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Sample records for harbor sediment influence

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

    USGS Publications Warehouse

    Bothner, Michael H., (Edited By); 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

  2. HARBOR ISLAND REMEDIAL INVESTIGATION, MARINE SEDIMENT

    EPA Science Inventory

    The data set contains marine sediment data from a remedial investigation of Harbor Island, a National Priority List (NPL) Superfund site in Washington State. Both surface and subsurface marine sediments were collected. A station data set contain sampling station location and desc...

  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. Beryllium in sediments of Nagoya harbor estuaries

    SciTech Connect

    Itoh, K.

    1986-06-01

    Beryllium occurs naturally in minerals and oils. Other than the natural sources, considerable quantity of beryllium has been discharged from its smelting industry. Soil pollutants caused by beryllium in the circumference of its smelting industry on the banks of Nagoya harbor estuaries have been reported. Several methods for the spectroscopic determination of beryllium can not eliminate the interference caused by fluoride ion which remains in the digestion solution when hydrofluoric acid is used to degradate the silicate lattice. Accordingly, the authors attempted to improve the pretreatment in order to eliminate the effect of fluoride ion, and to make the procedure simpler and faster with high precision. A simple and sensitive method is presented for the determination of beryllium in sediments by atomic absorption spectroscopy using methylisobutylketone extraction with acetylacetone. They have carried out an extensive investigation on the pollution of sea water and sediments of Nagoya harbor estuaries, which is located in one of the most active industrial areas in Japan.

  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. 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.

  7. GEOCHEMICAL STUDY OF SEDIMENT CONTAMINATION IN NEW BEDFORD HARBOR, MASSACHUSETTS

    EPA Science Inventory

    Chemical analyses of sediment samples collected along a transect in New Bedford harbor revealed a gradient of increasing concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydro...

  8. 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...

  9. TOXICANT IDENTIFICATION STUDIES ON A HARBOR SEDIMENT

    EPA Science Inventory

    Presentation summarizes the results of experiments on sediment toxicity identification evaluation (TIE) techniques that allow researchers to characterize and identify chemical causes of acute toxicity in sediments that can be applied using the 10-d solid-phase sediment toxicity t...

  10. Comprehensive sediment quality of the NY/NJ harbor estuary

    SciTech Connect

    Adams, D.; O`Connor, J.

    1995-12-31

    The New York/New Jersey Harbor estuary is in the center of the most populated and industrialized area in the US. It provides habitat and sanctuary for many fish, shellfish, and birds, Years of accumulated and recent toxics contamination, primarily in sediments, has resulted in fishing bans, consumption advisories and controversy regarding disposal of dredge spoils. As part of a Management Plan for the Harbor, a strategy to manage the contaminated sediments was a necessity. Existing contaminant data for the Harbor was not sufficient to develop this strategy. The existing data had several shortcomings: biased collection locations precluded determination of areal estimates of contamination; conclusions regarding biological effects could not be made, because toxicity, chemistry and benthos usually were not determined concurrently, and large areas of the system lacked information. Additionally, datasets from the Harbor could not be aggregated, either due to incompatible gear or methods or lack of documentation as to procedures employed. To address these shortcomings, EPA Region 2, in partnership with the NY/NJ Harbor Estuary Program, NOAA and EMAP, designed a two-year program to characterize surficial sediment quality in the Harbor system. This program provides information on the extent and magnitude of sediment degradation throughout the system and within specific sub-basins. The characterization is based on the EMAP probability-based approach for describing ecological condition. Synoptic measurements of benthic macroinvertebrate assemblages, toxicity and chemistry were made at 168 stations in 6 sub-basins, along with water column profiles. Areal estimates of conditions were made for each sub-basin and for the Harbor as a whole. The authors will present an overview of the current status of surficial sediment contamination, toxicity and benthic macroinvertebrate conditions in the Harbor.

  11. 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. PMID:26849913

  12. 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.

  13. 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

  14. 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. PMID:12836979

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. ACUTE TOXICITY OF SEDIMENT FROM EAGLE HARBOR, WASHINGTON, TO THE INFAUNAL AMPHIPOD RHEPOXYNIUS ABRONIUS

    EPA Science Inventory

    Creosote-contaminated sediment from one station (EH08) in Eagle Harbor, Washington, is among the most toxic sediment yet tested from U.S. estuaries and coastal waters. he total concentration of 13 polynuclear aromatic hydrocarbons in EH08 sediment was 6,461 mg/kg (dry wt.). he cn...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

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

    USGS Publications Warehouse

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

    2000-01-01

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

  5. DEVELOPMENT OF BIOASSAY PROCEDURES FOR DEFINING POLLUTION OF HARBOR SEDIMENTS. PART I

    EPA Science Inventory

    This research investigates bioassay methods which may be useful in assessing the degree of pollution of harbor sediments. Procedures studied include 96 hr. toxicity tests employing Hexagenia limbata, Daphnia magna and Pontoporeia affinis as biological probes, monitoring cough fre...

  6. EXAMINATION OF DECHLORINATION PROCESSES AND PATHWAYS IN NEW BEDFORD HARBOR SEDIMENTS

    EPA Science Inventory

    Estuarine sediments from upper New Bedford Harbor, Massachusetts, which were heavily contaminated with polychlorinated biphenyls (PCBs), showed considerable compositional alterations of PCB residues relative to mixtures of Aroclor 1242 and 1254 standards, and PCB distributions pr...

  7. 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 frequent

  8. 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...

  9. 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

  10. Assessment of toxicity of polycyclic aromatic hydrocarbons in sediments of Kaohsiung Harbor, Taiwan.

    PubMed

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

    2013-10-01

    Polycyclic aromatic hydrocarbon (PAH) contamination and toxicity levels in the surface sediments of Kaohsiung Harbor, Taiwan were evaluated using sediment quality guidelines (SQGs) and toxic equivalent factors. Eighty surface sediment samples were collected from twenty locations in Kaohsiung Harbor for PAH analysis using gas chromatography/mass spectrometry (GC/MS). Concentrations of total PAHs varies from 34.0 to 16,700 ng/g with a mean concentration of 1490±2689 ng/g. The spatial distribution of PAHs reveals that PAH concentration is relatively higher in the river mouth regions, especially in the Salt River mouth where it gradually diminishes toward the harbor region. Distributions of PAHs, during both the wet and dry seasons, show that PAHs are more easily disbursed in the receiving sea water thereby leading to a wider range of chemical distribution. Hence, most of the chemicals accumulate in the harbor water channel. Diagnostic ratios show that the possible source of PAHs in the southern industrial area of the harbor could be coal combustion while in the other zones it could be petroleum combustion and/or a mixed sources. The toxic equivalent concentrations (TEQ(carc)) of PAHs varied from 3.9 to 1970 ng TEQ/g. The higher total TEQ(carc) values were found in the southern industrial area of the harbor. As compared with US sediment quality guidelines, the observed levels of PAHs in the industrial zone exceeded the effects range low (ERL), which will eventually cause acute biological damage. Based on the analyses using the SQGs, surface sediments from Kaohsiung Harbor were moderately contaminated and most samples have a low probability of toxicity pollution, except for the Salt River mouth situated in the south Kaohsiung Harbor area. This area has a medium to high probability of toxicity pollution. PMID:22818911

  11. 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.

  12. 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.

  13. PROPERTIES OF NEW YORK/NEW JERSEY HARBOR SEDIMENTS.

    SciTech Connect

    JONES, K.W.; FENG, H.; STERN, E.A.; NEUHAEUSLER, U.; OSAN, J.; MARINKOVIC, N.; SONG, Z.

    2005-05-20

    Sediments found in waterways around the world may contain toxic compounds of anthropogeilic origin that can harm the environment and human health. As a result, it is often necessary to remove them and find disposal methods that are environmentally and economically acceptable. Here, we report on results obtained in an experimental program to characterize the nature of the sediment contamination. The objective was to gain a better understanding of the properties of the sediments to develop better methods for understanding the fate and transport of the contaminants and for improving methods for their removal from the sediments. Our investigations made use of x-ray facilities at the Brookhaven National Synchrotron Light Source (NSLS) and the European Synchrotron Radiation Facility (ESRF) at Grenoble, France. The experiments included: measurements of the microstructure of the sediments using computed microtomography, x-ray absorption, and fluorescence microscopy with resolutions as low as 0.2 micrometers to obtain information on the relationships of organic and mineral components of the sediments and on the distribution of contaminants on the surfaces of the sediment grains, investigation of functional groups of chemical compounds using x-ray absorption near-edge spectroscopy (XANES) and Fourier Transform Infrared Spectroscopy (FTIR). Scanning electron microscopy (SEM) and electron probe measurements were made to ascertain the morphology of the sediment surfaces and the distribution of metals on individual sediment grains.

  14. 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.

  15. 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

    EPA Science Inventory

    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. eoplasia was observed in oysters after 30 and 60 days ...

  16. DECHLORINATIONS OF POLYCHLORINATED BIPHENYLS IN SEDIMENTS OF NEW BEDFORD HARBOR

    EPA Science Inventory

    The breakdown of polychlorinated biphenyl (PCB) congeners in situ in sediments heavily contaminated with PCBs by processes called reductive dechlorinations have been reported. hese studies characterized several distinct dechlorination patterns, caused by different strains of anae...

  17. Evaluation of factors affecting stakeholder risk perception of contaminated sediment disposal in Oslo harbor.

    PubMed

    Sparrevik, Magnus; Ellen, Gerald Jan; Duijn, Mike

    2011-01-01

    The management of environmental pollution has changed considerably since the growth of environmental awareness in the late 1960s. The general increased environmental concern and involvement of stakeholders in today's environmental issues may enhance the need to consider risk in a much broader social context rather than just as an estimate of ecological hazard. Risk perception and the constructs and images of risks held by stakeholders and society are important items to address in the management of environmental projects, including the management of contaminated sediments. Here we present a retrospective case study that evaluates factors affecting stakeholder risk perception of contaminated sediment disposal that occurred during a remediation project in Oslo harbor, Norway. The choice to dispose dredged contaminated sediments in a confined aquatic disposal (CAD) site rather than at a land disposal site has received a lot of societal attention, attracted large media coverage, and caused many public discussions. A mixed method approach is used to investigate how risk perceptive affective factors (PAF), socio-demographic aspects, and participatory aspects have influenced the various stakeholders' preferences for the two different disposal options. Risk perceptive factors such as transparency in the decision making process and controllability of the disposal options have been identified as important for risk perception. The results of the study also support the view that there is no sharp distinction in risk perception between experts and other parties and emphasizes the importance of addressing risk perceptive affective factors in similar environmental decision-making processes. Indeed, PAFs such as transparency, openness, and information are fundamental to address in sensitive environmental decisions, such as sediment disposal alternatives, in order to progress to more technical questions such as the controllability and safety. PMID:20809566

  18. 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.

  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. PMID:24682639

  20. 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

  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. Distribution and partitioning of polycyclic aromatic hydrocarbons (PAHs) in different size fractions in sediments from Boston Harbor, United States.

    PubMed

    Wang, X C; Zhang, Y X; Chen, R F

    2001-11-01

    The concentrations of 16 US EPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) were analyzed in four size fractions (< 62, 62-125, 125-250, and > 250 microm) in three contaminated Boston Harbor sediments. Total PAH concentrations ranged from 7.3 to 358 microg/g dry wt. and varied largely among the different size fractions in these sediments. For all three sites, the highest PAH concentrations were associated with the large size (> 250 microm) fractions while the fine silt and clay fractions (< 62 microm) contained relatively low PAHs. Despite the great concentration differences, the composition of PAHs in the four size fractions of these sediments showed similar patterns dominated by PAHs with three or more rings. By examining the distribution patterns of selected alkyl homologs to parent compounds, the results indicate that the major PAHs contributing to the high contamination in the inner harbor sediments were from pyrogenic sources. A positive correlation between PAHs and sedimentary organic carbon exists for all size fractions in the sediments. Calculated organic carbon normalized partition coefficients (log K(oc)) for selected major PAHs indicate near-equilibrium partitioning of PAHs among the different size fractions despite their large concentration variations. Sedimentary organic matter associated with different size fractions was the controlling factor for the observed distribution differences of PAHs among the size fractions. Our results also suggest that sedimentary organic matter with different origins and maturities may have somewhat different PAH sorption characteristics. Particulate organic matter of charcoal, plant detritus and Capitella fecal pellets in the sediments appear to sorb PAHs more strongly than organic matter associated with clay minerals. The strong association of PAHs with these organic particles in sediments will have a great influence not only on their distribution but also on long-term environmental impact. PMID:11763227

  3. Bacterial Communities in Polluted Seabed Sediments: A Molecular Biology Assay in Leghorn Harbor

    PubMed Central

    Verni, Franco; Petroni, Giulio

    2013-01-01

    Seabed sediments of commercial ports are often characterized by high pollution levels. Differences in number and distribution of bacteria in such areas can be related to distribution of pollutants in the port and to sediment conditions. In this study, the bacterial communities of five sites from Leghorn Harbor seabed were characterized, and the main bacterial groups were identified. T-RFLP was used for all samples; two 16S rRNA libraries and in silico digestion of clones were used to identify fingerprint profiles. Library data, phylogenetic analysis, and T-RFLP coupled with in silico digestion of the obtained sequences evidenced the dominance of Proteobacteria and the high percentage of Bacteroidetes in all sites. The approach highlighted similar bacterial communities between samples coming from the five sites, suggesting a modest differentiation among bacterial communities of different harbor seabed sediments and hence the capacity of bacterial communities to adapt to different levels and types of pollution. PMID:24227997

  4. Application of Toxicity Identification Evaluation (TIE) procedures for the characterization and management of dredged harbor sediments.

    PubMed

    Montero, N; Belzunce-Segarra, M J; Gonzalez, J-L; Menchaca, I; Garmendia, J M; Etxebarria, N; Nieto, O; Franco, J

    2013-06-15

    This study refers to the performance of Phase I Toxicity Identification Evaluation (TIE) procedures to identify the contaminants (i.e. organic compounds, metals and ammonia) exerting toxicity in marine sediments from the Pasaia harbor (Oiartzun estuary, northern Spain). The effectiveness of the manipulations to reduce toxicity was proved with the marine amphipod survival test (whole-sediment) and the sea urchin embryo-larval assay (elutriates). By means of TIEs it was concluded that organic compounds were the major contaminants exerting toxicity, although toxic effects by metals was also demonstrated. Additionally, the combination of Phase I treatments allowed to investigate the toxicity changes associated to the mobility of contaminants during dredging activities. Therefore, the performance of TIE procedures as another line of evidence in the decision-making process is recommended. They show a great potential to be implemented at different steps of the characterization and management of dredged harbor sediments. PMID:23465571

  5. Speciation of metals in contaminated sediments from Oskarshamn Harbor, Oskarshamn, Sweden.

    PubMed

    Fathollahzadeh, Homayoun; Kaczala, Fabio; Bhatnagar, Amit; Hogland, William

    2014-02-01

    Bottom sediments in coastal regions have been considered the ultimate sink for a number of contaminants, e.g., toxic metals. In this current study, speciation of metals in contaminated sediments of Oskarshamn harbor in the southeast of Sweden was performed in order to evaluate metal contents and their potential mobility and bioavailability. Sediment speciation was carried out by the sequential extraction BCR procedure for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and the exchangeable (F1), reducible (F2), oxidizable (F3), and residual (R) fractionswere determined. The results have shown that Zn and Cd were highly associated with the exchangeable fraction (F1) with 42–58 % and 43–46 %, respectively, of their total concentrations in the mobile phase. The assessment of sediment contamination on the basis of quality guidelines established by the Swedish Environmental Protection Agency (SEPA) and the Italian Ministry of Environment (Venice protocol for dredged sediments) has shown that sediments from Oskarshamn harbor are highly contaminated with toxic metals, especially Cu, Cd, Pb, Hg, As, and Zn posing potential ecological risks. Therefore, it is of crucial importance the implementation of adequate strategies to tackle contaminated sediments in coastal regions all over the world. PMID:24078237

  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. An integrated model for three-dimensional cohesive sediment transport in storm event and its application on Lianyungang Harbor, China

    NASA Astrophysics Data System (ADS)

    Yang, Xiaochen; Zhang, Qinghe; Zhang, Jinfeng; Tan, Feng; Wu, Yuru; Zhang, Na; Yang, Hua; Pang, Qixiu

    2015-03-01

    Prediction of cohesive sediment transport in storm process is important for both navigation safety and environment of the coastal zone. The difficulties to simulate cohesive sediment transport for a small-scale area such as around a harbor during storm events mainly include the low spatial resolution of the present reanalysis atmosphere forcing, the complex hydrodynamic and sediment transport processes, and their interactions. In this paper, an integrated atmosphere-wave-3D hydrodynamic and cohesive sediment transport model with unstructured grid, which is comprised of the Weather Research and Forecasting (WRF) model, Simulating WAves Nearshore (SWAN) model, and Finite-Volume Coastal Ocean Model (FVCOM), was developed to solve the abovementioned problems. For cohesive sediment, the flocculation and hindered settling were included, and a self-weight consolidation processes was introduced to the existing FVCOM. Interactions between components were considered by providing data fields to each other in an offline manner. The integrated model was applied to simulate cohesive sediment transport around Lianyungang Harbor, China, during Typhoon Wipha in 2007. Results identify that the atmosphere model WRF performed better in the simulation of wind field during typhoon process compared with QuikSCAT/National Centers for Environmental Prediction (QSCAT/NCEP) data. Simulation of wave model was directly affected by wind results as wave vector field driven by WRF wind field showed anticlockwise vortex while waves driven by QSCAT/NCEP wind field did not. The influence of water elevation and flow field on waves was great at the nearshore area. However, the effect of wave on current was not apparent, while the wind field played a more important role, especially on the current velocity. The cohesive sediment transport was greatly affected by wave due to the combined wave-current-induced shear stress. In general, simulation results of wind, wave, current, and sediment showed

  8. 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.

    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. 

  9. 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. PMID:23086130

  10. 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

  11. 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.

  12. 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)".

  13. Pacific lamprey (Entosphenus tridentatus) ammocoetes exposed to contaminated Portland Harbor sediments: Method development and effects on survival, growth, and behavior.

    PubMed

    Unrein, Julia R; Morris, Jeffrey M; Chitwood, Rob S; Lipton, Joshua; Peers, Jennifer; van de Wetering, Stan; Schreck, Carl B

    2016-08-01

    Many anthropogenic disturbances have contributed to the decline of Pacific lampreys (Entosphenus tridentatus), but potential negative effects of contaminants on lampreys are unclear. Lamprey ammocoetes are the only detritivorous fish in the lower Willamette River, Oregon, USA, and have been observed in Portland Harbor sediments. Their long benthic larval stage places them at risk from the effects of contaminated sediment. The authors developed experimental methods to assess the effects of contaminated sediment on the growth and behavior of field-collected ammocoetes reared in a laboratory. Specifically, they developed methods to assess individual growth and burrowing behavior. Burrowing performance demonstrated high variability among contaminated sediments; however, ammocoetes presented with noncontaminated reference sediment initiated burrowing more rapidly and completed it faster. Ammocoete reemergence from contaminated sediments suggests avoidance of some chemical compounds. The authors conducted long-term exposure experiments on individually held ammocoetes using sediment collected from their native Siletz River, which included the following: contaminated sediments collected from 9 sites within Portland Harbor, 2 uncontaminated reference sediments collected upstream, 1 uncontaminated sediment with characteristics similar to Portland Harbor sediments, and clean sand. They determined that a 24-h depuration period was sufficient to evaluate weight changes and observed no mortality or growth effects in fish exposed to any of the contaminated sediments. However, the effect on burrowing behavior appeared to be a sensitive endpoint, with potentially significant implications for predator avoidance. Environ Toxicol Chem 2016;35:2092-2102. © 2016 SETAC. PMID:26762215

  14. 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.

  15. 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. PMID:20554380

  16. 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.

  17. 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.

  18. Relation between PAH and black carbon contents in size fractions of Norwegian harbor sediments.

    PubMed

    Oen, Amy M P; Cornelissen, Gerard; Breedveld, Gijs D

    2006-05-01

    Distributions of total organic carbon (TOC), black carbon (BC), and polycyclic aromatic hydrocarbons (PAH) were investigated in different particle size fractions for four Norwegian harbor sediments. The total PAH (16-EPA) concentrations ranged from 2 to 113 mg/kg dry weight with the greatest fraction of PAH mass in the sand fraction for three of the four sediments. TOC contents ranged from 0.84% to 14.2% and BC contents from 0.085% to 1.7%. This corresponds to organic carbon (OC = TOC - BC) contents in the range of 0.81-14% and BC:TOC ratios of 1.3-18.1%. PAH isomer ratios suggested that the PAH in all four sediments were of pyrogenic origin. Furthermore, stronger correlations between PAH versus BC (r2 = 0.85) than versus OC (r2 = 0.15) were found. For all size fractions and bulk sediments, the PAH-to-BC ratios for the total PAHs were on average 6+/-3 mg PAH/g BC. These results suggest that PAH distributions were dominated by the presence of BC, rather than OC. As sorption to BC is much stronger than sorption to OC, this may result in significantly lower dissolved concentrations of PAH than expected on the basis of organic carbon partitioning alone. PMID:16249047

  19. 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. PMID:23062943

  20. Anthropogenic contamination of metals in sediments of the Santa Rosalía harbor, Baja California peninsula.

    PubMed

    Shumilin, Evgueni; Jiménez-Illescas, Ángel Rafael; López-López, Silverio

    2013-03-01

    To know the environment impact on a harbor of the Santa Rosalía port on the Baja California peninsula, the concentrations of metals (Cd, Co, Cu, Mn, Pb, U and Zn) in harbor sediments were determined for 13 stations and compared with their average upper Earth´s crust abundance. The mean enrichment factors, calculated using Al as a normalizer, were higher than the unity for Ag, Ba, Bi, Cd, Co, Cu, Mn, Ni, Pb, Sb, U, V and Zn. Concentrations of slightly enriched Cd in the sediments are below the effect range low (ERL) sediment quality guidelines value only at three stations. The levels of Pb in the harbor sediments at four stations (1, 6, 9 and 11) are between the ERL (46.7 mg kg(-1)) and the effect range medium (ERM) (218 mg kg(-1)), and Pb content in the rest of the sediment samples is higher than the ERM, demonstrating the high extent of the anthropogenic impact of this metal on the sedimentary environment. The total concentrations of the potentially toxic elements Cu (3,390 ± 804 mg kg(-1)) and Zn (1,916 ± 749 mg kg(-1)) very strongly exceed their ERM, showing a high possibility of toxicological danger for marine biota, living inside or entering the harbor. PMID:23277367

  1. 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. PMID:26515993

  2. 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.

  3. Bioremediation of contaminated harbor sediment: Development of a treatment assessment strategy

    SciTech Connect

    De Brabandere, J.; De Pauw, N.; Janssen, C.R.; Dumon, G.; Vanderhaegen, B.

    1995-12-31

    Different ex-situ microbial remediation techniques were assessed for the clean-up of contaminated sediments in the harbor of Zeebrugge (Belgium). Sediment contamination typically consisted of PAHs (5 to 1,200 ppm), TBT (up to 400 ppb) and mineral oils (400 to 8,000 ppm). In a first bench-scale phase, the remediation-efficiency of techniques based on stimulation of indigenous bacteria, a and/or 3 commercially available strains was evaluated using a combination of kinetic, {sup 14}C and respiration experiments, aimed at determining the degradation pathways and overall fate of the contaminants. At a pilot-scale 3 selected remediation techniques were assessed in four 40 M{sup 3}batch reactors (second phase). Aquatic toxicity tests were used to monitor bioremediation efficiency and the potential hazard of wastes and remediation by-products. The results from both phases of this study indicate that selected ex-situ microbial remediation techniques of contaminated sediments can remove 90% of both mineral oils and TBT, and between 70 to 90% of the total PAH concentration. Microbial, chemical and ecotoxicological aspects of this study will be discussed and details about the application of the developed assessment strategy in a full-scale treatment plant will be given.

  4. 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. PMID:21367431

  5. 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

  6. 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.

  7. PILOT-SCALE INCINERATION OF PCB-CONTAMINATED SEDIMENTS FROM THE HOT SPOT OF THE NEW BEDFORD HARBOR SUPERFUND SITE

    EPA Science Inventory

    Testing was performed at the EPA's Incineration Research Facility (IRF) to determine the incinerability of contaminated marine sediment from the Hot Spot in the New Bedford Harbor Superfund Site. he contaminants at this site were PCBs, at concentration up to >200,000 mg/kb, and m...

  8. PILOT-SCALE INCINERATION OF PCB-CONTAMINATED SEDIMENTS FROM THE NEW BEDFORD HARBOR HOT SPOT SUPERFUND SITE

    EPA Science Inventory

    Testing was performed at the EPA's Incineration Research Facility (IRF) to determine the incinerability of contaminated marine sediment from the Hot Spot in the New Bedford Harbor Superfund Site. he contaminants at this site were PCBs, at concentrations up to >200,000 mg/kg, and ...

  9. Recycling steel-manufacturing slag and harbor sediment into construction materials.

    PubMed

    Wei, Yu-Ling; Lin, Chang-Yuan; Cheng, Shao-Hsiang; Wang, H Paul

    2014-01-30

    Mixtures consisting of harbor sediment and slag waste from steel industry containing toxic components are fired to produce non-hazardous construction materials. The fired pellets become lighter as firing temperature increases. At a sintering temperature of ≦1050°C, the fired pellets are in a form of brick-like product, while at 1100°C, they become lightweight aggregates. Calcium silicate, kyanite, and cristobalite are newly formed in the pellets after firing, demonstrating that calcium oxide acts as a flux component and chemically reacted with Si- and/or Al-containing components to promote sintering. Dioxin/furan content present in the pure slag is 0.003ng I-TEQg(-1) and, for the fired pellet consisting of slag and sediment, the content appears to be destructed and diminishes to 0.0003ng I-TEQg(-1) after 950°C-firing; while it is 0.002ng I-TEQg(-1) after firing at 1100°C, suggesting that dioxins/furans in the 950°C-fired pellets have a greater chance to escape to atmosphere due to a slower sintering reaction and/or that construction of dioxins/furans from molten chloride salts co-exists with their destruction. Multiple toxicity characteristic leaching procedure extracts Cu, Cr, Zn, Se, Cd, Pb, Ba, As, and Hg from all fired products at negligible levels. PMID:24370934

  10. 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. PMID:25655751

  11. 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.

  12. 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.

  13. Predicting dredging-associated effects to coral reefs in Apra Harbor, Guam - Part 1: Sediment exposure modeling.

    PubMed

    Gailani, Joseph Z; Lackey, Tahirih C; King, David B; Bryant, Duncan; Kim, Sung-Chan; Shafer, Deborah J

    2016-03-01

    Model studies were conducted to investigate the potential coral reef sediment exposure from dredging associated with proposed development of a deepwater wharf in Apra Harbor, Guam. The Particle Tracking Model (PTM) was applied to quantify the exposure of coral reefs to material suspended by the dredging operations at two alternative sites. Key PTM features include the flexible capability of continuous multiple releases of sediment parcels, control of parcel/substrate interaction, and the ability to efficiently track vast numbers of parcels. This flexibility has facilitated simulating the combined effects of sediment released from clamshell dredging and chiseling within Apra Harbor. Because the rate of material released into the water column by some of the processes is not well understood or known a priori, the modeling approach was to bracket parameters within reasonable ranges to produce a suite of potential results from multiple model runs. Sensitivity analysis to model parameters is used to select the appropriate parameter values for bracketing. Data analysis results include mapping the time series and the maximum values of sedimentation, suspended sediment concentration, and deposition rate. Data were used to quantify various exposure processes that affect coral species in Apra Harbor. The goal of this research is to develop a robust methodology for quantifying and bracketing exposure mechanisms to coral (or other receptors) from dredging operations. These exposure values were utilized in an ecological assessment to predict effects (coral reef impacts) from various dredging scenarios. PMID:26692413

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

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

    PubMed Central

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

    2009-01-01

    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 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. PMID:19268364

  20. 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.

  1. 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.

  2. Anthropogenic accumulation of metals and metalloids in carbonate-rich sediments: Insights from the ancient harbor setting of Tyre (Lebanon)

    NASA Astrophysics Data System (ADS)

    Elmaleh, A.; Galy, A.; Allard, T.; Dairon, R.; Day, J. A.; Michel, F.; Marriner, N.; Morhange, C.; Couffignal, F.

    2012-04-01

    The Antique and Byzantine sediments of the northern harbor of Tyre (Lebanon) store high amounts of metals and metalloids as the result of a millennial anthropogenic contamination as well as of efficient trapping and immobilization processes. Geochemical and mineralogical analyses reveal the contrasted patterns for the accumulation of trace metal(loid)s in the sedimentary sequence recovered by coring the inner part, now emerged, of the ancient harbor. Lead, Sn, Cu and Ag concentrations can be as high as 3000, 150, 1000, and 1.2 μg/g, respectively. Enrichment factors were calculated with respect to (1) Th and (2) the chemistry of the substratum and appear to be driven by anthropogenic inputs. Indeed, a drastic change in both excess concentrations and concentration ratios is observed through Roman and Byzantine times, pointing to major intensification of the trade and use of metals in Tyre, coherent with historical data. Good preservation of the archeological signal, despite (1) sediment disturbances that have caused age depth inversions, and (2) the large time lapse since the time of deposition of anthropogenic trace metal(loid)s is probably due to the reducing character of the sediments. Tyre's sedimentary sequence provides an interesting analog for modern carbonate-rich harbor environments, in which a millenary accumulation of trace metal(loid)s has been overall well preserved and suggests a restricted mobility of anthropogenic contamination for a period of time in excess of 1500 years.

  3. 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.

  4. 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. PMID:20821674

  5. 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

  6. 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.

  7. 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. PMID:22572639

  8. [Distribution and bioavailability of seven heavy metals in mangrove wetland sediments in Dongzhai Harbor, Hainan Island, China].

    PubMed

    Ji, Yi-nuo; Zhao, Zhi-zhong; Wu, Dan; Fu, Xiao-nuo

    2016-02-01

    In this study, total and available contents of seven typical heavy metals (Cr, Ni, Cu, Zn, As, Cd and Pb) were determined in mangrove wetland sediments in Dongzhai Harbor, and the distribution characteristics and bioavailability of these heavy metals in sediment were analyzed. The results showed that all the metals contents in this area were higher than in mangrove wetlands in Yalong Bay and Sanya Bay, but lower than the average level in mangrove wetlands in South China and other areas in the world, which was at a moderate to low level. The contents of heavy metals in surface layer of sediment significantly differed among barren shoal, the edge and inside of forest. All the metals were obviously accompanyingly deposited in the columnar sediments, which indicated a strong homogeneous source. The available contents of seven heavy metals in the surface sediments were extracted by EDTA, which had the order of Cu>Cr>Zn>Ni>As>Pb>Cd. All the maximum ratios of available to total content of elements appeared in surface or -middle to upper layers, except Ni. There was significant positive correlation between available and total contents of target metals. PMID:27396135

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

    PubMed

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

    2011-06-01

    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 601ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145ng/g dw, compared with 13.1 and 23.8n/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. PMID:21529852

  10. 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.

  11. Spatial distribution and sources of polychlorinated biphenyls in surface sediments from the Zhoushan Archipelago and Xiangshan Harbor, East China Sea.

    PubMed

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

    2016-04-15

    This study investigated ambient concentrations and potential sources of polychlorinated biphenyls (PCBs) in surface sediments from the Zhoushan Archipelago and adjacent Xiangshan Harbor. The ∑18PCB (total 18 PCB) concentrations ranged between 1.48 and 7.94ng/g d.w., average at 4.20ng/g d.w., presenting a low adverse environmental risk. Penta-CB was the dominant congener, contributing 46.01%-86.44% of the total PCBs. Concentrations of PCBs were highest in the northeastern part of the Zhoushan Archipelago and Xiangshan Harbor. Principal component analysis (PCA) showed that PCBs have a mixed origin; atmospheric deposition and PCB dispersion from paint flakings being the main sources of PCB pollution. Aroclor 1245 and Clophen A50 were the potential PCB sources in all sampling sites. This paper provides the first intensive survey and statistical analyses of PCB distributions and sources in the Zhoushan Archipelago and adjacent Xiangshan Harbor. This study may provide a reference to environmental protection and monitoring of PCB pollution in the East China Sea. PMID:26892201

  12. USE OF CHEMICAL OXIDATION AND BIOREMEDIATION FOR TREATING INDIANA HARBOR CANAL SEDIMENT

    EPA Science Inventory

    The Indiana Harbor Canal is a man-made canal that connects Lake Michigan with the Calumet River. It is the recipient of extremely heavy hydrocarbon and steel slag contamination from oil refineries and steel mills dating back to the 19th century. The oil is heavily weathered and i...

  13. Option for treatment and disposal of contaminated sediments from New York/New Jersey Harbor. Final report

    SciTech Connect

    Averett, D.E.

    1994-01-01

    The U.S. Army Engineer District, New York, dredges several million cubic yards of sediment annually to maintain Federal navigation channels in New York and New Jersey Harbor. Most of this dredged material has characteristics that allow its disposal into open water or ocean sites. However, contaminant concentrations in some of the materials have led to this and other investigations of alternate management techniques for dredged material that is unacceptable for open-water disposal. These alternatives include ocean disposal with capping, coastal borrow pit disposal with capping, land-based or in-water confined disposal, and treatment of sediment to reduce the contaminant concentrations to levels acceptable for unrestricted disposal or beneficial uses. This report assesses available treatment and disposal altenatives for dioxin-contaminated dredged material from New York/New Jersey Harbor. Included in the assessment of treatment altenatives are a survey of available options, results from bench-scale tests of selected treatment technologies, development of the overall process train for promising treatment alternatives, an assessment of the feasibility of implementing the alternative, preliminary cost estimates, and a comparison of alternatives. Disposal alternatives are discussed on a similar basis and are compared with treatment altenatives.

  14. 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).

  15. Influence of sediment reduction on TCE degradation

    SciTech Connect

    Szecsody, James E.; Williams, Mark D.; Fruchter, Jonathan S.; Vermeul, Vincent R.; Evans, J. C.; Sklarew, Deborah S.

    2000-12-01

    A field-scale remediation technique for TCE and chromate is currently being implemented which uses a chemical treatment to reduce existing iron(III) in sediments. While reduction of some contaminants is well established, TCE data show that dechlorination is more complex, and the role of iron oxides to catalyze the reaction is not well understood. The purpose of this laboratory-scale study was to investigate the influence of temperature and partial sediment reduction on TCE dechlorination. Fully reduced sediments can degrade TCE at sufficiently fast rates (1.2 to 19 h) during static and transport experiments over 2oC to 25oC that a successful barrier could be made at the field scale. In contrast, partially reduced sediment resulted in up to a 3 order of magnitude decrease in the TCE dechlorination rate. While minimally reduced sediment had nearly no TCE reactivity, > 40% reduced sediment had considerably faster dechlorination rates. The second-order dependence of the TCE dechlorination rate on the fraction of reduced iron demonstrates the significant role of the iron oxide surface (as a catalyst or for surface coordination) for TCE dechlorination. Based on these results, the field-scale reduction was designed with specific reagent concen-trations, temperature, and flow rates to efficiently create a reductive barrier.

  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. 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.

  18. SUPPLEMENTAL RISK ANALYSIS FOR POTENTIAL AIR EMISSIONS FROM THE PROPOSED CONFINED DISPOSAL FACILITY FOR THE INDIANA HARBOR AND SHIPPING CANAL SEDIMENT DREDGING AND DISPOSAL PROJECT

    EPA Science Inventory

    In 1995, EPA completed a risk assessment for potential air emissions from the operation of a proposed confined disposal facility (CDF) to be constructed and operated by the U.S. Army Corps of Engineers for dredged sediments from the Indiana Harbor and Shipping Canal in East Chica...

  19. 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 ...

  20. 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. PMID:26121661

  1. Composition and variation of sediment bacterial and nirS-harboring bacterial communities at representative sites of the Bohai Gulf coastal zone, China.

    PubMed

    Guan, Xiangyu; Zhu, Lingling; Li, Youxun; Xie, Yuxuan; Zhao, Mingzhang; Luo, Ximing

    2014-04-01

    With rapid urbanization, anthropogenic activities are increasingly influencing the natural environment of the Bohai Bay. In this study, the composition and variation of bacterial and nirS-harboring bacterial communities in the coastal zone sediments of the Bohai Gulf were analyzed using PCR-based clone libraries. A total of 95 genera were detected in the bacterial communities, with Proteobacteria (72.1 %), Acidobacteria (10.5 %), Firmicutes (1.7 %), Bacteroidetes (1.4 %), Chloroflexi (0.7 %) and Planctomycetes (0.7 %) being the dominated phyla. The NirS sequences were divided into nine Clusters (A-I). Canonical correlation analysis showed that the bacterial or denitrifying communities were correlated with different environmental factors, such as total organic carbon, total nitrogen, ammonium, sulfate, etc. Furthermore, bacterial communities' composition and diversity are influenced by oil exploration, sewage discharge and other anthropogenic activities in the coastal area of the Bohai Sea. Thus, this study provided useful information on further research on regional or global environmental control and restore. PMID:24214680

  2. 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.

  3. 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.

  4. 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

  5. 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. PMID:12463548

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

    PubMed

    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 [Formula: see text]-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

  7. 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...

  8. 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.

  9. 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.

  10. 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

  11. 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. PMID:26802266

  12. 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. PMID:21671651

  13. 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

  14. Climate change influence on catchment sediment yield

    NASA Astrophysics Data System (ADS)

    Rulli, Maria Cristina; Grossi, Giovanna

    2010-05-01

    The effects of a change in climate are expected to be recognizable in many environmental aspects even at small spatial scales: atmospheric carbon dioxide concentration, air temperature, precipitation pattern (days of snowfall translate in days of rainfall), rainfall intensity and erosivity. As a consequence, strong modifications may affect the rate of evapo-transpiration, infiltration and plant biomass production, but also of the soil erosion. To which extent climate change may affect runoff production, soil erosion and sediment transport in upland catchments is investigated here by combining data of long term precipitation, sediment yield and future climate change provided by Global Circulation Models (GCMs) with a spatially distributed modeling approach to flow generation and surface erosion. The model accounts for changes in the structure and properties of soil and vegetation cover by combining the tube-flux approach to the topographic watershed partitioning through a parsimonious parametrization of the main hydrological processes. This model is used to predict hydrological and sediment fluxes for three small catchments in Saint Gabriel mountains of Southern California under control and climate change conditions. Simulation runs using a 45 years long record of hourly precipitation, both observed and referred to a future scenario, show that climate change may induce a significant modification in the catchment response to storms, with major effects on erosion and flood flows.

  15. Influence of meteorological parameters on particulates and atmospheric pollutants at Taichung harbor sampling site.

    PubMed

    Fang, Guor-Cheng; Wu, Yuh-Shen; Wen, Chih-Chung; Lee, Wen-Jhy; Chang, Shih-Yu

    2007-05-01

    Atmospheric aerosol particles and metallic concentrations, ionic species were monitored at the Experimental harbor of Taichung sampling site in this study. This work attempted to characterize metallic elements and ionic species associated with meteorological conditions variation on atmospheric particulate matter in TSP, PM2.5, PM2.5-10. The concentration distribution trend between TSP, PM2.5, PM2.5-10 particle concentration at the TH (Taichung harbor) sampling site were also displayed in this study. Besides, the meteorological conditions variation of metallic elements (Fe, Mg, Cr, Cu, Zn, Mn and Pb) and ions species (Cl(-), NO3 (-), SO4 (2-), NH4+, Mg2+, Ca2+ and Na+) concentrations attached with those particulate were also analyzed in this study. On non-parametric (Spearman) correlation analysis, the results indicated that the meteorological conditions have high correlation at largest particulate concentrations for TSP at TH sampling site in this study. In addition, the temperature and relative humidity of meteorological conditions that played a key role to affect particulate matter (PM) and have higher correlations then other meteorological conditions such as wind speed and atmospheric pressure. The parameter temperature and relative humidity also have high correlations with atmospheric pollutants compared with those of the other meteorological variables (wind speed, atmospheric pressure and prevalent wind direction). In addition, relative statistical equations between pollutants and meteorological variables were also characterized in this study. PMID:17057996

  16. 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).

  17. 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.

  18. New Bedford Harbor Superfund Project, Acushnet River Estuary engineering feasibility study of dredging and dredged-material disposal alternatives. Report 3. Characterization and elutriate testing of Acushnet River Estuary sediment. Technical report, August 1985-March 1988

    SciTech Connect

    Averett, D.E.

    1989-03-01

    Several of the alternatives being considered for the New Bedford Harbor Superfund Project involve dredging of contaminated sediment from the Acushnet River Estuary and placement of the contaminated dredged material in confined disposal areas. Evaluation of these alternatives requires testing sediment from the site to determine chemical and physical characteristics, settling properties, contaminant releases for various migration pathways, and treatment requirements for disposal area effluent. The purpose of this report is to describe the estuary composite sediment sample and the hot-spot-sediment sample tested at the US Army Engineer Waterways Experiment Station as part of the US Army Corps of Engineers' Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Bulk sediment chemistry, physical characteristics, and elutriate testing for the sediments are included.

  19. 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.

  20. 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

  1. 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

  2. Influence of sediment deposition on deep lithospheric tectonics

    NASA Astrophysics Data System (ADS)

    Gray, R.; Pysklywec, R. N.

    2012-06-01

    Previous geodynamic models of continental collision show that the behavior of the lithosphere can be strongly influenced by the presence of surface erosion. That said, absent from these investigations are the effects of sediment deposition. We quantitatively investigate this process using thermal-mechanical numerical experiments of the coupled processes of tectonic deformation and crustal mass flux. The models demonstrate that the inclusion of the effects of sediment deposition can change the style of deformation of the crust and consequently, the evolution of the underlying deforming mantle lithosphere. In the absence of sediment deposition, the early stages of collision are accommodated by subduction of lower crust and mantle lithosphere along a discrete shear zone beneath the overriding plate. Following this initial stage of subduction, the subducting lower crust and mantle lithosphere retreat from the collision zone, permitting the sub-lithospheric mantle to upwell and come into contact with the thickened upper crust. When sediment deposition is imposed subduction-like consumption of the subducting plate remains stable. The presence of sediment deposition introduces a negative Vy-component in the overriding plate in the area adjacent to the collisional zone. The negative Vy-component leads to a greater degree of coupling between the colliding continental plates and decoupling of the overriding upper crust and lower crust/mantle lithosphere. The results demonstrate the first quantitative insights into the feedback between surface deposition and tectonics.

  3. 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

  4. 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

  5. Influence of fibrinogen and haematocrit on erythrocyte sedimentation kinetics.

    PubMed

    Holley, L; Woodland, N; Hung, W T; Cordatos, K; Reuben, A

    1999-01-01

    This study investigates the influence of haematocrit, fibrinogen concentration and fibrinogen availability (amount of fibrinogen per red blood cell) on erythrocyte sedimentation. The Westergren technique was applied to blood samples from 36 subjects and to their blood manipulated to haematocrits of 10, 20, 30 and 40%. Readings were taken every 10 minutes for 300 minutes. Previous studies indicate that erythrocyte sedimentation occurs in three phases. In this study, we show that haematocrit has little influence on either the rate of fall of particles in the first phase (m1) or the duration of the first phase. This is also true for fibrinogen availability and for fibrinogen concentration at low haematocrits. At high haematocrits m1 increases with fibrinogen concentration. The rate of fall of rouleaux during phase 2 (m2) and ESR60 both decrease exponentially with haematocrit and increase linearly with fibrinogen concentration. While m2 is more closely correlated to fibrinogen availability than to fibrinogen concentration or to haematocrit, this is not the case for ESR60. Thus haematocrit, fibrinogen concentration and fibrinogen availability are more important to the velocity of sedimentation in the second phase than to the sedimenting velocity during phase 1 or to the duration of phase 1. PMID:10690265

  6. 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

  7. 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).

  8. Sediment Budgeting in Dam-Affected Rivers: Assessing the Influence of Damming, Tributaries, and Alluvial Valley Sediment Storage on Sediment Regimes

    NASA Astrophysics Data System (ADS)

    Wilcox, A. C.; Dekker, F. J.; Riebe, C. S.

    2014-12-01

    Although sediment supply is recognized as a fundamental driver of fluvial processes, measuring how dams affect sediment regimes and incorporating such knowledge into management strategies remains challenging. To determine the influences of damming, tributary supply, and valley morphology and sediment storage on downstream sediment supply in a dryland river, the Bill Williams River (BWR) in western Arizona, we measured basin erosion rates using cosmogenic nuclide analysis of beryllium-10 (10Be) at sites upstream and downstream of a dam along the BWR, as well as from tributaries downstream of the dam. Riverbed sediment mixing calculations were used to test if the dam, which blocks sediment supply from the upper 85% of the basin's drainage area, increases the proportion of tributary sediment to residual upstream sediment in mainstem samples downstream of the dam. Erosion rates in the BWR watershed are more than twice as large in the upper catchment (136 t km-2 yr-1) than in tributaries downstream of Alamo Dam (61 t km-2 yr-1). Tributaries downstream of the dam have little influence on mainstem sediment dynamics. The effect of the dam on reducing sediment supply is limited, however, because of the presence of large alluvial valleys along the mainstem BWR downstream of the dam that store substantial sediment and mitigate supply reductions from the upper watershed. These inferences, from our 10Be derived erosion rates and mixing calculations, are consistent with field observations of downstream changes in bed material size, which suggest that sediment-deficit conditions are restricted to a 10 km reach downstream of the dam, and limited reservoir bathymetry data. Many studies have suggested that tributary sediment inputs downstream of dams play a key role in mitigating dam-induced sediment deficits, but here we show that in a dryland river with ephemeral tributaries, sediment stored in alluvial valleys can also play a key role and in some cases trumps the role of

  9. 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.

  10. Influence of suspended inorganic sediment on airborne laser fluorosensor measurements

    NASA Technical Reports Server (NTRS)

    Poole, L. R.; Esaias, W. E.

    1983-01-01

    The results of Poole and Esaias (1982) are presently extended to an examination of the influence of inorganic sediment on the water Raman normalization procedure, as well as an assessment of the potential for using the Raman signal to monitor surface water attenuation properties. An optically perfect lidar system is assumed which has geometric properties representative of the Airborne Oceanographic Lidar, and is mounted on an airborne platform flying at an altitude of 150 m above the water surface. The results obtained suggest that caution should be exercised in attempts to quantitatively monitor changes in optical attenuation by means of remote measurements of the Raman scattering signal.

  11. [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, and with a…

  12. 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. PMID:26901731

  13. 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...

  14. 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

  15. 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

  16. 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. PMID:21195448

  17. 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...

  18. 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

  19. 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.

    2016-01-01

    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.

  20. 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.

  1. 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. PMID:25259499

  2. 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...

  3. 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.

  4. Seepage from channeled flows as influenced by PAM and sediment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seepage from water streams into unlined channels determines the proportion of water distributed to adjacent soil for plant use or soil or groundwater recharge, or conveyed to downstream reaches. We conducted a laboratory study to determine how sediment type (none, clay, silt), sediment concentratio...

  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., Jr.

    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. 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.

  7. CONTAMINANT TRANSPORT IN SEDIMENT UNDER THE INFLUENCE OF ADVECTIVE FLUX

    EPA Science Inventory

    Chemical flux across the sediment/water interface is controlled by a combination of diffusive, dispersive and advective processes. The advective process is a function of submarine groundwater discharge and tidal effects. In areas where surface water interacts with groundwater, ...

  8. 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...

  9. Influence of the submersed plant, Potamogeton perfoliatus, on nitrogen cycling in estuarine sediments

    USGS Publications Warehouse

    Caffrey, J.M.; Kemp, W.M.

    1993-01-01

    Using 15N isotope techniques P. perfoliatus is shown to have a significant influence on sediment N cycling by direct uptake of NH4+ and NO3- and by indirect mechanisms leading to enhanced nitrification and denitrification. -from Authors

  10. PHYSICAL AND CHEMICAL PARAMETERS OF SEDIMENT EXTRACTION AND FRACTIONATION THAT INFLUENCE TOXICITY AS EVALUATED BY MICROTOX

    EPA Science Inventory

    Several physical and chemical parameters of sediment extraction and fractionation of organic compounds that influence bioassay results were evaluated. ach parameter was evaluated with a photoluminescent bacterial bioassay (Microtox) as an end point. hree solvents (acetonitrile, a...

  11. Influence of small river derived sediment on the Northeastern South China Sea sedimentation processes in the last 40 K years

    NASA Astrophysics Data System (ADS)

    Cheng, Wan-Yen; Lin, Saulwood; Lou, Jiann-Yuh; Wei, Kuo-Yen; Liu, CharShine; Chen, Shing-Li; Wang, Yun-Shuen

    2015-04-01

    Small rivers derived particles are major source of sediment to the ocean in the present time. Small rivers in Taiwan are subjected to fast tectonic activity, high precipitation rate and erosion rate. The combined annual river particle load from small rivers on the Island of Taiwan is higher than that of the Mississippi River. A large fraction of those rivers particle may finding its way into the surrounding seas and ocean, e.g. South China Sea, East China Sea, and the Philippine Sea. Furthermore, due to the nature of particle transportation off rivers from Taiwan were connected by a number of canyon systems close by the river mouth, majority of those river particles were facilitated in delivering and deposited later further into the South China Sea deep basin. The objectives of this study are to understand spatial variations in sedimentation rates and to resolve the temporal differences in sedimentation in the Northeastern South China Sea region, and to evaluate influence of small river particles to the marginal sea. A set of cores was collected in overlying water depth within 1600 - 3300 m for mutilsensor core logging of magnetic susceptibility, density, and porosity. Foraminifera (G. sacculifer, G. conglobatus, O. universa) were picked and AMS C14 analyses for age determination. Grain size, organic carbon, carbonate and biogenic silica content were measured. The results show that large sedimentation rates difference existed in the study area. Earlier studies on sedimentation rate in the region west of our study area were in range of about 10 cm/kyr while our rates are about 20-40 cm/kyr and much higher near Taiwan. Bulk sedimentation rate were higher during the transition period between LGM and Holocene and lower during Holocene. Our results demonstrated that large quantity of particles from small rivers in Taiwan are and were major source of particle and are the dominating factor in controlling sediment deposition in the northeastern South China Sea.

  12. 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.

  13. 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

    2016-01-01

    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. PMID:27533870

  14. 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...

  15. INFLUENCE OF SEDIMENT EXTRACT FRACTIONATION METHODS ON BIOASSAY RESULTS

    EPA Science Inventory

    Four bioassays [Microtax(tm), Mutatox(tm), sister chromatid exchange (SCE), and metabolic cooperation] were used to analyze marine sediment extracts fractionated by two different methods: silica gel column chromatography and acid-base fractionation. esults indicated that a sedime...

  16. 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

    2015-05-01

    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

  17. 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

  18. 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.

  19. 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. PMID:25456225

  20. 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. PMID:26403720

  1. CHARLOTTE HARBOR IR, 2002

    EPA Science Inventory

    The 2002 Charlotte Harbor Implementation Review (IR) summarizes the progress and challenges ahead for the Charlotte Harbor National Estuary Program (CHNEP). The implementation review report requires seven components: Status of CCMP implementation (programmatic progress); Environm...

  2. 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. PMID:11476524

  3. 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.

  4. 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.

  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. 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...

  7. Metal bioavailability in freshwater sediment samples and their influence on ecological status of river basins.

    PubMed

    Roig, Neus; Sierra, Jordi; Moreno-Garrido, Ignacio; Nieto, Elena; Gallego, Elena Pérez; Schuhmacher, Marta; Blasco, Julián

    2016-01-01

    The general aim of this work has been to check the ecological impact of metals on the Ebro river basin. In order to evaluate this, metal behavior considering water, sediment as well as metal bioaccumulation in fish has been studied. Total concentrations of metals, as well as the potentially bioavailable fraction of metals in sediment has also been analyzed by the application of the sequential extraction method (BCR method). In order to evaluate the influence of metal pollution on the river ecological status, according to the Water Framework Directive (WFD), diverse biological indices such as macroinvertebrates (IBMWP), diatoms (IPS) and macrophytes (IVAM), have been considered from an integrated point of view. Considering both water and sediment, metals which contributed in higher extend to the reduction of biological quality have been demonstrated to be Pb and Zn, as they presented a negative influence on macroinvertebrates, diatoms and macrophytes communities. As and Cr that seemed to have a significant influence on macroinvertebrates and diatoms too, while Ni negatively influenced only diatom communities. This study also demonstrated that monitoring programs only based on total metal determination in water are inefficient, as metals present even at undetectable concentrations in water are strongly accumulated in fish. Moreover, the high concentrations of Hg found in sediments indicated that this river basin may present pollution problems regarded to this metal, as demonstrated by the high Hg levels found in fish. PMID:26148425

  8. The influence of sediment type on the distribution of the lesser sandeel, Ammodytes marinus

    NASA Astrophysics Data System (ADS)

    Wright, P. J.; Jensen, H.; Tuck, I.

    2000-12-01

    The lesser sandeel Ammodytes marinus ( Raitt, 1934) is an important component of the North Sea ecosystem and the subject of the largest single species fishery in this region. However, little is known about the distribution of this species outside the areas where they are fished. This study examines the physical characteristics of the habitat of A. marinus in an attempt to predict the distribution of this species. The characteristics and topography of sandeel habitat were described from video observations. Data on abundance, sediment characteristics and depth were collected from benthic sampling programmes around the Shetland Isles. These data were used in a general additive model framework (GAM) to examine the relative significance of physical factors in influencing distribution. This analysis found that A. marinus were absent from sediments with a silt/clay content of >10% and densities declined between fractions from 2 to 10%. The apparent dislike for fine sediments was examined further by means of sediment choice experiments. These experiments confirmed the importance of the fine particle fraction in limiting distribution and indicated that sandeels would not be expected to inhabit such areas. Given the constraints of sediment requirements, densities of sandeels in benthic samples appeared to be influenced by water depth.

  9. Evaluating the influence of spatial resolutions of DEM on watershed runoff and sediment yield using SWAT

    NASA Astrophysics Data System (ADS)

    Reddy, A. Sivasena; Reddy, M. Janga

    2015-10-01

    Digital elevation model (DEM) of a watershed forms key basis for hydrologic modelling and its resolution plays a key role in accurate prediction of various hydrological processes. This study appraises the effect of different DEMs with varied spatial resolutions (namely TOPO 20 m, CARTO 30 m, ASTER 30 m, SRTM 90 m, GEO-AUS 500 m and USGS 1000 m) on hydrological response of watershed using Soil and Water Assessment Tool (SWAT) and applied for a case study of Kaddam watershed in India for estimating runoff and sediment yield. From the results of case study, it was observed that reach lengths, reach slopes, minimum and maximum elevations, sub-watershed areas, land use mapping areas within the sub-watershed and number of HRUs varied substantially due to DEM resolutions, and consequently resulted in a considerable variability in estimated daily runoff and sediment yields. It was also observed that, daily runoff values have increased (decreased) on low (high) rainy days respectively with coarser resolution of DEM. The daily sediment yield values from each sub-watershed decreased with coarser resolution of the DEM. The study found that the performance of SWAT model prediction was not influenced much for finer resolution DEMs up to 90 m for estimation of runoff, but it certainly influenced the estimation of sediment yields. The DEMs of TOPO 20 m and CARTO 30 m provided better estimates of sub-watershed areas, runoff and sediment yield values over other DEMs.

  10. 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

  11. 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.

  12. 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. PMID:26350897

  13. 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

  14. 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

  15. 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. PMID:25937494

  16. Influence of mineralogical and heavy metal composition on natural radionuclide concentrations in the river sediments.

    PubMed

    Suresh, G; Ramasamy, V; Meenakshisundaram, V; Venkatachalapathy, R; Ponnusamy, V

    2011-10-01

    The natural radiation level has been determined for the sediment samples of the Ponnaiyar River with an aim of evaluating the radiation hazard. The mineralogical characterizations of the sediments have been carried out using the Fourier Transform Infrared (FTIR) spectroscopic technique. The relative distribution of major minerals is determined by calculating extinction coefficient. The concentration and spatial distribution of heavy metals (Pb, Cr, Cu, Zn and Ni) have been studied to understand the heavy metal contamination and its level of toxicity. To evaluate the potential toxicity, heavy metal concentrations are compared with different toxicological and geological reference values. The comparison results suggest that the present metals create an adverse effect on the aquatic ecosystems associated with this river. To assess the sediment contamination due to the studied heavy metals, the Pollution Load Index (PLI) is calculated. Multivariate Statistical analyses (Pearson Correlation, Cluster and Factor analysis) were carried out between the parameters obtained from radioactivity, mineralogical and geochemical analysis to know the existing relations. Obtained results showed that the effect of mineralogy on level of radioactivity should be significant. However, mineralogy effect on heavy metal composition in the sediments should be limited, indicating that other factors such as vicinity of the pollution sources are more important. Also, the influence of mineralogical characterization on level of radioactivity is significant, whereas the influence of the heavy metal composition on level of radioactivity should be limited. PMID:21636283

  17. The Influence of Seasonally Changing Groundwater/Surface Water Interaction on the Composition of Sediment Fauna

    NASA Astrophysics Data System (ADS)

    Schmidt, S. I.; Hahn, H. J.; Hatton, T. J.; Woodbury, R. J.; Watson, G. D.

    2005-05-01

    Sediment fauna in both streams and groundwater are crucial to the functioning of sediment processes, and are known to be highly influenced by hydraulics. But how does the seasonal variation of groundwater/surface water interactions influence the faunal composition? This question was addressed in a small Western Australian catchment, where four stream sediment sites and 30 groundwater bores were sampled over the period of one year. Mixed fauna at those sites displaying groundwater/surface water interaction was expected. However, there were virtually no species common to groundwater bores and stream sediment tubes, although they were sampled using the same method. The missing species exchange was probably due to the small pore spaces. Since the hydrological and chemical variety within groundwater sites was surprising, going far beyond gradually changing interactions with surface water, we grouped the groundwater sites into four major hydrogeological classes and looked for patterns with which fauna reflected these groups. In two of these hydrogeological groups (Artesian and concentration zones) no fauna was found at all, while fauna was sampled regularly in discharging and recharging zones. Fauna in groundwater bores also reflected whether groundwater was recharged from precipitation alone or also at least seasonally from the stream.

  18. 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.

  19. 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. PMID:26789366

  20. 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

  1. 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.

  2. Influence of introduced Sonneratia apetala on nutrients and heavy metals in intertidal sediments

    NASA Astrophysics Data System (ADS)

    Li, ruili; chai, minwei; Qiu, guo yu

    2015-04-01

    To investigate the influence of Sonneratia apetala on nutrients and heavy metals in intertidal sediments, core sediments from a S. apetala forest and adjacent mud flat in Futian Nature Reserve (Shenzhen Bay, China) were analyzed. The results showed that total carbon (TC), total nitrogen (TN), and total sulfur (TS) in S. apetala site were higher than mud flat site, indicating its improvement on soil nutrient properties. Concentrations of As (S. apetala: 199.66 μg/g, mud flat: 152.40 μg/g) were higher than probable effect concentrations, suggesting heavy pollution of As in sediments of S. apetala and mud flat sites. Furthermore, compared with mud flat site, sediments from S. apetala site have higher heavy metals, including Cr, Ni, Cu, Zn, As, Cd, Pb, and Hg. Overall, the heavy metals in both sites were in the same order of Zn > As > Hg > Cr > Cu ˜ Pb > Ni > Cd. In S. apetala site, organic matters (TC, TN, and TS) were positively correlated with Cu, Zn, and Hg, different from Cu, Zn, Hg, and Cd in mud flat site, indicating less important role of organic matter in trapping heavy metals. In addition, there were positive correlations among Ni, Cu, Zn, and Cd in S. apetala and mud flat sites, indicating the similar sources mainly from increasing municipal and industrial wastewater discharges.

  3. Spatial Heterogeneity of Bacterial Assemblages in Marine Sediments: The Influence of Deposit Feeding by Balanoglossus aurantiacus .

    NASA Astrophysics Data System (ADS)

    Wilde, S. B.; Plante, C. J.

    2002-07-01

    Densities and substrate utilization patterns of the bacterial assemblages of three intertidal sandflats were contrasted to investigate spatial heterogeneity. Possible influence of deposit-feeding Balanoglossus aurantiacus (Enteropneusta: Ptychoderidae) was also studied by comparing samples taken from the faecal mounds with surrounding sediments. While there were no significant differences in total bacterial abundance, carbon source utilization patterns, determined using Biolog GN microtitre plates, differed among the sandflats and within the sandflats for samples from grids more than 10 m apart. No consistent quantitative or qualitative differences were detected among clusters of ambient sediment samples taken less than 0·5 m apart. Qualitative differences in microbial assemblages were found between faecal mounds and ambient (>10 cm apart) sediment within a single intertidal flat. These differences were in part due to digestive removal of bacteria, as heterotrophic plate counts and response in Biolog plates (average well colour development, AWCD) were significantly higher for the surrounding sediment. However, when Biolog profiles were normalized to AWCD, it became clear that gut passage resulted in structural shifts in bacterial assemblages. These changes were due to digestion of a subset of ingested bacteria with the concomitant stimulation (or inoculation) of other groups, which were largely unculturable under the conditions employed. These findings illustrate that deposit feeding effects spatial heterogeneity in sedimentary bacterial assemblages. Given the ephemeral nature of these disturbed patches, however, it is not yet clear that deposit feeding is a primary determinant of microbial community structure in this sedimentary landscape.

  4. 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. PMID:17051782

  5. 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

  6. 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. PMID:26411339

  7. 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.

  8. 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. PMID:25931175

  9. The influence of particle size on radionuclide activity concentrations in Tejo River sediments.

    PubMed

    Madruga, M J; Silva, L; Gomes, A R; Libânio, A; Reis, M

    2014-06-01

    Sediment samples from Tejo River were analyzed for (228)Ra, (226)Ra, (137)Cs and (40)K by HPGe gamma spectrometry. The activity concentration data were statistically analyzed. The activity concentrations values were in the range of about two orders of magnitude for each radionuclide. The influence of the particle size on the radionuclide concentrations was observed. The different environmental origins of the radionuclides (228)Ra, (226)Ra, (137)Cs and (40)K, in the sediments were demonstrated through correlation analysis. Cluster analysis showed a close relationship between (228)Ra and (226)Ra and a different behavior for (40)K. The data obtained in this study provides useful information on the background radioactivity of the studied area and can be further used for radiological mapping of the Tejo River. PMID:24561724

  10. 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

  11. 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

  12. Integration of Hydrologic, Sediment Yield, Sediment Delivery, Hydrodynamic and Sediment Transport Models in Large Great Lakes Watersheds

    NASA Astrophysics Data System (ADS)

    Brunton, A.; Nairn, R.; Selegean, J.

    2004-12-01

    Computational tools to evaluate surface and subsurface water flow and sediment transport are commonly used by environmental and engineering practitioners. However, different parts of the hydrologic system (e.g. hillslope overland flow, groundwater, river channel flow) are often treated separately and at disparate spatial and temporal scales. Overland flow models typically have no explicit channel representation and vice-versa, making integrated assessments of water and sediment delivery from catchment to channel difficult. This is problematic when appraising the influence of land use change (urbanization, modification of riparian buffer strips, changes in tillage and forestry practices etc.) on catchment sediment movement and river flood hydrographs. A 'budgetary' approach was taken to defining the sources and sinks of water and sediment within large catchments in the Great Lakes area under a variety of land uses. These budgets were derived from existing datasets including digital elevation models, river flow and sediment load records, and dam sedimentation surveys. Numerical models of watershed hydrology and sediment delivery, 2-D river flow and sediment transport were constructed to develop a general understanding of the hydrologic and geomorphic behavior of these systems, and to predict the effects of changing land use and riparian buffer zone modification. Models were calibrated against river flow and sediment transport records, reservoir sedimentation surveys and harbor dredging records. The challenges and benefits of combining these diverse approaches and their implementation in best management practices are discussed.

  13. 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

  14. Sediment Composition Influences Spatial Variation in the Abundance of Human Pathogen Indicator Bacteria within an Estuarine Environment

    PubMed Central

    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. PMID:25397595

  15. 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. PMID:25397595

  16. 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. PMID:21802196

  17. 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.

  18. 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.

  19. A review of sediment dynamics in the Severn Estuary: influence of flocculation.

    PubMed

    Manning, A J; Langston, W J; Jonas, P J C

    2010-01-01

    This paper provides a review and critique of the distributions and characteristics of non-cohesive and cohesive sediments within the Severn Estuary, with particular reference to floc properties. The estuary is hyper-tidal and, consequently, highly turbid along most of its length and it generally has two turbidity maxima. In the upper reaches of the estuary, suspended particulate matter (SPM) concentrations can be in excess of 10 g l(-1) for river flows up to 50 m(3)s(-1), rising to over 50 g l(-1) during periods of lower river flow. The lower estuary turbidity maximum originates in the vicinity of Bridgwater Bay where SPM concentrations may vary between 0.1-200 g l(-1). The formation of fluid mud is coupled to the spring-neap cycle and strong vertical gradients in SPM concentrations produce turbulence damping and drag reduction effects, and hence impair the ability of the flow to transport sediments. Flocculation is an important mechanism for controlling the behaviour of fine sediments and mean settling velocities of flocs vary between 0.8-6 mm s(-1). A secondary consequence of flocculation is the formation of mud:sand mixtures in turbid suspensions. Improved understanding of the significance of flocculation processes is crucial as they may exert an influence on the mechanism by which adsorbed contaminants are transported in the system. PMID:20153485

  20. 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

  1. Influence of sources on plutonium mobility and oxidation state transformations in vadose zone sediments.

    PubMed

    Kaplan, Daniel I; Powell, Brian A; Duff, Martine C; Demirkanli, Deniz I; Denham, Miles; Fjeld, Robert A; Molz, Fred J

    2007-11-01

    Well-defined solid sources of Pu(III) (PuCl3), Pu(IV) (Pu (NO3)4 and Pu (C2O4)2), and Pu(VI) (Pu02(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 Pu(VI)O2(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 studyfrom the Pu(IV)(NO3)4- and Pu(III)(III)Cl3-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

  2. 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

  3. Rare earth elements in coastal sediments of the northern Galician shelf: Influence of geological features

    NASA Astrophysics Data System (ADS)

    Prego, Ricardo; Caetano, Miguel; Bernárdez, Patricia; Brito, Pedro; Ospina-Alvarez, Natalia; Vale, Carlos

    2012-03-01

    The Northern coast of Galicia, NW Iberian Peninsula, exhibits a variety of geological features: Ortegal allochthonous complex, Ollo-de-Sapo autochthonous domain and massifs of Bares, Barqueiro and San-Ciprian. In order to examine the influence of terrestrial lithologies on coastal sediments, 103 samples were collected in the Rias of Ortigueira, Barqueiro and Viveiro, their neighbouring shelf and the estuaries of Mera, Sor and Landro rivers. Aluminium, Fe, Sc, particulate inorganic and organic carbon and rare earth elements (REE) were determined in the <2 mm fraction. In addition, calcite, muscovite, quartz and riebeckite minerals were identified and quantified in 33 selected samples. The distributions of riebeckite and Fe reflect the influence of Ortegal complex on the coastal areas around the Cape Ortegal. The highest concentrations of ΣREE were found in fine sediments from confined inner parts of the Rias (up to 233 mg kg-1), while most of the sands contained 11-70 mg kg-1. ΣREE normalised to European Shale (ES) highlights the relative abundance of lanthanides (ΣREEN>6) near Cape Ortegal and the innermost ria zones. The ratio between light and heavy REE (L/H) showed lower values (4-11) around Cape Ortegal and the shelf while higher ratios (15-23) were detected in west of the Cape Estaca-de-Bares and in the inner Viveiro Ria due to elevated contributions of La and Ce. The L/H values normalised to ES reflects the importance of HREE in the adjacent area to Ortegal Complex (LN/HN<0.8) and the LREE (LN/HN>1.4) in the inner estuaries and west Cape Estaca-de-Bares. The highest REE individual ES normalised were measured in fine-grained sediments of the Mera and Sor estuaries. Sediments from the eastern shelf of Cape Ortegal presented enhanced ratios only for HREE. These results indicate that distribution of REE in the northern Galician region is highly depending on the neighbouring lithological pattern, contrasting with the situation found in the western Galician

  4. 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

  5. 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

  6. 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. PMID:25389752

  7. 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

  8. Influence of sedimentation on the threshold for Soret-driven convection in colloidal suspensions.

    PubMed

    Hadji, L; DarAssi, M

    2014-01-01

    The onset of Soret-driven convection in a horizontal layer of a colloidal suspension is investigated by considering a particulate medium model. We consider a dilute suspension of spherical solid particles being subjected to convection in a Rayleigh-Bénard geometry setup. The mathematical model takes into account the effects of thermophoresis, particle sedimentation, and Brownian diffusion. The equations governing the convective motion consist of the momentum equation which includes an extra body force term to account for the thermophoretic force effect, the conservation of particles equation whose mass-flux term couples the Soret and particle diffusion effects and whose advective term includes the sedimentation force, and the heat and mass balance equations. The horizontal boundaries are assumed rigid, perfectly thermally conducting, and impervious to mass flow. Furthermore, the model makes use of the effective viscosity of the suspension whose dependence on the particle concentration is through Einstein's formula. Moreover, we take into account the decrease of both the coefficient of Brownian diffusion and the mixture thermal diffusion with particle concentration due to the particles hindrance effect. The nondimensionalization leads to the emergence of an experimental parameter, β, which depicts the competition between the effects of thermophoresis, sedimentation, and particle diffusion. The parameter β is a function of the particles radius, the shape of which is an inverted parabola having two zeros. A combination of asymptotic and numerical computations is used to determine the threshold for the onset of the mass dominated convection, which corresponds to 0<β≪1. Our findings shed light on the role of particle sedimentation and particle size, as well as the influence of other processing variables on the fluid instability. PMID:24580327

  9. Influence of calcite and dissolved calcium on uranium(VI) sorption to a hanford subsurface sediment.

    PubMed

    Dong, Wenming; Ball, William P; Liu, Chongxuan; Wang, Zheming; Stone, Alan T; Bai, Jing; Zachara, John M

    2005-10-15

    The influence of calcite and dissolved calcium on U(VI) adsorption was investigated using a calcite-containing sandy silt/clay sediment from the U. S. Department of Energy Hanford site. U(VI) adsorption to sediment, treated sediment, and sediment size fractions was studied in solutions that both had and had not been preequilibrated with calcite, at initial [U(VI)] = 10(-7)-10(-5) mol/L and final pH = 6.0-10.0. Kinetic and reversibility studies (pH 8.4) showed rapid sorption (30 min), with reasonable reversibility in the 3-day reaction time. Sorption from solutions equilibrated with calcite showed maximum U(VI) adsorption at pH 8.4 +/- 0.1. In contrast, calcium-free systems showed the greatest adsorption at pH 6.0-7.2. At pH > 8.4, U(VI) adsorption was identical from calcium-free and calcium-containing solutions. For calcite-presaturated systems, both speciation calculations and laser-induced fluorescence spectroscopic analyses indicated that aqueous U(VI) was increasingly dominated by Ca2UO2(CO3)3(0)(aq) at pH < 8.4 and thatformation of Ca2UO2(CO3)3(0)(aq) is what suppresses U(VI) adsorption. Above pH 8.4, aqueous U(VI) speciation was dominated by UO2(CO3)3(4-) in all solutions. Finally, results also showed that U(VI) adsorption was additive in regard to size fraction but not in regard to mineral mass: Carbonate minerals may have blocked U(VI) access to surfaces of higher sorption affinity. PMID:16295860

  10. Influence of Calcite and Dissolved Calcium on Uranium(VI) Sorption to a Hanford Subsurface Sediment

    SciTech Connect

    Dong, Wenming; Ball, William P.; Liu, Chongxuan; Wang, Zheming; Stone, Alan T.; Bai, Jing; Zachara, John M.

    2005-10-15

    The influence of calcite and dissolved calcium on U(VI) adsorption was investigated using a calcite-containing sandy silt/clay sediment from the U. S. Department of Energy Hanford site. U(VI) adsorption to sediment, treated sediment, and sediment size fractions was studied in solutions that both had and had not been preequilibrated with calcite, at initial [U(VI)] - 10-7-10-5 mol/L and final pH - 6.0-10.0. Kinetic and reversibility studies (pH 8.4) showed rapid sorption (30 min), with reasonable reversibility in the 3-day reaction time. Sorption from solutions equilibrated with calcite showed maximum U(VI) adsorption at pH 8.4-0.1. In contrast, calcium-free systems showed the greatest adsorption at pH 6.0-7.2. At pH > 8.4, U(VI) adsorption was identical from calcium-free and calcium-containing solutions. For calcite-presaturated systems, both speciation calculations and laser-induced fluorescence spectroscopic analyses indicated that aqueous U(VI) was increasingly dominated by Ca2UO2(CO3)3 0(aq) at pH<8.4 and that formation of Ca2UO2(CO3)3 0(aq) is what suppresses U(VI) adsorption. Above pH 8.4, aqueous U(VI) speciation was dominated by UO2(CO3)3 4- in all solutions. Finally, results also showed that U(VI) adsorption was additive in regard to size fraction but not in regard to mineral mass: Carbonate minerals may have blocked U(VI) access to surfaces of higher sorption affinity.

  11. 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

  12. Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China.

    PubMed

    Ma, Long; 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

  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. Total mercury in sediments and in Brazilian Ariidae catfish from two estuaries under different anthropogenic influence.

    PubMed

    Azevedo, Juliana S; Braga, Elisabete S; Favaro, Deborah T; Perretti, Adriana R; Rezende, Carlos Eduardo; Souza, Cristina Maria M

    2011-12-01

    Santos-São Vicente estuary, located in São Paulo State, Brazil, has a history of contamination by inorganic chemicals such as mercury (Hg). In the 1980s the Cubatão was considered one of the most polluted sites in the world as a consequence of the intense industrial activities located in the city close to the estuary. To provide data and evaluate the local biota, total mercury (THg) contents were determined in sediments and in fish, Cathorops spixii, from different areas of the Santos-São Vicente estuary. For comparison, samples were also collected in a non-polluted system with similar hydrochemistry characteristics, the Cananeia estuary. The water characteristics and THg levels in sediment and fish samples confirmed a high human influence in the Santos-São Vicente estuary. The lowest THg values, observed in Cananeia, were evidence of low anthropogenic influence. High values observed in Santos-São Vicente show the necessity for a monitoring program. PMID:22030105

  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. PMID:26598988

  16. 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. PMID:22919346

  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 the sea rush Juncus maritimus on metal concentration and speciation in estuarine sediment colonized by the plant.

    PubMed

    Almeida, C Marisa R; Mucha, Ana P; Vasconcelos, M Teresa S D

    2004-06-01

    Metal accumulation by Juncus maritimus and the role of this plant on the physical and chemical composition of sediments, from the Douro river estuary (NW Portugal), were investigated. The contents of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined (by atomic absorption spectrophotometry) in sediments, rhizosediments (those among plant roots and rhizomes), and different plant tissues (roots, rhizomes, leaves, and stems). Metal fractionation in sediments through sequential extraction was carried out and used for interpretation of sediment/J. maritimus interactions. Two estuarine sites with different characteristics were studied: site I displayed sandy sediment with lower organic matter and metals more weakly bound to it than site II sediment, which was muddy. At both sites, higher metal contents were observed in rhizosediments than in the surrounding sediment, but metals were more weakly bound to rhizosediment. Therefore, J. maritimus markedly influenced the sediments among its roots and rhizomes, changing metal distribution and speciation. Different patterns of both metal uptake and metal distribution among J. maritimus tissues were observed at the two sites. Plant bioaccumulation was only observed for Cd, Cu, and Zn, being similar for Cd atthe two sites and significantly higher for Cu and Zn (9 and 4 times higher, respectively) at site I. In conclusion, J. maritimus was shown to have potential for phytoextraction (or phytostabilization) of Cd, Cu, and Zn in estuarine environment. However, an eventual application of J. maritimus for this purpose will require a periodic removal of the plants together with their own rhizosediment. PMID:15224743

  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. 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

  1. Nutrient Fluxes, Porewater Profiles and Denitrification in Sediment Influenced by Algal Sedimentation and Bioturbation by Monoporeia affinis

    NASA Astrophysics Data System (ADS)

    Tuominen, L.; Mäkelä, K.; Lehtonen, K. K.; Haahti, H.; Hietanen, S.; Kuparinen, J.

    1999-07-01

    The effects of addition of algae (340 mg C m-2) and of the amphipod Monoporeia affinis (1500 ind m-2) on denitrification; porewater nutrient profiles; nutrient fluxes between sediment and water; and bacterial production were studied. A laboratory experiment was conducted using cores filled with sediment from the Gulf of Finland (Baltic Sea). Denitrification (isotope pairing method) was dramatically reduced in the cores enriched with algae (from 200-300 to 10-20 μmol N m-2 day-1). However, the addition of M. affinis together with algae negated this effect. Monoporeia affinis alone increased the coupled nitrification-denitrification as compared to the control cores. Bioturbation by the amphipods oxidised the sediment surface layers and consequently, PO43-concentration in the porewater decreased. In the cores enriched with algae, the loss of N from the sediment porewater was dominated by the efflux of NH4+which formed 90% of the loss. In the M. affinis enriched cores, the share of the NH4+efflux was 60% of which the excretion by M. affinis was 5-10%. The effects of M. affinis were found to be caused mainly by the improved O2conditions in the sediment.

  2. 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

  3. The Influence of Glass Leachate on the Hydraulic, Physical, Mineralogical and Sorptive Properties of Hanford Sediment

    SciTech Connect

    Kaplan, Daniel I.; Serne, R. Jeffrey; Schaef, Herbert T.; Lindenmeier, Clark W.; Parker, Kent E.; Owen, Antionette T.; McCready, David E.; Young, James S.

    2003-08-26

    The Immobilized Low Activity Waste (ILAW) generated from the Hanford Site will be disposed of in a vitrified form. It is expected that leachate from the vitrified waste will have a high pH and high ionic strength. The objective of this study was to determine the influence of glass leachate on the hydraulic, physical, mineralogical, and sorptive properties of Hanford sediments. Our approach was to put solutions of NaOH, a simplified surrogate for glass leachate, in contact with quartz sand, a simplified surrogate for the Hanford subsurface sediment, and Warden soil, an actual Hanford sediment. Following contact with three different concentrations of sodium hydroxide solutions, changes in hydraulic conductivity, porosity, moisture retention, mineralogy, aqueous chemistry, and soil-radionuclide distribution coefficients were determined. Under chemical conditions approaching the most caustic glass leachate conditions predicted in the near-field of the ILAW disposal site, approximated by 0.3 M NaOH, significant changes in mineralogy were observed. The clay minerals of the Hanford sediment evidenced the greatest dissolution thereby increasing the relative proportions of the more resistant minerals, e.g., quartz, feldspar, and calcite, in the remaining mass. Some re-precipitation of solids (mostly amorphous gels) was observed after caustic contact with both solids; these precipitates increased the moisture retention in both sediments, likely because of water retained within the gel coatings. The hydraulic conductivities were slightly lower but, because of experimental artifacts, these reductions should not be considered significant. Thus, there does not seem to be large differences in the hydraulic properties of the quartz sand or Warden silt loam soil after 192 days of contact with caustic fluids similar to glass leachate. The long term projected impact of the increased moisture retention has not been evaluated but likely will not make past simplified performance

  4. 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

  5. Influence of Shimada Seamount on sediment composition in the eastern tropical North Pacific

    NASA Astrophysics Data System (ADS)

    Dean, Walter E.; Gardner, James V.; Parduhn, Nancy L.

    1989-07-01

    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.

  6. 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. PMID:27088626

  7. Oleananes in oils and sediments: Evidence of marine influence during early diagenesis?

    NASA Astrophysics Data System (ADS)

    Murray, Andrew P.; Sosrowidjojo, Imam B.; Alexander, Robert; Kagi, Robert I.; Norgate, Carolyn M.; Summons, Roger E.

    1997-03-01

    The oleananes, as markers for the angiosperms, provide valuable source and age information when present in an oil. Nevertheless, they are not quantitatively related to the land plant input and indeed their presence reflects only a small leak in diagenetic processes leading primarily to aromatic oleanoids. Because they are minor products, the abundance of oleananes in terrigenous oils and sediments may be highly sensitive to changes in early diagenetic conditions. Here we present evidence that contact of plant matter with seawater during early diagenesis enhances the expression of oleananes in a mature sediment or oil. Oleananes are absent or present at very low concentrations in samples from the base of an Eocene coal seam affected by postdepositional seawater intrusion. However, their abundance increases toward the top of the seam in correlation with % organic sulphur, dibenzothiophene/phenanthrene, and the homohopane index. Similarly, in deltaic sediments from the South Sumatra Basin, oleanane/hopane is strongly correlated with indicators of marine influence such as C 27/C 29 steranes and the homohopane index. In each case, increasing oleanane abundance is accompanied by a reduction in the extent of aromatisation and, for the South Sumatra Basin, the proportion of A-ring contracted oleananes. An angiosperm-derived Miocene coal from the Philippines, deposited under freshwater conditions, shows abundant aromatic oleanoids but no oleananes. These results show that oleananes need to be used with caution as age and source markers in fluvio-deltaic and lacustrine petroleum systems. On the other hand, their sensitivity to early diagenetic conditions may make them useful in locating effective source rocks in such systems.

  8. 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

  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. Viscoelastic properties of whole blood. Influence of fast sedimenting red blood cell aggregates.

    PubMed

    Schneditz, D; Rainer, F; Kenner, T

    1987-01-01

    Red blood cell (RBC) aggregation is known to be of deciding influence on erythrocyte sedimentation-rate (ESR) and on whole blood viscoelastic properties. The rheological behaviour of blood collected from a control-group with normal ESR is compared to the viscoelastic behaviour of blood collected from two groups with high to very high ESR, whose individuals are suffering from chronical polyarthritis and Morbus Bechterew, respectively. The rheological properties are evaluated by means of an oscillating-flow capillary-rheometer where the viscous (eta') and elastic (eta") component of the complex viscosity (eta) is measured at a constant frequency of 2 Hz. Correcting for the varying hematocrit of the different blood samples according to an exponential equation, the viscoelastic data are found to be elevated in the groups with high ESR. For the viscous properties this is only due to the increase of the plasma viscosity. A correction for the plasma viscosity, however, shows that the viscous properties at low shear- rates (2s-1) are significantly reduced, whereas elastic properties in a range of medium shear-rates (10s-1 to 50s-1) are significantly increased (P less than 0.001, t-test of Student). This result is discussed to be due to the high packing density of the RBC in fast sedimenting aggregates. High packing density reduces the effective volume of the RBC but increases the stiffness of the aggregates. PMID:3651579

  11. 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. PMID:24954631

  12. 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.

  13. 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.

  14. Distribution patterns and possible influencing factors of As speciation in ornithogenic sediments from the Ross Sea region, East Antarctica.

    PubMed

    Lou, Chuangneng; Liu, Xiaodong; Liu, Wenqi; Wu, Libin; Nie, Yaguang; Emslie, Steven D

    2016-05-15

    Ornithogenic sediments are rich in toxic As (arsenic) compounds, posing a potential threat to local ecosystems. Here we analyzed the distribution of As speciation in three ornithogenic sediment profiles (MB6, BI and CC) collected from the Ross Sea region, East Antarctica. The distributions of total As and total P (phosphorus) concentrations were highly consistent in all three profiles, indicating that guano input is a major factor controlling total As distribution in the ornithogenic sediments. The As found in MB6 and CC is principally As(V) (arsenate), in BI As(III) (arsenite) predominates, but the As in fresh guano is largely composed of DMA (dimethylarsinate). The significant difference of As species between fresh guano and ornithogenic sediment samples may be related to diagenetic processes after deposition by seabirds. Based on analysis of the sedimentary environment in the studied sediments, we found that the redox conditions have an obvious influence on the As speciation distribution. Moreover, the distributions of As(III) and chlorophyll a in the MB6 and BI profiles are highly consistent, demonstrating that aquatic algae abundance may also influence the distribution patterns of As speciation in the ornithogenic sediments. PMID:26930318

  15. Influence of sampling on magnetic susceptibility anisotropy of soft sediments: comparison between gravity and piston cores

    NASA Astrophysics Data System (ADS)

    Shimono, Takaya; Yamazaki, Toshitsugu; Inoue, Seiko

    2014-12-01

    Anisotropy of magnetic susceptibility (AMS) has been used extensively for determining mineral orientatrections. In terms of the sample coordinate, K max declinations in the three gravity cores are oriented along the core-splitting surface, whereas K max declinations in the three piston cores are perpendicular to the splitting surface. We attribute the artificial AMS to the stress created by the deformation of core liners when being split. When interpreting AMS data from sediment cores, it is necessary to investigate the influence of sampling using the sample coordinates. In this paper, we also report over-sampling and under-sampling of piston cores from a comparison of down-core magnetic susceptibility variations between piston and gravity cores. It is noteworthy that under-sampling as well as over-sampling can occur in the uppermost few meters of piston cores.

  16. Do acid volatile sulfides (AVS) influence the accumulation of sediment-bound metals to benthic invertebrates under natural field conditions?

    PubMed

    De Jonge, Maarten; Dreesen, Freja; De Paepe, Josefina; Blust, Ronny; Bervoets, Lieven

    2009-06-15

    The present study evaluates the influence of acid volatile sulfides (AVS) on accumulation of sediment-bound metals in benthic invertebrates under natural field conditions. Natural sediments, pore water, surface water, and two species of widespread benthic invertebrates (Chironomus gr. thummi and Tubifex tubifex) were collected from 17 historical polluted Flemish lowland rivers and measured for metal concentrations. Different sediment characteristics were determined (AVS, organic matter, clay content) and multiple regression was used to study their relationship with accumulated metals in the invertebrates. Physical and chemical analysis of the field samples indicated low metal concentrations in the water and pore water, but very high metal concentrations in the sediment and the invertebrates, especially for Pb (5.99 micromol/ g). In general, metal accumulation in chironomids and tubificid worms was most strongly correlated with total metal concentrations in the sediment and sediment metal concentrations normalized for organic matter and clay content. Following the results of the linear regression model, AVS did not turn out to be a significant variable in describing variation in metal accumulation. Our study clearly demonstrates that, in addition to the results gained from experiments under lab conditions, benthic invertebrates can accumulate metals from unspiked field sediments even when there's an excess of AVS. PMID:19603670

  17. The influence of 70 and 120 kHz tonal signals on the behavior of harbor porpoises (Phocoena phocoena) in a floating pen.

    PubMed

    Kastelein, Ronald A; Verboom, Willem C; Jennings, Nancy; de Haan, Dick; van der Heul, Sander

    2008-09-01

    Two harbor porpoises in a floating pen were subjected to five pure tone underwater signals of 70 or 120 kHz with different signal durations, amplitudes and duty cycles (% of time sound is produced). Some signals were continuous, others were intermittent (duty cycles varied between 8% and 100%). The effect of each signal was judged by comparing the animals' surfacing locations and number of surfacings (i.e. number of respirations) during test periods with those during baseline periods. In all cases, both porpoises moved away from the sound source, but the effect of the signals on respiration rates was negligible. Pulsed 70 kHz signals with a source level (SL) of 137 dB had a similar effect as a continuous 70 kHz signal with an SL of 148 dB (re 1 microPa, rms). Also, a pulsed 70 kHz signal with an SL of 147 dB had a much stronger deterring effect than a continuous 70 kHz signal with a similar SL. For pulsed 70 kHz signals (2 s pulse duration, 4s pulse interval, SL 147 dB re 1 microPa, rms), the avoidance threshold sound pressure level (SPL), in the context of the present study, was estimated to be around 130 dB (re 1 microPa, rms) for porpoise 064 and around 124 dB (re 1 microPa, rms) for porpoise 047. This study shows that ultrasonic pingers (70 kHz) can deter harbor porpoises. Such ultrasonic pingers have the advantage that they do not have a "dinner bell" effect on pinnipeds, and probably have no, or less, effect on other marine fauna, which are often sensitive to low frequency sounds. PMID:18599117

  18. 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.

  19. Influence of quasi-geostrophic currents and inertial waves on the elution of fine sediments in the Southeast Baltic

    NASA Astrophysics Data System (ADS)

    Golenko, M. N.; Golenko, N. N.; Emelyanov, E. M.; Nekrasov, M. A.

    2016-03-01

    Numerical simulation based on the Princeton Ocean Model (POM) was performed for a region of the Southeast Baltic in order to compare data on the spatial distribution of velocity and bottom sediments. Special attention was focused on the influence of western and northeastern winds, which generate intense quasi-geostrophic currents can may cause very high velocities in the near bottom layer, which results in the elution of bottom sediments and transport of their fine fractions. An abrupt change in wind velocity intensifies the effect of elution due to generation of inertial internal waves that penetrate into the bottom layer. The spatial distributions of the velocity in the surface and near bottom layers are compared with data on bottom sediments. It turned out that areas with the highest velocities that formed under the effect of western and northeastern winds in most cases coincide with areas where bottom sediments are represented by coarse-grain fractions of gravel and sands.

  20. Oil droplet interaction with suspended sediment in the seawater column: influence of physical parameters and chemical dispersants.

    PubMed

    Sørensen, Lisbet; Melbye, Alf G; Booth, Andy M

    2014-01-15

    The interaction of dispersed oil droplets with large diameter suspended particulate materials (SPM) has been little studied. In the current study, particle size, oil characteristics and chemical dispersant significantly influence the adsorption of oil droplets to SPM in seawater. Sediments with a smaller particulate size (clay) approaching that of the oil droplets (2-20 μm) adsorbed more oil per gram than sediments with large particle size (sand). Heavier, more polar oils with a high asphaltene content adsorbed more efficiently to SPM than lighter, less polar oils. A decrease in the smaller, more water soluble oil components in the sediment adsorbed oil was observed for all oil types. Addition of chemical dispersant decreased the adsorption of oil droplets to suspended carbonate sand in an exponential-like manner. No change in the relative distribution of compounds adsorbed to the sediment was observed, indicating dispersants do not alter the dissolution of compounds from oil droplets. PMID:24257650

  1. 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.

  2. Resolving the influence of nitrogen abundances on sediment organic matter in macrophyte-dominated lakes, using fluorescence spectroscopy.

    PubMed

    Yao, Xin; Wang, Shengrui; Jiao, Lixin; Yan, Caihong; Jin, Xiangcan

    2015-01-01

    A controlled experiment was designed to resolve the influence of nitrogen abundance on sediment organic matters in macrophyte-dominated lakes using fluorescence analysis. Macrophyte biomass showed coincident growth trends with time, but different variation rates with nitrogen treatment. All plant growth indexes with nitrogen addition (N, NH4Cl 100, 200, 400mg/kg, respectively) were lower than those of the control group. Four humic-like components, two autochthonous tryptophan-like components, and one autochthonous tyrosine-like component were identified using the parallel factor analysis model. The results suggested that the relative component changes of fluorescence in the colonized sediments were in direct relation to the change of root biomass with time. In the experiment, the root formation parameters of the plants studied were significantly affected by adding N in sediments, which may be related to the reason that the root growth was affected by N addition. Adding a low concentration of N to sediments can play a part in supplying nutrients to the plants. However, the intensive uptake of NH4(+) may result in an increase in the intracellular concentration of ammonia, which is highly toxic to the plant cells. Hence, our experiment results manifested that organic matter cycling in the macrophyte-dominated sediment was influenced by nitrogen enrichment through influencing vegetation and relevant microbial activity. PMID:25597678

  3. Channel evolution and hydrologic variations in the Colorado River basin: Factors influencing sediment and salt loads

    USGS Publications Warehouse

    Gellis, A.; Hereford, R.; Schumm, S.A.; Hayes, B.R.

    1991-01-01

    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. ?? 1991.

  4. 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

  5. The influence of the macro-sediment from the mountainous area to the river morphology in Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, S. C.; Wu, C.; Shih, P.

    2012-12-01

    Chen, Su-Chin scchen@nchu.edu.tw Wu, Chun-Hung* chwu@mail.nchu.edu.tw Dept. Soil & Water Conservation, National Chung Hsing University, Taichung, Taiwan. The Chenyulan River was varied changed with the marco-sediment yielded source area, Shenmu watershed, with 10 debris flow events in the last decade, in Central Taiwan. Multi-term DEMs, the measurement data of the river topographic profile and aerial photos are adopted to analyze the decade influences of the marco-sediment to the river morphology in Chenyulan River. The changes of river morphology by observing the river pattern, calculating the multi-term braided index, and estimating the distribution of sediment deposition and main channel in the river. The response for the macro-sediment from the mountainous areas into the river in the primary stage is the increase in river width, the depth of sediment deposition and volume of sediment transport. The distribution of sediment deposition from upstream landslide and river bank erosion along the river dominates the change of river morphology in the primary stage. The river morphology achieves stable gradually as the river discharge gradually decreases in the later stage. Both of the braided index and the volume of sediment transport decrease, and the river flow maintains in a main channel instead of the braided pattern in this stage. The decade sediment deposition depth is estimated as > 0.5 m, especially > 3.5 m in the sections closed to the sediment-yield source areas, the mean river width increases 15%, and the sediment with a total volume of 8×107 tons has been transported in last decade in Chenyulan River. The river morphology in Chenyulan River maintains a short-term stable, i.e. 2 or 3 years, and changes again because of the flooding events with a large amount of sediment caused by frequently heavy rainfall events in Taiwan. Furthermore, the response of river morphology in Chenyulan River due to the heavy rainfall with a total precipitation of around 860 mm

  6. 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

  7. 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.

  8. 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., Jr.; 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.

  9. Influence of a dam on fine-sediment storage in a canyon river

    USGS Publications Warehouse

    Hazel, J.E., Jr.; 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.

  10. Influence of allochtonous carbon input and food-web structure on freshwater biotic communities and sedimentation process

    NASA Astrophysics Data System (ADS)

    Harrault, Loïc; Allard, Béatrice; Mériguet, Jacques; Carmignac, David; Perret, Samuel; Huon, Sylvain; Edeline, Eric; Lacroix, Gérard

    2013-04-01

    Soil erosion in freshwaters induces important changes in lake metabolism. The organic matter and the nutrients supplied by soil inputs can change internal biogeochemical cycles and subsidize the whole food web from basal organisms to top-predators. Since the last two decades, the role of allochthonous organic matter as a basal resource for aquatic food webs in natural and controlled conditions has received a growing attention. We studied the impact of soil on the functioning of pond ecosystems by performing monthly additions of soil in freshwater mesocosms. In addition, the food-web structure was manipulated by addition of omnivorous fish to study interactions between the bottom-up effect of soil addition and the top-down effect of fish. The effects of soil and fish addition on the, the elemental and the biochemical compositions of pelagic compartments and recent sediment, on the biomass of seston and zooplankton and on the sediment rates were studied. Soil inputs had no effect on biomass, stoichiometry and lipid composition of seston and zooplankton but fish growth was enhanced by soil addition. Soil treatment had several (but idiosyncratic) effects on the stoichiometry and on the lipid composition of recent sediment. However, the sedimentation rates and the potential biodegradability of recent sediment were not affected by soil inputs. Fish addition affected chlorophyll-a concentration of the water column, seston biomass, sedimentation rates and stoichiometry of seston, zooplankton and short-term sediment. The lipid composition of recent sediment was also influenced by fish addition. However, fish addition did not change the biodegradability of recent sediment. Finally, we did not observe any significant interaction between soil and fish treatments. Our results suggest that the addition of soil as allochthonous inputs to aquatic ecosystem induced a subsidize of the food web only on fish, probably due to direct foraging on bottom sediment. Nevertheless, this