becoming progressively more important as coastal systems face increasing stress from anthropogenic impacts and changes in climate. To examine how sediment characteristics and infaunal community composition were related along the northern Gulf of Mexico coast, we sampled intertidal infaunal communities at seven sites covering common habitat types at a regional scale. Across 69 samples, the communities clustered into four distinct groups on the basis of faunal composition. Nearly 70% of the variation in the composition of the communities was explained by salinity, median grain size, and total organic content. Our results suggest that at a regional level coarse habitat characteristics are able to explain a large amount of the variation among sites in infaunal community structure. By examining the relationships between infaunal communities and their sedimentary habitats, we take a necessary first step that will allow the exploration of how changes in habitat and community composition influence higher trophic levels and ecosystem scale processes. PMID:26157603

  18. Bacterial biogeography influenced by shelf-basin exchange in the Arctic surface sediment at the Chukchi Borderland.

    PubMed

    Han, Dukki; Nam, Seung-Il; Ha, Ho Kyung; Kim, Hyoungjun; Sadowsky, Michael J; Lee, Yoo Kyung; Hur, Hor-Gil

    2016-02-01

    It has been known that continental shelves around the Arctic Ocean play a major role in the ventilation of the deep basins as a consequence of shelf-basin exchange. In the present study, we found that bacterial assemblage of the surface sediment was different from that of seawater while seawater harboured local bacterial assemblages in response to the Arctic hydrography. This finding suggests that the Arctic seafloor sediments may have distinctive bacterial biogeography. Moreover, the distribution of bacterial assemblages and physicochemical properties in surface sediments changed gradually from the Arctic continental shelf to deep-sea basin. Based on the results, bacterial biogeography in the Arctic seafloor sediments may be influenced by winnowing and re-deposition of surface sediments through the sediment gravity flow. The present study offers a deeper understanding of shelf convection and its role for the construction of bacterial assemblages in the Arctic Ocean. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. The influence of grain size ratio upon the relative mobility in bimodal sediment mixtures

    NASA Astrophysics Data System (ADS)

    Dudill, Ashley; Frey, Philippe

    2014-05-01

    The behaviour of grain mixtures varies from that of uniform grain, which has implications for bedload sediment transport in gravel-bed rivers. In particular, sediment mixtures act to modify the level of mobility within the bed, leading to aggradation or degradation, which has significant implications for river stability. Previous work has reported upon this change in mobility within bimodal mixtures; however we do not know how far grain size ratio influences these results. We hypothesise that there is a link between the change in levels of mobility and the grain size ratio due to varying amounts of infiltration, which controls the hiding/exposure function. This poster will present experimental results from an investigation designed to isolate the influence of grain size ratio upon the change in levels of mobility in bimodal sediment mixtures. This experimental investigation was undertaken using various sizes of spherical particles in a relatively narrow flume. Using this arrangement, we are able to observe effects at the particle scale in order to understand the individual and bulk grain behaviour.

  20. Degradation of Herbicides in the Tropical Marine Environment: Influence of Light and Sediment

    PubMed Central

    Mercurio, Philip; Mueller, Jochen F.; Eaglesham, Geoff; O'Brien, Jake; Flores, Florita; Negri, Andrew P.

    2016-01-01

    Widespread contamination of nearshore marine systems, including the Great Barrier Reef (GBR) lagoon, with agricultural herbicides has long been recognised. The fate of these contaminants in the marine environment is poorly understood but the detection of photosystem II (PSII) herbicides in the GBR year-round suggests very slow degradation rates. Here, we evaluated the persistence of a range of commonly detected herbicides in marine water under field-relevant concentrations and conditions. Twelve-month degradation experiments were conducted in large open tanks, under different light scenarios and in the presence and absence of natural sediments. All PSII herbicides were persistent under control conditions (dark, no sediments) with half-lives of 300 d for atrazine, 499 d diuron, 1994 d hexazinone, 1766 d tebuthiuron, while the non-PSII herbicides were less persistent at 147 d for metolachlor and 59 d for 2,4-D. The degradation of herbicides was 2–10 fold more rapid in the presence of a diurnal light cycle and coastal sediments; apart from 2,4-D which degraded more slowly in the presence of light. Despite the more rapid degradation observed for most herbicides in the presence of light and sediments, the half-lives remained > 100 d for the PS II herbicides. The effects of light and sediments on herbicide persistence were likely due to their influence on microbial community composition and its ability to utilise the herbicides as a carbon source. These results help explain the year-round presence of PSII herbicides in marine systems, including the GBR, but more research on the transport, degradation and toxicity on a wider range of pesticides and their transformation products is needed to improve their regulation in sensitive environments. PMID:27806103

  1. Degradation of Herbicides in the Tropical Marine Environment: Influence of Light and Sediment.

    PubMed

    Mercurio, Philip; Mueller, Jochen F; Eaglesham, Geoff; O'Brien, Jake; Flores, Florita; Negri, Andrew P

    2016-01-01

    Widespread contamination of nearshore marine systems, including the Great Barrier Reef (GBR) lagoon, with agricultural herbicides has long been recognised. The fate of these contaminants in the marine environment is poorly understood but the detection of photosystem II (PSII) herbicides in the GBR year-round suggests very slow degradation rates. Here, we evaluated the persistence of a range of commonly detected herbicides in marine water under field-relevant concentrations and conditions. Twelve-month degradation experiments were conducted in large open tanks, under different light scenarios and in the presence and absence of natural sediments. All PSII herbicides were persistent under control conditions (dark, no sediments) with half-lives of 300 d for atrazine, 499 d diuron, 1994 d hexazinone, 1766 d tebuthiuron, while the non-PSII herbicides were less persistent at 147 d for metolachlor and 59 d for 2,4-D. The degradation of herbicides was 2-10 fold more rapid in the presence of a diurnal light cycle and coastal sediments; apart from 2,4-D which degraded more slowly in the presence of light. Despite the more rapid degradation observed for most herbicides in the presence of light and sediments, the half-lives remained > 100 d for the PS II herbicides. The effects of light and sediments on herbicide persistence were likely due to their influence on microbial community composition and its ability to utilise the herbicides as a carbon source. These results help explain the year-round presence of PSII herbicides in marine systems, including the GBR, but more research on the transport, degradation and toxicity on a wider range of pesticides and their transformation products is needed to improve their regulation in sensitive environments.

  2. High Levels of Sediment Contamination Have Little Influence on Estuarine Beach Fish Communities

    PubMed Central

    McKinley, Andrew C.; Dafforn, Katherine A.; Taylor, Matthew D.; Johnston, Emma L.

    2011-01-01

    While contaminants are predicted to have measurable impacts on fish assemblages, studies have rarely assessed this potential in the context of natural variability in physico-chemical conditions within and between estuaries. We investigated links between the distribution of sediment contamination (metals and PAHs), physico-chemical variables (pH, salinity, temperature, turbidity) and beach fish assemblages in estuarine environments. Fish communities were sampled using a beach seine within the inner and outer zones of six estuaries that were either heavily modified or relatively unmodified by urbanization and industrial activity. All sampling was replicated over two years with two periods sampled each year. Shannon diversity, biomass and abundance were all significantly higher in the inner zone of estuaries while fish were larger on average in the outer zone. Strong differences in community composition were also detected between the inner and outer zones. Few differences were detected between fish assemblages in heavily modified versus relatively unmodified estuaries despite high concentrations of sediment contaminants in the inner zones of modified estuaries that exceeded recognized sediment quality guidelines. Trends in species distributions, community composition, abundance, Shannon diversity, and average fish weight were strongly correlated to physico-chemical variables and showed a weaker relationship to sediment metal contamination. Sediment PAH concentrations were not significantly related to the fish assemblage. These findings suggest that variation in some physico-chemical factors (salinity, temperature, pH) or variables that co-vary with these factors (e.g., wave activity or grain size) have a much greater influence on this fish assemblage than anthropogenic stressors such as contamination. PMID:22039470

  3. Influence of acid volatile sulfides and metal concentrations on metal partitioning in contaminated sediments

    USGS Publications Warehouse

    Lee, J.-S.; Lee, B.-G.; Luoma, S.N.; Choi, H.J.; Koh, C.-H.; Brown, C.L.

    2000-01-01

    The influence of acid volatile sulfide (AVS) on the partitioning of Cd, Ni, and Zn in porewater (PW) and sediment as reactive metals (SEM, simultaneously extracted metals) was investigated in laboratory microcosms. Two spiking procedures were compared, and the effects of vertical geochemical gradients and infaunal activity were evaluated. Sediments were spiked with a Cd-Ni-Zn mixture (0.06, 3, 7.5 ??mol/g, respectively) containing four levels of AVS (0.5, 7.5, 15, 35 ??mol/g). The results were compared to sediments spiked with four levels of Cd-Ni-Zn mixtures at one AVS concentration (7.5 ??mol/g). A vertical redox gradient was generated in each treatment by an 18-d incubation with an oxidized water column. [AVS] in the surface sediments decreased by 65-95% due to oxidation during incubation; initial [AVS] was maintained at 0.5-7.5 cm depth. PW metal concentrations were correlated with [SEM - AVS] among all data. But PW metal concentrations were variable, causing the distribution coefficient, Kd(pw) (the ratio of [SEM] to PW metal concentrations) to vary by 2-3 orders of magnitude at a given [SEM - AVS]. One reason for the variability was that vertical profiles in PW metal concentrations appeared to be influenced by diffusion as well as [SEM - AVS]. The presence of animals appeared to enhance the diffusion of at least Zn. The generalization that PW metal concentrations are controlled by [SEM - AVS] is subject to some important qualifications if vertical gradients are complicated, metal concentrations vary, or equilibration times differ.The influence of acid volatile sulfide (AVS) on the partitioning of Cd, Ni, and Zn in porewater (PW) and sediment as reactive metals (SEM, simultaneously extracted metals) was investigated in laboratory microcosms. Two spiking procedures were compared, and the effects of vertical geochemical gradients and infaunal activity were evaluated. Sediments were spiked with a Cd-Ni-Zn mixture (0.06, 3, 7.5 ??mol/g, respectively) containing

  4. Organic content influences sediment microbial fuel cell performance and community structure.

    PubMed

    Zhao, Qing; Li, Ruying; Ji, Min; Ren, Zhiyong Jason

    2016-11-01

    This study constructed sediment microbial fuel cells (SMFCs) with different organic loadings without the amendment of external substrates, and it investigated how such variation affects electricity generation and microbial community structure. Results found sediment characteristics significantly influenced SMFC performance and appropriate organic content is important to maintain stable power outputs. SMFCs with loss of ignition (LOI) of 5% showed the most reliable performance in this study, while high organic content (LOI 10-16%) led to higher but very unstable voltage output because of biogas accumulation and worm activities. SMFCs with low organic content (1-3%) showed low power output. Different bacterial communities were found in SMFCs shown various power generation performance even those with similar organic contents. Thermodesulfovibrionaceae was found closely related to the system startup and Desulfobulbaceae showed great abundance in SMFCs with high power production.

  5. Arsenic fractionation in estuarine sediments: Does coastal eutrophication influence As behavior?

    PubMed

    Sá, Fabian; Sanders, Christian J; Patchineelam, Sambasiva Rao; Machado, Eunice da Costa; Lombardi, Ana Teresa

    2015-07-15

    The Paranaguá Estuarine Complex (PEC) includes the naturally oligotrophic (NO) Mel Island which is surrounded by sea grasses, a naturally eutrophic (NE) Benito Inlet adjacent to mangrove wetlands and the highly impacted eutrophic (IE) Paranaguá Bay, home of one of Brazil's largest ports. The results from this study indicate that reactive As and pyrite increase with sediment depth near Paranaguá port in the IE region. At the NE region, near a mangrove fringe, the reactive As, Fe, Mn and pyrite remained relatively high along the sediment column while near the sea grasses at NO the As contents were low. The degree of trace metal pyritization (DTMP) and the degree of pyritization (DOP) was highest at the IE site, slightly increasing with depth. These baseline results indicate that influence of trophic conditions and presence of marine vegetation may be directly related to As behavior in coastal systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Artificial water sediment regulation scheme influences morphology, hydrodynamics and nutrient behavior in the Yellow River estuary

    NASA Astrophysics Data System (ADS)

    Xu, Bochao; Yang, Disong; Burnett, William C.; Ran, Xiangbin; Yu, Zhigang; Gao, Maosheng; Diao, Shaobo; Jiang, Xueyan

    2016-08-01

    Anthropogenic controls on water and sediment may play important roles in river system transformations and morphological evolution, which could further affect coastal hydrodynamics and nutrient behavior. We used geochemical tracers to evaluate the influence of an intentional large release of water and sediment during the so-called "Water Sediment Regulation Scheme" (WSRS) on estuarine morphology, hydrodynamics and nutrients in the Yellow River estuary, China. We discovered that there was a newly formed small delta in the river mouth after the 2013 WSRS. This new morphologic feature altered terrestrial material distribution patterns from a single plume to a two-plume pattern within the estuary. Our results show that the WSRS significantly influenced the study area in the following ways: (1) Radium and nutrient concentrations were significantly elevated (two to four times), especially along the two river outlets. (2) Estuarine mixing was about two times stronger during WSRS than before. Average aerial mixing rates before and during WSRS were 50 ± 26 km2 d-1 and 89 ± 51 km2 d-1, respectively. (3) Our data is consistent with P limitation and suggest that stoichiometrically based P limitation was even more severe during WSRS. (4) All river-derived nutrients were thoroughly consumed within one to two weeks after entry to near-shore waters. (5) The extent of the area influenced by terrestrial nutrients was two to three times greater during WSRS. Human influence, such as triggered by WSRS regulations, should thus be considered when studying biogeochemical processes and nutrient budgets in situations like the Yellow River estuary.

  7. River longitudinal profiles and bedrock incision models: Stream power and the influence of sediment supply

    NASA Astrophysics Data System (ADS)

    Sklar, Leonard; Dietrich, William E.

    The simplicity and apparent mechanistic basis of the stream power river incision law have led to its wide use in empirical and theoretical studies. Here we identify constraints on its calibration and application, and present a mechanistic theory for the effects of sediment supply on incision rates which spotlights additional limitations on the applicability of the stream power law. On channels steeper than about 20%, incision is probably dominated by episodic debris flows, and on sufficiently gentle slopes, sediment may bury the bedrock and prevent erosion. These two limits bound the application of the stream power law and strongly constrain the possible combination of parameters in the law. In order to avoid infinite slopes at the drainage divide in numerical models of river profiles using the stream power law it is commonly assumed that the first grid cell is unchanneled. We show, however, that the size of the grid may strongly influence the calculated equilibrium relief. Analysis of slope-drainage area relationships for a river network in a Northern California watershed using digital elevation data and review of data previously reported by Hack reveal that non-equilibrium profiles may produce well defined slope-area relationships (as expected in equilibrium channels), but large differences between tributaries may point to disequilibrium conditions. To explore the role of variations in sediment supply and transport capacity in bedrock incision we introduce a mechanistic model for abrasion of bedrock by saltating bedload. The model predicts that incision rates reach a maximum at intermediate levels of sediment supply and transport capacity. Incision rates decline away from the maximum with either decreasing supply (due to a shortage of tools) or increasing supply (due to gradual bed alluviation), and with either decreasing transport capacity (due to less energetic particle movement) or increasing transport capacity (due less frequent particle impacts per unit bed

  8. Influence of sediment-organic matter quality on growth and polychlorobiphenyl bioavailability in Echinodermata (Amphiura filiformis)

    SciTech Connect

    Gunnarsson, J.S.; Granberg, M.E.; Nilsson, H.C.; Rosenberg, R.; Hellman, B.

    1999-07-01

    Sediment total organic carbon (TOC) content is considered to be a primary food source for benthic invertebrates and a major factor influencing the partitioning and bioavailability of sediment-associated organic contaminants. Most studies report that both toxicity and uptake of sediment-associated contaminants by benthic organisms are inversely proportional to sediment TOC content. The aim of this study was to determine the importance of the TOC quality for the bioavailability of sediment-associated organic contaminants and the growth of benthic macrofauna. The common infaunal brittle star Amphiura filiformis was exposed to a base sediment covered by a {sup 14}C-polychlorobipenyl (3,3{prime}4,4{prime}-{sup 14}C-tetrachlorobiphenyl (TCB)) contaminated top layer (0--2 cm), enriched to the same TOC content with 31 g TOC/m{sup 2} of different quality and origin. The following carbon sources, ranging from labile to refractory, were used: (1) green macroalga (Ulva lactuca), (2) brown macroalga (Ascophyllum nodosum), (3) eelgrass (Zostera Marina), (4) phytoplankton (Ceratium spp.), and (5) lignins of terrestrial origin. Characterization of the organic matter quality was accomplished by measuring the content of amino acids, lipids, C, N, and polyphenolic compounds. The reactivity of the sedimentary organic matter was assessed by means of respiration and dissolved inorganic nitrogen flux measurements. The experiment was carried out in 1-L glass jars, each containing four brittle stars and the contaminated and enriched sediment. The jars were circulated in a flow-through mode with filtered seawater. Somatic growth (regeneration of a precut arm) and bioaccumulation of {sup 14}C-TCB were measured at 10 sampling occasions during 48 d of exposure. Growth rates, TCB uptake rates, and steady-state concentrations differed significantly between treatments and were correlated to the qualities of the organic substrates. The greatest TCB accumulation and growth were observed in

  9. Sediment composition influences spatial variation in the abundance of human pathogen indicator bacteria within an estuarine environment.

    PubMed

    Perkins, Tracy L; Clements, Katie; Baas, Jaco H; Jago, Colin F; Jones, Davey L; Malham, Shelagh K; McDonald, James E

    2014-01-01

    Faecal contamination of estuarine and coastal waters can pose a risk to human health, particularly in areas used for shellfish production or recreation. Routine microbiological water quality testing highlights areas of faecal indicator bacteria (FIB) contamination within the water column, but fails to consider the abundance of FIB in sediments, which under certain hydrodynamic conditions can become resuspended. Sediments can enhance the survival of FIB in estuarine environments, but the influence of sediment composition on the ecology and abundance of FIB is poorly understood. To determine the relationship between sediment composition (grain size and organic matter) and the abundance of pathogen indicator bacteria (PIB), sediments were collected from four transverse transects of the Conwy estuary, UK. The abundance of culturable Escherichia coli, total coliforms, enterococci, Campylobacter, Salmonella and Vibrio spp. in sediments was determined in relation to sediment grain size, organic matter content, salinity, depth and temperature. Sediments that contained higher proportions of silt and/or clay and associated organic matter content showed significant positive correlations with the abundance of PIB. Furthermore, the abundance of each bacterial group was positively correlated with the presence of all other groups enumerated. Campylobacter spp. were not isolated from estuarine sediments. Comparisons of the number of culturable E. coli, total coliforms and Vibrio spp. in sediments and the water column revealed that their abundance was 281, 433 and 58-fold greater in sediments (colony forming units (CFU)/100g) when compared with the water column (CFU/100ml), respectively. These data provide important insights into sediment compositions that promote the abundance of PIB in estuarine environments, with important implications for the modelling and prediction of public health risk based on sediment resuspension and transport.

  10. Evaluation of Sediment Contamination in Pearl Harbor

    DTIC Science & Technology

    1992-06-01

    migration pathway. The burrowing activities (bioturbation) by bottom-dwelling organisms such as snapping shrimp , mantis shrimp , worms, and certain...activities of organisms modifies many pollutant substances. The bioaccumulation of contaminants by marine organisms such as oysters, clams, crabs, shrimp ...Mercenaria mercenaria) and adult shrimp (Penaeus vannamet) in a flow-through seawater system. Adult brine shrimp (Artemia salina) and postlarval

  11. Influence of Sea Level Rise on Tidal Wetland Sediment and Carbon Accumulation Under Differing Fluvial Sediment Supply in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Peck, E. K.; Wheatcroft, R. A.; Brophy, L.

    2016-12-01

    Despite their provision of numerous ecosystem services including blue carbon burial, the dominant factor - relative sea level rise (RSLR) or fluvial sediment supply - controlling the formation and growth of tidal wetlands remains debated. This uncertainty is due mainly to confounding variables, including tidal range, water temperature, and wetland plant assemblages; thus, comparisons within and amongst tidal wetlands are often equivocal. Estuaries in the Pacific Northwest, despite remaining understudied relative to US East and Gulf Coast and European estuaries, provide unique opportunities as natural laboratories because they exhibit enough commonalities for comparison yet maintain diversity in characteristics such as size, RSLR, and river discharge. To better understand the relative influences of RSLR and sediment supply on tidal wetland accretion, three estuaries in Oregon (Youngs Bay, Tillamook Bay, and Salmon River Estuary) of differing sediment supply but similar RSLR were chosen for analysis of sediment and carbon accumulation rates. Sediment cores were collected from the intertidal zone of each estuary and analyzed for sediment, mass, and carbon accumulation rates using 210Pb and 137Cs; CT-image-derived bulk density; and organic carbon analysis by loss on ignition and elemental analysis. Preliminary results indicate that though the three estuaries vary in mean annual discharge from 15 to 130 m3 s-1 and thus experience vastly different sediment loads, average sediment accumulation rates were 2.6 ± 0.6 (n = 5), 2.5 ± 0.3 (n = 4), and 2.9 ± 0.6 (n = 2) mm yr-1 for Youngs Bay, Tillamook Bay, and Salmon River Estuary respectively. Modern RSLR, which ranges from 0.7 ± 0.2 to 1.1 ± 0.2 mm yr-1 in these estuaries, appears to control marsh accretion rates.

  12. Influence of algal bloom degradation on nutrient release at the sediment-water interface in Lake Taihu, China.

    PubMed

    Zhu, Mengyuan; Zhu, Guangwei; Zhao, Linlin; Yao, Xin; Zhang, Yunlin; Gao, Guang; Qin, Boqiang

    2013-03-01

    Algal bloom could drastically influence the nutrient cycling in lakes. To understand how the internal nutrient release responds to algal bloom decay, water and sediment columns were sampled at 22 sites from four distinct regions of China's eutrophic Lake Taihu and incubated in the laboratory to examine the influence of massive algal bloom decay on nutrient release from sediment. The column experiment involved three treatments: (1) water and sediment (WS); (2) water and algal bloom (WA); and (3) water, sediment, and algal bloom (WSA). Concentrations of dissolved oxygen (DO), total nitrogen (TN), total phosphorus (TP), ammonium (NH (4) (+) -N), and orthophosphate (PO (4) (3-) -P) were recorded during incubation. The decay of algal material caused a more rapid decrease in DO than in the algae-free controls and led to significant increases in NH (4) (+) -N and PO (4) (3-) -P in the water. The presence of algae during the incubation had a regionally variable effect on sediment nutrient profiles. In the absence of decaying algae (treatment WS), sediment nutrient concentrations decreased during the incubation. In the presence of blooms (WSA), sediments from the river mouth released P to the overlying water, while sediments from other regions absorbed surplus P from the water. This experiment showed that large-scale algal decay will dramatically affect nutrient cycling at the sediment-water interface and would potentially transfer the function of sediment as "container" or "supplier" in Taihu, although oxygen exchange with atmosphere in lake water was stronger than in columns. The magnitude of the effect depends on the physical-chemical character of the sediments.

  13. Petroleum-influenced beach sediments of the Campeche Bank, Mexico: diversity and bacterial community structure assessment.

    PubMed

    Rosano-Hernández, María C; Ramírez-Saad, Hugo; Fernández-Linares, Luis

    2012-03-01

    The bacterial diversity and community structure were surveyed in intertidal petroleum-influenced sediments of ≈ 100 km of a beach, in the southern Gulf of Mexico. The beach was divided in twenty sampling sites according to high, moderate and low petroleum influence. Densities of cultured heterotrophic (HAB) and hydrocarbon degrading bacteria (HDB) were highly variable in sediments, with little morphological assortment in colonies. PCR-RISA banding patterns differentiated distinct communities along the beach, and the bacterial diversity changed inversely to the degree of petroleum hydrocarbon influence: the higher TPH concentration, the lower genotype diversity. Seven DNA sequences (Genbank EF191394 -EF191396 and EF191398 -EF191401) were affiliated to uncultured members of Gemmatimonas, Acidobacterium, Desulfobacteraceae, Rubrobacterales, Actinobacterium and the Fibrobacteres/Acidobacteria group; all the above taxa are known for having members with active roles in biogeochemical transformations. The remaining sequences (EF191388 - EF191393 and EF191397) affiliated to Pseudoalteromonas, and to oil-degrading genera such as Pseudomonas, Vibrio and Marinobacter, being the last one an obligate oil-degrading bacterium. An exchange of bacteria between the beach and the oil seep environment, and the potential cleaning-up role of bacteria at the southern Gulf of Mexico are discussed.

  14. Stormwater sediment and bioturbation influences on hydraulic functioning, biogeochemical processes, and pollutant dynamics in laboratory infiltration systems.

    PubMed

    Nogaro, Geraldine; Mermillod-Blondin, Florian

    2009-05-15

    Stormwater sediments that accumulate at the surface of infiltration basins reduce infiltration efficiencies by physical clogging and produce anoxification in the subsurface. The present study aimed to quantify the influence of stormwater sediment origin (urban vs industrial catchments) and the occurrence of bioturbators (tubificid worms) on the hydraulic functioning, aerobic/anaerobic processes, and pollutant dynamics in stormwater infiltration systems. In laboratory sediment columns, effects of stormwater sediments and tubificids were examined on hydraulic conductivity, microbial processes, and pollutant releases. Significant differences in physical (particle size distribution) and chemical characteristics betoveen the two stormwater sediments led to distinct effects of these sediments on hydraulic and biogeochemical processes. Bioturbation by tubificid worms could increase the hydraulic conductivity in stormwater infiltration columns, but this effect depended on the characteristics of the stormwater sediments. Bioturbation-driven increases in hydraulic conductivity stimulated aerobic microbial processes and enhanced vertical fluxes of pollutants in the sediment layer. Our results showed that control of hydraulic functioning by stormwater sediment characteristics and/ or biological activities (such as bioturbation) determined the dynamics of organic matter and pollutants in stormwater infiltration devices.

  15. Influence of long-term sediment transport on contaminant dispersal in a turbid estuary

    NASA Astrophysics Data System (ADS)

    Uncles, R. J.; Woodrow, T. Y.; Stephens, J. A.

    1987-11-01

    Theoretical calculations are made of the long-term transport of fine sediment in a turbid estuary, and its possible consequences for the tidally averaged distribution of a contaminant whose partitioning between dissolved and particulate phases is dependent on salinity. It is found that the partitioning has a crucial effect on the levels of dissolved contaminant, in agreement with the observations of MORRIS (1986, The Science of the Total Environment, 49, 297-304). Calculations also imply that the vertical fluxes of particulate contaminant between water column and bed have a profound influence on these levels.

  16. Pearl Harbor Biological Survey

    DTIC Science & Technology

    1974-08-30

    snail-like hermit crab isopod crustacean mantis shrimp peanut worm sea anemone sea cucumber sedentary polychaete worm snapping shrimp tanaid...vegetation..." and typified In Pearl Harbor by organisms such as bryozoans, shrimp , tunlcates, anemones, etc.; 2) the infauna (Figure 2.2-2) "comprising...Harbor by organisms such as alpheld shrimp , bivalve mollusca, vv certain errant and sedentary polychaetes, slpunculld worms, etc.; and 3) "bottom

  17. Sediment delivery ratio of single flood events and the influencing factors in a headwater basin of the Chinese Loess Plateau.

    PubMed

    Zheng, Mingguo; Liao, Yishan; He, Jijun

    2014-01-01

    Little is known about the sediment delivery of single flood events although it has been well known that the sediment delivery ratio at the inter-annual time scale is close to 1 in the Chinese Loess Plateau. This study examined the sediment delivery of single flood events and the influencing factors in a headwater basin of the Loess Plateau, where hyperconcentrated flows are dominant. Data observed from plot to subwatershed over the period from 1959 to 1969 were presented. Sediment delivery ratio of a single event (SDRe) was calculated as the ratio of sediment output from the subwatershed to sediment input into the channel. It was found that SDRe varies greatly for small events (runoff depth <5 mm or rainfall depth <30 mm) and remains fairly constant (approximately between 1.1 and 1.3) for large events (runoff depth >5 mm or rainfall depth >30 mm). We examined 11 factors of rainfall (rainfall amount, rainfall intensity, rainfall kinetic energy, rainfall erosivity and rainfall duration), flood (area-specific sediment yield, runoff depth, peak flow discharge, peak sediment concentration and flood duration) and antecedent land surface (antecedent precipitation) in relation to SDRe. Only the peak sediment concentration significantly correlates with SDRe. Contrary to popular belief, channel scour tends to occur in cases of higher peak sediment concentrations. Because small events also have chances to attain a high sediment concentration, many small events (rainfall depth <20 mm) are characterized by channel scour with an SDRe larger than 1. Such observations can be related to hyperconcentrated flows, which behave quite differently from normal stream flows. Our finding that large events have a nearly constant SDRe is useful for sediment yield predictions in the Loess Plateau and other regions where hyperconcentrated flows are well developed.

  18. Sediment Delivery Ratio of Single Flood Events and the Influencing Factors in a Headwater Basin of the Chinese Loess Plateau

    PubMed Central

    Zheng, Mingguo; Liao, Yishan; He, Jijun

    2014-01-01

    Little is known about the sediment delivery of single flood events although it has been well known that the sediment delivery ratio at the inter-annual time scale is close to 1 in the Chinese Loess Plateau. This study examined the sediment delivery of single flood events and the influencing factors in a headwater basin of the Loess Plateau, where hyperconcentrated flows are dominant. Data observed from plot to subwatershed over the period from 1959 to 1969 were presented. Sediment delivery ratio of a single event (SDRe) was calculated as the ratio of sediment output from the subwatershed to sediment input into the channel. It was found that SDRe varies greatly for small events (runoff depth <5 mm or rainfall depth <30 mm) and remains fairly constant (approximately between 1.1 and 1.3) for large events (runoff depth >5 mm or rainfall depth >30 mm). We examined 11 factors of rainfall (rainfall amount, rainfall intensity, rainfall kinetic energy, rainfall erosivity and rainfall duration), flood (area-specific sediment yield, runoff depth, peak flow discharge, peak sediment concentration and flood duration) and antecedent land surface (antecedent precipitation) in relation to SDRe. Only the peak sediment concentration significantly correlates with SDRe. Contrary to popular belief, channel scour tends to occur in cases of higher peak sediment concentrations. Because small events also have chances to attain a high sediment concentration, many small events (rainfall depth <20 mm) are characterized by channel scour with an SDRe larger than 1. Such observations can be related to hyperconcentrated flows, which behave quite differently from normal stream flows. Our finding that large events have a nearly constant SDRe is useful for sediment yield predictions in the Loess Plateau and other regions where hyperconcentrated flows are well developed. PMID:25389752

  19. Predicting uncertainty in sediment transport and landscape evolution - the influence of initial surface conditions

    NASA Astrophysics Data System (ADS)

    Hancock, G. R.; Coulthard, T. J.; Lowry, J. B. C.

    2016-05-01

    Numerical landscape evolution models were initially developed to examine natural catchment hydrology and geomorphology and have become a common tool to examine geomorphic behaviour over a range of time and space scales. These models all use a digital elevation model (DEM) as a representation of the landscape surface and a significant issue is the quality and resolution of this surface. Here we focus on how subtle perturbations or roughness on the DEM surface can produce alternative model results. This study is carried out by randomly varying the elevations of the DEM surface and examining the effect on sediment transport rates and geomorphology for a proposed rehabilitation design for a post-mining landscape using multiple landscape realisations with increasing magnitudes of random changes. We show that an increasing magnitude of random surface variability does not appear to have any significant effect on sediment transport over millennial time scales. However, the random surface variability greatly changes the temporal pattern or delivery of sediment output. A significant finding is that all simulations at the end of the 10,000 year modelled period are geomorphologically similar and present a geomorphological equifinality. However, the individual patterns of erosion and deposition were different for repeat simulations with a different sequence of random perturbations. The alternative positions of random perturbations strongly influence local patterns of hillslope erosion and evolution together with the pattern and behaviour of deposition. The findings demonstrate the complex feedbacks that occur even within a simple modelled system.

  20. Influence of biogeochemical interactions on metal bioleaching performance in contaminated marine sediment.

    PubMed

    Fonti, Viviana; Dell'Anno, Antonio; Beolchini, Francesca

    2013-09-15

    Bioleaching strategies are still far from finding real applications in sediment clean-up, although metabolic mechanisms governing bioleaching processes have been deeply studied and can be considered well established. In this study, we carried out bioleaching experiments, using autotrophic and heterotrophic acidophilic bacteria strains, and worked with marine sediments characterized by different geochemical properties and metal concentrations and speciations. The solubilization efficiency of the metals was highly variable, with the highest for Zn (40%-76%) and the lowest for Pb (0%-7%). Our data suggest that the role of autotrophic Fe/S oxidizing bacteria is mainly associated with the production and re-cycling of leaching chemical species, mainly as protons and ferric ions. Metal solubilization appears to be more related to establishing environmental conditions that allow each metal or semimetal to remain stable in the solution phase. Thus, the maintenance of acid and oxidative conditions, the chemical behavior in aqueous environment of each metal species and the geochemical characteristics of sediment interact intimately to influence metal solubilization in site-specific and metal-specific way.

  1. Tectonic influence on sedimentation patterns, Upper Ordovician of eastern North America

    SciTech Connect

    Keith, B.D.

    1987-09-01

    The upper part of the Champlainian Series and all of the Cincinnatian Series (both parts of the Upper Ordovician Series on the newly published COSUNA charts) can be divided up into seven time slices; the late part of the Blackriverian Age, Rocklandian, Kirkfieldian, Shermanian, Edenian, Maysvillian Ages, and early part of Richmondian Age. Analysis of the rocks, using these time slices in eastern North America, shows five regional facies packages: (1) clean carbonates, (2) mixed carbonates and terrigenous clastics, (3) shale, (4) terrigenous clastics coarser than shale, and (5) terrigenous clastics prograded over carbonates. The latter is considered a facies because of this style of sedimentation is integral to the Upper Ordovician. Regional tectonic events related to plate collision along the eastern margin of North America had a direct influence on the sedimentation pattern of these facies packages. the extensive clean carbonate platform represented by upper Blackriverian rocks was replaced by wide-spread argillaceous carbonates during Rocklandian, Kirkfieldian, and Shermanian time. Also, by Shermanian time, a linear belt of shale deposition bisected the carbonate platform from the southwest to the northeast. South of this trend, carbonate sedimentation continued essentially without interruption in response to tectonic stability until the end of the Ordovician Period. To the north, the carbonate platform deepened and was later flooded by shale during Edenian and Maysvillian time. Starting during the Maysvillian and continuing into the Richmondian, upwarping and erosion of the Taconic highlands caused large-scale terrigenous clastic progradation over the northeastern part of the platform.

  2. Influence of Sources on Plutonium Mobility and Oxidation State Transformations in Vadose Zone Sediments

    SciTech Connect

    Kaplan,D.; Powell, B.; Duff, M.; Demirkanli, D.; Denham, M.; Fjeld, R.; Molz, F.

    2007-01-01

    Well-defined solid sources of Pu(III) (PuCl3), Pu(IV) (Pu (NO3)4 and Pu (C2O4)2), and Pu(VI) (PuO2(NO3)2) were placed in lysimeters containing vadose zone sediments and exposed to natural weather conditions for 2 or 11 years. The objective of this study was to measure the release rate of Pu and the changes in the Pu oxidation states from these Pu sources with the intent to develop a reactive transport model source-term. Pu(III) and Pu(IV) sources had identical Pu concentration depth profiles and similar Pu release rates. Source release data indicate that PuIV(C2O4)2 was the least mobile, whereas PuVIO2(NO3)2 was the most mobile. Synchrotron X-ray fluorescence (SXRF) revealed that Pu was very unevenly distributed on the sediment and Mn concentrations were too low (630 mg kg-1) and perhaps of the wrong mineralogy to influence Pu distribution. The high stability of sorbed Pu(IV) is proposed to be due to the formation of a stable hydrolyzed Pu(IV) surface species. Plutonium X-ray absorption near-edge spectroscopy (XANES) analysis conducted on sediment recovered at the end of the study from the PuIV(NO3)4- and PuIIICl3-amended lysimeters contained essentially identical Pu distributions: approximately 37% Pu(III), 67% Pu(IV), 0% Pu(V), and 0% Pu(VI). These results were similar to those using a wet chemistry Pu oxidation state assay, except the latter method did not detect any Pu(III) present on the sediment but instead indicated that 93-98% of the Pu existed as Pu(IV). This discrepancy was likely attributable to incomplete extraction of sediment Pu(III) by the wet chemistry method. Although Pu has been known to exist in the +3 oxidation state under microbially induced reducing conditions for decades, to our knowledge, this is the first observation of steady-state Pu(III) in association with natural sediments. On the basis of thermodynamic considerations, Pu(III) has a wide potential distribution, especially in acidic environments, and as such may warrant further

  3. Influence of Zostera marina canopies on unidirectional flow, hydraulic roughness and sediment movement

    NASA Astrophysics Data System (ADS)

    Lefebvre, A.; Thompson, C. E. L.; Amos, C. L.

    2010-09-01

    Seagrasses develop extensive or patchy underwater meadows in coastal areas around the world, forming complex, highly productive ecosystems. Seagrass canopies exert strong effects on water flow inside and around them, thereby affecting flow structure, sediment transport and benthic ecology. The influence of Zostera marina canopies on flow velocity, turbulence, hydraulic roughness and sediment movement was evaluated through laboratory experiments in 2 flumes and using live Z. marina and a mobile sand bed. Profiles of instantaneous velocities were measured and sediment movement was identified upstream, within and downstream of patches of different sizes and shoot density and at different free-stream velocities. Flow structure was characterised by time-averaged velocity, turbulence intensity and Turbulent Kinetic Energy (TKE). When velocity data were available above the canopy, they were fitted to the Law of the Wall and shear velocities and roughness lengths were calculated. When a seagrass canopy was present, three layers were distinguishable in the water column: (1) within canopy represented by low velocities and high turbulence; (2) transition zone around the height of the canopy, where velocities increased, turbulence decreased and TKE was high; and (3) above canopy where velocities were equal or higher than free-stream velocities and turbulence and TKE were lower than below. Shoot density and patch-width influenced this partitioning of the flow when the canopy was long enough (based on flume experiments, at least more than 1 m-long). The enhanced TKE observed at the canopy/water interface suggests that large-scale turbulence is generated at the canopy surface. These oscillations, likely to be related to the canopy undulations, are then broken down within the canopy and high-frequency turbulence takes place near the bed. This turbulence 'cascade' through the canopy may have an important impact on biogeochemical processes. The velocity above the canopy generally

  4. Medium term modelling of coupled hydrodynamics, turbulence and sediment pathways in a region of freshwater influence.

    NASA Astrophysics Data System (ADS)

    Amoudry, Laurent; Brown, Jenny; Souza, Alex; Norman, Danielle; Olsen, Karine

    2014-05-01

    Liverpool Bay, in the northwest of the UK, is a shallow, hypertidal region of freshwater influence. In this region, baroclinic processes significantly affect the residual circulation, which in turn influences the long term transport of sediment. A nested modelling system is implemented to simulate the coupled hydro and sediment dynamics in the bay. We use the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS), which is based on a three-dimensional baroclinic numerical model formulated in spherical polar terrain-following coordinates. The hydrodynamic model solves the three-dimensional, hydrostatic, Boussinesq equations of motion separated into depth-varying and depth-independent parts to allow time splitting between barotropic and baroclinic components. This model is coupled to the General Ocean Turbulence Model (GOTM), to the WAve Model (WAM), and includes state-of-the-art Eulerian and Lagrangian sediment transport models. We implement POLCOMS to Liverpool Bay at a horizontal resolution of approximately 180 m. The bathymetry consists of digitized hydrographic charts combined with LIDAR and multibeam data. Three-dimensional baroclinic effects, river inputs, surface heating and offshore density structure are all considered. Liverpool Bay is subjected to a spring tidal range in excess of 10 m and thus intertidal areas are significant. Wetting and drying algorithms are therefore also implemented. A nesting approach is employed to prescribe offshore boundary conditions for elevations, currents, temperature and salinity. Boundary values are obtained from numerical simulations for the entire Irish and are then used to force the three-dimensional hydrodynamics in the Liverpool Bay domain. Atmospheric forcing consists of hourly wind velocity and atmospheric pressure, and three-hourly cloud cover, humidity and air temperature. We focus here on numerical simulations for a full year, 2008, which is considered to be a typical year for atmospheric

  5. The influence of sample drying and storage conditions on methylmercury determination in soils and sediments.

    PubMed

    Kodamatani, Hitoshi; Maeda, Chihiro; Balogh, Steven J; Nollet, Yabing H; Kanzaki, Ryo; Tomiyasu, Takashi

    2017-04-01

    The separate influences of drying and storage conditions on methylmercury (MeHg) concentrations in soil and sediment samples were investigated. Concentrations of MeHg and total Hg were determined in various soil and sediment samples that had been stored or dried under differing conditions. The influence of drying conditions (oven-drying (40 °C) versus freeze-drying) on MeHg concentrations in marine sediments, river sediments, soils, and paddy field soils was investigated (n = 43). The ratio of the MeHg concentration in oven-dried sub-samples divided by the concentration in freeze-dried sub-samples ranged from 0 to 336%. In order to confirm the production of MeHg during storage in some samples, Hg(2+) was added at 15 mg kg(-1) to a paddy soil, and the sample was then stored at 30 °C. The concentrations of MeHg at 1-h, 1-day, 4-days and 7-days after Hg(2+) spiking were 2.0 ± 0.1, 13.8 ± 1.0, 36.0 ± 5.0, and 24.9 ± 1.6 μg kg(-1) (n = 3), respectively. The concentration of MeHg at 4-days after Hg spiking and sterilizing (121 °C, 30 min) was 1.8 μg kg(-1), similar to the original value. These results indicate that bacterial Hg methylation and MeHg demethylation occurred within days in the soil. In addition, tests of the stability of MeHg in wet and dry samples during storage were also performed. Overall, our results indicate that the best way to preserve MeHg in soil and sediment samples is to freeze the samples immediately after collection, followed subsequently by freeze-drying, grinding, homogenization, and storage of the dry material in cool, dark conditions until analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The influence of volcanic activity on suspended sediment yield of rivers (Kamchatka, Russia)

    NASA Astrophysics Data System (ADS)

    Kuksina, Ludmila

    2014-05-01

    Kamchatka is specific region of suspended sediment yield formation. This fact is particularly connected with active volcanism in the territory. The influence of volcanism on suspended sediment yield characteristics was studied in various time scales - into-diurnal, seasonal and long-term ones. The study of spatial variability of these characteristics reveals the maximum values characterize river basins in zones of strong impact of volcanic eruptions, especially, rivers draining slopes and flanks of active volcanoes. Into-diurnal fluctuations were studied for rivers in volcanic areas. They are characterized by synchronous changes of water flow and turbidity. It's determined by weak erosion-preventive capacity of friable volcanic deposits and big slopes of channels (2.5 - 6.0 %). The maximum of water flow and turbidity is observed at the period between 12 and 6 pm. The air temperature reaches its maximum by that time, and consequently, the intensity of snow melting is also maximum one. The maximum of turbidity advances diurnal maximum of water flow a little, and it's connected with the features of flood wave moving and consecutive maximums of slopes, turbidity, velocity, water flow, and capacity of stream during flush. Into-diurnal fluctuations are determined by complicated and little-studied processes of mass transfer between stream and channel deposits. These processes are connected with into-diurnal changes of stream capacity and water transfer between channel and underflow. As the result water regime is pulsating. Rivers under the influence of volcanic eruptions transport the main amount of sediments during floods which usually occur in summer-autumn period (in the absence of extreme floods in winter-spring period during volcanic eruptions). Combination of maximum snow supply, significant precipitation in warm part of the year and weak erosion-preventive capacity of friable volcanic deposits on volcanoes slopes is the reason of the most intense erosion in this

  7. River-Borne Sediment Exports, Sedimentation Rates, and Influence on Benthos and Leaflitter Breakdown in Southern Caribbean Mangroves (uraba, Colombia)

    NASA Astrophysics Data System (ADS)

    Blanco, J. F.; Taborda, A.; Arroyave, A.

    2011-12-01

    Deposition of river-borne sediments is a major issue in coastal ecosystems worldwide, but no study has been conducted in Neotropical mangroves. Mangroves in the Urabá Gulf (Southern Caribbean coast of Colombia) receive one of the highest sediment loads (<0.10-0.77 x 106 ton yr-1) of the Caribbean region from rivers crossing an extensive banana crop district. Annual sedimentation rates were computed based in monthly samplings (2009-2010) in mangrove fringes across the Turbo River Delta using bottom-fixed 1L-cylinders (n=15). A significant spatial variation (0.04-0.9 ton m-2 yr-1) was observed among sampling stations within the delta, but the highest trapping occurred on river's main channel (2.54 ton m-2 yr-1). Temporal variation was smaller than spatial variation. Monitoring (twenty 1-m2 quadrats x 3 sites x 12 months) of a dominant mangrove-floor gastropod (Neritina virginea) observed a positive increase of density (4-125 ind. m-2: One-way ANOVA: p<0.001) along a sedimentation gradient (monthly means for low and high sedimentation sites: 3-69 kg m-2 yr-1). The role of N. virginea on leaflitter breakdown relative to sedimentation level was experimentally tested in a black mangrove (Avicennia germinans) stand by using 180 wire-mesh cages (15 x 15 x 25 cm) placed on the forest floor as experimental units, to prevent snail and crab access. After clearing existing snails and litter from the muddy bottom, each cage was placed and 1 senescent leaf of A. germinans and 7 snails were introduced (previously weighed) (snail abundance was similar to background densities). Three levels of area-weighed sedimentation rates (1, 3 and 18 g per cage) were daily added to test the impacts of the field-observed sedimentation gradient. The experiment was carried out during one month. Fresh leaf mass was different among treatments during the first week, increasing in proportion to the sedimentation rate probably due to leaf soaking. However, there was no difference in fresh leaf weight

  8. Influence of Geology and Basin Characteristics on Suspended Sediment Yield in Harvested Western Oregon Headwater Streams

    NASA Astrophysics Data System (ADS)

    Bywater-Reyes, S.; Segura, C.; Bladon, K. D.

    2016-12-01

    Suspended sediment is an important regulator of ecologic and geomorphic functions of streams; however, the impact of forest management activities on suspended sediment dynamics relative to natural variability remains largely unknown. We used generalized least squares regression models to investigate how suspended sediment yield (SSY) varied as a function of catchment attributes and harvest treatment for five headwater catchments in the Trask Watershed in western Oregon. Results indicate that sites underlain by the highest percentage of contributing area composed of friable rocks generally produced the greatest SSY per unit discharge (intercept of rating curve, α) compared to those underlain by resistant lithologies. Similarly, the greatest increases in SSY per unit discharge (order of magnitude increase in α) following harvest generally occurred at sites associated with friable geologic units. The impact of forest management activities was secondary to and contingent on catchment setting in influencing SSY variability. Principal component analysis was used to generalize SSY results in terms of basin physiographic variables. This analysis highlighted two groups of sites: those with a low α (lower SSY response per unit discharge) and greater resilience to forest harvest impacts, and those with a high α (higher SSY response per unit discharge) and greater vulnerability to forest harvest impacts. Sites within the high-α group had lower mean relative elevation and slope, higher roughness, and lower connectivity, suggesting greater rates of weathering and sediment supply to headwater streams underlain by friable units in contrast to supply-limited conditions for low-α sites underlain by resistant lithologies. We hypothesize that a similar framework may aid in predicting both overall SSY, as well as susceptibility to forest harvest-related increases in SSY.

  9. Spatial variability of metals in surface water and sediment in the langat river and geochemical factors that influence their water-sediment interactions.

    PubMed

    Lim, Wan Ying; Aris, Ahmad Zaharin; Zakaria, Mohamad Pauzi

    2012-01-01

    This paper determines the controlling factors that influence the metals' behavior water-sediment interaction facies and distribution of elemental content ((75)As, (111)Cd, (59)Co, (52)Cr, (60)Ni, and (208)Pb) in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals' concentration varied among stations. Metal concentrations of water ranged between 0.08-24.71 μg/L for As, <0.01-0.53 μg/L for Cd, 0.06-6.22 μg/L for Co, 0.32-4.67 μg/L for Cr, 0.80-24.72 μg/L for Ni, and <0.005-6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47-30.04 mg/kg for As, 0.02-0.18 mg/kg for Cd, 0.87-4.66 mg/kg for Co, 4.31-29.04 mg/kg for Cr, 2.33-8.25 mg/kg for Ni and 5.57-55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb) were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans.

  10. Recent sediment dynamics in hadal trenches: Evidence for the influence of higher-frequency (tidal, near-inertial) fluid dynamics

    NASA Astrophysics Data System (ADS)

    Turnewitsch, Robert; Falahat, Saeed; Stehlikova, Jirina; Oguri, Kazumasa; Glud, Ronnie N.; Middelboe, Mathias; Kitazato, Hiroshi; Wenzhöfer, Frank; Ando, Kojiro; Fujio, Shinzou; Yanagimoto, Daigo

    2014-08-01

    In addition to high hydrostatic pressure, scarcity of food is viewed as a factor that limits the abundance and activity of heterotrophic organisms at great ocean depths, including hadal trenches. Supply of nutritious food largely relies on the flux of organic-rich particulate matter from the surface ocean. It has been speculated that the shape of hadal trenches helps to ‘funnel' particulate matter into the deeper parts of the trench, leading to sediment ‘focussing' and improved benthic food supply. Here we investigate for five Northwest Pacific trenches the efficiency of sediment focussing by evaluating ratios of measured (sediment-derived) and expected (water-column-derived) sedimentary inventories of the naturally occurring and radioactive particulate-matter tracer 210Pbxs. The sites comprise a broad range of surface-ocean productivity and physical-oceanographic regimes. Across the five trench-axis settings the inventory ratio varies between 0.5 and 4.1, with four trench-axis settings having ratios>1 (sediment focussing) and one trench-axis setting a ratio<1 (sediment winnowing). Although the fluid- and sediment-dynamical forcing behind sediment focussing remains unclear, this study finds evidence for another mechanism that is superimposed on, and counteracts, the focussing mechanism. This superimposed mechanism is related to higher-frequency (tidal, near-inertial) fluid dynamics. In particular, there is evidence for a strong and negative relation between the intensity of propagating internal tides and the extent of sediment focussing in the trench-axis. The relation can be approximated by a power function and the most intense drop in sediment focussing already occurs at moderate internal-tide intensities. This suggests that propagating internal tides may have a subtle but significant influence on particulate-matter dynamics and food supply in hadal trenches in particular, but possibly also in the deep seas in general. A mechanism for the influence of

  11. Influence of Igneous Basement on Deep Sediment Microbial Diversity on the Eastern Juan de Fuca Ridge Flank

    PubMed Central

    Labonté, Jessica M.; Lever, Mark A.; Edwards, Katrina J.; Orcutt, Beth N.

    2017-01-01

    Microbial communities living in deeply buried sediment may be adapted to long-term energy limitation as they are removed from new detrital energy inputs for thousands to millions of years. However, sediment layers near the underlying oceanic crust may receive inputs from below that influence microbial community structure and/or activity. As part of the Census of Deep Life, we used 16S rRNA gene tag pyrosequencing on DNA extracted from a spectrum of deep sediment-basement interface samples from the subsurface of the Juan de Fuca Ridge flank (collected on IODP Expedition 327) to examine this possible basement influence on deep sediment communities. This area experiences rapid sedimentation, with an underlying basaltic crust that hosts a dynamic flux of hydrothermal fluids that diffuse into the sediment. Chloroflexi sequences dominated tag libraries in all sediment samples, with variation in the abundance of other bacterial groups (e.g., Actinobacteria, Aerophobetes, Atribacteria, Planctomycetes, and Nitrospirae). These variations occur in relation to the type of sediment (clays versus carbonate-rich) and the depth of sample origin, and show no clear connection to the distance from the discharge outcrop or to basement fluid microbial communities. Actinobacteria-related sequences dominated the basalt libraries, but these should be viewed cautiously due to possibilities for imprinting from contamination. Our results indicate that proximity to basement or areas of seawater recharge is not a primary driver of microbial community composition in basal sediment, even though fluids diffusing from basement into sediment may stimulate microbial activity. PMID:28824568

  12. Nitrogen exchange across the sediment-water interface after dredging: The influence of contaminated riverine suspended particulate matter.

    PubMed

    Liu, Cheng; Chen, Kaining; Wang, Zhaode; Fan, Chengxin; Gu, Xiaozhi; Huang, Wei

    2017-10-01

    Dredging has been widely implemented in shallow lakes to reduce internal nitrogen (N) loading. The suspended particulate matter (SPM) coming from polluted rivers usually contains high levels of N and ultimately deposits on the dredged sediment surfaces near the river mouth. To study the influence of the riverine SPM on N exchange across the sediment-water interface (SWI) after dredging, a 360-day experiment was carried out comparing un-dredged and dredged sediments from Lake Chaohu, China. Dredged treatments showed a significant increase (p < 0.01) in total N concentrations in the sediments, while the deposition of SPM had little influence on labile NH4(+)-N concentrations. In addition, NH4(+)-N concentrations in pore-water and NH4(+)-N fluxes were significantly lower in dredged than in un-dredged sediments, despite the deposition of SPM. The oxygen production rates and the oxygen penetration depth in the dredged sediments were both higher than those in the un-dredged sediments. The increase of Nitrospira in dredged sediments was consistent with their decreased NH4(+)-N concentrations and fluxes across the SWI. Therefore, the oxidizing condition, increased oxygen production/consumption rates and Nitrospira relative abundance across the SWI were believed to be correlated with the low N exchange rates in dredged sediments. Dredging for reducing internal N loading in a river mouth area is therefore feasible, although the influence of the riverine SPM should be taken into account when aiming to achieve a long-term internal N loading reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China

    PubMed Central

    Wu, Jinglu; Abuduwaili, Jilili; Liu, Wen

    2016-01-01

    Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1) (aluminum, potassium, iron, magnesium, beryllium, etc.) was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2) (calcium and strontium) was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3) included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2) was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed. PMID:27176765

  14. Superfund record of decision (EPA Region 10): Wyckoff/Eagle Harbor Superfund Site, East Harbor Operable Unit, Bainbridge Island, WA, September 1994

    SciTech Connect

    Not Available

    1994-09-29

    The decision document presents the final remedial action for the East Harbor operable unit (East Harbor) of the Wyckoff/Eagle Harbor Superfund site, Bainbridge Island, Kitsap County, Washington. This is the second Record of Decision to be completed for the site. Sediments in the East Harbor are contaminated with polynuclear aromatic hydrocarbons and other hazardous substances. The principal threat is defined as sediments containing free-phase oily contamination. The selected remedy addresses the principal threat and other sediments contaminated at levels which cause significant adverse effects on marine organisms, by combining sediment capping in subtidal areas with monitoring in intertidal areas to confirm the predicted recovery of intertidal sediments through natural processes.

  15. Influence of the phenols on the biogeochemical behavior of cadmium in the mangrove sediment.

    PubMed

    Li, Jian; Liu, Jingchun; Lu, Haoliang; Jia, Hui; Yu, Junyi; Hong, Hualong; Yan, Chongling

    2016-02-01

    Phenols exert a great influence on the dynamic process of Cd in the soil-plant interface. We investigated the influence of phenols on the biogeochemical behavior of cadmium in the rhizosphere of Avicennia marina (Forsk) Vierh. All combinations of four levels of cadmium (0, 1, 2 and 4 mg/kg DW) and two levels of phenol (0 and 15 mg/kg DW) were included in the experimental design. We found that phenols facilitated increasing concentrations of exchangeable cadmium (Ex-Cd), acid volatile sulfide (AVS) and reactive solid-phase Fe (II) in sediments, and iron in plants, but inhibited Cd accumulation in iron plaque and roots. The concentrations of AVS and reactive solid-phase Fe (II) were significantly positively correlated with Cd treatment. As for the biogeochemical behavior of Cd in mangrove sediments, this research revealed that phenols facilitated activation and mobility of Cd. They disturbed the "source-sink" balance of Cd and turned it into a "source", whilst decreasing Cd absorption in A. marina. Additionally, phenols facilitated iron absorption in the plant and alleviated the Fe limit for mangrove plant growth.

  16. The influence of sediments on soft bottom vegetation in inner coastal waters of Mecklenburg-Vorpommern (Germany)

    NASA Astrophysics Data System (ADS)

    Selig, Uwe; Schubert, Manfred; Eggert, Anja; Steinhardt, Tim; Sagert, Sigrid; Schubert, Hendrik

    2007-01-01

    The submersed aquatic vegetation, distinguished as nine different plant communities, was compared with sediment parameters (i.e. mean grain size, sorting level, silt fraction, lime and organic matter as well as content of total carbon, total nitrogen and total phosphorus) in four brackish lagoons in northeastern Germany (southern Baltic Sea). The sediment significantly influenced the distribution of plant communities in the coastal waters. Sorting level and exposition influence the radiation of Ruppia cirrhosa communities. Najas marina stands only grow on sediments with lower phosphorus content. Charophyte stands were found in sediments with smaller mean grain size and higher organic matter and nitrogen contents as plant communities associated with charophytes and without charophytes. However, the dependence of charophytes on low phosphorus levels - as observed in limnic waters - could not be verified in the coastal waters. No significant difference was found at different phosphorus levels between communities with and without charophytes. Myriophyllum spicatum-Potamogeton pectinatus communities - indicators of high degradation in the classification system of coastal waters - were present in a broad spectrum of sediment types, i.e. were not more abundant in habitats with nutrient-rich sediments and muddy sediments.

  17. An estimate of the influence of sediment concentration and type on remote sensing penetration depth for various coastal waters

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.

    1976-01-01

    Under the assumptions of collimated light, a homogenous water column, zero molecular scattering, and constant ratio of volume scattering function to scattering coefficient, estimates of the remote sensing depth parameter, Z90, are made for various coastal waters at 540 nm. Calculations indicate that sediment concentration and type have a strong influence on remote sensing depth when concentrations are below 5 mg/theta. Above 5 mg/theta, the absorption coefficient of the sediments becomes large in comparison to that of water, causing Z90 values to be less than 2 m with only small differences between various sediment types.

  18. [Influence of Vallisneria spiralis on the physicochemical properties of black-odor sediment in urban sluggish river].

    PubMed

    Xu, Kuan; Liu, Bo; Wang, Guo-Xiang; Ma, Jiu-Yuan; Cao, Xun; Zhou, Feng

    2013-07-01

    Using Indoor simulation method, the effect of Vallisneria spiralis on the physicochemical propertise of black and stink sediment was investigated. The surface sediment of urban sluggish river which had been heavily polluted was used as material in the study. The results showed that the redox environment of the sediment was significantly improved by Vallisneria spiralis. During the experiment, the Eh of surface sediment rose from -70 mV to 90 mV. The ferrous content was reduced by 25% in the experiment group while increased by 38% in the control group; the organic matter was decomposed effectively, prevented from natural decomposition to the smelly substances. There was a 3 mm thick greyish yellow oxide layer after 7 days in the experimental group, and the oxide layer gradually thickened over time. The thickness of the oxide layer reached 11 mm at the end of the experiment, and no significant odor was detected. On the contrary, the oxide layer in the control group was only 1 mm thick and the thickness remained unchanged. Meanwhile, an obnoxious odor existed during the whole experiment. The roots of Vallisneria spiralis had significant influence on the porosity of sediment. On one hand, the densification of sediment could be improved by Vallisneria spiralis. On the other hand, Vallisneria spiralis was able to change the state of the surface sediment flows, reduce the erosion of river sediment and inhibit the transfer of black-odor substances, which has a positive ecological meaning.

  19. Human land uses enhance sediment denitrification and N2O production in Yangtze lakes primarily by influencing lake water quality

    NASA Astrophysics Data System (ADS)

    Liu, W.; Yao, L.; Wang, Z.; Xiong, Z.; Liu, G.

    2015-10-01

    Sediment denitrification in lakes alleviates the effects of eutrophication through the removal of nitrogen to the atmosphere as N2O and N2. However, N2O contributes notably to the greenhouse effect and global warming. Human land uses (e.g. agricultural and urban areas) strongly affect lake water quality and sediment characteristics, which, in turn, may regulate lake sediment denitrification and N2O production. In this study, we investigated sediment denitrification and N2O production and their relationships to within-lake variables and watershed land uses in 20 lakes from the Yangtze River basin in China. The results indicated that both lake water quality and sediment characteristics were significantly influenced by watershed land uses. N2O production rates increased with increasing background denitrification rates. Background denitrification and N2O production rates were positively related to water nitrogen concentrations but were not significantly correlated with sediment characteristics and plant community structure. A significant positive relationship was observed between background denitrification rate and percentage of human-dominated land uses (HDL) in watersheds. Structural equation modelling revealed that the indirect effects of HDL on sediment denitrification and N2O production in Yangtze lakes were mediated primarily through lake water quality. Our findings also suggest that although sediments in Yangtze lakes can remove large quantities of nitrogen through denitrification, they may also be an important source of N2O, especially in lakes with high nitrogen content.

  20. Rock-Bound Arsenic Influences Ground Water and Sediment Chemistry Throughout New England

    USGS Publications Warehouse

    Robinson,, Gilpin R.; Ayotte, Joseph D.

    2007-01-01

    The information in this report was presented at the Northeastern Region Geological Society of America meeting held March 11-14, 2007, in Durham, New Hampshire. In the New England crystalline bedrock aquifer, concentrations of arsenic that exceed the drinking water standard of 10 ?g/L occur most frequently in ground water from wells sited in specific metamorphic and igneous rock units. Geochemical investigations indicate that these geologic units typically have moderately elevated whole-rock concentrations of arsenic compared to other rocks in the region. The distribution of ground water wells with As > 5 ?g/L has a strong spatial correlation with specific bedrock units where average whole-rock concentrations of arsenic exceed 1.1 mg/kg and where geologic and geochemical factors produce high pH ground water. Arsenic concentrations in stream sediments collected from small drainages reflect the regional distribution of this natural arsenic source and have a strong correlation with both rock chemistry and the distribution of bedrock units with elevated arsenic chemistry. The distribution of ground water wells with As > 5 ?g/L has a strong spatial correlation with the distribution of stream sediments where concentrations of arsenic exceed 6 mg/kg. Stream sediment chemistry also has a weak correlation with the distribution of agricultural lands where arsenical pesticides were used on apple, blueberry, and potato crops. Elevated arsenic concentrations in bedrock wells, however, do not correlate with agricultural areas where arsenical pesticides were used. These results indicate that both stream sediment chemistry and the solubility and mobility of arsenic in ground water in bedrock are influenced by host-rock arsenic concentrations. Stream sediment chemistry and the distribution of geologic units have been found to be useful parameters to predict the areas of greatest concern for elevated arsenic in ground water and to estimate the likely levels of human exposure to

  1. Influences of organic carbon supply rate on uranium bioreduction in initially oxidizing, contaminated sediment.

    PubMed

    Tokunaga, Tetsu K; Wan, Jiamin; Kim, Yongman; Daly, Rebecca A; Brodie, Eoin L; Hazen, Terry C; Herman, Don; Firestone, Mary K

    2008-12-01

    Remediation of uranium-contaminated sediments through in situ stimulation of bioreduction to insoluble UO2 is a potential treatment strategy under active investigation. Previously, we found that newly reduced U(IV) can be reoxidized under reducing conditions sustained by a continuous supply of organic carbon (OC) because of residual reactive Fe(III) and enhanced U(VI) solubilitythrough complexation with carbonate generated through OC oxidation. That finding motivated this investigation directed at identifying a range of OC supply rates that is optimal for establishing U bioreduction and immobilization in initially oxidizing sediments. The effects of OC supply rate, from 0 to 580 mmol of OC (kg of sediment)(-1) year(-1), and OC form (lactate and acetate) on U bioreduction were tested in flow-through columns containing U-contaminated sediments. An intermediate supply rate on the order of 150 mmol of OC (kg of sediment)(-1) year(-1) was determined to be most effective at immobilizing U. At lower OC supply rates, U bioreduction was not achieved, and U(VI) solubilitywas enhanced by complexation with carbonate (from OC oxidation). At the highest OC supply rate, the resulting highly carbonate-enriched solutions also supported elevated levels of U(VI), even though strongly reducing conditions were established. Lactate and acetate were found to have very similar geochemical impacts on effluent U concentrations (and other measured chemical species), when compared at equivalent OC supply rates. While the catalysts of U(VI) reduction to U(IV) are presumably bacteria, the composition of the bacterial community,the Fe-reducing community, and the sulfate-reducing community had no direct relationship with effluent U concentrations. The OC supply rate has competing effects of driving reduction of U(VI) to low-solubility U(IV) solids, as well as causing formation of highly soluble U(VI)-carbonato complexes. These offsetting influences will require careful control of OC supply rates

  2. Coastal marsh degradation: modeling the influence of vegetation die-off patterns on flow and sedimentation

    NASA Astrophysics Data System (ADS)

    Schepers, Lennert; Wang, Chen; Kirwan, Matthew; Belluco, Enrica; D'Alpaos, Andrea; Temmerman, Stijn

    2014-05-01

    erosion, which may explain their lower surface elevation. Therefore the establishment of marsh plants will be unfavorable. So far, however, this hypothesis has not been verified. In order to investigate the influence of these different types of pool patterns on spatial flow and sedimentation patterns, we used an existing hydrodynamic and sediment transport model (Delft3D) that has been calibrated and validated against field data on tidal marsh flow and sedimentation. The model reproduces the bio-geomorphologic effects of complete vegetation removal, but different pool patterns have not been studied until now. By simulating different pool patterns, we are able to verify our hypothesis regarding elevation changes and marsh recovery potential in degraded marsh pools. This highlights the importance of bio-geomorphologic feedbacks for marsh degradation and recovery.

  3. Influences of Organic Carbon Supply Rate on Uranium Bioreduction in Initially Oxidizing, Contaminated Sediment

    SciTech Connect

    Tokunaga, Tetsu K.; Wan, Jiamin; Kim, Yongman; Daly, Rebecca A.; Brodie, Eoin L.; Hazen, Terry C.; Herman, Don; Firestone, Mary K.

    2008-06-10

    Remediation of uranium (U) contaminated sediments through in-situ stimulation of bioreduction to insoluble UO{sub 2} is a potential treatment strategy under active investigation. Previously, we found that newly reduced U(IV) can be reoxidized under reducing conditions sustained by a continuous supply of organic carbon (OC) because of residual reactive Fe(III) and enhanced U(VI) solubility through complexation with carbonate generated through OC oxidation. That finding motivated this investigation directed at identifying a range of OC supply rates that is optimal for establishing U bioreduction and immobilization in initially oxidizing sediments. The effects of OC supply rate, from 0 to 580 mmol OC (kg sediment){sup -1} year{sup -1}, and OC form (lactate and acetate) on U bioreduction were tested in flow-through columns containing U-contaminated sediments. An intermediate supply rate on the order of 150 mmol OC (kg sediment){sup -1} year{sup -1} was determined to be most effective at immobilizing U. At lower OC supply rates, U bioreduction was not achieved, and U(VI) solubility was enhanced by complexation with carbonate (from OC oxidation). At the highest OC supply rate, resulting highly carbonate-enriched solutions also supported elevated levels of U(VI), even though strongly reducing conditions were established. Lactate and acetate were found to have very similar geochemical impacts on effluent U concentrations (and other measured chemical species), when compared at equivalent OC supply rates. While the catalysts of U(VI) reduction to U(IV) are presumably bacteria, the composition of the bacterial community, the Fe reducing community, and the sulfate reducing community had no direct relationship with effluent U concentrations. The OC supply rate has competing effects of driving reduction of U(VI) to low solubility U(IV) solids, as well as causing formation of highly soluble U(VI)-carbonato complexes. These offsetting influences will require careful control of OC

  4. Influence of sediment permeability and mineral composition on organic matter degradation in three sediments from the Gulf of Aqaba, Red Sea

    NASA Astrophysics Data System (ADS)

    Rasheed, Mohammed; Badran, Mohammad I.; Huettel, Markus

    2003-05-01

    In order to investigate the influence of sediment physical and chemical characteristics on the degradation of deposited organic matter, decomposition in three sediments from the Gulf of Aqaba (Red Sea) that differ in permeability and mineral composition were compared. Freeze-dried Spirulina was added to coarse carbonate and silicate sands from a shallow nearshore region and silt-clay sediment from the deeper center region of the Gulf incubated in laboratory chambers. The stirring in the chambers caused higher solute exchange in the coarse permeable sands relative to the fine less permeable silt due to the generation of advective fluid exchange between the sediment and overlying water. This enhanced exchange increased the decomposition rates of organic matter in the incubated sands. The decomposition rates of total organic carbon in the permeable carbonate (3.0 mg C m -2 d -1) and silicate sands (2.0 mg C m -2 d -1) exceeded that in the fine-grained sediment (1.4 mg C m -2 d -1). Oxygen consumption in the coarse sands was 3-fold higher than in the silt-clay sediment, with highest rates in the carbonate sand. In carbonate and silicate sands of the same grain size, the carbonate sediment was more permeable than the silicate, resulting in 1.4-fold higher fluid exchange rates and 1.4-fold larger sedimentary organic matter mineralization rates. An in situ experiment comparing trapping efficiencies in carbonate and silicate sands showed that the higher fluid exchange rate in the carbonate sand results in larger filtration rates and a faster accumulation of particulate organic matter from the boundary layer. These experiments demonstrate that with respect to sedimentary mineralization rates, higher transport rates in permeable coarse sediments can outweigh the effect of a higher specific surface area in fine-grained silt sediments. In permeable sands, however, the higher specific surface area and fluid exchange in biogenic carbonate sands result in higher mineralization

  5. Ontonagon Harbor Operation and Maintenance Activities. Lake Superior.

    DTIC Science & Technology

    1975-08-01

    2.460 Natural Areas 13 2.500 Future Environmental Setting Without the Project 1z.. 3.000 RELATIONSHIP OF THE HARBOR TO FUTURE LAND USE 14 4.000...Continued) Paragraph Page 6.000 ALTERNATIVES TO THE PROPOSED ACTION 6.100 No Project 22 7.000 RELATIONSHIP BETWEEN SHORT-TERM USES OF NATURAL ...the realization that 50 percent of the sediment dredged annually from Ontonagon Harbor was of a polluted nature , alternative measures of disposal were

  6. The New Bedford Harbor Superfund Site Long Term ...

    EPA Pesticide Factsheets

    Background. New Bedford Harbor (NBH), located in southeastern Massachusetts, was designated as a marine Superfund site in 1983 due to sediment contamination by polychlorinated biphenyls (PCBs). Based on risks to human health and the environment, the first two phases of the site cleanup involved dredging PCB-contaminated sediments from the harbor. Therefore, a long-term monitoring program (LTM) was developed to measure spatial and temporal chemical and biological changes in sediment, water, and biota to assess the effects and effectiveness of the remedial activities. Approach. A systematic, probabilistic sampling design was used to select approximately 70 sediment sampling stations. Sediment was collected at each station and chemical (e.g., PCBs, metals), physical (e.g., grain size), and biological (e.g., benthic community) measurements were conducted on all samples. There have been six sample collections to date: 1993-baseline, 1995-post hot spot removal, 1999-prior to full scale dredging, and then at 5 year intervals: 2004, 2009, and 2014. Mussel (Mytilus edulis) bioaccumulation has also been measured twice yearly. Results. There is a decreasing spatial gradient in sediment PCB concentrations from the northern boundary (upper harbor) to the southern boundary (outer harbor) of the site. Along this same transect, there is an increase in biological condition (e.g., benthic community diversity). Temporally, the contaminant and biological gradients have been

  7. The New Bedford Harbor Superfund Site Long Term ...

    EPA Pesticide Factsheets

    Background. New Bedford Harbor (NBH), located in southeastern Massachusetts, was designated as a marine Superfund site in 1983 due to sediment contamination by polychlorinated biphenyls (PCBs). Based on risks to human health and the environment, the first two phases of the site cleanup involved dredging PCB-contaminated sediments from the harbor. Therefore, a long-term monitoring program (LTM) was developed to measure spatial and temporal chemical and biological changes in sediment, water, and biota to assess the effects and effectiveness of the remedial activities. Approach. A systematic, probabilistic sampling design was used to select approximately 70 sediment sampling stations. Sediment was collected at each station and chemical (e.g., PCBs, metals), physical (e.g., grain size), and biological (e.g., benthic community) measurements were conducted on all samples. There have been six sample collections to date: 1993-baseline, 1995-post hot spot removal, 1999-prior to full scale dredging, and then at 5 year intervals: 2004, 2009, and 2014. Mussel (Mytilus edulis) bioaccumulation has also been measured twice yearly. Results. There is a decreasing spatial gradient in sediment PCB concentrations from the northern boundary (upper harbor) to the southern boundary (outer harbor) of the site. Along this same transect, there is an increase in biological condition (e.g., benthic community diversity). Temporally, the contaminant and biological gradients have been

  8. Hard substrate in the deep ocean: How sediment features influence epibenthic megafauna on the eastern Canadian margin

    NASA Astrophysics Data System (ADS)

    Lacharité, Myriam; Metaxas, Anna

    2017-08-01

    Benthic habitats on deep continental margins (> 1000 m) are now considered heterogeneous - in particular because of the occasional presence of hard substrate in a matrix of sand and mud - influencing the distribution of megafauna which can thrive on both sedimented and rocky substrates. At these depths, optical imagery captured with high-definition cameras to describe megafauna can also describe effectively the fine-scale sediment properties in the immediate vicinity of the fauna. In this study, we determined the relationship between local heterogeneity (10-100 sm) in fine-scale sediment properties and the abundance, composition, and diversity of megafauna along a large depth gradient (1000-3000 m) in a previously-unexplored habitat: the Northeast Fan, which lies downslope of submarine canyons off the Gulf of Maine (northwest Atlantic). Substrate heterogeneity was quantified using a novel approach based on principles of computer vision. This approach proved powerful in detecting gradients in sediment, and sporadic complex features (i.e. large boulders) in an otherwise homogeneous environment because it characterizes sediment properties on a continuous scale. Sediment heterogeneity influenced megafaunal diversity (morphospecies richness and Shannon-Wiener Index) and community composition, with areas of higher substrate complexity generally supported higher diversity. However, patterns in abundance were not influenced by sediment properties, and may be best explained by gradients in food supply. Our study provides a new approach to quantify fine-scale sediment properties and assess their role in shaping megafaunal communities in the deep sea, which should be included into habitat studies given their potential ecological importance.

  9. Influence of sediment metal spiking procedures on copper bioavailability and toxicity in the estuarine bivalve Indoaustriella lamprelli.

    PubMed

    Hutchins, Colin M; Teasdale, Peter R; Lee, Shing Y; Simpson, Stuart L

    2009-09-01

    The effect of three methods for spiking sediments with Cu on the reburial behavior, mortality, and tissue Cu accumulation of a lucinid bivalve (Indoaustriella lamprelli) and the influence of the bivalve on the sediment geochemistry were investigated. Methods used to create Cu concentration gradients were direct spiking with and without pH adjustment to pH 7 and also dilution of sediment, previously spiked with Cu and adjusted to pH 7, using a low-Cu sediment (known to produce the lowest pore-water Cu concentrations). The presence of the bivalve within Cu-spiked sediment increased the flux of Cu and Mn to overlying waters at high Cu concentrations (550 microg/g). Bivalve behavioral response, metal accumulation, and mortality varied with the method by which Cu was spiked. In direct Cu-spiked sediment, the bivalves were inactive at concentrations of 550 and 1,100 microg/g, with mortality induced in sediment spiked with 1,100 microg/g (pH 6.5-7.1). Complete bivalve inactivity was observed only at 1,100 microg/g in direct Cu-spiked sediment with pH adjustment, whereas percentage reburial was reduced to 30% at 1,100 microg/g for sediment prepared by the dilution method. Relative reburial rates in the three spiked sediment types (direct < direct pH-7 < dilution) were proportional to dissolved Cu concentrations in the overlying water. Bivalve reburial, in addition to the method of Cu addition, affected tissue Cu accumulation. Inhibition of bivalve reburial decreased the amount of accumulated Cu, confounding relationships between tissue Cu and pore water, overlying water, or extractable metal fractions.

  10. Great Lakes Harbors Study

    DTIC Science & Technology

    1966-11-01

    Locally.assigned Library of Congress number: HE396 S25 U55 Nj 19. KEY WORDS (Continue on reverse side if necessary and identify by block number) 1. HARBORS 2... WATER TRANSPORTATION 3. ECONOMIC ANALYSIS 4. GREAT LJAKES - 20. ABSTRACT (Continue on ie.er.se side It necesaty nd identify by blocA number) Harbor...Scope 2 DESCRIPTION AND ECONOMIC DEVELOPMENT 3 Great Lakes-St. Lawrence Navigation System 2 4 Navigation Season 3 5 Water Levels 4 6 Tributary Area 6

  11. Metagenomic analysis of sediments under seaports influence in the Equatorial Atlantic Ocean.

    PubMed

    Tavares, Tallita Cruz Lopes; Normando, Leonardo Ribeiro Oliveira; de Vasconcelos, Ana Tereza Ribeiro; Gerber, Alexandra Lehmkuhl; Agnez-Lima, Lucymara Fassarella; Melo, Vânia Maria Maciel

    2016-07-01

    Maritime ports are anthropogenic interventions capable of causing serious alterations in coastal ecosystems. In this study, we examined the benthic microbial diversity and community structure under the influence of two maritime ports, Mucuripe (MUC) and Pecém (PEC), at Equatorial Atlantic Ocean in Northeast Brazil. Those seaports differ in architecture, time of functioning, cargo handling and contamination. The microbiomes from MUC and PEC were also compared in silico to 11 other globally distributed marine microbiomes. The comparative analysis of operational taxonomic units (OTUs) retrieved by PCR-DGGE showed that MUC presents greater richness and β diversity of Bacteria and Archaea than PEC. In line with these results, metagenomic analysis showed that MUC and PEC benthic microbial communities share the main common bacterial phyla found in coastal environments, although can be distinguish by greater abundance of Cyanobacteria in MUC and Deltaproteobacteria in PEC. Both ports differed in Archaea composition, being PEC port sediments dominated by Thaumarchaeota. The microbiomes showed little divergence in their potential metabolic pathways, although shifts on the microbial taxonomic signatures involved in nitrogen and sulphur metabolic pathways were observed. The comparative analysis of different benthic marine metagenomes from Brazil, Australia and Mexico grouped them by the geographic location rather than by the type of ecosystem, although at phylum level seaport sediments share a core microbiome constituted by Proteobacteria, Cyanobacteria, Actinobacteria, Tenericuteres, Firmicutes, Bacteriodetes and Euryarchaeota. Our results suggest that multiple physical and chemical factors acting on sediments as a result of at least 60years of port operation play a role in shaping the benthic microbial communities at taxonomic level, but not at functional level.

  12. Influence of Shimada Seamount on sediment composition in the eastern tropical North Pacific

    USGS Publications Warehouse

    Dean, W.E.; Gardner, J.V.; Nancy, L P.

    1989-01-01

    Shimada Seamount is a large, young volcanic edifice in the east-central Pacific that is not associated with any active spreading center or known hot spot. The sediments on the abyssal plain surrounding Shimada Seamount consist of pelagic clay with ferromanganese micronodules and zeolites. The pelagic clay is mostly barren of microfossils except for a few occurrences of highly corroded specimens of Radiolaria and diatoms. Eolian terrigenous material is the dominant component of the pelagic clay to a depth of at least 8 m below sea floor, with minor contributions from volcanic debris and hydrothermal and hydrogenous sources. The average amount of basaltic debris is only 0.25%, but concentrations are as high as 10% in some samples. The average hydrothermal component (metalliferous sediment) is 8.8% with a maximum of about 13% at 7.5 m below sea floor in one core. The hydrogenous component, mostly as ferromanganese micronodules, averages 4.1% with a maximum of 5.6%. There is no calcareous biogenic debris and essentially no siliceous biogenic debris. In the past, a decrease in hydrothermal components through time may have been the result of a decrease in relative importance of hydrothermal influences, or an increase in the flux of terrigenous debris transported by the northeast trade winds. Because volcanic activity is still active on Shimada Seamount, or has been in the recent past, the observed increase in relative abundance of terrigenous components probably was the result of increased wind transport and not decreased hydrothermal activity. Shimada Seamount may be an important local source of metalliferous sediment in the eastern equatorial North Pacific, and may have been an even more important source in the past. ?? 1989.

  13. Influence of fluvial environments on sediment archiving processes and temporal pollutant dynamics (Upper Loire River, France).

    PubMed

    Dhivert, E; Grosbois, C; Rodrigues, S; Desmet, M

    2015-02-01

    Floodplains are often cored to build long-term pollutant trends at the basin scale. To highlight the influences of depositional environments on archiving processes, aggradation rates, archived trace element signals and vertical redistribution processes, two floodplain cores were sampled near in two different environments of the Upper Loire River (France): (i) a river bank ridge and (ii) a paleochannel connected by its downstream end. The base of the river bank core is composed of sandy sediments from the end of the Little Ice Age (late 18th century). This composition corresponds to a proximal floodplain aggradation (<50 m from the river channel) and delimits successive depositional steps related to progressive disconnection degree dynamism. This temporal evolution of depositional environments is associated with mineralogical sorting and variable natural trace element signals, even in the <63-μm fraction. The paleochannel core and upper part of the river bank core are composed of fine-grained sediments that settled in the distal floodplain. In this distal floodplain environment, the aggradation rate depends on the topography and connection degree to the river channel. The temporal dynamics of anthropogenic trace element enrichments recorded in the distal floodplain are initially synchronous and present similar levels. Although the river bank core shows general temporal trends, the paleochannel core has a better resolution for short-time variations of trace element signals. After local water depth regulation began in the early 1930s, differences of connection degree were enhanced between the two cores. Therefore, large trace element signal divergences are recorded across the floodplain. The paleochannel core shows important temporal variations of enrichment levels from the 1930s to the coring date. However, the river bank core has no significant temporal variations of trace element enrichments and lower contamination levels because of a lower deposition of

  14. Influence of Rock Strength on Landscape Evolution and Sediment Provenance Records

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Whipple, K. X.; Yanites, B.

    2014-12-01

    Detrital minerals within the stratigraphic record provide key constraints for a range of geologic problems, including the first order tectonic setting of basins, structural histories within orogens, changes in climate, and major drainage network reorganizations. Numerous provenance techniques exist for linking detrital minerals to their source areas, but the majority of these methods share an underlying assumption that sediment delivered to a basin is a representative sample of the bedrock geology of the source area. Satisfying this assumption requires that sediment production rates, i.e. erosion rates, of a source area are uniform throughout. In detail, erosion rates within a source area vary as a function of patterns of landscape evolution dictated by rock erodibility, climate, and relative uplift rate, thus long-term and transient biasing of sediment provenance records is expected. Biases associated with landscape evolution in response to changes in climate, tectonics, or strength of exposed rock can last 10s Myr. Previous work recognized a potential influence of differential erosion on provenance records, but the relative importance of this effect has proven difficult to quantify with field data. To address this, we are using a modified version of the CHILD landscape evolution model (LEM), which supports numerous lithologies with different erodibilities within a landscape. We perform a sensitivity analysis on the relative influence of rock strength and changes in climate or uplift rate on provenance records. We focus on U-Pb detrital zircon records because these data have seen wide adoption as a provenance tool and the refractory nature of zircon makes them less likely to be influenced by chemical weathering effects that are beyond the scope of this work. We plan to test several scenarios including variations in rock erodibility and temporal changes in climate or uplift rate. We will then use results from the LEM to calculate erosion rates from different

  15. Varved sediments from Lake Czechowskie (Poland) reveal gradual increase in Atlantic influence during the Holocene

    NASA Astrophysics Data System (ADS)

    Ott, Florian; Brauer, Achim; Słowiński, Michał; Wulf, Sabine; Putyrskaya, Victoria; Plessen, Birgit; Błaszkiewicz, Miroslaw

    2015-04-01

    Detailed micro-facies and geochemical analyses have been carried out for the predominantly varved Holocene sediment record of Lake Czechowskie (north-central Poland). The chronology has been established by a multiple dating approach comprising varve counting, AMS 14C dating, 137Cs activity concentration measurements and tephrochronology. The combination of independent dating techniques revealed well-constrained time scales even in phases lacking annual laminations and allows reliable high-resolution archive synchronization. Quantitative (varve thickness variations) and qualitative (sublayer structure) varve parameters as well as geochemical composition have been obtained to gain a comprehensive view of climatic and environmental evolution during the last 11500 years in northern Poland. Five major sedimentological changes have been identified, encompassing transitions from varved to non-varved sediments (and vice versa) at 10.100 and 7.300 cal a BP, respectively, changes in general varve pattern at 6.500 and 4.200 cal a BP and distinct increase of varve thickness accompanied by increased annual variability since 2.800 cal a BP. These changes reflect large-scale reorganization of the climate system throughout the Holocene with increasing influences of the North Atlantic climate system in Poland. Moreover, the observed changes suggest different thresholds and trigger mechanisms over the investigated time period. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analyses - ICLEA - of the Helmholtz Association, grant number VH-VI-415.

  16. Uranium release from sediment to groundwater: influence of water chemistry and insights into release mechanisms.

    PubMed

    Alam, Md Samrat; Cheng, Tao

    2014-08-01

    Uranium (U) contamination in groundwater often results from natural geochemical processes such as mineral dissolution and desorption of adsorbed U from mineral surface. Although U adsorption and U mineral dissolution have been extensively studied, current knowledge of minerals and water chemistry conditions that control U release in uncontaminated soil and aquifers is still limited. Identification of these minerals and the knowledge of how water chemistry conditions influence U release is critical to better understand, predict, and manage geogenic U contamination in soil and groundwater. The objective of this study is to determine the extent and mechanisms of U release from a heterogeneous natural sediment under water chemistry conditions relevant to natural soil water and groundwater. A sediment sample was collected and characterized by XRD, SEM-EDX and extraction methods, and examined using laboratory leaching experiments. Our results show that Fe-Mn (oxy)hydroxides and silicate minerals are the major U hosting minerals, and a substantial fraction of U exists as adsorbed ions on minerals. We also found that U release is controlled by a number of interactive processes including dissolution of U-bearing minerals, U desorption from mineral surface, formation of aqueous U complexes, and reductive precipitation of U. Results from this study shed light on the important geochemical reactions that need be considered for developing a conceptual model that predicts U contamination in subsurface environment. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Influence of environmental factors on denitrification in sediment contaminated with JP-4 jet fuel

    USGS Publications Warehouse

    Bradley, Paul M.; Aelion, C. Marjorie; Vroblesky, Don A.

    1992-01-01

    In 1975, the loss of approximately 83,000 gallons of JP-4 grade jet fuel resulted in contamination of the shallow aquifer near North Charleston, South Carolina. To identify those factors likely to influence microbial activity under denitrifying conditions, we examined the fate of amended NO3, the effect of pH, NO3, and PO4 on denitrification, and the variability of denitrification in sediments collected at the site. Denitrification (N2O-N production) accounted for 98% of the depletion of NO3-N under anaerobic conditions. Both carbon mineralization and denitrification rates increased asymptotically with increasing NO3 to a maximum at approximately 1 mM NO3. Addition of up to 1 mM PO4 did not significantly increase N2O and CO2 production. Denitrification rates were at least 38% lower at pH = 4 than observed at pH = 7. Comparison of samples with differing degrees of hydrocarbon contamination indicated that at least a tenfold variation in sediment denitrification occurs at the North Charleston site.

  18. Dioxin Chronology and Fluxes in Sediments of the Houston Ship Channel, Texas: Influences of Non-steady State Sediment Transport and Total Organic Carbon

    NASA Astrophysics Data System (ADS)

    Yeager, K.; Santschi, P.; Raifai, H.; Suarez, M.; Brinkmeyer, R.; Hung, C.; Schindler, K.; Andres, M.; Weaver, E.

    2007-05-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are persistent contaminants that bio-accumulate and pose serious risks to biota and humans. The primary objective of this study was to determine the history and mechanisms of dioxin accumulation in sediments of the Houston Ship Channel (HSC) using analytical data on natural and anthropogenic radionuclides (7Be, 137Cs and 210Pb) and dioxins. Results showed that present-day sedimentary dioxin accumulation rates are orders of magnitude higher than atmospheric inputs to the HSC, as determined from a wetland sediment core (FW1) and direct measurements. Most stations showed dioxin peaks in the near surface, indicating continuing inputs despite federal regulations. Stations with high dioxin inventories (11270 > 11193 > 16499 > 15979 > 11261) reflect accentuated accumulation in the HSC as one moves west towards Buffalo Bayou (11270, 15979), at the confluence of the HSC and the San Jacinto River (11261) and upstream in the San Jacinto River (11193). While station 11270 had the highest dioxin inventory, and nearby station 11261 had the highest sediment accumulation rates and dioxin fluxes, present-day dioxin fluxes at 11270 are less than average fluxes and inventories for station 11261 are less than average inventories, for all sites. These results support the interpretation that the HSC is influenced by episodic sediment resuspension, erosion and lateral transport processes driven by tides, wind, shipping and dredging, which can cause intermittently high accumulations of dioxins.

  19. Influence of Sediment Transport on Formation of Sandbars in Drainage Canals during Floods

    NASA Astrophysics Data System (ADS)

    Mukai, Akie; Taruya, Hiroyuki; Tanaka, Yoshikazu; Naka, Tatsuo

    Sediment of drainage canals plays significant roles for aquatic plant rooting, fish spawning and invertebrate habitats. In steep areas, it is difficult to maintain the sediment during floods because water flows rapidly. Fast flowing water causes sediment loss and habitat loss through intense sediment transport. Therefore, we installed spur dikes in field drainage canals to control sediment transport and form sandbars to provide habitats for aquatic organisms. The results showed that sandbars were formed by controlling the sediment transport and the process of sandbar formation depended on the magnitude of flood discharge. When the flood discharge was small, the sediment was washed out between the spur dikes, and distinct sandbars were not formed except in areas aquatic plants. When the flood discharge was large, the sediment accumulated between the spur dikes, and sandbars were clearly formed. Without spur dikes, most sediment was flushed away by flood discharges. Consequently, spur dikes facilitate an increase in invertebrate populations by establishing sandbars for habitats.

  20. Influence of ignited sediments on external phosphorus adsorption and sedimentary phosphorus forms.

    PubMed

    Zhu, PeiYing; Li, DaPeng; Huang, Yong; Li, Yong

    2017-08-15

    Phosphorus (P) adsorpted by sediments, when covered by and mixed with ignited sediments from Meiliang Bay in Tai Lake, was analyzed in the laboratory. Potassium dihydrogen phosphate (KH2PO4) was added to the parallel experimental units to simulate periodic external P input. Based on the Langmuir model, the sediments after ignition had a greater Smax (maximum P adsorption), a lower equilibrium phosphorus concentration at zero adsorption (EPC0), and a lower degree of phosphorus saturation in comparison with sediments without ignition. This was confirmed by the variation in the dissolved inorganic phosphorus in the overlying water. When sediments were mixed with or covered by the ignited sediments, 5.985 and 5.978 mg of input P disappeared from the overlying water, respectively. However, when the sediments were mixed with the ignited sediments, 84.18% of the input P was converted to HCl-P, whereas when they were covered by the ignited sediments, sedimentary P was released, mainly from Fe/Al-P (up to 87.50%). This was attributed to differences in the microenvironments where less-intense anaerobic conditions were formed in the mixed sediments than in the sediments covered by the ignited sediments. This suggests that the injection of ignited sediments into existing sediments enhances their P adsorption and retention. It is favor of the control of the eutrophication with a simple technology.

  1. Loki's Castle: A sediment-influenced hydrothermal vent field at the ultra-slow spreading Arctic Mid-Ocean Ridge

    NASA Astrophysics Data System (ADS)

    Baumberger, T.; Frueh-Green, G. L.; Pedersen, R.; Thorseth, I. H.; Lilley, M. D.; Moeller, K.

    2010-12-01

    The chemical composition as well as the stable and radiogenic isotope signatures of hydrothermal fluids from the Loki’s Castle vent field, located at the Mohns-Knipovich bend in the Norwegian-Greenland Sea (73°N), are substantially different from sediment-starved mid-ocean ridge hydrothermal systems. Geochemical studies of the hydrothermal vent fluids and the adjacent rift valley sediments provide insights into the influence of sediments on the hydrothermal fluid composition and provide constraints on acting redox conditions. Additionally, they reflect the degree of fluid-rock-sediment interaction at this arctic hydrothermal vent field. Here we present an overview of the geochemical characteristics of the hydrothermal and sedimentary components at Loki’s Castle, obtained during expeditions in 2008, 2009 and 2010, with emphasis on the stable and radiogenic isotope signatures. We compare these data with other sediment-influenced and sediment-starved mid-ocean ridge hydrothermal systems. The hydrothermal vent fluids are characterized by a pH of ˜ 5.5 and by elevated concentrations of methane, hydrogen and ammonia, which reflect a sedimentary contribution. δ13CDIC (dissolved inorganic carbon) are depleted relative to mantle carbon values, consistent with an organic carbon input. The δ18OH2O values of the vents fluids are enriched compared to background bottom seawater, whereas the δD values are not. 87Sr/86Sr ratios are more radiogenic than those characteristic of un-sedimented mid-ocean ridge vent fluids. S-isotope data reflect mixing of a MORB source with sulphide derived from reduced seawater sulphate. To document the background sediment input of the ridge system, short gravity cores and up to 18 m long piston cores were recovered from various localities in the rift valley. The pore-fluid isotope chemistries of the sediments show vertical gradients that primarily reflect diagenesis and degradation of organic matter. The vertical gradient is locally enhanced

  2. Sediments influence accumulation of two macroalgal species through novel but differing interactions with nutrients and herbivory

    NASA Astrophysics Data System (ADS)

    Clausing, Rachel J.; Bittick, Sarah Joy; Fong, Caitlin R.; Fong, Peggy

    2016-12-01

    Despite increasing concern that sediment loads from disturbed watersheds facilitate algal dominance on tropical reefs, little is known of how sediments interact with two primary drivers of algal communities, nutrients and herbivory. We examined the effects of sediment loads on the thalli of two increasingly abundant genera of macroalgae, Galaxaura and Padina, in a bay subject to terrestrial sediment influx in Mo'orea, French Polynesia. Field experiments examining (1) overall effects of ambient sediments and (2) interacting effects of sediments (ambient/removal) and herbivores (caged/uncaged) demonstrated that sediments had strong but opposite effects on both species' biomass accumulation. Sediment removal increased accumulation of Padina boryana Thivy 50% in the initial field experiment but had no effect in the second; rather, in a novel interaction, herbivores overcompensated for increases in tissue nutrient stores that occurred with sediments loads, likely by preferential consumption of nutrient-rich meristematic tissues. Despite negative effects of sediments on biomass, Padina maintained rapid growth across treatments in both experiments. In contrast, positive growth in Galaxaura divaricata Kjellman only occurred with ambient sediment loads. In mesocosm experiments testing interactions of added nutrients and sediments on growth, Galaxaura grew at equivalent rates with sediments (collected from thalli on the reef) as with additions of nitrate and phosphate, suggesting sediments provide a nutrient subsidy. For Padina, however, the only effect was a 50% reduction in growth with sediment. Overall, retention of thallus sediments creates a positive feedback that Galaxaura appears to require to sustain net growth, while Padina merely tolerates sediments. These results indicate that sediments can modify nutrient and herbivore control of algae in ways that differ among species, with the potential for strong and unexpected effects on the abundance and composition of

  3. Influence of a salt marsh plant (Halimione portulacoides) on the concentrations and potential mobility of metals in sediments.

    PubMed

    Almeida, C Marisa R; Mucha, Ana P; Bordalo, A A; Vasconcelos, M Teresa S D

    2008-09-15

    Influence of Halimione portulacoides, commonly found in temperate salt marshes, on sediment metal contents, speciation and potential mobility in case of sediment re-suspension was evaluated. Both colonized and non-colonized sediments were studied for total Cd, Cu, Pb and Zn contents and metal fraction exchangeable to water collected in situ. Sediment elutriates, prepared with water collected from each site, were used to simulate a sediment re-suspension phenomenon. As the characteristics and degree of contamination of sediments may influence system behaviour, salt marshes of two Portuguese estuaries, Cavado (NW coast) and Sado (SW coast), were studied. Cu, Pb and Zn contents higher than ERL (quality guideline, effect range-low) were observed, indicating potential risks for living organisms. Strong Cu-complexing organic ligands, also determined in both water and elutriates, were higher in rhizosediment elutriates, at concentrations similar, or even higher, to those of Cu. Such ligands condition metals speciation in the water column and probably also metal bioavailability. From rhizosediment significant amounts of Cu and Zn were transferred to the aqueous phase, concentrations 2-8 times higher than concentrations present in water. In contrast, elutriates of non-colonized sediment removed metals from water, Cu and Zn levels in elutriates being 2-6 times lower than initial ones. Cd and Pb levels in water and elutriates were not measurable in most cases. Results clearly indicate that metals potential solubility in the rhizosphere of plants was markedly higher than that in the surrounding sediment. The obtained results indicated that H. portulacoides presence (and probably other salt marsh plants) may cause a marked increase in metals concentrations in dissolved phase (pore water or even water column if rhizosediment is re-suspended). As salt marsh plants may be abundant in temperate and subtropical estuaries and costal lagoons, this phenomenon should not be disregard in

  4. Channel evolution and hydrologic variations in the Colorado River basin: Factors influencing sediment and salt loads

    NASA Astrophysics Data System (ADS)

    Gellis, Allen; Hereford, Richard; Schumm, S. A.; Hayes, B. R.

    1991-05-01

    Suspended-sediment and dissolved-solid (salt) loads decreased after the early 1940s in the Colorado Plateau portion of the Colorado River basin, although discharge of major rivers — the Colorado, Green and San Juan — did not change significantly. This decline followed a period of high sediment yield caused by arroyo cutting. Reduced sediment loads have previously been explained by a change in sediment sampling procedures or changes in climate, land-use and conservation practices. More recent work has revealed that both decreased sediment production and sediment storage in channels of tributary basins produced the decline of sediment and salt loads. Sediment production and sediment storage are important components of incised-channel evolution, which involves sequential channel deepening, widening and finally floodplain formation. Accordingly, the widespread arroyo incision of the late nineteenth century resulted initially in high sediment loads. Since then, loads have decreased as incised channels (arroyos) have stabilized and begun to aggrade. However, during the 1940s, a period of low peak discharges permitted vegetational colonization of the valley floors, which further reduced sediment loads and promoted channel stabilization. This explanation is supported by experimental studies and field observations. Both geomorphic and hydrologic factors contributed to sediment storage and decreased sediment and salt loads in the upper Colorado River basin.

  5. Influence of hydropower dams on the composition of the suspended and riverbank sediments in the Danube.

    PubMed

    Klaver, Gerard; van Os, Bertil; Negrel, Philippe; Petelet-Giraud, Emmanuelle

    2007-08-01

    Large hydropower dams have major impacts on flow regime, sediment transport and the characteristics of water and sediment in downstream rivers. The Gabcikovo and Iron Gate dams divide the studied Danube transect (rkm 1895-795) into three parts. In the Gabcikovo Reservoir (length of 40km) only a part of the incoming suspended sediments were deposited. Contrary to this, in the much larger Iron Gate backwater zone and reservoir (length of 310km) all riverine suspended sediments were deposited within the reservoir. Subsequently, suspended sediments were transported by tributaries into the Iron Gate backwater zone. Here they were modified by fractional sedimentation before they transgressed downstream via the dams. Compared with undammed Danube sections, Iron Gate reservoir sediment and suspended matter showed higher clay contents and different K/Ga and Metal/Ga ratios. These findings emphasize the importance of reservoir-river sediment-fractionation.

  6. Spatial Variability of Metals in Surface Water and Sediment in the Langat River and Geochemical Factors That Influence Their Water-Sediment Interactions

    PubMed Central

    Lim, Wan Ying; Aris, Ahmad Zaharin; Zakaria, Mohamad Pauzi

    2012-01-01

    This paper determines the controlling factors that influence the metals' behavior water-sediment interaction facies and distribution of elemental content (75As, 111Cd, 59Co, 52Cr, 60Ni, and 208Pb) in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals' concentration varied among stations. Metal concentrations of water ranged between 0.08–24.71 μg/L for As, <0.01–0.53 μg/L for Cd, 0.06–6.22 μg/L for Co, 0.32–4.67 μg/L for Cr, 0.80–24.72 μg/L for Ni, and <0.005–6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47–30.04 mg/kg for As, 0.02–0.18 mg/kg for Cd, 0.87–4.66 mg/kg for Co, 4.31–29.04 mg/kg for Cr, 2.33–8.25 mg/kg for Ni and 5.57–55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb) were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans. PMID:22919346

  7. Influence of forest road buffer zones on sediment transport in the Southern Appalachian Region

    Treesearch

    Johnny M. Grace; Stanley J. Zarnoch

    2013-01-01

    A gap exists in the understanding of the effectiveness of forest road best management practices (BMP) in controlling sediment movement and minimizing risks of sediment delivery to forest streams. The objective of this paper is to report the findings of investigations to assess sediment travel distances downslope of forest roads in the Appalachian region, relate...

  8. The influence of mariculture on mercury distribution in sediments and fish around Hong Kong and adjacent mainland China waters.

    PubMed

    Liang, Peng; Shao, Ding-Ding; Wu, Sheng-Chun; Shi, Jian-Bo; Sun, Xiao-lin; Wu, Fu-Yong; Lo, S C L; Wang, Wen-Xiong; Wong, Ming H

    2011-02-01

    To study the influence of mariculture on mercury (Hg) speciation and distribution in sediments and cultured fish around Hong Kong and adjacent mainland China waters, sediment samples were collected from six mariculture sites and the corresponding reference sites, 200-300 m away from the mariculture sites. Mariculture activities increased total mercury, organic matter, carbon, nitrogen and sulfur concentrations in the surface sediments underneath mariculture sites, possibly due to the accumulation of unconsumed fish feed and fish excretion. However, methylmercury (MeHg) concentrations and the ratio of MeHg to THg (% MeHg) in sediments underneath mariculture sites were lower than the corresponding reference sites. The % MeHg in sediments was negatively correlated (r = -0.579, p < 0.05) with organic matter (OM) content among all sites, indicating that OM may have inhibited Hg methylation in surface sediments. Three mariculture fish species were collected from each mariculture site, including red snapper (Lutjanus campechanus), orange-spotted grouper (Epinephelus coioides) and snubnose pompano (Trachinotus blochii). The average MeHg concentration in fish muscle was 75 μg kg⁻¹ (wet weight), and the dietary intake of MeHg through fish consumption for Hong Kong residents was 0.37 μg kg⁻¹ week⁻¹, which was lower than the corresponding WHO limits (500 μg kg⁻¹ and 1.6 μg kg⁻¹ week⁻¹).

  9. Port and Harbor Security

    SciTech Connect

    Saito, T; Guthmuller, H; DeWeert, M

    2004-12-15

    Port and Harbor Security is a daunting task to which optics and photonics offers significant solutions. We are pleased to report that the 2005 Defense and Security Symposium (DSS, Orlando, FL) will include reports on active and passive photonic systems operating from both airborne and subsurface platforms. In addition to imaging techniques, there are various photonic applications, such as total internal reflection fluorescence (TIRF), which can be used to ''sniff'' for traces of explosives or contaminants in marine. These non-imaging technologies are beyond the scope of this article, but will also be represented at DSS 2005. We encourage colleagues to join our technical group to help us to make our ports and harbors safer and more secure.

  10. [The influences of ultrafiltration and alcohol sedimentation on protective effects of Radix Astragali and Radix Hedyseri against rat's cerebral ischemia].

    PubMed

    Liu, Yong-qi; Wang, Zhi-wang; Wei, Shu-chang; Yan, Chun-lu; Wang, Rui-qiong; Li, Ying-dong

    2015-03-01

    To investigate the influences of ultrafiltration and alcohol sedimentation on protective effects of Radix Astragali and Radix Hedyseri against rat's cerebral ischemia. Using dexamethasone (im.) and ligating common carotid artery, the rat stasis model combined transient cerebral ischemia was established to evaluate the effects of the ultrafiltration and alcohol sedimentation through detecting antioxidant system and other indexes in brain tissue. The results showed that the 6 g/kg water extract(crude drug), ultrafiltration and alcohol sedimentation of Radix Astragali and Radix Hedyseri could upgrade adenosine-triphosphate (ATP), superoxide dismutase (SOD) and catalase (CAT), and degrade malondialdehyde(MDA) and water content of brain tissue in rat stasis model combined transient cerebral ischemia, the water extract and ultrafiltration of them could degrade lactic acid (LD) of brain tissue, and the effects of alcohol sedimentation of Radix Astragali and Radix Hedyseri become weaker than water extract of them. The water extract, ultrafiltration and alcohol sedimentation of Radix Astragali and Radix Hedyseri have some protective effects on cerebral ischemia in rats, the effective differences of the extract through the same extraction method are not remarkable, and alcohol precipitation method has obvious influences effect on Radix Astragali and Radix Hedyseri.

  11. Influence of bioturbation on sediment respiration in advection- and diffusion-dominated systems

    NASA Astrophysics Data System (ADS)

    Baranov, Viktor; Krause, Stefan; Lewandowski, Jörg

    2017-04-01

    Ecosystem engineers are organisms, whose impact on ecosystem functioning is large compared to their abundance and biomass. Classic examples of ecosystem engineers are burrowing organisms whose activity is affecting the sediment matrix and pore solutes in aquatic sediments; this is called bioturbation. Constant reworking of the sediment matrix and transport of solutes caused by activities of sediment-dwelling organisms are modifying habitats and resource availability. Despite that progress of studies on the interactions between the animal bioturbation and the sediment respiration was rather slow, mostly due to the existing methodological limitations. Conceptual framework, formulated by Mermelloid-Blondin and Rosenberg (2006) is suggesting that impact of bioturbation on the sediment biogeochemistry will be much larger in sediments with low hydraulic conductivities (diffusion-dominated) than in sediments with high hydraulic conductivities (advection-dominated). In order to test this hypothesis in application to the sediment respiration, we have used the resazurin-resorufin bioreactive tracer system, which allowed us to decouple respiration of the sediment of microbiota. Our work has shown that in diffusion-dominated sediments (organic rich lake sediments) bioturbator's (bloodworms, larvae of Diptera, Chironomidae) activity could increase sediment aerobic respiration by 300%. In addition to that, impact of the bioturbators on the diffusion-dominated sediments respiration is growing with increasing temperature. Total oxygen consumption (TOU) in such sediments is also increasing by about 50% in bioturbated sediments in comparison with uninhabited sediments. On the other hand, in advection-dominated sediments (sandy sediments from marine tidal flats, bioturbated by brittlestars) we have observed no increase in TOU, and only slight (25%) increase in aerobic respiration in the presence of bioturbators. It became evident that due to the high hydraulic conductivity of

  12. Reconstructing historical trends of Berre lagoon contamination from surface sediment datasets: influences of industrial regulations and anthropogenic silt inputs.

    PubMed

    Rigaud, S; Radakovitch, O; Nerini, D; Picon, P; Garnier, J M

    2011-09-01

    These last decades, the Berre lagoon (in southeastern France) has been deeply affected since the 1930s by strong inputs of contaminants associated with industrial development and since 1966 by huge inputs of freshwater and silts due to the installation of a hydroelectric power plant. Surveys of the surface sediment contamination have been sparsely performed since 1964 for management and research purposes. These surveys were performed by various laboratories that investigated different chemicals and sampling areas using different analysis protocols. Therefore, the available data are disconnected in time and space and differ in quality. In order to reconstruct coherent time series of sediment contamination from this heterogeneous datasets and to discuss the influences of industrial and hydroelectric discharges we used a statistical approach. This approach is based on Principal Component Analysis (PCA) and Fuzzy clustering analysis on data from one extensive survey realized on surface sediments in 1976. The PCA allowed identifying two geochemical indexes describing the main surface sediment geochemical characteristics. The fuzzy clustering analysis on these indexes allowed identifying sub-areas under the specific influence of industrial or hydroelectric discharges. This allowed us to reconstruct, for each sub-area, a coherent and interpretable long-term time series of sediment contamination from the available database. Reconstructed temporal trends allowed us to estimate: (i) the overall decrease of sediment contamination since the mid-1970 attributed to industrial discharge regulations enacted at this period and (ii) the dilution of the concentrations of sediment bound contaminants induced by the hydroelectric power plant and its associated particulate matter inputs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Economic development influences on sediment-bound nitrogen and phosphorus accumulation of lakes in China.

    PubMed

    Ni, Zhaokui; Wang, Shengrui

    2015-12-01

    China has been confronted with serious water quality deterioration concurrent with rapid socioeconomic progress during the past 40 years. Consequently, knowledge about economic growth and lake water quality dynamics is important to understand eutrophication processes. Objectives were to (i) reconstruct historical nutrient accumulation and the basin economic progress on burial flux (BF); (ii) determine forms and structures of nitrogen (N) and phosphorus (P) in sediment and water using six cores in three of the most severely eutrophic lake areas in China (i.e., Eastern Plain, Yunnan-Guizhou Plain, and Inner Mongolia-Xinjiang regions). Results suggest that BFs of total nitrogen (TN) continued to increase in sediment, whereas total phosphorus (TP) levels were consistent or only slightly increased, except in highly polluted lakes during the past decades. Similar results were observed for concentrations of nutrients in water (i.e., increased N/P). This historical distribution pattern was correlated to long-term fertilization practices of farmers in the watershed (N fertilization exceeds that of P) and was contingent upon pollution control policies (e.g., emphasized P whereas N was ignored). Vertical profiles of BFs indicated that lake nutrient accumulation included three stages in China. Nutrient accumulation started in the 1980s, accelerated from the 1990s, and then declined after 2000. Before the 1980s, nutrients were relatively low and stable, with nutrient inputs being controlled by natural processes. Thereafter, N- and P-bound sediments dramatically increased due to the increasing influence of anthropogenic processes. Nutrients were primarily derived from industries and domestic sewage. After 2000, BFs of nutrients were steady and even decreased, owing to implementation of watershed load reduction policies. The decreasing NaOH-extracted P (Fe/Al-P) and increasing organic phosphorus (OP) indicated that the source of exogenous pollution underwent a shift. Inputs of

  14. The influence of the abandoned Kalecik Hg mine on water and stream sediments (Karaburun, Izmir, Turkey).

    PubMed

    Gemici, Unsal; Oyman, Tolga

    2003-08-01

    This study covers the geochemical investigations on water and stream sediments to evaluate the influence from the abandoned Kalecik Hg mine. The groundwater samples (S5, S8, S9, WW10) are neutral, slightly alkaline waters which have pH values varying between 7.3 and 7.5. Electrical conductivity (EC) values of groundwaters for spring samples are low (250-300 microS/cm). However, groundwater obtained from a deep well has a higher EC value of 950 microS/cm. Hg concentrations of groundwater samples vary between 0.01 and 0.13 microg/l. Hg concentrations of other water samples taken from mining area from surface waters and adits are between 0.10 and 0.99 microg/l. Adit water (A4) collected at the mine has the highest Hg content of 0.99 microg/l and a pH of 4.4. Trace element concentrations of mine water samples show variable values. As is observed only in MW1 (310 microg/l). A4 was enriched in Cd, Co and Cr and exceed the Turkish drinking water standards (Türk Standartlari Enstitüsü, 1997). Cu concentrations vary between 6.0 and 150 microg/l and are below the Turkish water standards. Mn concentrations in mine waters are between 0.02 and 4.9 mg/l. Only for sample A4 Mn value (4.9 mg/l) exceeds the standard level. Ni was enriched for all of the mine water samples and exceeds the safe standard level (20 microg/l) for drinking water. Of the major ions SO(4) shows a notable increase in this group reaching 650 mg/l that exceeds the drinking water standards. Stream sediment samples have abnormally high values for especially Hg and As, Sb, Ni, Cr metals. With the exception of sample Ss6 of which Hg concentration is 92 mg/kg, all the other samples have Hg contents of higher than 100 mg/kg. Pollution index values are significantly high and vary between 69 and 82 for stream sediment samples.

  15. The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

    NASA Astrophysics Data System (ADS)

    Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

    2014-12-01

    Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

  16. The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

    USGS Publications Warehouse

    Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

    2014-01-01

    Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

  17. Bottom current influenced sedimentation in the Argentine Basin and on the Argentine Continental Margin reflected in high resolution seismic data

    NASA Astrophysics Data System (ADS)

    von Lom-Keil, H.; Schacht, R.; Spiess, V.

    2003-04-01

    Sediment deposition and distribution in the western Argentine Basin and along the Argentine continental margin is strongly influenced by deep water current activity, i.e. the Antarctic Bottom Water (AABW), spreading northward along the continental margin below 4000 m, the southward flowing North Atlantic Deep Water (NADW) between 1500 and 3500 m and the northward oriented Antarctic Intermediate Water (AAIW) between 700 and 1100 m. Furthermore the Argentine continental margin is characterised by numerous deep incisions and channels, supporting vertical gravity driven sediment transport. In January 2000 and February 2001 cruises with R/V Meteor in the western South Atlantic Ocean, performed as part of the former Bremen Special Research Project 261 (Cruise M46/3) and as an ODP pre-site survey (Cruise M49/2), provided high resolution seismic information on the internal structure of these complex sedimentary structures. The south west Argentine Basin is covered by the huge Zapiola sediment drift, which reaches a sediment thickness of up to 3 km and is draped by extended fields of sediment waves. High resolution seismic profiles across the western part of the drift deposits allow a closer inspection of the onset and growth of the sediment wave coverage, which starts at 400 ms below seafloor. The data also suggest a movement of the western drift crest to the south west during the growth of the drift. Drift deposits, showing evidence of strong bottom water activity, are also a widespread feature along the deeper Argentine continental margin, especially in vicinity of deeply incised channels. These deposits are often associated with topside or embedded sediment layers showing a wavy topography. Further upslope indications for bottom current erosion can be identified as well as downslope sediment transport forming thick slump deposits.

  18. Cliff-nesting seabirds influence production and sediment chemistry of lakes situated above their colony.

    PubMed

    Hargan, K E; Michelutti, N; Coleman, K; Grooms, C; Blais, J M; Kimpe, L E; Gilchrist, G; Mallory, M; Smol, J P

    2017-01-15

    Seabirds that congregate in large numbers during the breeding season concentrate marine-derived nutrients to their terrestrial nesting sites, and these nutrients disperse and enhance production in nearby terrestrial, freshwater and marine ecosystems. In the Canadian Arctic, large seabird colonies (>100,000 breeding pairs) nest on cliff faces that drain directly in the ocean, ultimately returning the nutrients back to the marine environment from which they were derived. However, strong winds blowing up cliff faces could transport nutrients up in elevation and onto surrounding terrestrial and aquatic environments. Here, we assess the degree to which seabird nutrients and metals have been delivered to coastal lakes near Hudson Strait (Nunavut, Canada) over the past century. Three lakes located at a higher elevation and increasing distance from a thick-billed murre (Uria lomvia) colony (~400,000 breeding pairs) were sampled for surface water chemistry. In addition, algal assemblages, nitrogen isotopes, and metal/metalloids were analyzed in four dated sediment cores. Elevated nutrients and major ions, as well as an enriched δ(15)N signature in the sediment cores, were measured in the lake <100m from the cliff, whilst no comparable changes were recorded in lakes >1km from the seabird colony. In contrast, similar oligotrophic and benthic diatom assemblages were identified in all three lakes, suggesting that diatoms were not influenced by enhanced nutrient inputs in this Arctic environment. Chemical tracers (e.g., total mercury) and algal assemblages in the lake near the colony suggest climate warming since ~1950 was the most likely driver of limnological changes, but this effect was muted in the more distant lakes. These pronounced changes in the seabird-impacted lake suggest that, with warming air temperatures and diminished lake ice cover, longer growing seasons may allow for aquatic organisms to more fully exploit the seabird nutrient subsidies.

  19. Influence of a dam on fine-sediment storage in a canyon river

    NASA Astrophysics Data System (ADS)

    Hazel, Joseph E.; Topping, David J.; Schmidt, John C.; Kaplinski, Matt

    2006-03-01

    Glen Canyon Dam has caused a fundamental change in the distribution of fine sediment storage in the 99-km reach of the Colorado River in Marble Canyon, Grand Canyon National Park, Arizona. The two major storage sites for fine sediment (i.e., sand and finer material) in this canyon river are lateral recirculation eddies and the main-channel bed. We use a combination of methods, including direct measurement of sediment storage change, measurements of sediment flux, and comparison of the grain size of sediment found in different storage sites relative to the supply and that in transport, in order to evaluate the change in both the volume and location of sediment storage. The analysis shows that the bed of the main channel was an important storage environment for fine sediment in the predam era. In years of large seasonal accumulation, approximately 50% of the fine sediment supplied to the reach from upstream sources was stored on the main-channel bed. In contrast, sediment budgets constructed for two short-duration, high experimental releases from Glen Canyon Dam indicate that approximately 90% of the sediment discharge from the reach during each release was derived from eddy storage, rather than from sandy deposits on the main-channel bed. These results indicate that the majority of the fine sediment in Marble Canyon is now stored in eddies, even though they occupy a small percentage (˜17%) of the total river area. Because of a 95% reduction in the supply of fine sediment to Marble Canyon, future high releases without significant input of tributary sediment will potentially erode sediment from long-term eddy storage, resulting in continued degradation in Marble Canyon.

  20. Influence of a dam on fine-sediment storage in a canyon river

    USGS Publications Warehouse

    Hazel, J.E.; Topping, D.J.; Schmidt, J.C.; Kaplinski, M.

    2006-01-01

    Glen Canyon Dam has caused a fundamental change in the distribution of fine sediment storage in the 99-km reach of the Colorado River in Marble Canyon, Grand Canyon National Park, Arizona. The two major storage sites for fine sediment (i.e., sand and finer material) in this canyon river are lateral recirculation eddies and the main-channel bed. We use a combination of methods, including direct measurement of sediment storage change, measurements of sediment flux, and comparison of the grain size of sediment found in different storage sites relative to the supply and that in transport, in order to evaluate the change in both the volume and location of sediment storage. The analysis shows that the bed of the main channel was an important storage environment for fine sediment in the predam era. In years of large seasonal accumulation, approximately 50% of the fine sediment supplied to the reach from upstream sources was stored on the main-channel bed. In contrast, sediment budgets constructed for two short-duration, high experimental releases from Glen Canyon Dam indicate that approximately 90% of the sediment discharge from the reach during each release was derived from eddy storage, rather than from sandy deposits on the main-channel bed. These results indicate that the majority of the fine sediment in Marble Canyon is now stored in eddies, even though they occupy a small percentage (???17%) of the total river area. Because of a 95% reduction in the supply of fine sediment to Marble Canyon, future high releases without significant input of tributary sediment will potentially erode sediment from long-term eddy storage, resulting in continued degradation in Marble Canyon. Copyright 2006 by the American Geophysical Union.

  1. Evaluation of Upland Disposal of Oakland Harbor, California, Sediment. Volume 2: Inner and Outer Harbor Sediments

    DTIC Science & Technology

    1993-08-01

    1989. "Rate and Effects of PCB Accumulation on Eisenia foetida ," Technical Report R89/339, Technology for Society Division (MT) of Netherlands...zone at the discharge point from the upland disposal site and/or further treatment may be required for those solu- ble contaminants. A mixing zone...regard to treatment of soluble contaminants. Establishment of vegetation either by natural succession or by planting would further reduce contaminant

  2. Modern sedimentary environments in Boston Harbor, Massachusetts

    USGS Publications Warehouse

    Knebel, H. J.; Rendigs, R. R.; Bothner, Michael H.

    1991-01-01

    Analyses of sidescan-sonar records supplemented by available bathymetric, sedimentary, subbottom, and bottom-current data reveal the distributions of the following three categories of sedimentary environments within the glaciated, topographically complex Boston Harbor estuary in Massachusetts. 1) Environments of erosion appear on the sonographs either as patterns with isolated strong reflections or as uniform patterns of strong reflectivity. These patterns define outcrops of bedrock or till and coarse lag deposits that are being scoured and winnowed by tidal- and wave-induced currents. Erosional areas are located primarily along mainland and insular shores, within large channels that have strong tidal currents, atop submerged ridges and knolls, and across much of the harbor entrance. 2) Environments of deposition are depicted on the sidescan-sonar records as smooth, featureless surfaces that have low to moderate reflectivity. Depositional environments are found predominantly over shallow subtidal flats and in broad bathymetric lows where tidal currents are weak. Sediments within depositional areas are organic-rich sandy and clayey silts that are accumulating at rates ranging from 0.01 to 0.11 g/cm 2 /yr or 4000 to 46,100 metric tons/yr. The cumulative mass of modern mud in harbor depocenters is 24.3 million metric tons. 3) Environments of sediment reworking constitute areas affected by a combination of erosional and depositional processes. They are characterized on the sonographs by mosaics of light and dark patches produced by relatively subtle and gradational changes in reflectivity. Reworked sediments have diverse grain sizes that overlap and are transitional between those of the other two sedimentary environments, and they are indicative of highly variable bottom currents.

  3. Factors influencing mercury in freshwater surface sediments of northeastern North America.

    PubMed

    Kamman, Neil C; Chalmers, Ann; Clair, Thomas A; Major, Andrew; Moore, Richard B; Norton, Stephen A; Shanley, James B

    2005-03-01

    We report on an inventory and analysis of sediment mercury (Hg) concentrations from 579 sites across northeastern North America. Sediment Hg concentrations ranged from the limit of detection ca. 0.01-3.7 microg g(-1) (dry weight, d.w.), and the average concentration was 0.19 microg g(-1) (d.w.) Sediment methylmercury concentrations ranged from 0.15 to 21 ng g(-1) (d.w.) and the mean concentration was 3.83 ng g(-1) (d.w.). Total Hg concentrations (HgT) were greatest in lakes > reservoirs > rivers, although the proportion of Hg as methylmercury showed an inverse pattern. Total Hg was weakly and positively correlated with the sediment organic matter and percent of watershed as forested land, and weakly and negatively correlated with sediment solids content, drainage area, and agricultural land. Sediment methylmercury concentrations were weakly and positively correlated to wetland area, and weakly and negatively correlated to drainage area. Methylmercury, expressed as a percentage of HgT was positively correlated to agricultural land area. For sites with co-located sediment and fish-tissue sampling results, there was no relationship between sediment Hg and fish-tissue Hg. Finally, our data indicate that at least 44% of waters across the region have sediment HgT concentrations in excess of Canadian and United States minimum sediment contaminant guidelines for the protection of aquatic biota.

  4. Factors influencing mercury in freshwater surface sediments of northeastern North America

    USGS Publications Warehouse

    Kamman, N.C.; Chalmers, A.; Clair, T.A.; Major, A.; Moore, R.B.; Norton, S.A.; Shanley, J.B.

    2005-01-01

    We report on an inventory and analysis of sediment mercury (Hg) concentrations from 579 sites across northeastern North America. Sediment Hg concentrations ranged from the limit of detection ca. 0.01-3.7 ??g g -1 (dry weight, d.w.), and the average concentration was 0.19 ??g g-1 (d.w.) Sediment methylmercury concentrations ranged from 0.15 to 21 ng g-1 (d.w.) and the mean concentration was 3.83 ng g -1 (d.w.). Total Hg concentrations (HgT) were greatest in lakes > reservoirs > rivers, although the proportion of Hg as methylmercury showed an inverse pattern. Total Hg was weakly and positively correlated with the sediment organic matter and percent of watershed as forested land, and weakly and negatively correlated with sediment solids content, drainage area, and agricultural land. Sediment methylmercury concentrations were weakly and positively correlated to wetland area, and weakly and negatively correlated to drainage area. Methylmercury, expressed as a percentage of HgT was positively correlated to agricultural land area. For sites with co-located sediment and fish-tissue sampling results, there was no relationship between sediment Hg and fish-tissue Hg. Finally, our data indicate that at least 44% of waters across the region have sediment HgT concentrations in excess of Canadian and United States minimum sediment contaminant guidelines for the protection of aquatic biota. ?? 2005 Springer Science+Business Media, Inc.

  5. The influence of Sarcocornia fruticosa on retention of PAHs in salt marsh sediments (Sado estuary, Portugal).

    PubMed

    Martins, Marta; Ferreira, Ana Maria; Vale, Carlos

    2008-04-01

    Depth concentration profiles of PAHs, organic carbon and dissolved oxygen in non-colonised sediments and sediments colonised by Sarcocornia fruticosa from Mitrena salt marsh (Sado, Portugal) were determined in November 2004 and April 2005. Belowground biomass and PAH levels in below and aboveground material were also determined. In both periods, colonised sediments were oxygenated until 15-cm, rich in organic carbon (max 4.4%) and presented much higher PAH concentrations (max. 7.1 microg g(-1)) than non-colonised sediments (max. 0.55 microg g(-1)). Rooting sediments contained the highest PAH concentrations. The five- and six-ring compounds accounted to 50-75% of the total PAHs in colonised sediments, while only to 30% in non-colonised sediments. The elevated concentrations of PAHs in colonised sediments may be attributed to the transfer of dissolved PAH compounds towards the roots as plant uptake water and subsequent sequestration onto organically rich particles. A phase-partitioning mechanism probably explains the higher retention of the heavier PAHs. In addition oxygenated conditions of the rooting sediments favour the degradation of the lighter PAHs and explain the elevated proportion of the heavier compounds. Below and aboveground materials presented lower PAH concentrations (0.18-0.38 microg g(-1)) than colonised sediments. Only 3- and 4-PAHs were quantified in aboveground material, reflecting either preferential translocation of lighter compounds from roots or atmospheric deposition.

  6. Influence of acid volatile sulfide and metal concentrations on metal bioavailability to marine invertebrates in contaminated sediments

    USGS Publications Warehouse

    Lee, B.-G.; Lee, J.-S.; Luoma, S.N.; Choi, H.J.; Koh, C.-H.

    2000-01-01

    An 18-day microcosm study was conducted to evaluate the influence of acid volatile sulfides (AVS) and metal additions on bioaccumulation from sediments of Cd, Ni, and Zn in two clams (Macoma balthica and Potamocorbula amurensis) and three marine polychaetes (Neanthes arenaceodentata, Heteromastus filiformis, and Spiophanes missionensis). Manipulation of AVS by oxidation of naturally anoxic sediments allowed use of metal concentrations typical of nature and evaluation of processes important to chronic metal exposure. A vertical sediment column similar to that often found in nature was used to facilitate realistic biological behavior. Results showed that AVS or porewater (PW) metals controlled bioaccumulation in only 2 of 15 metal-animal combinations. Bioaccumulation of all three metals by the bivalves was related significantly to metal concentrations extracted from sediments (SEM) but not to [SEM - AVS] or PW metals. SEM predominantly influenced bioaccumulation of Ni and Zn in N. arenaceodentata, but Cd bioaccumulation followed PW Cd concentrations. SEM controlled tissue concentrations of all three metals in H. filiformis and S. missionensis, with minor influences from metal-sulfide chemistry. Significant bioaccumulation occurred when SEM was only a small fraction of AVS in several treatments. Three factors appeared to contribute to the differences between these bioaccumulation results and the results from toxicity tests reported previously: differences in experimental design, dietary uptake, and biological attributes of the species, including mode and depth of feeding.An 18-day microcosm study was conducted to evaluate the influence of acid volatile sulfides (AVS) and metal additions on bioaccumulation from sediments of Cd, Ni, and Zn in two clams (Macoma balthica and Potamocorbula amurensis) and three marine polychaetes (Neanthes arenaceodentata, Heteromastus filiformis, and Spiophanes missionensis). Manipulation of AVS by oxidation of naturally anoxic sediments

  7. Effects of long-term dumping of harbor-dredged material on macrozoobenthos at four disposal sites along the Emilia-Romagna coast (Northern Adriatic Sea, Italy).

    PubMed

    Simonini, R; Ansaloni, I; Cavallini, F; Graziosi, F; Iotti, M; Massamba N'siala, G; Mauri, M; Montanari, G; Preti, M; Prevedelli, D

    2005-12-01

    Sediment from harbors of the Emilia-Romagna (Northern Adriatic Sea) were dredged and dumped in four disposal areas characterized by muddy bottoms. The long-term effects of the dumping on macrozoobenthic communities were investigated before and after 6 month, 8 month, 2 years and 4 years. The disposal of dredged material did not influence the granulometry and %TOC in the sediment, and no alterations in the structure of the macrobenthic communities were observed in the four areas. The lack of impact could be ascribed to the environmental characteristics and precautionary measures taken to minimize the effects of the dumping. It appears that: (1) the communities of the dumping areas are well adapted to unstable environments; (2) the sediments were disposed gradually and homogeneously over relatively large areas; Other factors that help to reduce the impact of sediment disposal are the low concentrations of contaminants in dredged materials and the similarity of sediment in the dredged and disposal areas. Off-shore discharge appears a sustainable strategy for the management of uncontaminated dredged sediments from the Northern Adriatic Sea harbors.

  8. Evaluating the potential effects of hurricanes on long-term sediment accumulation in two micro-tidal sub-estuaries: Barnegat Bay and Little Egg Harbor, New Jersey, U.S.A.

    USGS Publications Warehouse

    Marot, Marci E.; Smith, Christopher G.; Ellis, Alisha M.; Wheaton, Cathryn J.

    2016-06-23

    This report serves as an archive for sedimentological and radiochemical data derived from the surface sediments and box cores. Downloadable data are available as Excel spreadsheets, PDF files, and JPEG files, and include sediment core data plots and x-radiographs, as well as physical-properties, grain-size, alpha-spectroscopy, and gamma-spectroscopy data. Federal Geographic Data Committee metadata are available for analytical datasets in the data downloads page of this report.

  9. Influence of sediment composition on apparent toxicity in a solid-phase test using bioluminescent bacteria

    SciTech Connect

    Benton, M.J.; Malott, M.L. |; Knight, S.S.; Cooper, C.M.; Benson, W.H.

    1995-03-01

    Clean and spiked sediment formulations of various silt:sand and clay:sand ratios were tested for toxicity using a bioassay that utilizes bioluminescent bacteria. Measured toxicities of clean and copper sulfate-spiked sediments were negatively but nonlinearly related with percent silt and percent clay, but no significant relationship existed between measured toxicity and sediment composition for methyl parathion-spiked formulations. Results suggest that solid-phase sediment bioassays using bioluminescence bacteria may be useful for testing the toxicities of single contaminants in formulated artificial sediments of known particle-size composition, and for repeated samples collected from the same site. However, extreme caution must be taken when testing sediments of varying composition or which may be differentially contaminated or contain a suite of contaminants.

  10. Variability of Nitrous Oxide Fluxes From West Falmouth Harbor, Cape Cod, Massachusetts

    NASA Astrophysics Data System (ADS)

    Green, A. C.; Crusius, J.; Kroeger, K. D.; Pugh, E. R.; Baldwin, S. M.; Bratton, J. F.

    2008-12-01

    Eutrophic estuaries are potentially important but under-examined sources of the greenhouse gas, nitrous oxide (N2O), to the atmosphere, yet they are also heterogeneous, with potential for N2O discharge from both surface waters and intertidal sediments. In order to investigate the range and variability of N2O fluxes in a nitrogen-enriched estuary, measurements of N2O fluxes were made in West Falmouth Harbor, Massachusetts, during the summer of 2008. West Falmouth Harbor is impacted by increased nitrogen loading through fresh groundwater discharge from upland residential areas and a wastewater treatment plant located within the watershed. Fluxes from intertidal sediments were examined using flux chambers in 42 different sites. These fluxes were highly variable but reached values as high as 3700 μmol N2O/m2/d (average 75 μmol N2O/m2/d). The highest flux measured in West Falmouth Harbor was approximately three orders of magnitude higher than the average flux recently reported for soils, implying that the processes that drive the high fluxes are worthy of attention for understanding controls on fluxes from coastal regions. Results suggest that enhanced N2O fluxes in West Falmouth Harbor may be influenced by the discharge of nitrogen and nitrous oxide-enriched groundwater. N2O concentrations in groundwater ranged from 5-160 times the saturation of nitrous oxide, levels which could drive a flux through surficial sediments. Furthermore, of the sites where visible groundwater discharge was present and resulted in the formation of a pool of fresh groundwater under the flux chamber, 78% produced a significant N2O flux, while only 38% of sites with no visible groundwater discharge produced a detectable N2O flux. Water column N2O fluxes in this location were ~16 μmol N2O/m2/d, assuming a typical estuary gas transfer velocity of 5 cm/hr. Although the intertidal zone contained "hotspots" with very high fluxes, the total flux from the West Falmouth Harbor water column was

  11. The influence of turbulent bursting on sediment resuspension under unidirectional currents

    NASA Astrophysics Data System (ADS)

    Salim, Sarik; Pattiaratchi, Charitha; Tinoco, Rafael; Coco, Giovanni; Hetzel, Yasha; Wijeratne, Sarath; Jayaratne, Ravindra

    2017-07-01

    Laboratory experiments were conducted in an open channel flume with a flat sandy bed to examine the role of turbulence on sediment resuspension. An acoustic Doppler velocimeter (ADV) was used to measure the instantaneous three-dimensional velocity components and acoustic backscatter as a proxy to suspended sediment concentration. Estimates of sediment transport assume that there is a mean critical velocity that needs to be exceeded before sediment transport is initiated. This approach does not consider the turbulent flow field that may initiate sediment resuspension through event-based processes such as the bursting phenomenon. In this paper, laboratory measurements were used to examine the sediment resuspension processes below and above the mean critical velocity. The results within a range above and below the measured mean critical velocity suggested that (1) the contribution of turbulent bursting events remained identical in both experimental conditions, (2) ejection and sweep events contributed more to the total sediment flux than up-acceleration and down-deceleration events, and (3) wavelet transform revealed a correlation between the momentum and sediment flux in both test conditions. Such similarities in conditions above and below the measured mean critical velocity highlight the need to re-evaluate the accuracy of a single time-averaged mean critical velocity for the initiation of sediment entrainment.

  12. Depositional Influences on Porewater Arsenic in Sediments of a Mining-Contaminated Freshwater Lake

    SciTech Connect

    Toevs, G.; Morra, M.J.; Winowiecki, L.; Strawn, D.; Polizzotto, M.L.; Fendorf, S.

    2009-05-26

    Arsenic-containing minerals mobilized during mining activities and deposited to Lake Coeur d'Alene (CDA), Idaho sediments represent a potential source of soluble As to the overlying water. Our objective was to delineate the processes controlling porewater As concentrations within Lake CDA sediments. Sediment and porewater As concentrations were determined, and solid-phase As associations were probed using X-ray absorption near-edge structure (XANES) spectroscopy. Although maximum As in the sediment porewaters varied from 8.4 to 16.2 microM, As sorption on iron oxyhydroxides at the oxic sediment-water interface prevented flux to overlying water. Floods deposit sediment containing variable amounts of arsenopyrite (FeAsS), with majorfloods depositing large amounts of sediment that bury and preserve reduced minerals. Periods of lower deposition increase sediment residence times in the oxic zone, promoting oxidation of reduced minerals, SO4(2-) efflux, and formation of oxide precipitates. Depositional events bury oxides containing sorbed As, transitioning them into anoxic environments where they undergo dissolution, releasing As to the porewater. High Fe:S ratios limit the formation of arsenic sulfides in the anoxic zone. As a result of As sequestration at the sediment-water interface and its release upon burial, decreased concentrations of porewater As will not occur unless As-bearing erosional inputs are eliminated.

  13. A multi-component statistic analysis for the influence of sediment/soil composition on the sorption of a nonionic surfactant (Triton X-100) onto natural sediments/soils.

    PubMed

    Zhu, Lizhong; Yang, Kun; Lou, Baofeng; Yuan, Bihao

    2003-11-01

    The contents of soil/sediment organic carbon and clay minerals (i.e. montmorillonite, kaolinite, illite, gibbsite and 1.4 nm minerals) for 21 natural soil/sediment samples and the sorption of Triton X-100 on these samples were determined. A multi-component statistic analysis was employed to investigate the importance of soil/sediment organic matters and clay minerals on their sorption of Triton X-100. The sorption power of soil/sediment composition for Triton X-100 conforms to an order of montmorillonite>organic carbon>illite>1.4 nm minerals (vermiculite+chlorite+1.4 nm intergrade mineral)>kaolinite. The sorption of Triton X-100 on a montmorillonite, a kaolinite and a humic acid were also investigated and consistent with the result of multi-component statistic analysis. It is clear that the sorption of Triton X-100 on soils or sediments is the combined contribution of soil/sediment organic matters and clay minerals, which depended on both the contents of soil/sediment organic matters and the types and contents of clay minerals. The important influence of illite on the sorption of nonionic surfactants onto soils/sediments is suggested and demonstrated in this paper. Surfactants for aquifer remediation application may be more efficient for the contaminated soils/sediments that contain little clay minerals with 2:1 structure because of the less sorption of nonionic surfactants on these soils/sediments.

  14. Influence of chemical reactivities of lipids bound in different pools on their isotopic compositions during degradation in marine sediments

    NASA Astrophysics Data System (ADS)

    Sun, M.; Pan, H.; Culp, R.

    2013-05-01

    Lipid biomarkers and associated compound specific stable carbon isotope compositions have been widely applied to study biogeochemical cycling of organic matter in natural environments. This experimental study was specifically designed to examine the influence of chemical reactivities of lipid compounds bound in different pools on their isotopic composition during microbial degradation in marine sediments. 13C-labeled (labeling at different carbon positions of fatty acid chains) and unlabeled tripalmitins were spiked and incubated in natural oxic (top 1 cm) and anoxic (> 10 cm) marine sediments. In anoxic sediments, neither naturally-occurred fatty acids nor tripalmitin-derived 16:0 fatty acid were apparently degraded within two months and hence no significant variation in stable carbon isotopic composition of 16:0 fatty acid was observed. However, in oxic sediments, both naturally-occurred fatty acids and spiked tripalmitin-derived 16:0 fatty acid were degraded by 26% - 95% during incubation. For natural fatty acids such as 14:0, 16:1, 18:1, 20:5/20:4, and >C20:0, degradation rates varied according to the following order: polyunsaturated > monounsaturated > short chain saturated > long chain saturated fatty acids, which reflects variable reactivities of natural lipid compounds from different sources. Tripalmitin-derived 16:0 fatty acid degraded at an at least 2-3× faster rate compared to naturally-occurred 16:0 in sediments. Meanwhile, isotopic compositions of 16:0 fatty acid in the oxic sediments shifted negatively during incubation. It appears that the isotopic shifts are dependent on the amount of 13C-labeled compound spiked into the sediments but not related to the labeling position of 13C in the molecular structure. The results from this study provide direct evidence that the relative reactivities of lipid compounds from different sources (or different pools) can cause alterations in molecular isotopic composition during microbial degradation in natural

  15. Geochemistry of Cd, Cr, and Zn in highly contaminated sediments and its influences on assimilation by marine bivalves.

    PubMed

    Fan, Wenhong; Wang, Wen-Xiong; Chen, Jingsheng

    2002-12-01

    only relatively apparent for Cd. The influences of metal speciation on metal bioavailability can be confounded by the degree to which sediments are contaminated with metals.

  16. The Influence of Sediment Flux from Nanga Parbat in Interpreting Regional Erosion Patterns from the Indus Fan

    NASA Astrophysics Data System (ADS)

    Clift, P. D.; Lee, J. I.; Blusztajn, J.; Layne, G. D.; Blum, J. D.; Hildebrand, P.; Khan, A. A.

    2001-12-01

    The Indus is the only major river in the western Himalaya and its sedimentary flux into the Indus Fan might be expected to contain an erosional record of the growth of high topography since India-Asia collision. Interpretation of regional seismic profiles across the shelf and continental slope suggests sedimentation rates peaking in the Middle Miocene (11-16 Ma), then falling to the present day. This variability does not correlate with apparent monsoon intensification at 8.5 Ma or with Late Miocene to Recent exhumation in the Nanga Parbat-Haramosh Massif (NPHM). There is however a first order correlation between sedimentation and rapid exhumation of the Karakoram Batholith and start of motion on the Karakoram Fault. However, in order to understand the meaning of ancient periods of rapid sedimentation on the fan we must first understand the influence that very rapidly uplifting crystalline massifs have on the flux of sediment to the modern Indus River. The NPHM located in the western syntaxis of the Himalaya is one of the most rapidly exhuming massifs known globally and potentially major source of sediment. Comparison of the trace element chemistry of single amphibole grains from Indus River sands located up and downstream of NPHM demonstrates that erosion from this region is not a major contributor of these minerals to the river bedload. Although bulk sediment ɛ Nd falls in the Indus between the Indus Suture in Ladakh and the Arabian Sea because of mixing with India Plate sources, values downstream of NPHM suggests that this body contributes only 13% of the sediment reaching the foreland and 6-10% of that reaching the Arabian Sea. Consequently, Nd isotopic analysis confirms that the NPHM is a not a dominant sediment source to the Indus Fan. Single grain, ion microprobe Pb isotope analyses of K-feldspars from the Indus Fan and river confirm the Karakoram and suture zone arc batholiths as the dominant modern sediment sources, with much less flux from Indian Plate

  17. Grain size associations of branched tetraether lipids in soils and riverbank sediments: influence of hydrodynamic sorting processes

    NASA Astrophysics Data System (ADS)

    Peterse, Francien; Eglinton, Timothy I.

    2017-06-01

    We analyzed the abundance and distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in grain size fractions of 7 globally distributed river flank sediments and catchment soils in order to determine if and how the initial soil-brGDGT signature is influenced by hydrodynamic sorting upon entering a river and during subsequent transport from land to sea. BrGDGTs are hypothesized to form associations with high-surface-area fine-grained minerals in soils. Such associations, if maintained during transport, may impart resistance to degradation and promote downstream transport, reducing potential interferences by aquatic brGDGTs. We find that brGDGTs are indeed primarily associated with organic carbon (OC) bound to the clay-silt fraction (<63μm) in both soils and river sediments, and that these associations appear to be maintained during river transport. However, the relative distribution of individual brGDGTs among size fractions is relatively uniform, suggesting that brGDGTs are well mixed in river sediments and that OC-mineral associations are continuously renewed. Consequently, the brGDGT signature finally stored in continental margin sediments appears insensitive to differential particle transport processes. Nevertheless, the lower (upstream) temperature signal generally reflected by brGDGTs in river sediments may also be explained by a contribution of in situ produced brGDGTs leading to an underestimation of reconstructed air temperatures.

  18. Influence of food availability on the spatial distribution of juvenile fish within soft sediment nursery habitats

    NASA Astrophysics Data System (ADS)

    Tableau, A.; Brind'Amour, A.; Woillez, M.; Le Bris, H.

    2016-05-01

    Soft sediments in coastal shallow waters constitute nursery habitats for juveniles of several flatfishes. The quality of a nursery is defined by its capacity to optimize the growth and the survival of juvenile fish. The influence of biotic factors, such as food availability, is poorly studied at the scale of a nursery ground. Whether food availability limits juvenile survival is still uncertain. A spatial approach is used to understand the influence of food availability on the distribution of juvenile fish of various benthic and demersal species in the Bay of Vilaine (France), a productive nursery ground. We quantified the spatial overlap between benthic macro-invertebrates and their predators (juvenile fish) to assess if the latter were spatially covering the most productive areas of the Bay. Three scenarios describing the shapes of the predator-prey spatial relationship were tested to quantify the strength of the relationship and consequently the importance of food availability in determining fish distribution. Our results underline that both food availability and fish densities vary greatly over the nursery ground. When considering small organisational levels (e.g., a single fish species), the predator-prey spatial relationship was not clear, likely because of additional environmental effects not identified here; but at larger organisational level (the whole juvenile fish community), a strong overlap between the fish predators and their prey was identified. The evidence that fish concentrate in sectors with high food availability suggests that either food is the limiting factor in that nursery or/and fish display behavioural responses by optimising their energetic expenditures associated with foraging. Further investigations are needed to test the two hypotheses and to assess the impact of benthic and demersal juvenile fish in the food web of coastal nurseries.

  19. Geochemical influences on assimilation of sediment-bound metals in clams and mussels

    USGS Publications Warehouse

    Griscom, S.B.; Fisher, N.S.; Luoma, S.N.

    2000-01-01

    A series of experiments was performed to evaluate the extent to which Cd, Co, Ag, Se, Cr, and Zn bound to sediments with different geochemical properties could be assimilated by the mussel Mytilus edulis and the clam Macoma balthica. Oxidized and reduced radiolabeled sediments were fed to suspension-feeding animals, the depuration patterns of the individuals were followed by ??-spectrometry, and the assimilation efficiencies (AEs) of ingested metals were determined. AEs from geochemically diverse sediments typically varied less than 2-fold and ranged from 1% for Cr to 42% for Zn. Metals were assimilated from anoxic sediment by both animals; Ag, Cd, and Co AEs in M. balthica were 9-16%, 2-fold lower than from oxic sediment, but in M. edulis AEs were about two times greater from anoxic sediment for all metals but Ag. For oxic sediment, Cd and Co AEs in M. edulis decreased 3-4-fold with increased sediment exposure time to the metals with smaller but significant effects also noted for Zn and Se but not Ag. A less pronounced decrease in AE for M. balthica was evident only after 6 months exposure time. Sequential extractions of the oxidized sediments showed a transfer of metals into more resistant sediment components over time, but the rate did not correlate with a decrease in metal AEs. Comparing the two bivalves, TOC concentrations had an inconsistent effect on metal AEs. AEs of metals from bacteria-coated glass beads were slightly higher than from humic acid-coated beads, which were comparable with whole-sediment AEs. There was correspondence of AE with desorption of Ag, Cd, Co, and Se (but not Zn) from sediments into pH 5 seawater, measured to simulate the gut pH of these bivalves. The results imply that metals associated with sulfides and anoxic sediments are bioavailable, that the bioavailability of metals from sediments decreases over exposure time, that organic carbon content generally has a small effect on AEs, and that AEs of sediment-bound metals differ among

  20. Geochemical influences on assimilation of sediment-bound metals in clams and mussels

    SciTech Connect

    Griscom, S.B.; Fisher, N.S.; Luoma, S.N.

    2000-01-01

    A series of experiments was performed to evaluate the extent to which Cd, Co, Ag, Se, Cr, and Zn bound to sediments with different geochemical properties could be assimilated by the mussel Mytilus edulis and the clam Macoma balthica. Oxidized and reduced radiolabeled sediments were fed to suspension-feeding animals, the depuration patterns of the individuals were followed by {gamma}-spectrometry, and the assimilation efficiencies (AEs) of ingested metals were determined. AEs from geochemically diverse sediments typically varied less than 2-fold and ranged from 1% for Cr to 42% for Zn. Metals were assimilated from anoxic sediment by both animals; Ag, Cd, and Co AEs in M. balthica were 9--16%, 2-fold lower than from oxic sediment, but in M. edulis AEs were about two times greater from anoxic sediment for all metals but Ag. For oxic sediment, Cd and Co AEs in M. edulis decreased 3--4-fold with increased sediment exposure time to the metals with smaller but significant effects also noted for Zn and Se but not Ag. A less pronounced decrease in AE for M. balthica was evident only after 6 months exposure time. Sequential extractions of the oxidized sediments showed a transfer of metals into more resistant sediment components over time, but the rate did not correlate with a decrease in metal AEs. Comparing the two bivalves, TOC concentrations had an inconsistent effect on metal AEs. AEs of metals from bacteria-coated glass beads were slightly higher than from humic acid-coated beads, which were comparable with whole-sediment AEs. There was correspondence of AE with desorption of Ag, Cd, Co, and Se (but not Zn) from sediments into pH 5 seawater, measured to simulate the gut pH of these bivalves. The results imply that metals associated with sulfides and anoxic sediments are bioavailable, that the bioavailability of metals from sediments decreases over exposure time, that organic carbon content generally has a small effect on AEs, and that AEs of sediment-bound metals differ

  1. PAH content, toxicity and genotoxicity of coastal marine sediments from the Rovinj area, Northern Adriatic, Croatia.

    PubMed

    Bihari, Nevenka; Fafandel, Maja; Hamer, Bojan; Kralj-Bilen, Blanka

    2006-08-01

    Surface marine sediments collected from 8 sampling sites within the Rovinj coastal area, Northern Adriatic, Croatia, were used for determining priority pollutant polycyclic aromatic hydrocarbons (PAHs) and toxic/genotoxic potential of sediment organic extracts. Total PAH concentrations ranged from 32 microg/kg (protected area) to 13.2 mg/kg dry weight (harbor) and showed clear differences between pristine, urban industrial and harbor areas. PAHs distribution revealed their pyrogenic origin with some biogenic influence in harbor. At all sampling sites sediment extracts showed toxic potential that was consistent with the sediment type. No correlation between toxicity measured by Microtox assay and concentrations of individual or total PAHs was found. Noncytotoxic dose of sediment extracts showed no genotoxic potential in bacterial umu-test. DNA damage is positively related to total PAHs at 4 sampling sites (S-1, S-2, S-3, S-6), but the highest DNA damage was not observed at the site with the highest total sediment PAH content (S-5).

  2. Effects of Suspended Sediment on Early Life Stages of Smallmouth Bass (Micropterus dolomieu).

    PubMed

    Suedel, Burton C; Wilkens, Justin L; Kennedy, Alan J

    2017-01-01

    The resuspension of sediments caused by activities, such as dredging operations, is a concern in Great Lakes harbors where multiple fish species spawn. To address such concerns, smallmouth bass (Micropterus dolomieu) were exposed to uncontaminated suspended sediment (nominally 0, 100, 250, and 500 mg/L) continuously for 72 h to determine the effects on egg-hatching success and swim-up fry survival and growth. The test sediments were collected from two harbors: (1) fine-grained sediment in Grand Haven Harbor, Lake Michigan, and (2) coarser-grained sediment in Fairport Harbor, Lake Erie. Eggs exposed to total suspended solids (TSS) concentrations >100 mg/L resulted in decreased survival of post-hatch larval fish. Fry survival was >90 % at the highest exposure concentration (500 mg/L), but growth was decreased when the exposure concentration was >100 mg/L. Growth and survival of swim-up fry held for a 7- and 26-day post-exposure the grow-out period was variable suggesting that the sediment grain size and strain of fish may influence lingering effects after the cessation of exposure. The results suggest that exposed eggs hatched normally; however, newly hatched larvae, which are temporarily immobile, are more vulnerable to the effects of suspended sediment. The swim-up fry were found to be more sensitive to high TSS concentrations in sandy relative to silty sediment. These data represent a conservative exposure scenario that can be extrapolated to high-energy systems in the field to inform management decisions regarding the necessity for dredging windows or need to implement controls to protect M. dolomieu.

  3. Volatile organic compounds detected in vapor-diffusion samplers placed in sediments along and near the shoreline at Allen Harbor Landfill and Calf Pasture Point, Davisville, Rhode Island, March-April 1998

    USGS Publications Warehouse

    Lyford, F.P.; Kliever, J.D.; Scott, Clifford

    1999-01-01

    Volatile organic compounds are present in ground water at the Allen Harbor Landfill and the Calf Pasture Point sites on the former Naval Construction Battalion Center in Davisville, R.I. Vapor-diffusion samplers were used at the two sites during March-April 1998 to identify possible discharge points for contaminants along the shore of Allen Harbor and in two wetland areas near the shore. Results from vapor-diffusion samplers will be used in conjunction with other site information to evaluate proposed ground-water monitoring programs. Volatile organic compounds were detected in 41 of 115 samplers placed along the shoreline at the Allen Harbor Landfill. Trichloroethylene was the principal volatile organic compound detected of eight target compounds. The highest vapor concentration measured exceeded 300,000 parts per billion by volume in an area where TCE was detected in groundwater from nearby monitoring wells. Other chemicals detected in vapor-diffusion samplers included tetrachloroethylene, toluene, and benzene. Concentrations of individual volatile organic compounds were less than 100 parts per billion by volume in most samplers. Volatile organic compounds, principally trichloroethylene, were detected in 7 of 30 samplers placed along the shoreline at Calf Pasture Point; the highest trichloroethylene concentration was 1,900 parts per billion by volume. A trace concentration of tetrachloroethylene was detected in one of the samplers. One of 24 samplers placed in two wetland areas near the shore (suspected discharge areas for ground-water containing volatile organic compounds) detected trichloroethylene at a vapor concentration of 14 parts per billion by volume.

  4. Maintenance Operations of the Federal Navigation Channels and Structures at Bolles Harbor, Michigan.

    DTIC Science & Technology

    1978-02-01

    tanks , although the community will join the City of Monroe’s waste water treatment facilities at some future date. 2.02 Bolles Harbor is primarily a...septic tanks , were responsible for the classification of the harbor waters in 1965. A sewer tie-in with the Monroe Wastewater Treatment Plant is...some oil and grease. 2.16 Sediments. The bottom sediments were sampled and analyzed in 1969 by the Federal Water Pollution Control Administration (FWPCA

  5. Influence of water solubility, phase equilibria, and capillary pressure on methane occurrence in sediments

    SciTech Connect

    Claypool, G.E.

    1996-12-31

    Microbial methane is generated in rapidly accumulating marine sediments (>40 m/my) where pore waters are deficient in dissolved oxygen and sulfate. Based on indirect geochemical evidence, microbial methane generation is largely confined to depths of between 10 and 1000 meters beneath the sea floor. Under shelf conditions (water depth <200 m), methane concentrations can exceed solubility in pore water and accumulate as free gas, or escape the sediment as bubbles, or be oxidized in surface sediments. Under some deeper-water conditions of continental slope and rise sediments, more of the methane can be retained and buried because of increased solubility, and because methane in excess of solubility can be stabilized as methane hydrate. Few direct measurements of methane concentration in subsurface pore waters have been made. However, methane-water phase transitions (gas-water contacts, base of gas hydrate reflector) on seismic records can be used with methane solubility relationships to estimate gas contents of sediments. Comparison of various environments shows a relatively narrow range of dissolved methane contents. In marine sediments, free gas (and methane hydrate) is stable only in contact with methane-saturated pore water. Finer-grained sediments can be supersaturated with respect to a gas (and gas hydrate?) phase because of capillary pressure inhibition of bubble (or hydrate?) formation. The amount of methane dissolved in marine sediment pore water is necessarily larger than that present as gas hydrate.

  6. Influence of water solubility, phase equilibria, and capillary pressure on methane occurrence in sediments

    SciTech Connect

    Claypool, G.E. )

    1996-01-01

    Microbial methane is generated in rapidly accumulating marine sediments (>40 m/my) where pore waters are deficient in dissolved oxygen and sulfate. Based on indirect geochemical evidence, microbial methane generation is largely confined to depths of between 10 and 1000 meters beneath the sea floor. Under shelf conditions (water depth <200 m), methane concentrations can exceed solubility in pore water and accumulate as free gas, or escape the sediment as bubbles, or be oxidized in surface sediments. Under some deeper-water conditions of continental slope and rise sediments, more of the methane can be retained and buried because of increased solubility, and because methane in excess of solubility can be stabilized as methane hydrate. Few direct measurements of methane concentration in subsurface pore waters have been made. However, methane-water phase transitions (gas-water contacts, base of gas hydrate reflector) on seismic records can be used with methane solubility relationships to estimate gas contents of sediments. Comparison of various environments shows a relatively narrow range of dissolved methane contents. In marine sediments, free gas (and methane hydrate) is stable only in contact with methane-saturated pore water. Finer-grained sediments can be supersaturated with respect to a gas (and gas hydrate ) phase because of capillary pressure inhibition of bubble (or hydrate ) formation. The amount of methane dissolved in marine sediment pore water is necessarily larger than that present as gas hydrate.

  7. Influence of trophic status on PCB distribution in lake sediments and biota.

    PubMed

    Berglund, O; Larsson, P; Ewald, G; Okla, L

    2001-01-01

    We investigated the relationship between trophic status and polychlorinated biphenyl (PCB) distribution in 19 Swedish lakes. We analyzed PCB in water, phytoplankton, zooplankton, fish and sediment during two sampling periods, in spring and summer. The mass of sigma PCB in the lake sediments was positively related to lake trophy, i.e. more PCBs were accumulated and buried in the sediment of eutrophic lakes than in oligotrophic lakes. In the oligotrophic lakes a greater fraction of the total PCB load was dissolved in water. We conclude that this is a result of higher sedimentation rates in eutrophic lakes and relatively lower turnover of organic carbon in the water column of the shallow, eutrophic lakes. In the stratified lakes, the amount of PCB per cubic meter in the epilimnion decreased from spring to summer. We suggest that sedimentation of plankton beneath the thermocline during stratification act as a sink process of PCBs from the epilimnion.

  8. Mechanical properties of sediment determine burrowing success and influence distribution of two lugworm species.

    PubMed

    Crane, R L; Merz, R A

    2017-09-15

    We apply new perspectives on how organisms burrow by examining the association of in situ variation in sediment mechanical properties with burrowing ability and species distribution of two sympatric lugworms, Abarenicola pacifica and Abarenicola claparedi We quantified the sediment's resistance to penetration and its grain size distribution at sites inhabited by each species. Abarenicola pacifica individuals were found in significantly harder to penetrate, more heterogeneous sediments. We compared worm burrowing ability using reciprocal transplant experiments. Worms from firmer sediments, A. pacifica, were able to make successful steep burrows in sediments characteristic of either species. In contrast, A. claparedi individuals often failed to complete successful burrows in the firmer A. pacifica sediment. To examine how morphological differences could explain these patterns, we compared body wall musculature and measured how well individuals support their own bodies when draped over a cantilever. Lugworms from the firmer sediment had thicker body wall musculature and held their bodies more rigidly than did worms from softer sediments. Additionally, we observed subtle differences in the papillae on the proboscises' surfaces, which could affect worm-sediment interactions, but we found no differences in the chaetae of the two species. Abarenicola claparedi produced more mucus, which could be important in shoring up burrow walls in their shifting, sandy habitat. This study presents the first example of using field-based experiments to determine how sediment mechanical properties and worm burrowing ability could act to determine organismal distribution. Our findings have broader ecological implications because of the role of lugworms as ecosystem engineers. © 2017. Published by The Company of Biologists Ltd.

  9. Influence of Vegetation on Sediment Accumulation in Restored Tidal Saltmarshes: Field Evidence from the Blackwater Estuary, Essex, UK

    NASA Astrophysics Data System (ADS)

    Price, D.; French, J.; Burningham, H.

    2013-12-01

    -vegetated areas, even when other influences, such as elevation were removed. However, sediment retention at the vegetated sites was higher, at times double that in the bare areas. This implies that vegetation acts primarily to inhibit sediment resuspension by waves rather than by favouring deposition from tidal flows.

  10. Estuarine studies in upper Grays Harbor, Washington

    USGS Publications Warehouse

    Beverage, Joseph P.; Swecker, Milton N.

    1969-01-01

    Improved management of the water resources of Grays Harbor, Wash., requires more data on the water quality of the harbor and a better understanding of the influences of industrial and domestic wastes on the local fisheries resources. To provide a more comprehensive understanding of these influences, the U.S. Geological Survey joined other agencies in a cooperative study of Grays Harbor. This report summarizes the Survey's study of circulation patterns, description of water-quality conditions, and characterization of bottom material in the upper harbor. Salt water was found to intrude at least as far as Montesano, 28.4 nautical miles from the mouth of the harbor. Longitudinal salinity distributions were used to compute dispersion (diffusivity) coefficients ranging from 842 to 3,520 square feet per second. These values were corroborated by half-tidal-cycle dye studies. The waters of the harbor were found to be well mixed after extended periods of low fresh-water flow but stratified at high flows. Salinity data were used lo define the cumulative 'mean age' of the harbor water, which may be used to approximate a mean 'flushing time.' Velocity-time curves for the upper harbor are distorted from simple harmonic functions owing to channel geometry and frictional effects. Surface and bottom velocity data were used to estimate net tidal 'separation' distance, neglecting vertical mixing. Net separation distances between top and bottom water ranged from 1.65 nautical miles when fresh-water inflow was 610 cubic feet per second to 13.4 miles when inflow was 15,900 cubic feet per second. The cumulative mean age from integration of the fresh-water velocity equation was about twice that obtained from the salinity distribution. Excursion distances obtained with dye over half-tidal cycles exceeded those estimated from longitudinal salinity distributions and those obtained by earlier investigators who used floats. Net tidal excursions were as much as twice those obtained with floats

  11. Anaerobic oxidation of short-chain alkanes in hydrothermal sediments: potential influences on sulfur cycling and microbial diversity

    SciTech Connect

    Adams, MM; Hoarfrost, AL; Bose, A; Joye, SB; Girguis, PR

    2013-05-14

    Short-chain alkanes play a substantial role in carbon and sulfur cycling at hydrocarbon-rich environments globally, yet few studies have examined the metabolism of ethane (C-2), propane (C-3), and butane (C-4) in anoxic sediments in contrast to methane (C-1). In hydrothermal vent systems, short-chain alkanes are formed over relatively short geological time scales via thermogenic processes and often exist at high concentrations. The sediment-covered hydrothermal vent systems at Middle Valley (MV Juan de Fuca Ridge) are an ideal site for investigating the anaerobic oxidation of C-1-C-4 alkanes, given the elevated temperatures and dissolved hydrocarbon species characteristic of these metalliferous sediments. We examined whether MV microbial communities oxidized C-1-C-4 alkanes under mesophilic to thermophilic sulfate-reducing conditions. Here we present data from discrete temperature (25, 55, and 75 degrees C) anaerobic batch reactor incubations of MV sediments supplemented with individual alkanes. Co-registered alkane consumption and sulfate reduction (SR) measurements provide clear evidence for C-1-C-4 alkane oxidation linked to SR over time and across temperatures. In these anaerobic batch reactor sediments, 16S ribosomal RNA pyrosequencing revealed that Deltaproteobacteria, particularly a novel sulfate-reducing lineage, were the likely phylotypes mediating the oxidation of C-2-C-4 alkanes. Maximum C-1-C-4 alkane oxidation rates occurred at 55 degrees C, which reflects the mid-core sediment temperature profile and corroborates previous studies of rate maxima for the anaerobic oxidation of methane (AOM). Of the alkanes investigated, C-3 was oxidized at the highest rate over time, then C-4, C-2, and C-1, respectively. The implications of these results are discussed with respect to the potential competition between the anaerobic oxidation of C-2-C(4)alkanes with AOM for available oxidants and the influence on the fate of C-1 derived from these hydrothermal systems.

  12. Anaerobic oxidation of short-chain alkanes in hydrothermal sediments: potential influences on sulfur cycling and microbial diversity.

    PubMed

    Adams, Melissa M; Hoarfrost, Adrienne L; Bose, Arpita; Joye, Samantha B; Girguis, Peter R

    2013-01-01

    Short-chain alkanes play a substantial role in carbon and sulfur cycling at hydrocarbon-rich environments globally, yet few studies have examined the metabolism of ethane (C2), propane (C3), and butane (C4) in anoxic sediments in contrast to methane (C1). In hydrothermal vent systems, short-chain alkanes are formed over relatively short geological time scales via thermogenic processes and often exist at high concentrations. The sediment-covered hydrothermal vent systems at Middle Valley (MV, Juan de Fuca Ridge) are an ideal site for investigating the anaerobic oxidation of C1-C4 alkanes, given the elevated temperatures and dissolved hydrocarbon species characteristic of these metalliferous sediments. We examined whether MV microbial communities oxidized C1-C4 alkanes under mesophilic to thermophilic sulfate-reducing conditions. Here we present data from discrete temperature (25, 55, and 75°C) anaerobic batch reactor incubations of MV sediments supplemented with individual alkanes. Co-registered alkane consumption and sulfate reduction (SR) measurements provide clear evidence for C1-C4 alkane oxidation linked to SR over time and across temperatures. In these anaerobic batch reactor sediments, 16S ribosomal RNA pyrosequencing revealed that Deltaproteobacteria, particularly a novel sulfate-reducing lineage, were the likely phylotypes mediating the oxidation of C2-C4 alkanes. Maximum C1-C4 alkane oxidation rates occurred at 55°C, which reflects the mid-core sediment temperature profile and corroborates previous studies of rate maxima for the anaerobic oxidation of methane (AOM). Of the alkanes investigated, C3 was oxidized at the highest rate over time, then C4, C2, and C1, respectively. The implications of these results are discussed with respect to the potential competition between the anaerobic oxidation of C2-C4alkanes with AOM for available oxidants and the influence on the fate of C1 derived from these hydrothermal systems.