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Sample records for air soil sediment

  1. Revisiting Atmospheric Lead in NYC - Comparison of Archived Air Filters to Urban Park Sediments and Soils

    NASA Astrophysics Data System (ADS)

    Chillrud, S. N.; Ross, J. M.; Yan, B.; Bopp, R.

    2015-12-01

    Urban lake sediments have the potential to be used for reconstructing history of aerosols, providing data before the start of urban air quality monitoring. In a previous study, the similarity between radionuclide and excess Pb inventories (57 g/m^2) in Central Park Lake (CPL) sediments and those same parameters in Central Park soils (CPS) was interpreted to indicate that urban lake sediment cores from CPL represent deposition of atmospheric aerosols over the history of the park, which was constructed in the 1860s. Furthermore, metal ratios and metal chronologies indicated that incineration was the major source of Pb to the NYC atmosphere over the 20th century. In this report, we compare the lake chronologies for metals to a set of archived air filters collected by the Department of Energy's Environmental Measurement Lab (EML). These weekly filters of total suspended particulates (TSP) were collected by a high volume sampler located in lower Manhattan for radionuclides as part of the program focused on documenting radioactive fallout from nuclear weapons testing. Metal concentrations measured in subsamples of the EML filters collected between the 1970s to 1990s showed Pb decreasing more slowly than the records of Pb added to gasoline. Metal ratios in the filters were similar to the ratios measured in CPL sediments; the Pb to Sn ratios were roughly 20:1 and the Pb to Zn ratios were in close to 1. The similarity of the ratios provides additional solid support that the CP Lake sediment cores reflect atmospheric inputs. The enrichment of Pb in the large aerosol particle fraction (TSP), relative to fine PM2.5 fraction, demonstrates that the resuspended NYC soils and their historical contaminant burden, are the primary, current source of Pb to NYC air.

  2. Reliable quantification of phthalates in environmental matrices (air, water, sludge, sediment and soil): a review.

    PubMed

    Net, Sopheak; Delmont, Anne; Sempéré, Richard; Paluselli, Andrea; Ouddane, Baghdad

    2015-05-15

    Because of their widespread application, phthalates or phthalic acid esters (PAEs) are ubiquitous in the environment. Their presence has attracted considerable attention due to their potential impacts on ecosystem functioning and on public health, so their quantification has become a necessity. Various extraction procedures as well as gas/liquid chromatography and mass spectrometry detection techniques are found as suitable for reliable detection of such compounds. However, PAEs are ubiquitous in the laboratory environment including ambient air, reagents, sampling equipment, and various analytical devices, that induces difficult analysis of real samples with a low PAE background. Therefore, accurate PAE analysis in environmental matrices is a challenging task. This paper reviews the extensive literature data on the techniques for PAE quantification in natural media. Sampling, sample extraction/pretreatment and detection for quantifying PAEs in different environmental matrices (air, water, sludge, sediment and soil) have been reviewed and compared. The concept of "green analytical chemistry" for PAE determination is also discussed. Moreover useful information about the material preparation and the procedures of quality control and quality assurance are presented to overcome the problem of sample contamination and these encountered due to matrix effects in order to avoid overestimating PAE concentrations in the environment. PMID:25723871

  3. Results of soil, ground-water, surface-water, and streambed-sediment sampling at Air Force Plane 85, Columbus, Ohio, 1996

    USGS Publications Warehouse

    Parnell, J.M.

    1997-01-01

    The U.S. Geological Survey (USGS), in cooperation with Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, prepared the Surface- and Ground- Water Monitoring Work Plan for Air Force Plant 85 (AFP 85 or Plant), Columbus, Ohio, under the Air Force Installation Restoration Program to characterize any ground-water, surface-water, and soil contamination that may exist at AFP 85. The USGS began the study in November 1996. The Plant was divided into nine sampling areas, which included some previously investi gated study sites. The investigation activities included the collection and presentation of data taken during drilling and water-quality sampling. Data collection focused on the saturated and unsatur ated zones and surface water. Twenty-three soil borings were completed. Ten monitoring wells (six existing wells and four newly constructed monitoring wells) were selected for water-quality sam pling. Surface-water and streambed-sediment sampling locations were chosen to monitor flow onto and off of the Plant. Seven sites were sampled for both surface-water and streambed-sediment quality. This report presents data on the selected inorganic and organic constituents in soil, ground water, surface water, and streambed sediments at AFP 85. The methods of data collection and anal ysis also are included. Knowledge of the geologic and hydrologic setting could aid Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, and its governing regulatory agencies in future remediation studies.

  4. Estimating persistence of brominated and chlorinated organic pollutants in air, water, soil, and sediments with the QSPR-based classification scheme.

    PubMed

    Puzyn, T; Haranczyk, M; Suzuki, N; Sakurai, T

    2011-02-01

    We have estimated degradation half-lives of both brominated and chlorinated dibenzo-p-dioxins (PBDDs and PCDDs), furans (PBDFs and PCDFs), biphenyls (PBBs and PCBs), naphthalenes (PBNs and PCNs), diphenyl ethers (PBDEs and PCDEs) as well as selected unsubstituted polycyclic aromatic hydrocarbons (PAHs) in air, surface water, surface soil, and sediments (in total of 1,431 compounds in four compartments). Next, we compared the persistence between chloro- (relatively well-studied) and bromo- (less studied) analogs. The predictions have been performed based on the quantitative structure-property relationship (QSPR) scheme with use of k-nearest neighbors (kNN) classifier and the semi-quantitative system of persistence classes. The classification models utilized principal components derived from the principal component analysis of a set of 24 constitutional and quantum mechanical descriptors as input variables. Accuracies of classification (based on an external validation) were 86, 85, 87, and 75% for air, surface water, surface soil, and sediments, respectively. The persistence of all chlorinated species increased with increasing halogenation degree. In the case of brominated organic pollutants (Br-OPs), the trend was the same for air and sediments. However, we noticed that the opposite trend for persistence in surface water and soil. The results suggest that, due to high photoreactivity of C-Br chemical bonds, photolytic processes occurring in surface water and soil are able to play significant role in transforming and removing Br-OPs from these compartments. This contribution is the first attempt of classifying together Br-OPs and Cl-OPs according to their persistence, in particular, environmental compartments. PMID:20386980

  5. Hydroxyatrazine in soils and sediments

    USGS Publications Warehouse

    Lerch, R.N.; Thurman, E.M.; Blanchard, P.E.

    1999-01-01

    Hydroxyatrazine (HA) is the major metabolite of atrazine in most surface soils. Knowledge of HA sorption to soils, and its pattern of stream water contamination suggest that it is persistent in the environment. Soils with different atrazine use histories were collected from four sites, and sediments were collected from an agricultural watershed. Samples were exhaustively extracted with a mixed-mode extractant, and HA was quantitated using high performance liquid chromatography with UV detection. Atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were also measured in all samples. Concentrations of HA were considerably greater than concentrations of atrazine, DEA, and DIA in all soils and sediments studied. Soil concentrations of HA ranged from 14 to 640 ??g/kg with a median concentration of 84 ??g/kg. Sediment concentrations of HA ranged from 11 to 96 ??g/kg, with a median concentration of 14 ??g/kg. Correlations of HA and atrazine concentrations to soil properties indicated that HA levels in soils were controlled by sorption of atrazine. Because atrazine hydrolysis is known to be enhanced by sorption and pH extremes, soils with high organic matter (OM) and clay content and low pH will result in greater atrazine sorption and subsequent hydrolysis. Significant correlation of HA concentrations to OM, pH, and cation exchange capacity of sediments indicated that mixed-mode sorption (i.e., binding by cation exchange and hydrophobic interactions) was the mechanism controlling HA levels in sediment. The presence of HA in soils and stream sediments at the levels observed support existing hypotheses regarding its transport in surface runoff. These results also indicated that persistence of HA in terrestrial and aquatic ecosystems is an additional risk factor associated with atrazine usage.

  6. Sea to land transfer of anthropogenic radionuclides to the North Wales coast, Part I: external gamma radiation and radionuclide concentrations in intertidal sediments, soil and air.

    PubMed

    Bryan, S E; McDonald, P; Hill, R; Wilson, R C

    2008-01-01

    Previous projects specifically aimed at performing radiological assessments in the vicinity of North Wales, investigating the presence and transfer of radionuclides from sea to land, were in 1986 and 1989. Since then, changes have occurred in the radioactive discharges from the British Nuclear Group Sellafield site. Annual discharges of (137)Cs, (238)Pu, (239,340)Pu and (241)Am have decreased markedly whereas, up until recent years, discharges of (99)Tc have increased. It is therefore desirable to quantify current transfer processes of radionuclides in the North Wales region and thus provide an update on 15-year-old studies. A field campaign was conducted collecting soil samples from 10 inland transects and air particulates on air filters from three High Volume Air Samplers, along the northern coast of Wales at Amlwch, Bangor Pier and Flint. Complementary field data relating to external gamma dose rates were collected at the soil sites. The field data generated for (137)Cs, (238)Pu, (239,340)Pu and (241)Am were consistent with what had been reported 15 years previously. Therefore, there has been no increase in the supply of these Sellafield-derived radionuclides to the terrestrial environment of the North Wales coast. The (99)Tc data in sediments were consistent with reported values within annual monitoring programmes, however, a relatively high activity concentration was measured in one sediment sample. This site was further investigated to determine the reason why such a high value was found. At present there is no clear evidence as to why this elevated concentration should be present, but the role of seaweed and its capacity in accumulating (99)Tc and transferring it to sediment is of interest. The analysis of the field samples for (99)Tc, (137)Cs, (238)Pu, (239,240)Pu and (241)Am has provided a data set that can be used for the modelling of the transfer of anthropogenic radionuclides from sea to land and its subsequent radiological implications and is reported

  7. Nitrogen Species in Soil, Sediment, and Ground Water at a Former Sewage-Treatment Wastewater Lagoon: Naval Air Station Whidbey Island, Island County, Washington

    USGS Publications Warehouse

    Cox, S.E.; Dinicola, R.S.; Huffman, R.L.

    2007-01-01

    The potential for contamination of ground water from remnant sewage sludge in re-graded sediments of a deconstructed sewage-treatment lagoon was evaluated. Ground-water levels were measured in temporary drive-point wells, and ground-water samples were collected and analyzed for nutrients and other water-quality characteristics. Composite soil and sediment samples were collected and analyzed for organic carbon and nitrogen species. Multiple lines of evidence, including lack of appreciable organic matter in sediments of the former lagoon, agronomic analysis of nitrogen, the sequestration of nitrogen in the developing soils at the former lagoon, and likely occurrence of peat deposits within the aquifer material, suggest that the potential for substantial additions of nitrogen to ground water beneath the former sewage lagoon resulting from remnant sewage sludge not removed from the former lagoon are small. Concentrations of nitrogen species measured in ground-water samples were small and did not exceed the established U.S. Environmental Protection Agency's maximum contaminant levels for nitrate (10 milligrams per liter). Concentrations of nitrate in ground-water samples were less than the laboratory reporting limit of 0.06 milligram per liter. Seventy to 90 percent of the total nitrogen present in ground water was in the ammonia form with a maximum concentration of 7.67 milligrams per liter. Concentrations of total nitrogen in ground water beneath the site, which is the sum of all forms of nitrogen including nitrate, nitrite, ammonia, and organic nitrogen, ranged from 1.15 to 8.44 milligrams per liter. Thus, even if all forms of nitrogen measured in ground water were converted to nitrate, the combined mass would be less than the maximum contaminant level. Oxidation-reduction conditions in ground water beneath the former sewage lagoon were reducing. Given the abundant supply of ambient organic carbon in the subsurface and in ground water at the former lagoon, any

  8. Soil conservation through sediment trapping: A review

    NASA Astrophysics Data System (ADS)

    Mekonnen, Mulatie; Keesstra, Saskia; Baartman, Jantiene; Maroulis, Jerry; Stroosnijder, Leo

    2014-05-01

    Preventing the off-site effects of soil erosion is an essential part of good catchment management. Most efforts are in the form of on-site soil and water conservation measures. However, sediment trapping (ST) can be an alternative (or additional) measure to prevent the negative off-site effects of soil erosion. Therefore, not all efforts should focus solely on on-site soil conservation, but also on the safe routing of sediment-laden flows and on creating sites and conditions where sediment can be trapped, preferably in a cost effective or even profitable way. ST can be applied on-site (in-field) and off-site and involves both vegetative and structural measures. The main vegetative measures include grass strips, tree or bush buffers, grassed waterways and restoration of the waterways and their riparian zone; while structural measures include terraces, ponds and check dams. This paper provides a review of studies that have assessed the sediment trapping efficacy (STE) of such vegetative and structural measures. Vegetation type and integration of two or more measures (vegetative as well as structural) are important factors influencing STE. In this review, the STE of most measures was evaluated either individually or in such combinations. In real landscape situations, it is not only important to select the most efficient erosion control measures, but also to determine their optimum location in the catchment. Hence, there is a need for research that shows a more integrated determination of STE at the catchment scale. If integrated measures are implemented at the most appropriate spatial locations within a catchment where they can disconnect landscape units from each other, they will decrease runoff velocity and sediment transport and, subsequently, reduce downstream flooding and sedimentation problems. KEY WORDS: Integrated sediment trapping, sediment trapping efficacy, vegetative, structural, on-site and off-site measures.

  9. Air emissions from exposed contaminated sediments and dredged material

    SciTech Connect

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

    1999-01-01

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

  10. A probe for sampling interstitial waters of stream sediments and bog soils

    USGS Publications Warehouse

    Nowlan, G.A.; Carollo, C.

    1974-01-01

    A probe for sampling interstitial waters of stream sediments and bog soils is described. Samples can be obtained within a stratigraphic interval of 2-3 cm, to a depth of 60-80 cm, and with little or no contamination of the samples by sediment or air. ?? 1974.

  11. Adsorption and desorption of chlorpyrifos to soils and sediments.

    PubMed

    Gebremariam, Seyoum Yami; Beutel, Marc W; Yonge, David R; Flury, Markus; Harsh, James B

    2012-01-01

    Chlorpyrifos, one of the most widely used insecticides, has been detected in air, rain, marine sediments, surface waters, drinking water wells, and solid and liquid dietary samples collected from urban and rural areas. Its metabolite, TCP, has also been widely detected in urinary samples collected from people of various age groups. With a goal of elucidating the factors that control the environmental contamination, impact, persistence, and ecotoxicity of chlorpyrifos, we examine, in this review, the peer-reviewed literature relating to chlorpyrifos adsorption and desorption behavior in various solid-phase matrices. Adsorption tends to reduce chlorpyrifos mobility, but adsorption to erodible particulates, dissolved organic matter, or mobile inorganic colloids enhances its mobility. Adsorption to suspended sediments and particulates constitutes a major off-site migration route for chlorpyrifos to surface waters, wherein it poses a potential danger to aquatic organisms. Adsorption increases the persistence of chlorpyrifos in the environment by reducing its avail- ability to a wide range of dissipative and degradative forces, whereas the effect of adsorption on its ecotoxicity is dependent upon the route of exposure. Chlorpyrifos adsorbs to soils, aquatic sediments, organic matter, and clay minerals to differing degrees. Its adsorption strongly correlates with organic carbon con- tent of the soils and sediments. A comprehensive review of studies that relied on the batch equilibrium technique yields mean and median Kd values for chlorpyrifos of 271 and 116 L/kg for soils, and 385 and 403 L/kg for aquatic sediments. Chlorpyrifos adsorption coefficients spanned two orders of magnitude in soils. Normalizing the partition coefficient to organic content failed to substantially reduce variability to commonly acceptable level of variation. Mean and median values for chlorpyrifos partition coefficients normalized to organic carbon, K, were 8,163 and 7,227 L/kg for soils and 13

  12. Sonochemical Digestion of Soil and Sediment Samples

    SciTech Connect

    Sinkov, Sergei I.; Lumetta, Gregg J.

    2006-10-12

    This work was performed as part of a broader effort to automate analytical methods for determination of plutonium and other radioisotopes in environmental samples. The work described here represented a screening study to determine the potential for applying ultrasonic irradiation to sample digestion. Two standard reference materials (SRMs) were used in this study: Columbia River Sediment and Rocky Flats Soil. The key experiments performed are listed below along with a summary of the results. The action of nitric acid, regardless of its concentration and liquid-to-solid ratio, did not achieve dissolution efficiency better that 20%. The major fraction of natural organic matter (NOM) remained undissolved by this treatment. Sonication did not result in improved dissolution for the SRMs tested. The action of hydrofluoric acid at concentrations of 8 M and higher achieved much more pronounced dissolution (up to 97% dissolved for the Rocky Flats soil sample and up to 78% dissolved for the Columbia River Sediment sample). Dissolution efficiency remains constant for solid-to-liquid ratios of up to 0.05 to 1 and decreases for the higher loadings of the solid phase. Sonication produced no measurable effect in improving the dissolution of the samples compared with the control digestion experiments. Combined treatment of the SRM by mixtures of HNO3 and HF showed inferior performance compared with the HF alone. An adverse effect of sonication was found for the Rocky Flats soil material, which became more noticeable at higher HF concentrations. Sonication of the Columbia River sediment samples had no positive effect in the mixed acid treatment. The results indicate that applying ultrasound in an isolated cup horn configuration does not offer any advantage over conventional ''heat and mix'' treatment for dissolution of the soil and sediment based on the SRM examined here. This conclusion, however, is based on an approach that uses gravimetric analysis to determine gross dissolution

  13. DEMONSTRATION BULLETIN: SOIL/SEDIMENT WASHING SYSTEM BERGMANN USA

    EPA Science Inventory

    The Bergmann USA Soil/Sediment Washing System is a waste minimization technique designed to separate or "partition" soils and sediments by grain size and density. In this water-based volume reduction process, hazardous contaminants are concentrated into a small residual portion...

  14. BERGMANN USA SOIL SEDIMENT WASHING TECHNOLOGY - APPLICATIONS ANALYSIS REPORT

    EPA Science Inventory

    This document provides an evaluation of the performance of the Bergmann USA Soil/Sediment Washing System and its applicability for the treatment of soils or sediments contaminated with organic and/or inorganic compounds. Both the technical and economic aspects of the technology w...

  15. Harmonization of environmental quality objectives for air, water and soil

    SciTech Connect

    Plassche, E.J. van de

    1994-12-31

    Environmental quality objectives (EQO) are often derived for single compartments only. However, concentrations at or below EQO level for one compartment may lead to exceeding of the EQO in another compartment due to intermedia transport of the chemical. Hence, achieving concentrations lower than the EQO in e.g. air does not necessarily mean that a ``safe`` concentration in soil can be maintained because of deposition from air to soil. This means that EQOs for air, water and soil must be harmonized in such a way that they meet a coherence criterion. This criterion implies that a EQO for one compartment has to be set at a level that full protection to organisms living in other compartments is ensured. In The Netherlands a project has been started to derive harmonized EQOs for a large number of chemicals. First, EQ0s are derived for all compartments based on ecotoxicological data for single species applying extrapolation methods. Secondly, these independently derived EQOs are harmonized. For harmonization of EQOs for water, sediment and soil the equilibrium partitioning method is used. For harmonization of EQOs for water and soil with the E00s for air a procedure is used applying computed steady state concentration ratios rather than equilibrium partitioning. The model SimpleBox is used for these computations. Some results of the project mentioned above will be presented. Attention will be paid to the derivation of independent EQ0s as well as the harmonization procedures applied.

  16. Emergence and fate of cyclic volatile polydimethylsiloxanes (D4, D5) in municipal waste streams: release mechanisms, partitioning and persistence in air, water, soil and sediments.

    PubMed

    Surita, Sharon C; Tansel, Berrin

    2014-01-15

    Siloxane use in consumer products (i.e., fabrics, paper, concrete, wood, adhesive surfaces) has significantly increased in recent years due to their excellent water repelling and antimicrobial characteristics. The objectives of this study were to evaluate the release mechanisms of two siloxane compounds, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5), which have been detected both at landfills and wastewater treatment plants, estimate persistence times in different media, and project release quantities over time in relation to their increasing use. Analyses were conducted based on fate and transport mechanisms after siloxanes enter waste streams. Due to their high volatility, the majority of D4 and D5 end up in the biogas during decomposition. D5 is about ten times more likely to partition into the solid phase (i.e., soil, biosolids). D5 concentrations in the wastewater influent and biogas are about 16 times and 18 times higher respectively, in comparison to the detected levels of D4.

  17. Emergence and fate of cyclic volatile polydimethylsiloxanes (D4, D5) in municipal waste streams: release mechanisms, partitioning and persistence in air, water, soil and sediments.

    PubMed

    Surita, Sharon C; Tansel, Berrin

    2014-01-15

    Siloxane use in consumer products (i.e., fabrics, paper, concrete, wood, adhesive surfaces) has significantly increased in recent years due to their excellent water repelling and antimicrobial characteristics. The objectives of this study were to evaluate the release mechanisms of two siloxane compounds, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5), which have been detected both at landfills and wastewater treatment plants, estimate persistence times in different media, and project release quantities over time in relation to their increasing use. Analyses were conducted based on fate and transport mechanisms after siloxanes enter waste streams. Due to their high volatility, the majority of D4 and D5 end up in the biogas during decomposition. D5 is about ten times more likely to partition into the solid phase (i.e., soil, biosolids). D5 concentrations in the wastewater influent and biogas are about 16 times and 18 times higher respectively, in comparison to the detected levels of D4. PMID:24012894

  18. Human viruses in sediments, sludges, and soils*

    PubMed Central

    Rao, V. Chalapati; Metcalf, Theodore G.; Melnick, Joseph L.

    1986-01-01

    Recent studies have provided a greater understanding of the movement of viruses in the environment by their attachment to solids. These studies have focused on solids-associated viruses present in wastewater discharged into the ocean and on viruses in sludge and wastewater that may be retained in soil following their land disposal. Such ocean or land disposal of wastewater and sludge may result in a discharge of one or more of 120 human enteric virus pathogens including those causing poliomyelitis, viral hepatitis A and acute gastroenteritis. Solids-associated viruses in effluents discharged into coastal waters accumulate in bottom sediments, which may contain 10 to 10 000 more virus per unit volume than the overlying seawater. Solids-associated viruses resuspended by water turbulence may be transported from polluted to distant non-polluted recreational or shellfish-growing water. Transmission of viruses causing hepatitis or gastroenteritis may result from contact by bathers or swimmers with these viruses in recreational waters, or from ingestion of raw or improperly cooked shellfish in which the solids-associated virus had been bioaccumulated. The land disposal of sludge and wastewater has a potential of causing infections in farm workers, contamination of crops, pollution of raw potable water sources or infiltration of ground water. Viruses retained on soils can be released by rain water and may contaminate ground water through lateral and vertical movements. PMID:3015442

  19. The Effects of Bioturbation on Soil Processes and Sediment Transport

    NASA Astrophysics Data System (ADS)

    Gabet, Emmanuel J.

    Plants and animals exploit the soil for food and shelter and, in the process, affect it in many different ways. For example, uprooted trees may break up bedrock, transport soil downslope, increase the heterogeneity of soil respiration rates, and inhibit soil horizonation. In this contribution, we review previously published papers that provide insights into the process of bioturbation. We focus particularly on studies that allow us to place bioturbation within a quantitative framework that links the form of hillslopes with the processes of sediment transport and soil production. Using geometrical relationships and data from others' work, we derive simple sediment flux equations for tree throw and root growth and decay.

  20. Subsurface sediment contamination during borehole drilling with an air-actuated down-hole hammer.

    PubMed

    Malard, Florian; Datry, Thibault; Gibert, Janine

    2005-10-01

    Drilling methods can severely alter physical, chemical, and biological properties of aquifers, thereby influencing the reliability of water samples collected from groundwater monitoring wells. Because of their fast drilling rate, air-actuated hammers are increasingly used for the installation of groundwater monitoring wells in unconsolidated sediments. However, oil entrained in the air stream to lubricate the hammer-actuating device can contaminate subsurface sediments. Concentrations of total hydrocarbons, heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd), and nutrients (particulate organic carbon, nitrogen, and phosphorus) were measured in continuous sediment cores recovered during the completion of a 26-m deep borehole drilled with a down-hole hammer in glaciofluvial deposits. Total hydrocarbons, Cu, Ni, Cr and particulate organic carbon (POC) were all measured at concentrations far exceeding background levels in most sediment cores. Hydrocarbon concentration averaged 124 +/- 118 mg kg(-1) dry sediment (n = 78 samples) with peaks at depths of 8, 14, and 20 m below the soil surface (maximum concentration: 606 mg kg(-1)). The concentrations of hydrocarbons, Cu, Ni, Cr, and POC were positively correlated and exhibited a highly irregular vertical pattern, that probably reflected variations in air loss within glaciofluvial deposits during drilling. Because the penetration of contaminated air into the formation is unpreventable, the representativeness of groundwater samples collected may be questioned. It is concluded that air percussion drilling has strong limitations for well installation in groundwater quality monitoring surveys.

  1. Air permeability and trapped-air content in two soils

    USGS Publications Warehouse

    Stonestrom, D.A.; Rubin, J.

    1989-01-01

    To improve understanding of hysteretic air permeability relations, a need exists for data on the water content dependence of air permeability, matric pressure, and air trapping (especially for wetting-drying cycles). To obtain these data, a special instrument was designed. The instrument is a combination of a gas permeameter (for air permeability determination), a suction plate apparatus (for retentivity curve determination), and an air pycnometer (for trapped-air-volume determination). This design allowed values of air permeability, matric pressure, and air trapping to be codetermined, i.e., determined at the same values of water content using the same sample and the same inflow-outflow boundaries. Such data were obtained for two nonswelling soils. -from Authors

  2. Global Soil and Sediment transfer during the Anthropocene

    NASA Astrophysics Data System (ADS)

    Hoffmann, Thomas; Vanacker, Veerle; Stinchcombe, Gary; Penny, Dan; Xixi, Lu

    2016-04-01

    The vulnerability of soils to human-induced erosion and its downstream effects on fluvial and deltaic ecosystems is highly variable in space and time; dependent on climate, geology, the nature and duration of land use, and topography. Despite our knowledge of the mechanistic relationships between erosion, sediment storage, land-use and climate change, the global patterns of soil erosion, fluvial sediment flux and storage throughout the Holocene remain poorly understood. The newly launched PAGES working group GloSS aims to determine the sensitivity of soil resources and sediment routing systems to varying land use types during the period of agriculture, under contrasting climate regimes and socio-ecological settings. Successfully addressing these questions in relation to the sustainable use of soils, sediments and river systems requires an understanding of past human-landscape interactions. GloSS, therefore, aims to: Develop proxies for, or indices of, human impact on rates of soil erosion and fluvial sediment transfer that are applicable on a global scale and throughout the Holocene; Create a global database of long-term (102-104 years) human-accelerated soil erosion and sediment flux records; Identify hot spots of soil erosion and sediment deposition during the Anthropocene, and Locate data-poor regions where particular socio-ecological systems are not well understood, as strategic foci for future work. This paper will present the latest progress of the PAGES GloSS working group.

  3. Metal uptake from soils and soil-sediment mixtures by larvae of Tenebrio molitor (L.) (Coleoptera).

    PubMed

    Vijver, Martina; Jager, Tjalling; Posthuma, Leo; Peijnenburg, Willie

    2003-03-01

    Bioassays were performed to evaluate the impact of soil characteristics on Cd, Cu, Pb, and Zn uptake by larvae of Tenebrio molitor. Metal accumulation was determined in 13 natural field soils, one metal-spiked field soil, four soil-sediment mixtures, and Cd- or Zn-spiked OECD artificial soil. Statistical analyses were used to investigate covariation of accumulation patterns with various soil metal pools and soil properties. Body concentrations of Cu and Zn in Zn-spiked OECD soils, field soils, and soil-sediment mixtures mostly remained constant. Considerable variation was noted for all Cd and Pb steady-state body concentrations among field soils and soil-sediment mixtures. For the spiked field soil and in the Cd-spiked OECD soil, body concentrations increased almost linearly with time. For the nonessential metals Cd and Pb, larval body concentrations correlated mainly to the total metal pool of the soil. Cd uptake at similar total Cd concentrations was within the same range among spiked OECD soils, field soils, and mixtures. A comparison of the findings with studies on other soil-inhabiting species shows that metal uptake patterns depend on metal type, soil type, and exposed species. It is suggested that soil organisms can be categorized according to gross divergence in ecophysiological characteristics, determined by, for instance, (non)permeability of the outer integument. These characteristics appear as similarities among multivariate functions as derived for the beetle.

  4. Partition characteristics of polycyclic aromatic hydrocarbons on soils and sediments

    USGS Publications Warehouse

    Chiou, C.T.; Mcgroddy, S.E.; Kile, D.E.

    1998-01-01

    The partition behavior was determined for three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, and pyrene, from water to a range of soil and sediment samples. The measured partition coefficients of the individual PAHs between soil/sediment organic matter (SOM) and water (i.e., K(oc) values) are relatively invariant either for the 'clean' (uncontaminated) soils or for the clean sediments; however, the mean K(oc) values on the sediments are about twice the values on the soils. This disparity is similar to the earlier observation for other nonpolar solutes and reflects the compositional differences between soil and sediment organic matters. No significant differences in K(oc) are observed between a clean coastal marine sediment and freshwater sediments. The coastal sediments that are significantly impacted by organic contaminants exhibit higher K(oc) values. At given K(ow) values (octanol-water), the PAHs exhibit much higher K(oc) values than other relatively nonpolar solutes (e.g., chlorinated hydrocarbons). This effect is shown to result from the enhanced partition of PAHs to SOM rather than from lower K(ow) values of PAHs at given supercooled liquid solute solubilities in water. The enhanced partition of PAHs over other nonpolar solutes in SOM provides an account of the markedly different correlations between log K(oc) and log K(ow) for PAHs and for other nonpolar solutes. The improved partition of PAHs in SOM stems apparently from the enhanced compatibility of their cohesive energy densities with those of the aromatic components in SOM. The approximate aromatic fraction in soil/sediment organic matter has been assessed by solid-state 13C-NMR spectroscopy.The partition behavior was determined for three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, and pyrene, from water to a range of soil and sediment samples. The measured partition coefficients of the individual PAHs between soil/sediment organic matter (SOM

  5. Geochemical characterization of seaplane lagoon sediments, Alameda Naval Air Station

    SciTech Connect

    Bono, A; Carroll, S; Esser, B; Luther, G W; O'Day, P; Randall, S

    1999-08-16

    Our objective in the characterization of sediments from Seaplane Lagoon at the Alameda Naval Air Station (NAS) was to determine the geochemical interactions that control the partitioning of cadmium, chromium, cobalt, copper, lead, mercury, nickel, and zinc between the sediments and the porewaters. Our approach was to collect several cores at the east outfall location of the Seaplane Lagoon. We determined the porewater chemistry by (1) making in situ micro-electrode measurements, (2) extracting porewaters, and (3) modeling geochemical reactions. We determined the sediment chemistry by measuring (1) elemental abundance, (2) mineralogy, and (3) trace-element speciation. This information should help the US Navy determine the long-term hazard of the sediments if they are left in place and the short-term hazard if they are dredged. We did not fully examine the geochemistry of sediments from the West Beach Landfill Wetlands site, because these sediments were distinct from the Seaplane Lagoon sediments. Our initial motivation for studying the Landfill Wetlands site was to determine the trace-element geochemistry in Seaplane Lagoon sediments that had been dredged and then disposed in the Landfill Wetlands. Unfortunately, the location of these dredged sediments is unknown. The cores we sampled were not from the Seaplane Lagoon.

  6. Arsenic chemistry in soils and sediments

    SciTech Connect

    Fendorf, S.; Nico, P.; Kocar, B.D.; Masue, Y.; Tufano, K.J.

    2009-10-15

    Arsenic is a naturally occurring trace element that poses a threat to human and ecosystem health, particularly when incorporated into food or water supplies. The greatest risk imposed by arsenic to human health results from contamination of drinking water, for which the World Health Organization recommends a maximum limit of 10 {micro}g L{sup -1}. Continued ingestion of drinking water having hazardous levels of arsenic can lead to arsenicosis and cancers of the bladder, skin, lungs and kidneys. Unfortunately, arsenic tainted drinking waters are a global threat and presently having a devastating impact on human health within Asia. Nearly 100 million people, for example, are presently consuming drinking water having arsenic concentrations exceeding the World Health Organization's recommended limit (Ahmed et al., 2006). Arsenic contamination of the environment often results from human activities such as mining or pesticide application, but recently natural sources of arsenic have demonstrated a devastating impact on water quality. Arsenic becomes problematic from a health perspective principally when it partitions into the aqueous rather than the solid phase. Dissolved concentrations, and the resulting mobility, of arsenic within soils and sediments are the combined result of biogeochemical processes linked to hydrologic factors. Processes favoring the partitioning of As into the aqueous phase, potentially leading to hazardous concentrations, vary extensively but can broadly be grouped into four categories: (1) ion displacement, (2) desorption (or limited sorption) at pH values > 8.5, (3) reduction of arsenate to arsenite, and (4) mineral dissolution, particularly reductive dissolution of Fe and Mn (hydr)oxides. Although various processes may liberate arsenic from solids, a transition from aerobic to anaerobic conditions, and commensurate arsenic and iron/manganese reduction, appears to be a dominant, but not exclusive, means by which high concentrations of dissolved

  7. How Soil Roughness Affects Runoff and Sediment Production?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of soil surface roughness on runoff and sediment production have not been clearly quantified, mostly due to the lack of a logical separation between geometric (i.e., surface microtopography) and process (i.e., runoff generation, soil detachment by raindrop and runoff) scales. In this resea...

  8. Retention and Migration of Chlorpyrifos in Aquatic Sediments and Soils

    NASA Astrophysics Data System (ADS)

    Gebremariam, S. Y.; Beutel, M.; Yonge, D.; Flury, M.; Harsh, J. B.

    2010-12-01

    The accurate description of the fate and transport of potentially toxic agricultural pesticides in sediments and soils is of great interest to environmental scientists and regulators. Of particular concern is the widely documented detection of agricultural pesticides and their byproducts in drinking water wells. This presentation discusses results of a study of the fate and transport of chlorpyrifos, a strongly hydrophobic organophosphate-pesticide, in sediments and soils collected from a range of aquatic environments. Using radio-labeled chlorpyrifos, this study is unique in its comprehensive nature and focus on aquatic sediments, for which studies involving pesticide fate and transport are limited. Study components include: (1) batch equilibrium experiments to evaluate sorption/desorption parameters; (2) kinetic and non-equilibrium sorption experiments using miniaturized flow-cells; (3) column experiments to understand patterns of pesticide break through; and (4) numerical modeling of chlorpyrifos transport through aquatic sediments and soils. Initial results show that chlorpyrifos sorption, when corrected for reversible sorption to container walls, exhibited two component sorption, a large irreversible fraction and a smaller reversible fraction that can act as a secondary source. In addition, of a wide range of soil parameters measured, organic carbon content exhibited the highest correlation with chlorpyrifos retention in cranberry field soils. Simulation models developed in this study, which account for hysteretic and nonlinear sorption, will help to better predict the fate of chlorpyrifos and other hydrophobic chemicals in sediments and soils.

  9. Urban soil moisture affecting local air temperature

    NASA Astrophysics Data System (ADS)

    Wiesner, Sarah; Ament, Felix; Eschenbach, Annette

    2015-04-01

    of urban land use is not found to be definite. Air temperature (Ta) anomalies of the suburban sites from the inner city site are analysed for several periods and seasons. During daytime a significant annual mean deviation is observed above unsealed, vegetated surfaces from a sealed site during selected relevant days. Remarkably, about a fifth of the variance of the diurnal Ta span, i.e. increase of Ta during the day, is found to be explained by normalized Θ for selected meteorological situations. In this contribution this observed relation between topsoil moisture and air temperature increase during daytime at suburban sites will be presented after describing the local conditions and soil hydrological heterogeneities at the observed urban sites.

  10. Soils as Sediment database: closing a gap between soil science and geomorphology

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2016-04-01

    Soils are an interface between the Earth's spheres and shaped by the nature of the interaction between them. The relevance of soil properties for the nature of the interaction between atmosphere, hydrosphere and biosphere is well-studied and accepted, on point- or ecotone-scale. However, this understanding of the largely vertical connections between spheres is not matched by a similar recognition of soil properties affecting processes acting largely in a lateral way across the land surface, such as erosion, transport and deposition of soil. Key areas where such an understanding is essential are all issues related to the lateral movement of soil-bound substances that affect the nature of soils itself, as well as water or vegetation downslope from the source area. The redistribution of eroded soil falls several disciplines, most notably soil science, agronomy, hydrology and geomorphology. Accordingly, the way sediment is described differs: in soil science, aggregation and structure are essential properties, while most process-based soil erosion models treat soil as a mixture of individual mineral grains, based on concepts derived in fluvial geomorphology or civil engineering. The actual behavior of aggregated sediment is not reflected by either approach and difficult to capture due to the dynamic nature of aggregation, especially in an environment such as running water. Still, a proxy to assess the uncertainties introduced by aggregation on the behavior of soil as sediment would represent a step forward. To develop such a proxy, a database collating relevant soil and sediment properties could serve as an initial step to identify which soil types and erosion scenarios are prone to generate a high uncertainty compared to the use of soil texture in erosion models. Furthermore, it could serve to develop standardized analytical procedures for appropriate description of soil as sediment.

  11. Char BC amendments for soil and sediment amelioration: BC quantification and field pilot trials

    NASA Astrophysics Data System (ADS)

    Cornelissen, G.; Braendli, R. C.; Eek, E.; Henriksen, T.; Hartnik, T.; Breedveld, G. D.

    2008-12-01

    sediment by bioturbation), chemical monitoring (porewater concentrations, diffusive transport to water and air) and biological monitoring (biodiversity, bioaccumulation). The first results indicate that i) bioturbation mixes BC into the top 5 cm of the sediments, ii) 6 months after BC amendment, PAH leaching from soils is reduced by a factor of 2, iii) Hg leaching from sediments is reduced, iv) diffusive transport from sediment to water is reduced, and v) sediment biodiversity remains unaffected by the placement of a thin BC layer.

  12. Linking soil and sediment properties for research on biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2013-04-01

    Conventional perspectives on soil erosion include the on-site damage to soil and reductions in crop yield, as well as the resulting off-site effects on water quality, runoff and sediment loads in rivers. Our evolving understanding of the Earth System has added a new dimension to the role of soil erosion within the global geochemical cycles. First, the relevance of soil as a nutrient and Carbon (C) pool was recognized. Initially, the role of soils in the global C cycle was largely considered to be limited to a vertical exchange of greenhouse house gases (GHG) between vegetation, soil and atmosphere and thus mostly studied by soil scientists, plant ecologists and climatologists. Even Critical Zone research focused mostly on weathering and regolith properties and ignored lateral fluxes of dissolved or particulate organic matter. Since the late 1990s, a wider role of soils in biogeochemical cycles has emerged. Recent estimates place the lateral movement of C between soil and sediment pools in terrestrial ecosystems (including rivers and lakes) at approximately 0.6 to 1.5 Gt per year. Some of the eroded C is replaced by photosynthesis from the atmosphere, but at a cost of additional emissions, for example due to fertilizer production. The long-term fate of the eroded and deposited soil organic matter is subject to an open debate and suffers from a lack of reliable spatial information on lateral C fluxes and its subsequent fate in terrestrial ecosystems. The connection between soil C pool, GHG emissions and erosion illustrates the relevance of surface processes for the C fluxes between Earth's spheres. Accordingly, soil is now considered as mobile system to make accurate predictions about the consequences of global change for terrestrial biogeochemical cycles and climate feedbacks. This expanded perspective on soils as dynamic pool of weathering regolith, sediment, nutrients and C at the interface between the geospheres requires the analysis of relevant soil properties

  13. Linking Soil and Sediment Properties for research on Biogeochemical Cycles

    NASA Astrophysics Data System (ADS)

    Kuhn, N. J.

    2012-04-01

    Conventional perspectives on soil erosion include the on-site damage to soil and reductions in crop yield, as well as the resulting off-site effects on water quality, runoff and sediment loads in rivers. Our evolving understanding of the Earth System has added a new dimension to the role of soil erosion within the global geochemical cycles. First, the relevance of soil as a nutrient and Carbon (C) pool was recognized. Initially, the role of soils in the global C cycle was largely considered to be limited to a vertical exchange of greenhouse house gases (GHG) between vegetation, soil and atmosphere and thus mostly studied by soil scientists, plant ecologists and climatologists. Even Critical Zone research focused mostly on weathering and regolith properties and ignored lateral fluxes of dissolved or particulate organic matter. Since the late 1990s, a wider role of soils in biogeochemical cycles has emerged. Recent estimates place the lateral movement of C between soil and sediment pools in terrestrial ecosystems (including rivers and lakes) at approximately 0.6 to 1.5 Gt per year. Some of the eroded C is replaced by photosynthesis from the atmosphere, but at a cost of additional emissions, for example due to fertilizer production. The long-term fate of the eroded and deposited soil organic matter is subject to an open debate and suffers from a lack of reliable spatial information on lateral C fluxes and its subsequent fate in terrestrial ecosystems. The connection between soil C pool, GHG emissions and erosion illustrates the relevance of surface processes for the C fluxes between Earth's spheres. Accordingly, soil is now considered as mobile system to make accurate predictions about the consequences of global change for terrestrial biogeochemical cycles and climate feedbacks. This expanded perspective on soils as dynamic pool of weathering regolith, sediment, nutrients and C at the interface between the geospheres requires the analysis of relevant soil properties

  14. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Agricultural and Food Chemistry, 23:720-724 (1975). (2) Goring, C.A.I., Hamaker, J.W., (eds). Organic Chemicals... minerals and the amount present in a sediment or soil. (iii) “Organic matter” is the organic fraction of.... (vii) “Sediment” is the unconsolidated inorganic and organic material that is suspended in and...

  15. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Agricultural and Food Chemistry, 23:720-724 (1975). (2) Goring, C.A.I., Hamaker, J.W., (eds). Organic Chemicals... minerals and the amount present in a sediment or soil. (iii) “Organic matter” is the organic fraction of.... (vii) “Sediment” is the unconsolidated inorganic and organic material that is suspended in and...

  16. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Agricultural and Food Chemistry, 23:720-724 (1975). (2) Goring, C.A.I., Hamaker, J.W., (eds). Organic Chemicals... minerals and the amount present in a sediment or soil. (iii) “Organic matter” is the organic fraction of.... (vii) “Sediment” is the unconsolidated inorganic and organic material that is suspended in and...

  17. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Agricultural and Food Chemistry, 23:720-724 (1975). (2) Goring, C.A.I., Hamaker, J.W., (eds). Organic Chemicals... minerals and the amount present in a sediment or soil. (iii) “Organic matter” is the organic fraction of.... (vii) “Sediment” is the unconsolidated inorganic and organic material that is suspended in and...

  18. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Agricultural and Food Chemistry, 23:720-724 (1975). (2) Goring, C.A.I., Hamaker, J.W., (eds). Organic Chemicals... minerals and the amount present in a sediment or soil. (iii) “Organic matter” is the organic fraction of.... (vii) “Sediment” is the unconsolidated inorganic and organic material that is suspended in and...

  19. Can control of soil erosion mitigate water pollution by sediments?

    PubMed

    Rickson, R J

    2014-01-15

    The detrimental impact of sediment and associated pollutants on water quality is widely acknowledged, with many watercourses in the UK failing to meet the standard of 'good ecological status'. Catchment sediment budgets show that hill slope erosion processes can be significant sources of waterborne sediment, with rates of erosion likely to increase given predicted future weather patterns. However, linking on-site erosion rates with off-site impacts is complicated because of the limited data on soil erosion rates in the UK and the dynamic nature of the source-pathway-receptor continuum over space and time. Even so, soil erosion control measures are designed to reduce sediment production (source) and mobilisation/transport (pathway) on hill slopes, with consequent mitigation of pollution incidents in watercourses (receptors). The purpose of this paper is to review the scientific evidence of the effectiveness of erosion control measures used in the UK to reduce sediment loads of hill slope origin in watercourses. Although over 73 soil erosion mitigation measures have been identified from the literature, empirical data on erosion control effectiveness are limited. Baseline comparisons for the 18 measures where data do exist reveal erosion control effectiveness is highly variable over time and between study locations. Given the limitations of the evidence base in terms of geographical coverage and duration of monitoring, performance of the different measures cannot be extrapolated to other areas. This uncertainty in effectiveness has implications for implementing erosion/sediment risk reduction policies, where quantified targets are stipulated, as is the case in the EU Freshwater Fish and draft Soil Framework Directives. Also, demonstrating technical effectiveness of erosion control measures alone will not encourage uptake by land managers: quantifying the costs and benefits of adopting erosion mitigation is equally important, but these are uncertain and difficult to

  20. Can control of soil erosion mitigate water pollution by sediments?

    PubMed

    Rickson, R J

    2014-01-15

    The detrimental impact of sediment and associated pollutants on water quality is widely acknowledged, with many watercourses in the UK failing to meet the standard of 'good ecological status'. Catchment sediment budgets show that hill slope erosion processes can be significant sources of waterborne sediment, with rates of erosion likely to increase given predicted future weather patterns. However, linking on-site erosion rates with off-site impacts is complicated because of the limited data on soil erosion rates in the UK and the dynamic nature of the source-pathway-receptor continuum over space and time. Even so, soil erosion control measures are designed to reduce sediment production (source) and mobilisation/transport (pathway) on hill slopes, with consequent mitigation of pollution incidents in watercourses (receptors). The purpose of this paper is to review the scientific evidence of the effectiveness of erosion control measures used in the UK to reduce sediment loads of hill slope origin in watercourses. Although over 73 soil erosion mitigation measures have been identified from the literature, empirical data on erosion control effectiveness are limited. Baseline comparisons for the 18 measures where data do exist reveal erosion control effectiveness is highly variable over time and between study locations. Given the limitations of the evidence base in terms of geographical coverage and duration of monitoring, performance of the different measures cannot be extrapolated to other areas. This uncertainty in effectiveness has implications for implementing erosion/sediment risk reduction policies, where quantified targets are stipulated, as is the case in the EU Freshwater Fish and draft Soil Framework Directives. Also, demonstrating technical effectiveness of erosion control measures alone will not encourage uptake by land managers: quantifying the costs and benefits of adopting erosion mitigation is equally important, but these are uncertain and difficult to

  1. Respiratory disease and particulate air pollution in Santiago Chile: contribution of erosion particles from fine sediments.

    PubMed

    Garcia-Chevesich, Pablo A; Alvarado, Sergio; Neary, Daniel G; Valdes, Rodrigo; Valdes, Juan; Aguirre, Juan José; Mena, Marcelo; Pizarro, Roberto; Jofré, Paola; Vera, Mauricio; Olivares, Claudio

    2014-04-01

    Air pollution in Santiago is a serious problem every winter, causing thousands of cases of breathing problems within the population. With more than 6 million people and almost two million vehicles, this large city receives rainfall only during winters. Depending on the frequency of storms, statistics show that every time it rains, air quality improves for a couple of days, followed by extreme levels of air pollution. Current regulations focus mostly on PM10 and PM2.5, due to its strong influence on respiratory diseases. Though more than 50% of the ambient PM10s in Santiago is represented by soil particles, most of the efforts have been focused on the remaining 50%, i.e. particulate material originating from fossil and wood fuel combustion, among others. This document emphasizes the need for the creation of erosion/sediment control regulations in Chile, to decrease respiratory diseases on Chilean polluted cities.

  2. Respiratory disease and particulate air pollution in Santiago Chile: contribution of erosion particles from fine sediments.

    PubMed

    Garcia-Chevesich, Pablo A; Alvarado, Sergio; Neary, Daniel G; Valdes, Rodrigo; Valdes, Juan; Aguirre, Juan José; Mena, Marcelo; Pizarro, Roberto; Jofré, Paola; Vera, Mauricio; Olivares, Claudio

    2014-04-01

    Air pollution in Santiago is a serious problem every winter, causing thousands of cases of breathing problems within the population. With more than 6 million people and almost two million vehicles, this large city receives rainfall only during winters. Depending on the frequency of storms, statistics show that every time it rains, air quality improves for a couple of days, followed by extreme levels of air pollution. Current regulations focus mostly on PM10 and PM2.5, due to its strong influence on respiratory diseases. Though more than 50% of the ambient PM10s in Santiago is represented by soil particles, most of the efforts have been focused on the remaining 50%, i.e. particulate material originating from fossil and wood fuel combustion, among others. This document emphasizes the need for the creation of erosion/sediment control regulations in Chile, to decrease respiratory diseases on Chilean polluted cities. PMID:24485904

  3. Searsville Sediment Experiment: What is the ideal agricultural soil?

    NASA Astrophysics Data System (ADS)

    Leal, J.; Lo, D.; Patel, N.; Gu, S.

    2014-12-01

    The purpose of this experiment is to decide whether or not the sediment located within Searsville Dam at the Jasper Ridge Biological Preserve is well suited for agricultural soil. By utilizing various combinations of sediment, farm soil, compost, and horse manure to grow basil plants, we underwent an exploratory study in order to better understand what type of materials and nutrients plants can best thrive within. Our general experiment protocol includes watering the crops with irrigation every day while young, and then limiting that water exposure to only Mondays, Wednesdays, and Fridays as they become more established. The basil is growing in pots filled with the different amounts of material, and are arranged randomly to prevent certain plants from getting more sunlight than others. The whole experiment plot is covered with a thin white fabric and secured with bricks and wood to keep out pests in the garden. In order to observe trends in the basil development, plant height and leaf number is recorded once every week. During the third week of the study we performed soil texture tests, and within the fourth week we calculated pH data. We discovered that the sediment our project focuses upon is 10-18% clay and 50% sand which categorizes it as loam, and the Stanford farm soil that serves as our control group contains 20-26% clay and 30% sand so it is a silt loam material. The pH tests also showed an average of 7.45 for sediment, 7.3 for farm soil, 7.85 for compost, and 7.65 for horse manure. By looking at all of the data recorded over the five-week time period, we have so far noticed that the 50% sediment and 50% horse manure combination consistently has the best height increase as well as leaf size and content. The 50% sediment and 50% compost mixture has also performed well in those terms, and is therefore a possibility for the best agricultural soil. However, future lab work conducted by Stanford students to examine the nutrient content of the basil tissue, along

  4. Nitrogen release from forest soils containing sulfide-bearing sediments

    NASA Astrophysics Data System (ADS)

    Maileena Nieminen, Tiina; Merilä, Päivi; Ukonmaanaho, Liisa

    2014-05-01

    Soils containing sediments dominated by metal sulfides cause high acidity and release of heavy metals, when excavated or drained, as the aeration of these sediments causes formation of sulfuric acid. Consequent leaching of acidity and heavy metals can kill tree seedlings and animals such as fish, contaminate water, and corrode concrete and steel. These types of soils are called acid sulfate soils. Their metamorphic equivalents, such as sulfide rich black shales, pose a very similar risk of acidity and metal release to the environment. Until today the main focus in treatment of the acid sulfate soils has been to prevent acidification and metal toxicity to agricultural crop plants, and only limited attention has been paid to the environmental threat caused by the release of acidity and heavy metals to the surrounding water courses. Even less attention is paid on release of major nutrients, such as nitrogen, although these sediments are extremely rich in carbon and nitrogen and present a potentially high microbiological activity. In Europe, the largest cover of acid sulfate soils is found in coastal lowlands of Finland. Estimates of acid sulfate soils in agricultural use range from 1 300 to 3 000 km2, but the area in other land use classes, such as managed peatland forests, is presumably larger. In Finland, 49 500 km2 of peatlands have been drained for forestry, and most of these peatland forests will be at the regeneration stage within 10 to 30 years. As ditch network maintenance is often a prerequisite for a successful establishment of the following tree generation, the effects of maintenance operations on the quality of drainage water should be under special control in peatlands underlain by sulfide-bearing sediments. Therefore, identification of risk areas and effective prevention of acidity and metal release during drain maintenance related soil excavating are great challenges for forestry on coastal lowlands of Finland. The organic and inorganic nitrogen

  5. Relative air permeability as function of saturation in soil venting

    SciTech Connect

    Stylianou, C.; DeVantier, B.A.

    1995-04-01

    Traditionally, soil remediation involved soil flushing, or excavation followed by landfilling or treatment. In recent years, recognizing the major environmental problem of soil contamination by VOCs, soil vapor extraction (SVE, also known as soil venting) has been applied as a form of in situ remediation. A key parameter in modeling soil-venting systems is relative air permeability, determined as a function of liquid saturation. The focus of the present study was to characterize the relationship of the relative air permeability as a function of air saturation in soil-venting systems. A new laboratory apparatus was used to simulate the soil venting and measure the air permeability of soil samples. Sand samples wetted with mixtures of water and gasoline at different ratios were used. It was revealed that the prediction of relative air permeability for moist noncohesive soil can be made in terms of intrinsic permeability and air-filled porosity alone, and not the type of liquid present in the pores. Comparisons of measured data with existing relations for relative air permeability as a function of total liquid saturation were made to determine the most accurate and practical forms for engineering applications. For the sand sample used, the evaluation revealed that compared to the existing relations, a derived second-order polynomial expression provides a good estimate of relative air permeability and does not require estimation of soil-water-retention curve parameters.

  6. A regional soil and sediment geochemical study in northern California

    USGS Publications Warehouse

    Goldhaber, M.B.; Morrison, J.M.; Holloway, J.M.; Wanty, R.B.; Helsel, D.R.; Smith, D.B.

    2009-01-01

    Regional-scale variations in soil geochemistry were investigated in a 20,000-km2 study area in northern California that includes the western slope of the Sierra Nevada, the southern Sacramento Valley and the northern Coast Ranges. Over 1300 archival soil samples collected from the late 1970s to 1980 in El Dorado, Placer, Sutter, Sacramento, Yolo and Solano counties were analyzed for 42 elements by inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry following a near-total dissolution. These data were supplemented by analysis of more than 500 stream-sediment samples from higher elevations in the Sierra Nevada from the same study site. The relatively high-density data (1 sample per 15 km2 for much of the study area) allows the delineation of regional geochemical patterns and the identification of processes that produced these patterns. The geochemical results segregate broadly into distinct element groupings whose distribution reflects the interplay of geologic, hydrologic, geomorphic and anthropogenic factors. One such group includes elements associated with mafic and ultramafic rocks including Cr, Ni, V, Co, Cu and Mg. Using Cr as an example, elevated concentrations occur in soils overlying ultramafic rocks in the foothills of the Sierra Nevada (median Cr = 160 mg/kg) as well as in the northern Coast Ranges. Low concentrations of these elements occur in soils located further upslope in the Sierra Nevada overlying Tertiary volcanic, metasedimentary and plutonic rocks (granodiorite and diorite). Eastern Sacramento Valley soil samples, defined as those located east of the Sacramento River, are lower in Cr (median Cr = 84 mg/kg), and are systematically lower in this suite compared to soils from the west side of the Sacramento Valley (median Cr = 130 mg/kg). A second group of elements showing a coherent pattern, including Ca, K, Sr and REE, is derived from relatively silicic rocks types. This group occurs at elevated

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

    SciTech Connect

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

    2004-05-25

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

  8. Assessing the environmental availability of uranium in soils and sediments

    SciTech Connect

    Amonette, J.E.; Holdren, G.R. Jr.; Krupa, K.M.; Lindenmeier, C.W.

    1994-06-01

    Soils and sediments contaminated with uranium pose certain environmental and ecological risks. At low to moderate levels of contamination, the magnitude of these risks depends not only on the absolute concentrations of uranium in the material but also on the availability of the uranium to drinking water supplies, plants, or higher organisms. Rational approaches for regulating the clean-up of sites contaminated with uranium, therefore, should consider the value of assessing the environmental availability of uranium at the site before making decisions regarding remediation. The purpose of this work is to review existing approaches and procedures to determine their potential applicability for assessing the environmental availability of uranium in bulk soils or sediments. In addition to making the recommendations regarding methodology, the authors have tabulated data from the literature on the aqueous complexes of uranium and major uranium minerals, examined the possibility of predicting environmental availability of uranium based on thermodynamic solubility data, and compiled a representative list of analytical laboratories capable of performing environmental analyses of uranium in soils and sediments.

  9. Remediation of contaminated soils and sediments using Daramend bioremediation

    SciTech Connect

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

    1996-05-01

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

  10. Analysis of chlorothalonil and three degradates in sediment and soil

    USGS Publications Warehouse

    Hladik, M.L.; Kuivila, K.M.

    2008-01-01

    A method has been developed for the simultaneous extraction of chlorothalonil and three of its degradates (4-hydroxy-2,5,6- trichloroisophthalonitrile, 1-carbamoyl-3-cyano-4-hydroxy-2,5,6- trichlorobenzene, and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene) from soils and sediments; the compounds were extracted using sonication with acetone and isolation of the parent compound and matrix interferences from the degradates by solid phase extraction (SPE). The chlorothalonil fraction underwent further coextracted matrix interference removal with Florisil. The degradates were derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). All compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Recoveries on a spiked (20 and 200 ??g kg-1) sediment ranged from 80% to 91% with calculated limits of detection of 1-5 ??g kg-1 dry weight sediment. An additional 20 sediment samples were collected in watersheds from the Southeastern United States where chlorothalonil is used widely on peanuts and other crops. None of the target compounds were detected. Laboratory fortified recoveries of chlorothalonil and its degradates in these environmental sediment samples ranged from 75% to 89%.

  11. Modelling evolution of air dose rates in river basins in Fukushima Prefecture affected by sediment-sorbed radiocesium redistribution

    NASA Astrophysics Data System (ADS)

    Malins, A.; Sakuma, K.; Nakanishi, T.; Kurikami, H.; Machida, M.; Kitamura, A.; Yamada, S.

    2015-12-01

    The radioactive 134Cs and 137Cs isotopes deposited over Fukushima Prefecture by the Fukushima Daiichi nuclear disaster are the predominant radiological concern for the years following the accident. This is because the energetic gamma radiation they emit on decay constitutes the majority of the elevated air dose rates that now afflict the region. Therefore, we developed a tool for calculating air dose rates from arbitrary radiocesium spatial distributions across the land surface and depth profiles within the ground. As cesium is strongly absorbed by clay soils, its primary redistribution mechanism within Fukushima Prefecture is by soil erosion and water-borne sediment transport. Each year between 0.1~1% of the total radiocesium inventory in the river basins neighboring Fukushima Daiichi is eroded from the land surface and enters into water courses, predominantly during typhoon storms. Although this is a small amount in relative terms, in absolute terms it corresponds to terabecquerels of 134Cs and 137Cs redistribution each year and this can affect the air dose rate at locations of high erosion and sediment deposition. This study inputs the results of sediment redistribution simulations into the dose rate evaluation tool to calculate the locations and magnitude of air dose rate changes due to radiocesium redistribution. The dose rate calculations are supported by handheld survey instrument results taken within the Prefecture.

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

    EPA Science Inventory

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

  13. Ammonia- and methane-oxidizing microorganisms in high-altitude wetland sediments and adjacent agricultural soils.

    PubMed

    Yang, Yuyin; Shan, Jingwen; Zhang, Jingxu; Zhang, Xiaoling; Xie, Shuguang; Liu, Yong

    2014-12-01

    Ammonia oxidation is known to be carried out by ammonia-oxidizing bacteria (AOB) and archaea (AOA), while methanotrophs (methane-oxidizing bacteria (MOB)) play an important role in mitigating methane emissions from the environment. However, the difference of AOA, AOB, and MOB distribution in wetland sediment and adjacent upland soil remains unclear. The present study investigated the abundances and community structures of AOA, AOB, and MOB in sediments of a high-altitude freshwater wetland in Yunnan Province (China) and adjacent agricultural soils. Variations of AOA, AOB, and MOB community sizes and structures were found in water lily-vegetated and Acorus calamus-vegetated sediments and agricultural soils (unflooded rice soil, cabbage soil, and garlic soil and flooded rice soil). AOB community size was higher than AOA in agricultural soils and lily-vegetated sediment, but lower in A. calamus-vegetated sediment. MOB showed a much higher abundance than AOA and AOB. Flooded rice soil had the largest AOA, AOB, and MOB community sizes. Principal coordinate analyses and Jackknife Environment Clusters analyses suggested that unflooded and flooded rice soils had relatively similar AOA, AOB, and MOB structures. Cabbage soil and A. calamus-vegetated sediment had relatively similar AOA and AOB structures, but their MOB structures showed a large difference. Nitrososphaera-like microorganisms were the predominant AOA species in garlic soil but were present with a low abundance in unflooded rice soil and cabbage soil. Nitrosospira-like AOB were dominant in wetland sediments and agricultural soils. Type I MOB Methylocaldum and type II MOB Methylocystis were dominant in wetland sediments and agricultural soils. Moreover, Pearson's correlation analysis indicated that AOA Shannon diversity was positively correlated with the ratio of organic carbon to nitrogen (p < 0.05). This work could provide some new insights toward ammonia and methane oxidation in soil and wetland sediment

  14. Extraction of arsenate and arsenite species from soils and sediments

    PubMed Central

    Georgiadis, Myron; Cai, Yong; Solo-Gabriele, Helena M.

    2008-01-01

    The primary objective of this study was to develop a simple method that can be used to extract the more readily mobilizable and bioavailable arsenic species from soil and sediment while at the same time minimizing the transformation between (AsIII) and (AsV), the two most commonly found arsenic species in the environment. Several extraction strategies were evaluated using phosphate as extractant in combination with either ethylenediaminetetraacetic acid (EDTA), hydroxylamine hydrochloride (NH2OH·HCl), or sodium diethyldithiocarbamate trihydrate (NaDDC).The addition of EDTA in the phosphate solution did not prevent AsIII from oxidation. While promising results were shown when 1% NH2OH·HCl was added, conversion of AsIII began to occur with extended extraction time (>12 h). Good results were achieved using 10 mM phosphate and 0.5% NaDDC where AsIII oxidation was clearly minimized. The combined phosphate and NaDDC solution was applied to several soil and sediment samples. AsIII spiked was quantitatively recovered in all soil types tested. PMID:16198465

  15. Plutonium mobility studies in soil sediment decontaminated by means of a soil-washing technology

    SciTech Connect

    Negri, M.C.; Orlandini, K.A.; Swift, N.; Carfagno, D.

    1995-07-01

    The ACT*DE*CON{sup SM} process extracts plutonium from contaminated soils/sediments by means of a series of washings with a blend of chemicals, that includes a chelating agent, an oxidant, and carbonates. At the end of the process, the Pu level in the soil is lowered to 25-30 pCi/g from an initial contamination level averaging 500 pCi/g. The radionuclide still present in the soil at the end of the treatment must be strongly immobilized in or onto the soil particles to minimize the risk of its percolation to the aquifer and/or uptake by vegetation. This paper reports the investigation of residual Pu mobility as K{sub d} (distribution coefficient) in the treated soil/sediment. Six batches of contaminated soil were treated simultaneously by means of the ACT*DE*CON{sup SM} process. Some batches of the treated soil were amended with a standard fertilizer treatment of compost and nutrient and brought to pH 8.5. The treated soil, treated and fertilized soil, and the untreated controls were then incubated at 18{degrees}C for 90 days. At four different times, a small aliquot of soil was retrieved from each of the batches and contacted with rainwater for six days to determine the Pu solid/liquid distribution and K{sub d}. Results indicated that a higher total amount of Pu was leached from the untreated soil, probably as a consequence of the higher content of available/exchangeable Pu in this soil compared with the treated ones. Treated/fertilized soils showed Pu leaching at intermediate levels between those for treated and untreated soils, at least for the first 30 days of incubation. K{sub d} values at the beginning of the incubation period were significantly lower in the untreated and treated/fertilized soils compared with those for the treated-only, but at 90 days, these values were substantially equal among the three different soils. Traces of the chelant were detectable only in treated, unfertilized soil.

  16. Partition of nonpolar organic pollutants from water to soil and sediment organic matters

    USGS Publications Warehouse

    Chiou, C.T.

    1995-01-01

    The partition coefficients (Koc) of carbon tetrachloride and 1,2-dichlorobenzene between normal soil/sediment organic matter and water have been determined for a large set of soils, bed sediments, and suspended solids from the United States and the People's Republic of China. The Koc values for both solutes are quite invariant either for the soils or for the bed sediments; the values on bed sediments are about twice those on soils. The similarity of Koc values between normal soils and between normal bed sediments suggests that natural organic matters in soils (or sediments) of different geographic origins exhibit comparable polarities and possibly comparable compositions. The results also suggest that the process that converts eroded soils into bed sediments brings about a change in the organic matter property. The difference between soil and sediment Koc values provides a basis for identifying the source of suspended solids in river waters. The very high Koc values observed for some special soils and sediments are diagnostic of severe anthropogenic contamination.

  17. Interdisciplinary Intercomparison of Black Carbon Analysis in Soil and Sediment

    NASA Astrophysics Data System (ADS)

    Schmidt, Michael W. I.; Masiello, Caroline A.

    2007-08-01

    Analysis and Characterization of Black Carbon in the Environment, Vienna, Austria, 18-19 April 2007 Last April, a symposium was held to discuss new aspects of the rapidly growing field of research focusing on black carbon in soil, sediment, and the atmosphere. About 70 scientists attended the 2-day session during the European Geosciences Union General Assembly, in Vienna. Part of this symposium included a workshop on chemical reference materials, where results of an interdisciplinary intercomparison of black carbon (BC) measurements in different environmental matrices were released.

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

    PubMed

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

    2014-12-01

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

  19. Pesticides in western Canadian mountain air and soil.

    PubMed

    Daly, Gillian L; Lei, Ying D; Teixeira, Camilla; Muir, Derek C G; Wania, Frank

    2007-09-01

    The distribution of organochlorine pesticides (OCP; in past and current use) in the mountains of western Canada was determined by sampling air, soil, and lichen along three elevational transects in 2003-2004. Two transects west of the Continental Divide were located in Mount Revelstoke and Yoho National Park, while the Observation Peak transect in Banff National Park is east of the divide. XAD-based passive air samplers, yielding annually averaged air concentrations, were deployed, and soils were collected at all 22 sampling sites, whereas lichen were only sampled in Revelstoke. Back trajectory analysis showed limited air mass transport from the Prairies to the east, but a high frequency of air arriving from the southwest, which includes agricultural regions in British Columbia and Washington State. Endosulfan, dieldrin, and a-hexachlorocyclohexane were the most prevalent OCPs in air and soil; hexachlorobenzene was only abundant in air; chlorothalonil, dacthal, and pentachloronitrobenzene were also consistently present. OCP air concentrations were similar across the three transects, suggesting efficient atmospheric mixing on a local and regional scale. Soil concentrations and soil/air concentration ratios of many OCPs were significantly higher west of the Continental Divide. The soil and lichen concentrations of most OCPs increased with altitude in Revelstoke, and displayed maxima at intermediate elevations at Yoho and Observation Peak. These distribution patterns can be understood as being determined by the balance between atmospheric deposition to, and retention within, the soils. Higher deposition, due to more precipitation falling at lower temperatures, likely occurs west of the divide and at higher elevations. Higher retention, due to higher soil organic matter content, is believed to occur in soils below the tree line. Highest pesticide concentrations are thus found intemperate mountain soils that are rich in organic matter and receive large amounts of cold

  20. TECHNOLOGY ASSESSMENT OF SOIL VAPOR EXTRACTION AND AIR SPARGING

    EPA Science Inventory

    Air sparging, also called "in situ air stripping and in situ volatilization" injects air into the saturated zone to strip away volatile organic compounds (VOCs) dissolved in groundwater and adsorbed to soil. hese volatile contaminants transfer in a vapor phase to the unsaturated ...

  1. Magnetic Parameter Changes in Soil and Sediments in the Presence of Hydrocarbon Contamination

    NASA Astrophysics Data System (ADS)

    Appel, E.; Porsch, K.; Rijal, M. L.; Ameen, N. N.; Kappler, A.

    2014-12-01

    Magnetic proxies were successfully used for fast and non-destructive detection of fly ash related heavy metal pollution. Correlations of magnetic signals with organic contaminants in soils and sediments were also reported; however, their significance is unclear because of co-existing heavy metal pollution. At a hydrocarbon (HC) contaminated former military airbase (Hradcany, Czech Rep.), where heavy metal contents are insignificant, we detected clearly higher magnetic concentrations at the top of the groundwater fluctuation (GWF) zone. Frequent GWF by up to ca. one meter was caused through remediation by air sparging. In this study and all previous ones magnetite was identified as the dominant phase for higher magnetic concentrations. To determine the importance of microbial activity and soil parameters on changes in magnetic susceptibility (MS) laboratory batch experiments with different microbially active and sterile soils without carbon addition and with gasoline amendment were setup. MS of these microcosms was followed weekly. Depending on the soil MS either increased or decreased by up to ~7% and remained constant afterwards. The main findings were that MS changes were mainly microbially driven and influenced by the bioavailable Fe content, the initial MS and the organic carbon content of the soils. Moreover, we tested magnetic changes in laboratory columns, filled with sand from the field site Hradcany, by simulating water level changes. The observed changes were small and hardly statistically significant. Our laboratory studies revealed that different factors influence changes in magnetic properties of soil/sediments after HC contamination, with much smaller effects than expected from anomalies observed at field sites. With the present results, the ambitious goal of using magnetic monitoring for detecting HC contaminations by oil spills seem far from practical application.

  2. Use of the mercury record in Red Tarn sediments to reveal air pollution history and the implications of catchment erosion.

    PubMed

    Yang, Handong; Smyntek, Peter

    2014-11-01

    Red Tarn is a cirque lake with a small ratio of terrestrial area to lake area, surrounded by glacial edges with little soil in the catchment. A sediment core taken from the deepest area of the lake was (210)Pb dated and validated by (137)Cs and (241)Am stratigraphic records. The core was analysed for mercury (Hg) and other elements. The results show Hg pollution before the mid-19th century, and thereafter, a rapid increase in Hg pollution into modern time, followed by a decline in pollution since 1968-1970. This agrees well with the decline in UK Hg emissions since the Clear Air Act of 1968. The results suggest that the core has recorded Hg air pollution history, and it can be used to benchmark Hg changes in the sediments from other lakes in the region up to the late 1980s. However, increased (210)Pb fluxes after the late 1980s indicate enhanced catchment erosion, which has brought more legacy Hg in the catchment into the lake. As a consequence, since 2000, the Hg in the sediment record no longer reflects the atmospheric Hg deposition. The core shows how dominant Hg sources for the lake changed from atmospheric deposition to the catchment inputs, and demonstrates that contaminated catchment inputs have not only increased Hg fluxes to the lake sediments but have also increased Hg concentrations in the sediments.

  3. How sedge meadow soils, microtopography, and vegetation respond to sedimentation

    USGS Publications Warehouse

    Werner, K.J.; Zedler, Joy B.

    2002-01-01

    The expansion of urban and agricultural activities in watersheds of the Midwestern USA facilitates the conversion of species-rich sedge meadows to stands of Phalaris arundinacea and Typha spp. We document the role of sediment accumulation in this process based on field surveys of three sedge meadows dominated by Carex stricta, their adjacent Phalaris or Typha stands, and transitions from Carex to these invasive species. The complex microtopography of Carex tussocks facilitates the occurrence of other native species. Tussock surface area and species richness were positively correlated in two marshes (r2 = 0.57 and 0.41); on average, a 33-cm-tall tussock supported 7.6 species. Phalaris also grew in tussock form in wetter areas but did not support native species. We found an average of 10.5 Carex tussocks per 10-m transect, but only 3.5 Phalaris tussocks. Microtopographic relief, determined with a high-precision GPS, measured 11% greater in Carex meadows than Phalaris stands. Inflowing sediments reduced microtopographic variation and surface area for native species. We calculated a loss of one species per 1000 cm2 of lost tussock surface area, and loss of 1.2 species for every 10-cm addition of sediment over the sedge meadow surface. Alluvium overlying the sedge meadow soil had a smaller proportion of organic matter content and higher dry bulk density than the buried histic materials. We conclude that sedimentation contributes to the loss of native species in remnant wetlands. ?? 2002, The Society of Wetland Scientists.

  4. Pollution Studies on Soils and Stream Sediments From Argentina Using Magnetic Techniques

    NASA Astrophysics Data System (ADS)

    Sinito, A. M.

    2007-05-01

    The number of studies of contamination and magnetic proxies for environmental pollution in developed countries increased gradually since the 80s. In South American countries pollution studies are reduced in number; particularly in Argentina, studies on magnetic proxies are scarce and have been carried out since few years ago by the author and collaborators. This review deals with studies of magnetic proxies for pollution conducted in soils, lagoon and stream sediments from three districts (La Plata, Chascomús and Tandil) of the most densely populated province, Buenos Aires. Stream and lagoon sediments were studied in La Plata and Chascomús. In La Plata a higher concentration of magnetic minerals and a clear trend to finer grain size is observed in the top of the sequence of the most polluted streams. These results suggest an extra contribution of anthropogenic materials, possibly related to significant contribution of pollutants. The heavy metals concentration and some magnetic parameters show a good correlation. Longitudinal and vertical behaviour of the most polluted stream sediments was studied. According to the magnetic parameters and the content of heavy metals two distinctive groups are identified. The vertical distribution of sediments reveals a recent anthropogenic influence, possibly corresponding to the last 20-40 years. The magnetic parameters dependent on magnetic size grain and characteristics are more significant than those dependent on magnetic concentration for description of longitudinal and vertical distribution of present heavy metals. In Chascomús lagoon sediments, magnetic parameters and chemical determinations were correlated; the best results were obtained for parameters depending on magnetic characteristics, which show distinctive points and wide areas affected by pollution. This magnetic inference is supported by high contents of heavy metals, especially lead and zinc. Influence of pollution was investigated in Tandil and La Plata soils

  5. Process recognition in multi-element soil and stream-sediment geochemical data

    USGS Publications Warehouse

    Grunsky, E.C.; Drew, L.J.; Sutphin, D.M.

    2009-01-01

    Stream-sediment and soil geochemical data from the Upper and Lower Coastal Plains of South Carolina (USA) were studied to determine relationships between soils and stream sediments. From multi-element associations, characteristic compositions were determined for both media. Primary associations of elements reflect mineralogy, including heavy minerals, carbonates and clays, and the effects of groundwater. The effects of groundwater on element concentrations are more evident in soils than stream sediments. A "winnowing index" was created using ratios of Th to Al that revealed differing erosional and depositional environments. Both soils and stream sediments from the Upper and Lower Coastal Plains show derivation from similar materials and subsequent similar multi-element relationships, but have some distinct differences. In the Lower Coastal Plain, soils have high values of elements concentrated in heavy minerals (Ce, Y, Th) that grade into high values of elements concentrated into finer-grain-size, lower-density materials, primarily comprised of carbonates and feldspar minerals (Mg, Ca, Na, K, Al). These gradational trends in mineralogy and geochemistry are inferred to reflect reworking of materials during marine transgressions and regressions. Upper Coastal Plain stream-sediment geochemistry shows a higher winnowing index relative to soil geochemistry. A comparison of the 4 media (Upper Coastal Plain soils and stream sediments and Lower Coastal Plain soils and stream sediments) shows that Upper Coastal Plain stream sediments have a higher winnowing index and a higher concentration of elements contained within heavy minerals, whereas Lower Coastal Plain stream sediments show a strong correlation between elements typically contained within clays. It is not possible to calculate a functional relationship between stream sediment-soil compositions for all elements due to the complex history of weathering, deposition, reworking and re-deposition. However, depending on

  6. Soil characteristics of sediment-amended baldcypress (Taxodium distichum) swamps of coastal Louisiana

    USGS Publications Warehouse

    Jiang, Ming; Middleton, Beth A.

    2011-01-01

    Amendments of sediment from dredging activities have played an important role in raising the elevation of sinking coastal wetlands. This study compared the soil characteristics of sediment- amended coastal swamps in the Barataria Preserve unit of Jean Lafitte National Historical Park and Preserve with natural swamps along Bayou des Familles. The sandy sediment amendments used in the coastal forests had different soil texture and characteristics than the more organic soils of the natural swamps. Three years after the application of these sediments on the sediment-amended swamps, dewatering and compaction of the sediment had occurred but the sediment still had high salinity and bulk density, and low organic matter content. The two sediment-amended swamps differed from each other in that Site 1 had a higher elevation (mean = 25 cm higher) and drier soil than Site 2. The effects of sediment in coastal forested wetlands require separate consideration from studies of salt marshes, e.g., the weight of the sediment might damage tree roots, or the amendments might influence soil stability during storms in a different way. Generally, this study suggests that shallower depths of sediment are more likely to yield environments beneficial to these sinking baldcypress swamps in coastal Louisiana.

  7. Environmental monitoring of chromium in air, soil, and water.

    PubMed

    Vitale, R J; Mussoline, G R; Rinehimer, K A

    1997-08-01

    Historical uses of chromium have resulted in its widespread release into the environment. In recent years, a significant amount of research has evaluated the impact of chromium on human health and the environment. Additionally, numerous analytical methods have been developed to identify and quantitate chromium in environmental media in response to various state and federal mandates such as CERCLA, RCRA, CWA, CAA, and SWDA. Due to the significant toxicity differences between trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium, it is essential that chromium be quantified in these two distinct valence states to assess the potential risks to exposure to each in environmental media. Speciation is equally important because of their marked differences in environmental behavior. As the knowledge of risks associated with each valence state has grown and regulatory requirements have evolved, methods to accurately quantitate these species at ever-decreasing concentrations within environmental media have also evolved. This paper addresses the challenges of chromium species quantitation and some of the most relevant current methods used for environmental monitoring, including ASTM Method D5281 for air, SW-846 Methods 3060A, 7196A and 7199 for soils, sediments, and waste, and U.S. EPA Method 218.6 for water.

  8. Environmental monitoring of chromium in air, soil, and water.

    PubMed

    Vitale, R J; Mussoline, G R; Rinehimer, K A

    1997-08-01

    Historical uses of chromium have resulted in its widespread release into the environment. In recent years, a significant amount of research has evaluated the impact of chromium on human health and the environment. Additionally, numerous analytical methods have been developed to identify and quantitate chromium in environmental media in response to various state and federal mandates such as CERCLA, RCRA, CWA, CAA, and SWDA. Due to the significant toxicity differences between trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium, it is essential that chromium be quantified in these two distinct valence states to assess the potential risks to exposure to each in environmental media. Speciation is equally important because of their marked differences in environmental behavior. As the knowledge of risks associated with each valence state has grown and regulatory requirements have evolved, methods to accurately quantitate these species at ever-decreasing concentrations within environmental media have also evolved. This paper addresses the challenges of chromium species quantitation and some of the most relevant current methods used for environmental monitoring, including ASTM Method D5281 for air, SW-846 Methods 3060A, 7196A and 7199 for soils, sediments, and waste, and U.S. EPA Method 218.6 for water. PMID:9380841

  9. METHODS FOR THE DETERMINATION OF TOTAL ORGANIC CARBON (TOC) IN SOILS AND SEDIMENTS

    EPA Science Inventory

    Organic matter in soils and sediments is widely distributed over the earth's surface occurring in almost all terrestrial and aquatic environments (Schnitzer, 1978). Soils and sediments contain a large variety of organic materials ranging from simple sugars and carbohydrates to th...

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

    PubMed

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

    2006-01-01

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

  11. Effects of biochar on soil infiltration, runoff and sediment production on a slopeland red soil

    NASA Astrophysics Data System (ADS)

    Jien, Shih-Hao; Chen, Jyun-Yuan; Liao, Chien-Sen

    2016-04-01

    Biochar has been considered as a useful amendment to ameliorate soil physical and chemical properties. This study aims to incorporate a wood biochar (WB), pyrolized by 400℃, into a clayey red soil with a slope gradient of 5o to improve infiltration and reduce runoff and sediment production. Field trials were conducted in four treatments including control, biochar (4%, w/w) (WB), compost (1%) + biochar (4%) (CWB) and polyacrylamide in 50 ppm (PAM) in this study. An erosion experiment was performed by a rainfall simulator in a rainfall intensity of 70 mm/hr after 12 months. The runoff and sediments were collected and weighted for each treatment. The results displayed that runoff amounts were obviously reduced by 2.3% -6.3% in treatments of WB and CWB compared with the control, but not in PAM. On contrary, the infiltration rates were obviously increased by 7.4%-18% in the treatment of WB and CWB compared with the control, but reduced by 25% in PAM treatment. After 12 months, all treatments could effectively prevent clayey soil from erosion, particularly in PAM. In conclusion, biochar could be an alternative strategy for improvement of permeability and erodibility compared with PAM practice on mild slopeland soils.

  12. DUS II SOIL GAS SAMPLING AND AIR INJECTION TEST RESULTS

    SciTech Connect

    Noonkester, J.; Jackson, D.; Jones, W.; Hyde, W.; Kohn, J.; Walker, R.

    2012-09-20

    Soil vapor extraction (SVE) and air injection well testing was performed at the Dynamic Underground Stripping (DUS) site located near the M-Area Settling Basin (referred to as DUS II in this report). The objective of this testing was to determine the effectiveness of continued operation of these systems. Steam injection ended on September 19, 2009 and since this time the extraction operations have utilized residual heat that is present in the subsurface. The well testing campaign began on June 5, 2012 and was completed on June 25, 2012. Thirty-two (32) SVE wells were purged for 24 hours or longer using the active soil vapor extraction (ASVE) system at the DUS II site. During each test five or more soil gas samples were collected from each well and analyzed for target volatile organic compounds (VOCs). The DUS II site is divided into four parcels (see Figure 1) and soil gas sample results show the majority of residual VOC contamination remains in Parcel 1 with lesser amounts in the other three parcels. Several VOCs, including tetrachloroethylene (PCE) and trichloroethylene (TCE), were detected. PCE was the major VOC with lesser amounts of TCE. Most soil gas concentrations of PCE ranged from 0 to 60 ppmv with one well (VEW-22A) as high as 200 ppmv. Air sparging (AS) generally involves the injection of air into the aquifer through either vertical or horizontal wells. AS is coupled with SVE systems when contaminant recovery is necessary. While traditional air sparging (AS) is not a primary component of the DUS process, following the cessation of steam injection, eight (8) of the sixty-three (63) steam injection wells were used to inject air. These wells were previously used for hydrous pyrolysis oxidation (HPO) as part of the DUS process. Air sparging is different from the HPO operations in that the air was injected at a higher rate (20 to 50 scfm) versus HPO (1 to 2 scfm). . At the DUS II site the air injection wells were tested to determine if air sparging affected

  13. Study of sediment movement in an irrigated maize-cotton system combining rainfall simulations, sediment tracers and soil erosion models

    NASA Astrophysics Data System (ADS)

    Guzmán, Gema; Laguna, Ana; Cañasveras, Juan Carlos; Boulal, Hakim; Barrón, Vidal; Gómez-Macpherson, Helena; Giráldez, Juan Vicente; Gómez, José Alfonso

    2015-05-01

    Although soil erosion is one of the main threats to agriculture sustainability in many areas of the world, its processes are difficult to measure and still need a better characterization. The use of iron oxides as sediment tracers, combined with erosion and mixing models opens up a pathway for improving the knowledge of the erosion and redistribution of soil, determining sediment sources and sinks. In this study, magnetite and a multivariate mixing model were used in rainfall simulations at the micro-plot scale to determine the source of the sediment at different stages of a furrow-ridge system both with (+T) and without (-T) wheel tracks. At a plot scale, magnetite, hematite and goethite combined with two soil erosion models based on the kinematic wave approach were used in a sprinkler irrigation test to study trends in sediment transport and tracer dynamics along furrow lengths under a wide range of scenarios. In the absence of any stubble cover, sediment contribution from the ridges was larger than the furrow bed one, almost 90%, while an opposite trend was observed with stubble, with a smaller contribution from the ridge (32%) than that of the bed, at the micro-plot trials. Furthermore, at a plot scale, the tracer concentration analysis showed an exponentially decreasing trend with the downstream distance both for sediment detachment along furrows and soil source contribution from tagged segments. The parameters of the distributed model KINEROS2 have been estimated using the PEST Model to obtain a more accurate evaluation. Afterwards, this model was used to simulate a broad range of common scenarios of topography and rainfall from commercial farms in southern Spain. Higher slopes had a significant influence on sediment yields while long furrow distances allowed a more efficient water use. For the control of runoff, and therefore soil loss, an equilibrium between irrigation design (intensity, duration, water pattern) and hydric needs of the crops should be

  14. Determination of polybrominated diphenyl ethers in soils and sediment of Hanfeng Lake, Three Gorges.

    PubMed

    Zhang, Wenrui; Lu, Yingzhuan; Gao, Shutao; Jia, Xuwei; Yu, Zhiqiang; Zeng, Xiangying; Sheng, Guoying; Fu, Jiamo

    2015-01-01

    As ubiquitous organic contaminants, polybrominated diphenyl ethers (PBDEs) were evaluated to explore the impacts of the water level fluctuating zone (WLFZ) on organic pollutant behavior and the retention mechanism of organic pollutants in the bank-WLFZ-water system of Hanfeng Lake in the Three Gorges region of China. The mean concentrations of total PBDEs were 103, 75.2, and 568 ng g(-1) dry wt for bank soils, WLFZ soils, and sediment samples, respectively. Except for sampling sites S1 and S2, the levels of PBDEs decreased in the order of sediment>WLFZ soil > bank soil, suggesting that PBDEs were transferred from bank soil to WLFZ soil and finally deposited in the sediment. Decabromodiphenyl ethers (deca-BDEs) were the predominant congener in the study area, comprising 93.8% to 98.3% of the total PBDEs. Greater photolytic degradation of deca-BDEs was suggested in bank soils based on a higher relative abundance of octa- and nona-BDEs than in WLFZ soils and sediment. This may have occurred because deca-BDEs in bank soils have relatively longer sunlight exposure than in WLFZ soils and sediment due to the annual alternation of water storage and drainage in the catchments of the Three Gorges Reservoir. More in-depth investigations of contaminants in bank-WLFZ-water systems are needed due to the large areas of WLFZ created by the construction of the Three Gorges Dam and their importance to the balance of aquatic ecosystems. PMID:26181085

  15. Determination of polybrominated diphenyl ethers in soils and sediment of Hanfeng Lake, Three Gorges.

    PubMed

    Zhang, Wenrui; Lu, Yingzhuan; Gao, Shutao; Jia, Xuwei; Yu, Zhiqiang; Zeng, Xiangying; Sheng, Guoying; Fu, Jiamo

    2015-01-01

    As ubiquitous organic contaminants, polybrominated diphenyl ethers (PBDEs) were evaluated to explore the impacts of the water level fluctuating zone (WLFZ) on organic pollutant behavior and the retention mechanism of organic pollutants in the bank-WLFZ-water system of Hanfeng Lake in the Three Gorges region of China. The mean concentrations of total PBDEs were 103, 75.2, and 568 ng g(-1) dry wt for bank soils, WLFZ soils, and sediment samples, respectively. Except for sampling sites S1 and S2, the levels of PBDEs decreased in the order of sediment>WLFZ soil > bank soil, suggesting that PBDEs were transferred from bank soil to WLFZ soil and finally deposited in the sediment. Decabromodiphenyl ethers (deca-BDEs) were the predominant congener in the study area, comprising 93.8% to 98.3% of the total PBDEs. Greater photolytic degradation of deca-BDEs was suggested in bank soils based on a higher relative abundance of octa- and nona-BDEs than in WLFZ soils and sediment. This may have occurred because deca-BDEs in bank soils have relatively longer sunlight exposure than in WLFZ soils and sediment due to the annual alternation of water storage and drainage in the catchments of the Three Gorges Reservoir. More in-depth investigations of contaminants in bank-WLFZ-water systems are needed due to the large areas of WLFZ created by the construction of the Three Gorges Dam and their importance to the balance of aquatic ecosystems.

  16. Air distribution and size changes in the remediated zone after air sparging for soil particle movement.

    PubMed

    Tsai, Yih-Jin

    2008-10-30

    In an unconsolidated porous medium, soil particles can be mobilized by physical perturbation. In model systems of fluids flowing over spherical particles attached to flat surfaces, the hydrodynamic shear force depends on the fluid viscosity, particle radius, and flow velocity. Soil particles can be reasonably expected to be transported by flowing water during air sparging when the particle-size distribution does not fit the densest possible particle arrangement. If soil particles are transported during air sparging, then the distribution of the porosity and reservoir permeability will change. The remediated zone changes because of the changes in soil characteristics. This study applied some mathematical models to elucidate the mobilization process of soil particles during in situ air sparging. The changes in the characteristics of the soil and the swept volume of injected air during air sparging were also investigated. The results demonstrated that particle movement reduced the radius of influence (ROI) and the swept volume of injected air. In this case study, the maximum reducing rates in ROI and the swept volume were 24% and 26% for the zone where the gas saturation exceeded 10%.

  17. Radioactivity in soils and sediments in and adjacent to the Los Alamos area, 1974-1977

    SciTech Connect

    Purtymun, W.D.; Peters, R.J.; Stoker, A.K.

    1980-02-01

    Soils and sediments are analyzed for gross alpha, gross beta, /sup 238/Pu, /sup 239/Pu, /sup 137/Cs, /sup 90/Sr, and total uranium as part of the continuing Environmental Monitoring Program at the Los Alamos Scientific Laboratory. This report documents the levels of radioactivity of radionuclides in soils and sediments in northern New Mexico from natural sources and worldwide fallout as well as at seven on-site soil and sediment stations which contain radioactivity contributed by the Laboratory for the period 1974 through 1977.

  18. Effect of aggregation on SOC transport: linking soil properties to sediment organic matter

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2016-04-01

    Soils are an interface between the Earth's spheres and shaped by the nature of the interaction between them. The relevance of soil properties for the nature of the interaction between atmosphere, hydrosphere and biosphere is well-studied and accepted, on point- or ecotone-scale. However, this understanding of the largely vertical connections between spheres is not matched by a similar recognition of soil properties affecting processes acting largely in a lateral way across the land surface, such as erosion, transport and deposition of soil and the associated organic matter. Understanding the redistribution of eroded soil organic matter falls into several disciplines, most notably soil science, agronomy, hydrology and geomorphology, and recently into biogeochemistry. Accordingly, the way soil and sediment are described differs: in soil science, aggregation and structure are essential properties, while most process-based soil erosion models treat soil as a mixture of individual mineral grains, based on concepts derived in fluvial geomorphology or civil engineering. The actual behavior of aggregated sediment and the associated organic matter is not reflected by either approach and difficult to capture due to the dynamic nature of aggregation, especially in an environment such as running water. Still, a proxy to assess the uncertainties introduced by aggregation on the behavior of soil/sediment organic while moving in water across landscapes and into the aquatic system would represent a major step forward. To develop such a proxy, a database collating relevant soil, organic matter and sediment properties could serve as an initial step to identify which soil types and erosion scenarios are prone to generate a high uncertainty compared to the use of soil texture in erosion models. Furthermore, it could serve to develop standardized analytical procedures for appropriate description of soil and organic matter as sediment.

  19. Control of aromatic-waste air streams by soil bioreactors

    SciTech Connect

    Miller, D.E.; Canter, L.W.

    1991-01-01

    Contamination of groundwater resources is a serious environmental problem which is continuing to increase in occurrence in the United States. It has been reported that leaking underground gasoline storage tanks may pose the most serious threat of all sources of groundwater contamination. Gasolines are comprised of a variety of aliphatic and aromatic hydrocarbons. The aromatic portion consists primarily of benzene, toluene, ethylbenzene, and xylenes (BTEX compounds). BTEX compounds are also among the most frequency identified substances at Superfund sites. Pump and treat well systems are the most common and frequently used technique for aquifer restoration. Treatment is often in the form of air stripping to remove the volatile components from the contaminated water. Additionally, soil ventilation processes have been used to remove volatile components from the vadose zone. Both air stripping and soil ventilation produce a waste gas stream containing volatile compounds which is normally treated by carbon adsorption or incineration. Both treatment processes require a substantial capital investment and continual operation and maintenance expenditures. The objective of the study was to examine the potential of using soil bioreactors to treat a waste gas stream produced by air stripping or soil ventilation process. Previous studies have shown that various hydrocarbons can be successfully treated with soils. The study examined the removal of BTEX compounds within soil columns and the influence of soil type, inlet concentration, and inlet flow rate on the removal efficiency.

  20. Controls on catchment-scale patterns of phosphorus in soil, streambed sediment, and stream water.

    PubMed

    van der Perk, Marcel; Owens, Philip N; Deeks, Lynda K; Rawlins, Barry G; Haygarth, Philip M; Beven, Keith J

    2007-01-01

    Many models of phosphorus (P) transfer at the catchment scale rely on input from generic databases including, amongst others, soil and land use maps. Spatially detailed geochemical data sets have the potential to improve the accuracy of the input parameters of catchment-scale nutrient transfer models. Furthermore, they enable the assessment of the utility of available, generic spatial data sets for the modeling and prediction of soil nutrient status and nutrient transfer at the catchment scale. This study aims to quantify the unique and joint contribution of soil and sediment properties, land cover, and point-source emissions to the spatial variation of P concentrations in soil, streambed sediments, and stream water at the scale of a medium-sized catchment. Soil parent material and soil chemical properties were identified as major factors controlling the catchment-scale spatial variation in soil total P and Olsen P concentrations. Soil type and land cover as derived from the generic spatial database explain 33.7% of the variation in soil total P concentrations and 17.4% of the variation in Olsen P concentrations. Streambed P concentrations are principally related to the major element concentrations in streambed sediment and P delivery from the hillslopes due to sediment erosion. During base flow conditions, the total phosphorus (<0.45 microm) concentrations in stream water are mainly controlled by the concentrations of P and the major elements in the streambed sediment.

  1. Integration of remote sensing, RUSLE and GIS to model potential soil loss and sediment yield (SY)

    NASA Astrophysics Data System (ADS)

    Kamaludin, H.; Lihan, T.; Rahman, Z. Ali; Mustapha, M. A.; Idris, W. M. R.; Rahim, S. A.

    2013-04-01

    Land use activities within a basin serve as one of the contributing factors which cause deterioration of river water quality through its potential effect on erosion. Sediment yield in the form of suspended solid in the river water body which is transported to the coastal area occurs as a sign of lowering of the water quality. Hence, the aim of this study was to determine potential soil loss using the Revised Universal Soil Loss Equation (RUSLE) model and the sediment yield, in the Geographical Information Systems (GIS) environment within selected sub-catchments of Pahang River Basin. RUSLE was used to estimate potential soil losses and sediment yield by utilizing information on rainfall erosivity (R) using interpolation of rainfall data, soil erodibility (K) using field measurement and soil map, vegetation cover (C) using satellite images, topography (LS) using DEM and conservation practices (P) using satellite images. The results indicated that the rate of potential soil loss in these sub-catchments ranged from very low to extremely high. The area covered by very low to low potential soil loss was about 99%, whereas moderate to extremely high soil loss potential covered only about 1% of the study area. Sediment yield represented only 1% of the potential soil loss. The sediment yield (SY) value in Pahang River turned out to be higher closer to the river mouth because of the topographic character, climate, vegetation type and density, and land use within the drainage basin.

  2. Heavy metal enrichment in the riparian sediments and soils of the Three Gorges Reservoir, China

    NASA Astrophysics Data System (ADS)

    Tang, Q.; Bao, Y.; He, X.; Wen, A.

    2015-03-01

    The Three Gorges Reservoir encompasses a riparian zone with a vertical height of 30 m and a total area of 349 km2 that has been subjected to alternate inundation and exposure due to regular impoundment. Sedimentation on the riparian landforms constitutes an important pathway for riverine contaminant redistribution. In an attempt to understand heavy metal enrichment since water inundation, riparian sediments and soils were sampled along five transects in a typical riparian zone composed of cultivated bench terraces in the middle reaches. Heavy metals (Cr, Ni, Cu, Zn, As, Cd and Pb) were determined to characterize the lateral distribution and vertical transfer ratio. The results indicated that all heavy metals were enriched to varying extents both in the riparian sediments and soils, compared with regional background contents in soils and the reference levels in sediments. However, heavy metal levels in the riparian sediments were generally higher than those in the riparian soils, while those in the upper riparian soils (0-5 cm) were overall slightly higher than those in the lower riparian soils (5-10 cm). There was a decreasing trend of heavy metal contents with increasing elevation. The elevated levels of heavy metals in the riparian sediments may be attributed to sediment yields from upstream anthropogenic sources, especially during major rainstorms in the wet season when large loads of contaminated sediment may be produced from diffuse source areas. Heavy metals can also be adsorbed to pure sediment in the course of mobilization or after deposition. Considering that the riparian soils are local weathering products without mobilization, the enrichment of heavy metals may principally be ascribed to chemical adsorption from dissolved fractions or vertical transfer from overlaid sediments. Heavy metal enrichment may further be affected by the specific type of hydrologic regime such that relatively long flooding duration caused by water impoundment and natural floods

  3. Long-term sediment yield from small catchment in southern Brazil affected by land use and soil management changes.

    NASA Astrophysics Data System (ADS)

    Gomes Minella, Jean Paolo; Henrique Merten, Gustavo; Alessandra Peixoto de Barros, Claudia; Dalbianco, Leandro; Ramon, Rafael; Schlesner, Alexandre

    2015-04-01

    Soil erosion and sediment yield are the main cause of soil degradation in Brazil. Despite this, there is a lack of information about the effects of the soil management on the hydrology and sediment yield at catchment scale. This study aimed to investigate the long-term relationship between the land use and sediment yield in a small catchment with significant changes in soil management, and its impacts on soil erosion and sediment yield. To account the anthropogenic and climatic effects on sediment yield were monitored precipitation, stream flow and suspended sediment concentration during thirteen years (2002 and 2014) at 10 minutes interval and the changes that occurred each year in the land use and soil management. Despite the influence of climate on the sediment yield, the results clearly show three distinct periods affected by the land use and soil management changes during this this period. In the first four years (2002-2004) the predominant land use was the tobacco with traditional soil management, where the soils are plough every year and without winter cover crop. In this period the sediment yield reached the order of 160 t.ha-1.y-1. In the period of 2005-2009, a soil conservation program introduced the adoption of minimum tillage in the catchment and the sediment yield decrease to 70 t.ha-1.y-1. In the last period (2010-2014) there was a partial return to the traditional soil management practices with an increase trend in sediment yield. However, there was also an increase in reforestation areas with positive effect in reducing erosion and sediment yield. The magnitude order of sediment yield in this period was 100 t.ha-1.y-1. The long term sediment yield data was able to demonstrate the impact of the improved management practices in reducing soil erosion and sediment yield. The results allowed a good understanding of the changing sediment dynamics and soil erosion at catchment scale.

  4. Soil, Groundwater, Surface Water, and Sediments of Kennedy Space Center, Florida: Background Chemical and Physical Characteristics

    NASA Technical Reports Server (NTRS)

    Shmalzer, Paul A.; Hensley, Melissa A.; Mota, Mario; Hall, Carlton R.; Dunlevy, Colleen A.

    2000-01-01

    This study documented background chemical composition of soils, groundwater, surface; water, and sediments of Kennedy Space Center. Two hundred soil samples were collected, 20 each in 10 soil classes. Fifty-one groundwater wells were installed in 4 subaquifers of the Surficial Aquifer and sampled; there were 24 shallow, 16 intermediate, and 11 deep wells. Forty surface water and sediment samples were collected in major watershed basins. All samples were away from sites of known contamination. Samples were analyzed for organochlorine pesticides, aroclors, chlorinated herbicides, polycyclic aromatic hydrocarbons (PAH), total metals, and other parameters. All aroclors (6) were below detection in all media. Some organochlorine pesticides were detected at very low frequencies in soil, sediment, and surface water. Chlorinated herbicides were detected at very low frequencies in soil and sediments. PAH occurred in low frequencies in soiL, shallow groundwater, surface water, and sediments. Concentrations of some metals differed among soil classes, with subaquifers and depths, and among watershed basins for surface water but not sediments. Most of the variation in metal concentrations was natural, but agriculture had increased Cr, Cu, Mn, and Zn.

  5. Air sparging in low permeability soils

    SciTech Connect

    Marley, M.C.

    1996-08-01

    Sparging technology is rapidly growing as a preferred, low cost remediation technique of choice at sites across the United States. The technology is considered to be commercially available and relatively mature. However, the maturity is based on the number of applications of the technology as opposed to the degree of understanding of the mechanisms governing the sparging process. Few well documented case studies exist on the long term operation of the technology. Sparging has generally been applied using modified monitoring well designs in uniform, coarse grained soils. The applicability of sparging for the remediation of DNAPLs in low permeability media has not been significantly explored. Models for projecting the performance of sparging systems in either soils condition are generally simplistic but can be used to provide general insight into the effects of significant changes in soil and fluid properties. The most promising sparging approaches for the remediation of DNAPLs in low permeability media are variations or enhancements to the core technology. Recirculatory sparging systems, sparging/biosparging trenches or curtains and heating or induced fracturing techniques appear to be the most promising technology variants for this type of soil. 21 refs., 9 figs.

  6. Biotransformation of tetrabromobisphenol A (TBBPA) in anaerobic digester sludge, soils, and freshwater sediments.

    PubMed

    McAvoy, Drew C; Pittinger, Charles A; Willis, Alison M

    2016-09-01

    The biotransformation of tetrabromobisphenol A (TBBPA) was evaluated in anaerobic digester sludge, soils, and freshwater sediments. In anaerobic digester sludge, TBBPA biotransformed rapidly with a 50% disappearance time (DT50) of 19 days, though little mineralization (1.1%) was observed. In aerobic soils, mineralization of TBBPA ranged from 17.5% to 21.6% with 55.3-83.6% of the TBBPA incorporated into the soils as a non-extractable bound residue. The DT50 for TBBPA in aerobic soils ranged from 5.3 to 7.7 days. In anaerobic soils, 48.3-100% of the TBBPA was incorporated into the soils as non-extractable bound residue with <4% mineralized. The soil fate studies demonstrated extensive incorporation of TBBPA into the solid matrix and this association was related to the amount of organic carbon in the soils (i.e., greater association of TBBPA with soil at higher organic carbon content). In anaerobic sediments the DT50 for TBBPA ranged from 28 to 42 days, whereas in aerobic sediments the DT50 for TBBPA ranged from 48 to 84 days and depended on the initial dose concentration. Most of the TBBPA in the sediment studies was incorporated as a non-extractable bound residue with little mineralization observed. Sediment extracts revealed three unknown biotransformation products and bisphenol A (BPA). These results were consistent with previously published studies where TBBPA biotransformed in anaerobic environments (digester sludge and sediments) by debromination and slowly mineralized in the test environments (anaerobic digester sludge, soils, and freshwater sediments).

  7. METAL SPECIATION IN SOIL, SEDIMENT, AND WATER SYSTEMS VIA SYNCHROTRON RADIATION RESEARCH

    EPA Science Inventory

    Metal contaminated environmental systems (soils, sediments, and water) have challenged researchers for many years. Traditional methods of analysis have employed extraction methods to determine total metal content and define risk based on the premise that as metal concentration in...

  8. DYNAMICS OF MINERAL STRUCTURES AND THE FATE OF METALS IN SOILS AND SEDIMENTS

    EPA Science Inventory

    Significant progress has been made in elucidating sorption reactions that control the partitioning of metals from solution to mineral surfaces in contaminated soil/sediment systems. Surface complexation models have been developed to quantify the forward reaction with reasonable ...

  9. Development and application of immunoaffinity chromatography for coplanar PCBs in soil and sediment.

    PubMed

    Van Emon, Jeanette M; Chuang, Jane C

    2013-01-01

    An immunoaffinity chromatography (IAC) column was developed as a simple cleanup procedure for preparing environmental samples for analysis of polychlorinated biphenyls (PCBs). Soil and sediment samples were prepared using pressurized liquid extraction (PLE), followed by the IAC cleanup, with detection by an enzyme-linked immunosorbent assay (ELISA). Quantitative recoveries (84-130%) of PCB-126 were obtained in fortified sediment and soil samples using the PLE/IAC/ELISA method. These results demonstrated that the IAC procedure effectively removed interferences from the soil and sediment matrices. The IAC column could be reused more than 20 times with no change in performance with 99.9% methanol/0.1% Triton X-100 as the elution solvent. Results of 17 soil and sediment samples prepared by PLE/IAC/ELISA correlated well with those obtained from a conventional multi-step cleanup with gas chromatography/mass spectrometry detection.

  10. Development and Application of Immunoaffinity Chromatography for Coplanar PCBs in Soil and Sediment

    EPA Science Inventory

    An immunoaffinity chromatography (IAC) column was developed as a simple cleanup procedure for preparing environmental samples for analysis of polychlorinated biphenyls (PCBs). Soil and sediment samples were prepared using pressurized liquid extraction (PLE), followed by the IAC c...

  11. THE INFLUENCE OF MINERAL REACTIONS ON THE ENVIRONMENTAL FATE OF METALS IN SOILS AND SEDIMENTS

    EPA Science Inventory

    Significant progress has been made in elucidating sorption reactions that control the partitioning of metals from solution to mineral surfaces in contaminated soil/sediment systems. Surface complexation models have been developed to quantify the forward reaction, however, these ...

  12. Ecoenzymatic Stoichiometry of Microbial Organic Nutrient Acquisition in Soil and Sediment

    EPA Science Inventory

    Terrestrial soils and freshwater sediments contain reserves of organic carbon estimated at 1500 Pg and 0.2 Pg, respectively. Mineralization of this organic matter by heterotrophic microorganisms drives global carbon and nutrient cycles, controlling plant production and atmospher...

  13. NEW GIS WATERSHED ANALYSIS TOOLS FOR SOIL CHARACTERIZATION AND EROSION AND SEDIMENTATION MODELING

    EPA Science Inventory

    A comprehensive procedure for computing soil erosion and sediment delivery metrics has been developed which utilizes a suite of automated scripts and a pair of processing-intensive executable programs operating on a personal computer platform.

  14. Psychrotrophic lipase producers from Arctic soil and sediment samples.

    PubMed

    Rasol, R; Rashidah, A R; Nazuha, R Siti Nur; Smykla, J; Maznah, W O Wan; Alias, S A

    2014-01-01

    Culturable microorganisms were successfully isolated from soil and sediment samples collected in 2011 on the northern coast of Hornsund, West Spitsbergen. A total of 63 single colony isolates from three sampling sites obtained were subjected to temperature dependence study to assess whether they are obligate psychrophilic or psychrotrophic strains. From initial temperature screening, only 53 psychrotrophic isolates were selected that are capable of growing between 4-28 degrees C. The rest that were capable of tolerating higher temperatures up to 37 degrees C were not included in this study. These isolates were chosen for lipase enzyme screening confirmation with the standard plate assay of olive oil and fluorescent dye Rhodamine B. Six lipase positive isolates were also subjected for subsequent lipase enzyme plate screening on tributyrin, triolein, olive oil and palm oil agar. Lipase production by these six isolates was further assayed by using colorimetric method with palm oil and olive oil as the substrate. These isolates with promising lipase activity ranging from 20 U/ml up to 160 U/ml on palm oil and olive oil substrate were successfully identified. Molecular identification by using 16S rRNA revealed that five out of six isolates were Gram-negative Proteobacteria and the other one was a Gram-positive Actinobacteria. PMID:25033666

  15. Laboratory measurements of upwelled radiance and reflectance spectra of Calvert, Ball, Jordan, and Feldspar soil sediments

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Usry, J. W.; Witte, W. G.; Gurganus, E. A.

    1977-01-01

    An effort to investigate the potential of remote sensing for monitoring nonpoint source pollution was conducted. Spectral reflectance characteristics for four types of soil sediments were measured for mixture concentrations between 4 and 173 ppm. For measurements at a spectral resolution of 32 mm, the spectral reflectances of Calvert, Ball, Jordan, and Feldspar soil sediments were distinctly different over the wavelength range from 400 to 980 nm at each concentration tested. At high concentrations, spectral differences between the various sediments could be detected by measurements with a spectral resolution of 160 nm. At a low concentration, only small differences were observed between the various sediments when measurements were made with 160 nm spectral resolution. Radiance levels generally varied in a nonlinear manner with sediment concentration; linearity occurred in special cases, depending on sediment type, concentration range, and wavelength.

  16. Phosphorus adsorption and desorption potential of stream sediments and field soils in agricultural watersheds.

    PubMed

    Agudelo, Sandra C; Nelson, Nathan O; Barnes, Philip L; Keane, Timothy D; Pierzynski, Gary M

    2011-01-01

    Phosphorus release from stream sediments into water could increase P loads leaving agricultural watersheds and contribute to lag-time between implementation of best management practices and improvement in water quality. Improved understanding of P release from stream sediments can assist in setting water quality goals and designing stream monitoring programs. The objective of this study was to estimate the relative potential of sediments and soils to release P to stream water in two agricultural watersheds. Stream sediments were collected from banks, pools, riffles, and depositional features. Soils were sampled from wheat, row crop, pasture, and manure-amended fields. Sediments and soils were analyzed for equilibrium P concentration at zero net P sorption (EPC0), maximum P adsorption capacity (P(max)), anion exchange extractable P (P(lab)), and degree of P saturation. Dissolved reactive P (DRP) of stream water was monitored. Stream sediment EPC0 was similar to or less than EPC0 from field soils; however, P(lab) of stream sediments was three times less than field soils. Sediments were sandy and had low P(max) due to low oxalate-extractable Fe and Al, which could be explained by stream geomorphology. Manure-amended fields had the highest EPC0 and P(lab) due to continued inputs of manure-based P; however, conventionally fertilized fields also represented an important P source due to their vast extent. Stream water DRP was similar to EPC0 of sediments during base flow and similar to EPC0 of field soils during storm flow. These results indicate that sediments in these streams are a relatively minor P source. PMID:21488503

  17. Root-soil air gap and resistance to water flow at the soil-root interface of Robinia pseudoacacia.

    PubMed

    Liu, X P; Zhang, W J; Wang, X Y; Cai, Y J; Chang, J G

    2015-12-01

    During periods of water deficit, growing roots may shrink, retaining only partial contact with the soil. In this study, known mathematical models were used to calculate the root-soil air gap and water flow resistance at the soil-root interface, respectively, of Robinia pseudoacacia L. under different water conditions. Using a digital camera, the root-soil air gap of R. pseudoacacia was investigated in a root growth chamber; this root-soil air gap and the model-inferred water flow resistance at the soil-root interface were compared with predictions based on a separate outdoor experiment. The results indicated progressively greater root shrinkage and loss of root-soil contact with decreasing soil water potential. The average widths of the root-soil air gap for R. pseudoacacia in open fields and in the root growth chamber were 0.24 and 0.39 mm, respectively. The resistance to water flow at the soil-root interface in both environments increased with decreasing soil water potential. Stepwise regression analysis demonstrated that soil water potential and soil temperature were the best predictors of variation in the root-soil air gap. A combination of soil water potential, soil temperature, root-air water potential difference and soil-root water potential difference best predicted the resistance to water flow at the soil-root interface.

  18. Impacts of runoff from sulfuric soils on sediment chemistry in an estuarine lake.

    PubMed

    Macdonald, Bennett C T; Smith, Jodie; Keene, Annabelle F; Tunks, Mark; Kinsela, Andrew; White, Ian

    2004-08-15

    The impact of runoff from sulfuric soils in the heavily drained Cudgen Lake floodplain, eastern Australia on water quality and downstream coastal lake sediments has been examined. The oxidation of sulfidic soils and the transformation into sulfuric soils leads to changes not only in the upper soil profile but also affects drainage water quality and the chemistry of bottom sediments in receiving waters. Oxidation transforms the soil from a sink for sulfur and metals to a significant source for downstream environments. Sulfuric soils within the Cudgen Lake catchment contain 9.18 x 10(5) mol H+ per hectare as well as elevated concentration of metals (e.g. Al, Fe, Mn) and sulfate. These products of sulfidic soil oxidation are transported efficiently from the soil profile by the constructed drainage network and into the downstream lake system. The acid volatile sulfur (AVS), chromium reducible sulfur (CRS), total sulfur, organic carbon, and reactive iron contents present in the solid phase of the lake sediments are reported. The AVS/CRS, DOP and DOS values observed in the lake sediments show that natural monosulfide formation in the near surface sediments has been enhanced due to increased inputs of organic matter, sulfate, ferrous iron and other metals following development of the catchment. There are elevated concentrations of metals (e.g. As, Al, Cd, Cr, Hg, Zn and Pb) in the upper layer of monosulfidic lake sediments compared with the underlying pyritic sediments some of which exceed sediment quality guidelines. These metals could be released by dredging or through re-suspension during high flow conditions or enter the food chain.

  19. Presumptive remedies for soils, sediments, and sludges at wood treater sites

    SciTech Connect

    1995-12-01

    The purpose of this directive is to provide guidance on selecting a presumptive remedy or combination of presumptive remedies for wood treater sites with contaminated soils, sediments, and sludges. Specifically, this guidance; describes the contaminants generally found at wood treater sites; presents the presumptive remedies for contaminated soils, sediments, and sludges at wood treater sites; describes the presumptive remedy process concerning the site characterization and technology screening steps; and outlines the data that should be used to select a presumptive remedy.

  20. A multi-component statistic analysis for the influence of sediment/soil composition on the sorption of a nonionic surfactant (Triton X-100) onto natural sediments/soils.

    PubMed

    Zhu, Lizhong; Yang, Kun; Lou, Baofeng; Yuan, Bihao

    2003-11-01

    The contents of soil/sediment organic carbon and clay minerals (i.e. montmorillonite, kaolinite, illite, gibbsite and 1.4 nm minerals) for 21 natural soil/sediment samples and the sorption of Triton X-100 on these samples were determined. A multi-component statistic analysis was employed to investigate the importance of soil/sediment organic matters and clay minerals on their sorption of Triton X-100. The sorption power of soil/sediment composition for Triton X-100 conforms to an order of montmorillonite>organic carbon>illite>1.4 nm minerals (vermiculite+chlorite+1.4 nm intergrade mineral)>kaolinite. The sorption of Triton X-100 on a montmorillonite, a kaolinite and a humic acid were also investigated and consistent with the result of multi-component statistic analysis. It is clear that the sorption of Triton X-100 on soils or sediments is the combined contribution of soil/sediment organic matters and clay minerals, which depended on both the contents of soil/sediment organic matters and the types and contents of clay minerals. The important influence of illite on the sorption of nonionic surfactants onto soils/sediments is suggested and demonstrated in this paper. Surfactants for aquifer remediation application may be more efficient for the contaminated soils/sediments that contain little clay minerals with 2:1 structure because of the less sorption of nonionic surfactants on these soils/sediments.

  1. Assessment of herbicide sorption by biochars and organic matter associated with soil and sediment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorption of two herbicides, fluridone (FLUN) and norflurazon (NORO), by whole sediment, two types of biochars and various soil/sediment organic matter (OM) fractions including nonhydrolyzable carbon (NHC), black carbon (BC) and humic acid (HA) was examined. The single-point organic carbon (OC)-norma...

  2. Soil Surface Carbon Dioxide Fluxes and Carbon Dioxide Concentrations in Soil Air

    NASA Astrophysics Data System (ADS)

    Arkebauer, T. J.; Billesbach, D.

    2006-12-01

    We have been monitoring soil surface CO2 fluxes at three AmeriFlux sites in eastern Nebraska for several years. Recently, we have installed soil CO2 sensors at the rainfed soybean site in order to obtain profiles of CO2 concentrations in soil air (to 0.8 m depth). Supporting data include profiles of soil water content and soil temperature, aboveground biomass, leaf area index and precipitation. Soil surface fluxes had been rather small for much of the 2006 growing season (e.g., midday values of about 5 umol/m2/s) due, in large part, to the very dry conditions in eastern Nebraska and the consequent low soil water contents. However, copious rainfall in August raised soil water contents to field capacity throughout the profile. Soil air CO2 concentrations during this period also increased and reached peaks near 10% (at 0.4 and 0.8 m depth). Through analyses of relationships between surface CO2 flux and profiles of soil parameters we seek to identify biophysical factors responsible for controlling surface fluxes as well as to begin to quantify sources and sinks of CO2 within the soil profile (e.g., plant-related production of CO2 due to root exudation and respiration). The influence of precipitation events on CO2 profiles and fluxes is of particular interest.

  3. Polycyclic aromatic hydrocarbons in water, sediment, soil, and plants of the Aojiang River waterway in Wenzhou, China

    PubMed Central

    Li, Jianwang; Shang, Xu; Zhao, Zhixu; Tanguay, Robert L.; Dong, Qiaoxiang; Huang, Changjiang

    2012-01-01

    The town of Shuitou was renowned as the leather capital of China because of its large-scale tanning industry, but the industry’s lack of pollution controls has caused severe damage to the local water system. This study determined 15 priority polycyclic aromatic hydrocarbons (PAHs) in water, sediment, soil, and plant samples collected from Aojiang River and its estuary. The total PAHs ranged from 910 to 1520 ng/L in water samples. The total PAH in sediments were moderate to low in comparison with other rivers and estuaries in China, but the relative proportions of PAHs per million people are high when considering the population size associated with each watershed. Ratios of fluoranthene/pyrene and PAHs with low/high molecular weight suggest a petrogenic PAH origin. The PAH composition profile in soil was similar to that in sediment with 4–6 ring PAHs being dominant. The PAHs with 2–3 rings were the dominant species in plant leaves. There were no correlations between PAHs in soils and in plants, suggesting that PAHs accumulate in plant leaves through absorption from the air. The general observation of elevated PAH concentrations in all matrix suggests a possible contribution by the local leather industry on the PAH concentrations in the Aojiang watershed. PMID:19726127

  4. In Situ Representation of Soil/Sediment Conductivity Using Electrochemical Impedance Spectroscopy

    PubMed Central

    Li, Xiaojing; Wang, Xin; Zhao, Qian; Zhang, Yueyong; Zhou, Qixing

    2016-01-01

    The electrical conductivity (EC) of soil is generally measured after soil extraction, so this method cannot represent the in situ EC of soil (e.g., EC of soils with different moisture contents) and therefore lacks comparability in some cases. Using a resistance measurement apparatus converted from a configuration of soil microbial fuel cell, the in situ soil EC was evaluated according to the Ohmic resistance (Rs) measured using electrochemical impedance spectroscopy. The EC of soils with moisture content from 9.1% to 37.5% was calculated according to Rs. A significant positive correlation (R2 = 0.896, p < 0.01) between the soil EC and the moisture content was observed, which demonstrated the feasibility of the approach. This new method can not only represent the actual soil EC, but also does not need any pretreatment. Thus it may be used widely in the measurement of the EC for soils and sediments. PMID:27144567

  5. In Situ Representation of Soil/Sediment Conductivity Using Electrochemical Impedance Spectroscopy.

    PubMed

    Li, Xiaojing; Wang, Xin; Zhao, Qian; Zhang, Yueyong; Zhou, Qixing

    2016-04-30

    The electrical conductivity (EC) of soil is generally measured after soil extraction, so this method cannot represent the in situ EC of soil (e.g., EC of soils with different moisture contents) and therefore lacks comparability in some cases. Using a resistance measurement apparatus converted from a configuration of soil microbial fuel cell, the in situ soil EC was evaluated according to the Ohmic resistance (Rs) measured using electrochemical impedance spectroscopy. The EC of soils with moisture content from 9.1% to 37.5% was calculated according to Rs. A significant positive correlation (R² = 0.896, p < 0.01) between the soil EC and the moisture content was observed, which demonstrated the feasibility of the approach. This new method can not only represent the actual soil EC, but also does not need any pretreatment. Thus it may be used widely in the measurement of the EC for soils and sediments.

  6. External exposure to radionuclides in air, water, and soil

    SciTech Connect

    Eckerman, K.F.; Ryman, J.C.

    1996-05-01

    Federal Guidance Report No. 12 tabulates dose coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, water, and soil. The dose coefficients are intended for use by Federal Agencies in calculating the dose equivalent to organs and tissues of the body.

  7. Soil air CO2 concentration as an integrative parameter of soil structure

    NASA Astrophysics Data System (ADS)

    Ebeling, Corinna; Gaertig, Thorsten; Fründ, Heinz-Christian

    2015-04-01

    The assessment of soil structure is an important but difficult issue and normally takes place in the laboratory. Typical parameters are soil bulk density, porosity, water or air conductivity or gas diffusivity. All methods are time-consuming. The integrative parameter soil air CO2 concentration ([CO2]) can be used to assess soil structure in situ and in a short time. Several studies highlighted that independent of soil respiration, [CO2] in the soil air increases with decreasing soil aeration. Therefore, [CO2] is a useful indicator of soil aeration. Embedded in the German research project RÜWOLA, which focus on soil protection at forest sites, we investigated soil compaction and recovery of soil structure after harvesting. Therefore, we measured soil air CO2 concentrations continuously and in single measurements and compared the results with the measurements of bulk density, porosity and gas diffusivity. Two test areas were investigated: At test area 1 with high natural regeneration potential (clay content approx. 25 % and soil-pH between 5 and 7), solid-state CO2-sensors using NDIR technology were installed in the wheel track of different aged skidding tracks in 5 and 10 cm soil depths. At area 2 (acidic silty loam, soil-pH between 3.5 and 4), CO2-sensors and water-tension sensors (WatermarkR) were installed in 6 cm soil depth. The results show a low variance of [CO2] in the undisturbed soil with a long term mean from May to June 2014 between 0.2 and 0.5 % [CO2] in both areas. In the wheel tracks [CO2] was consistently higher. The long term mean [CO2] in the 8-year-old-wheel track in test area 1 is 5 times higher than in the reference soil and shows a high variation (mean=2.0 %). The 18-year-old wheel track shows a long-term mean of 1.2 % [CO2]. Furthermore, there were strong fluctuations of [CO2] in the wheel tracks corresponding to precipitation and humidity. Similar results were yielded with single measurements during the vegetation period using a portable

  8. Sorption and photolysis studies in soil and sediment of the herbicide napropamide.

    PubMed

    Aguer, J P; Cox, L; Richard, C; Hermosin, M C; Cornejo, J

    2000-11-01

    The influence of soil and sediment composition on sorption and photodegradation of the herbicide napropamide [N,N-diethyl-2-(1-naphthyloxy)propionamide] was investigated. Five soils and one sediment were selected for this study and the clay fractions were obtained by sedimentation. Sorption-desorption was studied by batch equilibration technique and photolysis in a photoreactor emitting within 300-450 nm wavelength with a maximum at 365 nm. Sorption increased with clay content and was not related to organic matter content. High irreversibility of sorption was related to the greater montmorillonite content. The presence of soil or sediment reduced photolysis rate due to screen effect and this process did not depend on solid composition but on particle size distribution. PMID:11069015

  9. Effects of Air Drying on Soil Available Phosphorus in Two Grassland Soils

    NASA Astrophysics Data System (ADS)

    Schaerer, M.; Frossard, E.; Sinaj, S.

    2003-04-01

    Mobilization of P from the soil to ground and surface water is principally determined by the amount of P in the soil and physico-chemical as well as biological processes determining the available P-pool that is in equilibrium with soil solution. Soil available P is commonly estimated on air dry soil using a variety of methods (extraction with water, dilute acids and bases, anion exchange resin, isotopic exchange or infinite sinks). Recently, attempts have been made to use these measurements to define the potential for transport of P from soil to water by overland flow or subsurface flow. The effect of air drying on soil properties in general, and plant nutrient status in particular, have been subject of a number of studies. The main objective of this paper was to evaluate the effect of air-drying on soil properties and available P. For this experiment, grassland soils were sampled on two study sites located on slopes in the watershed of Lake Greifensee, 25 km south-east of Zurich. Both soils (0-4 cm depth) are rich in P with 1.7 and 1.3 g kg-1 total P at site I and site II, respectively. The concentrations on isotopically exchangeable P within 1 minute (E1min, readily available P) for the same depth were also very high, 58 and 27 mg P kg soil-1 for the site I and II, respectively. In the present study both field moist and air dried soil samples were analyzed for microbial P (Pmic), resin extractable P (P_r), isotopically exchangeable P (E1min) and amorphous Al and Fe (Alox, Feox). Generally, the microbial P in field moist soils reached values up to 120 mg P/kg soil, whereas after drying they decreased by 73% in average for both soils. On the contrary to Pmic, available P estimated by different methods strongly increased after drying of the soil samples. The concentration of phosphate ions in the soil solution c_p, E1min and P_r were 4.2, 2.2 and 2 times higher in dry soils than in field moist soils. The increase in available P shows significant semilogarithmic

  10. Modeling of soil erosion and sediment transport in the East River Basin in southern China

    USGS Publications Warehouse

    Wu, Yping; Chen, Ji

    2012-01-01

    Soil erosion is a major global environmental problem that has caused many issues involving land degradation, sedimentation of waterways, ecological degradation, and nonpoint source pollution. Therefore, it is significant to understand the processes of soil erosion and sediment transport along rivers, and this can help identify the erosion prone areas and find potential measures to alleviate the environmental effects. In this study, we investigated soil erosion and identified the most seriously eroded areas in the East River Basin in southern China using a physically-based model, Soil and Water Assessment Tool (SWAT). We also introduced a classical sediment transport method (Zhang) into SWAT and compared it with the built-in Bagnold method in simulating sediment transport process along the river. The derived spatial soil erosion map and land use based erosion levels can explicitly illustrate the identification and prioritization of the critical soil erosion areas in this basin. Our results also indicate that erosion is quite sensitive to soil properties and slope. Comparison of Bagnold and Zhang methods shows that the latter can give an overall better performance especially in tracking the peak and low sediment concentrations along the river. We also found that the East River is mainly characterized by sediment deposition in most of the segments and at most times of a year. Overall, the results presented in this paper can provide decision support for watershed managers about where the best management practices (conservation measures) can be implemented effectively and at low cost. The methods we used in this study can also be of interest in sediment modeling for other basins worldwide.

  11. Correlation of soil and sediment organic matter polarity to aqueous sorption of nonionic compounds

    USGS Publications Warehouse

    Kile, D.E.; Wershaw, R. L.; Chiou, C.T.

    1999-01-01

    Polarities of the soiL/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment sam pies were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (K(oc)) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct assessment of the polarity of SOM that is not possible by elemental analysis. The percent of organic carbon associated with polar functional groups was estimated from the combined fraction of carbohydrate and carboxylamide-ester carbons. A plot of the measured partition coefficients (K(oc)) of carbon tetrachloride (CT) vs. percent polar organic carbon (POC) shows distinctly different populations of soils and sediments as well as a roughly inverse trend among the soil/sediment populations. Plots of K(oc) values for CT against other structural group carbon fractions did not yield distinct populations. The results indicate that the polarity of SOM is a significant factor in accounting for differences in K(oc) between the organic matter in soils and sediments. The alternate direct correlation of the sum of aliphatic and aromatic structural carbons with K(oc) illustrates the influence of nonpolar hydrocarbon on solute partition interaction. Additional elemental analysis data of selected samples further substantiate the effect of the organic matter polarity on the partition efficiency of nonpolar solutes. The separation between soil and sediment samples based on percent POC reflects definite differences of the properties of soil and sediment organic matters that are attributable to diagenesis.Polarities of the soil/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment samples were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (Koc) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct

  12. Soil erosion and causative factors at Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Butterworth, Joel B.

    1988-01-01

    Areas of significant soil erosion and unvegetated road cuts were identified and mapped for Vandenberg Air Force Base. One hundred forty-two eroded areas (most greater than 1.2 ha) and 51 road cuts were identified from recent color infrared aerial photography and ground truthed to determine the severity and causes of erosion. Comparison of the present eroded condition of soils (as shown in the 1986 photography) with that in historical aerial photography indicates that most erosion on the base took place prior to 1928. However, at several sites accelerated rates of erosion and sedimentation may be occurring as soils and parent materials are eroded vertically. The most conspicuous erosion is in the northern part of the base, where severe gully, sheet, and mass movement erosion have occurred in soils and in various sedimentary rocks. Past cultivation practices, compounded by highly erodible soils prone to subsurface piping, are probably the main causes. Improper range management practices following cultivation may have also increased runoff and erosion. Aerial photography from 1986 shows that no appreciable headward erosion or gully sidewall collapse have occurred in this area since 1928.

  13. Erodibility of selected soils and estimates of sediment yields in the San Juan Basin, New Mexico

    USGS Publications Warehouse

    Summer, Rebecca M.

    1981-01-01

    Onsite rainfall-simulation experiments were conducted to derive field-erodibility indexes for rangeland soils and soils disturbed by mining in coal fields of northwestern New Mexico. Mean indexes on rangeland soils range from 0 grams (of detached soil) on dune soil to 121 grams on wash-transport zones. Mean field-erodibility-index values of soils disturbed by mining range from 16 to 32 grams; they can be extrapolted to nearby coal fields where future mining is expected. Because field-erodibility-index data allow differentiation of erodibilities across a variable landscape, these indexes were used to adjust values of K, the erodibility factor of the Universal Soil Loss Equation. Estimates of soil loss and sediment yield were then calculated for a small basin following mining. (USGS)

  14. Relationship between heavy metals in mud sediments and beach soil of the River Nile

    SciTech Connect

    Awadallah, R.M.; Soltan, M.E.; Rashed, M.N.

    1996-08-01

    the chemical partitioning of selected inorganic ions was investigated in mud sediments taken from the bottom of the main stream of the River Nile by means of sediment sampler and beach soil samples collected from seven sectors (three subsamples from each location) between Aswan and Giza (Aswan, Qena, Sohag, Assiut, El Menya, Beni Suef, and Giza). These samples were analyzed by an atomic absorption spectrophotometer. The results showed that iron and lead were found at higher levels in beach soil than in the river sediments at all sites except for iron sediments of Aswan where the region was subjected to volcanic activities in the ancient geological eras (granites,.....etc.). At some sites, some heavy-metal concentrations seemed to be higher in sediment than in beach soil as a result of weathering of beach soil by the effect of wind and currents of water. In other sites, sediment pollution by these metals might be attributed to inputs from industrial effluents and domestic wastewater drained directly into the Nile. Statistical analysis of data shows significant correlation coefficient values (r= up to 0.915) 30 refs., 1 fig., 2 tabs.

  15. An experimental study of rill sediment delivery in purple soil, using the volume-replacement method

    PubMed Central

    Huang, Yuhan; Luo, Banglin; Ding, Linqiao; Gong, Chunming

    2015-01-01

    Experimental studies provide a basis for understanding the mechanisms of rill erosion and can provide estimates for parameter values in physical models simulating the erosion process. In this study, we investigated sediment delivery during rill erosion in purple soil. We used the volume-replacement method to measure the volume of eroded soil and hence estimate the mass of eroded soil. A 12 m artificial rill was divided into the following sections: 0–0.5 m, 0.5–1 m, 1–2 m, 2–3 m, 3–4 m, 4–5 m, 5–6 m, 6–7 m, 7–8 m, 8–10 m, and 10–12 m. Erosion trials were conducted with three flow rates (2 L/min, 4 L/min, and 8 L/min) and five slope gradients (5°, 10°, 15°, 20°, and 25°). The eroded rill sections were refilled with water to measure the eroded volume in each section and subsequently calculate the eroded sediment mass. The cumulative sediment mass was used to compute the sediment concentration along the length of the rill. The results show that purple soil sediment concentration increases with rill length before eventually reaching a maximal value; that is, the rate of increase in sediment concentration is greatest at the rill inlet and then gradually slows. Steeper slopes and higher flow rates result in sediment concentration increasing more rapidly along the rill length and the maximum sediment concentration being reached at an earlier location in the rill. Slope gradient and flow rate both result in an increase in maximal sediment concentration and accumulated eroded amount. However, slope gradient has a greater influence on rill erosion than flow rate. The results and experimental method in this study may provide a reference for future rill-erosion experiments. PMID:26734498

  16. Effects of sedimentation on soil nutrient dynamics in riparian forests.

    PubMed

    Lockaby, B G; Governo, R; Schilling, E; Cavalcanti, G; Hartsfield, C

    2005-01-01

    The influence of sedimentation rates on biogeochemistry of riparian forests was studied near ephemeral streams at Fort Benning, GA. Upper reaches of seven ephemeral streams had received varying rates of sedimentation stemming from erosion along unpaved roadways at the military installation. Two reference catchments were also included in the study. Decomposition of foliar litter, microbial C and N, N mineralization, and arthropod populations were compared within and among catchments. Rates of sedimentation over the past 25 yr ranged from 0 in references to 4.0 cm yr(-1). Decomposition rates declined exponentially with sedimentation rates as low as 0.20 to 0.32 cm yr(-1) and appeared to reach an equilibrium at a sedimentation rate of 0.5 cm yr(-1). Nitrogen mineralization and microbial C and N followed the same trend. Sedimentation had no discernible effect on arthropod populations. These data suggest that biogeochemical cycles may be altered by sedimentation rates that commonly occur in some floodplain forests. PMID:15647569

  17. Bioavailability of chromium in soils and sediments at a former leather tannery site

    SciTech Connect

    Pacquin, P.R.; Di Toro, D.M.; De Rosa, L.; Maiello, J.; Kerrigan, J.

    1995-12-31

    Bioavailability is a fundamental consideration in the equilibrium partitioning method used by EPA to develop sediment quality criteria (SOC). Even so, the bioavailability of metals in soils and sediments is often overlooked in ecological risk assessments for Superfund sites. This paper summarizes field and laboratory data for chromium levels in biota, soil and sediment samples from an abandoned tannery site and presents a method for characterizing the bioavailable fraction of chromium in these media. Chromium levels in soils and sediments at the former tannery site are about 1,000 times higher than levels at control sites (30,000 ppm versus 30 ppm). The elevated chromium levels are due to previously released tannery wastes, which contain high levels of chromium as a result of the tanning process. In contrast to chromium levels in soils and sediments, levels in terrestrial biota (earthworms, vegetation, and meadow voles) and aquatic biota (minnows, crayfish and mayfly nymphs) at the site are only about 2 to 20 times higher than control area samples. Biota:Soil and Biota:Sediment Accumulation Factors (BSAFs, total chromium basis) for the site are about one to five percent of control area BSAFs. This difference indicates that chromium at the site is relatively non-bioavailable. Sequential extraction techniques were used to characterize the manner in which the chromium is bound to soil and sediment at the site. The extraction results are compared with the biota field data and it appears that the exchangeable chromium fraction is indicative of the bioavailable fraction. The implications of these results to a screening level ecological risk assessment are presented.

  18. Disposal of dredged sediments in tropical soils: ecotoxicological evaluation based on bioassays with springtails and enchytraeids.

    PubMed

    Cesar, Ricardo; Natal-da-Luz, Tiago; Bidone, Edison; Castilhos, Zuleica; Polivanov, Helena; Sousa, José Paulo

    2015-02-01

    Metal reference values established in Brazilian legislation for terrestrial disposal of dredged sediments and soil quality were derived for temperate regions. To evaluate the adequacy of such metal reference values to tropical soils, the ecotoxicity of a dredged sediment (from the Guanabara bay, Rio de Janeiro, Brazil) was investigated in two local soils (ferralsol and chernosol) by performing avoidance and reproduction tests using Folsomia candida and Enchytraeus crypticus. Test doses consisted of 0 %, 1.25 %, 2.5 %, 5, 10 %, and 20 %. Total and potentially bioavailable metal concentrations were determined in the test mixtures. Although the chernosol mixtures had the highest total metal concentrations, the influence of the expansive clay minerals (with high ability to adsorb metals) and the high contents of nutrients typical from this type of soils, seem to reduce the ecotoxicity. Collembolan avoidance behavior was the least sensitive endpoint. The lowest sediment doses increased the reproduction of F. candida in ferralsol mixtures. E. crypticus reproduction in the ferralsol mixtures were more pronounced at lower concentrations than in chernosol mixtures. Possibly the low nutrient content of the ferralsols, in connection with the addition of small amounts of sediment, created particular conditions that promoted reproduction of the test species. Data obtained in the ecotoxicological tests may support the establishment of a "safe" ecological dose of dredged sediments to be applied in tropical soils, supporting decision-makers in programs of environmental management. PMID:25223356

  19. Characterization of near-bed sediment transport in air and water by high-speed video

    NASA Astrophysics Data System (ADS)

    Martin, C. S.; Hamm, N. T.; Cushman-Roisin, B.; Dade, W. B.

    2010-12-01

    Near-bed sediment transport comprises a large fraction of the total mass flux of environmental flows, yet is difficult to characterize at fine scales without disturbing the flow. Particle-tracking velocimetry by means of high-speed video has proven to be an effective technique for quantifying particle behavior under this constraint. We present here results of experiments examining: i) the vertical structure of mass and momentum and ii) initial properties of particle trajectories within a layer of sediment transport immediately above a bed of loose grains in channel flows. Observations were conducted in both air and water of test particles with the density of quartz and with median diameters that ranged from 30 µm to 600 µm. Analysis of such a wide range of sediment transport conditions by the same method permits an evaluation of the fundamental structure of the near-bed sediment transport layer, including particle concentration and particle velocity. With appropriate normalization, self-consistent structure is identified for all particles in air, medium sand in water, and fine sand and silt in water. The integral values by which the data were normalized are found to be consistent with the relevant physical properties of the sediment transporting flow. This study advances the use of high-speed videography as a method by which to investigate the detailed mechanics of particle motion in a near-bed boundary layer, which in turn, can provide boundary conditions used for modeling sediment transport in a variety of applications.

  20. Pesticide pollution of soil, water and air in Delhi area, India.

    PubMed

    Pillai, M K

    1986-11-01

    In India organochlorine insecticides such as DDT and HCH constitute more than 70% of the pesticides used at present. Its continued use has given interest to monitor for the last few years the extent of organochlorine insecticide residues in soil, water, air and rain water in Delhi area. Out of the 50 samples each of soil and earthworms collected from different parts 48 samples showed that soil and earthworms contained 0-2.61 and 0-37.74 mg Kg-1 of total DDT residues respectively. The area near the vicinity of the DDT factory showed high levels of DDT residues. A two-year survey of the Yamuna river in Delhi showed that water contained an average of 0.24 ug L-1 and the bottom sediment had 0.24 mg Kg-1 of total DDT residues. The fishes collected from the Yamuna river showed very high bioaccumulation of DDT residues. The air and rainwater samples monitored from 3 different areas for two years indicated that DDT was more near the DDT factory area while HCH was more near a commercial complex. These results indicate that the overall organochlorine-residue levels in Delhi is not alarming. It probably indicates that DDT and HCH are more rapidly dissipated and degraded in a tropical country like India. PMID:3810135

  1. Pesticide pollution of soil, water and air in Delhi area, India.

    PubMed

    Pillai, M K

    1986-11-01

    In India organochlorine insecticides such as DDT and HCH constitute more than 70% of the pesticides used at present. Its continued use has given interest to monitor for the last few years the extent of organochlorine insecticide residues in soil, water, air and rain water in Delhi area. Out of the 50 samples each of soil and earthworms collected from different parts 48 samples showed that soil and earthworms contained 0-2.61 and 0-37.74 mg Kg-1 of total DDT residues respectively. The area near the vicinity of the DDT factory showed high levels of DDT residues. A two-year survey of the Yamuna river in Delhi showed that water contained an average of 0.24 ug L-1 and the bottom sediment had 0.24 mg Kg-1 of total DDT residues. The fishes collected from the Yamuna river showed very high bioaccumulation of DDT residues. The air and rainwater samples monitored from 3 different areas for two years indicated that DDT was more near the DDT factory area while HCH was more near a commercial complex. These results indicate that the overall organochlorine-residue levels in Delhi is not alarming. It probably indicates that DDT and HCH are more rapidly dissipated and degraded in a tropical country like India.

  2. Sediment Dynamics Within Buffer Zone and Sinkhole Splay Areas Under Extreme Soil Disturbance Conditions.

    PubMed

    Schoonover, Jon E; Crim, Jackie F; Williard, Karl W J; Groninger, John W; Zaczek, James J; Pattumma, Klairoong

    2015-09-01

    Sedimentation dynamics were assessed in sinkholes within training areas at Ft. Knox Military Installation, a karst landscape subjected to decades of tracked vehicle use and extreme soil disturbance. Sinkholes sampled were sediment-laden and behaved as intermittent ponds. Dendrogeomorphic analyses were conducted using willow trees (Salix spp.) located around the edge of 18 sinkholes to estimate historical sedimentation rates, and buried bottles were installed in 20 sinkholes at the center, outer edge, and at the midpoint between the center and edge to estimate annual sedimentation rates. Sedimentation data were coupled with vegetation characteristics of sinkhole buffers to determine relationships among these variables. The dendrogeomorphic method estimated an average accumulation rate of 1.27 cm year(-1) translating to a sediment loss rate of 46.1 metric ton year(-1) from the training areas. However, sediment export to sinkholes was estimated to be much greater (118.6 metric ton year(-1)) via the bottle method. These data suggest that the latter method provided a more accurate estimate since accumulation was greater in the center of sinkholes compared to the periphery where dendrogeomorphic data were collected. Vegetation data were not tightly correlated with sedimentation rates, suggesting that further research is needed to identify a viable proxy for direct measures of sediment accumulation in this extreme deposition environment. Mitigation activities for the sinkholes at Ft. Knox's tank training area, and other heavily disturbed karst environments where extreme sedimentation exists, should consider focusing on flow path and splay area management.

  3. Sediment Dynamics Within Buffer Zone and Sinkhole Splay Areas Under Extreme Soil Disturbance Conditions

    NASA Astrophysics Data System (ADS)

    Schoonover, Jon E.; Crim, Jackie F.; Williard, Karl W. J.; Groninger, John W.; Zaczek, James J.; Pattumma, Klairoong

    2015-09-01

    Sedimentation dynamics were assessed in sinkholes within training areas at Ft. Knox Military Installation, a karst landscape subjected to decades of tracked vehicle use and extreme soil disturbance. Sinkholes sampled were sediment-laden and behaved as intermittent ponds. Dendrogeomorphic analyses were conducted using willow trees ( Salix spp.) located around the edge of 18 sinkholes to estimate historical sedimentation rates, and buried bottles were installed in 20 sinkholes at the center, outer edge, and at the midpoint between the center and edge to estimate annual sedimentation rates. Sedimentation data were coupled with vegetation characteristics of sinkhole buffers to determine relationships among these variables. The dendrogeomorphic method estimated an average accumulation rate of 1.27 cm year-1 translating to a sediment loss rate of 46.1 metric ton year-1 from the training areas. However, sediment export to sinkholes was estimated to be much greater (118.6 metric ton year-1) via the bottle method. These data suggest that the latter method provided a more accurate estimate since accumulation was greater in the center of sinkholes compared to the periphery where dendrogeomorphic data were collected. Vegetation data were not tightly correlated with sedimentation rates, suggesting that further research is needed to identify a viable proxy for direct measures of sediment accumulation in this extreme deposition environment. Mitigation activities for the sinkholes at Ft. Knox's tank training area, and other heavily disturbed karst environments where extreme sedimentation exists, should consider focusing on flow path and splay area management.

  4. Assessment of environmentally persistent free radicals in soils and sediments from three Superfund sites.

    PubMed

    dela Cruz, Albert Leo N; Cook, Robert L; Dellinger, Barry; Lomnicki, Slawomir M; Donnelly, Kirby C; Kelley, Matthew A; Cosgriff, David

    2014-01-01

    We previously reported the presence of environmentally persistent free radicals (EPFRs) in pentachlorophenol (PCP) contaminated soils at a closed wood treatment facility site in Georgia. The reported EPFRs were pentachlorophenoxyl radicals formed on soils under ambient conditions via electron transfer from PCP to electron acceptors in the soil. In this study, we present results for soil and sediment samples from additional Superfund sites in Montana and Washington. Paramagnetic centers associated with different chemical environments were characterized by distinct g-factors and line widths (ΔHp-p). EPFR concentrations in contaminated samples were ~30×, ~12×, and ~2× higher than background samples at the Georgia, Montana, and Washington sites, respectively. EPR signals in the Montana contaminated soils were very similar to those previously observed for pentachlorophenol contaminated soils at the Georgia site, i.e., g = 2.00300 and ΔHp-p = 6.0 G, whereas signals in the Washington sediment samples were similar to those previously observed for other PAH contaminated soils, i.e., g = 2.00270 and ΔHp-p = 9.0 G. Total carbon content measurements exhibited direct correlation with EPFR concentration. The presence of radicals in sites contaminated a decade to a century ago suggests continuous formation of EPFRs from molecular contaminants in the soil and sediment. PMID:24244947

  5. Assessment of Environmentally Persistent Free Radicals in Soils and Sediments from Three Superfund Sites

    PubMed Central

    dela Cruz, Albert Leo N.; Cook, Robert L.; Dellinger, Barry; Lomnicki, Slawomir M.; Donnelly, Kirby C.; Kelley, Matthew A.; Cosgriff, David

    2014-01-01

    We previously reported the presence of environmentally persistent free radicals (EPFRs) in pentachlorophenol (PCP) contaminated soils at a closed wood treatment facility site in Georgia. The reported EPFRs were pentachlorophenoxyl radicals formed on soils under ambient conditions via electron transfer from PCP to electron acceptors in the soil. In this study, we present results for soil and sediment samples from additional Superfund sites in Montana and Washington. Paramagnetic centers associated with different chemical environments were characterized by distinct g-factors and line widths (ΔHp-p). EPFR concentrations in contaminated samples were ~30x, ~12x, and ~2x higher than background samples at the Georgia, Montana, and Washington sites, respectively. EPR signals in the Montana contaminated soils were very similar to those previously observed for pentachlorophenol contaminated soils at the Georgia site, i.e., g = 2.00300 and ΔHp-p = 6.0 G, whereas signals in the Washington sediment samples were similar to those previously observed for other PAH contaminated soils, i.e., g = 2.00270 and ΔHp-p = 9.0G. Total carbon content measurements exhibited direct correlation with EPFR concentration. The presence of radicals in sites contaminated a decade to a century ago suggests continuous formation of EPFRs from molecular contaminants in the soil and sediment. PMID:24244947

  6. The role of climate in balancing soil production and sediment yield in New Zealand

    NASA Astrophysics Data System (ADS)

    Norton, K. P.

    2013-12-01

    New Zealand hosts some of the highest specific sediment yields on the planet reaching up to nearly 30,000 t km-2 yr-1. Sediment yields measure the export of sediment from a basin and give an indication of erosion from hillslopes. In New Zealand high sediment yields correlate with high annual precipitation and high rates of tectonic strain (Hicks et al., 1996). It is, however, unclear how soil production keeps pace with such extreme erosion. Here, this question is investigated by modelling soil production as a function of local climate parameters. Two simple models for building climate into soil production are through effective energy and mass transfer, EEMT, (Rasmussen and Tabor, 2007) and primary chemical weathering. When applied to ~30 year climate data, these models highlight the variability of potential soil production across New Zealand. Due partially to high annual rainfall, some of the fastest erosion rates on the west coast of the South Island are nearly in balance with soil production. In other regions such as the east coast of the North Island, hotspots exist where annual sediment yields exceed reasonable soil production rates such that additional mechanisms must operate to generate sediment and make up this deficit. Globally, precipitation tends to increase and temperature decreases with increasing elevation. In New Zealand, increasing elevations also roughly correlate with an increase in mean basin slope angle and the percent of a basin at >30° slopes. As a result, modelled soil production also tends to increase with increasing mean basin slope angle. This correlation occurs independent of erosion feedbacks on the modelled soil production rates. This relationship presents an intriguing scenario in which the topography of the mountain range may be maintained by climate through variations in soil production. Even with rapid modelled soil production at high precipitation rates and/or high temperatures and/or high temperatures, many basins cannot keep pace

  7. Mercury Fractionation in Superficial Sediment and Paddy Soil Samples from Tianjin, Northern China.

    PubMed

    Wu, Chao; Zhang, Zhaoji; Fei, Yuhong; Wu, Guoqing; Qian, Yong

    2016-08-01

    Sediment and soil samples from the Beitang River (BR) and the Haihe River (HR) in Tianjin were analyzed to investigate the extent of mercury contamination. The results show that total mercury (THg) contents in the BR and HR sediments were 2241 ± 1024 and 653 ± 450 ng g(-1), and THg in rice paddy soils were 907 ± 345 and 328 ± 286 ng g(-1), respectively. Industrial and domestic sewage were regarded as the main sources of mercury in the two river basins. Sediment-bound mercury in the BR and the HR were found to be predominantly associated with the organic-bound fraction (55 %) and residual fraction and (54 %), while soil-bound mercury was mainly in organic-bound fraction in paddy soils (61 % and 57 %, respectively). The availability of this element (soluble and exchangeable and specifically sorbed fraction) seemed restricted, but significantly higher in the paddy soils than in sediments. Higher soluble and exchangeable, specifically sorbed fraction and organic-bound fraction may promote the higher toxic methylmercury and bioavailable fraction formation in the soils during the rice cultivation. PMID:27283074

  8. Cadmium contamination in Tianjin agricultural soils and sediments: relative importance of atmospheric deposition from coal combustion.

    PubMed

    Wu, Guanghong; Yang, Cancan; Guo, Lan; Wang, Zhongliang

    2013-06-01

    Cadmium (Cd) in coal, fly ash, slag, atmospheric deposition, soils and sediments collected from Tianjin, northern China, were measured to provide baseline information and determine possible Cd sources and potential risk. The concentrations of Cd in coal, fly ash and atmospheric deposition were much higher than the soil background values. Fallout from coal-fired thermal power plants, heating boilers and industrial furnaces has increased the Cd concentration in soils and sediments in Tianjin. The concentrations of Cd in soils of suburban areas were significantly higher than in rural areas, suggesting that coal burning in Tianjin may have an important impact on the local physical environment. Cd from coal combustion is readily mobilized in soils. It is soluble and can form aqueous complexes and permeate river sediments. The high proportion of mobile Cd affects the migration of Cd in soils and sediments, which may pose an environmental threat in Tianjin due to the exposure to Cd and Cd compounds via the food chain. This study may provide a window for understanding and tracing sources of Cd in the local environment and the risk associated with Cd bioaccessibility.

  9. Mercury Fractionation in Superficial Sediment and Paddy Soil Samples from Tianjin, Northern China.

    PubMed

    Wu, Chao; Zhang, Zhaoji; Fei, Yuhong; Wu, Guoqing; Qian, Yong

    2016-08-01

    Sediment and soil samples from the Beitang River (BR) and the Haihe River (HR) in Tianjin were analyzed to investigate the extent of mercury contamination. The results show that total mercury (THg) contents in the BR and HR sediments were 2241 ± 1024 and 653 ± 450 ng g(-1), and THg in rice paddy soils were 907 ± 345 and 328 ± 286 ng g(-1), respectively. Industrial and domestic sewage were regarded as the main sources of mercury in the two river basins. Sediment-bound mercury in the BR and the HR were found to be predominantly associated with the organic-bound fraction (55 %) and residual fraction and (54 %), while soil-bound mercury was mainly in organic-bound fraction in paddy soils (61 % and 57 %, respectively). The availability of this element (soluble and exchangeable and specifically sorbed fraction) seemed restricted, but significantly higher in the paddy soils than in sediments. Higher soluble and exchangeable, specifically sorbed fraction and organic-bound fraction may promote the higher toxic methylmercury and bioavailable fraction formation in the soils during the rice cultivation.

  10. Sorption of radium-226 from oil-production brine by sediments and soils

    USGS Publications Warehouse

    Landa, E.R.; Reid, D.F.

    1983-01-01

    The sorption of226Ra from oil-production brine by soils and sediments was investigated. Sorption was rapid, and the percentage sorbed increased with brine dilution. Greatest removals of226Ra from sediments in the laboratory occurred with alkaline DTPA, HCl, and BaCl2, with lesser removals using CaCl2 and NaCl solutions. Digestion of sediments with NaOCl indicates that most of the native and sorbed226Ra is associated with the mineral rather than organic fraction of the sediments. Correlation analysis based on 14 soils indicates that the retention of226Ra may involve precipitation reactions associated with sulfate-bearing minerals, as well as ion-exchange reactions with the clay mineral fractions of surficial earth materials. ?? 1982 Springer-Verlag New York Inc.

  11. STANDARDS CONTROLLING AIR EMISSIONS FOR THE SOIL DESICCATION PILOT TEST

    SciTech Connect

    BENECKE MW

    2010-09-08

    This air emissions document supports implementation of the Treatability Test Plan for Soil Desiccation as outlined in the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau (DOE/RL-2007-56). Treatability testing supports evaluation of remedial technologies for technetium-99 (Tc-99) contamination in the vadose zone at sites such as the BC Cribs and Trenches. Soil desiccation has been selected as the first technology for testing because it has been recommended as a promising technology in previous Hanford Site technology evaluations and because testing of soil desiccation will provide useful information to enhance evaluation of other technologies, in particular gas-phase remediation technologies. A soil desiccation pilot test (SDPT) will evaluate the desiccation process (e.g., how the targeted interval is dried) and the long-term performance for mitigation of contaminant transport. The SDPT will dry out a moist zone contaminated by Tc-99 and nitrate that has been detected at Well 299-E13-62 (Borehole C5923). This air emissions document applies to the activities to be completed to conduct the SDPT in the 200-BC-1 operable unit located in the 200 East Area of the Hanford Site. Well 299-E13-62 is planned to be used as an injection well. This well is located between and approximately equidistant from cribs 216-B-16, 216-B-17, 216-B-18. and 216-B-19. Nitrogen gas will be pumped at approximately 300 ft{sup 3}/min into the 299-EI3-62 injection well, located approximately 12 m (39 ft) away from extraction well 299-EI3-65. The soil gas extraction rate will be approximately 150 ft{sup 3}/min. The SDPT will be conducted continuously over a period of approximately six months. The purpose of the test is to evaluate soil desiccation as a potential remedy for protecting groundwater. A conceptual depiction is provided in Figure 1. The soil desiccation process will physically dry, or evaporate, some of the water from the moist zone of interest. As such, it is

  12. Effect of soil surface conditions on runoff velocity and sediment mean aggregate diameter

    NASA Astrophysics Data System (ADS)

    César Ramos, Júlio; Bertol, Ildegardis; Paz González, Antonio; de Souza Werner, Romeu; Marioti, Juliana; Henrique Bandeira, Douglas; Andrighetti Leolatto, Lidiane

    2013-04-01

    Soil cover and soil management are the factors that most influence soil erosion by water, because they directly affect soil surface roughness and surface cover. The main effect of soil cover by crop residues consists in dissipation of kinetic energy of raindrops and also partly kinetic energy of runoff, so that the soil disaggregation is considerably reduced but, in addition, soil cover captures detached soil particles, retains water on its surface and decreases runoff volume and velocity. In turn, soil surface roughness, influences soil surface water storage and infiltration and also runoff volume and velocity, sediment retention and subsequently water and sediment losses. Based on the above rationale, we performed a field experiment to assess the influence of soil cover and soil surface roughness on decay of runoff velocity as well as on mean diameter of transported sediments (D50 index). The following treatments were evaluated: SRR) residues of Italian ryegrass (Lolium multiflorum) on a smooth soil surfcace, SRV) residues of common vetch (Vicia sativa) on a smooth soil surface, SSR) scarification after cultivation of Italian ryegrass resulting in a rough surface, SSV) scarification after cultivation of common vetch resulting in a rough surface, and SBS) scarified bare soil with high roughness as a control. The field experiments was performed on an Inceptisol in South Brazil under simulated rainfall conditions during 2012. Experimental plots were 11 m long and 3.5 m wide with an area of 38.5 m2. Six successive simulated rainfall tests were applied using a rotating-boom rain simulator. During each test, rain intensity was 60 mmhr-1, whereas rain duration was 90 minutes. Runoff velocity showed no significant differences between cultivated treatments. However, when compared to bare soil treatment, SBS (0.178 m s-1) and irrespective of the presence of surface crop residues or scarification operations, cultivated soil treatments significantly reduced runoff velocity

  13. Levels of glyphosate in surface waters, sediments and soils associated with direct sowing soybean cultivation in north pampasic region of Argentina.

    PubMed

    Peruzzo, Pablo J; Porta, Atilio A; Ronco, Alicia E

    2008-11-01

    Levels of glyphosate were determined in water, soil and sediment samples from a transgenic soybean cultivation area located near to tributaries streams of the Pergamino-Arrecifes system in the north of the Province of Buenos Aires, Argentina. Field work took into account both the pesticide application and the rains occurring after applications. The pesticide was analysed by HPLC-UV detection, previous derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl). In addition, SoilFug multimedia model was used to analyse the environmental distribution of the pesticides. In the field, levels of glyphosate in waters ranged from 0.10 to 0.70 mg/L, while in sediments and soils values were between 0.5 and 5.0 mg/Kg. Temporal variation of glyphosate levels depended directly on the time of application and the rain events. The results obtained from the application of the model are in accordance with the values found in the field.

  14. Preliminary study on detection sediment contamination in soil affected by the Indian Ocean giant tsunami 2004 in Aceh, Indonesia using laser-induced breakdown spectroscopy (LIBS)

    NASA Astrophysics Data System (ADS)

    Idris, Nasrullah; Ramli, Muliadi; Hedwig, Rinda; Lie, Zener Sukra; Kurniawan, Koo Hendrik

    2016-03-01

    This work is intended to asses the capability of LIBS for the detection of the tsunami sediment contamination in soil. LIBS apparatus used in this work consist of a laser system and an optical multichannel analyzer (OMA) system. The soil sample was collected from in Banda Aceh City, Aceh, Indonesia, the most affected region by the giant Indian Ocean tsunami 2004. The laser beam was focused onto surface of the soil pellet using a focusing lens to produce luminous plasma. The experiment was conducted under air as surrounding gas at 1 atmosphere. The emission spectral lines from the plasma were detected by the OMA system. It was found that metal including heavy metals can surely be detected, thus implying the potent of LIBS technique as a fast screening tools of tsunami sediment contamination.

  15. Extraction of amino acids from soils and sediments with superheated water

    NASA Technical Reports Server (NTRS)

    Cheng, C. N.; Ponnamperuma, C.

    1974-01-01

    A method of extraction for amino acids from soils and sediments involving superheated water has been investigated. About 75-97 per cent of the amino acids contained in four soils of a soil profile from Illinois were extracted by this method. Deep penetration of water into soil aggregates and partial hydrolysis of peptide bonds during this extraction by water at high temperature are likely mechanisms responsible for the release of amino acids from samples. This extraction method does not require subsequent desalting treatments when analyses are carried out with an ion-exchange amino acid analyzer.

  16. Hillslope sediment and soil carbon transport: can we model their movement?

    NASA Astrophysics Data System (ADS)

    Hancock, Greg; Kunkel, Veikko; Dever, Chris; Braggins, Matthew; Willgoose, Garry

    2016-04-01

    Quantifying and predicting the movement of hillslope sediment and soil organic carbon (SOC) is of huge scientific, agronomic and economic benefit. In particular, the movement and fate of SOC has attracted considerable recent attention. However, the reliable modelling and prediction of sediment and SOC movement has proved elusive. Here we examine the movement of sediment and SOC along a grazing hillslope in south-eastern Australia. The slope is linear, uniformly managed and has consistent vegetation (grassland). We quantify sediment and SOC transport using the environmental tracer 137-Ceasium. However, here we collect field samples using the conventional soil cores but also shallow samples to quantify the dynamics of the near surface. We also model the movement of sediment and SOC using a numerically based soil erosion and landscape evolution model. Our results show that the hillslope is erosional which is supported by field observation. However, there was no relationship between SOC and 137-Caesium suggesting that SOC and their movement and fate are not related. Significant relationships were observed between soil texture and SOC for the near surface but not for the deeper cores suggesting any movement and fate of SOC is more controlled by soil particle size at the near surface. The SIBERIA sediment transport model was calibrated and run for the site. Comparing the field derived erosion and SOC data with model prediction found no significant relationship. However, the numerical model was able to predict the cyclic pattern of 137-Ceasium and SOC as well as overall trends. Our findings demonstrate that the movement and fate of sediment and SOC is complex.

  17. Water and sediment dynamics in a small Mediterranean cultivated catchment under cracking soils

    NASA Astrophysics Data System (ADS)

    Inoubli, Nesrine; Raclot, Damien; Moussa, Roger; Habaieb, Hamadi; Le Bissonnais, Yves

    2016-04-01

    Shrink-swell soils, such as those in a Mediterranean climate regime, can cause changes in terms of hydrological and erosive responses due to the changing soil water storage conditions. Only a limited number of long-term studies have focused on the impacts on both hydrological and erosive responses and their interactions in an agricultural environment. In this context, this study aims to document the dynamics of cracks, runoff and soil erosion within a small Mediterranean cultivated catchment and to quantify the influence of crack processes on the water and sediment supplied to a reservoir located at the catchment outlet. Detailed monitoring of the presence of topsoil cracks was conducted within the Kamech catchment (ORE OMERE, Tunisia), and runoff and suspended sediment loads were continuously measured over a long period of time (2005-2012) at the outlets of a field (1.32 ha) and a catchment (263 ha). Analysis of the data showed that topsoil cracks were open approximately half of the year and that the rainfall regime and water table level conditions locally control the seasonal cracking dynamics. Topsoil cracks appeared to seriously affect the generation of runoff and sediment concentrations and, consequently, sediment yields, with similar dynamics observed at the field and catchment outlets. A similar time lag in the seasonality between water and sediment delivery was observed at these two scales: although the runoff rates were globally low during the presence of topsoil cracks, most sediment transport occurred during this period associated with very high sediment concentrations. This study underlines the importance of a good prediction of runoff during the presence of cracks for reservoir siltation considerations. In this context, the prediction of cracking effects on runoff and soil erosion is a key factor for the development of effective soil and water management strategies and downstream reservoir preservation.

  18. Sediments deposition due to soil erosion in the watershed region of Mangla dam.

    PubMed

    Butt, Mohsin Jamil; Mahmood, Rashed; Waqas, Ahmad

    2011-10-01

    Soil erosion is the most important reason of sedimentation load of water reservoirs in the world. In Pakistan, Mangla dam is one of the most important water reservoirs used for the production of electricity and for the supply of water for irrigation purposes. However, the capacity of Mangla dam reservoir has reduced by more than 20% since its construction. This study highlights the impact of rainfall on soil erosion and consequently on sedimentation deposition in Mangla dam reservoir. Sedimentation, annual rainfall, and normal rainfall data of 39 years were used in this study. Shuttle Radar Topographic Mission data were used to calculate the total drainage area of the Mangla watershed region. The sedimentation data of Mangla reservoir from 1967 to 2005 were retrieved from Water and Power Development Authority in Pakistan. The meteorological observatories in the Mangla watershed region are identified. Annual rainfall data from 1967 to 2005 for the meteorological observatories in the Mangla watershed regions were retrieved from Pakistan Meteorological Department (PMD). In addition, normal rainfall data for the years 1949 to 1978 and for the years 1979 to 2008 were also retrieved from PMD. The impact of annual rainfall is observed on sedimentation load in Mangla dam. The correlation coefficient between annual rainfall and sedimentation load is 0.94. This study shows that with an increase in rainfall, the soil erosion of the area increases which subsequently is responsible for the increase in the rate of sedimentation load in Mangla dam. This study further demonstrates that better soil management can reduce the sedimentation load in the Mangla reservoir.

  19. Suspended sediment source areas and future climate impact on soil erosion and sediment yield in a New York City water supply watershed, USA

    NASA Astrophysics Data System (ADS)

    Mukundan, Rajith; Pradhanang, Soni M.; Schneiderman, Elliot M.; Pierson, Donald C.; Anandhi, Aavudai; Zion, Mark S.; Matonse, Adão H.; Lounsbury, David G.; Steenhuis, Tammo S.

    2013-02-01

    High suspended sediment loads and the resulting turbidity can impact the use of surface waters for water supply and other designated uses. Changes in fluvial sediment loads influence material fluxes, aquatic geochemistry, water quality, channel morphology, and aquatic habitats. Therefore, quantifying spatial and temporal patterns in sediment loads is important both for understanding and predicting soil erosion and sediment transport processes as well as watershed-scale management of sediment and associated pollutants. A case study from the 891 km2 Cannonsville watershed, one of the major watersheds in the New York City water supply system is presented. The objective of this study was to apply Soil and Water Assessment Tool-Water Balance (SWAT-WB), a physically based semi-distributed model to identify suspended sediment generating source areas under current conditions and to simulate potential climate change impacts on soil erosion and suspended sediment yield in the study watershed for a set of future climate scenarios representative of the period 2081-2100. Future scenarios developed using nine global climate model (GCM) simulations indicate a sharp increase in the annual rates of soil erosion although a similar result in sediment yield at the watershed outlet was not evident. Future climate related changes in soil erosion and sediment yield appeared more significant in the winter due to a shift in the timing of snowmelt and also due to a decrease in the proportion of precipitation received as snow. Although an increase in future summer precipitation was predicted, soil erosion and sediment yield appeared to decrease owing to an increase in soil moisture deficit and a decrease in water yield due to increased evapotranspiration.

  20. Trace-metal and organic constituent concentrations in bed sediment at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas—Comparisons to sediment-quality guidelines and indications for timing of exposure

    USGS Publications Warehouse

    Justus, B.G.; Hays, Phillip D.; Hart, Rheannon M.

    2015-09-16

    Regarding highest concentrations and associated timing of exposure, trace metals analyzed in the sediment core seem to indicate three fairly distinct exposure patterns. For 11 trace metals that had the highest concentration measured in the shallowest and most recently deposited sediment, the most likely explanation is recent exposure by anthropogenic activities. Most of the 11 trace metals with highest concentrations in shallow sediment are relatively innocuous; however, arsenic, copper, selenium, and zinc are among the U.S. Environmental Protection Agency’s 126 priority pollutants. For three trace metals (cadmium, lead, and mercury), for which concentrations were highest in sediments that were 16–20 centimeters down the core, it is likely that a source associated with those contaminants during the period when those sediments were deposited, was reduced or eliminated. The eight remaining trace metals, for which concentrations were highest in sediments that were just below the prereservoir surface, likely had sources that were eliminated soon after lake construction or occurred at relatively high background concentrations in soils in the area around Little Rock Air Force Base.

  1. Herbicide monitoring in soil, runoff waters and sediments in an olive orchard.

    PubMed

    Calderon, Maria Jesus; De Luna, Elena; Gomez, Jose Alfonso; Hermosin, M Carmen

    2016-11-01

    Occurrences of surface water contamination by herbicides in areas where olive orchards are established reveal a need to understand soil processes affecting herbicide fate at field scale for this popular Mediterranean crop. A monitoring study with two herbicides (terbuthylazine and oxyfluorfen) in the first 2cm of soil, runoff waters, and sediments, was carried out after under natural rainfall conditions following winter herbicide application. At the end of the 107day field experiment, no residues of the soil applied terbuthylazine were recovered, whereas 42% of the oxyfluorfen applied remained in the top soil. Very low levels of both herbicides were measured in runoff waters; however, concentrations were slightly higher for terbuthylazine (0.53% of applied) than for oxyfluorfen (0.03% of applied), relating to their respective water solubilities. Congruent with soil residue data, 38.15% of the applied oxyfluorfen was found in runoff-sediment, compared to only 0.46% for terbuthylazine. Accordingly, the herbicide soil distribution coefficients measured within runoff field tanks was much greater for oxyfluorfen (Kd=3098) than for terbuthylazine (Kd=1.57). The herbicide oxyfluorfen is co-transported with sediment in runoff, remaining trapped and/or adsorbed to soil particle aggregates, due in part to its low water solubility. In contrast, terbuthylazine soil dissipation may be associated more so with leaching processes, favored by its high water solubility, low sorption, and slow degradation. By comparing these two herbicides, our results reaffirm the importance of herbicide physico-chemical properties in dictating their behavior in soil and also suggest that herbicides with low solubility, as seen in the case oxyfluorfen, remain susceptible to offsite transport associated with sediments. PMID:27351146

  2. Delineation of Hydrocarbon Contamination of Soils and Sediments With Environmental Magnetic Methods: Laboratory and Field Studies

    NASA Astrophysics Data System (ADS)

    Rijal, M. L.; Appel, E.; Porsch, K.; Kappler, A.; Blaha, U.; Petrovsky, E.

    2008-12-01

    Hydrocarbon contamination of soils and sediments is a worldwide environmental problem. The present research focuses on the study of magnetic properties of hydrocarbon contaminated soils and sediments using environmental magnetic methods both on field sites as well as in laboratory batch experiments. The main objectives of this research are i) to determine a possible application of magnetic proxies for the delineation of organic contamination in soils and sediments and ii) to examine the role of bacteria in changing soil magnetic properties after hydrocarbon contamination. A former oil field and a former military site which are heavily contaminated with hydrocarbons were studied. Additionally, three different types of natural clean soils were investigated in laboratory experiments by simulating hydrocarbon contamination in sterile and microbial active setups. Magnetic properties, soil properties, iron bioavailability, iron redox state and hydrocarbon content of samples were measured. Additionally, magnetic susceptibility (MS) was monitored weekly in laboratory batch set-ups during several months. Results from the field sites showed that there is an increase of MS and a good correlation between MS and hydrocarbon content. A weekly monitored MS result from the laboratory study clearly indicated~~10% change (increase as well as decrease) of initial MS of respective soils only in microbial active set-ups with saturation after a few weeks of experimental period. This depicts that there is a change of MS caused by microbial iron mineral transformation in presence of hydrocarbon contamination in soils. The results from the field study demonstrate that magnetic proxies can be used to localize hydrocarbon contamination. However, more field sites with hydrocarbon contaminated soils and sediments need to be investigated by using environmental magnetic methods for better understanding the factors driving such changes in magnetic properties.

  3. Mechanisms of soil organic matter stabilization in sediments eroded from small Sierra Nevada catchments

    NASA Astrophysics Data System (ADS)

    Stacy, E.; Hart, S. C.; Hunsaker, C. T.; Johnson, D.; Berhe, A.

    2011-12-01

    Lateral redistribution of soil and associated soil organic matter (SOM) by soil erosion imposes significant controls on SOM dynamics within the eroding watershed, and the overall carbon (C) sequestration potential of the terrestrial biosphere. For sediments exported from eroding watersheds, biochemical composition is a function of SOM in the eroding slope profiles, the type of erosion, duration of transport, and the intensity of decomposition that occurs during transport. Eroded SOM stability, including its molecular architecture and associations with soil minerals, influences complex decomposition dynamics involving microbial activity and abiotic factors during transit and after deposition. Sediment traps located at the point where the first-order stream leaves the watershed provide insight into the material removed by these nearly ephemeral streams before the sediment passes into a larger adjacent watershed. This study investigates the variability in amount and composition of SOM eroded from eight first-order watersheds in the mixed-conifer zone of the Sierra National Forest in the Kings River Experimental Watershed. These watersheds range in size from 48.7 to 650 ha, and have predominately western aspects and granitic bedrock. We are determining the interannual variation in the biochemical composition and stability of SOM of the annual sediment load, and how it relates to the composition of the upslope soil in the watershed. Previous work indicates that the dry weight of sediment transported by the streams may vary by more than two orders of magnitude between years and between watersheds (when normalized to kg/ha; Eagan et al. 2004). Our preliminary results show that the carbon to nitrogen (C:N) ratio of the sediment is less variable between years and watersheds, and is similar to the C:N ratio of surface soils from upslope positions. High concentrations of particulate organic matter in the sediment contribute to higher C concentrations in the sediments than in

  4. Evaluation of in situ capping with clean soils to control phosphate release from sediments.

    PubMed

    Xu, Di; Ding, Shiming; Sun, Qin; Zhong, Jicheng; Wu, Wei; Jia, Fei

    2012-11-01

    Evaluation of in situ capping with clean soils to control phosphate release from the sediments of a eutrophic bay in Lake Taihu was performed after 18 months of capping. The concentrations of dissolved reactive phosphate (DRP) in pore waters and DRP resupply from native sediments and capped sediments were determined using high-resolution dialysis (HR-Peeper) and a Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique. The adsorption isotherm of these sediments was further investigated using a modified Langmuir model. The results showed low concentrations of DRP in pore waters with a low resupply from the sediments for sustaining pore water DRP concentration after capping. The calculated flux to the overlying water following the capping treatment was approximately half of that for the native sediments, implying that the capping reduced the release of phosphate from the sediments. The low resupply of the sediments after capping was further demonstrated by larger partitioning coefficient (K(p)) values and greater adsorption capacity (Q(max)) values, while zero equilibrium concentrations (EPC(0)s) were similar to those in native sediments. The larger K(p) and Q(max) were attributed to higher active Fe and Al introduced by the capping, indicating that the binding of phosphate onto the active Fe and Al played a critical role in reducing the internal loading of phosphorous.

  5. Microbial degradation of hydrochlorofluorocarbons (CHCl2F and CHCl2CF3) in soils and sediments.

    PubMed Central

    Oremland, R S; Lonergan, D J; Culbertson, C W; Lovley, D R

    1996-01-01

    The ability of microorganisms to degrade trace levels of the hydrochlorofluorocarbons HCFC-21 and HCFC-123 was investigated. Methanotroph-linked oxidation of HCFC-21 was observed in aerobic soils, and anaerobic degradation of HCFC-21 occurred in freshwater and salt marsh sediments. Microbial degradation of HCFC-123 was observed in anoxic freshwater and salt marsh sediments, and the recovery of 1,1,1-trifluoro-2-chloroethane indicated the involvement of reductive dechlorination. No degradation of HCFC-123 was observed in aerobic soils. In some experiments, HCFCs were degraded at low (parts per billion) concentrations, raising the possibility that bacteria in nature remove HCFCs from the atmosphere. PMID:8633881

  6. Calcium Isotopes in Marine Sediments and Soils: Paleoceanography, Diagenesis, and Soil Processes

    NASA Astrophysics Data System (ADS)

    Depaolo, D. J.; Fantle, M. S.; Turchyn, A.; Ewing, S.; Yang, W.

    2007-12-01

    the sediment column. A deep-sea section where calcite is present in subequal proportions with clay, and in which there is also organic matter and rapid sulfate reduction, has a different pattern. Pore water 44Ca/40Ca values are closer to those of seawater, suggesting that there is virtually no calcite dissolution below a few meters depth. Analysis of the available data on fractionation during calcite precipitation suggests that the fractionation is controlled by attachment kinetics at the mineral surface. The observations also require that the presence of clay and/or organic material change the calcite dissolution rates by a large factor. Studies of Ca isotopes in hyper-arid soils and in alkaline lakes also show evidence of inorganic Ca isotope fractionation, probably controlled by relatively rapid, non-equilibrium precipitation of calcite, gypsum, or anhydrite during dessication events.

  7. Seasonal variation of polycyclic aromatic hydrocarbons in soil and air of Dalian areas, China: an assessment of soil-air exchange.

    PubMed

    Wang, Degao; Yang, Meng; Jia, Hongliang; Zhou, Lei; Li, Yifan

    2008-09-01

    The seasonal variations of concentrations of PAHs in the soil and the air were measured in urban and rural region of Dalian, China in 2007. In soil, mean concentrations of all PAHs in summer were larger than those in winter, whereas the concentrations of heavier weight PAHs in winter were larger than those in summer. Winter/summer concentration ratios for individual PAHs (R(W/S)) increased with the increase of molecular weight of PAHs in soil, indicating that PAHs with high molecular weight were more easily deposited to soil in winter than summer. In air, mean concentrations of all PAHs in winter were larger than those in summer. In comparison with the R(W/S) in soil, all the values of R(W/S) in air were larger than one indicating that the entire individual PAH concentrations in winter were larger than those in summer. The average concentration composition for each PAH compound in soil and air samples was determined and the seasonal change of PAH profile was very small. It was suggested that PAHs in soils and air had the same or similar sources both in winter and summer. The approach to the soil-air equilibrium was assessed by calculating fugacity quotients between soil and air using the soil and air concentrations. The calculated soil-air fugacity quotients indicated that soil acted as a secondary source to the atmosphere for all lighter weight PAHs (two-three rings) and it will continue to be a sink for heavier weight PAHs (five-six rings) in the Dalian environment, both in winter and summer. Medium weight PAHs (four-five rings) were close to the soil-air equilibrium and the tendency shifted between soil and air when season or function region changed. The fugacity quotients of PAHs in summer (mean temperature 298 K) were larger than those in winter (mean temperature 273 K), indicating a higher tendency in summer than winter for PAHs to move from soil to air. The variation of ambient conditions such as temperature, rainfall, etc. can influence the movement of PAHs

  8. Assessment of the AWC TRUclean process for use on Mound soils and sediments

    SciTech Connect

    Rogers, D.R.

    1989-03-23

    The AWC TRUclean System has been proposed as a method to reduce the volume of LSA waste during D&D excavation of Pu-238 contaminated soils on the Mound Site and Pu-238 contaminated sediments in the Miami-Erie Canal. Following test runs with Mound soil, AWC suggested that the TRUclean Process could reduce the amount of LSA waste by greater than 90% if a machine could be built and used to process the Mound soil. The cost savings which could potentially be realized by assuming this magnitude of volume reduction were thought to be significant on large projects. These preliminary results suggested that a review of the TRUclean Process and the 1987 test results should be performed to determine a course of action. The AWC TRUclean Process and the test data have been evaluated and the potential effectiveness of the process determined for use on Mound soils and/or on the sediments in the Miami-Erie Canal.

  9. Thermoelectric Air/Soil Energy-Harvesting Device

    NASA Technical Reports Server (NTRS)

    Snyder, Jeffrey; Fleurial, Jean-Pierre; Lawrence, Eric

    2005-01-01

    A proposed thermoelectric device would exploit natural temperature differences between air and soil to harvest small amounts of electric energy. Because the air/soil temperature difference fluctuates between nighttime and daytime, it is almost never zero, and so there is almost always some energy available for harvesting. Unlike photovoltaic cells, the proposed device could operate in the absence of sunlight. Unlike a Stirling engine, which could be designed to extract energy from the air/soil temperature difference, the proposed device would contain no moving parts. The main attractive feature of the proposed device would be high reliability. In a typical application, this device would be used for low-power charging of a battery that would, in turn, supply high power at brief, infrequent intervals for operating an instrumentation package containing sensors and communication circuits. The device (see figure) would include a heat exchanger buried in soil and connected to a heat pipe extending up to a short distance above the ground surface. A thermoelectric microgenerator (TEMG) would be mounted on top of the heat pipe. The TEMG could be of an advanced type, now under development, that could maintain high (relative to prior thermoelectric generators) power densities at small temperature differentials. A heat exchanger exposed to the air would be mounted on top of the TEMG. It would not matter whether the air was warmer than the soil or the soil warmer than the air: as long as there was a nonzero temperature difference, heat would flow through the device and electricity would be generated. A study of factors that could affect the design and operation of the device has been performed. These factors include the thermal conductances of the soil, the components of the device, the contacts between the components of the device, and the interfaces between the heat exchangers and their environments. The study included experiments that were performed on a model of the device

  10. Modeling 3D soil and sediment distributions for assessing catchment structure and hydrological feedbacks

    NASA Astrophysics Data System (ADS)

    Maurer, Thomas; Brück, Yasemine; Hinz, Christoph; Gerke, Horst H.

    2015-04-01

    Structural heterogeneity, namely the spatial distribution of soils and sediments (represented by mineral particles), characterizes catchment hydrological behavior. In natural catchments, local geology and the specific geomorphic processes determine the characteristics and spatial distribution of structures. In constructed catchments, structural features are determined primarily by the construction processes and the geological origin of the parent material. Objectives are scenarios of 3D catchment structures in form of complete 3D description of soil hydraulic properties generated from the knowledge of the formation processes. The constructed hydrological catchment 'Hühnerwasser' (Lower Lusatia, Brandenburg, Germany) was used for the calibration and validation of model results due to its well-known conditions. For the modelling of structural features, a structure generator was used to model i) quasi-deterministic sediment distributions using input data from a geological model of the parent material excavation site; ii) sediment distributions that are conditioned to measurement data from soil sampling; and iii) stochastic component sediment distributions. All three approaches allow a randomization within definable limits. Furthermore, the spoil cone / spoil ridge orientation, internal layering, surface compaction and internal spoil cone compaction were modified. These generated structural models were incorporated in a gridded 3D volume model constructed with the GOCAD software. For selected scenarios, the impact of structure variation was assessed by hydrological modelling with HYDRUS 2D/3D software. For that purpose, 3D distributions of soil hydraulic properties were estimated based on generated sediment properties using adapted pedotransfer functions. Results from the hydrological model were compared them to measured discharges from the catchment. The impact of structural feature variation on flow behaviour was analysed by comparing different simulation scenarios

  11. Ecoenzymatic Stoichiometry of Stream Sediments with Comparison to Terrestrial Soils

    EPA Science Inventory

    In this study, we extend the development of ecoenzymatic stoichiometry to the surface sediments of stream ecosystems using data collected in a nationwide survey. The data set is larger and more comprehensive than those used in our previous studies. The data include the first broa...

  12. Field controlled experiments of mercury accumulation in crops from air and soil.

    PubMed

    Niu, Zhenchuan; Zhang, Xiaoshan; Wang, Zhangwei; Ci, Zhijia

    2011-10-01

    Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation.

  13. Biogeochemistry of mercury in soils and sediments in a mining-impacted watershed, California

    NASA Astrophysics Data System (ADS)

    Holloway, J. M.; Goldhaber, M. B.

    2004-12-01

    The East Davis Creek watershed, located in the California Coast Ranges, is host to historic mines that provided mercury for recovery of gold in the Sierra Nevada goldfields in the mid-to-late 1800s. Bedrock in this watershed includes marine sedimentary rock, serpentinite, and hydrothermally altered serpentinite. Cinnabar (HgS) found in the altered serpentinite is the primary ore mineral for mercury. We evaluated the hypothesis that mercury is sequestered in soil organic matter downstream from source areas, releasing a fraction as water-soluble methylmercury. Microbial biomass and the presence of sulfur-reducing bacteria implicated in mercury methylation were quantified using phospholipid fatty acid (PLFA) data. Methylation incubations were performed on soil and sediment inoculated with water from Davis Creek Reservoir and sealed in glass containers under an anoxic headspace for 21 days. Methylmercury was measured on extracts of the soils at the start and at the end of the incubation period. Two sources of mercury to stream sediments, a soil with an altered serpentinite parent and mine tailings, were incubated. Stream sediment, an overbank deposit soil and a wetland soil forming from these sediments were also incubated. The overbank deposit soil is periodically flooded. The wetland soil around the edge of Davis Creek Reservoir is perennially saturated with water. The altered serpentinite soil and mine tailings had the highest total mercury concentrations (170 and 150 ng Hg /g, respectively). Total mercury concentrations in stream sediments are low (¡Ü1 ng Hg/g), with higher mercury concentrations in the overbank (3 ng/g) and wetland soils (18 ng Hg/g). Mercury leached from altered serpentinite soils and mine tailings may be transported downstream and sequestered through sorption to organic matter in the overbank and wetland soils. PLFA biomarkers for Desulfobacter (10Me16:0) and Desulfovibrio (i17:1) were present in all incubated materials, with lower

  14. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

    PubMed Central

    Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  15. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  16. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-11-10

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality.

  17. Zircon geochronology of loess and alluvial sediment: implications for provenance of modern soils of Middle Tennessee

    NASA Astrophysics Data System (ADS)

    Wang, X.; Ayers, J. C.; Katsiaficas, N. J.

    2014-12-01

    Soils in Middle Tennessee are commonly observed on limestone bedrock. However, comparison of zircon U-Pb age spectra of soil and bedrock (Ayers and Katsiaficas, unpublished data) suggests that there is a small but significant exotic (externally derived) zircon component. Potential sources of exotic zircon include loess and alluvial sediments. In western Tennessee the Roxana Silt was deposited 38-53 ka and the Peoria Loess 18-25 ka. Detrital zircon U-Pb geochronology is a direct and effective way to test the possibility of loess as a contributor to the source material of the soil. According to Aleinikoff et al. (2008), loess from Colorado and Nebraska have young detrital zircon age peaks at ~34Ma. If this is also true for the loess in Tennessee, it may explain the ~33 Ma age peak found in one of the three studied soil samples. To identify the source of the exotic zircon found in middle TN soils, zircon age spectra will be measured for Roxana Silt, Peoria Loess, and alluvial sediments from the Harpeth and Cumberland Rivers. The loess samples were collected near Memphis, TN, while the alluvial sediments were collected near the soil sample sites.

  18. Geochemical features of rocks, stream sediments, and soils of the Fiume Grande Valley (Calabria, Italy)

    NASA Astrophysics Data System (ADS)

    Apollaro, Carmine; Marini, Luigi; de Rosa, Rosanna; Settembrino, Paolo; Scarciglia, Fabio; Vecchio, Giuseppe

    2007-04-01

    The role of both natural weathering and anthropogenic pollution in controlling the distribution of major oxides and several trace elements in soils, stream sediments, and rocks of the Fiume Grande catchment was evaluated. The contents of major oxides and trace elements in soils appear to be governed by weathering and pedogenetic processes, although the use of fertilizers in agriculture could also partly affect K2O and P2O5 contents. Stream sediments have concentrations of major oxides (except CaO) very similar to soils, as relevant amounts of soil materials are supplied to the stream channels by erosive phenomena. In contrast, stream sediments have concentrations of Cr, Co, Ni, Zn, As, and Pb significantly higher than those of soils, probably due to different conditions and rates of mobility of these elements within the three considered matrices and/or disposal of wastes in the drainage network. Comparison of the concentrations of PHEs in soils with the maximum admissible contents established by the Italian law shows that these limits are too restrictive in some cases and too permissive in other ones. The approach of setting these limits with no consideration for the local geological geochemical framework may lead to improper management of the territory and its resources.

  19. Soil/sediment characterization for 216-A-29 ditch

    SciTech Connect

    Mitchell, R.M.

    1997-03-01

    This document provides a detailed description of the environmental samples collected from the 216-A-29 Ditch in 1988. Tables summarizing the laboratory data for radionuclides, metals, and soil chemistry are included.

  20. Soil air and soil flux measurements of 222Radon and CO2: A soil flux parametrization at Lutjewad (NL)

    NASA Astrophysics Data System (ADS)

    Neubert, R. E. M.; Kettner, E.; Palstra, S. W. L.; Hoekman, S.; van der Graaf, E. R.

    2009-04-01

    Atmospheric 222Radon concentration measurements are used as a valuable transport tracer verifying the transport part of Carbon Cycle and Greenhouse Gas models. The production rate of the radioactive noble gas 222Radon (T1•2 = 3.8 days) by radioactive decay of 226Radium in the soil is constant, the absolute quantity depending on the local soil Radium concentration. The flux of 222Radon to the atmosphere (the soil exhalation, or effective atmospheric production rate), however, is not constant. It strongly depends on soil texture, soil humidity, precipitation and other parameters, but is nearly constant if these parameters stay unchanged. Recently, an effort has been done to predict this flux rate with widely available γ-dosimetry measurements (Szegvary et al., Predicting terrestrial 222Rn-flux using gamma dose rate as a proxy, ACP 7, 2789-2795, 2007), but real 222Radon-flux measurements are sparse. 222Radon undergoes the same transport processes on the way from soil to atmosphere as any other soil-derived (greenhouse) gas. This makes 222Radon an ideal tracer to separate variations in e.g. soil CO2-production from changes in the soil-atmosphere CO2-transport, both being reflected in the total soil-atmosphere CO2-flux. At the atmospheric measurement site Lutjewad in the north of the Netherlands (53N24'18", 6E21'13", www.rug.nl/ees/onderzoek/cio/projecten/atmosphericgases) we started in 2006 with the measurements of the soil 222Radon and CO2 concentration through soil probes as well as the Radon and CO2 soil fluxes by means of an automatic soil chamber. While there are up to eight soil air measurements per day, the soil chamber is automatically closed twice per day. The station is situated directly on the Waddensea dike at an elevation of 1 m a.s.l. on seaclay soil. The groundwater table shows variations between 0.5 m and 2 m below terrain. From our measurements we find that in the dryer summer season, from April to July, the mean 222Radon-flux can be up to 40

  1. Comparison of quantification methods to measure fire-derived (black/elemental) carbon in soils and sediments using reference materials from soil, water, sediment and the atmosphere

    NASA Astrophysics Data System (ADS)

    Hammes, Karen; Schmidt, Michael W. I.; Smernik, Ronald J.; Currie, Lloyd A.; Ball, William P.; Nguyen, Thanh H.; Louchouarn, Patrick; Houel, Stephane; Gustafsson, Örjan; Elmquist, Marie; Cornelissen, Gerard; Skjemstad, Jan O.; Masiello, Caroline A.; Song, Jianzhong; Peng, Ping'an; Mitra, Siddhartha; Dunn, Joshua C.; Hatcher, Patrick G.; Hockaday, William C.; Smith, Dwight M.; Hartkopf-Fröder, Christoph; BöHmer, Axel; Lüer, Burkhard; Huebert, Barry J.; Amelung, Wulf; Brodowski, Sonja; Huang, Lin; Zhang, Wendy; Gschwend, Philip M.; Flores-Cervantes, D. Xanat; Largeau, Claude; Rouzaud, Jean-NoëL.; Rumpel, Cornelia; Guggenberger, Georg; Kaiser, Klaus; Rodionov, Andrei; Gonzalez-Vila, Francisco J.; Gonzalez-Perez, José A.; de La Rosa, José M.; Manning, David A. C.; López-CapéL, Elisa; Ding, Luyi

    2007-09-01

    Black carbon (BC), the product of incomplete combustion of fossil fuels and biomass (called elemental carbon (EC) in atmospheric sciences), was quantified in 12 different materials by 17 laboratories from different disciplines, using seven different methods. The materials were divided into three classes: (1) potentially interfering materials, (2) laboratory-produced BC-rich materials, and (3) BC-containing environmental matrices (from soil, water, sediment, and atmosphere). This is the first comprehensive intercomparison of this type (multimethod, multilab, and multisample), focusing mainly on methods used for soil and sediment BC studies. Results for the potentially interfering materials (which by definition contained no fire-derived organic carbon) highlighted situations where individual methods may overestimate BC concentrations. Results for the BC-rich materials (one soot and two chars) showed that some of the methods identified most of the carbon in all three materials as BC, whereas other methods identified only soot carbon as BC. The different methods also gave widely different BC contents for the environmental matrices. However, these variations could be understood in the light of the findings for the other two groups of materials, i.e., that some methods incorrectly identify non-BC carbon as BC, and that the detection efficiency of each technique varies across the BC continuum. We found that atmospheric BC quantification methods are not ideal for soil and sediment studies as in their methodology these incorporate the definition of BC as light-absorbing material irrespective of its origin, leading to biases when applied to terrestrial and sedimentary materials. This study shows that any attempt to merge data generated via different methods must consider the different, operationally defined analytical windows of the BC continuum detected by each technique, as well as the limitations and potential biases of each technique. A major goal of this ring trial was

  2. Using geochemical indicators to distinguish high biogeochemical activity in floodplain soils and sediments.

    PubMed

    Kenwell, Amy; Navarre-Sitchler, Alexis; Prugue, Rodrigo; Spear, John R; Hering, Amanda S; Maxwell, Reed M; Carroll, Rosemary W H; Williams, Kenneth H

    2016-09-01

    A better understanding of how microbial communities interact with their surroundings in physically and chemically heterogeneous subsurface environments will lead to improved quantification of biogeochemical reactions and associated nutrient cycling. This study develops a methodology to predict potential elevated rates of biogeochemical activity (microbial "hotspots") in subsurface environments by correlating microbial DNA and aspects of the community structure with the spatial distribution of geochemical indicators in subsurface sediments. Multiple linear regression models of simulated precipitation leachate, HCl and hydroxylamine extractable iron and manganese, total organic carbon (TOC), and microbial community structure were used to identify sample characteristics indicative of biogeochemical hotspots within fluvially-derived aquifer sediments and overlying soils. The method has been applied to (a) alluvial materials collected at a former uranium mill site near Rifle, Colorado and (b) relatively undisturbed floodplain deposits (soils and sediments) collected along the East River near Crested Butte, Colorado. At Rifle, 16 alluvial samples were taken from 8 sediment cores, and at the East River, 46 soil/sediment samples were collected across and perpendicular to 3 active meanders and an oxbow meander. Regression models using TOC and TOC combined with extractable iron and manganese results were determined to be the best fitting statistical models of microbial DNA (via 16S rRNA gene analysis). Fitting these models to observations in both contaminated and natural floodplain deposits, and their associated alluvial aquifers, demonstrates the broad applicability of the geochemical indicator based approach. PMID:27145490

  3. Watershed Sediment Losses to Lakes Accelerating Despite Agricultural Soil Conservation Efforts

    PubMed Central

    Heathcote, Adam J.; Filstrup, Christopher T.; Downing, John A.

    2013-01-01

    Agricultural soil loss and deposition in aquatic ecosystems is a problem that impairs water quality worldwide and is costly to agriculture and food supplies. In the US, for example, billions of dollars have subsidized soil and water conservation practices in agricultural landscapes over the past decades. We used paleolimnological methods to reconstruct trends in sedimentation related to human-induced landscape change in 32 lakes in the intensively agricultural region of the Midwestern United States. Despite erosion control efforts, we found accelerating increases in sediment deposition from erosion; median erosion loss since 1800 has been 15.4 tons ha−1. Sediment deposition from erosion increased >6-fold, from 149 g m−2 yr−1 in 1850 to 986 g m−2 yr−1 by 2010. Average time to accumulate one mm of sediment decreased from 631 days before European settlement (ca. 1850) to 59 days mm−1 at present. Most of this sediment was deposited in the last 50 years and is related to agricultural intensification rather than land clearance or predominance of agricultural lands. In the face of these intensive agricultural practices, traditional soil conservation programs have not decelerated downstream losses. Despite large erosion control subsidies, erosion and declining water quality continue, thus new approaches are needed to mitigate erosion and water degradation. PMID:23326454

  4. Watershed sediment losses to lakes accelerating despite agricultural soil conservation efforts.

    PubMed

    Heathcote, Adam J; Filstrup, Christopher T; Downing, John A

    2013-01-01

    Agricultural soil loss and deposition in aquatic ecosystems is a problem that impairs water quality worldwide and is costly to agriculture and food supplies. In the US, for example, billions of dollars have subsidized soil and water conservation practices in agricultural landscapes over the past decades. We used paleolimnological methods to reconstruct trends in sedimentation related to human-induced landscape change in 32 lakes in the intensively agricultural region of the Midwestern United States. Despite erosion control efforts, we found accelerating increases in sediment deposition from erosion; median erosion loss since 1800 has been 15.4 tons ha(-1). Sediment deposition from erosion increased >6-fold, from 149 g m(-2) yr(-1) in 1850 to 986 g m(-2) yr(-1) by 2010. Average time to accumulate one mm of sediment decreased from 631 days before European settlement (ca. 1850) to 59 days mm(-1) at present. Most of this sediment was deposited in the last 50 years and is related to agricultural intensification rather than land clearance or predominance of agricultural lands. In the face of these intensive agricultural practices, traditional soil conservation programs have not decelerated downstream losses. Despite large erosion control subsidies, erosion and declining water quality continue, thus new approaches are needed to mitigate erosion and water degradation.

  5. Dechlorinating chloroacetanilide herbicides by dithionite-treated aquifer sediment and surface soil.

    PubMed

    Boparai, Hardiljeet K; Shea, Patrick J; Comfort, Steve D; Snow, Daniel D

    2006-05-01

    The prevalent use of chloroacetanilide herbicides has resulted in nonpoint contamination of some groundwater and surface water. We determined the efficacy of dithionite-treated sediment and soils to transform chloroacetanilides. When used alone, dithionite rapidly dechlorinates chloroacetanilides in water, with the following order of reactivity: propachlor > alachlor > acetochlor > metolachlor. Stoichiometric release of chloride occurs during reaction with dithionite, and thiosulfate herbicide derivatives are produced. Treating aquifer sediment with dithionite reduces native Fe(lII), creating a redox barrier of Fe(ll)-bearing minerals and surface-bound Fe(ll). Washing the reduced sediment (buffered with citrate-bicarbonate) with oxygen-free water removed Fe(ll) and excess dithionite and no alachlor transformation was observed. In contrast, a dithionite-treated surface soil, rich in clay and iron, effectively dechlorinated alachlor after washing. Exposing alachlor to aquifer sediment treated with dithionite in potassium carbonate buffer (pH 8.5-9.0) produced dechlorinated alachlor as the major degradation product. Our results provide proof-of-concept that dechlorination of chloroacetanilide herbicides by dithionite and dithionite-treated aquifer sediment and soil is a remediation option in natural environments where iron-bearing minerals are abundant.

  6. Arsenic contamination in water, soil, sediment and rice of central India.

    PubMed

    Patel, K S; Shrivas, K; Brandt, R; Jakubowski, N; Corns, W; Hoffmann, P

    2005-04-01

    Arsenic contamination in the environment (i.e. surface, well and tube-well water, soil, sediment and rice samples) of central India (i.e. Ambagarh Chauki, Chhattisgarh) is reported. The concentration of the total arsenic in the samples i.e. water (n = 64), soil (n = 30), sediment (n = 27) and rice grain (n = 10) were ranged from 15 to 825 microg L(-1), 9 to 390 mg kg(-1), 19 to 489 mg kg(-1) and 0.018 to 0.446 mg kg(-1), respectively. In all type of waters, the arsenic levels exceeded the permissible limit, 10 microg L(-1). The most toxic and mobile inorganic species i.e. As(III) and As(V) are predominantly present in water of this region. The soils have relatively higher contents of arsenic and other elements i.e. Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Ga, Zr, Sn, Sb, Pb and U. The mean arsenic contents in soil of this region are much higher than in arsenic soil of West Bengal and Bangladesh. The lowest level of arsenic in the soil of this region is 3.7 mg kg(-1) with median value of 9.5 mg kg(-1). The arsenic contents in the sediments are at least 2-folds higher than in the soil. The sources of arsenic contamination in the soil of this region are expected from the rock weathering as well as the atmospheric deposition. The environmental samples i.e. water, soil dust, food, etc. are expected the major exposure for the arsenic contamination. The most of people living in this region are suffering with arsenic borne diseases (i.e. melanosis, keratosis, skin cancer, etc.).

  7. Arsenic contamination in water, soil, sediment and rice of central India.

    PubMed

    Patel, K S; Shrivas, K; Brandt, R; Jakubowski, N; Corns, W; Hoffmann, P

    2005-04-01

    Arsenic contamination in the environment (i.e. surface, well and tube-well water, soil, sediment and rice samples) of central India (i.e. Ambagarh Chauki, Chhattisgarh) is reported. The concentration of the total arsenic in the samples i.e. water (n = 64), soil (n = 30), sediment (n = 27) and rice grain (n = 10) were ranged from 15 to 825 microg L(-1), 9 to 390 mg kg(-1), 19 to 489 mg kg(-1) and 0.018 to 0.446 mg kg(-1), respectively. In all type of waters, the arsenic levels exceeded the permissible limit, 10 microg L(-1). The most toxic and mobile inorganic species i.e. As(III) and As(V) are predominantly present in water of this region. The soils have relatively higher contents of arsenic and other elements i.e. Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Ga, Zr, Sn, Sb, Pb and U. The mean arsenic contents in soil of this region are much higher than in arsenic soil of West Bengal and Bangladesh. The lowest level of arsenic in the soil of this region is 3.7 mg kg(-1) with median value of 9.5 mg kg(-1). The arsenic contents in the sediments are at least 2-folds higher than in the soil. The sources of arsenic contamination in the soil of this region are expected from the rock weathering as well as the atmospheric deposition. The environmental samples i.e. water, soil dust, food, etc. are expected the major exposure for the arsenic contamination. The most of people living in this region are suffering with arsenic borne diseases (i.e. melanosis, keratosis, skin cancer, etc.). PMID:16003581

  8. IMMUNOASSAY METHOD FOR THE DETERMINATION OF PENTACHLOROPHENOL IN SOIL AND SEDIMENT

    EPA Science Inventory

    The journal article describes the use of a prototype immunoassay method for the determination of pentacholorphenol (PCP) in soil and sediment. PCP was used as a pesticide and wood preservative and is not currently available to the general public. The paper stresses the importan...

  9. Determination of Polychlorinated Biphenyls in Soil and Sediment by Selective Pressurized Liquid Extraction with Immunochemical Detection

    EPA Science Inventory

    A selective liquid pressurized extraction (SPLE) method was developed as a streamlined sample preparation/cleanup procedure for determining Aroclors and coplanar polychlorinated biphenyls (PCBs) in soil and sediment matrices. The SPLE method was coupled with an enzyme-linked imm...

  10. DEMONSTRATION AND QUALITY ASSURANCE PROJECT PLAN: XRF TECHNOLOGIES OF MEASURING TRACE ELEMENTS IN SOIL AND SEDIMENT

    EPA Science Inventory

    A demonstration of field portable/mobile technologies for measuring trace elements in soil and sediments was conducted under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation (SITE) Program. The demonstration took place from January 24 to 28, 200...

  11. UTILIZATION OF BACTERIA TO REMEDIATE CONTAMINATED SOILS AND SEDIMENTS IN THE US: LASAGNA AND OTHER TREATMENTS

    EPA Science Inventory

    This is an overview of the work underway at USEPA/ORD/NRMRL's Center Hill Microbiology Laboratory on bioremediation of contaminated soils and sediments. The Laboratory has isolated and naturally selected for various isolates. An isolate that will be reviewed is CHL-004, a Pseudom...

  12. AN OVERVIEW OF PARTITIONING AND BIOAVAILABILITY OF PAHS IN SEDIMENTS AND SOILS

    EPA Science Inventory

    Understanding and predicting any adverse effects of PAHs depends on generating a reliable measure or estimate of how much PAH is available for uptake. Simply knowing the total amount of PAH in soil, water or sediment is insufficient for determining whether or not these compounds ...

  13. MANAGING ARSENIC CONTAMINATED SOIL, SEDIMENT, AND INDUSTRIAL WASTE WITH SOLIDIFICATION/STABILIZATION TREATMENT

    EPA Science Inventory

    Arsenic contamination of soil, sediment and groundwater is a widespread problem in certain areas and has caused great public concern due to increased awareness of the health risks. Often the contamination is naturally occurring, but it can also be a result of waste generated from...

  14. AUTOMATED GIS WATERSHED ANALYSIS TOOLS FOR RUSLE/SEDMOD SOIL EROSION AND SEDIMENTATION MODELING

    EPA Science Inventory

    A comprehensive procedure for computing soil erosion and sediment delivery metrics has been developed using a suite of automated Arc Macro Language (AML ) scripts and a pair of processing- intensive ANSI C++ executable programs operating on an ESRI ArcGIS 8.x Workstation platform...

  15. ENGINEERING ISSUE: TECHNOLOGY ALTERNATIVES FOR THE REMEDIATION OF PCB-CONTAMINATED SOIL AND SEDIMENT

    EPA Science Inventory

    Because of the increased need for Superfund decision-makers to have a working knowledge of the remedial capabilities available to treat soil and sediment contaminated with polychlorinated biphenyls (PCBs), the Superfund Engineering Forum has identified remediation of PCB-contamin...

  16. Phosphorus Dynamics in Soil, Runoff, and Sediment from Three Management Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land application of poultry litter can lead to increased phosphorus (P) level in surface runoff and sediment, which in turn, potentially accelerates the eutrophication in the water bodies. The objective of this research was to study the P dynamics in two poultry litter amended soils using three mana...

  17. IN-SITU REMEDIATION OF CHROMIUM-CONTAMINATED SOILS AND SEDIMENTS

    EPA Science Inventory

    The objectives of this study were to characterize the extent of total chromium and Cr(VI)contamination in the underlying soils and sediments of a chrome-plating shop at the USCG Support Center near Elizabeth City, NC and to evaluate the use of liquid reductants for in situ treatm...

  18. IN-SITU REDUCTION OF CHROMIUM-CONTAMINATED GROUNDWATER, SOILS, AND SEDIMENTS BY SODIUM DITHIONITE

    EPA Science Inventory

    Laboratory studies were conducted to characterize the extent of chromium contamination in the groundwater and underlying soils and sediments of a chrome-plating shop at the USCG Support Center near Elizabeth City, NC. Most of the mobile Cr(VI) is present in the capillary zone ...

  19. Sediment source identification in a semiarid watershed at soil mapping unit scales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selective erosion and transport of silt and clay-particles from watershed soil surfaces leads to enrichment of suspended sediments by size fractions that are the most effective scavengers of chemical pollutants. Thus, preferential transport of highly reactive size fractions represents a major proble...

  20. Mercury Release from Soils and Sediments in the Sacramento River Watershed

    NASA Astrophysics Data System (ADS)

    Suess, E.; Aiken, G. R.; Ryan, J. N.; Gasper, J. D.

    2007-12-01

    Mercury released into water from soils and sediments contaminated by cinnabar (HgS) and gold mining is a major environmental concern in the Sacramento-San Joaquin Delta, California. To better understand the conditions resulting in Hg solubilization from these contaminated materials, six soil and sediment samples from the Coastal Range and the Sierra Nevada were subject to batch leaching experiments under varying conditions. Sequential extraction analyses of the soils and sediments indicated that most of the mercury was present as (1) Hg as HgS in samples affected by HgS mining, which occurred in the Coastal Range, (2) Hg bound to metal oxides in a background serpentine soil from the Coastal Range, (3) Hg bound to sediment organic matter in lake sediments from Camp Far West Reservoir, and (4) elemental Hg in a sluice sediment from Starr Tunnel. The effects of pH, ionic strength, inorganic ions (chloride, calcium), simple organic ligands (mercaptoacetic acid, salicylic acid, EDTA), and dissolved organic matter (DOM) on the release of Hg were investigated. Leaching experiments confirmed that the water-soluble fraction was small (9 to 350 ng/L) compared to the amounts of Hg associated with the solid samples (1 to 36 μg/g total mercury); however, these concentrations would be sufficient to result in increased methylation by sulfate-reducing bacteria in wetland systems. An increase in mercury release was observed with (1) increasing pH due to solubilization of soil organic matter, (2) decreasing ionic strength due to colloid stabilization, and (3) increasing chloride concentration due to the formation of complexes with mercury. The presence of calcium strongly inhibited mercury release. Among the organic ligands, mercaptoacetic acid, which binds Hg very strongly, was the most effective at solubilizing Hg. DOM, in the form of organic matter isolates, was also very effective at solubilizing Hg for all samples except the lake sediment sample, with the most aromatic organic

  1. Mercury speciation in floodplain soils and sediments along a contaminated river transect

    SciTech Connect

    Wallschlaeger, D.; Desai, M.V.M.; Spengler, M.; Wilken, R.D.

    1998-09-01

    A novel mercury-specific sequential extraction procedure (SEP) for the assessment of mercury (Hg) speciation in soils and sediments, with emphasis on studying the interaction between Hg and organic matter (OM), was developed and tested. It was applied to determine Hg speciation in floodplain topsoils and surface sediments along the Hg-contaminated part of the river Elbe, and to simultaneously derive some information on the (re)mobilization potentials for Hg from these matrices. The majority of the total Hg in the ecosystem today is bound in the floodplains, which also still geographically reflect the historic emission record. Most of the Hg in both matrices is bound strongly to OM, suggesting low availability. However, distinct differences between Hg speciation in the floodplain soils and sediments were also discovered. Mercury deposited in the floodplains shows speciation patterns that indicate stronger fixation compared with Hg in the sediments. This difference is attributed to the association of Hg with larger quantities of OM, which presumably also has higher molecular weight (MW). By comparison, Hg in the sediments was distributed among weaker binding forms, which are more likely to liberate Hg. Particularly, sediments showed a total lack of sulfidic binding forms for Hg. Pronounced geographical trends were detected in the Hg speciation along the river transect, with a general downstream shift from weaker to stronger binding forms, probably due to increased association with OM. These studies indicate that Hg speciation in riverine ecosystems is dynamic and reflects the chemical mechanisms underlying (bio) geochemical processes like distribution and transport.

  2. Linking the field to the stream: soil erosion and sediment yield in a rural catchment, NW Spain

    NASA Astrophysics Data System (ADS)

    Rodriguez-Blanco, M. L.; Taboada-Castro, M. M.; Palleiro-Suarez, L.; Taboada-Castro, M. T.

    2009-04-01

    Quantifying the linkages between field erosion, fluvial response and catchment sediment yield remains problematic, among other reasons, because of the re-deposition of eroded sediment within the catchment, which is controlled by the spatial organization of the land use and the connectivity between sediment sources and the stream network. This paper presents the results of an integrated study that considered the relationship between erosion and stream sediment yield in an agroforestry catchment (16 km2) in NW Spain. The geology consists of basic metamorphic schist. The relieve of the area is steeper, the mean slope is approximately 19%. Main soil types are classified as Umbrisol and Cambisol. Soils are acidic and rich in organic matter. The soil texture is silt and silt-loam. Land cover consists of a mixture of forest (65%) and agricultural fields (mainly grassland, pasture and maize). The study combined measurements of soil erosion by concentrate flow and sediment deposition at field scale with sediment yield measured at the catchment outlet. The hydrological data and water samples were obtained at the catchment outlet. Stream water level was monitored continuously and converted to discharge using a rating curve. The sampling for suspended sediments was supplemented by an automatic sampler. Suspended sediment load was calculated from the suspended sediment concentrations and discharge data. Eroded volume was calculated from cross-sections (measured at specific points, where the section changed abruptly) and length of the channel segments. The total sediment delivered to stream was determined as the difference between all erosion features (rills and gullies) and the sediment volumes that were deposited on the fields. The results showed that in the catchment during the period winter 2007/08 soil erosion by concentrate flow, i.e. rills and ephemeral gullies, occurred on unprotected crop field. Erosion by concentrate flow was highly discontinuous within the catchment

  3. Soil disturbance/restoration effects on stream sediment loading in the Tahoe Basin--detection monitoring.

    PubMed

    Grismer, M E

    2014-07-01

    Quantifying the relative impacts of soil restoration or disturbance on watershed daily sediment and nutrients loads is essential towards assessing the actual costs/benefits of the land management. Such quantification requires stream monitoring programs capable of detecting changes in land-use or soil functional and erosive area "connectivity" conditions across the watershed. Previously, use of a local-scale, field-data based runoff and erosion model for three Lake Tahoe west-shore watersheds as a detection monitoring "proof of concept" suggested that analyses of midrange average daily flows can reveal sediment load reductions of relatively small watershed fractional areas (∼5 %) of restored soil function within a few years of treatment. Developing such an effective stream monitoring program is considered for tributaries on the west shore of the Lake Tahoe Basin using continuous (15-min) stream monitoring information from Ward (2,521 ha), Blackwood (2,886 ha), and the Homewood (260 ha, HMR) Creek watersheds. The continuous total suspended sediment (TSS) and discharge monitoring confirmed the hysteretic TSS concentration-flowrate relationship associated with the daily and seasonal spring snowmelt hydrographs at all three creeks. Using the complete dataset, daily loads estimated from 1-h sampling periods during the day indicated that the optimal sampling hours were in the afternoon during the rising limb of the spring snowmelt hydrograph, an observation likely to apply across the Sierra Nevada and other snowmelt driven watersheds. Measured rising limb sediment loads were used to determine if soils restoration efforts (e.g., dirt road removal, ski run rehabilitation) at the HMR creek watershed reduced sediment loads between 2010 and 2011. A nearly 1.5-fold decrease in sediment yields (kg/ha per m(3)/s flow) was found suggesting that this focused monitoring approach may be useful towards development of TMDL "crediting" tools. Further monitoring is needed to verify

  4. Soil disturbance/restoration effects on stream sediment loading in the Tahoe Basin--detection monitoring.

    PubMed

    Grismer, M E

    2014-07-01

    Quantifying the relative impacts of soil restoration or disturbance on watershed daily sediment and nutrients loads is essential towards assessing the actual costs/benefits of the land management. Such quantification requires stream monitoring programs capable of detecting changes in land-use or soil functional and erosive area "connectivity" conditions across the watershed. Previously, use of a local-scale, field-data based runoff and erosion model for three Lake Tahoe west-shore watersheds as a detection monitoring "proof of concept" suggested that analyses of midrange average daily flows can reveal sediment load reductions of relatively small watershed fractional areas (∼5 %) of restored soil function within a few years of treatment. Developing such an effective stream monitoring program is considered for tributaries on the west shore of the Lake Tahoe Basin using continuous (15-min) stream monitoring information from Ward (2,521 ha), Blackwood (2,886 ha), and the Homewood (260 ha, HMR) Creek watersheds. The continuous total suspended sediment (TSS) and discharge monitoring confirmed the hysteretic TSS concentration-flowrate relationship associated with the daily and seasonal spring snowmelt hydrographs at all three creeks. Using the complete dataset, daily loads estimated from 1-h sampling periods during the day indicated that the optimal sampling hours were in the afternoon during the rising limb of the spring snowmelt hydrograph, an observation likely to apply across the Sierra Nevada and other snowmelt driven watersheds. Measured rising limb sediment loads were used to determine if soils restoration efforts (e.g., dirt road removal, ski run rehabilitation) at the HMR creek watershed reduced sediment loads between 2010 and 2011. A nearly 1.5-fold decrease in sediment yields (kg/ha per m(3)/s flow) was found suggesting that this focused monitoring approach may be useful towards development of TMDL "crediting" tools. Further monitoring is needed to verify

  5. Suspended sediment from the Gangotri Glacier: Quantification, variability and associations with discharge and air temperature

    NASA Astrophysics Data System (ADS)

    Haritashya, Umesh K.; Singh, Pratap; Kumar, Naresh; Gupta, R. P.

    2006-04-01

    To understand the sediment delivery variation for a Himalayan Glacier (Gangotri Glacier, Garhwal Himalayas) and to determine its relationship with discharge and air temperature, suspended sediment samples and discharge data were collected near the glacier snout (4000 m) for four melt seasons during the period 2000-2003. These data were used to estimate suspended sediment concentration (SSC), suspended sediment load (SSL), sediment yield and erosion rate in the glacier melt stream (Bhagirathi). The monthly distribution of suspended sediment and its variability from year to year have been examined. Mean monthly SSC for May, June, July, August, September and October were found to be 1942, 2063, 3658, 2551, 734 and 136 mg l -1, respectively. Maximum SSC in meltwater was observed in July followed by August. It was found that the cumulative percentage delivery of SSC precedes discharge throughout the melt season. Mean monthly total SSL for May, June, July, August, September and October during the study period was found to be 149, 423, 1220, 746, 143 and 5×10 3 ton, respectively. The strong variability is found in SSL ( Cv=1.1) than SSC ( Cv=0.8) because computation of SSL includes both discharge ( Cv=0.6) and SSC. Delivery response of SSL in terms of percentage of total load is less in the early part of the melt season than in the later stage in comparison to that of discharge. This may be due to the fact that in the beginning of the melt season low melt rate conditions prevails and thus, the low discharge velocity could not flush out stored glacial sediment. It has been observed that 59-64% of the sediment passed through the channel by the time 50% of the total discharge passed. The average suspended sediment yield for the whole melt season from the study area was estimated to be about 4834 ton km -2 and corresponding erosion rate was 1.8 mm. The relationship between mean monthly SSC and discharge ( R2=0.99) is much better than the daily SSC and discharge ( R2

  6. Distribution of Glycerol Diakyl Glycerol Tetraethers in Surface Soil and Crater Lake Sediments from Mount Kenya, East Africa

    NASA Astrophysics Data System (ADS)

    Omuombo, C.; Huguet, A.; Olago, D.; Williamson, D.

    2013-12-01

    Glycerol diakyl glycerol tetraethers (GDGTs), a palaeoclimate proxy based on the relative abundance of lipids produced by archaea and bacteria, is gaining wide acceptance for the determination of past temperature and pH conditions. This study looks at the spatial distribution and abundance of GDGTs in soil and sediment samples along an altitudinal transect from 3 crater lakes of Mt. Kenya (Lake Nkunga, Sacred Lake and Lake Rutundu) ranging in elevation from 1700m - 3080m above sea level. GDGTs were extracted with solvents and then analysed using high performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS). Mean annual air temperature and pH were estimated based on the relative abundance of the different branched GDGTs, i.e. on the MBT (Methylation index of Branched Tetraethers) and CBT (Cyclization ratio of Branched Tetraethers) indices. Substantial amount of GDGTs were detected in both soil and sediment samples. In addition, branched GDGT distribution was observed to vary with altitude. These results highlight the importance of quantifying the branched GDGTs to understand the environmental parameters controlling the distribution of these lipids. The MBT/CBT proxy is a promising tool to infer palaeotemperatures and characterize the climate events of the past millennia in equatorial east Africa.

  7. Meteoric cosmogenic Beryllium-10 adsorbed to river sediment and soil: Applications for Earth-surface dynamics

    NASA Astrophysics Data System (ADS)

    Willenbring, Jane K.; von Blanckenburg, Friedhelm

    2010-01-01

    Rainfall scavenges meteoric cosmogenic 10Be from the atmosphere. 10Be falls to the Earth's surface, where it binds tightly to sediment particles in non-acidic soils over the life-span of those soils. As such, meteoric 10Be has the potential to be an excellent geochemical tracer of erosion and stability of surfaces in a diverse range of natural settings. Meteoric 10Be has great potential as a recorder of first-order erosion rates and soil residence times. Even though this tracer was first developed in the late 1980s and showed great promise as a geomorphic tool, it was sidelined in the past two decades with the rise of the "sister nuclide", in situ10Be, which is produced at a known rate inside quartz minerals. Since these early days, substantial progress has been made in several areas that now shed new light on the applicability of the meteoric variety of this cosmogenic nuclide. Here, we revisit the potential of this tracer and we summarize the progress: (1) the atmospheric production and fallout is now described by numeric models, and agrees with present-day measurements and paleo-archives such as from rain and ice cores; (2) short-term fluctuations in solar modulation of cosmic rays or in the delivery of 10Be are averaged out over the time scale soils accumulate; (3) in many cases, the delivery of 10Be is not dependent on the amount of precipitation; (4) we explore where 10Be is retained in soils and sediment; (5) we suggest a law to account for the strong grain-size dependence that controls adsorption and the measured nuclide concentrations; and (6) we present a set of algebraic expressions that allows calculation of both soil or sediment ages and erosion rates from the inventory of meteoric 10Be distributed through a vertical soil column. The mathematical description is greatly simplified if the accumulation of 10Be is at a steady state with its export through erosion. In this case, a surface sample allows for the calculation of an erosion rate. Explored

  8. Significance of experimental design in evaluating ecological hazards of sediments/soils to amphibian species

    SciTech Connect

    Fort, D.J.; Stover, E.L.

    1997-09-01

    In an effort to determine the significance of experimental design on the results of laboratory sediment toxicity studies with amphibians (Xenopus laevis), two different sample preparations were evaluated from three different contaminated waste sites. Whole sediment and aqueous sediment extracts from each site were evaluated. Site 1 soil was characterized as loamy with a relatively high total organic carbon (TOC), moisture fraction (MF), and sulfide content; and contaminated with organochlorine pesticides. Site 2 soil was characterized as silty-clay with low/moderate TOC, MF, and sulfide; and contaminated with polynuclear aromatic hydrocarbons (PAHs) and pentachlorophenol. Site 3 soil samples consisted of two separate subsamples, the first characterized as loamy with a relatively high TOC, MF, and sulfide content, and the second as a mixture of silty/clay and sand with relatively low TOC, MF, and sulfide content. Both sub-site samples were contaminated with heavy metals, including copper, lead, and zinc. FETAX (Frog Embryo Teratogenesis Assay -- Xenopus) testing of Site 1 samples indicated that substantially greater levels of developmental toxicity were induced by the aqueous extracts than the whole bulk soil. Tests with Site 2 samples suggested that both of the preparations were capable of inducing comparable rates of developmental toxicity. Tests with subsample a of Site 3 indicated that the aqueous extract of the sample induced greater levels of developmental toxicity than the whole soil.

  9. Modifications to particles as they move through landscapes: connecting soils and sediments

    NASA Astrophysics Data System (ADS)

    Owens, Philip N.

    2016-04-01

    In many areas of the world, soils are eroded leading to the movement of particles towards the global ocean. Along this journey, there are modifications to these particles and we tend to refer to this altered material as sediment in recognition that such material may no longer be fully reflective of its source. These modifications are brought about by physical, chemical and biological processes, and by the inclusion of additional sources of material, such as channel banks. The degree of modification is partly a function of the inherent properties of the original soil material but also reflects landscape type, and the temporal and spatial scales of investigation. This presentation will consider the changes in particles between soil profiles and sediment transported in river systems, drawing on examples from studies in Canada and beyond. It is hoped that by understanding the transformation of such material we can predict better its movement and impacts.

  10. Reductive microbial dechlorination of indigenous polychlorinated biphenyls in soil using a sediment-free inoculum

    SciTech Connect

    Klasson, K.T.; Barton, J.W.; Evans, B.S.; Reeves, M.E.

    1996-05-01

    In laboratory experiments, unagitated soil slurry bioreactors inoculated with microorganisms extracted from polychlorinated biphenyl-contaminated (PCBs) sediments from the Hudson River were used to anaerobically dechlorinate PCBs. The onset of dechlorination activity was accelerated by the addition of certain organic acids (pyruvate and maleate) and single congeners (2,3,6-trichlorobiphenyl). Dechlorination was observed under several working conditions after 19 weeks of incubation with PCB-contaminated soil and nutrient solution. Best results showed a drop in average chlorine content from 4.3 to 3.6 chlorines per biphenyl due to a loss of m-chlorines. Soil used for these experiments was obtained from a PCB-contaminated (weathered Aroclor 1248) site at an electric power substation. Dechlorination was observed with no sediment particles or other matrix being added. 17 refs., 6 figs., 1 tab.

  11. DEMONSTRATION BULLETIN: IN-SITU STEAM/HOT AIR SOIL STRIPPING TOXIC TREATMENT (USA) INC.

    EPA Science Inventory

    This technology uses steam and hot air to strip volatile organics from contaminated soil. The treatment equipment is mobile and treats the soil in-situ without need for soil excavation or transportation. The organic contaminants volatilized from the soil are condensed and col...

  12. TRANSFORMATION OF CHIRAL POLLUTANTS IN SOIL AND SEDIMENT MICROCOSMS

    EPA Science Inventory

    The transformation rates and enantiomeric ratios of several chiral pollutants were determined in laboratory microcosms (25oC). Aerobic and anaerobic agricultural soil slurries were separately dosed with the following chiral pesticides: o,p'-DDT, o,p'-methoxychlor, cis-chlordane, ...

  13. Column-centrifugation method for determining water retention curves of soils and disperse sediments

    NASA Astrophysics Data System (ADS)

    Smagin, A. V.

    2012-04-01

    A new instrumental method was proposed for the rapid estimation of the water-retention capacity of soils and sediments. The method is based on the use of a centrifugal field to remove water from distributed soil columns. In distinction from the classical method of high columns, the use of a centrifugal force field stronger than the gravity field allowed reducing the height of the soil samples from several meters to 10-20 cm (the typical size of centrifuge bags). In distinction from equilibrium centrifugation, the proposed method obtained an almost continuous water retention curve during the rotation of the soil column only at one-two centrifuge speeds. The procedure was simple in use, had high accuracy, and obtained reliable relationships between the capillary-sorption water potential and the soil water content in a wide range from the total water capacity to the wilting point.

  14. Fine Increment Soil Collector (FISC): A new device to support high resolution soil and sediment sampling for agri-environmental assessments

    NASA Astrophysics Data System (ADS)

    Mabit, Lionel; Meusburger, Katrin; Iurian, Andra-Rada; Owens, Philip N.; Toloza, Arsenio; Alewell, Christine

    2014-05-01

    Soil and sediment related research for terrestrial agri-environmental assessments requires accurate depth incremental sampling of soil and exposed sediment profiles. Existing coring equipment does not allow collecting soil/sediment increments at millimetre resolution. Therefore, the authors have designed an economic, portable, hand-operated surface soil/sediment sampler - the Fine Increment Soil Collector (FISC) - which allows extensive control of soil/sediment sampling process and easy recovery of the material collected by using a simple screw-thread extraction system. In comparison with existing sampling tools, the FISC has the following advantages and benefits: (i) it permits sampling of soil/sediment samples at the top of the profile; (ii) it is easy to adjust so as to collect soil/sediment at mm resolution; (iii) it is simple to operate by one single person; (iv) incremental samples can be performed in the field or at the laboratory; (v) it permits precise evaluation of bulk density at millimetre vertical resolution; and (vi) sample size can be tailored to analytical requirements. To illustrate the usefulness of the FISC in sampling soil and sediments for 7Be - a well-known cosmogenic soil tracer and fingerprinting tool - measurements, the sampler was tested in a forested soil located 45 km southeast of Vienna in Austria. The fine resolution increments of 7Be (i.e. 2.5 mm) affects directly the measurement of the 7Be total inventory but above all impacts the shape of the 7Be exponential profile which is needed to assess soil movement rates. The FISC can improve the determination of the depth distributions of other Fallout Radionuclides (FRN) - such as 137Cs, 210Pbexand239+240Pu - which are frequently used for soil erosion and sediment transport studies and/or sediment fingerprinting. Such a device also offers great potential to investigate FRN depth distributions associated with fallout events such as that associated with nuclear emergencies. Furthermore, prior

  15. Solar Park Impacts on Air and Soil Microclimate

    NASA Astrophysics Data System (ADS)

    Armstrong, A.; Ostle, N. J.; Whitaker, J.

    2015-12-01

    The drive towards low carbon energy sources and increasing energy demand has resulted in a rapid rise in solar photovoltaics across the world. A substantial proportion of photovoltaics are large-scale ground-mounted systems, solar parks, causing a notable land use change. While the impacts of photovoltaic panel production and disposal have been considered, the consequences of the operation of solar parks on the hosting landscape are poorly resolved. Here, we present data which demonstrates that a solar park sited on permanent grassland in the UK significantly impacted the air and soil microclimate. Specifically, we observed (1) cooler soil under the photovoltaic panels during the summer and between the photovoltaic panel rows during the winter; (2) dampening of the diurnal variation in air temperature and absolute humidity from the spring to the autumn; (3) lower photosynthetically active radiation and a lower direct:diffuse under the panels; and (4) reduced wind speed between the panel rows and substantially reduced wind speeds under the panels. Further, there were differences in vegetation type and productivity and greenhouse gas emissions. Given the centrality of climate on ecosystem function, quantifying the microclimatic impacts of this emerging land use change is critical. We anticipate these data will help develop understanding of effects in other climates, under different solar park designs and the implications for the function and service provision of the hosting landscape.

  16. Environmental application of nanotechnology: air, soil, and water.

    PubMed

    Ibrahim, Rusul Khaleel; Hayyan, Maan; AlSaadi, Mohammed Abdulhakim; Hayyan, Adeeb; Ibrahim, Shaliza

    2016-07-01

    Global deterioration of water, soil, and atmosphere by the release of toxic chemicals from the ongoing anthropogenic activities is becoming a serious problem throughout the world. This poses numerous issues relevant to ecosystem and human health that intensify the application challenges of conventional treatment technologies. Therefore, this review sheds the light on the recent progresses in nanotechnology and its vital role to encompass the imperative demand to monitor and treat the emerging hazardous wastes with lower cost, less energy, as well as higher efficiency. Essentially, the key aspects of this account are to briefly outline the advantages of nanotechnology over conventional treatment technologies and to relevantly highlight the treatment applications of some nanomaterials (e.g., carbon-based nanoparticles, antibacterial nanoparticles, and metal oxide nanoparticles) in the following environments: (1) air (treatment of greenhouse gases, volatile organic compounds, and bioaerosols via adsorption, photocatalytic degradation, thermal decomposition, and air filtration processes), (2) soil (application of nanomaterials as amendment agents for phytoremediation processes and utilization of stabilizers to enhance their performance), and (3) water (removal of organic pollutants, heavy metals, pathogens through adsorption, membrane processes, photocatalysis, and disinfection processes).

  17. Chemical-Specific Representation of Air-Soil Exchange and Soil Penetration in Regional Multimedia Models

    SciTech Connect

    McKone, T.E.; Bennett, D.H.

    2002-08-01

    In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and multiple transformation processes. They also provide an explicit quantification of the characteristic soil penetration depth. We construct a compartment model using three and four soil layers to replicate with high reliability the flux and mass distribution obtained from the exact analytical solution describing the transient dispersion, advection, and transformation of chemicals in soil with fixed properties and boundary conditions. Unlike the analytical solution, which requires fixed boundary conditions, the soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, ground water, surface water) in multimedia fate models. We demonstrate and evaluate the performance of the algorithms in a model with applications to benzene, benzo(a)pyrene, MTBE, TCDD, and tritium.

  18. Natural radioactivity content in soil and indoor air of Chellanam.

    PubMed

    Mathew, S; Rajagopalan, M; Abraham, J P; Balakrishnan, D; Umadevi, A G

    2012-11-01

    Contribution of terrestrial radiation due to the presence of naturally occurring radionuclides in soil and air constitutes a significant component of the background radiation exposure to the population. The concentrations of natural radionuclides in the soil and indoor air of Chellanam were investigated with an aim of evaluating the environmental radioactivity level and radiation hazard to the population. Chellanam is in the suburbs of Cochin, with the Arabian Sea in the west and the Cochin backwaters in the east. Chellanam is situated at ∼25 km from the sites of these factories. The data obtained serve as a reference in documenting changes to the environmental radioactivity due to technical activities. Soil samples were collected from 30 locations of the study area. The activity concentrations of (232)Th, (238)U and (40)K in the samples were analysed using gamma spectrometry. The gamma dose rates were calculated using conversion factors recommended by UNSCEAR [United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation. UNSCEAR (2000)]. The ambient radiation exposure rates measured in the area ranged from 74 to 195 nGy h(-1) with a mean value of 131 nGy h(-1). The significant radionuclides being (232)Th, (238)U and (40)K, their activities were used to arrive at the absorbed gamma dose rate with a mean value of 131 nGy h(-1) and the radium equivalent activity with a mean value of 162 Bq kg(-1). The radon progeny levels varied from 0.21 to 1.4 mWL with a mean value of 0.6 mWL. The thoron progeny varied from 0.34 to 2.9 mWL with a mean value of 0.85 mWL. The ratio between thoron and radon progenies varied from 1.4 to 2.3 with a mean of 1.6. The details of the study, analysis and results are discussed.

  19. Trace metals in the coastal soils developed from estuarine floodplain sediments in the Croatian Mediterranean region.

    PubMed

    Romic, D; Romic, M; Zovko, M; Bakic, H; Ondrasek, G

    2012-08-01

    Fertile soils in the River Neretva estuary were developed by fluvial sedimentation and deposition of the eroded soil material from the karst hills within the catchment. After extensive reclamation, two reclaimed land zones (fluvial terraces and lower-laying terraces) have been delineated, both used for agriculture. The main objectives of this study were to evaluate soil chemical and geochemical properties in reclaimed zones that differ mainly in topography, soil types and agricultural land use. The origin of the trace metals in the arable soils was studied using multivariate statistics, and interpolation maps of trace metals were produced using GIS and geostatistics. Soil trace metal concentrations do not exceed a threshold value established by the Croatian Government regulation, with exception of copper. Comparative analysis of the main soil properties and trace metal concentrations in the study area showed a pronounced spatial variation and differences between two reclaimed zones in soil organic matter content, bioavailable P and total concentrations of Cd and Cu. Factor analysis in the area of the lower-laying terraces showed grouping of bioavailable P and K, organic matter content and pH (negative loading) in the component associated mostly with the land use. In the area of the fluvial terraces, bioavailable P and total Cd were grouped in the same component that may be explained by the traditional small farm agriculture and overuse of mineral fertilizers. In the whole study area, processes of secondary salinization were determined, accompanied by the raised chloride and sodium concentration measured in the saturation soil extract.

  20. Air-Seawater Exchange of Organochlorine Pesticides along the Sediment Plume of a Large Contaminated River.

    PubMed

    Lin, Tian; Guo, Zhigang; Li, Yuanyuan; Nizzetto, Luca; Ma, Chuanliang; Chen, Yingjun

    2015-05-01

    Gaseous exchange fluxes of organochlorine pesticides (OCPs) across the air-water interface of the coastal East China Sea were determined in order to assess whether the contaminated plume of the Yangtze River could be an important regional source of OCPs to the atmosphere. Hexachlorocyclohexanes (HCHs), chlordane compounds (CHLs), and dichlorodiphenyltrichloroethanes (DDTs) were the most frequently detected OCPs in air and water. Air-water exchange was mainly characterized by net volatilization for all measured OCPs. The net gaseous exchange flux ranged 10-240 ng/(m2·day) for γ-HCH, 60-370 ng/(m2·day) for trans-CHL, 97-410 ng/(m2·day) for cis-CHL, and ∼0 (e.g., equilibrium) to 490 ng/(m2·day) for p,p'-DDE. We found that the plume of the large contaminated river can serve as a significant regional secondary atmospheric source of legacy contaminants released in the catchment. In particular, the sediment plume represented the relevant source of DDT compounds (especially p,p'-DDE) sustaining net degassing when clean air masses from the open ocean reached the plume area. In contrast, a mass balance showed that, for HCHs, contaminated river discharge (water and sediment) plumes were capable of sustaining volatilization throughout the year. These results demonstrate the inconsistencies in the fate of HCHs and DDTs in this large estuarine system with declining primary sources.

  1. Sediment budget for Murder Creek, Georgia, USA, from Pu239+240 - determined soil erosion rates

    NASA Astrophysics Data System (ADS)

    Stubblefield, A. P.; Matissoff, G.; Ketterer, M. E.; Whiting, P. J.

    2005-12-01

    Soil inventories of the radionuclides Cs137 and Pb210 have been used in a variety of environments as indicators for erosion and depositional processes. Development of sediment budgets for entire watersheds from radionuclide data has been somewhat constrained because limited sample numbers may not adequately characterize the wide range of geomorphic conditions and land uses found in heterogeneous environments. The measurement of Pu239+240 shows great potential for developing quantitative watershed sediment budgets. With inductively-coupled plasma mass spectrometry, hundreds of samples may be processed in dramatically shorter times than the gamma spectrometry method used for Cs137 or alpha spectrometry method used for Pb210. We collected surface soil samples from Murder Creek in the Piedmont region of Georgia, USA, to compare Pu239+240 inventories with Cs137 and Pb210 inventories for a range of land uses in a predominantly forested watershed. Excellent correlations were found for radionuclide inventories (r2 =0.88, n = 38) and high resolution (4 mm) depth profiles. The second objective was to generate a sediment budget using the full Pu239+240 dataset (n = 309). Average Pu239+240 inventories were 70.0 Bq/m2 for hardwood forest, 60.0 Bq/m2 for pine plantation, 65.1 Bq/m2 for pine forest, 66.7 Bq/m2 for row crop agriculture and 67.9 Bq/m2 for pasture. The sediment budget will be constructed by converting inventories into site-specific erosion rates. Erosion rates will be scaled up to the watershed scale using GIS coverages of land use, soil, slope, and slope position. Results will be compared with Murder Creek sediment budgets in the scientific literature generated from RUSLE erosion modeling, USGS monitoring networks and reservoir sedimentation.

  2. Disposal of dredged sediments in tropical soils: ecotoxicological effects on earthworms.

    PubMed

    Cesar, Ricardo; Natal-da-Luz, Tiago; Sousa, José Paulo; Colonese, Juan; Bidone, Edison; Castilhos, Zuleica; Egler, Silvia; Polivanov, Helena

    2014-03-01

    The upper limit concentrations of metals established by international legislations for dredged sediment disposal and soil quality do not take into consideration the properties of tropical soils (generally submitted to more intense weathering processes) on metal availability and ecotoxicity. Aiming to perform an evaluation on the suitability of these threshold values in tropical regions, the ecotoxicity of metal-contaminated dredged sediment from the Guanabara Bay (Rio de Janeiro, Brazil) was investigated. Acute and avoidance tests with Eisenia andrei were performed with mixtures of dredged sediment with a ferralsol (0.00, 6.66, 13.12, 19.98, and 33.30 %) and a chernosol (0.00, 6.58, 13.16, 19.74, and 32.90 %). Mercury, lead, nickel, chromium, copper, and zinc concentrations were measured in test mixtures and in tissues of surviving earthworms from the acute tests. While ferralsol test mixtures provoked significant earthworm avoidance response at concentrations ≥13.31 %, the chernosol mixtures showed significant avoidance behavior only at the 19.74 % concentration. The acute tests showed higher toxicity in ferralsol mixtures (LC50 = 9.9 %) compared to chernosol mixtures (LC50 = 16.5 %), and biomass increased at the lowest sediment doses in treatments of both test soils. Most probably, the expansive clay minerals present in chernosol contributed to reduce metal availability in chernosol mixtures, and consequently, the ecotoxicity of these treatments. The bioconcentration factors (BCF) for zinc and copper were lower with increasing concentrations of the dredged sediment, indicating the existence of internal regulating processes. Although the BCF for mercury also decreased with the increasing test concentrations, the known no biological function of this metal in the earthworms metabolism lead to suppose that Hg measured was not present in bioaccumulable forms. BCFs estimated for the other metals were generally higher in the highest dredged sediment doses

  3. Flow Cytometric Assessment of Bacterial Abundance in Soils, Sediments and Sludge.

    PubMed

    Frossard, Aline; Hammes, Frederik; Gessner, Mark O

    2016-01-01

    Bacterial abundance is a fundamental measure in microbiology, but its assessment is often tedious, especially for soil, and sediment samples. To overcome this limitation, we adopted a time-efficient flow-cytometric (FCM) counting method involving cell detachment and separation from matrix particles by centrifugation in tubes receiving sample suspensions and Histodenz(®) solution. We used this approach to assess bacterial abundances in diverse soils (natural and agricultural), sediments (streams and lakes) and sludge from sand-filters in a drinking water treatment plant and compared the results to bacterial abundances determined by two established methods, epifluorescence microscopy (EM) and adenosine triphosphate (ATP) quantification. Cell abundances determined by FCM and EM correlated fairly well, although absolute cell abundances were generally lower when determined by FCM. FCM also showed significant relations with cell counts converted from ATP concentrations, although estimates derived from ATP determinations were typically higher, indicating the presence of ATP sources other than bacteria. Soil and sediment organic matter (OM) content influenced the goodness of fit between counts obtained with EM and FCM. In particular, bacterial abundance determined by FCM in samples containing less than 10% OM, such as stream sediment, was particularly well correlated with the cell counts assessed by EM. Overall, these results suggest that FCM following cell detachment and purification is a useful approach to increase sample throughput for determining bacterial abundances in soils, sediments and sludge. However, notable scatter and only partial concordance among the FCM and reference methods suggests that protocols require further improvement for assessments requiring high precision, especially when OM contents in samples are high.

  4. Soil and sediments micromorphology: reconstruction of palaeoenvironments, anthropogenic processes, or more recent human impact on ecosystems

    NASA Astrophysics Data System (ADS)

    Gérard, Martine; Trombino, Luca; Stoops, Georges

    2014-05-01

    Soils and sediments registered the environmental changes in time and space, but also display components inherited from human activities, both in archaeological and in modern times. Micromorphological investigations carried out on undisturbed samples of soil and sediments by microscopic and ultramicroscopic techniques, correlated with mineralogy, geochemistry or biology, allow us to interpret the processes behind the formation of regoliths, sediments and anthropogenic deposits, from which a relative chronology, specific environmental conditions and/or extent of human impact may be deduced. The traditional optical microscopy observations, carried on the thin section groundmass and pedofeatures, provide clues on the different processes behind soils and sediments genesis (weathering, supergene, low T hydrothermal, anthropogenic) and their impact on ecosystems or on palaeoenvironments. In more recent times, the improvements in electron microscope imaging technology permit to make detailed observations up to the nanoscale, opening a new domain of observations to micromorphologists, both as regard of the micromass and of the thinner pedofeatures. Moreover, the optimisation of the microgeochemical mapping techniques, with spatially resolved chemical, isotopic or mineralogical analyses, is another powerful tool to gain insight in chemical migration fronts: the limit of the original rock fabric disappearance may be bypassed. In order to illustrate micromorphological researches in natural and man-influenced ecosystems, and to combine researches at different scales, several optical and electronic images of soils and sediments groundmass, associated to their microgeochemical characteristics will be presented, with selected examples taken from the climatic record of paleosols, the impact of hydrothermal alteration on saprolites, the neo-formation of minerals related to weathering process evolution, the protosoil formation in natural and human waste deposits, and the forensic

  5. Flow Cytometric Assessment of Bacterial Abundance in Soils, Sediments and Sludge

    PubMed Central

    Frossard, Aline; Hammes, Frederik; Gessner, Mark O.

    2016-01-01

    Bacterial abundance is a fundamental measure in microbiology, but its assessment is often tedious, especially for soil, and sediment samples. To overcome this limitation, we adopted a time-efficient flow-cytometric (FCM) counting method involving cell detachment and separation from matrix particles by centrifugation in tubes receiving sample suspensions and Histodenz® solution. We used this approach to assess bacterial abundances in diverse soils (natural and agricultural), sediments (streams and lakes) and sludge from sand-filters in a drinking water treatment plant and compared the results to bacterial abundances determined by two established methods, epifluorescence microscopy (EM) and adenosine triphosphate (ATP) quantification. Cell abundances determined by FCM and EM correlated fairly well, although absolute cell abundances were generally lower when determined by FCM. FCM also showed significant relations with cell counts converted from ATP concentrations, although estimates derived from ATP determinations were typically higher, indicating the presence of ATP sources other than bacteria. Soil and sediment organic matter (OM) content influenced the goodness of fit between counts obtained with EM and FCM. In particular, bacterial abundance determined by FCM in samples containing less than 10% OM, such as stream sediment, was particularly well correlated with the cell counts assessed by EM. Overall, these results suggest that FCM following cell detachment and purification is a useful approach to increase sample throughput for determining bacterial abundances in soils, sediments and sludge. However, notable scatter and only partial concordance among the FCM and reference methods suggests that protocols require further improvement for assessments requiring high precision, especially when OM contents in samples are high. PMID:27379043

  6. Flow Cytometric Assessment of Bacterial Abundance in Soils, Sediments and Sludge.

    PubMed

    Frossard, Aline; Hammes, Frederik; Gessner, Mark O

    2016-01-01

    Bacterial abundance is a fundamental measure in microbiology, but its assessment is often tedious, especially for soil, and sediment samples. To overcome this limitation, we adopted a time-efficient flow-cytometric (FCM) counting method involving cell detachment and separation from matrix particles by centrifugation in tubes receiving sample suspensions and Histodenz(®) solution. We used this approach to assess bacterial abundances in diverse soils (natural and agricultural), sediments (streams and lakes) and sludge from sand-filters in a drinking water treatment plant and compared the results to bacterial abundances determined by two established methods, epifluorescence microscopy (EM) and adenosine triphosphate (ATP) quantification. Cell abundances determined by FCM and EM correlated fairly well, although absolute cell abundances were generally lower when determined by FCM. FCM also showed significant relations with cell counts converted from ATP concentrations, although estimates derived from ATP determinations were typically higher, indicating the presence of ATP sources other than bacteria. Soil and sediment organic matter (OM) content influenced the goodness of fit between counts obtained with EM and FCM. In particular, bacterial abundance determined by FCM in samples containing less than 10% OM, such as stream sediment, was particularly well correlated with the cell counts assessed by EM. Overall, these results suggest that FCM following cell detachment and purification is a useful approach to increase sample throughput for determining bacterial abundances in soils, sediments and sludge. However, notable scatter and only partial concordance among the FCM and reference methods suggests that protocols require further improvement for assessments requiring high precision, especially when OM contents in samples are high. PMID:27379043

  7. Soil erosion and sediment yield and their relationships with vegetation cover in upper stream of the Yellow River.

    PubMed

    Ouyang, Wei; Hao, Fanghua; Skidmore, Andrew K; Toxopeus, A G

    2010-12-15

    Soil erosion is a significant concern when considering regional environmental protection, especially in the Yellow River Basin in China. This study evaluated the temporal-spatial interaction of land cover status with soil erosion characteristics in the Longliu Catchment of China, using the Soil and Water Assessment Tool (SWAT) model. SWAT is a physical hydrological model which uses the RUSLE equation as a sediment algorithm. Considering the spatial and temporal scale of the relationship between soil erosion and sediment yield, simulations were undertaken at monthly and annual temporal scales and basin and sub-basin spatial scales. The corresponding temporal and spatial Normalized Difference Vegetation Index (NDVI) information was summarized from MODIS data, which can integrate regional land cover and climatic features. The SWAT simulation revealed that the annual soil erosion and sediment yield showed similar spatial distribution patterns, but the monthly variation fluctuated significantly. The monthly basin soil erosion varied from almost no erosion load to 3.92 t/ha and the maximum monthly sediment yield was 47,540 tones. The inter-annual simulation focused on the spatial difference and relationship with the corresponding vegetation NDVI value for every sub-basin. It is concluded that, for this continental monsoon climate basin, the higher NDVI vegetation zones prevented sediment transport, but at the same time they also contributed considerable soil erosion. The monthly basin soil erosion and sediment yield both correlated with NDVI, and the determination coefficients of their exponential correlation model were 0.446 and 0.426, respectively. The relationships between soil erosion and sediment yield with vegetation NDVI indicated that the vegetation status has a significant impact on sediment formation and transport. The findings can be used to develop soil erosion conservation programs for the study area.

  8. Characterization and mobility of geogenic chromium in soils and river bed sediments of Asopos basin.

    PubMed

    Lilli, Maria A; Moraetis, Daniel; Nikolaidis, Nikolaos P; Karatzas, George P; Kalogerakis, Nicolas

    2015-01-01

    A field and laboratory study was conducted to assess the origin and mobility of CrVI in Asopos basin in Greece. Sampling was designed in such way as to capture the spatial variability of chromium occurring in sediments and soils in different lithological units in the area. Physicochemical and geochemical characterization of surface agricultural soils obtained from river terraces and river bed sediments was conducted in order to determine the natural background of chromium. Lithologies with strong calcareous, siliceous and ultramafic components were identified using principal component analysis. Laboratory mobility studies quantified the rates of chromium sorption and release from soils and their capacity to adsorb chromium. Heavy metal analysis and local geology study support the hypothesis that the main source of chromium is of geogenic origin. Chromium distribution in Asopos river bed was influenced from the eroded products derived from extensive areas with ultramafic rocks the last 5Ma. The mobility studies showed that leaching process was very fast and sorption capacity was significant and capable to retain chromium in case of waste release in the river. Finally the mobility of chromium release is limited due to existing attenuation capacity controlled by ferric oxides coatings on the soil and sediments.

  9. Analysis of sulfonamides in soil, sediment, and sludge based on dynamic microwave-assisted micellar extraction.

    PubMed

    Wang, Hui; Ding, Jie; Ding, Lan; Ren, Nanqi

    2016-07-01

    A green and high-throughput analytical method was described for the simultaneous determination of ten sulfonamides (SAs) from soil, sediment, and sludge in northeast China. None of potentially hazardous organic solvents was used in the whole sample preparation procedure, and the total preparation time of 15 samples was about 18 min. The limits of detection for the SAs were in the range of 0.42-0.68 ng g(-1). The intra-day and inter-day precisions, expressed by the relative standard deviation, were below 7 %. Under the optimum conditions, the recoveries of ten SAs were between 69.7 and 102.7 %. The proposed method was successfully applied to analyze the SAs residues in agricultural soils, river sediments, and sewage sludge. SAs were found at the levels of 1.40-2.31 ng g(-1) and 3.77-29.29 ng g(-1) in the sediments and sludge, respectively. The aging effect of spiked soil samples on the SAs recoveries was examined, and the results demonstrate that eight SAs could persist in five soils for 3 months. Compared with the traditional method, the proposed method could reduce the consumption of the organic solvent, shorten the sample preparation time, and increase the sample throughput.

  10. Sorption and dissipation of testosterone, estrogens, and their primary transformation products in soils and sediment.

    PubMed

    Lee, Linda S; Strock, Troy J; Sarmah, Ajit K; Rao, P Suresh C

    2003-09-15

    Concern over the potential negative ecological effects of steroid hormones from human- and animal-derived wastes has resulted in an increased interest regarding the mobility and persistence of these compounds in the environment. Batch experiments were conducted to examine the simultaneous sorption and dissipation of three reproductive hormones (testosterone, 17beta-estradiol, and 17alpha-ethynyl estradiol) in four midwestern U.S. soils and one freshwater sediment. Sorption isotherms were generated by measuring aqueous concentrations and by extracting the sorbed parent chemical or transformation products (e.g., estrone, androstenedione). Apparent sorption equilibrium is reached within a few hours. Measured sorption isotherms for the three parent chemicals and their principal transformation products were generally linear. Average organic carbon normalized sorption coefficients (K(oc)) resulted in standard deviations of less than 0.2 log units and were consistent with reported aqueous solubilites and octanol-water partition coefficients, indicating hydrophobic partitioning as the dominant sorption mechanism. Large log K(oc) values (approximately 3-4) suggest that leaching from soils will be limited, runoff of soil- and land-applied biosolids are the most likely inputs into surface waters, and that a significant fraction of these compounds will be associated with sediments. Half-lives for hormone dissipation in the aerobic soil and sediment slurries estimated assuming pseudo first-order processes ranged from a few hours to a few days with testosterone having the shortest half-life.

  11. Dissolution characteristics of Pu-contaminated soils and sediments in lung serum simulant solution.

    PubMed

    Lee, S Y; Bondietti, E A; Tamura, T

    1982-11-01

    Dissolution characteristics of Pu from contaminated Nevada Test Site (NTS) and Rocky Flats (RF) soils, and Mound Laboratory (ML) and Oak Ridge National Laboratory (ORNL) sediments in lung serum simulant solution at 37 degrees C were investigated. The dissolved Pu concentration had reached a maximum within a day of equilibration and the percent dissolved Pu at the maximum was 0.70 (RF), 0.43 (ML), 0.02 (ORNL), and 0.02 (NTS). The Pu concentrations of the RF, ML and ORNL samples in the successively extracted solutions decreased drastically but the concentration in the NTS soil extracts did not change significantly. The differences in Pu dissolution among the samples were caused by the differences in the total Pu concentration, particle size distribution, and chemical nature of Pu in contaminated soils and sediments. The higher solubility of the particulate Pu form in the RF soil relative to the ORNL sediment contaminated by dissolved Pu suggests that contamination source alone can not explain the observed differences. Variation of Pu solubility among the samples indicates that a single solubility class for dose assessment use may not be appropriate, particularly if one attempts to make comparative assessments among different sites. PMID:7152928

  12. Immobilization of mercury in field soil and sediment using carboxymethyl cellulose stabilized iron sulfide nanoparticles.

    PubMed

    Gong, Yanyan; Liu, Yuanyuan; Xiong, Zhong; Kaback, Dawn; Zhao, Dongye

    2012-07-27

    Mercury (Hg) is one of the most pervasive and bio-accumulative metals in the environment. Yet, effective in situ remediation technologies have been lacking. This study investigated the effectiveness of a class of soil-deliverable FeS nanoparticles for in situ immobilization of Hg in two field-contaminated soils from a New Jersey site and one sediment from an Alabama site. The nanoparticles were prepared using sodium carboxymethyl cellulose (CMC) as a stabilizer. Transmission electron microscopy measurements revealed a particle size of 34.3 ± 8.3 nm (standard deviation), whereas dynamic light scattering gave a hydrodynamic diameter of 222.5 ± 3.2 nm. Batch tests showed that at an FeS-to-Hg molar ratio of 28:1-118:1, the nanoparticles reduced water-leachable Hg by 79%-96% and the TCLP (toxicity characteristic leaching procedure) based leachability by 26%-96%. Column breakthrough tests indicated that the nanoparticles were deliverable in the sediment/soil columns under moderate injection pressure. However, once the external pressure was removed, the delivered nanoparticles remained virtually mobile under typical groundwater flow conditions. When the Hg-contaminated soil and sediment were treated with 52-95 pore volumes of a 500 mg l(-1) FeS nanoparticle suspension, water-leachable Hg was reduced by 90%-93% and TCLP-leachable Hg was reduced by 65%-91%. The results warrant further field demonstration of this promising in situ remediation technology.

  13. Trace metal behaviour in estuarine and riverine floodplain soils and sediments: a review.

    PubMed

    Du Laing, G; Rinklebe, J; Vandecasteele, B; Meers, E; Tack, F M G

    2009-06-15

    This paper reviews the factors affecting trace metal behaviour in estuarine and riverine floodplain soils and sediments. Spatial occurrence of processes affecting metal mobility and availability in floodplains are largely determined by the topography. At the oxic-anoxic interface and in the anoxic layers of floodplain soils, especially redox-sensitive processes occur, which mainly result in the inclusion of metals in precipitates or the dissolution of metal-containing precipitates. Kinetics of these processes are of great importance for these soils as the location of the oxic-anoxic interface is subject to change due to fluctuating water table levels. Other important processes and factors affecting metal mobility in floodplain soils are adsorption/desorption processes, salinity, the presence of organic matter, sulphur and carbonates, pH and plant growth. Many authors report highly significant correlations between cation exchange capacity, clay or organic matter contents and metal contents in floodplain soils. Iron and manganese (hydr)oxides were found to be the main carriers for Cd, Zn and Ni under oxic conditions, whereas the organic fraction was most important for Cu. The mobility and availability of metals in a floodplain soil can be significantly reduced by the formation of metal sulphide precipitates under anoxic conditions. Ascending salinity in the flood water promotes metal desorption from the floodplain soil in the absence of sulphides, hence increases total metal concentrations in the water column. The net effect of the presence of organic matter can either be a decrease or an increase in metal mobility, whereas the presence of carbonates in calcareous floodplain soils or sediments constitutes an effective buffer against a pH decrease. Moreover, carbonates may also directly precipitate metals. Plants can affect the metal mobility in floodplain soils by oxidising their rhizosphere, taking up metals, excreting exudates and stimulating the activity of

  14. Potential Carbon Transport: Linking Soil Aggregate Stability and Sediment Enrichment for Updating the Soil Active Layer within Intensely Managed Landscapes

    NASA Astrophysics Data System (ADS)

    Wacha, K.; Papanicolaou, T.; Abban, B. K.; Wilson, C. G.

    2014-12-01

    Currently, many biogeochemical models lack the mechanistic capacity to accurately simulate soil organic carbon (SOC) dynamics, especially within intensely managed landscapes (IMLs) such as those found in the U.S. Midwest. These modeling limitations originate by not accounting for downslope connectivity of flowpathways initiated and governed by landscape processes and hydrologic forcing, which induce dynamic updates to the soil active layer (generally top 20-30cm of soil) with various sediment size fractions and aggregates being transported and deposited along the downslope. These hydro-geomorphic processes, often amplified in IMLs by tillage events and seasonal canopy, can greatly impact biogeochemical cycles (e.g., enhanced mineralization during aggregate breakdown) and in turn, have huge implications/uncertainty when determining SOC budgets. In this study, some of these limitations were addressed through a new concept, Potential Carbon Transport (PCT), a term which quantifies a maximum amount of material available for transport at various positions of the landscape, which was used to further refine a coupled modeling framework focused on SOC redistribution through downslope/lateral connectivity. Specifically, the size fractions slaked from large and small aggregates during raindrop-induced aggregate stability tests were used in conjunction with rainfall-simulated sediment enrichment ratio (ER) experiments to quantify the PCT under various management practices, soil types and landscape positions. Field samples used in determining aggregate stability and the ER experiments were collected/performed within the historic Clear Creek Watershed, home of the IML Critical Zone Observatory, located in Southeastern Iowa.

  15. Spatio-temporal patterns of soil erosion and suspended sediment dynamics in the Mekong River Basin.

    PubMed

    Suif, Zuliziana; Fleifle, Amr; Yoshimura, Chihiro; Saavedra, Oliver

    2016-10-15

    Understanding of the distribution patterns of sediment erosion, concentration and transport in river basins is critically important as sediment plays a major role in river basin hydrophysical and ecological processes. In this study, we proposed an integrated framework for the assessment of sediment dynamics, including soil erosion (SE), suspended sediment load (SSL) and suspended sediment concentration (SSC), and applied this framework to the Mekong River Basin. The Revised Universal Soil Loss Equation (RUSLE) model was adopted with a geographic information system to assess SE and was coupled with a sediment accumulation and a routing scheme to simulate SSL. This framework also analyzed Landsat imagery captured between 1987 and 2000 together with ground observations to interpolate spatio-temporal patterns of SSC. The simulated SSL results from 1987 to 2000 showed the relative root mean square error of 41% and coefficient of determination (R(2)) of 0.89. The polynomial relationship of the near infrared exoatmospheric reflectance and the band 4 wavelength (760-900nm) to the observed SSC at 9 sites demonstrated the good agreement (overall relative RMSE=5.2%, R(2)=0.87). The result found that the severe SE occurs in the upper (China and Lao PDR) and lower (western part of Vietnam) regions. The SSC in the rainy season (June-November) showed increasing and decreasing trends longitudinally in the upper (China and Lao PDR) and lower regions (Cambodia), respectively, while the longitudinal profile of SSL showed a fluctuating trend along the river in the early rainy season. Overall, the results described the unique spatio-temporal patterns of SE, SSL and SSC in the Mekong River Basin. Thus, the proposed integrated framework is useful for elucidating complex process of sediment generation and transport in the land and river systems of large river basins.

  16. Spatio-temporal patterns of soil erosion and suspended sediment dynamics in the Mekong River Basin.

    PubMed

    Suif, Zuliziana; Fleifle, Amr; Yoshimura, Chihiro; Saavedra, Oliver

    2016-10-15

    Understanding of the distribution patterns of sediment erosion, concentration and transport in river basins is critically important as sediment plays a major role in river basin hydrophysical and ecological processes. In this study, we proposed an integrated framework for the assessment of sediment dynamics, including soil erosion (SE), suspended sediment load (SSL) and suspended sediment concentration (SSC), and applied this framework to the Mekong River Basin. The Revised Universal Soil Loss Equation (RUSLE) model was adopted with a geographic information system to assess SE and was coupled with a sediment accumulation and a routing scheme to simulate SSL. This framework also analyzed Landsat imagery captured between 1987 and 2000 together with ground observations to interpolate spatio-temporal patterns of SSC. The simulated SSL results from 1987 to 2000 showed the relative root mean square error of 41% and coefficient of determination (R(2)) of 0.89. The polynomial relationship of the near infrared exoatmospheric reflectance and the band 4 wavelength (760-900nm) to the observed SSC at 9 sites demonstrated the good agreement (overall relative RMSE=5.2%, R(2)=0.87). The result found that the severe SE occurs in the upper (China and Lao PDR) and lower (western part of Vietnam) regions. The SSC in the rainy season (June-November) showed increasing and decreasing trends longitudinally in the upper (China and Lao PDR) and lower regions (Cambodia), respectively, while the longitudinal profile of SSL showed a fluctuating trend along the river in the early rainy season. Overall, the results described the unique spatio-temporal patterns of SE, SSL and SSC in the Mekong River Basin. Thus, the proposed integrated framework is useful for elucidating complex process of sediment generation and transport in the land and river systems of large river basins. PMID:27338846

  17. Calculated and Measured Air and Soil Freeze-Thaw Frequencies.

    NASA Astrophysics Data System (ADS)

    Baker, Donald G.; Ruschy, David L.

    1995-10-01

    Freeze-thaw frequencies calculated by eight different counting methods were compared using daily maximum and minimum temperatures from eight north-central United States National Weather Service (NWS) stations. These frequencies were also compared to those obtained using hourly air temperature data from six of the same NWS stations. In addition, the calculated frequencies were compared to measured freeze-thaw frequencies at several depths in a bare soil and a sod-covered soil at the University of Minnesota St. Paul campus climatological observatory.The necessary acceptance of the idealized daily heating cycle when using daily maximum and minimum air temperature data resulted in a higher occurrence of calculated freeze-thaw events than those obtained with hourly data; one method gave 23% more freeze-thaw events with the daily maximum and minimum temperatures.With the freeze-thaw phenomenon centered upon those months in which the mean temperature hovers near O°C, a bimodal frequency occurs at the northern stations (October and April, as at International Falls, Minnesota, and November and March at Fargo, North Dakota), while in warmer climates the bimodal characteristic is replaced by a single-peak frequency in January as at Sedalia and West Plains, Missouri.In the comparison between the calculated freeze-thaw frequencies based on daily maximum and minimum values and the hourly temperature measurements at several heights between the surface and the temperature shelter at the climatological observatory, it was found that the annual total frequencies increased as the height above the surface decreased. For the shallowest height above the surface there was an approximate 13% increase over those measured in the shelter with hourly temperature data.The annual total frequencies of the calculated freeze-thaw events obtained with the daily maximum and minimum temperature measurements in the shelter approximated those actually occurring at the 1-cm depth in a bare soil at the

  18. Degradation of the herbicide dichlobenil and its metabolite BAM in soils and subsurface sediments.

    PubMed

    Clausen, Liselotte; Arildskov, Niels P; Larsen, Flemming; Aamand, Jens; Albrechtsen, Hans-Jørgen

    2007-01-30

    The worldwide used herbicide dichlobenil (2,6-dichlorobenzonitrile) has resulted in widespread presence of its metabolite 2,6-dichlorobenzamide (BAM) in surface water and groundwater. To evaluate the potential for natural attenuation of this BAM pollution in groundwater, we studied the degradation of BAM and dichlobenil in 16 samples of clayey till, unconsolidated sand and limestone, including sediments from both oxidized and reduced conditions. The degradation of dichlobenil occurred primarily in the upper few meters below surface, although dichlobenil was strongly sorbed to these sediments. However, the degradation of dichlobenil to BAM could not be correlated to either sorption, water chemistry, composition of soils or sediments. Degradation of dichlobenil to BAM was limited (<2% degraded) in the deeper unsaturated zones, and no degradation was observed in aquifer sediments. This illustrates, that dichlobenil transported to aquifers does not contribute to the BAM-contamination in aquifers. A small, but significant degradation of BAM was observed in the upper part of the unsaturated zones in sandy sediments, but no degradation was observed in the clayey till sediment or in the deeper unsaturated zones. The insignificant degradation of BAM in aquifer systems shows that BAM pollution detected in aquifers will appear for a long time; and consequently the potential for natural attenuation of BAM in aquifer systems is limited.

  19. Geochemical and physical properties of soils and shallow sediments at the Savannah River Site

    SciTech Connect

    Looney, B.B.; Eddy, C.A.; Ramdeen, M.; Pickett, J. ); Rogers, V. . Savannah River Site Savannah River Lab., Aiken, SC ); Scott, M.T.; Shirley, P.A. )

    1990-08-31

    A program to characterize the geochemical and physical properties of the unimpacted soils and shallow sediments at the Savannah River Site (SRS) has been completed. The maximum, minimum, median, standard deviation, and mean values for metals, radionuclides, inorganic anions, organic compounds, and agricultural indicator parameters are summarized for six soil series that were identified as representative of the 29 soil series at SRS. The soils from unimpacted areas of SRS are typical of soils found in moderately aggressive weathering environments, including the southeastern United States. Appendix 8 organic compounds were detected in all samples. Since these constituents are not generally present in soil, this portion of the investigation was intended to assess possible laboratory artifacts. An additional objective of the SRS Soil Study was to determine if the composition of the split spoon sampler biased chemical analysis of the soils. Twenty-five duplicate samples were analyzed for a number of metals, radiological and agricultural parameters, and organics by two laboratories currently contracted with to analyze samples during waste site characterization. In all cases, the absolute values of the average differences are relatively small compared to the overall variability in the population. 31 refs., 14 figs., 48 tabs.

  20. Cadmium and associated metals in soils and sediments of wetlands across the Northern Plains, USA.

    PubMed

    Jacob, Donna L; Yellick, Alex H; Kissoon, La Toya T; Asgary, Aida; Wijeyaratne, Dimuthu N; Saini-Eidukat, Bernhardt; Otte, Marinus L

    2013-07-01

    Cadmium, present locally in naturally high concentrations in the Northern Plains of the United States, is of concern because of its toxicity, carcinogenic properties, and potential for trophic transfer. Reports of natural concentrations in soils are dominated by dryland soils with agricultural land uses, but much less is known about cadmium in wetlands. Four wetland categories - prairie potholes, shallow lakes, riparian wetlands, and river sediments - were sampled comprising more than 300 wetlands across four states, the majority in North Dakota. Cd, Zn, P, and other elements were analyzed by ICP-MS, in addition to pH and organic matter (as loss-on-ignition). The overall cadmium content was similar to the general concentrations in the area's soils, but distinct patterns occurred within categories. Cd in wetland soils is associated with underlying geology and hydrology, but also strongly with concentrations of P and Zn, suggesting a link with agricultural land use surrounding the wetlands. PMID:23583941

  1. Zinc distribution and acid-base mobilisation in vineyard soils and sediments.

    PubMed

    Fernández-Calviño, David; Pateiro-Moure, Mirian; Nóvoa-Muñoz, Juan Carlos; Garrido-Rodríguez, Beatriz; Arias-Estévez, Manuel

    2012-01-01

    Nineteen vineyard stands located in steep-slope areas of three wine-growing regions in northwest Spain were selected for this study. In each stand, a representative soil sample (19) and one or two sediment samples (24) were collected. In these samples, the Zn distribution in the solid phase was assessed. Moreover, the effect of pH on the release of zinc was determined using a batch-type experiment. The mean zinc concentration (109 mg kg(-1)) of the samples was lower than the maximum concentrations allowed by the European Union. Moreover, most of the zinc that appeared in vineyard soils was residual zinc, suggesting a tendency for zinc in these soils to be irreversibly bound to soil components, reducing its potential environmental impact. In sediments, the mean total Zn concentration (126 mg kg(-1)) was higher than those in the original soils and in the mobile fractions, which could mean a higher risk of liberation. Zinc release was higher under acidic conditions, in which release depends mainly on labile fractions. Under basic conditions, the release of Zn was lower and depended on Zn bound to crystalline oxyhydroxides.

  2. Sediment Supply Differences Between Soil and Bedrock Dominated Landscapes, San Gabriel Mountains, CA

    NASA Astrophysics Data System (ADS)

    Heimsath, A. M.; Dibiase, R.; Whipple, K. X.; Walsh, J.

    2009-12-01

    The importance of quantifying sediment delivery to channels is clear across disciplines. Processes that produce regolith, transport sediment, and incise valleys are complex, however, and are influenced by tectonic, lithologic, climatic, and anthropogenic factors in poorly constrained ways. As a result of our incomplete understanding of these processes, the extensive information encoded in the topography of a landscape remains out of reach. There remain significant gaps in our understanding of this interface between humans, the atmosphere, biosphere, and lithosphere. One of the most significant gaps is quantifying the controls on soil presence or absence in hilly and mountainous regions and the impacts of these controls on sediment supply to channels. Here we evaluate the controls exerted by erosion on soil production rates in the San Gabriel Mountains, California, measured by in situ produced cosmogenic nuclide (10Be) analyses and two widely used topographic metrics: mean hillslope gradient and the channel steepness index. We present data that show that the transition from soil-mantled to rocky landscapes is set by the maximum rate of soil production. Seventy measurements of 10Be concentrations in detrital sands collected from catchments spanning our field area yield a strikingly clear relationship between mean basin slope and average erosion rate. These data quantify a clear increase of erosion rate with mean slope, from the relatively gentle catchments in the west (10 degrees avg. slope) to the steepest soil mantled catchments near the middle of the range (30 degrees avg. slope). Above about 30 degrees, slopes are at threshold despite a factor of five increase in erosion rates, but become bedrock-dominated. To test controls on the transition from soil to bedrock-dominated landscapes, we measured soil production rates from point samples of bedrock and saprolite in forty-seven soil pits from across different soil-mantled hillslopes spanning the study area. Although

  3. Seasonal herbicide monitoring in soil, runoff and sediments of an olive orchard under conventional tillage

    NASA Astrophysics Data System (ADS)

    Calderón, Maria Jesus; de Luna, Elena; Gómez, José Alfonso; Cornejo, Juan; Hermosín, M. Carmen

    2015-04-01

    Several pollution episodes in surface and groundwaters with pesticides have occurred in areas where olive crops are established. For that reason, it is necessary to know the evolution of some pesticides in olive trees plantation depending on their seasonal application. This is especially important when conventional tillage is used. A monitoring of two herbicides (terbuthylazine and oxyfluorfen)in the first cm of soil and, in runoff and sediment yield was carried out after several rainfall events. The rainfall occurred during the study was higher in winter than in spring giving rise more runoff in winter. However, no differences in sediment yields were observed between spring and winter. Terbuthylazine depletion from soil is associated to the first important rainfall events in both seasons (41 mm in spring and 30 mm in winter). At the end of the experiment, no terbuthylazine soil residues were recovered in winter whereas 15% of terbuthylazine applied remained in spring. Oxyfluorfen showed a character more persistent than terbuthylazine remaining 48% of the applied at the end of the experiment due to its low water solubility. Higher percentage from the applied of terbuthylazine was recovered in runoff in winter (0.55%) than in spring (0.17%). Nevertheless, no differences in terbuthylazine sediments yields between both seasons were observed. That is in agreement with the values of runoff and sediment yields accumulated in tanks in both seasons. Due to the low water solubility of oxyfluorfen very low amount of this herbicide was recovered in runoff. Whereas, in sediment yields the 39.5% of the total applied was recovered. These data show that the dissipation of terbuthylazine from soil is closely related with leaching processes and in less extent with runoff. However, oxyfluorfen dissipation is more affected by runoff processes since this herbicide is co-transported in sediment yields. Keywords: olive crop, pesticide, runoff, sediments, surface water, groundwater

  4. Distribution of trace elements in sediment and soil from river Vardar Basin, Macedonia/Greece.

    PubMed

    Popov, Stanko Ilić; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu

    2016-01-01

    A systematic study was carried out to investigate the distribution of 59 elements in the sediment and soil samples collected from the river Vardar (Republic of Macedonia and Greece) and its major tributaries. The samples were collected from 28 sampling sites. Analyses were performed by inductively coupled plasma-mass spectrometry. R-mode factor analysis (FA) was used to identify and characterise element associations. Seven associations of elements were determined by the method of multivariate statistics. Every factor (Factors 1-3 and 6 and 7 as geogenic and Factors 4 and 5 as anthropogenic associations of elements) are examined and explained separately. The distribution of various elements showed that there is a presence of anthropogenic elements (Ag, Cd, Cu, Ge, Pb, Sn and Zn) introduced in the river sediments and soils from the mining, metallurgical, industrial and agricultural activities in Vardar River Basin, which covers most of the Republic of Macedonia and Central-northern part of Greece. PMID:26422060

  5. Soil conservation and the reduction of erosion and sedimentation in the Coon Creek basin, Wisconsin

    USGS Publications Warehouse

    Trimble, S.W.; Lund, S.W.

    1982-01-01

    The Coon Creek basin, in the Driftless Area of Wisconsin, has been strikingly transformed by soil conservation measures since the 1930's. Comparison of sheet and rill erosion by use of the Universal Soil Loss Equation, shows 1975 erosion rates on upland fields to be about one-fourth those of 1934. Average annual sedimentation accumulation in small reservoirs declined from about 5,000 megagrams per square kilometer in 1936-45 to about 50 megagrams per square kilometer in 1962-75. Analysis of deposition in tributary valleys suggests that annual rates declined from about 3,700 megagrams per square kilometer in the 1930 's to about 35-70 megagrams per square kilometer in recent years. These reductions in erosion and sedimentation are due principally to improvements in land management and, to a lesser degree, to changes in land use. (USGS)

  6. Distribution of trace elements in sediment and soil from river Vardar Basin, Macedonia/Greece.

    PubMed

    Popov, Stanko Ilić; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu

    2016-01-01

    A systematic study was carried out to investigate the distribution of 59 elements in the sediment and soil samples collected from the river Vardar (Republic of Macedonia and Greece) and its major tributaries. The samples were collected from 28 sampling sites. Analyses were performed by inductively coupled plasma-mass spectrometry. R-mode factor analysis (FA) was used to identify and characterise element associations. Seven associations of elements were determined by the method of multivariate statistics. Every factor (Factors 1-3 and 6 and 7 as geogenic and Factors 4 and 5 as anthropogenic associations of elements) are examined and explained separately. The distribution of various elements showed that there is a presence of anthropogenic elements (Ag, Cd, Cu, Ge, Pb, Sn and Zn) introduced in the river sediments and soils from the mining, metallurgical, industrial and agricultural activities in Vardar River Basin, which covers most of the Republic of Macedonia and Central-northern part of Greece.

  7. Dichlorodiphenyltrichloroethane in soil, river sediment, and fish in the Amazon in Brazil.

    PubMed

    Torres, Joao P M; Pfeiffer, Wolfgang C; Markowitz, Steve; Pause, Ronald; Malm, Olaf; Japenga, Jan

    2002-02-01

    Dichlorodiphenyltrichloroethane (DDT), its main metabolites, and other organochlorines were analyzed in soils (n=6), fluvial sediments (n=14), and fish (n=10) that were collected in several areas of the Amazon region in Brazil. The samples were analyzed by capillary column gas chromatography coupled to electron capture detection. DDT residues were present in most of the collected sediments in concentrations of approximately 10 to 100 micro/kg (ppb, dry weight). Some urban top soils were found to have more than 1 mg/kg (ppm). In fish, as much as 0.5 mg/kg of total DDT (wet weight) was found in the edible parts. The presence of p,p'-DDT in most of the samples reflects the use of this insecticide against vectors of malaria between 1946 and 1993, which has led to its ubiquitous presence in the environment of the Brazilian Amazon.

  8. AN IMPROVED AIR-DRIVEN TYPE OF ULTRACENTRIFUGE FOR MOLECULAR SEDIMENTATION

    PubMed Central

    Bauer, Johannes H.; Pickels, Edward G.

    1937-01-01

    1. A description is given of the construction details and operation characteristics of an improved type of air-driven ultracentrifuge operating in vacuum and suitable for the determination of sedimentation constants of protein molecules. 2. The rotor of the centrifuge is made of a forged aluminum alloy; it is oval in shape, measures 185 mm. at its greatest diameter, and weighs 3,430 gm. It carries a transparent cell located at a distance of 65 mm. from the axis of rotation and designed to accommodate a fluid column 15 mm. high. 3. The rotor has been run repeatedly over long periods at a speed of 60,000 R.P.M., which corresponds to a centrifugal force of 260,000 times gravity in the center of the cell. At this speed no deformation of the rotor nor leakage of the cell has been observed. 4. The sharp definition of sedimentation photographs taken at high speed serves to indicate the absence of detectable vibrations in the centrifuge. 5. When a vacuum of less than 1 micron of mercury is maintained in the centrifuge chamber, the rise in the rotor temperature amounts to only 1 or 2°C. after several hours' run at high speed. 6. There has been no evidence of convection currents interfering with normal sedimentation of protein molecules in the centrifugal field. 7. A driving air pressure of about 18 pounds per square inch is sufficient to maintain the centrifuge at a steady speed of 60,000 R.P.M. With a driving pressure of 80 pounds per square inch, it can be accelerated to this speed in less than 20 minutes, and also brought to rest in about the same length of time by the application of the braking system. 8. The adaptation of Svedberg's optical systems to this centrifuge for photographically recording the movement of sedimentation boundaries is described. PMID:19870619

  9. AN IMPROVED AIR-DRIVEN TYPE OF ULTRACENTRIFUGE FOR MOLECULAR SEDIMENTATION.

    PubMed

    Bauer, J H; Pickels, E G

    1937-03-31

    1. A description is given of the construction details and operation characteristics of an improved type of air-driven ultracentrifuge operating in vacuum and suitable for the determination of sedimentation constants of protein molecules. 2. The rotor of the centrifuge is made of a forged aluminum alloy; it is oval in shape, measures 185 mm. at its greatest diameter, and weighs 3,430 gm. It carries a transparent cell located at a distance of 65 mm. from the axis of rotation and designed to accommodate a fluid column 15 mm. high. 3. The rotor has been run repeatedly over long periods at a speed of 60,000 R.P.M., which corresponds to a centrifugal force of 260,000 times gravity in the center of the cell. At this speed no deformation of the rotor nor leakage of the cell has been observed. 4. The sharp definition of sedimentation photographs taken at high speed serves to indicate the absence of detectable vibrations in the centrifuge. 5. When a vacuum of less than 1 micron of mercury is maintained in the centrifuge chamber, the rise in the rotor temperature amounts to only 1 or 2 degrees C. after several hours' run at high speed. 6. There has been no evidence of convection currents interfering with normal sedimentation of protein molecules in the centrifugal field. 7. A driving air pressure of about 18 pounds per square inch is sufficient to maintain the centrifuge at a steady speed of 60,000 R.P.M. With a driving pressure of 80 pounds per square inch, it can be accelerated to this speed in less than 20 minutes, and also brought to rest in about the same length of time by the application of the braking system. 8. The adaptation of Svedberg's optical systems to this centrifuge for photographically recording the movement of sedimentation boundaries is described.

  10. AN IMPROVED AIR-DRIVEN TYPE OF ULTRACENTRIFUGE FOR MOLECULAR SEDIMENTATION.

    PubMed

    Bauer, J H; Pickels, E G

    1937-03-31

    1. A description is given of the construction details and operation characteristics of an improved type of air-driven ultracentrifuge operating in vacuum and suitable for the determination of sedimentation constants of protein molecules. 2. The rotor of the centrifuge is made of a forged aluminum alloy; it is oval in shape, measures 185 mm. at its greatest diameter, and weighs 3,430 gm. It carries a transparent cell located at a distance of 65 mm. from the axis of rotation and designed to accommodate a fluid column 15 mm. high. 3. The rotor has been run repeatedly over long periods at a speed of 60,000 R.P.M., which corresponds to a centrifugal force of 260,000 times gravity in the center of the cell. At this speed no deformation of the rotor nor leakage of the cell has been observed. 4. The sharp definition of sedimentation photographs taken at high speed serves to indicate the absence of detectable vibrations in the centrifuge. 5. When a vacuum of less than 1 micron of mercury is maintained in the centrifuge chamber, the rise in the rotor temperature amounts to only 1 or 2 degrees C. after several hours' run at high speed. 6. There has been no evidence of convection currents interfering with normal sedimentation of protein molecules in the centrifugal field. 7. A driving air pressure of about 18 pounds per square inch is sufficient to maintain the centrifuge at a steady speed of 60,000 R.P.M. With a driving pressure of 80 pounds per square inch, it can be accelerated to this speed in less than 20 minutes, and also brought to rest in about the same length of time by the application of the braking system. 8. The adaptation of Svedberg's optical systems to this centrifuge for photographically recording the movement of sedimentation boundaries is described. PMID:19870619

  11. AIR EMISSIONS FROM THE TREATMENT OF SOILS CONTAMINATED WITH PETROLEUM FUELS AND OTHER SUBSTANCES

    EPA Science Inventory

    The report updates a 1992 report that summarizes available information on air emissions from the treatment of soils contaminated with fuels. Soils contaminated by leaks or spills of fuel products, such as gasoline or jet fuel, are a nationwide concern. Air emissions during remedi...

  12. Sediment and Soil Profiles of Taylor and Wright Valleys, Antarctica, as Analogs for Mars

    NASA Astrophysics Data System (ADS)

    Englert, P. A.; Bishop, J. L.; Patel, S.; Koeberl, C.; Gibson, E. K.

    2013-12-01

    The Antarctic Dry Valleys are extremely cold and dry desert environments. They represent a unique analog for Martian surface development conditions. Chemistry and mineralogy of soils and sediments from Taylor and Wright Valleys were analyzed [1-4]. Samples from selected lakes, ponds and nearby surface areas were collected in 1979/1980, from sediments below Lake Hoare in 1994/95, and from lake surfaces in 2005/06. Surface samples are from Lakes Brownworth, Vanda and Fryxell; sediment cores from Lake Hoare, Don Juan and Don Quixote ponds. Systematic analysis by INAA, XRD, VNIR and mid-infrared spectroscopy, and other methods is underway for all samples. Classical major element weathering / pedogenesis ratiosand major element weathering indices are applied to ADV as well as MER and MSL rocks and soils. The Chemical Index of Alteration (CIA) values were used to characterize weathering conditions in Antarctic soils of Barton Peninsula [5] and for sediment layers in Antarctic drill cores [6]. The CIAs of sediment layers in drill cores are largely explained by the CIAs of source materials and reflect little or isochemical weathering. At Barton Peninsula with a less arid environment than the ADVs, CIAs of soils generally exceed those of source rocks. In Figure 1, two of several ADV soil source rocks and three sets of ADV soil and sediment CIAs are compared to molar Al2O3/TiO2 ratios. ADV CIA data are clustered and, as expected, lower than those of Barton Penisula, indicating a lesser degree of weathering. Very low ADV soil CIAs indicate sulfur rich samples. Full geochemical analysis as proposed will provide good indicators of weathering where historical to contemporary alteration conditions are liquid water based. Investigating elemental relationships for analogs that can be applied to Mars elemental abundance data bases is therefore important to assist in evaluating the extent of water based alteration derived from indicators in the Martian surface. References: [1] Gibson

  13. Development and application of screening tools for biodegradation in water-sediment systems and soil.

    PubMed

    Junker, Thomas; Coors, Anja; Schüürmann, Gerrit

    2016-02-15

    Two new screening-test systems for biodegradation in water-sediment systems (WSST; Water-Sediment Screening Tool) and soil (SST; Soil Screening Tool) were developed in analogy with the water-only test system OECD 301C (MITI-test). The test systems could be applied successfully to determine reproducible experimental mineralization rates and kinetics on the screening-test level for fifteen organic chemicals in water (MITI), water-sediment (WSST) and soil (SST). Substance-specific differences were observed for mineralization compared among the three test systems. Based on mineralization rate and mineralization half-life, the fifteen compounds could be grouped into four biodegradation categories: substances with high mineralization and a half-life <28 days in (1) all three test systems, (2) only in the MITI test and in the WSST, (3) only in the SST, and (4) none of the test systems. The observed differences between the MITI results and the WSST and SST biodegradation rates of the compounds do not reflect their (reversible) sorption into organic matter in terms of experimental K(oc) values and log D values for the relevant pH range. Regarding mineralization kinetics we recommend to determine the lag-phase, mineralization half-life and mineralization rate using a 5-parameter logistic regression for degradation curves with and without lag-phase. Experimental data obtained with the WSST and the SST could be verified by showing good agreement with biodegradation data from databases and literature for the majority of compounds tested. Thus, these new screening-tools for water-sediment and soil are considered suitable to determine sound and reliable quantitative mineralization data including mineralization kinetics in addition to the water-only ready biodegradability tests according to OECD 301.

  14. Instrumental neutron activation analysis of soil and sediment samples from Siwa Oasis, Egypt

    NASA Astrophysics Data System (ADS)

    Badawy, Wael M.; Ali, Khaled; El-Samman, Hussein M.; Frontasyeva, Marina V.; Gundorina, Svetlana F.; Duliu, Octavian G.

    2015-07-01

    Instrumental neutron activation analysis was used to study geochemical peculiarities of the Siwa Oasis in the Western Egyptian Desert. A total of 34 elements were determined in soil and sediment samples (Na, Mg, Al, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Sb, I, Cs, Ba, La, Ce, Nd, Eu, Tb, Dy, Tm, Yb, Hf, Ta, Th, and U). For data interpretation Cluster analysis was applied. Comparison with the available literature data was carried out.

  15. Development and application of screening tools for biodegradation in water-sediment systems and soil.

    PubMed

    Junker, Thomas; Coors, Anja; Schüürmann, Gerrit

    2016-02-15

    Two new screening-test systems for biodegradation in water-sediment systems (WSST; Water-Sediment Screening Tool) and soil (SST; Soil Screening Tool) were developed in analogy with the water-only test system OECD 301C (MITI-test). The test systems could be applied successfully to determine reproducible experimental mineralization rates and kinetics on the screening-test level for fifteen organic chemicals in water (MITI), water-sediment (WSST) and soil (SST). Substance-specific differences were observed for mineralization compared among the three test systems. Based on mineralization rate and mineralization half-life, the fifteen compounds could be grouped into four biodegradation categories: substances with high mineralization and a half-life <28 days in (1) all three test systems, (2) only in the MITI test and in the WSST, (3) only in the SST, and (4) none of the test systems. The observed differences between the MITI results and the WSST and SST biodegradation rates of the compounds do not reflect their (reversible) sorption into organic matter in terms of experimental K(oc) values and log D values for the relevant pH range. Regarding mineralization kinetics we recommend to determine the lag-phase, mineralization half-life and mineralization rate using a 5-parameter logistic regression for degradation curves with and without lag-phase. Experimental data obtained with the WSST and the SST could be verified by showing good agreement with biodegradation data from databases and literature for the majority of compounds tested. Thus, these new screening-tools for water-sediment and soil are considered suitable to determine sound and reliable quantitative mineralization data including mineralization kinetics in addition to the water-only ready biodegradability tests according to OECD 301. PMID:26774960

  16. Modelling the initial structure dynamics of soil and sediment exemplified for a constructed hydrological catchment

    NASA Astrophysics Data System (ADS)

    Maurer, Thomas; Schneider, Anna; Gerke, Horst H.

    2016-04-01

    The structure of a hydrological catchment is determined by the geometry of the boundaries and the spatial distribution of soil and sediment properties. Models of the 3D subsurface structure and the soil heterogeneity have often been built based on geostatistical approaches and conditional simulations for spatial interpolation between measurements. Here, an alternative model was proposed that generated 3D subsurface structures by imitating basic structures resulting from mass distribution processes. Instead of directly assuming stochastic variations of the subsurface structure, the present approach assumed stochastic variations in parameters of the process-based algorithms of the generator models. The constructed hydrological catchment "Hühnerwasser" located in the Lower Lusatia region of Brandenburg, Germany, was used as an example for the development of such a 3D structure generator model. Boundary geometries and changes in the surface topography due to erosion and sedimentation processes were quantified on the basis of digital elevation models (DEMs) derived from aerial photographs and terrestrial laser scanning information. Basic sediment properties came i) from a geological model of the parent material at the outcrop site, ii) from actual soil sample measurements on-site, and iii) based on stochastic texture variations. Sediment distributions were generated according to construction processes such as sediment dumping, particle segregation, and soil compaction. The resulting internal structures reflect the formation of spoil cones and surface compaction by machinery. The simulated 3D model scenarios of soil texture and bulk density distributions were incorporated in a gridded 3D volume model using the 3D software tool GoCAD (Paradigm Ltd.). This 3D distributed solid phase structure of the catchment allowed for a more direct comparison with observations using minimal invasive methods. By including structural changes over time (e.g., derived from DEM

  17. Organic compound composition in soil and sediments collected in Jackson, Mississippi.

    PubMed

    Gołębiowski, Marek; Stepnowski, Piotr; Hemmingway, Tometrick; Leszczyńska, Danuta

    2016-01-01

    The aim of our study was to identify organic pollutants found in soil and sediment samples collected within the Jackson, MS metropolitan area. The chemical characterization of the organic compound fractions in soil and sediment samples was carried out by separating the organic fraction using column chromatography (CC) and quantitatively analyzing the polycyclic aromatic hydrocarbons (PAHs), n-alkanes and other organic compounds using gas chromatography-electron impact mass spectrometry (GC-MS). Fifty-six compounds were identified and quantified in the soil samples and 33 compounds were identified and quantified in the sediment samples. The PAHs, n-alkanes and other organic compound profiles in the soil and sediment samples were compared. The percentage contents of the organic compounds in the soil samples were very diverse (from traces to 12.44 ± 1.47%). The compounds present in the highest concentrations were n-alkanes: n-C31 (12.44 ± 1.47%), n-C29 (11.64 ± 1.21%), and n-C33 (8.95 ± 1.08%). The components occurring in smaller quantities (from 1% to 5%) were 2 PAHs (fluoranthene 1.28 ± 0.25%, pyrene 1.16 ± 0.20%), 10 n-alkanes from n-C21 (1.25 ± 0.29%) to n-C32 (2.67 ± 0.52%) and 11 other compounds (e.g., 2-pentanol, 4-methyl (3.33 ± 0.44%), benzyl butyl phthalate (4.25 ± 0.59%), benzenedicarboxylic acid (1.14 ± 0.08%), ethane, 1,1-diethoxy (3.15 ± 0.41) and hexadecanoic acid (2.52 ± 0.34). The soil samples also contained 30 compounds present in concentrations <1% (e.g., anthracene (0.13 ± 0.04%), n-C20 (0.84 ± 0.21%) and acetic acid (0.12 ± 0.04%). The compounds present in the highest concentrations in the sediment samples were PAHs: pyrene (7.73 ± 1.15%) and fluoranthene (6.23 ± 1.07%) and n-alkanes: n-C31 (6.74 ± 1.21%), n-C29 (6.65 ± 0.98%) and n-C27 (6.13 ± 1.09%). The remaining organic compounds were present in smaller quantities (< 5%).

  18. Determination of polychlorinated biphenyls in soil and sediment by selective pressurized liquid extraction with immunochemical detection.

    PubMed

    Van Emon, Jeanette M; Chuang, Jane C; Bronshtein, Alisa; Altstein, Miriam

    2013-10-01

    A selective pressurized liquid extraction (SPLE) method was developed for a streamlined sample preparation/cleanup to determine Aroclors and coplanar polychlorinated biphenyls (PCBs) in soil and sediment. The SPLE was coupled with an enzyme-linked immunosorbent assay (ELISA) for an effective analytical approach for environmental monitoring. Sediment or soil samples were extracted with alumina, 10% AgNO3 in silica, and sulfuric acid impregnated silica with dichloromethane at 100°C and 2000 psi. The SPLE offered simultaneous extraction and cleanup of the PCBs and Aroclors, eliminating the need for a post-extraction cleanup prior to ELISA. Two different ELISA methods: (1) an Aroclor ELISA and (2) a coplanar PCB ELISA were evaluated. The Aroclor ELISA utilized a polyclonal antibody (Ab) with Aroclor 1254 as the calibrant and the coplanar PCB ELISA kit used a rabbit coplanar PCB Ab with PCB-126 as the calibrant. Recoveries of Aroclor 1254 in two reference soil samples were 92±2% and 106±5% by off-line coupling of SPLE with ELISA. The average recovery of Aroclor 1254 in spiked soil and sediment samples was 92±17%. Quantitative recoveries of coplanar PCBs (107-117%) in spiked samples were obtained with the combined SPLE-ELISA. The estimated method detection limit was 10 ng g(-1) for Aroclor 1254 and 125 pg g(-1) for PCB-126. Estimated sample throughput for the SPLE-ELISA was about twice that of the stepwise extraction/cleanup needed for gas chromatography (GC) or GC/mass spectrometry (MS) detection. ELISA-derived uncorrected and corrected Aroclor 1254 levels correlated well (r=0.9973 and 0.9996) with the total Aroclor concentrations as measured by GC for samples from five different contaminated sites. ELISA-derived PCB-126 concentrations were higher than the sums of the 12 coplanar PCBs generated by GC/MS with a positive correlation (r=0.9441). Results indicate that the SPLE-ELISA approach can be used for quantitative or qualitative analysis of PCBs in soil and

  19. Consumption of freons CFC-11 and CFC-12 by anaerobic sediments and soils

    USGS Publications Warehouse

    Lovley, D.R.; Woodward, J.C.

    1992-01-01

    A variety of anaerobic sediments and soils consumed CFC-11 (CFCl3) and CFC-12 (CF2Cl2). An aerobic soil did not. Active microbial metabolism was required for CFC-12 uptake in all of the sediments examined. CFC-11 uptake was faster in the presence of microbial activity, but reduced components in the sediments also resulted in nonenzymatic CFC-11 consumption in most instances. CFC-12 uptake in a culture of Clostridium pasteurianum provided a model for the sediment uptake of CFC-11 and CFC-12 that required active microbial metabolism. Consumption of CFC-11 in the presence of reduced hematin demonstrated a potential mechanism for nonenzymatic CFC-11 consumption. These findings demonstrate that CFC-11 and CFC-12 are not biochemically inert under anaerobic conditions. This suggests that anaerobic degradation of CFC-11 and CFC-12 in anaerobic landfills might prevent some disposed CFC-11 and CFC-12 from entering the atmosphere. The results also suggest that CFC-11 and CFC-12 cannot be used as stable tracers in anaerobic environments. Furthermore, although the microbial sink for atmospheric CFC-11 and CFC-12 is much less than current anthropogenic release, this sink could have a significant long-term effect on the amount of CFC-11 and CFC-12 reaching the stratosphere.

  20. Diversity and Composition of Bacterial Community in Soils and Lake Sediments from an Arctic Lake Area.

    PubMed

    Wang, Neng Fei; Zhang, Tao; Yang, Xiao; Wang, Shuang; Yu, Yong; Dong, Long Long; Guo, Yu Dong; Ma, Yong Xing; Zang, Jia Ye

    2016-01-01

    This study assessed the diversity and composition of bacterial communities within soils and lake sediments from an Arctic lake area (London Island, Svalbard). A total of 2,987 operational taxonomic units were identified by high-throughput sequencing, targeting bacterial 16S rRNA gene. The samples from four sites (three samples in each site) were significantly different in geochemical properties and bacterial community composition. Proteobacteria and Acidobacteria were abundant phyla in the nine soil samples, whereas Proteobacteria and Bacteroidetes were abundant phyla in the three sediment samples. Furthermore, Actinobacteria, Chlorobi, Chloroflexi, Elusimicrobia, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria significantly varied in their abundance among the four sampling sites. Additionally, members of the dominant genera, such as Clostridium, Luteolibacter, Methylibium, Rhodococcus, and Rhodoplanes, were significantly different in their abundance among the four sampling sites. Besides, distance-based redundancy analysis revealed that pH (p < 0.001), water content (p < 0.01), ammonium nitrogen ([Formula: see text]-N, p < 0.01), silicate silicon ([Formula: see text]-Si, p < 0.01), nitrite nitrogen ([Formula: see text]-N, p < 0.05), organic carbon (p < 0.05), and organic nitrogen (p < 0.05) were the most significant factors that correlated with the bacterial community composition. The results suggest soils and sediments from a lake area in the Arctic harbor a high diversity of bacterial communities, which are influenced by many geochemical factors of Arctic environments. PMID:27516761

  1. Control of soil acidification by fluvial sedimentation in an estuarine floodplain, eastern Australia

    NASA Astrophysics Data System (ADS)

    Lin, C.; Melville, M. D.

    1993-05-01

    A shallow stratigraphic sequence with associated pyrite-induced soil acidification was investigated along a transect from the levee to the backswamp in an estuarine floodplain of eastern Australia. Three sedimentary layers were identified and interpreted to correspond with three depositional stages. Firstly, a layer of humic, pyrite-rich, silty mud was deposited under a saline, mangrove-inhabited, intertidal environment during the present high sea level episode. This pyritic layer is buried by the second sedimentary layer of grey brown mud with limited pyrite content, that was deposited in a brackish lagoonal environment. This material now represents much of the contemporary backswamp surface. The third sedimentary layer is a sandy mud without pyrite, that has been deposited by freshwater overbank floods. It is concluded that fluvial sedimentation has been increasingly important in the development of the stratigraphic sequence, controlling the pyrite content, thickness and occurrence depth of the pyritic layer. The present drainage conditions have allowed oxidation of pyrite in the soils of the backswamp and the resulting acidification has caused elevated concentrations of toxic aluminium that threaten the local environment. However, in the levee, the pyritic layer is covered by thick non-pyritic freshwater sediments and low-pyritic lagoonal sediments, and the soil profiles are unlikely to contribute to any acidification hazard.

  2. Diversity and Composition of Bacterial Community in Soils and Lake Sediments from an Arctic Lake Area

    PubMed Central

    Wang, Neng Fei; Zhang, Tao; Yang, Xiao; Wang, Shuang; Yu, Yong; Dong, Long Long; Guo, Yu Dong; Ma, Yong Xing; Zang, Jia Ye

    2016-01-01

    This study assessed the diversity and composition of bacterial communities within soils and lake sediments from an Arctic lake area (London Island, Svalbard). A total of 2,987 operational taxonomic units were identified by high-throughput sequencing, targeting bacterial 16S rRNA gene. The samples from four sites (three samples in each site) were significantly different in geochemical properties and bacterial community composition. Proteobacteria and Acidobacteria were abundant phyla in the nine soil samples, whereas Proteobacteria and Bacteroidetes were abundant phyla in the three sediment samples. Furthermore, Actinobacteria, Chlorobi, Chloroflexi, Elusimicrobia, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria significantly varied in their abundance among the four sampling sites. Additionally, members of the dominant genera, such as Clostridium, Luteolibacter, Methylibium, Rhodococcus, and Rhodoplanes, were significantly different in their abundance among the four sampling sites. Besides, distance-based redundancy analysis revealed that pH (p < 0.001), water content (p < 0.01), ammonium nitrogen (NH4+-N, p < 0.01), silicate silicon (SiO42--Si, p < 0.01), nitrite nitrogen (NO2--N, p < 0.05), organic carbon (p < 0.05), and organic nitrogen (p < 0.05) were the most significant factors that correlated with the bacterial community composition. The results suggest soils and sediments from a lake area in the Arctic harbor a high diversity of bacterial communities, which are influenced by many geochemical factors of Arctic environments. PMID:27516761

  3. Partial least-squares regression for linking land-cover patterns to soil erosion and sediment yield in watersheds

    NASA Astrophysics Data System (ADS)

    Shi, Z. H.; Ai, L.; Li, X.; Huang, X. D.; Wu, G. L.; Liao, W.

    2013-08-01

    There are strong ties between land cover patterns and soil erosion and sediment yield in watersheds. The spatial configuration of land cover has recently become an important aspect of the study of geomorphological processes related to erosion within watersheds. Many studies have used multivariate regression techniques to explore the response of soil erosion and sediment yield to land cover patterns in watersheds. However, many landscape metrics are highly correlated and may result in redundancy, which violates the assumptions of a traditional least-squares approach, thus leading to singular solutions or otherwise biased parameter estimates and confidence intervals. Here, we investigated the landscape patterns within watersheds in the Upper Du River watershed (8973 km2) in China and examined how the spatial patterns of land cover are related to the soil erosion and sediment yield of watersheds using hydrological modeling and partial least-squares regression (PLSR). The results indicate that the watershed soil erosion and sediment yield are closely associated with the land cover patterns. At the landscape level, landscape characteristics, such as Shannon’s diversity index (SHDI), aggregation index (AI), largest patch index (LPI), contagion (CONTAG), and patch cohesion index (COHESION), were identified as the primary metrics controlling the watershed soil erosion and sediment yield. The landscape characteristics in watersheds could account for as much as 65% and 74% of the variation in soil erosion and sediment yield, respectively. Greater interspersion and an increased number of patch land cover types may significantly accelerate soil erosion and increase sediment export. PLSR can be used to simply determine the relationships between land-cover patterns and watershed soil erosion and sediment yield, providing quantitative information to allow decision makers to make better choices regarding landscape planning. With readily available remote sensing data and rapid

  4. Silica colloid formation enhances performance of sediment microbial fuel cells in a low conductivity soil.

    PubMed

    Domínguez-Garay, Ainara; Berná, Antonio; Ortiz-Bernad, Irene; Esteve-Núñez, Abraham

    2013-02-19

    The performance of sediment microbial fuel cells (SMFCs) is usually limited by the structure, moisture, and salt content of the soil where they are allocated. Despite the influence of soil, so far most of efforts to improve SMFCs have been limited to the hardware design of the bioelectrochemical device. Our main objective was to enhance performance of SMFCs by stimulating the in situ formation of silica colloids in a low conductivity rice paddy soil. Our results have revealed that the presence of a silica colloid network, described by cryo-SEM analysis, reduced soil resistivity, enhanced ion mobility and consequently enhanced the power production by a factor of 10. Furthermore, our silica-supplemented soil showed better utilization of the electron donor, either acetate or natural rice root exudates, by electrogenic microbial populations. Sustainable manipulation of soil micromorphology using environmentally friendly reagents such as silica offers a novel approach for enhancing the performance of in situ microbial electrochemical applications in low conductivity soils, thus silica colloid geoengineering should be considered as part of future applications of SMFCs.

  5. Cleaning contaminated soil using electrical heating and air stripping

    SciTech Connect

    Buettner, H.M.; Daily, W.D.

    1995-08-01

    In the summer of 1992, a proof-of-concept demonstration of direct electrical heating and air stripping was conducted for enhancing the removal of a volatile organic contaminant, trichloroethylene (TCSE), from soil. Six electrodes were buried in shallow boreholes so that a target region 6.1 m in diameter and 3.05 m in height was heated by ohmic dissipation of power-line-frequency electrical currents supplied by a diesel generator. Air stripping of TCE contamination from the same region was accomplished from a single well at the center of the heated volume. The electrical energy used during the demonstration was 3.46 {times} 10{sup 10} J (9,600 kW {center_dot} h), and the temperature of the extracted air rose from 16 C to 38 C. An energy balance shows that input energy is consistent with the temperature rise in the target volume and the amount of water vaporized at the electrodes. Prior to heating, the TCE concentration in the vapor decreased from about 80 parts per million by volume (ppm{sub v}) to around 60 ppm{sub v}. As soon as electrical heating started, TCE concentrations began to increase. Some concentration data were lost shortly after electrical heating began. After the system was repaired, the TCE concentration fell rapidly from about 140 ppm{sub v} to 5 ppm{sub v} over a period of about 25 days. A simple two-dimensional model for calculation of heating rates is also presented and verified experimentally. Finally some of the operation and safety issues associated with electrical heating are discussed.

  6. Mineralogy and arsenic mobility in arsenic-rich Brazilian soils and sediments

    USGS Publications Warehouse

    de Mello, J.W.V.; Roy, W.R.; Talbott, J.L.; Stucki, J.W.

    2006-01-01

    Background. Soils and sediments in certain mining regions of Brazil contain an unusually large amount of arsenic (As), which raises concerns that mining could promote increased As mobility, and thereby increase the risks of contaminating water supplies. Objectives. The purpose of t his study was to identify the most important factors governing As mobility in sediments and soils near three gold-mining sites in the State of Minas Gerais, Brazil. Methods. Surface and sub-surface soil samples were collected at those sites and characterized by chemical and mineralogical analyses. Oxalate (Feo) and citrate-bicarbonate-dithionite (Fed) iron contents were determined by atomic absorption spectroscopy (AAS). Arsenic mobilization was measured after incubating the samples in a 2.5 mM CaCl2 solution under anaerobic conditions for 1, 28, 56, 84, or 112 days. The solution concentrations of As, Fe, and Mn were then measured by inductively coupled plasma-mass spectrometry (ICP-MS) and AAS, respectively. Results and Discussion. Results indicated that As mobilization is largely independent of both the total As and the Feo/Fed ratio of the solid phase. Soluble As is roughly controlled by the Fe (hydr)oxide content of the soil, but a closer examination of the data revealed the importance of other highly weathered clay minerals and organic matter. Large amounts of organic matter and a low iron oxide content should favor As leaching from soils and sediments. Under reducing conditions, As is mobilized by the reductive dissolution of Fe and/or Mn oxides. However, released As may be readsorbed depending on the sorptive properties of the soil. Gibbsite is particularly effective in adsorbing or readsorbing As, as is the remaining unreduced fraction of the iron (hydr)oxides. Conclusion and Outlook. In general, low soluble As is rel ated to the presence of gibbsite, a large amount of iron oxides, and a lack of organic matter in the solid phase. This has environmental significance because

  7. Alterations to Soil and Eroded Sediment Carbon after the Rim Fire, Yosemite National Park

    NASA Astrophysics Data System (ADS)

    Lever, R.; Berhe, A. A.; Fogel, M. L.; Hockaday, W. C.; Kuhn, T. J.; Austin, L. J.

    2015-12-01

    The soil system is a critical global carbon (C) pool that is under threat from both fire and erosion perturbations. In the Western United States, forecasted increases in average temperatures, as well as for extended summer growing seasons, indicate that large fuel loads and ideal fire conditions may generate more high intensity wildfires. Understanding how wildfires control soil C storage is critical for both projecting losses of soil C and how to better manage fire regimes to increase soil C storage. This research addresses a topic that has only been briefly addressed by the current body of literature - the erosion of pyrogenic C, or C which has undergone some combustion, which has the potential to affect storage of C within the soil system. The Rim Fire was a wildfire that consumed over 250,000 acres of land in Yosemite National Park and Stanislaus National Forest in 2013. After the fire, sediment traps were established on a hillslope under three treatment conditions: 1) high burn severity — high slope; 2) high burn severity — moderate slope, and; 3) moderate burn severity — high slope. Sediments were collected from these traps after every major precipitation event following the Rim Fire, Additionally, representative soils were collected from the source areas of the eroded material. Differences in chemical composition of organic matter and concentration of pyrogenic matter were determined using 13C Cross-Polarization Magic Angle Spinning (CPMAS) Nuclear Magnetic Resonance (NMR) spectroscopy, in addition to elemental and stable isotope analysis of carbon and nitrogen. Our results show that carbon eroded from areas of higher burn intensity generally had higher concentration of aromatic functional groups, compared to moderate burn intensity areas. Differences in the form of C eroded from areas of different burn intensity and slope steepness can be used as a proxy for determining how fire severity and geomorphology dictate the amount and nature of C eroded from

  8. A THREE-DIMENSIONAL AIR FLOW MODEL FOR SOIL VENTING: SUPERPOSITION OF ANLAYTICAL FUNCTIONS

    EPA Science Inventory

    A three-dimensional computer model was developed for the simulation of the soil-air pressure distribution at steady state and specific discharge vectors during soil venting with multiple wells in unsaturated soil. The Kirchhoff transformation of dependent variables and coordinate...

  9. Exploring the potential for using artificial radionuclides to assess the selective erosion of sediment particles and soil organic matter

    NASA Astrophysics Data System (ADS)

    Greenwood, P.

    2012-04-01

    This communication presents the preliminary results of experimental work to assess the potential for using the artificial gamma-emitting radionuclides, Caesium-134 (134Cs) and Cobalt-60 (60Co), to simulate the particle-size selective sediment redistribution, and hence, of soil organic carbon, on a range of different cultivated hillslope soils from southern England. The concentration of artificial radionuclides and soil organic matter (SOM) in sediment are both subject to a differentiation as a consequence of selective detachment and depositional processes caused by surface-runoff during erosion events on hillslope environments. Unlike soil organic matter, the radionuclides Cs and Co remain stable in sediment, i.e. they remain attached to particles and are not subject to mineralization during transport or after deposition. A priori reasoning suggests, therefore, that artificial radionuclides represent a faithful analogue that can be effectively used to study the movement of particulate soil organic matter through a range of mobilization and transport processes.

  10. Soil Erosion and Sediment Losses from the Ridge Watersheds in the Guánica Bay, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Yuan, Yongping; Taguas, Encarnación; Hu, Wenhui

    2014-05-01

    Puerto Rico faces considerable challenges regarding sustainable land use and effects of land use on adjacent coastal ecosystems and the services they provide. One primary concern is increased sediment loading to reservoirs and ultimately to Guánica Bay and reef areas outside the Bay. Studies by scientists in Puerto Rico have suggested that nutrient and sediment contaminants have increased 5 to 10 fold since pre-colonial levels and an additional 2 to 3 fold in the last 40-50 years (Sturm et al., 2012). Sediment deposition has significantly reduced the storage capacity of several reservoirs, and the associated contaminants and nutrients within the terrestrial soil particles of sediment can stress corals and negatively impact reef health. Sedimentation can also reduce photosynthetic activity of aquatic plants and algae, and increase water-treatment costs for domestic and industrial uses (Estades Hernández, 1997). Therefore, it is important to understand soil erosion and sediment transport processes. In this study, we analyze sediment losses from ridge watersheds of the Guánica Bay and try to understand the main factors causing soil erosion and sediment in those ridge watersheds. Our specific objectives were: 1) to quantify sediment contributions to Guánica Bay and identify sediment sources; 2) seek factors that impact the sediment loss and explore alternative strategies to reduce soil erosion and sediment loading to the reservoirs, Guánica Bay and the coastal zone. It was found that sediment loss in those ridge watersheds was mainly caused by interaction of heavy rainfall (especially the hurricanes) and steep mountainous slopes. Coffee planting increased the risk of soil erosion, which the loss of protective canopy for sun-grown coffee exacerbated. In addition, rainy seasons (February to May and August to November) contributed more than 80% of annual sediment loss. Exploration of different land use scenarios found that coffee land use yielded more sediment per

  11. Modern sedimentation patterns in Laguna de Medina, Southern Spain, derived from lake surface and soil samples

    NASA Astrophysics Data System (ADS)

    van ´t Hoff, Jasmijn; Schröder, Tabea; Reicherter, Klaus; Held, Peter; Melles, Martin

    2016-04-01

    In September 2014 and March 2015, a 25.66 m long sediment core (Co1313) was retrieved from the centre of Laguna de Medina, a small endorheic salt lake in Cádiz, SW Spain. This record covers the last 9.000 years, thus providing an unique archive for Holocene climatic and environmental changes with extraordinary high temporal resolution. For a better understanding of the palaeoenvironmental proxies to be analysed on the sediment core, the modern processes of sediment formation in the lake and its catchment under known environmental conditions were investigated on a set of 46 lake sediment surface samples and 32 soil surface sediment samples from the lake and the close surroundings, respectively. These samples were analysed for bulk mineralogy (XRD), chemical composition (XRF), grain-size distribution (laser scanner), and carbonate, total organic carbon (TOC), nitrogen (TN) and sulphur (TS) contents (elemental analyser). Based on the mineralogical, geochemical and granulometrical data, the lake can be divided into four zones. The northern shore is characterized by particularly high quartz contents and coarse grain sizes. This reflects input from ancient terraces of the Guadalete River that are exposed in that area. The southern shore is characterised by high calcite contents due to sediment supply from the Cretaceous ´Capas rojaś, a series of Subbetic deep-water marl- and limestones. The southeastern and to a lesser extend the northwestern shores show particularly high dolomite contents, reflecting the Triassic dolomites outcroping in the southeastern catchment. The southeastern shore furthermore is also influenced by strong terrestrial input of the Triassic Keuper facies from the most important inlet, Arroyo Fuente Bermeja, as reflected by high contents of Ti, K, Al, Fe, Rb in the lake sediments. The last zone comprises only a small part of the western shore and is characterized by a relatively high gypsum amount. This does not reflect the geology in the catchment

  12. Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

    PubMed

    Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

    2014-03-15

    Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers.

  13. Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

    PubMed

    Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

    2014-03-15

    Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers. PMID:24509365

  14. Sedimentation Time Measurements of Soil Particles by Light Scattering and Determination of Chromium, Lead, and Iron in Soil Samples via ICP

    ERIC Educational Resources Information Center

    Todebush, Patricia Metthe; Geiger, Franz M.

    2005-01-01

    The study of soil samples, using light scattering and Inductively Coupled Plasma spectrometry (ICP) to determine colloid sedimentation rates and the quantity of chromium, lead, and iron in the sample is described. It shows the physical and chemical behavior of solid components in soil, and how such pollutant binding colloid surfaces directly…

  15. Stronger association of polycyclic aromatic hydrocarbons with soot than with char in soils and sediments

    PubMed Central

    Han, Y.M.; Bandowe, B.A.M.; Wei, C.; Cao, J.J.; Wilcke, W.; Wang, G.H.; Ni, H.Y.; Jin, Z.D.; An, Z.S.; Yan, B.Z.

    2016-01-01

    The knowledge of the association of polycyclic aromatic hydrocarbons (PAHs) with organic matter and carbonaceous materials is critical for a better understanding of their environmental transport, fate, and toxicological effects. Extensive studies have been done with regard to the relationship of PAHs with total organic carbon (TOC) and elemental carbon (EC) in different environmental matrices. The relationship between PAHs and the two subtypes of EC, char (combustion residues) and soot (produced via gas-to-particle conversion) also has been tested in field and laboratory experiments using reference materials. However, a direct comparison of associations of PAHs between with char and with soot in real environmental matrices has to our knowledge not yet been reported because of a lack of methodology to differentiate them. In this study, char and soot were measured using the IMPROVE method to test their associations with 12 EPA priority PAHs measured in topsoil samples (N = 22, top 10 cm) collected from the Guanzhong Plain and in surface sediment samples (N = 32, top 5 cm) from the Wei River (central China). In both soils and sediments, Σ12PAHs were more strongly associated with soot than with char, mainly due to the fact that soot and PAHs were produced in the same gas phase during combustion, had a strong affinity for each other, and were transported and deposited together, while char, the combustion residue, was transported differently to PAHs due to its large particle size. Stronger correlations between PAHs and the different carbon fractions (TOC, soot, and char) in sediments than in soils were observed, which is associated with the redistribution of PAHs among the organic matter pools in water because of the processes during soil erosion and sedimentation in the river. PMID:24656973

  16. Runoff losses of sediment and phosphorus from no-till and cultivated soils receiving dairy manure.

    PubMed

    Verbree, David A; Duiker, Sjoerd W; Kleinman, Peter J A

    2010-01-01

    Managing manure in no-till systems is a water quality concern because surface application of manure can enrich runoff with dissolved phosphorus (P), and incorporation by tillage increases particulate P loss. This study compared runoff from well-drained and somewhat poorly drained soils under corn (Zea mays, L.) production that had been in no-till for more than 10 yr. Dairy cattle (Bos taurus L.) manure was broadcast into a fall planted cover crop before no-till corn planting or incorporated by chisel/disk tillage in the absence of a cover crop. Rainfall simulations (60 mm h(-1)) were performed after planting, mid-season, and post-harvest in 2007 and 2008. In both years and on both soils, no-till yielded significantly less sediment than did chisel/disking. Relative effects of tillage on runoff and P loss differed with soil. On the well-drained soil, runoff depths from no-till were much lower than with chisel/disking, producing significantly lower total P loads (22-50% less). On the somewhat poorly drained soil, there was little to no reduction in runoff depth with no-till, and total P loads were significantly greater than with chisel/disking (40-47% greater). Particulate P losses outweighed dissolved P losses as the major concern on the well-drained soil, whereas dissolved P from surface applied manure was more important on the somewhat poorly drained soil. This study confirms the benefit of no-till to erosion and total P runoff control on well-drained soils but highlights trade-offs in no-till management on somewhat poorly drained soils where the absence of manure incorporation can exacerbate total P losses.

  17. Trace metals in the coastal soils developed from estuarine floodplain sediments in the Croatian Mediterranean region.

    PubMed

    Romic, D; Romic, M; Zovko, M; Bakic, H; Ondrasek, G

    2012-08-01

    Fertile soils in the River Neretva estuary were developed by fluvial sedimentation and deposition of the eroded soil material from the karst hills within the catchment. After extensive reclamation, two reclaimed land zones (fluvial terraces and lower-laying terraces) have been delineated, both used for agriculture. The main objectives of this study were to evaluate soil chemical and geochemical properties in reclaimed zones that differ mainly in topography, soil types and agricultural land use. The origin of the trace metals in the arable soils was studied using multivariate statistics, and interpolation maps of trace metals were produced using GIS and geostatistics. Soil trace metal concentrations do not exceed a threshold value established by the Croatian Government regulation, with exception of copper. Comparative analysis of the main soil properties and trace metal concentrations in the study area showed a pronounced spatial variation and differences between two reclaimed zones in soil organic matter content, bioavailable P and total concentrations of Cd and Cu. Factor analysis in the area of the lower-laying terraces showed grouping of bioavailable P and K, organic matter content and pH (negative loading) in the component associated mostly with the land use. In the area of the fluvial terraces, bioavailable P and total Cd were grouped in the same component that may be explained by the traditional small farm agriculture and overuse of mineral fertilizers. In the whole study area, processes of secondary salinization were determined, accompanied by the raised chloride and sodium concentration measured in the saturation soil extract. PMID:22270492

  18. The significance of morphogenetic analysis in the assessment of soil-water conditions in Quaternary sediments

    NASA Astrophysics Data System (ADS)

    Falkowska, Ewa

    2015-10-01

    The landform pattern of the Polish Lowlands, which originated during and after the Warta Glaciation, is closely connected with areal deglaciation and directions of geomorphological landform evolution. Landscape-shaping processes were significant for the creation of sediment configuration and sediment characteristics of particular landforms and thus for properties of sediments. Determination of the relationships between the origin of a landform and its physical/geochemical properties can facilitate the evaluation of geological conditions carried out for land use planning that should take into account the sensitivity of the geological environment (soil, groundwater) to the migration of contaminants. The aim of this research was to find geomorphological means of identifying physicochemical and hydrogeological properties of Quaternary sediments that enable fast and precise assessment of long-term and recent soil-water conditions. The investigations were conducted in two areas of the Polish Lowlands that were formed during the Warta Glaciation. During geological mapping of distinguished landforms, 169 samples of sediments were collected for laboratory testing. The samples were analyzed for particle size, calcium carbonate, organic matter content, pH, permeability coefficient, CEC, and adsorption of Cd and Pb. The results show that these distinguished glacial landforms are characterized by the recurrence of superficial lithological profiles with typical physicochemical parameters. Thus, the morphogenesis of postglacial areas of central Poland formed during the Warta Glaciation has influenced the ability of surface deposits to retain contamination. A total of seven insulation classes of landforms in terms of differentiated insulating abilities of deposits, as well as the ranges of values for each insulating parameter, have been identified.

  19. Thallium occurrence and partitioning in soils and sediments affected by mining activities in Madrid province (Spain).

    PubMed

    Gomez-Gonzalez, M A; Garcia-Guinea, J; Laborda, F; Garrido, F

    2015-12-01

    Thallium (Tl) and its compounds are toxic to biota even at low concentrations but little is known about Tl concentration and speciation in soils. An understanding of the source, mobility, and dispersion of Tl is necessary to evaluate the environmental impact of Tl pollution cases. In this paper, we examine the Tl source and dispersion in two areas affected by abandoned mine facilities whose residues remain dumped on-site affecting to soils and sediments of natural water courses near Madrid city (Spain). Total Tl contents and partitioning in soil solid phases as determined by means of a sequential extraction procedure were also examined in soils along the riverbeds of an ephemeral and a permanent streams collecting water runoff and drainage from the mines wastes. Lastly, electronic microscopy and cathodoluminescence probe are used as a suitable technique for Tl elemental detection on thallium-bearing phases. Tl was found mainly bound to quartz and alumino-phyllosilicates in both rocks and examined soils. Besides, Tl was also frequently found associated to organic particles and diatom frustules in all samples from both mine scenarios. These biogenic silicates may regulate the transfer of Tl into the soil-water system.

  20. Thallium occurrence and partitioning in soils and sediments affected by mining activities in Madrid province (Spain).

    PubMed

    Gomez-Gonzalez, M A; Garcia-Guinea, J; Laborda, F; Garrido, F

    2015-12-01

    Thallium (Tl) and its compounds are toxic to biota even at low concentrations but little is known about Tl concentration and speciation in soils. An understanding of the source, mobility, and dispersion of Tl is necessary to evaluate the environmental impact of Tl pollution cases. In this paper, we examine the Tl source and dispersion in two areas affected by abandoned mine facilities whose residues remain dumped on-site affecting to soils and sediments of natural water courses near Madrid city (Spain). Total Tl contents and partitioning in soil solid phases as determined by means of a sequential extraction procedure were also examined in soils along the riverbeds of an ephemeral and a permanent streams collecting water runoff and drainage from the mines wastes. Lastly, electronic microscopy and cathodoluminescence probe are used as a suitable technique for Tl elemental detection on thallium-bearing phases. Tl was found mainly bound to quartz and alumino-phyllosilicates in both rocks and examined soils. Besides, Tl was also frequently found associated to organic particles and diatom frustules in all samples from both mine scenarios. These biogenic silicates may regulate the transfer of Tl into the soil-water system. PMID:26218566

  1. QUANTITATIVE ENZYME-LINKED IMMUNOSORBENT ASSAY FOR DETERMINATION OF POLYCHLORINATED BIPHENYLS IN ENVIRONMENTAL SOIL AND SEDIMENT SAMPLES

    EPA Science Inventory

    An enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of Aroclors 1242, 1248, 1254, and 1260 in soil and sediments was developed and its performance compared with that of gas chromatography (GC). The detection limits for Aroclors 1242 and 1248 in soil ar...

  2. Soil treatment with hot air (Cultivit) as alternative to methyl bromide.

    PubMed

    Runia, W T; Molendijk, L P G; Neophytou, G; Greenberger, A

    2006-01-01

    A new development in physical soil treatment is the application of hot air. Hot air treatment is based on blowing extremely hot air into rotavating humid soil. The method has been developed and applied commercially in Israel for the last few years. An increased growth response (IGR) was observed in several crops like potato, cauliflower, kohlrabi and the flower Esclepia, when the soil was treated with hot air prior to planting. Scientific trials were performed in Israel and Cyprus to quantify IGR and to evaluate the efficacy against plant-parasitic nematodes. Squash was grown in tunnels on root-knot nematodes (Meloidogyne javanica and M. incognita) infested fields in sandy (Israel) and clay loam (Cyprus) soils. In Israel hot air treatment was compared with metam sodium and methyl bromide and a cold air treated control. In Cyprus hot air treatment was compared with untreated control. Hot air treatment increased squash yield in Israel with 90 % and in Cyprus with 150%. Root assessments showed that after hot air treatment the root-knot nematodes were still able to infest plants and cause galling damage. Nematode counts were not reduced by hot air treatment. It may be concluded that the general concept of soil disinfestation is not applicable to hot air treatment. Any positive effect in yield could not be explained by reduction in nematode populations in soil. Possible chemical and biological changes in the hot air treated soils need to be identified. Further research will determine the possibilities and limitations of this method in other crops and under various climatic conditions.

  3. Daily and seasonal variations in radon activity concentration in the soil air.

    PubMed

    Műllerová, Monika; Holý, Karol; Bulko, Martin

    2014-07-01

    Radon activity concentration in the soil air in the area of Faculty of Mathematics, Physics and Informatics (FMPI) in Bratislava, Slovak Republic, has been continuously monitored since 1994. Long-term measurements at a depth of 0.8 m and short-term measurements at a depth of 0.4 m show a high variability in radon activity concentrations in the soil. The analysis of the data confirms that regular daily changes in radon activity concentration in the soil air depend on the daily changes in atmospheric pressure. It was also found that the typical annual courses of the radon activity concentration in the soil air (with summer minima and winter maxima) were disturbed by mild winter and heavy summer precipitation. Influence of precipitation on the increase in the radon activity concentration in the soil air was observed at a depth of 0.4 m and subsequently at a depth of 0.8 m.

  4. Remediation of saturated soil contaminated with petroleum products using air sparging with thermal enhancement.

    PubMed

    Mohamed, A M I; El-menshawy, Nabil; Saif, Amany M

    2007-05-01

    Pollutants in the form of non-aqueous phase liquids (NAPLs), such as petroleum products, pose a serious threat to the soil and groundwater. A mathematical model was derived to study the unsteady pollutant concentrations through water saturated contaminated soil under air sparging conditions for different NAPLs and soil properties. The comparison between the numerical model results and the published experimental results showed acceptable agreement. Furthermore, an experimental study was conducted to remove NAPLs from the contaminated soil using the sparging air technique, considering the sparging air velocity, air temperature, soil grain size and different contaminant properties. This study showed that sparging air at ambient temperature through the contaminated soil can remove NAPLs, however, employing hot air sparging can provide higher contaminant removal efficiency, by about 9%. An empirical correlation for the volatilization mass transfer coefficient was developed from the experimental results. The dimensionless numbers used were Sherwood number (Sh), Peclet number (Pe), Schmidt number (Sc) and several physical-chemical properties of VOCs and porous media. Finally, the estimated volatilization mass transfer coefficient was used for calculation of the influence of heated sparging air on the spreading of the NAPL plume through the contaminated soil.

  5. Distribution of heavy metals in riverine soils and sediments of the Turia River basin.

    NASA Astrophysics Data System (ADS)

    Andreu, Vicente; Gimeno-García, Eugenia; Pascual, Juan Antonio

    2014-05-01

    Water is a scarce and contested good, and a primary need for the population all over. Rivers are one of the mainsources of freshwater to people but, in the same way, receive both point source and difuse pollution, usually frorm wastewaters and agriculture. However, they are not independent bodies but they influence different associated ecosystems that compound the catchment. Soils of the river banks often acts as the last phase of the diffuse contamination pathways, favouring the contaminants input to the river waters. In this sense, the fluvial sedimentary phase usually acts as a sink of pollutants. Sediments can work as resevoirs that accumulate contaminants fixing them or allowing their decomposition or metabolization. However, environmental or human induced, such as variations in water pH, increases in the turbulence or intensity of the water flow, etc.could favour their release to the environment. In this work, the incidence and distribution of seven heavy metals was monitored in riverine soils and sediments of the Turia River. Along the river course, 22 zones were selected for sampling according different lithologies, land uses, size of populations and the proximity to waste waters treatment plants (WWTPs), from the headwaters to the mouth. The selected metals (Cd, Co, Cr, Cu, Pb, Ni and Zn) were analysed to determine its total and extractable contents in the sediments. Total content of metals was extracted by microwave acid digestion and the extractable fraction by treatment with EDTA. Atomic Absorption Spectrometry, using graphite furnace when necessary, was used for the determination of all metals. Highest values for sediments were mainly observed in zones 10 and 22, close to urban areas, reaching values of 172.86 mg/kg for Pb, or 58.34 mg/kg for Cr. However, zone 2 near in the headwaters of the Alfambra River and supposedly of reference for the River authorities shows the highest values of zinc with 96.96 mg/kg. Regarding the available

  6. Correlations of natural radionuclides in soil with those in sediment from the Danube and nearby irrigation channels.

    PubMed

    Krmar, M; Varga, E; Slivka, J

    2013-03-01

    The correlation between activity concentrations of some natural radionuclides ((238)U, (226)Ra, (232)Th, (40)K) measured in soil and in sediment taken from the Danube River and nearby irrigation channels was studied. The soil samples were collected from the northern part of Serbia and the sediment from the Serbian part of the Danube River and from the surrounding irrigation channels. The correlation between (238)U and other natural radionuclides in irrigation channel sediments was not as good as in the Danube. One of the possible explanations for this weak correlation can be the different chemical dynamics of (238)U in the irrigation channel sediment or changes of the (238)U activity concentration in irrigation channel sediment due to some human activities. The evaluation of ratios of activity concentrations of some natural radionuclides could be a more sensitive method for the determination of contaminant, rather than the straightforward analysis of activity concentrations.

  7. Seasonal exposure to drought and air warming affects soil Collembola and mites.

    PubMed

    Xu, Guo-Liang; Kuster, Thomas M; Günthardt-Goerg, Madeleine S; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

  8. Geochemical distribution of polycyclic aromatic hydrocarbons in soils and sediments of El-Tabbin, Egypt.

    PubMed

    Havelcová, Martina; Melegy, Ahmed; Rapant, Stanislav

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) were extracted from 30 samples (24 soils and 6 stream sediments) collected in El-Tabbin area in the southern part of Greater Cairo, Egypt. Isopleth maps of PAHs clarified the regional variability and identified the most affected regions in the area suffering from high pollution. The total PAH concentrations were 53.4-5558.0 ng g(-1) in the sample extracts. The highest values were found in a soil sample near a coke factory, with the highest concentration of single PAHs, which were 1064.8 ng g(-1) of fluoranthene and 1286.4 ng g(-1) of phenanthrene. The calculated ratios and indexes allowed to elucidate origin of the organic compounds and to identify emission sources. The overall molecular patterns are signatures of pyrolysis of fossil fuels and biomass. Petrogenic contamination was recognised in the sediment samples due to petroleum products deliveries from ships. Also perylene was prominent especially in samples of the River Nile sediments as a diagenetic product of fungi. Other detailed information on petrogenic sources was provided by analysis of alkanes and calculation of alkane ratios. PMID:24053943

  9. Contamination and risk of heavy metals in soils and sediments from a typical plastic waste recycling area in North China.

    PubMed

    Tang, Zhenwu; Zhang, Lianzhen; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

    2015-12-01

    Plastic wastes are increasingly being recycled in many countries. However, available information on the metals released into the environment during recycling processes is rare. In this study, the contamination features and risks of eight heavy metals in soils and sediments were investigated in Wen'an, a typical plastic recycling area in North China. The surface soils and sediments have suffered from moderate to high metal pollution and in particular, high Cd and Hg pollution. The mean concentrations of Cd and Hg were 0.355 and 0.408 mg kg(-1), respectively, in the soils and 1.53 and 2.10 mg kg(-1), respectively, in the sediments. The findings suggested that there is considerable to high potential ecological risks in more than half of the soils and high potential ecological risk in almost all sediments. Although the health risk levels from exposure to soil metals were acceptable for adults, the non-carcinogenic risks to local children exceeded the acceptable level. Source assessment indicated that heavy metals in soils and sediments were mainly derived from inputs from poorly controlled plastic waste recycling operations in this area. The results suggested that the risks associated with heavy metal pollution from plastic waste recycling should be of great concern.

  10. Contamination and risk of heavy metals in soils and sediments from a typical plastic waste recycling area in North China.

    PubMed

    Tang, Zhenwu; Zhang, Lianzhen; Huang, Qifei; Yang, Yufei; Nie, Zhiqiang; Cheng, Jiali; Yang, Jun; Wang, Yuwen; Chai, Miao

    2015-12-01

    Plastic wastes are increasingly being recycled in many countries. However, available information on the metals released into the environment during recycling processes is rare. In this study, the contamination features and risks of eight heavy metals in soils and sediments were investigated in Wen'an, a typical plastic recycling area in North China. The surface soils and sediments have suffered from moderate to high metal pollution and in particular, high Cd and Hg pollution. The mean concentrations of Cd and Hg were 0.355 and 0.408 mg kg(-1), respectively, in the soils and 1.53 and 2.10 mg kg(-1), respectively, in the sediments. The findings suggested that there is considerable to high potential ecological risks in more than half of the soils and high potential ecological risk in almost all sediments. Although the health risk levels from exposure to soil metals were acceptable for adults, the non-carcinogenic risks to local children exceeded the acceptable level. Source assessment indicated that heavy metals in soils and sediments were mainly derived from inputs from poorly controlled plastic waste recycling operations in this area. The results suggested that the risks associated with heavy metal pollution from plastic waste recycling should be of great concern. PMID:26318969

  11. Sediments and Soils Act as Reservoirs for Taxonomic and Functional Bacterial Diversity in the Upper Mississippi River.

    PubMed

    Staley, Christopher; Gould, Trevor J; Wang, Ping; Phillips, Jane; Cotner, James B; Sadowsky, Michael J

    2016-05-01

    In this study, we utilized Illumina next-generation sequencing of 16S rDNA to characterize the bacterial communities in water, sediments, and soils at four sites along the Mississippi River and Minnesota River, in Minnesota, in order to evaluate community exchanges between these habitats. Communities in water and sediment were hypothesized to show greater taxonomic similarity than those in soil, while microbial communities in sediment and soil would show greater functional similarity. Habitat-specific communities showed significant differences in phylogenetic structure and β-diversity (P < 0.001), but site-specific differences in community structures within a single habitat type did not differ greatly (P ≥ 0.083). Community exchange among habitats generally influenced < 5% of the total community composition in a single sample, with the exception of the sediment community at the Minnesota River site, which contributed to a mean of 14% of the microbial community in the water column. Communities from all habitat types were significantly correlated with each other (r = 0.44-0.64, P ≤ 0.004). Furthermore, approximately 33% of the taxonomic units were found in all samples and comprised at least 40% of the bacterial community. Functional annotation of shotgun sequencing data revealed similar functional profiles for sediment and soil communities that were distinct from those in the water. Results of this study suggest that sediments, when disturbed, contribute significantly to bacterial communities in the water and that a core bacterial community may be supported in the soils and sediments. Furthermore, a high degree of functional redundancy results in similar functional profiles in sediment and soil communities. PMID:26879939

  12. Soil erosion and sediment sources in an Ohio watershed using beryllium-7, cesium-137, and lead-210.

    PubMed

    Matisoff, Gerald; Bonniwell, Everett C; Whiting, Peter J

    2002-01-01

    Soil cores and suspended sediments were collected within the Old Woman Creek, Ohio (OWC) watershed following a thunderstorm and analyzed for 7Be, 137Cs, and 210Pb activities to compare the effects of till vs. no-till management on soil erosion and sediment yield. The upper reaches of the watershed draining tilled agricultural fields were disproportionately responsible for the majority of the suspended sediment load compared with lower in the watershed (2.0-7.0 metric tons/km2 [Mg/km2] vs. 1.2-2.6 Mg/km2). About 6 to 10 times more sediment was derived from the subbasins that are predominantly tilled (6.8-12.4 Mg/km2) compared with the subbasins undergoing no-till practices (0.5-1.1 Mg/km2). In undisturbed soils the 210Pb activities decreased with movement toward the bottom of the cores to the constant supported 210Pb value at a depth of about 10 cm. There was a subsurface maximum in 137Cs activity within the top 10 cm. In contrast, the 210Pb and 137Cs distributions in soils that are currently or were previously tilled were nearly homogeneous with depth, reflecting continuing or previous mixing by plowing. The activities of 210Pb and 7Be were linearly correlated and were higher in suspended sediments derived from no-till subbasins than those derived from tilled subbasins, indicating that the soil surface is the source of suspended sediment. This study demonstrates that no-till farming results in decreases in soil erosion and decreases in suspended sediment discharges and that those eroded sediments have a radionuclide signature corresponding to the tillage practice and the depth of erosion.

  13. Soil erosion and sediment sources in an Ohio watershed using beryllium-7, cesium-137, and lead-210.

    PubMed

    Matisoff, Gerald; Bonniwell, Everett C; Whiting, Peter J

    2002-01-01

    Soil cores and suspended sediments were collected within the Old Woman Creek, Ohio (OWC) watershed following a thunderstorm and analyzed for 7Be, 137Cs, and 210Pb activities to compare the effects of till vs. no-till management on soil erosion and sediment yield. The upper reaches of the watershed draining tilled agricultural fields were disproportionately responsible for the majority of the suspended sediment load compared with lower in the watershed (2.0-7.0 metric tons/km2 [Mg/km2] vs. 1.2-2.6 Mg/km2). About 6 to 10 times more sediment was derived from the subbasins that are predominantly tilled (6.8-12.4 Mg/km2) compared with the subbasins undergoing no-till practices (0.5-1.1 Mg/km2). In undisturbed soils the 210Pb activities decreased with movement toward the bottom of the cores to the constant supported 210Pb value at a depth of about 10 cm. There was a subsurface maximum in 137Cs activity within the top 10 cm. In contrast, the 210Pb and 137Cs distributions in soils that are currently or were previously tilled were nearly homogeneous with depth, reflecting continuing or previous mixing by plowing. The activities of 210Pb and 7Be were linearly correlated and were higher in suspended sediments derived from no-till subbasins than those derived from tilled subbasins, indicating that the soil surface is the source of suspended sediment. This study demonstrates that no-till farming results in decreases in soil erosion and decreases in suspended sediment discharges and that those eroded sediments have a radionuclide signature corresponding to the tillage practice and the depth of erosion. PMID:11837444

  14. Spatial analysis of soil erosion and sediment fluxes: a paired watershed study of two Rappahannock River tributaries, Stafford County, Virginia.

    PubMed

    Ricker, Matthew C; Odhiambo, Ben K; Church, Joseph M

    2008-05-01

    Soil erosion is a serious problem in areas with expanding construction, agricultural production, and improper storm water management. It is important to understand the major processes affecting sediment delivery to surficial water bodies in order to tailor effective mitigation and outreach activities. This study analyzes how naturally occurring and anthropogenic influences, such as urbanization and soil disturbance on steep slopes, are reflected in the amount of soil erosion and sediment delivery within sub-watershed-sized areas. In this study, two sub-watersheds of the Rappahannock River, Horsepen Run and Little Falls Run, were analyzed using the Revised Universal Soil Loss Equation (RUSLE) and a sediment delivery ratio (SDR) to estimate annual sediment flux rates. The RUSLE/SDR analyses for Horsepen Run and Little Falls Run predicted 298 Mg/y and 234 Mg/y, respectively, but nearly identical per-unit-area sediment flux rates of 0.15 Mg/ha/y and 0.18 Mg/ha/y. Suspended sediment sampling indicated greater amounts of sediment in Little Falls Run, which is most likely due to anthropogenic influences. Field analyses also suggest that all-terrain vehicle crossings represent the majority of sediment flux derived from forested areas of Horsepen Run. The combined RUSLE/SDR and field sampling data indicate that small-scale anthropogenic disturbances (ATV trails and construction sites) play a major role in overall sediment flux rates for both basins and that these sites must be properly accounted for when evaluating sediment flux rates at a sub-watershed scale.

  15. Soil-based filtration technology for air purification: potentials for environmental and space life support application

    NASA Astrophysics Data System (ADS)

    Nelson, Mark; Bohn, Hinrich

    Soil biofiltration, also known as Soil bed reactor (SBR), technology was originally developed in Germany to take advantage of the diversity in microbial mechanisms to control gases producing malodor in industrial processes. The approach has since gained wider international acceptance and seen numerous improvements, for example, by the use of high-organic compost beds to maximize microbial processes. This paper reviews the basic mechanisms which underlay soil processes involved in air purification, advantages and limitations of the technology and the cur-rent research status of the approach. Soil biofiltration has lower capital and operating/energetic costs than conventional technologies and is well adapted to handle contaminants in moderate concentrations. The systems can be engineered to optimize efficiency though manipulation of temperature, pH, moisture content, soil organic matter and airflow rates. SBR technology was modified for application in the Biosphere 2 project, which demonstrated in preparatory research with a number of closed system testbeds that soil could also support crop plants while also serving as soil filters with air pumps to push air through the soil. This Biosphere 2 research demonstrated in several closed system testbeds that a number of important trace gases could be kept under control and led to the engineering of the entire agricultural soil of Biosphere 2 to serve as a soil filtration unit for the facility. Soil biofiltration, coupled with food crop produc-tion, as a component of bioregenerative space life support systems has the advantages of lower energy use and avoidance of the consumables required for other air purification approaches. Expanding use of soil biofiltration can aid a number of environmental applications, from the mitigation of indoor air pollution, improvement of industrial air emissions and prevention of accidental release of toxic gases.

  16. New species of ice nucleating fungi in soil and air

    NASA Astrophysics Data System (ADS)

    Fröhlich-Nowoisky, Janine; Hill, Thomas C. J.; Pummer, Bernhard G.; Franc, Gray D.; Pöschl, Ulrich

    2014-05-01

    -8°C. The IN seem not be bound to cells because they can be easily washed off the mycelium. They pass through a 0.1 µm filter and can be inactivated by 60°C treatment. Ongoing investigations of various soil and air samples indicate that diverse ice nucleation active fungi from more than one phylum are not only present in air and soil but can also be abundant components of the cultivable community. A recently discovered group of IN fungi in soil was also found to possess easily suspendable IN smaller than 300 kDa. Ice nucleating fungal mycelium may ramify topsoils and release cell-free IN into it. If some of these IN survive decomposition or are adsorbed onto mineral surfaces this contribution will accumulate over time, perhaps to be transported with soil dust and influencing its ice nucleating properties. Thanks for collaboration and support to M.O. Andreae, B. Baumgartner, I. Germann-Müller, T. Godwill, L.E. Hanson, A.T. Kunert, J. Meeks, T. Pooya, S. Lelieveld, J. Odhiambo Obuya, C. Ruzene-Nespoli, and D. Sebazungu. The Max Planck Society (MPG), Ice Nuclei research UnIT (INUIT), the German Research Foundation (PO1013/5-1), and the National Science Foundation (NSF, grant 0841542) are acknowledged for financial support. 1. Fröhlich-Nowoisky, J., et al. (2009) Proc. Natl Acad. Sci., 106, 12814-12819 2. Després, V. R., et al. (2012) Tellus B, 64, 15598 3. Georgakopoulos, D.G., et al. (2009) Biogeosciences, 6, 721-737 4. Pouleur, S., et al. (1992) Appl. Environ. Microbiol. 58, 2960-2964 5. Burrows, S.M., et al. (2009a) Atmos. Chem. Phys., 9, (23), 9281-9297 6. Burrows, S.M., et al. (2009b) Atmos. Chem. Phys., 9, (23), 9263-9280 7. Fröhlich-Nowoisky, J., et al. (2012) Biogeosciences, 9, 1125-1136 8. Huffman A. J. et al. (2013) Atmos. Chem. Phys., 13, 6151-6164

  17. [Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Soils and Sediments in Shunde Waterway, Southern China].

    PubMed

    Cai, Yi-min; Chen, Wei-ping; Peng, Chi; Wang, Tie-yu; Xiao, Rong-bo

    2016-05-15

    Environmental quality of soils and sediments around water source area can influence the safety of potable water of rivers. In order to study the pollution characteristics, the sources and ecological risks of heavy metals Zn, Cr, Pb, Cu, Ni and Cd in water source area, surface soils around the waterway and sediments in the estuary of main tributaries were collected in Shunde, and ecological risks of heavy metals were assessed by two methods of potential ecological risk assessment. The mean contents of Zn, Cr, Pb, Cu, Ni and Cd in the surface soils were 186.80, 65.88, 54.56, 32.47, 22.65 and 0.86 mg · kg⁻¹ respectively, and they were higher than their soil background values except those of Cu and Ni. The mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in the sediments were 312.11, 111.41, 97.87, 92.32, 29.89 and 1.72 mg · kg⁻¹ respectively, and they were higher than their soil background values except that of Ni. The results of principal component analysis illustrated that the main source of Cr and Ni in soils was soil parent materials, and Zn, Pb, Cu and Cd in soils mainly came from wastewater discharge of local manufacturing industry. The six heavy metals in sediments mainly originated from industry emissions around the Shunde waterway. The results of potential ecological risk assessment integrating environmental bioavailability of heavy metals showed that Zn, Cu, Pb and Ni had a slight potential ecological risk. Cd had a slight potential ecological risk in surface soils, but a moderate potential ecological risk in surfaces sediments. Because the potential ecological risk assessment integrating environmental bioavailability of heavy metals took the soil properties and heavy metal forms into account, its results of risks were lower than those of Hakanson methods, and it could avoid overestimating the potential risks of heavy metals.

  18. [Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Soils and Sediments in Shunde Waterway, Southern China].

    PubMed

    Cai, Yi-min; Chen, Wei-ping; Peng, Chi; Wang, Tie-yu; Xiao, Rong-bo

    2016-05-15

    Environmental quality of soils and sediments around water source area can influence the safety of potable water of rivers. In order to study the pollution characteristics, the sources and ecological risks of heavy metals Zn, Cr, Pb, Cu, Ni and Cd in water source area, surface soils around the waterway and sediments in the estuary of main tributaries were collected in Shunde, and ecological risks of heavy metals were assessed by two methods of potential ecological risk assessment. The mean contents of Zn, Cr, Pb, Cu, Ni and Cd in the surface soils were 186.80, 65.88, 54.56, 32.47, 22.65 and 0.86 mg · kg⁻¹ respectively, and they were higher than their soil background values except those of Cu and Ni. The mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in the sediments were 312.11, 111.41, 97.87, 92.32, 29.89 and 1.72 mg · kg⁻¹ respectively, and they were higher than their soil background values except that of Ni. The results of principal component analysis illustrated that the main source of Cr and Ni in soils was soil parent materials, and Zn, Pb, Cu and Cd in soils mainly came from wastewater discharge of local manufacturing industry. The six heavy metals in sediments mainly originated from industry emissions around the Shunde waterway. The results of potential ecological risk assessment integrating environmental bioavailability of heavy metals showed that Zn, Cu, Pb and Ni had a slight potential ecological risk. Cd had a slight potential ecological risk in surface soils, but a moderate potential ecological risk in surfaces sediments. Because the potential ecological risk assessment integrating environmental bioavailability of heavy metals took the soil properties and heavy metal forms into account, its results of risks were lower than those of Hakanson methods, and it could avoid overestimating the potential risks of heavy metals. PMID:27506029

  19. How humic substances dominate mercury geochemistry in contaminated floodplain soils and sediments

    SciTech Connect

    Wallschlaeger, D.; Desai, M.V.M.; Spengler, M.; Windmoeller, C.C.; Wilken, R.D.

    1998-09-01

    The interaction of mercury (Hg) and humic substances (hs) was studied in floodplain topsoils and surface sediments of the contaminated German river Elbe. An intimate coupling exists between the geochemical cycles of Hg and organic carbon (OC) in this ecosystem. Humic substances exert a dominant influence on several important parallel geochemical pathways of Hg, including binding, transformation, and transport processes. Significant differences exist between the Hg-hs associations in floodplains and sediments. Both humic acids (ha) and fulvic acids (fa) contribute to Hg binding in the sediments. In contrast, ultrafiltration experiments proved that Hg in the floodplain soils is almost exclusively bound to very large humic acids (ha) with a nominal molecular weight (MW) > 300,000. Successive cation and anion exchange experiments demonstrated that those Hg-ha complexes are inert toward competition by other cations, and also apparently predominantly electroneutral. Speciation transformation reactions in the solid phase were investigated by sequential extraction and thermal release experiments. Upon addition of Hg model compounds to a sediment matrix, all species were transformed to the same new speciation pattern, regardless of their original speciation. The accompanying alterations in availability and solubility were partially due to interconversion between the different Hg redox states, including Hg(I). Simultaneously, partial transformation of added Hg{sup 2+} into volatile Hg compounds (35% in 10 d) was observed. Finally, Hg association with water-soluble ha continuously increased downstream, indicating that hs play a key role in both lateral and longitudinal Hg transport in the Elbe ecosystem.

  20. Fallout beryllium-7 as a soil and sediment tracer in river basins: current status and needs

    NASA Astrophysics Data System (ADS)

    Taylor, Alex; Blake, Will H.; Smith, Hugh G.; Mabit, Lionel; Keith-Roach, Miranda J.

    2013-04-01

    Beryllium-7 is a cosmogenic radionuclide formed in the upper atmosphere by cosmic ray spallation of nitrogen and oxygen. Its constant natural production and fallout via precipitation coupled with its ability to bind to soil particles have underpinned its application as a sediment tracer. The short half-life of beryllium-7 (53.3 days) lends itself to tracing sediment dynamics over short time periods, thus, enabling assessment of the effect of land use change upon soil redistribution. Although beryllium-7 has been widely applied as a tracer to date, there remain crucial gaps in understanding relating to the assumptions for its use. To further support the application of beryllium-7 as a tracer across a range of environments requires consideration of both the current strengths and shortcomings of the technique to direct research needs. Here we review research surrounding the assumptions underpinning beryllium-7 use as a tracer and identify key knowledge gaps relating to i) the effects of rain shadowing and vegetation interception upon beryllium-7 fallout uniformity at the hillslope-scale; ii) the effect of preferential flow pathways upon beryllium-7 depth distribution in soil and overland flow upon beryllium-7 inventory uniformity and iii) the potential for beryllium-7 desorption in saline and reducing environments. To provide continued support for the use of beryllium-7 as a hillslope and catchment-scale tracer, there is an urgent need to undertake further research to quantify the effect of these factors upon tracer estimates.

  1. The influence of Fe(III) on oil biodegradation in excessively moistened soils and sediments

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.; Trofimov, S. Ya.; Shoba, S. A.

    2015-07-01

    Soils are self-purified from oil slowly, in the north, in particular, where hydromorphic conditions and low temperatures hinder the process. Oxidation of oil hydrocarbons depends on the type of electron acceptors and decreases in the following sequence: denitrification > Mn4+ reduction > Fe3+ reduction > sulfate reduction > methanogenesis. Usually, not all of these redox reactions develop in contaminated excessively moistened soils and sediments. Fe(III) reduction and methanogenesis are the most common: the latter is manifested near the contamination source, while the former develops in less contaminated areas. Fe reduction hinders the methanogenesis. In oil-contaminated areas, Fe reduction is also combined with sulfate reduction, the latter intensifying Fe reduction due to the formation of iron sulfides. Concurrently with oil degradation in excessively moistened soils and sediments, the composition of iron compounds changes due to the increasing Fe(II) share magnetite, as well as siderite and ferrocalcite (in calcareous deposits), and iron sulfides (in S-containing medium) are formed.

  2. Effect of natural organic matter on arsenic release from soils and sediments into groundwater.

    PubMed

    Wang, Suiling; Mulligan, Catherine N

    2006-06-01

    Arsenic (As) contamination in groundwater has received significant attention recently. Natural and anthropogenic sources contribute to the worldwide occurrence of As contamination. As speciation is an important factor related to its toxic and mobile behavior. The release of As from soils and sediments into groundwater is governed by several geophysicochemical processes, of which, As sorption behavior is of principle significance. This review paper summarizes existing information regarding the effects of natural organic matter (NOM) on the fate and mobility of As species in the environment. NOM may enhance the release of As from soils and sediments into the soil solution, thereby facilitating As leaching into the groundwater. The main influencing mechanisms include competition for available adsorption sites, formation of aqueous complexes, and/or changes in the redox potential of site surfaces and As redox speciation. NOM may also serve as binding agents, thereby reducing As mobility. However, comparably little research has been performed on this aspect. Since most investigations have been done on purified minerals under laboratory conditions, further research involving various geological materials under natural environmental conditions is required. Development of proper geochemical conceptual models may provide means of predicting the role of NOM in arsenic leaching and/or immobilization.

  3. The role of soil air composition for noble gas tracer applications in tropical groundwater

    NASA Astrophysics Data System (ADS)

    Mayer, Simon; Jenner, Florian; Aeschbach, Werner; Weissbach, Therese; Peregovich, Bernhard; Machado, Carlos

    2016-04-01

    Dissolved noble gases (NGs) in groundwater provide a well-established tool for paleo temperature reconstruction. However, reliable noble gas temperature (NGT) determination needs appropriate assumptions or rather an exact knowledge of soil air composition. Deviations of soil air NG partial pressures from atmospheric values have already been found in mid latitudes during summer time as a consequence of subsurface oxygen depletion. This effect depends on ambient temperature and humidity and is thus expected to be especially strong in humid tropical soils, which was not investigated so far. We therefore studied NGs in soil air and shallow groundwater near Santarém (Pará, Brazil) at the end of the rainy and dry seasons, respectively. Soil air data confirms a correlation between NG partial pressures, the sum value of O2+CO2 and soil moisture contents. During the rainy season, we find significant NG enhancements in soil air by up to 7% with respect to the atmosphere. This is twice as much as observed during the dry season. Groundwater samples show neon excess values between 15% and 120%. Nearly all wells show no seasonal variations of excess air, even though the local river level seasonally fluctuates by about 8 m. Assuming atmospheric NG contents in soil air, fitted NGTs underestimate the measured groundwater temperature by about 1-2° C. However, including enhanced soil air NG contents as observed during the rainy season, resulting NGTs are in good agreement with local groundwater temperatures. Our presented data allows for a better understanding of subsurface NG variations. This is essential with regard to NG tracer applications in humid tropical areas, for which reliable paleoclimate data is of major importance for modern climate research.

  4. Quantitative trace analysis of fullerenes in river sediment from Spain and soils from Saudi Arabia.

    PubMed

    Sanchís, Josep; Božović, Dalibor; Al-Harbi, Naif A; Silva, Luis F; Farré, Marinella; Barceló, Damià

    2013-07-01

    A quantitative method based on ultrasound-assisted toluene extraction followed by liquid chromatography-electrospray ionization-tandem mass spectrometry for the analysis of C60 and C70 fullerenes, N-methylfulleropyrrolidine, [6, 6]-phenyl C61 butyric acid methyl ester and [6, 6]-thienyl C61 butyric acid methyl ester has been developed. The method was validated using fortified blank river sediments according to the criteria of Commission Decision 2002/657/EC. The method limits of detection ranged from 14 to 290 pg/g, making it suitable for its application in environmental analysis. The method has been applied to investigate fullerene content in 58 soil samples collected from different urban and industrial areas in Saudi Arabia and in river sediment from six different sites in the Llobregat River Basin. In addition, in the case of the Llobregat River, superficial water samples from the same sites of the sediments were collected and analysed using a previous method. In soils from Saudi Arabia, C60-fullerene was the only compound that was detected and quantified in 19% of samples. In the sediments of the Llobregat River, C60-fullerene was also the only one detected (33% of the samples), while in river water, C70-fullerene was the most frequent compound, and it was quantified in 67% of the samples. However, C60-fullerene was present in two of the six samples, but at higher concentrations than C70-fullerene, ranging from 0.9 to 7.8 ng/L. PMID:23545859

  5. Monitoring aggregate disintegration with laser diffraction: A tool for studying soils as sediments

    NASA Astrophysics Data System (ADS)

    Mason, Joseph; Kasmerchak, Chase; Liang, Mengyu

    2016-04-01

    One of the more important characteristics of soil that becomes hillslope, fluvial, or aeolian sediment is the presences of aggregates, which disintegrate at varying rates and to varying degrees during transport. Laser diffraction particle size analyzers allow monitoring of aggregate disintegration as a sample of soil or sediment suspended in water is circulated continuously through the measurement cell (Bieganowski et al., 2010, Clay Minerals 45-23-34; Mason et al., Catena 87:107-118). Mason et al. (2011) applied this approach to aeolian sedimentary aggregates (e.g. clay pellets eroded from dry lakebeds), immersing dry samples in DI water and circulating them through a Malvern Mastersizer 2000 particle size analyzer for three hours while repeated size distribution (SD) measurements were made. A final measurement was made after sonication and treatment with Na-metaphosphate. In that study, most samples approached a steady SD within three hours, which included both primary mineral grains and persistent aggregates. The disintegration process could be modeled with a first-order rate law representing the disintegration of a single population of aggregates. A wide range of model parameters were observed among the samples studied, and it was suggested that they could be useful in predicting the behavior of these aggregates, under rainfall impact and during slopewash or fluvial transport. Addition of Ca++ to the suspension altered aggregate behavior in some but not all cases. We applied the same method to dry, unground material from upper horizons of soils sampled along a bioclimatic gradient in northern Minnesota, USA, all formed in lithologically similar glacigenic sediment. These ranged from Alfisols (Luvisols) formed under forest since the last deglaciation, to Alfisols under forest that more recently replaced grassland, and Mollisols (Chernozems) that formed entirely under grassland vegetation. Few of these soil samples approached a steady SD within three hours, and

  6. Polycyclic aromatic hydrocarbons in water, sediment and soil of the Songhua River Basin, China.

    PubMed

    Ma, Wan-Li; Liu, Li-Yan; Qi, Hong; Zhang, Zi-Feng; Song, Wei-Wei; Shen, Ji-Min; Chen, Zhong-Lin; Ren, Nan-Qi; Grabuski, Josey; Li, Yi-Fan

    2013-10-01

    The Songhua River is the third largest river in China and the primary source of drinking and irrigation water for northeastern China. The distribution of 16 priority polycyclic aromatic hydrocarbons (PAHs) in water [dissolved water (DW) and suspended particulate matter (SPM)], sediment, and soil in the river basin was investigated, and the associated risk of cancer from these PAHs was also assessed. The total concentration of PAHs ranged from 13.9 to 161 ng L(-1) in DW, 9.21 to 83.1 ng L(-1) in SPM, 20.5 to 632 ng g(-1) dw (dry weight) in sediment, and from 30.1 to 870 ng g(-1) dw in soil. The compositional pattern of PAHs indicated that three-ring PAHs were predominant in DW and SPM samples, while four-ring PAHs dominated in sediment and soil samples. The spatial distribution of PAHs revealed some site-specific sources along the river, with principal component analysis indicating that these were from pyrogenic sources (such as coal and biomass combustion, and vehicle emissions) and coke oven emission distinguished as the main source of PAHs in the Songhua River Basin. Based on the ingestion of PAH-contaminated drinking water from the Songhua River, cancer risk was quantitatively estimated by combining the Incremental Lifetime Cancer Risk assessment model and BaP-equivalent concentration for five age groups of people (adults, teenagers, children, toddlers, and infants). Overall, the results suggest that the estimated integrated lifetime cancer risk for all groups was in acceptable levels. This study is the first attempt to provide information on the cancer risk of PAHs in drinking water from the Songhua River.

  7. Hysteresis in the sorption and desorption of hydrophobic organic contaminants by soils and sediments. 2. Effects of soil organic matter heterogeneity

    NASA Astrophysics Data System (ADS)

    Weber, Walter J.; Huang, Weilin; Yu, Hong

    1998-05-01

    Sorption and desorption equilibria were measured for phenanthrene and 12 different soil and sediment samples using an experimental protocol described in the companion paper of this two-part series. Ten of the 12 sorbents studied were found to exhibit statistically significant sorption-desorption hysteresis, with those containing diagenetically-altered soil organic matter (kerogens) doing so to greater extents than those containing geologically-younger humic soil organic matter. Correlations between the extent of hysteresis and the characteristics of 13C-NMR spectra indicate that particle-scale soil organic matter heterogeneity significantly affects this phenomenon. The experimental observations are mechanistically consistent with a conceptual model based on polymer sorption theory, the Dual Reactive Domain Model (DRDM). The work reinforces the general suitability of the DRDM for characterizing sorption-desorption interactions between hydrophobic organic contaminants and soils and sediments.

  8. Earthworms as colonisers: primary colonisation of contaminated land, and sediment and soil waste deposits.

    PubMed

    Eijsackers, H

    2010-03-15

    This paper reviews the role of earthworms in the early colonisation of contaminated soils as well as sediment and waste deposits, which are worm-free because of anthropogenic activities such as open-cast mining, soil sterilisation, consistent pollution or remediation of contaminated soil. Earthworms live in close interaction with their soil environment and are able to change it considerably by their burrowing and litter comminuting behaviour. While earthworms have been studied extensively, several questions still remain unanswered such as: What are the characteristics of successful early colonisers? Do they function well in dispersal, individual establishment or population growth? Do the negative environmental conditions in these kinds of anthropogenic soils hamper colonization or are these colonizers relatively resistant to it? To what extent does colonization change the characteristics of the colonized substrate? In short, do earthworms impact the soil? In this paper, the characteristics that make earthworms successful colonisers are briefly described as well as which species are the most successful and under what circumstances, and what do earthworms contribute to the total process of succession. We propose that it is not so much eco-type or r-K strategy that govern success and succession of earthworm colonisation but rather environmental flexibility not only towards pH, desiccation, and temperature but also towards contaminants such as heavy metals. Moreover, the formation of an organic litter layer, in close connection with re-vegetation of the area, is essential for establishing earthworm populations, which, at first, are mainly superficially and shallow active species. The burrowing and organic matter digesting activity of these earthworms changes the upper soil to a well mixed humus layer suitable for deep burrowing earthworm species.

  9. FEASIBILITY OF USING SEQUENTIAL EXTRACTION TECHNIQUES FOR ARSENIC AND SELENIUM IN SOILS AND SEDIMENTS.

    USGS Publications Warehouse

    Gruebel, Karen A.; Davis, James A.; Leckie, James O.

    1988-01-01

    Laboratory experiments were conducted with well-characterized minerals to test the applicability of selective extraction schemes for Se and As partitioning in soils and sediments. Two specific steps were tested: the reductive dissolution of amorphous iron oxides and the oxidation of organic material. Selenium and As associated with amorphous iron oxides were usually not found in solution after reductive dissolution, due to readsorption onto other minerals unaffected by the extractant. Oxidants intended to dissolve organic material also oxidized Se(IV) adsorbed on a mineral to Se(VI), causing the release of Se(VI) to the extractant solution.

  10. Availability of polycyclic aromatic hydrocarbons to earthworms (Eisenia andrei, Oligochaeta) in field-polluted soils and soil-sediment mixtures.

    PubMed

    Jager, Tjalling; Baerselman, Rob; Dijkman, Ellen; de Groot, Arthur C; Hogendoorn, Elbert A; de Jong, Ad; Kruitbosch, Jantien A W; Peijnenburg, Willie J G M

    2003-04-01

    The bioavailability of polycyclic aromatic hydrocarbons (PAHs) for earthworms (Eisenia andrei) was experimentally determined in seven field-polluted soils and 15 soil-sediment mixtures. The pore-water concentration of most PAHs was higher than predicted. However, most of the compound was associated with dissolved organic carbon (DOC) and not directly available for uptake by earthworms. The apparent sorption could be reasonably predicted on the basis of interactions with DOC; however, the biota-soil accumulation factors (BSAFs) for earthworms were up to two orders of magnitude lower than predicted by equilibrium partitioning. The large variability between sites was not fully explained by differences in sorption. Experimental results indicate that the pool of freely dissolved PAHs in the pore water became partially depleted because of uptake by the earthworms and that bioaccumulation is thus also influenced by the kinetics of PAH desorption and mass transport. A pilot study with Lumbricus rubellus showed that steady-state body residues were well correlated to E. andrei. Current results show that depositing dredge spoil on land may lead to increased bioavailability of the lower-molecular-weight PAHs. However, risk assessment can conservatively rely on equilibrium partitioning, but accurate prediction requires quantification of the kinetics of bioavailability. PMID:12685711

  11. Use of combined air sparging and soil vacuum extraction (AS/SVE) and groundwater recovery and treatment as remedial alternatives for dissolved DNAPL recovery

    SciTech Connect

    Sturdivant, R. Jr.; Fulton, G.A. Jr.; Bains, F.E.

    1995-10-01

    Corrective action has been implemented to address a dissolved dense non-aqueous phase liquid (DNAPL) plume in the vicinity of a former waste impoundment at the Paxon Polymer Company facility, located north of Baton Rouge, Louisiana. Assessment activities focused on the characterization of the geologic and hydrologic properties of the sediments underlying the area of investigation and the impact of the dissolved DNAPL plume to the soils and groundwater. Geologic characterization revealed that the facility is underlain by Quaternary age sediments consisting of mixtures of fine-grained sands, silt, and clay. Two hydrologic units were identified within the shallow sediments which are referred to as the Upper Permeable Zone and Second Permeable Zone. The investigation focused on the impacted soils and groundwater of the Upper and Second Permeable Zones. The Upper and Second Permeable Zones were characterized hydrologically to determine the most applicable remedial alternative for addressing the dissolved DNAPL plume. Pilot tests consisting of soil vacuum extraction (SVE), combined air sparging with SVE (AS/SVE), and groundwater recovery were performed. Evaluation of these remedial technology alternatives resulted in the selection of the combined AS/SVE system alternative for the Upper Permeable Zone and the groundwater recovery alternative for the Second Permeable Zone. Recovered off-gas from the combined AS/SVE treatment system from the Upper Permeable Zone is treated through use of a granular activated carbon unit, while recovered groundwater form the Second Permeable Zone is treated by use of a low-profile air stripper.

  12. New species of ice nucleating fungi in soil and air

    NASA Astrophysics Data System (ADS)

    Froehlich, Janine; Hill, Tom; Franc, Gary; Poeschl, Ulrich

    2013-04-01

    Primary biological aerosol particles (PBAP) are ubiquitous in the atmosphere (1). Several types of PBAP have been identified as ice nuclei (IN) that can initiate the formation of ice at relatively high temperatures (2, 3). The best-known biological IN are common plant-associated bacteria. The IN activity of these bacteria is due to a surface protein on the outer cell membrane that catalyses ice formation, for which the corresponding gene has been identified and detected by DNA analysis (2). Fungal spores or hyphae can also act as IN, but the biological structures responsible for their IN activity have not yet been elucidated. Furthermore, the abundance, diversity, sources, seasonality, properties, and effects of fungal IN in the atmosphere have neither been characterized nor quantified. Recent studies have shown that airborne fungi are highly diverse (1), and that atmospheric transport leads to efficient exchange of species among different ecosystems (4, 5). The results presented in Fröhlich-Nowoisky et al. 2012 (6) clearly demonstrate the presence of geographic boundaries in the global distribution of microbial taxa in air, and indicate that regional differences may be important for the effects of microorganisms on climate and public health. Thus, the objective of this study is the identification and quantification of ice nuclei-active fungi in and above ecosystems, and the unraveling of IN-active structures in fungi. Results obtained from the analysis of various soil and air samples and the presence of new fungal ice active species will be revealed. Thanks for collaboration and support to M.O. Andreae, J.-D. Förster, I. Germann-Müller, L.E. Hanson, S. Lelieveld, J. Odhiambo Obuya, T. Pooya, and C. Ruzene-Nespoli. The Max Planck Society (MPG), Ice Nuclei research UnIT (INUIT), and the German Research Foundation (PO1013/5-1) are acknowledged for financial support. 1. Fröhlich-Nowoisky, J., et al. (2009) Proc. Natl Acad. Sci., 106, 12814-12819 2. Georgakopoulos

  13. Magnetic Characterization of Stream-Sediments From Buenos Aires Province, Argentina, Affected by Pollution

    NASA Astrophysics Data System (ADS)

    Chaparro, M. A.; Sinito, A. M.; Bidegain, J. C.; Gogorza, C. S.; Jurado, S.

    2001-12-01

    A wide urban area from Northeast of Buenos Aires Province is exposed to an important anthropogenic influence, mainly due to industrial activity. In this two water streams were chosen: one of them (Del Gato stream, G) next to La Plata City and the another one (El Pescado stream, P) on the outskirts of the city. Both streams have similar characteristics, although the first one (G) has a higher input of pollutants (fluvial effluents, fly ashes, solid wastes, etc.) than the last one (P). Sediments analyzed in this work are limes from continental origin of PostPampeano (Holocene). Although, some cores were affected by sandy-limy sediments with mollusc valves from Querandino Sea (Pleistocene - later Holocene) and limy sediments of chestnut color with calcareous concretions from the Ensenadense. Magnetic measurements and geochemical studies were carried out on the samples. Among the magnetic parameters, specific susceptibility (X), X frequency-dependence (Xfd%), X temperature-dependence, Natural Remanent Magnetization (NRM), Isothermal Remanent Magnetization (IRM), Saturation IRM (SIRM), coercivity of remanence (Bcr), S ratio and SIRM/X ratio, Anhysteric Remanent Magnetization (ARM), Magnetic and Thermal Demagnetization were studied. The magnetic characteristics for both sites indicate the predominance of magnetically soft minerals on G site and relatively hard minerals on P site. Magnetite is the main magnetic carrier, Pseudo Single Domain and Single Domain grains were found. Chemical studies show (in some cases) a high concentration for some heavy metals (Pb, Cu, Zn, Ni and Fe) on the upper 22-cm. Contents of heavy metals and ARM were correlated. Very good correlation (R> 0.81) is found for Cu, Zn, Ni, Fe and the sum (of Pb, Cu, Zn and Ni), and a weaker correlation for Pb.

  14. What's in a beach? Soil micromorphology of sediments from the Lower Paleolithic site of 'Ubeidiya, Israel.

    PubMed

    Mallol, Carolina

    2006-08-01

    A micromorphological study of archaeological sediments from the early Pleistocene site of 'Ubeidiya (Jordan Valley, Israel) was conducted to provide microenvironmental detail for the hominin occupation contexts and investigate site formation issues. Previous research shows that the hominin groups occupied the marshes and pebbly beaches at the shores of a lake during a regressive period, but given that some portions of the lithic and faunal assemblages are abraded and others fresh, there remains a question of whether the archaeological assemblages are in situ or reworked, and if reworked, by what mechanisms and from where. The rates of sedimentation within the regressive cycle, by which we can learn about the frequency and duration of exposed surfaces amenable for hominin occupation is also unknown. Finally, the artificial nature of some of the pebbly layers has been questioned. The micromorphological analysis yielded the identification of twelve microfacies; the majority of these represent fluvially derived floodplain soils or distal mudflow deposits, and a minor number are sediments of lacustrine origin: mudflats and shallow subaqueous sediments. These represent the natural habitats of the 'Ubeidiya hominins and might serve as a reference to similar contexts of other early hominin sites. The sedimentary model proposed here entails the rapid deposition of fluvially derived low-energy sediments at and around the shoreline, followed by prolonged periods of exposure, during which surfaces stabilized within a relatively wet, marshy environment. This interpretation suggests that the abraded portions of the archaeological assemblages are a result of prolonged surface exposure rather than high-energy transport from a distant source or to wave reworking at the shoreline, and supports the consideration of these assemblages as archaeological palimpsests, with locally reworked fresh and abraded elements. No micromorphological evidence supporting anthropogenic agency in the

  15. An improved protocol for DNA extraction from alkaline soil and sediment samples for constructing metagenomic libraries.

    PubMed

    Verma, Digvijay; Satyanarayana, T

    2011-09-01

    An improved single-step protocol has been developed for extracting pure community humic substance-free DNA from alkaline soils and sediments. The method is based on direct cell lysis in the presence of powdered activated charcoal and polyvinylpolypyrrolidone followed by precipitation with polyethyleneglycol and isopropanol. The strategy allows simultaneous isolation and purification of DNA while minimizing the loss of DNA with respect to other available protocols for metagenomic DNA extraction. Moreover, the purity levels are significant, which are difficult to attain with any of the methods reported in the literature for DNA extraction from soils. The DNA thus extracted was free from humic substances and, therefore, could be processed for restriction digestion, PCR amplification as well as for the construction of metagenomic libraries. PMID:21519906

  16. Organochlorine pesticides and polychlorinated biphenyls in surface soils of Novi Sad and bank sediment of the Danube River.

    PubMed

    Skrbic, Biljana; Cvejanov, Jelena; Durisic-Mladenovic, Natasa

    2007-01-01

    The contents of 16 organochlorine pesticides (OCPs) and six so-called indicator polychlorinated biphenyls (PCBs) were determined in the surface zone (0-5 cm) of soil and sediment samples, taken from different locations in the city of Novi Sad, capitol of Vojvodina Province (North of the Serbia) covering residential and commercial area, recreational and arable zone. The total organochlorine pesticides concentration in soil varied from 2.63 to 31.78 ng g(-1) dry weight, while the level in sediment was 10.35 ng g(-1) dry weight. Maximum content of identified individual organochlorine pesticide in soil samples was 10.40 ng g(-1) dry weight for p, p-DDE in the market garden and 6.31 ng g(-1) dry weight for p, p'-DDT in sediment of the Danube River, although their application is restricted in Serbia. Some of investigated PCBs were identified only in the soil samples from a park-school backyard in the city downtown (0.32 ng g(-1) dry weight) and market garden (0.22 ng g(-1) dry weight), and also in sediment sample from left bank of the Danube River (0.41 ng g(-1) dry weight). Data of the OCPs and PCBs present in this study were compared with the ones found for soils and river sediments throughout the world, and with limit values set by soil and sediment quality guidelines. Also, correlation between the levels of certain pesticides and soil characteristics (organic matter, pH and clay content) was investigated.

  17. Trace elements and Pb isotopes in soils and sediments impacted by uranium mining.

    PubMed

    Cuvier, A; Pourcelot, L; Probst, A; Prunier, J; Le Roux, G

    2016-10-01

    The purpose of this study is to evaluate the contamination in As, Ba, Co, Cu, Mn, Ni, Sr, V, Zn and REE, in a high uranium activity (up to 21,000Bq∙kg(-1)) area, downstream of a former uranium mine. Different geochemical proxies like enrichment factor and fractions from a sequential extraction procedure are used to evaluate the level of contamination, the mobility and the availability of the potential contaminants. Pb isotope ratios are determined in the total samples and in the sequential leachates to identify the sources of the contaminants and to determine the mobility of radiogenic Pb in the context of uranium mining. In spite of the large uranium contamination measured in the soils and the sediments (EF≫40), trace element contamination is low to moderate (2sediments/soils, implying an enhanced potential availability. Even if no Pb enrichment is highlighted, the Pb isotopic signature of the contaminated soils is strongly radiogenic. Measurements performed on the sequential leachates reveal inputs of radiogenic Pb in the most mobile fractions of the contaminated soil. Inputs of low-mobile radiogenic Pb from mining activities may also contribute to the Pb signature recorded in the residual phase of the contaminated samples. We demonstrate that Pb isotopes are efficient tools to trace the origin and the mobility of the contaminants in environments affected by uranium mining.

  18. Sorption of toluene by humic acids derived from lake sediment and mountain soil at different pH.

    PubMed

    Chang Chien, S W; Chen, C Y; Chang, J H; Chen, S H; Wang, M C; Mannepalli, Madhava Rao

    2010-05-15

    Contamination of soil and groundwater with BTEX compounds (benzene, toluene, ethylbenzene, and xylene) depends on the sorption behavior of these compounds by soil organic matter (SOM) and humic acids (HAs). In this study sorption of toluene by HAs extracted from lake sediment and mountain soil was investigated. HA suspensions were adjusted to pH 4.00, 6.00, or 8.00 and made to the concentration of 200 mg L(-1). Each HA suspension or solution was subjected to particle size analysis using high performance particle sizer (HPPS). The particle size of HA from lake sediment was around 1000-1200 nm while that from mountain soil was 220-320 nm at suspension pH 4.00. Kinetic studies showed that sorption of toluene by the two HAs followed pseudo-first-order and mainly pseudo-zero-order kinetics. At suspension pH 4.00, the sorption of toluene by the two HAs was best described by Langmuir and Temkin adsorption isotherm models. Further, sorption of toluene by the lake sediment HA was significantly greater than that by mountain soil HA. It was thus suggested that the lake sediment HA with larger particle size may develop beneficially chemical conformation for sorption of toluene and related compounds in soil and associated environments.

  19. Strategies for Treating and Dewatering Contaminated Soils and Sediments Simultaneously - 13389

    SciTech Connect

    Bickford, Jody; Foote, Martin

    2013-07-01

    MSE Technology Applications, Inc. (MSE) was asked to perform a series of treatability studies by Global Technologies, Inc. (Global) and M{sup 2} Polymer Technologies, Inc. (M{sup 2} Polymer) using Global's metal treatment agent, Molecular Bonding System (MBS) and M{sup 2} Polymer's super-absorbent polymer, Waste Lock 770 (WL-770). The primary objective of the study was to determine if the two products could be used as a one-step treatment process to reduce the leachability of metals and de-water soils and/or sediments simultaneously. Three phases of work were performed during the treatability study. The first phase consisted of generating four bench-scale samples: two treated using only MBS and two treated using only WL- 770, each at variable concentrations. The second phase consisted of generating nine bench-scale samples that were treated using MBS and WL-770 in combination with three different addition techniques. The third phase consisted of generating four intermediate-scale samples that were treated using MBS and WL-770 simultaneously. The soils used in the treatability study were collected at the Mike Mansfield Advanced Technology Center in Butte, Montana. The collected soils were screened at 4 mesh (4.75 millimeters (mm)) to remove the coarse fraction of the soil and spiked with metallic contaminants of lead, cadmium, nickel, mercury, uranium, chromium, and zinc. (authors)

  20. Influence of flooding and metal immobilising soil amendments on availability of metals for willows and earthworms in calcareous dredged sediment-derived soils.

    PubMed

    Vandecasteele, Bart; Du Laing, Gijs; Lettens, Suzanna; Jordaens, Kurt; Tack, Filip M G

    2010-06-01

    Soil amendments previously shown to be effective in reducing metal bioavailability and/or mobility in calcareous metal-polluted soils were tested on a calcareous dredged sediment-derived soil with 26 mg Cd/kg dry soil, 2200 mg Cr/kg dry soil, 220 mg Pb/kg dry soil, and 3000 mg Zn/kg dry soil. The amendments were 5% modified aluminosilicate (AS), 10% w/w lignin, 1% w/w diammonium phosphate (DAP, (NH4)2HPO4), 1% w/w MnO, and 5% w/w CaSO4. In an additional treatment, the contaminated soil was submerged. Endpoints were metal uptake in Salix cinerea and Lumbricus terrestris, and effect on oxidation-reduction potential (ORP) in submerged soils. Results illustrated that the selected soil amendments were not effective in reducing ecological risk to vegetation or soil inhabiting invertebrates, as metal uptake in willows and earthworms did not significantly decrease following their application. Flooding the polluted soil resulted in metal uptake in S. cinerea comparable with concentrations for an uncontaminated soil. PMID:20347195

  1. Observations on long-term air-soil exchange of organic contaminants.

    PubMed

    Jones, K C

    1994-09-01

    Evidence for long-term changes in the soil composition of selected organic compounds, brought about by exchanges with the atmosphere, is briefly reviewed. In the case of some compounds - such as benzo(a)pyrene and octachlorodibenzo-p-dioxin, soils may be significant long-term environmental sinks for atmospherically-derived material. In other cases - such as phenanthrene and some of the lighter PCBs, de-gassing or volatilisation from soil back to the air can occur under certain conditions. Hence the soil may act as a "short-term" sink, and a potential source to atmosphere. Indeed, for some 'semi-volatile' compounds used in large quantities in the past - such as PCBs, soil outgassing may actually be an extremely important source to contemporary air. Furthermore, soil outgassing from areas of former high use may provide an important driving mechanism for continued "global cycling" of a range of semi-volatile organochlorine compounds.

  2. Organic persistent toxic substances in soils, waters and sediments along an altitudinal gradient at Mt. Sagarmatha, Himalayas, Nepal.

    PubMed

    Guzzella, Licia; Poma, Giulia; De Paolis, Adolfo; Roscioli, Claudio; Viviano, Gaetano

    2011-10-01

    Persistent Organic Pollutants (POPs) and Polycyclic Aromatic Hydrocarbons (PAHs) are important classes of compounds of serious environmental concern. These compounds were measured in waters, sediments and soils from several high altitude sites in the Sagarmatha National Park (Nepal) and included in the Himalayan ridge. In water samples, low-level substituted PCBs and PBDEs, along with more volatile PAHs, were the most common contaminants. In sediment and soil samples, the PCB profile was mainly composed of medium-level chlorinated congeners and significantly correlated with altitude. The PAH profile for water and soil samples showed the main contribution of pyrogenic PAHs due to emissions of solid combustion, whereas the profile for sediments indicated the main contribution of pyrogenic PAHs from gasoline emissions. The PAH levels measured in Himalayan samples must be considered as low to medium contaminated, whereas the regarded Himalayan stations can be considered undisturbed remote areas concerning PCB, PBDE and OC compounds. PMID:21752503

  3. SIP metagenomics identifies uncultivated Methylophilaceae as dimethylsulphide degrading bacteria in soil and lake sediment

    PubMed Central

    Eyice, Özge; Namura, Motonobu; Chen, Yin; Mead, Andrew; Samavedam, Siva; Schäfer, Hendrik

    2015-01-01

    Dimethylsulphide (DMS) has an important role in the global sulphur cycle and atmospheric chemistry. Microorganisms using DMS as sole carbon, sulphur or energy source, contribute to the cycling of DMS in a wide variety of ecosystems. The diversity of microbial populations degrading DMS in terrestrial environments is poorly understood. Based on cultivation studies, a wide range of bacteria isolated from terrestrial ecosystems were shown to be able to degrade DMS, yet it remains unknown whether any of these have important roles in situ. In this study, we identified bacteria using DMS as a carbon and energy source in terrestrial environments, an agricultural soil and a lake sediment, by DNA stable isotope probing (SIP). Microbial communities involved in DMS degradation were analysed by denaturing gradient gel electrophoresis, high-throughput sequencing of SIP gradient fractions and metagenomic sequencing of phi29-amplified community DNA. Labelling patterns of time course SIP experiments identified members of the Methylophilaceae family, not previously implicated in DMS degradation, as dominant DMS-degrading populations in soil and lake sediment. Thiobacillus spp. were also detected in 13C-DNA from SIP incubations. Metagenomic sequencing also suggested involvement of Methylophilaceae in DMS degradation and further indicated shifts in the functional profile of the DMS-assimilating communities in line with methylotrophy and oxidation of inorganic sulphur compounds. Overall, these data suggest that unlike in the marine environment where gammaproteobacterial populations were identified by SIP as DMS degraders, betaproteobacterial Methylophilaceae may have a key role in DMS cycling in terrestrial environments. PMID:25822481

  4. Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction.

    PubMed

    Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk; Halling-Sørensen, Bent; Björklund, Erland

    2013-09-13

    A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid chromatography coupled to tandem mass spectrometry applying electrospray ionisation for detection. The samples were freeze-dried prior to extraction. The absolute recoveries for soil and sediment ranged from 71 to 123% (relative standard deviation (RSDs) below 16%) and in the range 94-133% (RSDs 9-35%) for poultry manure. The final method allowed for the detection of four ionophores down to a few hundred ngkg(-1) in natural solid matrices with limit of quantifications (LOQs) being 0.96, 0.87, 0.98, and 0.64μgkg(-1) in soil for lasalocid, monensin, salinomycin, and narasin, respectively. Corresponding LOQs in sediment were 1.28, 1.34, 1.39, and 0.78μgkg(-1) for the respective ionophores, while in manure the LOQs were 0.98, 1.01, 1.45, and 1.01μgkg(-1).

  5. SIP metagenomics identifies uncultivated Methylophilaceae as dimethylsulphide degrading bacteria in soil and lake sediment.

    PubMed

    Eyice, Özge; Namura, Motonobu; Chen, Yin; Mead, Andrew; Samavedam, Siva; Schäfer, Hendrik

    2015-11-01

    Dimethylsulphide (DMS) has an important role in the global sulphur cycle and atmospheric chemistry. Microorganisms using DMS as sole carbon, sulphur or energy source, contribute to the cycling of DMS in a wide variety of ecosystems. The diversity of microbial populations degrading DMS in terrestrial environments is poorly understood. Based on cultivation studies, a wide range of bacteria isolated from terrestrial ecosystems were shown to be able to degrade DMS, yet it remains unknown whether any of these have important roles in situ. In this study, we identified bacteria using DMS as a carbon and energy source in terrestrial environments, an agricultural soil and a lake sediment, by DNA stable isotope probing (SIP). Microbial communities involved in DMS degradation were analysed by denaturing gradient gel electrophoresis, high-throughput sequencing of SIP gradient fractions and metagenomic sequencing of phi29-amplified community DNA. Labelling patterns of time course SIP experiments identified members of the Methylophilaceae family, not previously implicated in DMS degradation, as dominant DMS-degrading populations in soil and lake sediment. Thiobacillus spp. were also detected in (13)C-DNA from SIP incubations. Metagenomic sequencing also suggested involvement of Methylophilaceae in DMS degradation and further indicated shifts in the functional profile of the DMS-assimilating communities in line with methylotrophy and oxidation of inorganic sulphur compounds. Overall, these data suggest that unlike in the marine environment where gammaproteobacterial populations were identified by SIP as DMS degraders, betaproteobacterial Methylophilaceae may have a key role in DMS cycling in terrestrial environments.

  6. Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

    DOEpatents

    Golden, Jeffry

    2007-02-13

    A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

  7. Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

    DOEpatents

    Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

    2000-01-01

    A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacting a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

  8. Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

    DOEpatents

    Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

    2003-05-27

    A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

  9. Variations in clay mineralogy and sediment texture of salt marsh soils on the Eastern Shore of Virginia

    SciTech Connect

    Robinson, S.E.; Furman, T. . Dept. of Environmental Sciences)

    1993-03-01

    On the Eastern Shore of VA, relative sea level rise has resulted in encroachment of marsh onto upland areas. The amount and type of sediment determines the morphologic environment of the system: lagoon, mudflat, low marsh, high marsh or upland. This research is part of a study to examine the relationship between marsh soil characteristics and the production of Spartina alterniflora. The productivity of marsh vegetation depends on the import and entrapment of sediments that maintain marsh elevation and control water and nutrient availability. This work focused on distribution patterns of sediment texture and mineralogy. One meter deep cores were taken at marsh sites with 10 cm intervals homogenized for analysis. In order to distinguish potential sediment sources, samples were also taken from upland soil pits on the mainland and dredged one-half mile seaward of the barrier islands. Samples have undergone size analysis with a hydrometer and the clay fraction has been analyzed by XRD. Results from the marsh surface indicate large variations in sediment texture, but only slight differences in clay mineralogy between marshes. Barrier island marshes contain a higher average sand content than mainland marshes because of their closer proximity to barrier island beaches and inputs from overwash deposits. The clay minerals found in all marsh surface deposits are illite and chlorite, indicative of oceanic clays. The clay mineralogy of upland soils (kaolinite, chlorite, illite, vermiculite mixed-layer clay) differs from marsh surface clays, indicating that recent sediment deposited on the marsh surface is no upland soil but rather material brought in through tidal inlets. The sediment texture and clay mineralogy at different depths varies as a function of the past geomorphic and depositional history of the site. These data will be used to determine the timing of marsh development on flooded upland sites and to determine the pre-Holocene source of inorganic sediment inputs.

  10. Heavy metals in sediments, soils, and aquatic plants from a secondary anabranch of the three gorges reservoir region, China.

    PubMed

    Gao, Jun-Min; Sun, Xiu-Qian; Jiang, Wen-Chao; Wei, Yun-Mei; Guo, Jin-Song; Liu, Yuan-Yuan; Zhang, Ke

    2016-06-01

    We investigated the occurrence of cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), Znic (Zn), iron (Fe), manganese (Mn), and magnesium (Mg) in sediments, as well as in related soils and aquatic plants in the Liangtan River, a typical secondary anabranch of the Yangtze River in the Three Gorges Reservoir Region (TGRR) of China. We found that sediments accumulated more metals than soils and aquatic plants. Concentrations of the nine metals in sediments and soils followed the same sequence, while their concentrations in aquatic plants followed a different sequence. Potential adverse effects of contaminated sediments on benthic fauna were evaluated, and the results showed that the toxic effect on benthic organisms followed the sequence Zn > Ni > Cr > Cu > Cd > Pb. The potential ecological risk index analysis indicated that Cd in sediments had considerable ecological risk, whereas Cr, Cu, Zn, Ni, and Pb had low ecological risk. The potential ecological risk index (RI) of the heavy metals in sediments of the Liangtan River was 174.9, indicating moderate ecological risk. The transfer factor trend of metals for aquatic plants showed that Cd and Ni had the most and least accumulation, respectively. For Cu, Cd, Mg, Pb, and Cr, a significant positive correlation of the metal concentrations was observed between sediments and soils, but no correlations (excluding Cr) were detected between sediments and aquatic plants. Our study indicated that anthropogenic input may be the primary source of metal contamination in the Liangtan River, and that Zn and Cd pollution in the Liangtan River should be further explored. PMID:27055891

  11. Soil erosion and sediment fluxes analysis: a watershed study of the Ni Reservoir, Spotsylvania County, VA, USA.

    PubMed

    Pope, Ian C; Odhiambo, Ben K

    2014-03-01

    Anthropogenic forces that alter the physical landscape are known to cause significant soil erosion, which has negative impact on surface water bodies, such as rivers, lakes/reservoirs, and coastal zones, and thus sediment control has become one of the central aspects of catchment management planning. The revised universal soil loss equation empirical model, erosion pins, and isotopic sediment core analyses were used to evaluate watershed erosion, stream bank erosion, and reservoir sediment accumulation rates for Ni Reservoir, in central Virginia. Land-use and land cover seems to be dominant control in watershed soil erosion, with barren land and human-disturbed areas contributing the most sediment, and forest and herbaceous areas contributing the least. Results show a 7 % increase in human development from 2001 (14 %) to 2009 (21.6 %), corresponding to an increase in soil loss of 0.82 Mg ha(-1) year(-1) in the same time period. (210)Pb-based sediment accumulation rates at three locations in Ni Reservoir were 1.020, 0.364, and 0.543 g cm(-2) year(-1) respectively, indicating that sediment accumulation and distribution in the reservoir is influenced by reservoir configuration and significant contributions from bedload. All three locations indicate an increase in modern sediment accumulation rates. Erosion pin results show variability in stream bank erosion with values ranging from 4.7 to 11.3 cm year(-1). These results indicate that urban growth and the decline in vegetative cover has increased sediment fluxes from the watershed and poses a significant threat to the long-term sustainability of the Ni Reservoir as urbanization continues to increase.

  12. U-Th and 10Be constraints on sediment recycling in proglacial settings, Lago Buenos Aires, Patagonia

    NASA Astrophysics Data System (ADS)

    Cogez, Antoine; Herman, Frédéric; Pelt, Eric; Norton, Kevin; Darvill, Christopher; Christl, Marcus; Morvan, Gilles; Reuschlé, Thierry; Chabaux, François

    2016-04-01

    The sedimentary cycle includes the formation by erosion of rocks, transport and deposition. While erosion and deposition can be documented, the history of sediments between the time it is extracted from the rocks and ultimately deposited into basins remains a major challenge. However, the mechanism of transfer and alteration of the sediments during transport plays a key role in the evolution of basins, feedbacks between erosion and climate, and glacial-interglacial variability of sediment transport and weathering. This is particularly true in proglacial settings because large overdeepenings, in particular, are potential sediment traps for which the efficiency at evacuating those sediments is largely unknown. The Lago Buenos Aires moraines in Patagonia are particularly interesting because they are imbricated from the older in the outer part to the younger in the inner part of the system. We sampled fine grained sediments from these moraines and measured U-Th isotopes in the 4-50 μm silicate fraction. Deposition ages were refined using 10Be exposure ages. We show first that the comminution ages model can be improved by measuring also Th isotopes, from which weathering rates can be deduced. Moreover we show from our data that there is a time lag of 300 kyr on average between erosion and deposition in the moraine. This could be attributed to the long residence time of sediments in the lake overdeepening. This conclusion raises perspectives about the transport times and dynamic of the sediments during a whole sedimentary cycle, and the subsequent effect on weathering. This conclusion could also contradict some assumptions commonly made for our erosion rates/sediment fluxes reconstructions based on river sediments analysis, in recently deglaciated catchments.

  13. Subtask 1.17 - Subcritical Water Extraction of Mercury From Soils and Sediments

    SciTech Connect

    Steven B. Hawthorne

    1997-08-01

    The U.S. Environmental Protection Agency (EPA) "National Sediment Quality Survey" lists the top pollutants responsible for toxicity in watersheds as 1) PCBS (polychlorinated biphenyls), 2) mercury, and 3) other organics such as PAHs polycyclic aromatic hydrocarbons) and pesticides. In addition, these same pollutants are major contributors to chemical pollution on U.S. Department of Energy (DOE) and other contaminated sites (e.g., industrial sites and harbors). An ideal remediation method would allow cost-effective removal of both organic and mercury contamination using a single process. The Energy & Environmental Research Center (EERC) has demonstrated that controlling the temperature (and to a lesser extent, the pressure) of water can dramatically change its ability to extract organics and inorganic from matrices ranging from soils and sediments to waste sludges and coal. The dielectric constant of water can be changed from ca. 80 (a very polar solvent) to <5 (similar to a nonpolar organic solvent) by controlling the temperature (from ca. ambient to ca. 400oC) and pressure (from ea. 5 to 350 bar). The EERC has shown that hazardous organic pollutants such as pesticides, PAHs, and PCBS can be completely removed from soils, sludges, and sediments at temperatures (250"C) and pressures ( c 50 atrn) that are much milder than typically used for supercritical water processes (temperature > 374oC, pressure >221 atm). In addition, the process has been demonstrated to be particularly effective for samples containing very high levels of contaminants (e.g., parts per thousand). The EERC has also demonstrated that mercury can be extracted using supercritical water at much harsher conditions (400"C, and >300 atm). However, the removal of mercury from contaminated solids at the lower temperature and pressure conditions (e. g., 250"C, 50 atm) has not been investigated. If successful, this project will provide the basis for using hot/liquid water to extract both organic

  14. Central Colorado Assessment Project (CCAP)-Geochemical data for rock, sediment, soil, and concentrate sample media

    USGS Publications Warehouse

    Granitto, Matthew; DeWitt, Ed H.; Klein, Terry L.

    2010-01-01

    This database was initiated, designed, and populated to collect and integrate geochemical data from central Colorado in order to facilitate geologic mapping, petrologic studies, mineral resource assessment, definition of geochemical baseline values and statistics, environmental impact assessment, and medical geology. The Microsoft Access database serves as a geochemical data warehouse in support of the Central Colorado Assessment Project (CCAP) and contains data tables describing historical and new quantitative and qualitative geochemical analyses determined by 70 analytical laboratory and field methods for 47,478 rock, sediment, soil, and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed either in the analytical laboratories of the USGS or by contract with commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects. In addition, geochemical data from 7,470 sediment and soil samples collected and analyzed under the Atomic Energy Commission National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program (henceforth called NURE) have been included in this database. In addition to data from 2,377 samples collected and analyzed under CCAP, this dataset includes archived geochemical data originally entered into the in-house Rock Analysis Storage System (RASS) database (used by the USGS from the mid-1960s through the late 1980s) and the in-house PLUTO database (used by the USGS from the mid-1970s through the mid-1990s). All of these data are maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB and from the NURE database were used to generate most of this dataset. In addition, USGS data that have been excluded previously from the NGDB because the data predate earliest USGS geochemical databases, or were once excluded for programmatic reasons

  15. Improved quantification of pyrogenic carbon in soils and sediments by a HPLC-DAD method

    NASA Astrophysics Data System (ADS)

    Wiedemeier, D. B.; Hilf, M. D.; Smittenberg, R. H.; Schmidt, M. W. I.

    2012-04-01

    Fire-derived (pyrogenic) carbon (PyC) is produced by the incomplete combustion of biomass, for example during wildfires. It can persist in the environment for a long time due to its relative resistance against biological and chemical breakdown. Its accurate quantification in soils and sediments is of great interest because the slow turn-over of PyC has implications for the global carbon cycle and carbon budget calculations. Moreover, PyC in pedological and sedimentological records can be used to reconstruct wildfire history or to investigate historical periods like the industrialization. A whole suite of PyC quantification methods exists because PyC is not a defined chemical structure but rather a continuum of thermally altered biomass. The benzene polycarboxylic acids (BPCA) analysis is a molecular marker method that was shown to give conservative estimates of PyC quantity in soils. In addition, it yields qualitative information about the degree of aromaticity and condensation of PyC. The commonly used BPCA method consists in digesting samples with nitric acid that breaks down the PyC into a suite of BPCAs, which are cleaned, derivatized and finally analyzed by gas chromatography-flame ionization detection (GC-FID). Here, we present a modified BPCA method for soils and sediments that uses a high performance liquid chromatography system coupled to diode array detection (HPLC-DAD). We demonstrate that this method greatly enhances the reproducibility of PyC quantification in soil and sediment samples while significantly reducing analysis time. Moreover, much less sample material is needed for precise PyC quantification and we show that the HPLC-DAD method yields consistently higher PyC contents than the GC-FID method. Additionally, the modified method also facilitates δ13C and 14C measurements of the PyC fraction in these complex matrix samples. The isotopic information further improves the assessment of PyC budgets in the environment and the reconstruction of past

  16. Seasonal distributions of fungicides in soils and sediments of a small river basin partially devoted to vineyards.

    PubMed

    Bermúdez-Couso, A; Arias-Estévez, M; Nóvoa-Muñoz, J C; López-Periago, E; Soto-González, B; Simal-Gándara, J

    2007-11-01

    The acid soils of Ourense province riverland (Galicia, NW Spain) produce about 50,000 tons of grapes for winemaking. As part of ongoing investigations into fungicide transport in Ourense vineyard soils, the occurrence of several fungicides in such soils was investigated. Soil samples were collected from the inter-row topsoil of a vineyard adjacent to the River Alongos, approximately 15 km SW of the main city of Ourense. The vines were grown in sandy loam with moderate organic carbon (OC) content (1-2%). Fungicide residues were measured in vineyard soils and river sediments by solid-liquid extraction followed by gas chromatography with mass spectrometric detection (GC-MSD). Procymidone and cyprodinil occurred at higher levels in river sediments than in the case of fludioxonil, metalaxyl and penconazole. The highest concentrations of procymidone in sediments were still low (29-57 microg/kg or ppb) suggesting that no accumulation of these compounds occur. All of them were found at higher concentrations in soil; maxima concentrations were about 1000 microg/kg for procymidone and metalaxyl, and about 400 microg/kg for cyprodinil, fludioxonil and penconazole. Folpet was never detected (detection limit lower than 2 microg/kg) in soil and sediments, suggesting that this fungicide was unstable in such samples. The frequency of fungicide detections in soils can be related to their applications in vineyards and the effect of washing off through vineyard canopy by rainfalls. The results found suggest that the vineyard soils of this region are unlikely to be prone to transport of fungicides, and therefore water supplies in this area are unlikely to be at any significant risk of contamination through viticultural use of these compounds.

  17. Seasonal distributions of fungicides in soils and sediments of a small river basin partially devoted to vineyards.

    PubMed

    Bermúdez-Couso, A; Arias-Estévez, M; Nóvoa-Muñoz, J C; López-Periago, E; Soto-González, B; Simal-Gándara, J

    2007-11-01

    The acid soils of Ourense province riverland (Galicia, NW Spain) produce about 50,000 tons of grapes for winemaking. As part of ongoing investigations into fungicide transport in Ourense vineyard soils, the occurrence of several fungicides in such soils was investigated. Soil samples were collected from the inter-row topsoil of a vineyard adjacent to the River Alongos, approximately 15 km SW of the main city of Ourense. The vines were grown in sandy loam with moderate organic carbon (OC) content (1-2%). Fungicide residues were measured in vineyard soils and river sediments by solid-liquid extraction followed by gas chromatography with mass spectrometric detection (GC-MSD). Procymidone and cyprodinil occurred at higher levels in river sediments than in the case of fludioxonil, metalaxyl and penconazole. The highest concentrations of procymidone in sediments were still low (29-57 microg/kg or ppb) suggesting that no accumulation of these compounds occur. All of them were found at higher concentrations in soil; maxima concentrations were about 1000 microg/kg for procymidone and metalaxyl, and about 400 microg/kg for cyprodinil, fludioxonil and penconazole. Folpet was never detected (detection limit lower than 2 microg/kg) in soil and sediments, suggesting that this fungicide was unstable in such samples. The frequency of fungicide detections in soils can be related to their applications in vineyards and the effect of washing off through vineyard canopy by rainfalls. The results found suggest that the vineyard soils of this region are unlikely to be prone to transport of fungicides, and therefore water supplies in this area are unlikely to be at any significant risk of contamination through viticultural use of these compounds. PMID:17624393

  18. Historical changes in air temperature are evident in temperature fluxes measured in the sub-soil.

    NASA Astrophysics Data System (ADS)

    Fraser, Fiona; McCormick, Benjamin; Hallett, Paul; Wookey, Philip; Hopkins, David

    2013-04-01

    Warming trends in soil temperature have implications for a plethora of soil processes, including exacerbated climate change through the net release of greenhouse gases. Whereas long-term datasets of air temperature changes are abundant, a search of scientific literature reveals a lack of information on soil temperature changes and their specific consequences. We analysed five long-term data series collected in the UK (Dundee and Armagh) and Canada (Charlottetown, Ottawa and Swift Current). They show that the temperatures of soils at 5 - 20 cm depth, and sub-soils at 30 - 150 cm depth, increased in line with air temperature changes over the period 1958 - 2003. Differences were found, however, between soil and air temperatures when data were sub-divided into seasons. In spring, soil temperature warming ranged from 0.19°C at 30 cm in Armagh to 4.30°C at 50 cm in Charlottetown. In summer, however, the difference was smaller and ranged from 0.21°C at 10 cm in Ottawa to 3.70°C at 50 cm in Charlottetown. Winter temperatures were warmer in soil and ranged from 0.45°C at 5 cm in Charlottetown to 3.76°C at 150 cm in Charlottetown. There were significant trends in changes to soil temperature over time, whereas air temperature trends tended only to be significant in winter (changes range from 1.27°C in Armagh to 3.35°C in Swift Current). Differences in the seasonal warming patterns between air and soil temperatures have potential implications for the parameterization of models of biogeochemical cycling.

  19. CO2 CH4 flux Air temperature Soil temperature and Soil moisture, Barrow, Alaska 2013 ver. 1

    SciTech Connect

    Margaret Torn

    2015-01-14

    This dataset consists of field measurements of CO2 and CH4 flux, as well as soil properties made during 2013 in Areas A-D of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska. Included are i) measurements of CO2 and CH4 flux made from June to September (ii) Calculation of corresponding Gross Primary Productivity (GPP) and CH4 exchange (transparent minus opaque) between atmosphere and the ecosystem (ii) Measurements of Los Gatos Research (LGR) chamber air temperature made from June to September (ii) measurements of surface layer depth, type of surface layer, soil temperature and soil moisture from June to September.

  20. Soil erosion and sediment control laws. A review of state laws and their natural resource data requirements

    NASA Technical Reports Server (NTRS)

    Klein, S. B.

    1980-01-01

    Twenty states, the District of Columbia, and the Virgin Islands enacted erosion and sediment control legislation during the past decade to provide for the implementation or the strengthening of statewide erosion and sediment control plans for rural and/or urban lands. That legislation and the state programs developed to implement these laws are quoted and reviewed. The natural resource data requirements of each program are also extracted. The legislation includes amendments to conservation district laws, water quality laws, and erosion and sediment control laws. Laws which provides for legislative review of administrative regulations and LANDSAT applications and/or information systems that were involved in implementing or gathering data for a specific soil erosion and sediment control program are summarized as well as principal concerns affecting erosion and sediment control laws.

  1. A theoretical assessment of microplastic transport in river catchments and their retention by soils and river sediments.

    PubMed

    Nizzetto, Luca; Bussi, Gianbattista; Futter, Martyn N; Butterfield, Dan; Whitehead, Paul G

    2016-08-10

    The presence of microplastics (MPs) in the environment is a problem of growing concern. While research has focused on MP occurrence and impacts in the marine environment, very little is known about their release on land, storage in soils and sediments and transport by run-off and rivers. This study describes a first theoretical assessment of these processes. A mathematical model of catchment hydrology, soil erosion and sediment budgets was upgraded to enable description of MP fate. The Thames River in the UK was used as a case study. A general lack of data on MP emissions to soils and rivers and the mass of MPs in agricultural soils, limits the present work to serve as a purely theoretical, nevertheless rigorous, assessment that can be used to guide future monitoring and impact evaluations. The fundamental assumption on which modelling is based is that the same physical controls on soil erosion and natural sediment transport (for which model calibration and validation are possible), also control MP transport and storage. Depending on sub-catchment soil characteristics and precipitation patterns, approximately 16-38% of the heavier-than-water MPs hypothetically added to soils (e.g. through routine applications of sewage sludge) are predicted to be stored locally. In the stream, MPs < 0.2 mm are generally not retained, regardless of their density. Larger MPs with densities marginally higher than water can instead be retained in the sediment. It is, however, anticipated that high flow periods can remobilize this pool. Sediments of river sections experiencing low stream power are likely hotspots for deposition of MPs. Exposure and impact assessments should prioritize these environments.

  2. A theoretical assessment of microplastic transport in river catchments and their retention by soils and river sediments.

    PubMed

    Nizzetto, Luca; Bussi, Gianbattista; Futter, Martyn N; Butterfield, Dan; Whitehead, Paul G

    2016-08-10

    The presence of microplastics (MPs) in the environment is a problem of growing concern. While research has focused on MP occurrence and impacts in the marine environment, very little is known about their release on land, storage in soils and sediments and transport by run-off and rivers. This study describes a first theoretical assessment of these processes. A mathematical model of catchment hydrology, soil erosion and sediment budgets was upgraded to enable description of MP fate. The Thames River in the UK was used as a case study. A general lack of data on MP emissions to soils and rivers and the mass of MPs in agricultural soils, limits the present work to serve as a purely theoretical, nevertheless rigorous, assessment that can be used to guide future monitoring and impact evaluations. The fundamental assumption on which modelling is based is that the same physical controls on soil erosion and natural sediment transport (for which model calibration and validation are possible), also control MP transport and storage. Depending on sub-catchment soil characteristics and precipitation patterns, approximately 16-38% of the heavier-than-water MPs hypothetically added to soils (e.g. through routine applications of sewage sludge) are predicted to be stored locally. In the stream, MPs < 0.2 mm are generally not retained, regardless of their density. Larger MPs with densities marginally higher than water can instead be retained in the sediment. It is, however, anticipated that high flow periods can remobilize this pool. Sediments of river sections experiencing low stream power are likely hotspots for deposition of MPs. Exposure and impact assessments should prioritize these environments. PMID:27255969

  3. XANES spectroscopy as a tool to trace phosphorus transformation during soil genesis and mountain ecosystem development from lake sediments

    NASA Astrophysics Data System (ADS)

    Giguet-Covex, C.; Poulenard, J.; Chalmin, E.; Arnaud, F.; Rivard, C.; Jenny, J.-P.; Dorioz, J.-M.

    2013-10-01

    The aim of this study is to investigate phosphorus (P) species modifications triggered by soil genesis and mountain ecosystem development after glacial retreat using a lake sediment archive (Lake Anterne, North French Alps). Five lake sediment samples, representative of different stages of soil and ecosystem development, were selected for P speciation analyses. Furthermore, a sequence of current soils from the catchment was analyzed to better constrain our interpretations of the lacustrine archive. Synchrotron techniques (X-ray Fluorescence (XRF) mapping and P K-edge X-ray absorption near edge structure (XANES) spectroscopy) were applied to lake sediments, soils, and standards (mineral and organic) to distinguish between different P species. The results show that soil development during the first millennia of the Holocene triggered increased P species diversity. At the onset of the Holocene, P was present as apatite when rocks and leptosols dominated the catchment. Pedogenic processes then led to apatite dissolution and the formation of large amounts of P on metal/clay-organic complexes. P geochemistry during the main step of soil genesis (early leptosols dominated by apatite, low weathered cambisols with P mainly adsorbed on iron oxides, highly weathered podzols with large amounts of P on Al/Fe/clay organic complexes) is thus clearly recorded in lake sediments. P K-edge XANES spectroscopy is particularly relevant as qualitative method to study P species in soils and lake sediments at high spatial resolution. Such resolution is needed to reveal the diversity of small P particles and like this better characterize the P cycle and improve our understanding of ecosystem evolution.

  4. Membrane-micelle model for humus in soils and sediments and its relation to humification

    USGS Publications Warehouse

    Wershaw, Robert L.

    1994-01-01

    Humification, the process whereby biomass consisting of dead plant and animal remains is converted into soil organic matter (humus), is one of the basic processes of the carbon cycle. The organic compounds that make up plant and animal tissue are thermodynamically unstable in the oxidizing atmosphere at the surface of the Earth. After the organisms in which they are incorporated die, the compounds are converted back to carbon dioxide and water by degradation reactions catalyzed by enzymes secreted by micro-organisms. However, not all the organic compounds in the dead biomass are immediately converted; some of the material is only partially oxidized. The residue left after partial oxidative degradation of the dead biomass is the source of the organic compounds that accumulate in soils and sediments as humus. Previously, humification was thought to involve a conversion of degradation products by a series of polymerization reactions into new types of polymeric species that are different from the precursor molecular species in the original biomass. However, it is proposed here that the depolymerization and oxidation reactions that take place during the enzymatic degradation of biopolymers produce amphiphiles--molecules that have a polar (hydrophilic) part and a nonpolar (hydrophobic) part. These amphiphiles that result from the partial oxidative degradation of dead biomass assemble spontaneously into ordered aggregates in which the hydrophobic parts of the molecules form the interiors and the hydrophilic parts of the molecules make up the exterior surfaces of the aggregates. These ordered aggregates constitute the humus in soils and sediments. Humus ordered aggregates most likely exist as bilayer membranes coating mineral grains and as micelles in solution.

  5. Evaluating the importance of surface soil contributions to reservoir sediment in alpine environments: a combined modelling and fingerprinting approach in the Posets-Maladeta Natural Park

    NASA Astrophysics Data System (ADS)

    Palazón, L.; Gaspar, L.; Latorre, B.; Blake, W. H.; Navas, A.

    2014-09-01

    Soil in alpine environments plays a key role in the development of ecosystem services and in order to maintain and preserve this important resource, information is required on processes that lead to soil erosion. Similar to other mountain alpine environments, the Benasque catchment is characterised by temperatures below freezing that can last from November to April, intense rainfall events, typically in spring and autumn, and rugged topography which makes assessment of erosion challenging. Indirect approaches to soil erosion assessment, such as combined model approaches, offer an opportunity to evaluate soil erosion in such areas. In this study (i) the SWAT (Soil and Water Assessment Tool) hydrological and erosion model and (ii) sediment fingerprinting procedures were used in parallel to assess the viability of a combined modelling and tracing approach to evaluate soil erosion processes in the area of the Posets-Maladeta Natural Park (central Spanish Pyrenees). Soil erosion rates and sediment contribution of potential sediment sources defined by soil type (Kastanozems/Phaeozems; Fluvisols and Cambisols) were assessed. The SWAT model suggested that, with the highest specific sediment yields, Cambisols are the main source of sediment in the Benasque catchment and Phaeozems and Fluvisols were identified as the lowest sediment contributors. Spring and winter model runs gave the highest and lowest specific sediment yield, respectively. In contrast, sediment fingerprinting analysis identified Fluvisols, which dominate the riparian zone, as the main sediment source at the time of sampling. This indicates the importance of connectivity as well as potential differences in the source dynamic of material in storage versus that transported efficiently from the system at times of high flow. The combined approach enabled us to better understand soil erosion processes in the Benasque alpine catchment, wherein SWAT identified areas of potential high sediment yield in large flood

  6. CONTROL OF AROMATIC WASTE AIR STREAMS BY SOIL BIOREACTORS

    EPA Science Inventory

    Three soils were examined for the ability to degrade hydrocarbon vapors of benzene, toluene, ethylbenzene, and o-xylene (BTEX). Each of these compounds are major aromatic constituents of gasolines. The soils examined were Rubicon Sand from Traverse City, Michigan, Durant Loam fro...

  7. Removal of volatile and semivolatile organic contamination from soil by air and steam flushing.

    PubMed

    Sleep, B E; McClure, P D

    2001-07-01

    A soil core, obtained from a contaminated field site, contaminated with a mixture of volatile and semivolatile organic compounds (VOC and SVOC) was subjected to air and steam flushing. Removal rates of volatile and semivolatile organic compounds were monitored during flushing. Air flushing removed a significant portion of the VOC present in the soil, but a significant decline in removal rate occurred due to decreasing VOC concentrations in the soil gas phase. Application of steam flushing after air flushing produced a significant increase in contaminant removal rate for the first 4 to 5 pore volumes of steam condensate. Subsequently, contaminant concentrations decreased slowly with additional pore volumes of steam flushing. The passage of a steam volume corresponding to 11 pore volumes of steam condensate reduced the total VOC concentration in the soil gas (at 20 degrees C) by a factor of 20 to 0.07 mg/l. The corresponding total SVOC concentration in the condensate declined from 11 to 3 mg/l. Declines in contaminant removal rates during both air and steam flushing indicated rate-limited removal consistent with the persistence of a residual organic phase, rate-limited desorption, or channeling. Pressure gradients were much higher for steam flushing than for air flushing. The magnitude of the pressure gradients encountered during steam flushing for this soil indicates that, in addition to rate-limited contaminant removal, the soil permeability (2.1 x 10(-9) cm2) would be a limiting factor in the effectiveness of steam flushing. PMID:11475159

  8. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation

    SciTech Connect

    Garbesi, K.; Sextro, R.G.; Robinson, Arthur L.; Wooley, J.D.; Owens, J.A.; Nazaroff, W.W.

    1995-11-01

    This work investigates the dependence soil air-permeability on sampling scale in near-surface unsaturated soils. A new dual-probe dynamic pressure technique was developed to measure permeability in situ over different length scales and different spatial orientations in the soil. Soils at three sites were studied using the new technique. Each soil was found to have higher horizontal than vertical permeability. Significant scale dependence of permeability was also observed at each site. Permeability increased by a factor of 20 as sampling scale increased from 0.1 to 2 m in a sand soil vegetated with dry grass, and by a factor of 15 as sampling scale increased from 0.1 to 3.5 m in a sandy loam with mature Coast Live Oak trees (Quercus agrifolia). The results indicate that standard methods of permeability assessment can grossly underestimate advective transport of gas-phase contaminants through soils.

  9. Standard operating procedures for collection of soil and sediment samples for the Sediment-bound Contaminant Resiliency and Response (SCoRR) strategy pilot study

    USGS Publications Warehouse

    Fisher, Shawn C.; Reilly, Timothy J.; Jones, Daniel K.; Benzel, William M.; Griffin, Dale W.; Loftin, Keith A.; Iwanowicz, Luke R.; Cohl, Jonathan A.

    2015-12-17

    An understanding of the effects on human and ecological health brought by major coastal storms or flooding events is typically limited because of a lack of regionally consistent baseline and trends data in locations proximal to potential contaminant sources and mitigation activities, sensitive ecosystems, and recreational facilities where exposures are probable. In an attempt to close this gap, the U.S. Geological Survey (USGS) has implemented the Sediment-bound Contaminant Resiliency and Response (SCoRR) strategy pilot study to collect regional sediment-quality data prior to and in response to future coastal storms. The standard operating procedure (SOP) detailed in this document serves as the sample-collection protocol for the SCoRR strategy by providing step-by-step instructions for site preparation, sample collection and processing, and shipping of soil and surficial sediment (for example, bed sediment, marsh sediment, or beach material). The objectives of the SCoRR strategy pilot study are (1) to create a baseline of soil-, sand-, marsh sediment-, and bed-sediment-quality data from sites located in the coastal counties from Maine to Virginia based on their potential risk of being contaminated in the event of a major coastal storm or flooding (defined as Resiliency mode); and (2) respond to major coastal storms and flooding by reoccupying select baseline sites and sampling within days of the event (defined as Response mode). For both modes, samples are collected in a consistent manner to minimize bias and maximize quality control by ensuring that all sampling personnel across the region collect, document, and process soil and sediment samples following the procedures outlined in this SOP. Samples are analyzed using four USGS-developed screening methods—inorganic geochemistry, organic geochemistry, pathogens, and biological assays—which are also outlined in this SOP. Because the SCoRR strategy employs a multi-metric approach for sample analyses, this

  10. Diffuse-reflectance mid-infrared spectrocopy reveals chemical differences in soil organic matter carried in different size wind eroded sediments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil organic matter (SOM) influences water holding capacity, aggregation, and diversity. Little information is available regarding the C functional groups carried in wind eroded sediments away from the source soil. Mid-infrared (MidIR) spectra was used on wind tunnel-blown sediments eroded from a lo...

  11. Bisphenol A, nonylphenols, benzophenones, and benzotriazoles in soils, groundwater, surface water, sediments, and food: a review.

    PubMed

    Careghini, Alessando; Mastorgio, Andrea Filippo; Saponaro, Sabrina; Sezenna, Elena

    2015-04-01

    Contaminants of emerging concern (CECs) are not commonly monitored in the environment, but they can enter the environment from a variety of sources. The most worrying consequence of their wide use and environmental diffusion is the increase in the possible exposure pathways for humans. Moreover, knowledge of their behavior in the environment, toxicity, and biological effects is limited or not available for most CECs. The aim of this work is to edit the state of the art on few selected CECs having the potential to enter the soil and aquatic systems and cause adverse effects in humans, wildlife, and the environment: bisphenol A (BPA), nonylphenol (NP), benzophenones (BPs), and benzotriazole (BT). Some reviews are already available on BPA and NP, reporting about their behavior in surface water and sediments, but scarce and scattered information is available about their presence in soil and groundwater. Only a few studies are available about BPs and BT in the environment, in particular in soil and groundwater. This work summarizes the information available in the literature about the incidence and behavior of these compounds in the different environmental matrices and food. In particular, the review focuses on the physical-chemical properties, the environmental fate, the major degradation byproducts, and the environmental evidence of the selected CECs.

  12. Analysis of the NASA AirMOSS Root Zone Soil Water and Soil Temperature from Three North American Ecosystems

    NASA Astrophysics Data System (ADS)

    Hagimoto, Y.; Cuenca, R. H.

    2015-12-01

    Root zone soil water and temperature are controlling factors for soil organic matter accumulation and decomposition which contribute significantly to the CO2 flux of different ecosystems. An in-situ soil observation protocol developed at Oregon State University has been deployed to observe soil water and temperature dynamics in seven ecological research sites in North America as part of the NASA AirMOSS project. Three instrumented profiles defining a transect of less than 200 m are installed at each site. All three profiles collect data for in-situ water and temperature dynamics employing seven soil water and temperature sensors installed at seven depth levels and one infrared surface temperature sensor monitoring the top of the profile. In addition, two soil heat flux plates and associated thermocouples are installed at one of three profiles at each site. At each profile, a small 80 cm deep access hole is typically made, and all below ground sensors are installed into undisturbed soil on the side of the hole. The hole is carefully refilled and compacted so that root zone soil water and temperature dynamics can be observed with minimum site disturbance. This study focuses on the data collected from three sites: a) Tonzi Ranch, CA; b) Metolius, OR and c) BERMS Old Jack Pine Site, Saskatchewan, Canada. The study describes the significantly different seasonal root zone water and temperature dynamics under the various physical and biological conditions at each site. In addition, this study compares the soil heat flux values estimated by the standard installation using the heat flux plates and thermocouples installed near the surface with those estimated by resolving the soil heat storage based on the soil water and temperature data collected over the total soil profile.

  13. Enrichment of Arsenic in Surface Water, Stream Sediments and Soils in Tibet

    PubMed Central

    Li, Shehong; Wang, Mingguo; Yang, Qiang; Wang, Hui; Zhu, Jianming; Zheng, Baoshan; Zheng, Yan

    2013-01-01

    Groundwater in sedimentary deposits in China, Southern, and Southeast Asia down gradient from the Tibetan plateau contain elevated As concentrations on a regional scale. To ascertain the possibility of source region As enrichment, samples of water (n=86), stream sediment (n=77) and soil (n=73) were collected from the Singe Tsangpo (upstream of the Indus River), Yarlung Tsangpo (upstream of the Brahmaputra River) and other drainage basins in Tibet in June of 2008. The average arsenic concentration in stream waters, sediments and soils was 58±70 μg/L (n=39, range 2-252 μg/L), 42±40 mg/kg (n=37, range 12-227 mg/kg), and 44±27mg/kg (n=28, range 12-84 mg/kg) respectively for the Singe Tsangpo and was 11±17 μg/L (n=30, range 2-83 μg/L), 28±11 mg/kg (n=28, range 2-61 mg/kg), and 30±34 mg/kg (n=21, range 6-173 mg/kg) respectively for the Yarlung Tsangpo. A dug well contained 195 μg/L of As. In addition to elevated As levels in surface and shallow groundwater of Tibet, hot spring and alkaline salt lake waters displayed very high As levels, reaching a maximum value of 5,985 μg/L and 10,626 μg/L As, respectively. The positive correlation between [As] and [Na]+[K] in stream waters indicates that these surface water arsenic enrichments are linked to the hot springs and/or salt lakes. Further, 24% of As in stream sediment is reductively leachable, with bulk As displaying a positive correlation with stream water As, suggesting sorption from stream water. In contrast, the fraction of reductively leachable As is negligible for soils and several rock samples, suggesting that As in them are associated with unweathered minerals. Whether the pronounced As anomaly found in Tibet affects the sedimentary As content in deltas downstream or not requires further study. PMID:24367140

  14. Enrichment of Arsenic in Surface Water, Stream Sediments and Soils in Tibet.

    PubMed

    Li, Shehong; Wang, Mingguo; Yang, Qiang; Wang, Hui; Zhu, Jianming; Zheng, Baoshan; Zheng, Yan

    2013-12-01

    Groundwater in sedimentary deposits in China, Southern, and Southeast Asia down gradient from the Tibetan plateau contain elevated As concentrations on a regional scale. To ascertain the possibility of source region As enrichment, samples of water (n=86), stream sediment (n=77) and soil (n=73) were collected from the Singe Tsangpo (upstream of the Indus River), Yarlung Tsangpo (upstream of the Brahmaputra River) and other drainage basins in Tibet in June of 2008. The average arsenic concentration in stream waters, sediments and soils was 58±70 μg/L (n=39, range 2-252 μg/L), 42±40 mg/kg (n=37, range 12-227 mg/kg), and 44±27mg/kg (n=28, range 12-84 mg/kg) respectively for the Singe Tsangpo and was 11±17 μg/L (n=30, range 2-83 μg/L), 28±11 mg/kg (n=28, range 2-61 mg/kg), and 30±34 mg/kg (n=21, range 6-173 mg/kg) respectively for the Yarlung Tsangpo. A dug well contained 195 μg/L of As. In addition to elevated As levels in surface and shallow groundwater of Tibet, hot spring and alkaline salt lake waters displayed very high As levels, reaching a maximum value of 5,985 μg/L and 10,626 μg/L As, respectively. The positive correlation between [As] and [Na]+[K] in stream waters indicates that these surface water arsenic enrichments are linked to the hot springs and/or salt lakes. Further, 24% of As in stream sediment is reductively leachable, with bulk As displaying a positive correlation with stream water As, suggesting sorption from stream water. In contrast, the fraction of reductively leachable As is negligible for soils and several rock samples, suggesting that As in them are associated with unweathered minerals. Whether the pronounced As anomaly found in Tibet affects the sedimentary As content in deltas downstream or not requires further study.

  15. Study of soil aggregate breakdown dynamics under low dispersive ultrasonic energies with sedimentation and X-ray attenuation**

    PubMed Central

    Schomakers, Jasmin; Zehetner, Franz; Mentler, Axel; Ottner, Franz; Mayer, Herwig

    2016-01-01

    It has been increasingly recognized that soil organic matter stabilization is strongly controlled by physical binding within soil aggregates. It is therefore essential to measure soil aggregate stability reliably over a wide range of disruptive energies and different aggregate sizes. To this end, we tested high-accuracy ultrasonic dispersion in combination with subsequent sedimentation and X-ray attenuation. Three arable topsoils (notillage) from Central Europe were subjected to ultrasound at four different specific energy levels: 0.5, 6.7, 100 and 500 J cm−3, and the resulting suspensions were analyzed for aggregate size distribution by wet sieving (2 000-63 μm) and sedimentation/X-ray attenuation (63-2 μm). The combination of wet sieving and sedimentation technique allowed for a continuous analysis, at high resolution, of soil aggregate breakdown dynamics after defined energy inputs. Our results show that aggregate size distribution strongly varied with sonication energy input and soil type. The strongest effects were observed in the range of low specific energies (< 10 J cm−3), which previous studies have largely neglected. This shows that low ultrasonic energies are required to capture the full range of aggregate stability and release of soil organic matter upon aggregate breakdown. PMID:27099408

  16. Budgets of soil erosion and deposition for sediments and sedimentary organic carbon across the conterminous United States

    USGS Publications Warehouse

    Smith, S.V.; Renwick, W.H.; Buddemeier, R.W.; Crossland, C.J.

    2001-01-01

    The fate of soil organic matter during erosion and sedimentation has been difficult to assess because of the large size and complex turnover characteristics of the soil carbon reservoir. It has been assumed that most of the carbon released during erosion is lost to oxidation. Budgets of bulk soil and soil organic carbon erosion and deposition suggest that the primary fates of eroded soil carbon across the conterminous United States are trapping in impoundments and other redeposition. The total amount of soil carbon eroded and redeposited across the United States is ???0.04 Gt yr-1. Applying this revision to the U. S. carbon budget by Houghton et al. [1999] raises their net sequestration estimate by 20-47 %. If comparable rates of erosion and redeposition occur globally, net carbon sequestration would be ???1 Gt yr-1.

  17. A review on slurry bioreactors for bioremediation of soils and sediments

    PubMed Central

    Robles-González, Ireri V; Fava, Fabio; Poggi-Varaldo, Héctor M

    2008-01-01

    The aim of this work is to present a critical review on slurry bioreactors (SB) and their application to bioremediation of soils and sediments polluted with recalcitrant and toxic compounds. The scope of the review encompasses the following subjects: (i) process fundamentals of SB and analysis of advantages and disadvantages; (ii) the most recent applications of SB to laboratory scale and commercial scale soil bioremediation, with a focus on pesticides, explosives, polynuclear aromatic hydrocarbons, and chlorinated organic pollutants; (iii) trends on the use of surfactants to improve availability of contaminants and supplementation with degradable carbon sources to enhance cometabolism of pollutants; (iv) recent findings on the utilization of electron acceptors other than oxygen; (v) bioaugmentation and advances made on characterization of microbial communities of SB; (vi) developments on ecotoxicity assays aimed at evaluating bioremediation efficiency of the process. From this review it can be concluded that SB is an effective ad situ and ex situ technology that can be used for bioremediation of problematic sites, such as those characterized by soils with high contents of clay and organic matter, by pollutants that are recalcitrant, toxic, and display hysteretic behavior, or when bioremediation should be accomplished in short times under the pressure and monitoring of environmental agencies and regulators. SB technology allows for the convenient manipulation and control of several environmental parameters that could lead to enhanced and faster treatment of polluted soils: nutrient N, P and organic carbon source (biostimulation), inocula (bioaugmentation), increased availability of pollutants by use of surfactants or inducing biosurfactant production inside the SB, etc. An interesting emerging area is the use of SB with simultaneous electron acceptors, which has demonstrated its usefulness for the bioremediation of soils polluted with hydrocarbons and some

  18. A review on slurry bioreactors for bioremediation of soils and sediments.

    PubMed

    Robles-González, Ireri V; Fava, Fabio; Poggi-Varaldo, Héctor M

    2008-02-29

    The aim of this work is to present a critical review on slurry bioreactors (SB) and their application to bioremediation of soils and sediments polluted with recalcitrant and toxic compounds. The scope of the review encompasses the following subjects: (i) process fundamentals of SB and analysis of advantages and disadvantages; (ii) the most recent applications of SB to laboratory scale and commercial scale soil bioremediation, with a focus on pesticides, explosives, polynuclear aromatic hydrocarbons, and chlorinated organic pollutants; (iii) trends on the use of surfactants to improve availability of contaminants and supplementation with degradable carbon sources to enhance cometabolism of pollutants; (iv) recent findings on the utilization of electron acceptors other than oxygen; (v) bioaugmentation and advances made on characterization of microbial communities of SB; (vi) developments on ecotoxicity assays aimed at evaluating bioremediation efficiency of the process.From this review it can be concluded that SB is an effective ad situ and ex situ technology that can be used for bioremediation of problematic sites, such as those characterized by soils with high contents of clay and organic matter, by pollutants that are recalcitrant, toxic, and display hysteretic behavior, or when bioremediation should be accomplished in short times under the pressure and monitoring of environmental agencies and regulators. SB technology allows for the convenient manipulation and control of several environmental parameters that could lead to enhanced and faster treatment of polluted soils: nutrient N, P and organic carbon source (biostimulation), inocula (bioaugmentation), increased availability of pollutants by use of surfactants or inducing biosurfactant production inside the SB, etc. An interesting emerging area is the use of SB with simultaneous electron acceptors, which has demonstrated its usefulness for the bioremediation of soils polluted with hydrocarbons and some

  19. 210Pb dating of sediments in a heavily contaminated drainage channel to the La Plata estuary in Buenos Aires, Argentina.

    PubMed

    Di Gregorio, D E; Fernández Niello, J O; Huck, H; Somacal, H; Curutchet, G

    2007-01-01

    Concentrations of (210)Pb and (137)Cs in sediment samples collected from two cores at a drainage channel to the La Plata river estuary in Buenos Aires, Argentina, were measured using ultralow-background detection systems. The (210)Pb data were used to determine the rate of sediment accumulation of the sites. These results were correlated with some heavy metal (chromium and lead) concentrations of the samples in an attempt to characterize the historical input of contaminants due to the industrial development, which has taken place in this area over the last century. The (137)Cs measurements demonstrate that cesium dating is not adequate in regions of the southern hemisphere.

  20. Check dam sediments: an important indicator of the effects of environmental changes on soil erosion in the Loess Plateau in China.

    PubMed

    Wang, Yafeng; Chen, Liding; Fu, Bojie; Lü, Yihe

    2014-07-01

    Check dam sediments document the process of soil erosion for a watershed. The main objectives of this research are as follows: first, to determine whether the sediments trapped in check dams can provide useful information about local erosion and the environment, and second, to obtain the extent to which they can be stratigraphically interpreted and correlated to the land use history of an area controlled by check dams. Particle size and the concentration of (137)Cs in sediments are the indicators used to study the effects of environmental changes on soil erosion in the Loess Plateau, China. A total of 216 soil samples were collected from four sediment profile cores at the Yangjuangou watershed check dam constructed in 1955 and fully silted with sediments by 1965. The results indicated that (137)Cs dating and sediment particle size can characterize the sediment deposition process. Silt makes up more than 50 % of the sediment; both the clay and silt sediment fractions decrease gradually in the upstream direction. The sediment profiles are characterized by three depositional layers. These layers suggest changes in the land use. The top layer showed tillage disturbance, with moderate sediments and new soil mixed from 0 to 20 cm. A transition stage from wetlands (characterized by vegetation such as bulrush) to cropland is inferred from sediments at depths of 20-85 cm. Below 85 cm, sedimentary layering is obvious and there is no tillage disturbance. At the downstream site, A0, the average rate of sediment deposition from 1958 to 1963 was approximately 6,125.4 t year(-1) km(-2). Because of their high time resolution, check dam sediments indicate the effects of environmental changes on soil erosion, and they can provide a multiyear record of the soil erosion evolution at the local scale in the middle reaches of the Yellow River.

  1. Suspended sediment export in five intensive agricultural river catchments with contrasting land use and soil drainage characteristics

    NASA Astrophysics Data System (ADS)

    Sherriff, Sophie; Rowan, John; Melland, Alice; Jordan, Phil; Fenton, Owen; hUallacháin, Daire Ó.

    2015-04-01

    Soil erosion and sediment loss from land can have a negative impact on the chemical and ecological quality of freshwater resources. In catchments dominated by agriculture, prediction of soil erosion risk is complex due to the interaction of physical characteristics such as topography, soil erodibility, hydrological connectivity and climate. Robust measurement approaches facilitate the assessment of sediment loss magnitudes in relation to a range of agricultural settings. These approaches improve our understanding of critical sediment transfer periods and inform development of evidence-based and cost-effective management strategies. The aim of this study was to i) assess the efficacy of out-of-channel (ex-situ) suspended sediment measurement approaches, ii) to quantify the variability of sediment exported from five river catchments with varying hydrology and agricultural land uses over multiple years and iii) to investigate trends in relation to physical and land use characteristics when sediment data were compared between catchments. Sediment data were collected in five intensive agricultural river catchments in Ireland (3-11 km2) which featured contrasting land uses (predominantly intensive grassland or arable) and soil drainage classes (well, moderate and poor). High-resolution suspended sediment concentration data (SSC - using a calibrated turbidity proxy) were collected ex-situ and combined with in-stream discharge data measured at each catchment outlet to estimate suspended sediment yield (SSY - t km-2 yr-1). In two catchments additional in-stream turbidity monitoring equipment replicated ex-situ measurements including site specific calibration of individual in-stream and ex-situ turbidity probes. Depth-integrated samples were collected to assess the accuracy of both approaches. Method comparison results showed that true SSC values (from depth-integrated sampling) were predominantly within the 95% confidence interval of ex-situ predicted SSC consequently

  2. Natural ³⁷Ar concentrations in soil air: implications for monitoring underground nuclear explosions.

    PubMed

    Riedmann, Robin A; Purtschert, Roland

    2011-10-15

    For on-site inspections (OSI) under the Comprehensive Nuclear-Test-Ban Treaty (CTBT) measurement of the noble gas ³⁷Ar is considered an important technique. ³⁷Ar is produced underground by neutron activation of Calcium by the reaction ⁴⁰Ca(n,α)³⁷Ar. The naturally occurring equilibrium ³⁷Ar concentration balance in soil air is a function of an exponentially decreasing production rate from cosmic ray neutrons with increasing soil depth, diffusive transport in the soil air, and radioactive decay (T(1/2): 35 days). In this paper for the first time, measurements of natural ³⁷Ar activities in soil air are presented. The highest activities of ~100 mBq m⁻³ air are 2 orders of magnitude larger than in the atmosphere and are found in 1.5-2.5 m depth. At depths > 8 m ³⁷Ar activities are < 20 mBq m⁻³ air. After identifying the main ³⁷Ar production and gas transport factors the expected global activity range distribution of ³⁷Ar in shallow subsoil (0.7 m below the surface) was estimated. In high altitude soils, with large amounts of Calcium and with low gas permeability, ³⁷Ar activities may reach values up to 1 Bq m⁻³.

  3. Decomposition Odour Profiling in the Air and Soil Surrounding Vertebrate Carrion

    PubMed Central

    2014-01-01

    Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains. PMID:24740412

  4. Decomposition odour profiling in the air and soil surrounding vertebrate carrion.

    PubMed

    Forbes, Shari L; Perrault, Katelynn A

    2014-01-01

    Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains.

  5. Glomalin accumulated in seagrass sediments reveals past alterations in soil quality due to land-use change

    NASA Astrophysics Data System (ADS)

    López-Merino, Lourdes; Serrano, Oscar; Adame, María Fernanda; Mateo, Miguel Ángel; Martínez Cortizas, Antonio

    2015-10-01

    Arbuscular mycorrhizal fungi (AMF), symbionts with most terrestrial plants, produce glomalin-related soil protein (GRSP), which plays a major role in soil structure and quality. Both fungi hyphae and protein production in soils are affected by perturbations related to land-use changes, implying that GRSP is a sensitive indicator of soil quality. Unfortunately, GRSP degrades within years to decades in oxic environments, preventing its use as palaeoecological proxy. However, GRSP is transported to marine, near-shore anoxic sediments, where it accumulates and remains non-degraded, enabling the assessment of its potential as a palaeoecological proxy for soil ecosystem's health. Exploiting this fact, we have obtained for the first time a long-term record (c. 1250 years) of GRSP content using a Posidonia oceanica seagrass mat sediment core from the Western Mediterranean (Portlligat Bay, Spain). The trends in GRSP content matched well with land-use changes related to agrarian activities reconstructed by pollen analysis. In periods of cultivation, GRSP accumulation in the mat decreased. Given the role played by GRSP, the results suggest that agrarian intensification may have resulted in perturbations to soil quality. Thus, GRSP in seagrass mat sediments can be used to assess long-term trends in continental soil quality induced by human activities. These findings open new possibilities in long-term ecology research, as other anoxic environments could be potentially valid too. Testing them would open the possibility to identify long-term patterns in soil quality and other environmental stressors that could also affect AMF and GRSP production in soils.

  6. Late Holocene Soil Stratigraphy and Geochronology of Alluvial Sedimentation in the Sonoran Desert, Arizona

    NASA Astrophysics Data System (ADS)

    Bacon, S. N.; McDonald, E. V.; Dalldorf, G. K.; Caldwell, T. G.

    2007-12-01

    The integration of soil stratigraphic investigations and radiocarbon dating at two sites in combination with geomorphic mapping at scales of 1:50k and 1:5k offer insight to the timing and magnitude of alluvial sedimentation during the late Holocene within the Sonoran Desert near Yuma, Arizona. Mapping at 1:50k was performed over an area of 3400 km2 and alluvial landforms were labeled Qf1 to Qf5, from oldest to youngest, using 1- and 5-meter resolution satellite imagery within the U.S. Army Yuma Proving Ground (YPG). Approximately 70% of the identified landforms within YPG are Quaternary alluvial fans, alluvial plains, and active washes, whereas the other 30% consist of mountain highlands, pediments, and badlands. In the southwest portion of YPG near Muggins Mountains, alluvial fan terraces (Qf4) positioned 0.5 m above active washes are characterized as having moderate bar-and-swale microtopography, moderately developed desert pavement, and a Av/ Bw/ Cky/ Cky1/ Cky2/ Cky3 gravelly soil profile. A large piece of charcoalized Ironwood ( Olneya tesota) was recovered from a depth of 0.75 m and yielded three AMS 14C dates that range from 3330 to 2860 cal yr B.P. Geomorphic mapping at a scale of 1:5k indicates that in an area of 25 km2 at the site, the distribution of late Holocene alluvial fan terraces comprise 17% of the surrounding Quaternary alluvium. Similar aged alluvial features were observed about 70 km to the north near South Trigo Peak at YPG. Terraces of a broad and flat alluvial plain positioned 0.5 m above active channels are characterized as having moderate bar- and-swale microtopography, poorly developed desert pavement, and a AC/ C/ Bwkb1/ Bwk1b2/ Bwk2b2/ BCkb2/ Bwkb3 sandy soil profile. A terrestrial gastropod shell ( Lymnea sp.) fragment was recovered from a depth of 0.5 m and yielded an AMS 14C date of 2360-2310 cal yr B.P. Additional geomorphic mapping at 1:5k shows that in an area of 30 km2, the distribution of late Holocene alluvial plain terraces

  7. Polybrominated diphenyl ethers in soils, sediments, and human hair in a plastic waste recycling area: a neglected heavily polluted area.

    PubMed

    Tang, Zhenwu; Huang, Qifei; Cheng, Jiali; Yang, Yufei; Yang, Jun; Guo, Wei; Nie, Zhiqiang; Zeng, Ning; Jin, Lu

    2014-01-01

    The release of pollutants during the recycling of contaminated plastics is a problem which has drawn worldwide attention; however, little information on the transfer of polybrominated diphenyl ethers (PBDEs) in these processes is available. We conducted a survey of PBDEs in soils, sediments, and human hair in a typical plastic waste recycling area in northern China. The total concentrations (ng/g) of 21 PBDEs were 1.25-5504 (average 600), 18.2-9889 (average 1619), and 1.50-861 (average 112) in soils, sediments, and hair, respectively. The PBDE concentrations were comparable to concentrations observed in e-waste recycling areas; however, the concentrations in soils and sediments were 1-3 orders of magnitude higher than in other areas, and the concentrations in hair were much higher than in other areas. This indicates that this area is highly polluted with PBDEs. BDE-209 was the dominant congener (representing 91.23%, 92.3%, and 91.5% of the total PBDEs observed in soils, sediments, and hair, respectively), indicating that the commercial deca-BDE product was dominant. The commercial penta- and octa-BDE products made small contributions to the total PBDE concentrations, unlike what has been found in some e-waste recycling areas. Our results show that crude plastic waste processing is a major contributor of PBDEs to the environment and humans, which should be of great concern.

  8. PERFORMANCE OF THE CAPE TECHNOLOGIES DF1 DIOXIN/FURAN IMMUNOASSAY KIT FOR SOIL AND SEDIMENT SAMPLES

    EPA Science Inventory

    A demonstration of screening technologies for determining the presence of dioxin and dioxin-like compounds in soil and sediment was conducted under the U.S. Environmental Protection Agency’s (EPA’s) Superfund Innovative Technology Evaluation Program in Saginaw, Michigan in 2004. ...

  9. INTERIM REPORT ON THE EVOLUTION AND PERFORMANCE OF THE EICHROM TECHNOLOGIES PROCEPT RAPID DIOXIN ASSAY FOR SOIL AND SEDIMENT SAMPLES

    EPA Science Inventory

    A demonstration of screening technologies for determining the presence of dioxin and dioxin-like compounds in soil and sediment was conducted under the U.S. Environmental Protection Agency's(EPA's) Superfund Innovative Technology Evaluation Program in Saginaw, Michigan in 2004. T...

  10. Final Report on the Performance of the Eichrom Technologies Procept® Rapid Dioxin Assay for Soil and Sediment Samples

    EPA Science Inventory

    A demonstration of screening technologies for determining the presence of dioxin and dioxin-like compounds in soil and sediment was conducted under the U.S. Environmental Protection Agency’s (EPA’s) Superfund Innovative Technology Evaluation Program in Saginaw, Michigan in 2004. ...

  11. Determination of mercury in rocks, sediments, and soils by flameless atomic absorption

    SciTech Connect

    White, L.E.; Carter, M.H. Jr.

    1980-05-22

    A simple, relatively fast method for the determination of mercury in rocks, sediments, and soils has been developed to meet the needs of the National Uranium Resources Evaluation Project. One gram of the less than 100 mesh material is placed in a 250-mL reagent bottle and is digested using a mixture of concentrated sulfuric acid and 30% hydrogen peroxide. To prevent the loss of mercury during the digestion procedure, an 18-inch dry reflux tower is employed. After digestion, the sample is treated with 5% potassium permanganate solution, and a sodium chloride-hydroxylamine sulfate reagent. Tin (11) sulfate is then added and the sample immediately attached to an aeration device. The volatilized mercury is swept into an absorption cell by an argon stream and is measured by an atomic absorption spectrophotometer adjusted to 253.7 nanometer wave-length. Absorption is then plotted by a strip chart recorder.

  12. Comparison of fate profiles of PAHs in soil, sediments and mangrove leaves after oil spills by QSAR and QSPR.

    PubMed

    Tansel, Berrin; Lee, Mengshan; Tansel, Derya Z

    2013-08-15

    First order removal rates for 15 polyaromatic hydrocarbons (PAHs) in soil, sediments and mangrove leaves were compared in relation to the parameters used in fate transport analyses (i.e., octanol-water partition coefficient, organic carbon-water partition coefficient, solubility, diffusivity in water, HOMO-LUMO gap, molecular size, molecular aspect ratio). The quantitative structure activity relationships (QSAR) and quantitative structure property relationships (QSPR) showed that the rate of disappearance of PAHs is correlated with their diffusivities in water as well as molecular volumes in different media. Strong correlations for the rate of disappearance of PAHs in sediments could not be obtained in relation to most of the parameters evaluated. The analyses showed that the QSAR and QSPR correlations developed for removal rates of PAHs in soils would not be adequate for sediments and plant tissues.

  13. Comparison of fate profiles of PAHs in soil, sediments and mangrove leaves after oil spills by QSAR and QSPR.

    PubMed

    Tansel, Berrin; Lee, Mengshan; Tansel, Derya Z

    2013-08-15

    First order removal rates for 15 polyaromatic hydrocarbons (PAHs) in soil, sediments and mangrove leaves were compared in relation to the parameters used in fate transport analyses (i.e., octanol-water partition coefficient, organic carbon-water partition coefficient, solubility, diffusivity in water, HOMO-LUMO gap, molecular size, molecular aspect ratio). The quantitative structure activity relationships (QSAR) and quantitative structure property relationships (QSPR) showed that the rate of disappearance of PAHs is correlated with their diffusivities in water as well as molecular volumes in different media. Strong correlations for the rate of disappearance of PAHs in sediments could not be obtained in relation to most of the parameters evaluated. The analyses showed that the QSAR and QSPR correlations developed for removal rates of PAHs in soils would not be adequate for sediments and plant tissues. PMID:23756470

  14. Coal mining activities change plant community structure due to air pollution and soil degradation.

    PubMed

    Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

    2014-10-01

    The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

  15. Hydrogeochemical zonation in intertidal salt marsh sediments: evidence of positive plant-soil feedback?

    NASA Astrophysics Data System (ADS)

    Moffett, K. B.; Dittmar, J.; Seyfferth, A.; Fendorf, S.; Gorelick, S.

    2012-12-01

    Surface and subsurface environments are linked by the biogeochemical activity in near-surface sediment and by the hydrological fluxes that mobilize its reagents and products. A particularly dynamic and interesting setting to study near-surface hydrogeochemistry is the intertidal zone. Here, the very strong tidal hydraulic forcing is often thought to dominate water and solute transport. However, we demonstrated the importance of two additional subsurface drivers: groundwater flow and plant root water uptake. A high-resolution, coupled surface water-groundwater model of an intertidal salt marsh in San Francisco Bay, CA showed that these three drivers vary over different spatial scales: tidal flooding varies over 10's of meters; groundwater flow varies over meters, particularly within channel banks; and plant root water uptake varies in 3D at the sub-meter scale. Expanding on this third driver, we investigated whether the spatial variations in soil-water-plant hydraulic interactions that occur due to vegetation zonation also cause distinct geochemical zonation in salt marsh sediment pore waters. The existence of such geochemical zonation was verified and mapped by detailed field observations of the chemical composition of sediments, pore waters, surface waters, and vegetation. The field data and the coupled hydrologic model were then further analyzed to evaluate potential causal mechanisms for the geochemical zonation, including testing the hypothesis that the vegetation affects pore water geochemistry via a positive feedback beneficial to itself. If further supported by future studies, this geochemical feedback may complement known physical ecosystem engineering mechanisms to help stabilize and organize intertidal wetlands.

  16. Optimizing the removal of carbon phases in soils and sediments for sequential chemical extractions by coulometry.

    PubMed

    Schultz, M K; Biegalski, S R; Inn, K G; Yu, L; Burnett, W C; Thomas, J L; Smith, G E

    1999-04-01

    We have developed a coulometric technique to optimize the removal of the carbonate and organic fractions for sequential chemical extractions of soils and sediments. The coulometric system facilitates optimizing these two fractions by direct real-time measurement of carbon dioxide (CO2) evolved during the removal of these two fractions. Further analyses by ICP-MS and alpha-spectrometry aided in interpreting the results of coulometry experiments. The effects of time, temperature, ionic strength and pH were investigated. The sensitivity of the coulometric reaction vessel/detection system was sufficient even at very low total carbon content (< 0.1 mol kg-1). The efficiency of the system is estimated to be 96% with a standard deviation of 8%. Experiments were carried out using NIST Standard Reference Materials 4357 Ocean Sediment (OS), 2704 Buffalo River Sediment (BRS), and pure calcium carbonate. Carbonate minerals were dissolved selectively using an ammonium acetate-acetic acid buffer. Organic matter was then oxidized to CO2 using hydrogen peroxide (H2O2) in nitric acid. The carbonate fraction was completely dissolved within 120 min under all conditions examined (literature suggests up to 8 h). For the OS standard, the oxidation of organic matter self-perpetuates between 45 and 50 degrees C, a factor of two less than commonly suggested, while organic carbon in the BRS standard required 80 degrees C for the reaction to proceed to completion. For complete oxidation of organic matter, we find that at least three additions of H2O2 are required (popular methods suggest one or two).

  17. Renewed soil erosion and remobilisation of radioactive sediment in Fukushima coastal rivers after the 2013 typhoons.

    PubMed

    Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Lepage, Hugo; Cerdan, Olivier; Lefèvre, Irène; Ayrault, Sophie

    2014-04-03

    Summer typhoons and spring snowmelt led to the riverine spread of continental Fukushima fallout to the coastal plains of Northeastern Japan and the Pacific Ocean. Four fieldwork campaigns based on measurement of radioactive dose rates in fine riverine sediment that has recently deposited on channel bed-sand were conducted between November 2011 and May 2013 to document the spread of fallout by rivers. After a progressive decrease in the fresh riverine sediment doses rates between 2011 and early spring in 2013, a fifth campaign conducted in November 2013 showed that they started to increase again after the occurrence of violent typhoons. We show that this increase in dose rates was mostly due to remobilization of contaminated material that was temporarily stored in river channels or, more importantly, in dam reservoirs of the region during the typhoons. In addition, supply of particles from freshly eroded soils in autumn 2013 was the most important in areas where decontamination works are under progress. Our results underline the need to monitor the impact of decontamination works and dam releases in the region, as they may provide a continuous source of radioactive contamination to the coastal plains and the Pacific Ocean during the coming years.

  18. Renewed soil erosion and remobilisation of radioactive sediment in Fukushima coastal rivers after the 2013 typhoons

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Lepage, Hugo; Cerdan, Olivier; Lefèvre, Irène; Ayrault, Sophie

    2014-04-01

    Summer typhoons and spring snowmelt led to the riverine spread of continental Fukushima fallout to the coastal plains of Northeastern Japan and the Pacific Ocean. Four fieldwork campaigns based on measurement of radioactive dose rates in fine riverine sediment that has recently deposited on channel bed-sand were conducted between November 2011 and May 2013 to document the spread of fallout by rivers. After a progressive decrease in the fresh riverine sediment doses rates between 2011 and early spring in 2013, a fifth campaign conducted in November 2013 showed that they started to increase again after the occurrence of violent typhoons. We show that this increase in dose rates was mostly due to remobilization of contaminated material that was temporarily stored in river channels or, more importantly, in dam reservoirs of the region during the typhoons. In addition, supply of particles from freshly eroded soils in autumn 2013 was the most important in areas where decontamination works are under progress. Our results underline the need to monitor the impact of decontamination works and dam releases in the region, as they may provide a continuous source of radioactive contamination to the coastal plains and the Pacific Ocean during the coming years.

  19. Biodegradation of naphthenic acids in oils sands process waters in an immobilized soil/sediment bioreactor.

    PubMed

    McKenzie, Natalie; Yue, Siqing; Liu, Xudong; Ramsay, Bruce A; Ramsay, Juliana A

    2014-08-01

    Aqueous extraction of bitumen in the Alberta oil sands industry produces large volumes of oil sands process water (OSPW) containing naphthenic acids (NAs), a complex mixture of carboxylic acids that are acutely toxic to aquatic organisms. Although aerobic biodegradation reduces NA concentrations and OSPW toxicity, treatment times are long, however, immobilized cell reactors have the potential to improve NA removal rates. In this study, two immobilized soil/sediment bioreactors (ISBRs) operating in series were evaluated for treatment of NAs in OSPW. A biofilm was established from microorganisms associated with sediment particles from an OSPW contaminated wetland on a non-woven textile. At 16 months of continuous operation with OSPW as the sole source of carbon and energy, 38±7% NA removal was consistently achieved at a residence time of 160 h at a removal rate of 2.32 mg NAs L(-1)d(-1). The change in NA profile measured by gas chromatography-mass spectrometry indicated that biodegradability decreased with increasing cyclicity. These results indicate that such treatment can significantly reduce NA removal rates compared to most studies, and the treatment of native process water in a bioreactor has been demonstrated. Amplification of bacterial 16S rRNA genes and sequencing using Ion Torrent sequencing characterized the reactors' biofilm populations and found as many as 235 and 198 distinct genera in the first and second bioreactor, respectively, with significant populations of ammonium- and nitrite-oxidizers.

  20. Air-Based Remediation Workshop - Section 2 Soil Vapor Extraction

    EPA Science Inventory

    Pursuant to the EPA-AIT Implementing Arrangement 7 for Technical Environmental Collaboration, Activity 11 "Remediation of Contaminated Sties," the USEPA Office of International Affairs Organized a Forced Air Remediation Workshop in Taipei to deliver expert training to the Environ...

  1. Threshold velocities for input of soil particles into the air by desert soils

    SciTech Connect

    Gillette, D.A.; Adams, J.; Endo, A.; Smith, D.; Kihl, R.

    1980-10-20

    Desert soils mostly from the Mojave Desert were tested for threshold friction velocity (the friction velocity above which soil erosion takes place) with an open-bottomed portable wind tunnel. Several geomorphological settings were chosen to be representative of much of the surface of the Mojave Desert, for example, playas, alluvial fans, and aeolian features. Variables which increase threshold velocity are decreasing proportion of sand, increasing size of dry aggregates of the soil, and increasing fraction of the soil mass larger than 1 mm. Threshold velocity increases with different types of soil surfaces in the following order: disturbed soils (except disturbed heavy clay soils), sand dunes, alluvial and aeolian sand deposits, disturbed playa soils, skirts of playas, playa centers, and desert pavement (alluvial deposits). 21 references, 5 figures, 6 tables.

  2. Comparing radiation dose rates in soils and riverine sediment to track the dispersion of radioactive contamination in Fukushima coastal rivers

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Onda, Yuichi; Lepage, Hugo; Chartin, Caroline; Lefèvre, Irène; Cerdan, Olivier; Bonté, Philippe; Ayrault, Sophie

    2014-05-01

    The Fukushima Dai-ichi nuclear power plant (FDNPP) accident that occurred in March 2011 led to the formation of a 3000-km² radioactive pollution plume on soils located up to 70 km to the northwest of the damaged site. Forests and paddy fields are the dominant land uses in this mountainous region drained to the Pacific Ocean by several rivers that flow across densely inhabited coastal plains. It is then crucial to track the dispersion of radioactive material conveyed by those rivers to estimate the continental supply of radionuclides to the Ocean and to assess redistribution of radioactive sediment in those catchments. Radiations emitted by this contaminated material may indeed lead to an external exposure threat for local populations. As river discharge and sediment concentration data were not available during the first two years that followed the accident, alternative methods had to be developed to track this dispersion. We therefore organized field campaigns every six months and conducted local ground dose rate measurements to estimate whether fresh sediment drape deposits were more or less contaminated compared to local soils. Overall, our results showed that, in those regions exposed to violent typhoons and spring snowmelt, transfers of sediment are massive and episodic, and that they followed a seasonal cycle in 2011-2012. Then, in May 2013, contamination levels measured in sediment found in the upper parts of the catchments were almost systematically lower than the ones measured in nearby soils, whereas their contamination was higher in the coastal plains. This could have indicated a drying-up of the upstream sources of contamination. However, after the violent typhoons that occurred during summer in 2013, dose rates measured in fresh sediment deposits in November 2013 increased again systematically across the region. We thereby suggest that remobilization of contaminated sediment by typhoons and their storage in reservoirs and in coastal sections of the

  3. Soil erosion and sediment yield prediction on catchment and regional scale using a process based simulation model

    NASA Astrophysics Data System (ADS)

    Schindewolf, Marcus; Schmidt, Jürgen

    2010-05-01

    The prevention of erosion is one of the main issues in the EU-Water Framework Directive (WFD) and the European Agricultural Fund for Rural Development (EAFRD). Planning and dimensioning of soil conservation measures require reliable and detailed information on the temporal and spatial distribution of soil detachment, soil transport and deposition. Soil erosion models are increasingly used, in order to simulate the physical processes involved and to predict the effects of soil erosion control measures. In this study the EROSION 3D simulation model is used for surveying soil erosion and deposition on the catchment scale covering the entire state of Saxony/Germany (18.500 km²). EROSION 3D is a distributed, extensively validated GIS based soil loss and deposition model including sediment delivery to surface water bodies. However, the application of the model for an entire state is a new challenge, because of the enormous data requirements and complex data processing operations prior to simulation. In this context the study includes the compilation, validation and generalisation of existing land use and soil data in order to generate a consistent EROSION 3D input dataset for the entire state of Saxony. As a part of this process the interface software DPROC allows to transfer the original soil and land use data into model specific data. The project aims to extend the interface software DPROC by an interactive GIS-component which enables the user to select arbitrary hydrological watersheds including the related soil and land use data. Based on these data DPROC automatically creates the according EROSION 3D input files using a relational database of primary data and model specific data. DPROC uses parameter transfer tables in order to specify the relationship between primary soil and land use data and model specific data. This combined methodology provides different risk assessment maps for certain demands on the regional scale of a Federal State. Besides soil loss and

  4. Treatment of plutonium contaminated soil/sediment from the Mound site using the ACT*DE*CON{sup SM} process

    SciTech Connect

    Negri, M.C.; Swift, N.A.; North, J.P.

    1996-10-01

    The removal and/or treatment of contaminated soil is a major problem facing the US DOE. The EG&G Mound Applied Technologies site in Miamisburg, Ohio, has an estimated 1.5 million cubic feet of soils from past disposal and waste burial practices awaiting remediation from plutonium contamination. This amount includes sediment from the Miami-Erie Canal that was contaminated in 1969 following a pipe- rupture accident. Conventional soil washing techniques that use particle separation would generate too large a waste volume to be economically feasible. Therefore, innovative technologies are needed for the cleanup. The ACT*DE*CON process was developed by SELENTEC for washing soils to selectively dissolve and remove heavy metals and radionuclides. ACT*DE*CON chemically dissolves and removes heavy metals and radionuclides from soils and sediments into an aqueous medium. The ACT*DE*CON process uses oxidative carbonate/chelant chemistry to dissolve the contaminant from the sediment and hold the contaminant in solution. The objective of recent work was to document the proves conditions necessary to achieve the Mound-site and regulatory-cleanup goals using the ACT*DE*CON technology.

  5. Hot air injection for removal of dense, non-aqueous-phase liquid contaminants from low-permeability soils

    SciTech Connect

    Payne, F.C.

    1996-08-01

    The performance of soil vapor extraction systems for the recovery of volatile and semi-volatile organic compounds is potentially enhanced by the injection of heated air to increase soil temperatures. The soil temperature increase is expected to improve soil vapor extraction (SVE) performance by increasing target compound vapor pressures and by increasing soil permeability through drying. The vapor pressure increase due to temperature rise relieves the vapor pressure limit on the feasibility of soil vapor extraction. However, the system still requires an air flow through the soil system to deliver heat and to recover mobilized contaminants. Although the soil permeability can be increased through drying, very low permeability soils and low permeability soils adjacent to high permeability air flow pathways will be treated slowly, if at all. AR thermal enhancement methods face this limitation. Heated air injection offers advantages relative to other thermal techniques, including low capital and operation costs. Heated air injection is at a disadvantage relative to other thermal techniques due to the low heat capacity of air. To be effective, heated air injection requires that higher air flows be established than for steam injection or radio frequency heating. Heated air injection is not economically feasible for the stratified soil system developed as a standard test for this document. This is due to the inability to restrict heated air flow to the clay stratum when a low-resistance air flow pathway is available in the adjoining sand. However, the technology should be especially attractive, both technically and economically, for low-volatile contaminant recovery from relatively homogeneous soil formations. 16 refs., 2 tabs.

  6. Soil concentrations, occurrence, sources and estimation of air-soil exchange of polychlorinated biphenyls in Indian cities.

    PubMed

    Chakraborty, Paromita; Zhang, Gan; Li, Jun; Selvaraj, Sakthivel; Breivik, Knut; Jones, Kevin C

    2016-08-15

    Past studies have shown potentially increasing levels of polychlorinated biphenyls (PCBs) in the Indian environment. This is the first attempt to investigate the occurrence of PCBs in surface soil and estimate diffusive air-soil exchange, both on a regional scale as well as at local level within the metropolitan environment of India. From the north, New Delhi and Agra, east, Kolkata, west, Mumbai and Goa and Chennai and Bangalore in the southern India were selected for this study. 33 PCB congeners were quantified in surface soil and possible sources were derived using positive matrix factorization model. Net flux directions of PCBs were estimated in seven major metropolitan cities of India along urban-suburban-rural transects. Mean Σ33PCBs concentration in soil (12ng/g dry weight) was nearly twice the concentration found in global background soil, but in line with findings from Pakistan and urban sites of China. Higher abundance of the heavier congeners (6CB-8CB) was prevalent mostly in the urban centers. Cities like Chennai, Mumbai and Kolkata with evidence of ongoing PCB sources did not show significant correlation with soil organic carbon (SOC). This study provides evidence that soil is acting as sink for heavy weight PCB congeners and source for lighter congeners. Atmospheric transport is presumably a controlling factor for occurrence of PCBs in less polluted sites of India.

  7. Transformation of marine sediment to paddy soil: Primary marine, lacustrine, and land plant lipids

    NASA Astrophysics Data System (ADS)

    Mueller-Niggemann, Cornelia; Cao, Zhihong; Schwark, Lorenz

    2010-05-01

    More than fifty percent of the world's population feeds on rice. The continuous population increase and urban sprawl leads to an ever-increasing demand for new rice cultivation area, in particular China. For centuries suitable coastal areas in China have been exploited for land reclamation, i.e. conversion of coastal marine and lacustrine marshlands into rice paddy fields. Flooded rice paddies are considered one of the major biogenic sources of methane into the atmospheric. Methane is thought to be about 30 times more efficient as greenhouse gas, when compared to carbon dioxide. Overall, rice fields are assumed to contribute app. 10-25% to global CH4 production. It is thus paramount importance to study the effects of increasing rice cultivation and land reclamation in China. For global carbon cycle investigation, it is crucial whether paddy soils, due to their large extent and higher carbon turnover, serve as carbon (CO2) sinks or sources. Here we present results from a chronosequence study of paddy soils with different and well known starting dates of cultivation, in the Zhejiang province (Yangtze River delta) by land reclamation through the building of protective dikes over the past 2000 years. Two end members of natural sediments subjected to land reclamation, a marine tidal mudflat in the Yangtze delta and a coastal lake, represent the substrate on which the paddy soil evolution started. Dike systems were constructed 2000, 1000, 700, 300, 100, and 50 years before present. We are thus able to follow the evolution of rice paddy soils developed on marine sediments using eight well defined tie-points. This chronosequence is then used for assessing the relative proportion of primary marine or lacustrine organic matter preserved in present day soils and to identify the amount and composition of organic matter added since cultivation started. Paddy soil management introduces rice plants debris and exudates as well as rice-associated microbial biomass (covered in a

  8. (210)Pb as a tracer of soil erosion, sediment source area identification and particle transport in the terrestrial environment.

    PubMed

    Matisoff, Gerald

    2014-12-01

    Although (137)Cs has been used extensively to study soil erosion and particle transport in the terrestrial environment, there has been much less work using excess or unsupported (210)Pb ((210)Pbxs) to study the same processes. Furthermore, since (137)Cs activities in soils are decreasing because of radioactive decay, some locations have an added complication due to the addition of Chernobyl-derived (137)Cs, and the activities of (137)Cs in the southern hemisphere are low, there is a need to develop techniques that use (210)Pbxs to provide estimates of rates of soil erosion and particle transport. This paper reviews the current status of (210)Pbxs methods to quantify soil erosion rates, to identify and partition suspended sediment source areas, and to determine the transport rates of particles in the terrestrial landscape. Soil erosion rates determined using (210)Pbxs are based on the unsupported (210)Pb ((210)Pbxs) inventory in the soil, the depth distribution of (210)Pbxs, and a mass balance calibration ('conversion model') that relates the soil inventory to the erosion rate using a 'reference site' at which neither soil erosion nor soil deposition has occurred. In this paper several different models are presented to illustrate the effects of different model assumptions such as the timing, depth and rates of the surface soil mixing on the calculated erosion rates. The suitability of model assumptions, including estimates of the depositional flux of (210)Pbxs to the soil surface and the post-depositional mobility of (210)Pb are also discussed. (210)Pb can be used as one tracer to permit sediment source area identification. This sediment 'fingerprinting' has been extended far beyond using (210)Pb as a single radioisotope to include numerous radioactive and stable tracers and has been applied to identifying the source areas of suspended sediment based on underlying rock type, land use (roads, stream banks, channel beds, cultivated or uncultivated lands, pasture lands

  9. Estimation of soil air permeability components at a laboratory-scale pilot.

    PubMed

    Boudouch, Otmane; Esrael, Daoud; Kacem, Mariem; Benadda, Belkacem

    2012-01-01

    Soil air permeability is a key parameter in the design of soil vapour extraction. The purpose of this study is to verify the applicability of different analytical solutions, developed to determine soil characteristics in field conditions, to estimate soil air permeability in a small-scale pilot, since field testing may be expensive. A laboratory tridirectional pilot and a unidirectional column were designed in order to achieve the objectives of this work. Use of a steady-state unconfined analytical solution was found to be an appropriate method to determine soil air permeability components for the pilot conditions. Using pressure data collected under open, steady-state conditions, the average values of radial and vertical permeability were found to be, respectively, 9.97 x 10(-7) and 8.74 x 10(-7) cm2. The use of semi-confined analytical solutions may not be suitable to estimate soil parameters since a significant difference was observed between simulated and observed vacuums. Air permeability was underestimated when transient solutions were used, in comparison with methods based on steady-state solutions. The air radial and vertical permeability was found to be, respectively, 7.06 x 10(-7) and 4.93 x 10(-7) cm2, in the open scenario, and 2.30 x 10(-7) and 1.51 x 10(-7) cm2 in the semi-confined scenario. However, a good estimate of soil porosity was achieved using the two transient methods. The average values were predicted to be 0.482, in the open scenario, and 0.451 in the semi-confined scenario, which was in good agreement with the real value.

  10. Impact of gold mining associated with mercury contamination in soil, biota sediments and tailings in Kenya.

    PubMed

    Odumo, Benjamin Okang'; Carbonell, Gregoria; Angeyo, Hudson Kalambuka; Patel, Jayanti Purshottam; Torrijos, Manuel; Rodríguez Martín, José Antonio

    2014-11-01

    This work considered the environmental impact of artisanal mining gold activity in the Migori-Transmara area (Kenya). From artisanal gold mining, mercury is released to the environment, thus contributing to degradation of soil and water bodies. High mercury contents have been quantified in soil (140 μg kg(-1)), sediment (430 μg kg(-1)) and tailings (8,900 μg kg(-1)), as expected. The results reveal that the mechanism for transporting mercury to the terrestrial ecosystem is associated with wet and dry depositions. Lichens and mosses, used as bioindicators of pollution, are related to the proximity to mining areas. The further the distance from mining areas, the lower the mercury levels. This study also provides risk maps to evaluate potential negative repercussions. We conclude that the Migori-Transmara region can be considered a strongly polluted area with high mercury contents. The technology used to extract gold throughout amalgamation processes causes a high degree of mercury pollution around this gold mining area. Thus, alternative gold extraction methods should be considered to reduce mercury levels that can be released to the environment.

  11. Concentrations, atmospheric partitioning, and air-water/soil surface exchange of polychlorinated dibenzo-p-dioxin and dibenzofuran along the upper reaches of the Haihe River basin, North China.

    PubMed

    Nie, Zhiqiang; Die, Qingqi; Yang, Yufei; Tang, Zhenwu; Wang, Qi; Huang, Qifei

    2014-01-01

    Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDF) were overall measured and compared in ambient air, water, soils, and sediments along the upper reaches of the Haihe River of North China, so as to evaluate their concentrations, profiles, and to understand the processes of gas-particle partitioning and air-water/soil exchange. The following results were obtained: (1) The average concentrations (toxic equivalents, TEQs) of 2,3,7,8-PCDD/PCDF in air, water, sediment, and soil samples were 4,855 fg/m(3), 9.5 pg/L, 99.2 pg/g dry weight (dw), and 56.4 pg/g (203 fg TEQ/m(3), 0.46 pg TEQ/L, 2.2 pg TEQ/g dw, and 1.3 pg TEQ/g, respectively), respectively. (2) Although OCDF, 1,2,3,4,6,7,8-HpCDF, OCDD, and 1,2,3,4,6,7,8-HpCDD were the dominant congeners among four environmental sinks, obvious discrepancies of these congener and homologue patterns of PCDD/PCDF were observed still. (3) Significant linear correlations for PCDD/PCDF were observed between the gas-particle partition coefficient (K p) and the subcooled liquid vapor pressure (P L (0)) and octanol-air partition coefficient (K oa). (4) Fugacity fraction values of air-water exchange indicated that most of PCDD/PCDF homologues were dominated by net volatilization from water into air. The low-chlorinated PCDD/PCDF (tetra- to hexa-) presented a strong net volatilization from the soil into air, while high-chlorinated PCDD/PCDF (hepta- to octa-) were mainly close to equilibrium for air-soil exchange. PMID:24643387

  12. Utilization of air pollution control residues for the stabilization/solidification of trace element contaminated soil.

    PubMed

    Travar, I; Kihl, A; Kumpiene, J

    2015-12-01

    The aim of this study was to evaluate the stabilization/solidification (S/S) of trace element-contaminated soil using air pollution control residues (APCRs) prior to disposal in landfill sites. Two soil samples (with low and moderate concentrations of organic matter) were stabilized using three APCRs that originated from the incineration of municipal solid waste, bio-fuels and a mixture of coal and crushed olive kernels. Two APCR/soil mixtures were tested: 30% APCR/70% soil and 50% APCR/50% soil. A batch leaching test was used to study immobilization of As and co-occurring metals Cr, Cu, Pb and Zn. Solidification was evaluated by measuring the unconfined compression strength (UCS). Leaching of As was reduced by 39-93% in APCR/soil mixtures and decreased with increased amounts of added APCR. Immobilization of As positively correlated with the amount of Ca in the APCR and negatively with the amount of soil organic matter. According to geochemical modelling, the precipitation of calcium arsenate (Ca3(AsO4)2/4H2O) and incorporation of As in ettringite (Ca6Al2(SO4)3(OH)12 · 26H2O) in soil/APCR mixtures might explain the reduced leaching of As. A negative effect of the treatment was an increased leaching of Cu, Cr and dissolved organic carbon. Solidification of APCR/soil was considerably weakened by soil organic matter.

  13. Dynamics of air gap formation around roots with changing soil water content.

    NASA Astrophysics Data System (ADS)

    Vetterlein, D.; Carminati, A.; Weller, U.; Oswald, S.; Vogel, H.-J.

    2009-04-01

    Most models regarding uptake of water and nutrients from soil assume intimate contact between roots and soil. However, it is known for a long time that roots may shrink under drought conditions. Due to the opaque nature of soil this process could not be observed in situ until recently. Combining tomography of the entire sample (field of view of 16 x 16 cm, pixel side 0.32 mm) with local tomography of the soil region around roots (field of view of 5 x 5 cm, pixel side 0.09 mm), the high spatial resolution required to image root shrinkage and formation of air-filled gaps around roots could be achieved. Applying this technique and combining it with microtensiometer measurements, measurements of plant gas exchange and microscopic assessment of root anatomy, a more detailed study was conducted to elucidate at which soil matric potential roots start to shrink in a sandy soil and which are the consequences for plant water relations. For Lupinus albus grown in a sandy soil tomography of the entire root system and of the interface between taproot and soil was conducted from day 11 to day 31 covering two drying cycles. Soil matric potential decreased from -36 hPa at day 11 after planting to -72, -251, -429 hPa, on day 17, 19, 20 after planting. On day 20 an air gap started to occur around the tap root and extended further on day 21 with matric potential below -429 hPa (equivalent to 5 v/v % soil moisture). From day 11 to day 21 stomatal conductivity decreased from 467 to 84 mmol m-2 s-1, likewise transpiration rate decreased and plants showed strong wilting symptoms on day 21. Plants were watered by capillary rise on day 21 and recovered completely within a day with stomatal conductivity increasing to 647 mmol m-2 s-1. During a second drying cycle, which was shorter as plants continuously increased in size, air gap formed again at the same matric potential. Plant stomatal conductance and transpiration decreased in a similar fashion with decreasing matric potential and

  14. Modelling soil erosion and associated sediment yield for small headwater catchments of the Daugava spillway valley, Latvia

    NASA Astrophysics Data System (ADS)

    Soms, Juris

    2015-04-01

    The accelerated soil erosion by water and associated fine sediment transfer in river catchments has various negative environmental as well as economic implications in many EU countries. Hence, the scientific community had recognized and ranked soil erosion among other environmental problems. Moreover, these matters might worsen in the near future in the countries of the Baltic Region, e.g. Latvia considering the predicted climate changes - more precisely, the increase in precipitation and shortening of return periods of extreme rainfall events, which in their turn will enable formation of surface runoff, erosion and increase of sediment delivery to receiving streams. Thereby it is essential to carry out studies focused on these issues in order to obtain reliable data in terms of both scientific and applied aims, e.g. environmental protection and sustainable management of soils as well as water resources. During the past decades, many of such studies of soil erosion had focused on the application of modelling techniques implemented in a GIS environment, allowing indirectly to estimate the potential soil losses and to quantify related sediment yield. According to research results published in the scientific literature, this approach currently is widely used all over the world, and most of these studies are based on the USLE model and its revised and modified versions. Considering that, the aim of this research was to estimate soil erosion rates and sediment transport under different hydro-climatic conditions in south-eastern Latvia by application of GIS-based modelling. For research purposes, empirical RUSLE model and ArcGIS software were applied, and five headwater catchments were chosen as model territories. The selected catchments with different land use are located in the Daugava spillway valley, which belongs to the upper Daugava River drainage basin. Considering lithological diversity of Quaternary deposits, a variety of soils can be identified, i.e., Stagnic

  15. Ecological Screening Values for Surface Water, Sediment, and Soil: 2005 Update

    SciTech Connect

    Friday, G. P.

    2005-07-18

    One of the principal components of the environmental remediation program at the Savannah River Site (SRS) is the assessment of ecological risk. Used to support CERCLA, RCRA, and DOE orders, the ecological risk assessment (ERA) can identify environmental hazards and evaluate remedial action alternatives. Ecological risk assessment is also an essential means for achieving DOE's risk based end state vision for the disposition of nuclear material and waste hazards, the decommissioning of facilities, and the remediation of inactive waste units at SRS. The complexity of an ERA ranges from a screening level ERA (SLERA) to a full baseline ERA. A screening level ecological risk assessments, although abbreviated from a baseline risk assessment, is nonetheless considered a complete risk assessment (EPA, 2001a). One of the initial tasks of any ERA is to identify constituents that potentially or adversely affect the environment. Typically, this is accomplished by comparing a constituent's maximum concentration in surface water, sediment, or soil with an ecological screening value (ESV). The screening process can eliminate many constituents from further consideration in the risk assessment, but it also identifies those that require additional evaluation. This document is an update of a previous compilation (Friday, 1998) and provides a comprehensive listing of ecological screening values for surface water, sediment, and soil. It describes how the screening values were derived and recommends benchmarks that can be used for ecological risk assessment. The sources of these updated benchmarks include the U.S. Environmental Protection Agency (EPA), U.S. Fish and Wildlife Service (USFWS), U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), Oak Ridge National Laboratory (ORNL), the State of Florida, the Canadian Council of Ministers of the Environment (CCME), the Dutch Ministry of the Environment (RIVM), and the scientific literature. It should be

  16. Air temperature evolution during dry spells and its relation to prevailing soil moisture regimes

    NASA Astrophysics Data System (ADS)

    Schwingshackl, Clemens; Hirschi, Martin; Seneviratne, Sonia I.

    2015-04-01

    The complex interplay between land and atmosphere makes accurate climate predictions very challenging, in particular with respect to extreme events. More detailed investigations of the underlying dynamics, such as the identification of the drivers regulating the energy exchange at the land surface and the quantification of fluxes between soil and atmosphere over different land types, are thus necessary. The recently started DROUGHT-HEAT project (funded by the European Research Council) aims to provide better understanding of the processes governing the land-atmosphere exchange. In the first phase of the project, different datasets and methods are used to investigate major drivers of land-atmosphere dynamics leading to droughts and heatwaves. In the second phase, these findings will be used for reducing uncertainties and biases in earth system models. Finally, the third part of the project will focus on the application of the previous findings and use them for the attribution of extreme events to land processes and possible mitigation through land geoengineering. One of the major questions in land-atmosphere exchange is the relationship between air temperature and soil moisture. Different studies show that especially during dry spells soil moisture has a strong impact on air temperature and the amplification of hot extremes. Whereas in dry and wet soil moisture regimes variations in latent heat flux during rain-free periods are expected to be small, this is not the case in transitional soil moisture regimes: Due to decreasing soil moisture content latent heat flux reduces with time, which causes in turn an increase in sensible heat flux and, subsequently, higher air temperatures. The investigation of air temperature evolution during dry spells can thus help to detect different soil moisture regimes and to provide insights on the effect of different soil moisture levels on air temperature. Here we assess the underlying relationships using different observational and

  17. Environmental study of two significant solid samples: gravitation dust sediment and soil.

    PubMed

    Remeteiová, Dagmar; Rusnák, Radoslav; Kucanová, Eva; Fióová, Beáta; Ružičková, Silvia; Fekete, Ilona; Horváth, Márk; Dirner, Vojtech

    2012-01-01

    In this work are presented results of the complex study of two significant solid environmental samples: gravitation dust sediments (industrial pollutants, potential source of risk elements input to soils) and soils (component of the environment, potential source of risk elements input to food web). The first phase of this study was focused on the study of the significant chemical properties (phase composition, content of organic and inorganic carbon) of the dust and soil samples. In the second phase, the fractionation analysis was used on the evaluation of the mobility of chosen risk elements (Cu, Ni, Pb, Zn) in the studied samples. The single-step extractions were applied in the order of the isolation of the element forms (fractions), with different mobilities during defined ecological conditions by utilization of the following reagents: 1 mol dm(-3) NH(4)NO(3) for isolation of the "mobile" fraction, 0.05 mol dm(-3) ethylenediaminetetraacetic acid and 0.43 mol dm(-3) CH(3)COOH for isolation of the "mobilizable" fraction, and 2 mol dm(-3) HNO(3) for isolation of all releasable forms. On the basis of the results obtained in this study, it is possible to state that different origins and positions of solid environmental samples in the environment reflect in different chemical properties of their matrix. The different properties of the sample matrix result in different mobilities of risk elements in these kinds of samples. The fractionation analysis with single-step extraction for isolation element fractions is the method most suitable for easy checking of environmental pollution and for evaluation of risk elements cycle in the environment.

  18. Glyphosate and AMPA contents in sediments produced by wind erosion of agricultural soils in Argentina

    NASA Astrophysics Data System (ADS)

    Aparicio, Virginia; Aimar, Silvia; De Gerónimo, Eduardo; Buschiazzo, Daniel; Mendez, Mariano; Costa, José Luis

    2014-05-01

    Wind erosion of soils is an important event in arid and semiarid regions of Argentina. The magnitude of wind erosion occurring under different management practices is relatively well known in this region but less information is available on the quality of the eroded material. Considering that the intensification of agriculture may increase the concentrations of substances in the eroded material, producing potential negative effects on the environment, we analyzed the amount of glyphosate and AMPA in sediments produced by wind erosion of agricultural soils of Argentina. Wind eroded materials were collected by means of BSNE samplers in two loess sites of the semiarid region of Argentina: Chaco and La Pampa. Samples were collected from 1 ha square fields at 13.5, 50 and 150 cm height. Results showed that at higher heights the concentrations of glyphosate and AMPA were mostly higher. The glyphosate concentration was more variable and higher in Chaco (0.66 to 313 µg kg-1) than in La Pampa (4.17 to 114 µg kg-1). These results may be due to the higher use of herbicides in Chaco, where the predominant crops are soybeans and corn, produced under no-tillage. Under these conditions the use of glyphosate for weeds control is a common practice. Conversely, AMPA concentrations were higher in La Pampa (13.1 to 101.3 µg kg-1) than in Chaco (1.3 to 83 µg kg-1). These preliminary results show high concentrations of glyphosate and AMPA in wind eroded materials of agricultural soils of Argentina. More research is needed to confirm these high concentrations in other conditions in order to detect the temporal and spatial distribution patterns of the herbicide.

  19. Model for in situ air stripping of contaminated soils: Effects of hydrocarbon adsorption

    SciTech Connect

    Mehrotra, A.K.; Karan, K.; Chakma, A.

    1996-01-01

    Soil contamination due to organic compounds is a widespread problem. The contaminants enter the soil subsurface by a number of routes, such as the disposal of wastes in landfills, spills during transportation of chemicals, plant operation, and leakage from underground storage. Air stripping as a means of soil remediation has gained popularity in recent years. In this in situ process, clean air is injected into the contaminated soil zone to volatilize and strip the contaminants, which are then removed by the carrier gas. The process has been found to be effective especially for treating the vadose zone of the soil contaminated with volatile and semivolatile organics. Nitrogen adsorption/desorption experiments in this study were performed on a soil sample to establish its desorption characteristics. A field-scale model for the air stripping process has been developed to simulate the removal of semivolatile hydrocarbons. The numerical results show that the interphase contaminant transport from the sorbed to the vapor phase plays a dominant role in influencing the process effectiveness.

  20. Fluoroquinolones and qnr genes in sediment, water, soil, and human fecal flora in an environment polluted by manufacturing discharges.

    PubMed

    Rutgersson, Carolin; Fick, Jerker; Marathe, Nachiket; Kristiansson, Erik; Janzon, Anders; Angelin, Martin; Johansson, Anders; Shouche, Yogesh; Flach, Carl-Fredrik; Larsson, D G Joakim

    2014-07-15

    There is increasing concern that environmental antibiotic pollution promotes transfer of resistance genes to the human microbiota. Here, fluoroquinolone-polluted river sediment, well water, irrigated farmland, and human fecal flora of local villagers within a pharmaceutical industrial region in India were analyzed for quinolone resistance (qnr) genes by quantitative PCR. Similar samples from Indian villages farther away from industrial areas, as well as fecal samples from Swedish study participants and river sediment from Sweden, were included for comparison. Fluoroquinolones were detected by MS/MS in well water and soil from all villages located within three km from industrially polluted waterways. Quinolone resistance genes were detected in 42% of well water, 7% of soil samples and in 100% and 18% of Indian and Swedish river sediments, respectively. High antibiotic concentrations in Indian sediment coincided with high abundances of qnr, whereas lower fluoroquinolone levels in well water and soil did not. We could not find support for an enrichment of qnr in fecal samples from people living in the fluoroquinolone-contaminated villages. However, as qnr was detected in 91% of all Indian fecal samples (24% of the Swedish) it suggests that the spread of qnr between people is currently a dominating transmission route.

  1. FIELD TEST OF AIR SPARGING COUPLED WITH SOIL VAPOR EXTRACTION

    EPA Science Inventory

    A controlled field study was designed and conducted to assess the performance of air sparging for remediation of petroleum fuel and solvent contamination in a shallow (3-m deep) groundwater aquifer. Sparging was performed in an insolation test cell (5 m by 3 m by 8-m deep). A soi...

  2. Fractal features of soil particle size distribution in layered sediments behind two check dams: Implications for the Loess Plateau, China

    NASA Astrophysics Data System (ADS)

    Wei, Xia; Li, Xungui; Wei, Ning

    2016-08-01

    The layered sediment deposited behind a check dam can provide useful information about soil erosion processes in the dam-controlled area. This study aims to evaluate the possible fractal nature of layered sediments behind check dams, assessing whether fractal dimension can serve as a feasible index for evaluating the impact of land use types on the area controlled by the check dam. Fractal dimension measurement was employed to analyze the features of soil particle size distribution (PSD) for different layered sediments of the Shipanmao and Zhangshan check dams in the Dalihe River Basin of the Loess Plateau, China. Results show that the predominant soil particle sizes of the sediment layers behind the Shipanmao and Zhangshan dams are silt-clay (< 0.05 mm) and fine sand (0.25-0.05 mm). The overall gradients of the trends for silt-clay and fine sand are 0.0622 (slight increase) and - 0.0618 (slight decrease), respectively, for Shipanmao, and - 0.8415 (decrease) and 0.8448 (increase), respectively, for Zhangshan. There are considerable differences in the PSDs among different layers, especially in the coarse and fine sand fractions. The coefficient of variation (CV) for the coarse sand fraction is highest, followed by the fine sand and the silt-clay size fractions. Larger soil particle sizes coincide with larger CV values. The fractal dimension (Dm) of the PSD ranges from 2.111 to 2.219, and 2.144 to 2.447 for Shipanmao and Zhangshan, respectively. The Dm values tend to increase and decrease for the layered sediments from top to bottom with some turning points. The turning points of Dm are related to the trends of the soil PSDs in the adjacent sediment layers. Although Dm has significant positive and negative correlations with the silt-clay and the fine sand size fractions, respectively, no correlation with the coarse sand fraction was observed. Soil PSD is a more dominant factor affecting Dm than the time lag between soil erosion and sediment deposition. Overall, Dm

  3. BOREAS RSS-17 Stem, Soil, and Air Temperature Data

    NASA Technical Reports Server (NTRS)

    Zimmerman, Reiner; McDonald, Kyle C.; Way, JoBea; Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS RSS-17 team collected several data sets in support of its research in monitoring and analyzing environmental and phenological states using radar data. This data set consists of tree bole and soil temperature measurements from various BOREAS flux tower sites. Temperatures were measured with thermistors implanted in the hydroconductive tissue of the trunks of several trees at each site and at various depths in the soil. Data were stored on a data logger at intervals of either 1 or 2 hours. The majority of the data were acquired between early 1994 and early 1995. The primary product of this data set is the diurnal stem temperature measurements acquired for selected trees at five BOREAS tower sites. The data are provided in tabular ASCII format. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  4. Mining-Related Sediment and Soil Contamination in a Large Superfund Site: Characterization, Habitat Implications, and Remediation

    NASA Astrophysics Data System (ADS)

    Juracek, K. E.; Drake, K. D.

    2016-10-01

    Historical mining activity (1850-1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

  5. Metal accumulation, biochemical response and yield of Indian mustard grown in soil amended with rural roadside pond sediment.

    PubMed

    Karak, Tanmoy; Bhattacharyya, Pradip; Kumar Paul, Ranjit; Das, D K

    2013-06-01

    This present study aims to discern the effect of roadside pond sediments on Brassica juncea (L.) Czern. (cv. Rohini) by examining heavy metal uptake by different parts of the plant and its influence on biochemical properties, biomass, yield and oil content in plant. Although the treated soils were clearly contaminated with heavy metals (HMs) after application of pond sediments and chemical fertilizers, but the metal content in mustard leaves and seeds are below the permissible limit of consumable food. HMs accumulation was proportionally lesser in grains than in shoots and roots. All the biochemical characteristics were significantly (p<0.05) responded to the pond sediments application as compared to the control. Increase in photosynthetic pigment was also observed during growing period while pond sediment was used as amendment. This study revealed that Brassica juncea is well adapted to tolerate and accumulate high quantities of HMs due to increased level of antioxidants (cysteine and ascorbic acid) in roots, shoots and leaves. Multivariate techniques like principal component analysis and cluster analysis (CA) were used as classification techniques. On the basis of factor loadings and principal component scores, different parameters were grouped based on their similarity or closeness, separately in leaves, roots and seeds. A very similar grouping was also obtained using CA. However, pond sediment did not thwart the enhancement of mustard yield and oil content. Therefore, pond sediment would be a valuable resource for mustard as an alternative soil amendment for nutrients, but long-term use may require the cessation to restrict HMs contamination in soils. PMID:23597677

  6. Mining-Related Sediment and Soil Contamination in a Large Superfund Site: Characterization, Habitat Implications, and Remediation.

    PubMed

    Juracek, K E; Drake, K D

    2016-10-01

    Historical mining activity (1850-1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

  7. Mining-Related Sediment and Soil Contamination in a Large Superfund Site: Characterization, Habitat Implications, and Remediation.

    PubMed

    Juracek, K E; Drake, K D

    2016-10-01

    Historical mining activity (1850-1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site. PMID:27357805

  8. Mining-related sediment and soil contamination in a large Superfund site: Characterization, habitat implications, and remediation

    USGS Publications Warehouse

    Juracek, Kyle E.; Drake, K. D.

    2016-01-01

    Historical mining activity (1850–1970) in the now inactive Tri-State Mining District provided an ongoing source of lead and zinc to the environment including the US Environmental Protection Agency Superfund site located in Cherokee County, southeast Kansas, USA. The resultant contamination adversely affected biota and caused human health problems and risks. Remediation in the Superfund site requires an understanding of the magnitude and extent of contamination. To provide some of the required information, a series of sediment and soil investigations were conducted in and near the Superfund site to characterize lead and zinc contamination in the aquatic and floodplain environments along the main-stem Spring River and its major tributaries. In the Superfund site, the most pronounced lead and zinc contamination, with concentrations that far exceed sediment quality guidelines associated with potential adverse biological effects, was measured for streambed sediments and floodplain soils located within or downstream from the most intensive mining-affected areas. Tributary streambeds and floodplains in affected areas are heavily contaminated with some sites having lead and zinc concentrations that are an order of magnitude (or more) greater than the sediment quality guidelines. For the main-stem Spring River, the streambed is contaminated but the floodplain is mostly uncontaminated. Measured lead and zinc concentrations in streambed sediments, lakebed sediments, and floodplain soils documented a persistence of the post-mining contamination on a decadal timescale. These results provide a basis for the prioritization, development, and implementation of plans to remediate contamination in the affected aquatic and floodplain environments within the Superfund site.

  9. Oil spill in the Rio de la Plata estuary, Argentina: 1. Biogeochemical assessment of waters, sediments, soils and biota.

    PubMed

    Colombo, J C; Barreda, A; Bilos, C; Cappelletti, N; Demichelis, S; Lombardi, P; Migoya, M C; Skorupka, C; Suárez, G

    2005-03-01

    Aliphatic (ALI) and aromatic (ARO) hydrocarbon concentrations, composition and sources were evaluated in waters, sediments, soils and biota to assess the impact of approximately 1000 tons of oil spilled in Rio de la Plata coastal waters. Total ALI levels ranged from 0.4-262 microg/l in waters, 0.01-87 microg/g in sediments, 5-39 microg/g in bivalves, 12-323 microg/g in macrophytes to 948-5187 microg/g in soils. ARO varied from non-detected 10 microg/l, 0.01-1.3 mug/g, 1.0-16 microg/g, 0.5-6.9 microg/g to 22-67 microg/g, respectively. Offshore (1, 5, 15 km) waters and sediments were little affected and contained low background hydrocarbon levels reflecting an effective wind-driven transport of the slick to the coast. Six months after the spill, coastal waters, sediments, soils and biota still presented very high levels exceeding baseline concentrations by 1-3 orders of magnitude. UCM/resolved aliphatic ratio showed a clear trend of increasing decay: coastal waters (3.3) < macrophytes (6.7) < soils (9.4) < offshore sediments (13) < coastal sediments (17) < clams (52). All environmental compartments consistently indicated that the most impacted area was the central sector close to Magdalena city, specially low-energy stream embouchures and bays which acted as efficient oil traps. The evaluation of hydrocarbon composition by principal component analysis indicated the predominance of biogenic (algae, vascular plant cuticular waxes), background anthropic, pyrogenic and diagenetic hydrocarbons, offshore and in non-impacted coastal sites. In contrast, polluted stations presented petrogenic signatures characterized by the abundance of isoprenoids, low molecular weight n-alkanes and methylated aromatics in different stages of alteration. The petrogenic/biogenic ratio ( n-C23) and petrogenic/pyrogenic relationship (methylated/unsubstitued PAH) discriminated the samples according to the different degree of impact. The following paper

  10. Empirical models based on the universal soil loss equation fail to predict sediment discharges from Chesapeake Bay catchments.

    PubMed

    Boomer, Kathleen B; Weller, Donald E; Jordan, Thomas E

    2008-01-01

    The Universal Soil Loss Equation (USLE) and its derivatives are widely used for identifying watersheds with a high potential for degrading stream water quality. We compared sediment yields estimated from regional application of the USLE, the automated revised RUSLE2, and five sediment delivery ratio algorithms to measured annual average sediment delivery in 78 catchments of the Chesapeake Bay watershed. We did the same comparisons for another 23 catchments monitored by the USGS. Predictions exceeded observed sediment yields by more than 100% and were highly correlated with USLE erosion predictions (Pearson r range, 0.73-0.92; p < 0.001). RUSLE2-erosion estimates were highly correlated with USLE estimates (r = 0.87; p < 001), so the method of implementing the USLE model did not change the results. In ranked comparisons between observed and predicted sediment yields, the models failed to identify catchments with higher yields (r range, -0.28-0.00; p > 0.14). In a multiple regression analysis, soil erodibility, log (stream flow), basin shape (topographic relief ratio), the square-root transformed proportion of forest, and occurrence in the Appalachian Plateau province explained 55% of the observed variance in measured suspended sediment loads, but the model performed poorly (r(2) = 0.06) at predicting loads in the 23 USGS watersheds not used in fitting the model. The use of USLE or multiple regression models to predict sediment yields is not advisable despite their present widespread application. Integrated watershed models based on the USLE may also be unsuitable for making management decisions.

  11. Soil erosion and sediment yield, a double barrel problem in South Africa's only large river network without a dam

    NASA Astrophysics Data System (ADS)

    Le Roux, Jay

    2016-04-01

    Soil erosion not only involves the loss of fertile topsoil but is also coupled with sedimentation of dams, a double barrel problem in semi-arid regions where water scarcity is frequent. Due to increasing water requirements in South Africa, the Department of Water and Sanitation is planning water resource development in the Mzimvubu River Catchment, which is the only large river network in the country without a dam. Two dams are planned including a large irrigation dam and a hydropower dam. However, previous soil erosion studies indicate that large parts of the catchment is severely eroded. Previous studies, nonetheless, used mapping and modelling techniques that represent only a selection of erosion processes and provide insufficient information about the sediment yield. This study maps and models the sediment yield comprehensively by means of two approaches over a five-year timeframe between 2007 and 2012. Sediment yield contribution from sheet-rill erosion was modelled with ArcSWAT (a graphical user interface for SWAT in a GIS), whereas gully erosion contributions were estimated using time-series mapping with SPOT 5 imagery followed by gully-derived sediment yield modelling in a GIS. Integration of the sheet-rill and gully results produced a total sediment yield map, with an average of 5 300 t km-2 y-1. Importantly, the annual average sediment yield of the areas where the irrigation dam and hydropower dam will be built is around 20 000 t km-2 y-1. Without catchment rehabilitation, the life expectancy of the irrigation dam and hydropower dam could be 50 and 40 years respectively.

  12. Air sparging/high vacuum extraction to remove chlorinated solvents in groundwater and soil

    SciTech Connect

    Phelan, J.M.; Gilliat, M.D.

    1998-11-01

    An air sparging and high vacuum extraction was installed as an alternative to a containment pump and treat system to reduce the long-term remediation schedule. The site is located at the DOE Mound facility in Miamisburg, Ohio, just south of Dayton. The air sparging system consists of 23 wells interspersed between 17 soil vapor extraction wells. The SVE system has extracted about 1,500 lbs of VOCs in five months. The air sparging system operated for about 6 weeks before shutdown due to suspected biochemical fouling. Technical data are presented on the operating characteristics of the system.

  13. Distinct effects of moisture and air contents on acoustic properties of sandy soil.

    PubMed

    Oshima, Takuya; Hiraguri, Yasuhiro; Okuzono, Takeshi

    2015-09-01

    Knowledge of distinct effects of moisture content and air volume on acoustic properties of soil is sought to predict the influence of human activities such as cultivation on acoustic propagation outdoors. This work used an impedance tube with the two-thickness method to investigate such effects. For a constant moisture weight percentage, the magnitude of the characteristic impedance became smaller and the absorption coefficient became higher with increase of the air space ratio. For a constant air space ratio, the absorption coefficient became larger and the magnitude of the propagation constant became smaller with increasing moisture weight percentage. PMID:26428823

  14. Influence of Temperature, Relative Humidity, and Soil Properties on the Soil-Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models.

    PubMed

    Davie-Martin, Cleo L; Hageman, Kimberly J; Chin, Yu-Ping; Rougé, Valentin; Fujita, Yuki

    2015-09-01

    Soil-air partition coefficient (Ksoil-air) values are often employed to investigate the fate of organic contaminants in soils; however, these values have not been measured for many compounds of interest, including semivolatile current-use pesticides. Moreover, predictive equations for estimating Ksoil-air values for pesticides (other than the organochlorine pesticides) have not been robustly developed, due to a lack of measured data. In this work, a solid-phase fugacity meter was used to measure the Ksoil-air values of 22 semivolatile current- and historic-use pesticides and their degradation products. Ksoil-air values were determined for two soils (semiarid and volcanic) under a range of environmentally relevant temperature (10-30 °C) and relative humidity (30-100%) conditions, such that 943 Ksoil-air measurements were made. Measured values were used to derive a predictive equation for pesticide Ksoil-air values based on temperature, relative humidity, soil organic carbon content, and pesticide-specific octanol-air partition coefficients. Pesticide volatilization losses from soil, calculated with the newly derived Ksoil-air predictive equation and a previously described pesticide volatilization model, were compared to previous results and showed that the choice of Ksoil-air predictive equation mainly affected the more-volatile pesticides and that the way in which relative humidity was accounted for was the most critical difference.

  15. Influence of Temperature, Relative Humidity, and Soil Properties on the Soil-Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models.

    PubMed

    Davie-Martin, Cleo L; Hageman, Kimberly J; Chin, Yu-Ping; Rougé, Valentin; Fujita, Yuki

    2015-09-01

    Soil-air partition coefficient (Ksoil-air) values are often employed to investigate the fate of organic contaminants in soils; however, these values have not been measured for many compounds of interest, including semivolatile current-use pesticides. Moreover, predictive equations for estimating Ksoil-air values for pesticides (other than the organochlorine pesticides) have not been robustly developed, due to a lack of measured data. In this work, a solid-phase fugacity meter was used to measure the Ksoil-air values of 22 semivolatile current- and historic-use pesticides and their degradation products. Ksoil-air values were determined for two soils (semiarid and volcanic) under a range of environmentally relevant temperature (10-30 °C) and relative humidity (30-100%) conditions, such that 943 Ksoil-air measurements were made. Measured values were used to derive a predictive equation for pesticide Ksoil-air values based on temperature, relative humidity, soil organic carbon content, and pesticide-specific octanol-air partition coefficients. Pesticide volatilization losses from soil, calculated with the newly derived Ksoil-air predictive equation and a previously described pesticide volatilization model, were compared to previous results and showed that the choice of Ksoil-air predictive equation mainly affected the more-volatile pesticides and that the way in which relative humidity was accounted for was the most critical difference. PMID:26258946

  16. Grain size and hydrodynamic sorting controls on the composition of basaltic sediments: Implications for interpreting martian soils

    NASA Astrophysics Data System (ADS)

    Fedo, Christopher M.; McGlynn, Ian O.; McSween, Harry Y.

    2015-08-01

    Impact shattering of bedrock and wind-driven sorting have been identified as primary processes modifying the size, shape, and roundness of basalt-derived sediments at the Spirit rover landing site in Gusev Crater, Mars. We experimentally explore how physical sorting can cause significant compositional modification of sediment relative to bedrock in the absence of chemical weathering. Two basalt samples, chosen to provide a range of source rock compositions and textures, were crushed and sieved. We quantify variations in sediment mineral proportions as a function of grain size, as well as accompanying changes in major- and trace-element geochemistry. Redistribution of phenocrysts imposes the primary compositional control on basalt-derived sediments, although minor mineral fractionations affect trace-element concentrations. Olivine accumulation pairs with increasing MgO, Fe2O3(T), Ni, and Co, and Al2O3 depletion. The observed chemical changes in physically sorted sediments in our experiments mimic those measured in martian soils. Aeolian transport models demonstrate that sorting of mineral components of basalts under martian conditions is likely. Given the potential for sorting by winds on Mars we argue that sorting must be considered, in addition to chemical weathering, when interpreting the geochemical changes in martian sediments.

  17. Air pollution: Household soiling and consumer welfare losses

    USGS Publications Warehouse

    Watson, W.D.; Jaksch, J.A.

    1982-01-01

    This paper uses demand and supply functions for cleanliness to estimate household benefits from reduced particulate matter soiling. A demand curve for household cleanliness is estimated, based upon the assumption that households prefer more cleanliness to less. Empirical coefficients, related to particulate pollution levels, for shifting the cleanliness supply curve, are taken from available studies. Consumer welfare gains, aggregated across 123 SMSAs, from achieving the Federal primary particulate standard, are estimated to range from $0.9 to $3.2 million per year (1971 dollars). ?? 1982.

  18. MEASUREMENT OF EFFECTIVE AIR DIFFUSION COEFFICIENTS FOR TRICHLOROETHENE IN UNDISTURBED SOIL CORES. (R826162)

    EPA Science Inventory

    Abstract

    In this study, we measure effective diffusion coefficients for trichloroethene in undisturbed soil samples taken from Picatinny Arsenal, New Jersey. The measured effective diffusion coefficients ranged from 0.0053 to 0.0609 cm2/s over a range of air...

  19. Dry deposition and soil-air gas exchange of polychlorinated biphenyls (PCBs) in an industrial area.

    PubMed

    Bozlaker, Ayse; Odabasi, Mustafa; Muezzinoglu, Aysen

    2008-12-01

    Ambient air and dry deposition, and soil samples were collected at the Aliaga industrial site in Izmir, Turkey. Atmospheric total (particle+gas) Sigma(41)-PCB concentrations were higher in summer (3370+/-1617 pg m(-3), average+SD) than in winter (1164+/-618 pg m(-3)), probably due to increased volatilization with temperature. Average particulate Sigma(41)-PCBs dry deposition fluxes were 349+/-183 and 469+/-328 ng m(-2) day(-1) in summer and winter, respectively. Overall average particulate deposition velocity was 5.5+/-3.5 cm s(-1). The spatial distribution of Sigma(41)-PCB soil concentrations (n=48) showed that the iron-steel plants, ship dismantling facilities, refinery and petrochemicals complex are the major sources in the area. Calculated air-soil exchange fluxes indicated that the contaminated soil is a secondary source to the atmosphere for lighter PCBs and as a sink for heavier ones. Comparable magnitude of gas exchange and dry particle deposition fluxes indicated that both mechanisms are equally important for PCB movement between air and soil in Aliaga.

  20. Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus).

    PubMed

    Mikes, Ondrej; Cupr, Pavel; Trapp, Stefan; Klanova, Jana

    2009-02-01

    Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for beta-hexachlorocyclohexane. Bioconcentration factor (BCF, defined as a ratio between the contaminant concentration in the plant tissue and concentration in soil) was determined for roots, edible bulbs and shoots. Root BCF values were constant and not correlated to log K(OW). A negative correlation between BCF and log K(OW) was found for edible bulbs. Shoot BCF values were rather constant and varied between 0.01 and 0.22. Resuspended soil particles may facilitate the transport of chemicals from soil to shoots. Elevated POP concentrations found in shoots of radishes grown in the control plot support the hypothesis that the uptake from air was more significant for shoots than the one from soil. The uptake of POPs from air was within the range of theoretical values predicted from log K(OA).

  1. Modelling the initial structure dynamics of soil and sediment exemplified for a constructed hydrological catchment

    NASA Astrophysics Data System (ADS)

    Maurer, Thomas; Schneider, Anna; Gerke, Horst H.

    2014-05-01

    depending on initial structures, and (ii) relate the simulated structural development to the (observed) hydrological behaviour. For the description of the initial development, already established "structure-generating" models were chosen for the simulation of erosion and deposition structures, crusts and vegetation. The OpenMI software interface was chosen to provide parameter exchange between the models. The impact of the structural development on the hydrological behaviour of the catchment will be evaluated by modelling water flow with HYDRUS 2D/3D. For that purpose, an approach to estimate 3D distributions of soil hydraulic parameter from generated sediment properties using adapted pedotransfer functions was already developed. Model results can be validated by comparing them to measured discharges from the catchment. By comparing different scenarios, the impact of spatial structures on flow behaviour can be analysed. Results may be transferred to similar environments by identifying generalizable eco-hydrological compartments ('Process Domains') from model data.

  2. Technical development of geomicrobiological fixation of heavy metals in soils and sediments by biosorption and bioreduction -case histories in Korea

    NASA Astrophysics Data System (ADS)

    Lee, Sung-Eun; Kim, Sang-Ho; Lee, Jong-Un; Chon, Hyo-Taek

    2013-04-01

    Conventional physicochemical technologies to remediate heavy metals-contaminated soil have many problems such as low efficiency, high cost and occurrence of byproducts. Recently biological stabilization technology is getting more and more attention. The advantage of this technology is that toxic metals can be stabilized for long time with no necessity of retreatment. The objective of this research is to develop geomicrobiological stabilization technologies of heavy metals by biosorption and oxidation/reduction in contaminated soil and sediment. Geochemical characteristics of heavy metals such as concentration and speciation in contaminated soil were investigated. Environmental conditions for effective biosorption were also investigated. It was successful to form biofilm in soil. Biofilm had great heavy metal biosorption capacity. Bioreduction efficiency of hexavalent chromium by indigenous bacteria was evaluated in various conditions.. From now on, it is necessary to prove applicability of this technologies to contaminated sites and to establish highly effective, low-cost and easy bioremediation technology.

  3. Understanding the Impact of Charcoal Inputs to Soils and Sediments on Conventional Geochemical Markers

    NASA Astrophysics Data System (ADS)

    Kuo, L.; Louchouarn, P.; Herbert, B.

    2008-12-01

    increasing combustion temperature, internal phenol ratios (S/V and C/V) show a two-stage change with an initial increase at low temperatures followed by marked and rapid decreases when temperatures reach 200- 250°C. The acid/aldehyde ratios of vanillyl phenols ((Ad/Al)v) and syringyl phenols ((Ad/Al)s) all increase with increasing combustion temperature and duration and reach a maximum values at 300- 350°C, regardless plant species. The highly elevated acid/aldehyde ratios reached in some cases exceed the reported values of humic and fulvic acids extracted from soils and sediments. We applied these empirical data in mixing models to estimate the potential effects of charcoal inputs on the observed lignin signatures in environmental mixtures. The shifts in lignin signatures are strongly influenced both by the characteristics of the charcoal incorporated and the proportion of charcoal in the mixture. We validated our observations with two sets of environmental samples, including soils from control burning sites, and a sediment core from a wetland with evidence of charcoal inputs, showing that the presences of charcoals do alter the observed lignin signals in these samples. Such a thermal "interference" on lignin parameters should thus be considered in environmental mixtures with recognized char input.

  4. Regional Geochemical Results from Analyses of Stream-Water, Stream-Sediment, Soil, Soil-Water, Bedrock, and Vegetation Samples, Tangle Lakes District, Alaska

    USGS Publications Warehouse

    Wang, Bronwen; Gough, L.P.; Wanty, R.B.; Lee, G.K.; Vohden, James; O'Neill, J. M.; Kerin, L.J.

    2008-01-01

    We report chemical analyses of stream-water, stream-sediment, soil, soil-water, bedrock, and vegetation samples collected from the headwaters of the Delta River (Tangle Lakes District, Mount Hayes 1:250,000-scale quadrangle) in east-central Alaska for the period June 20-25, 2006. Additionally, we present mineralogic analyses of stream sediment, concentrated by panning. The study area includes the southwestward extent of the Bureau of Land Management (BLM) Delta River Mining District (Bittenbender and others, 2007), including parts of the Delta River Archeological District, and encompasses an area of about 500 km2(approximately bordered by the Denali Highway to the south, near Round Tangle Lake, northward to the foothills of the Alaska Range (fig. 1). The primary focus of this study was the chemical characterization of native materials, especially surface-water and sediment samples, of first-order streams from the headwaters of the Delta River. The impetus for this work was the need, expressed by the Alaska Department of Natural Resources (ADNR), for an inventory of geochemical and hydrogeochemical baseline information about the Delta River Mining District. This information is needed because of a major upturn in exploration, drilling, and general mineral-resources assessments in the region since the late 1990s. Currently, the study area, called the 'MAN Project' area is being explored by Pure Nickel, Inc. (http://www.purenickel.com/s/MAN_Alaska.asp), and includes both Cu-Au-Ag and Ni-Cu-PGE (Pt-Pd-Au-Ag) mining claims. Geochemical data on surface-water, stream-sediment, soil, soil-water, grayleaf willow (Salix glauca L.), and limited bedrock samples are provided along with the analytical methodologies used and panned-concentrate mineralogy. We are releasing the data at this time with only minimal interpretation.

  5. Mercury in soil gas and air--A potential tool in mineral exploration

    USGS Publications Warehouse

    McCarthy, Joseph Howard; Vaughn, W.W.; Learned, R.E.; Meuschke, J.L.

    1969-01-01

    The mercury content in soil gas and in the atmosphere was measured in several mining districts to test the possibility that the mercury content in the atmosphere is higher over ore deposits than over barren ground. At Cortez, Nev., the distribution of anorhalous amounts of mercury in the air collected at ground level (soil gas) correlates well with the distribution of gold-bearing rocks that are covered by as much as 100 feet of gravel. The mercury content in the atmosphere collected at an altitude of 200 feet by an aircraft was 20 times background over a mercury posit and 10 times background over two porphyry copper deposits. Measurement of mercury in soil gas and air may prove to be a valuable exploration tool.

  6. Caesium-137 in Southeast Asia: Is there enough left for soil erosion and sediment redistribution studies?

    NASA Astrophysics Data System (ADS)

    Furuichi, Takahisa; Wasson, Robert J.

    2013-11-01

    Low reference inventories of the fallout radionuclide 137Cs in low latitudes may limit its present and future application for studies of soil erosion and sediment redistribution in Southeast Asia. 137Cs reference inventories and concentrations in surface materials measured in nine and five areas, respectively, across Southeast Asia are here reported and reviewed. The compiled reference inventories decrease from north to south. Three global estimates of 137Cs total fallout are also reviewed and compared to the measured data while taking into account factors that affect the fallout estimates and the reference inventory. The results are presented as a schematic regional distribution map of 137Cs reference inventories for the year 2012. A relationship between a reference inventory and topsoil concentration is also provided. The measured 137Cs concentrations suggest that a minimum detectable activity (MDA) less than 0.5 Bq/kg is required for detection of 137Cs activity in topsoils in the lowest reference inventory areas. This sensitivity should allow, at present, 137Cs to be a useful tool for analysis of soil erosion in Southeast Asia, should also be a useful chronometer, and will be a useful tracer at least where the reference inventory is more than 500-600 Bq/m2. This level of MDA has been demonstrated in previous studies to be achievable by gamma-ray spectrometry using non-destructive sample treatment. As the nuclide decays, sufficient will remain to be useful until the middle of this century in most areas in Peninsular Malaysia and southern maritime Southeast Asia, and a few decades more in the rest of the region.

  7. Reducing compaction effort and incorporating air permeability in Proctor testing for design of urban green spaces on cohesive soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is well established that compaction negatively affects agronomic productivity, that air permeability is a sensitive measure of the degree of soil compaction and therefore a good indicator of soil productivity impairment from compaction. Cohesive soils in urban settings are often heavily compacted...

  8. Seasonal dynamics of trace elements in tidal salt marsh soils as affected by the flow-sediment regulation regime.

    PubMed

    Bai, Junhong; Xiao, Rong; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing; Reddy, K Ramesh

    2014-01-01

    Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering. PMID:25216278

  9. Seasonal dynamics of trace elements in tidal salt marsh soils as affected by the flow-sediment regulation regime.

    PubMed

    Bai, Junhong; Xiao, Rong; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing; Reddy, K Ramesh

    2014-01-01

    Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering.

  10. Seasonal Dynamics of Trace Elements in Tidal Salt Marsh Soils as Affected by the Flow-Sediment Regulation Regime

    PubMed Central

    Bai, Junhong; Xiao, Rong; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing; Reddy, K. Ramesh

    2014-01-01

    Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering. PMID:25216278

  11. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign. PMID:26476769

  12. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign.

  13. [Effects of air temperature and soil moisture on flavonoids accumulation in Ginkgo biloba leaves].

    PubMed

    Wang, Gui-Bin; Guo, Xu-Qin; Chang, Li; Cao, Fu-Liang

    2013-11-01

    Taking the 2-year old Ginkgo biloba seedlings as test materials, a pot experiment was conducted in an artificial climate chamber to study the effects of air temperature and soil moisture on the flavonoids accumulation in leaves. Three levels of air temperature (15/5 degrees C, 25/15 degrees C, and 35/25 degrees C day/night) and three levels of soil moisture (55%-60%, 40%-45%, and 30%-35% of field capacity) were installed, yielding nine temperature-soil moisture combinations. Under the three levels of soil moisture, the quercetin, kaempferol, isorhamnetin, and total flavonoids contents in the leaves were higher at 15/5 degrees C than at 25/15 degrees C and 35/25 degrees C. Soil moisture had minor effects on the flavonoids accumulation. The leaf kaempferol content was the highest, followed by quercetin and isorhamnetin. The total flavonoids yield per plant at 35/25 degrees C was higher than that at 15/5 degrees C and 25/15 degrees C. It was suggested that to adopt appropriate soil covering and watering before harvesting to decrease the ambient temperature could benefit the enhancement of leaf flavonoids content and the improvement of per unit area flavonoids production in G. biloba leaf-harvesting plantation.

  14. Determination of radioactive elements and heavy metals in sediments and soil from domestic water sources in northern peninsular Malaysia.

    PubMed

    Muhammad, Bashir G; Jaafar, Mohammad Suhaimi; Abdul Rahman, Azhar; Ingawa, Farouk Abdulrasheed

    2012-08-01

    Soil serves as a major reservoir for contaminants as it posseses an ability to bind various chemicals together. To safeguard the members of the public from an unwanted exposure, studies were conducted on the sediments and soil from water bodies that form the major sources of domestic water supply in northern peninsular Malaysia for their trace element concentration levels. Neutron Activation Analysis, using Nigeria Research Reactor-1 (NIRR-1) located at the Centre for Energy Research and Training, Zaria, Nigeria was employed as the analytical tool. The elements identified in major quantities include Na, K, and Fe while As, Br, Cr, U, Th, Eu, Cs, Co, La, Sm, Yb, Sc, Zn, Rb, Ba, Lu, Hf, Ta, and Sb were also identified in trace quantities. Gamma spectroscopy was also employed to analyze some soil samples from the same area. The results indicated safe levels in terms of the radium equivalent activity, external hazard index as well as the mean external exposure dose rates from the soil. The overall screening of the domestic water sources with relatively high heavy metals concentration values in sediments and high activity concentration values in soil is strongly recommended as their accumulation overtime as a consequence of leaching into the water may be of health concern to the members of the public. PMID:21901308

  15. A feasibility study of modeling pedogenic carbonates in soils and sediments at the US Department of Energy's Hanford Site

    SciTech Connect

    Hunter, C.R.; Busacca, A.J. )

    1990-09-01

    This study was conducted for Pacific Northwest Laboratory by Washington State University in support of the US Department of Energy's Protective Barrier and Warning Marker System Development Program. The objective of this study was to determine the feasibility of deriving information about past water movement patterns from Holocene-age soils in the Hanford region, and using mathematical simulation modeling of pedogenic carbonate accumulations in layered sediments as a performance assessment tool for protective barrier development. The pedogenic carbonate models would serve two purposes in barrier performance assessment: to reconstruct Holocene water movement from the distribution of carbonates in layered sediments as an analog of future water movement in protective barriers, and to simulate the feedback effect of carbonate accumulation on soil hydraulic properties and unsaturated recharge in proposed protective barrier designs. The study progressed in three phases. The first phase was a review and interpretation of current literature on pedogenic indicators of water movement. The review focused on pedogenic and lithogenic processes that drive carbonate accumulation in arid land soils and simulation models linking carbonate distribution to soil hydraulic properties, soil water balance, and climate. The second phase of the feasibility study identified issues and limitations associated with applying or modifying existing computer simulation codes or developing a new code. Finally, the utility of proceeding with the project was determined based on an evaluation of issues and limitations in relation to barrier performance criteria. 101 refs., 4 figs.

  16. Determination of radioactive elements and heavy metals in sediments and soil from domestic water sources in northern peninsular Malaysia.

    PubMed

    Muhammad, Bashir G; Jaafar, Mohammad Suhaimi; Abdul Rahman, Azhar; Ingawa, Farouk Abdulrasheed

    2012-08-01

    Soil serves as a major reservoir for contaminants as it posseses an ability to bind various chemicals together. To safeguard the members of the public from an unwanted exposure, studies were conducted on the sediments and soil from water bodies that form the major sources of domestic water supply in northern peninsular Malaysia for their trace element concentration levels. Neutron Activation Analysis, using Nigeria Research Reactor-1 (NIRR-1) located at the Centre for Energy Research and Training, Zaria, Nigeria was employed as the analytical tool. The elements identified in major quantities include Na, K, and Fe while As, Br, Cr, U, Th, Eu, Cs, Co, La, Sm, Yb, Sc, Zn, Rb, Ba, Lu, Hf, Ta, and Sb were also identified in trace quantities. Gamma spectroscopy was also employed to analyze some soil samples from the same area. The results indicated safe levels in terms of the radium equivalent activity, external hazard index as well as the mean external exposure dose rates from the soil. The overall screening of the domestic water sources with relatively high heavy metals concentration values in sediments and high activity concentration values in soil is strongly recommended as their accumulation overtime as a consequence of leaching into the water may be of health concern to the members of the public.

  17. Forensic differentiation of biogenic organic compounds from petroleum hydrocarbons in biogenic and petrogenic compounds cross-contaminated soils and sediments.

    PubMed

    Wang, Zhendi; Yang, C; Kelly-Hooper, F; Hollebone, B P; Peng, X; Brown, C E; Landriault, M; Sun, J; Yang, Z

    2009-02-13

    "Total petroleum hydrocarbons" (TPHs) or "petroleum hydrocarbons" (PHCs) are one of the most widespread soil pollutants in Canada, North America, and worldwide. Clean-up of PHC-contaminated soils and sediments costs the Canadian economy hundreds of million of dollars annually. Much of this activity is driven by the need to meet regulated levels of PHC in soil. These PHC values are legally required to be assessed using standard methods. The method most commonly used in Canada, specified by the Canadian Council of Ministers of the Environment (CCME), measures the total hydrocarbon concentrations in a soil by carbon range (Fraction 1: C(6)-C(10); Fraction 2: C(10)-C(16), Fraction 3: C(16)-C(34): and Fraction 4: C(34)+). Using the CCME method, all of the materials extractible by a mixture of 1:1 hexane:acetone are considered to be petroleum hydrocarbon contaminants. Many hydrocarbon compounds and other extractible materials in soil, however, may originate from non-petroleum sources. Biogenic organic compounds (BOCs) is a general term used to describe a mixture of organic compounds, including alkanes, sterols and sterones, fatty acids and fatty alcohols, and waxes and wax esters, biosynthesized by living organisms. BOCs are also produced during the early stages of diagenesis in recent aquatic sediments. BOC sources could include vascular plants, algae, bacteria and animals. Plants and algae produce BOCs as protective wax coating that are released back into the sediment at the end of their life cycle. BOCs are natural components of thriving plant communities. Many solvent-extraction methods for assessing soil hydrocarbons, however, such as the CCME method, do not differentiate PHCs from BOCs. The naturally occurring organics present in soils and wet sediments can be easily misidentified and quantified as regulated PHCs during analysis using such methods. In some cases, biogenic interferences can exceed regulatory levels, resulting in remediation of petroleum impacts that

  18. Decomposition of heavy metal contaminated nettles (Urtica dioica L.) in soils subjected to heavy metal pollution by river sediments.

    PubMed

    Khan, Khalid Saifullah; Joergensen, Rainer Georg

    2006-11-01

    Two incubation experiments were conducted to evaluate differences in the microbial use of non-contaminated and heavy metal contaminated nettle (Urtica dioica L.) shoot residues in three soils subjected to heavy metal pollution (Zn, Pb, Cu, and Cd) by river sediments. The microbial use of shoot residues was monitored by changes in microbial biomass C, biomass N, biomass P, ergosterol, N mineralisation, CO(2) production and O(2) consumption rates. Microbial biomass C, N, and P were estimated by fumigation extraction. In the non-amended soils, the mean microbial biomass C to soil organic C ratio decreased from 2.3% in the low metal soil to 1.1% in the high metal soils. In the 42-d incubation experiment, the addition of 2% nettle residues resulted in markedly increased contents of microbial biomass P (+240%), biomass C (+270%), biomass N (+310%), and ergosterol (+360%). The relative increase in the four microbial properties was similar for the three soils and did not show any clear heavy metal effect. The contents of microbial biomass C, N and P and ergosterol contents declined approximately by 30% during the incubation as in the non-amended soils. The ratios microbial biomass C to N, microbial biomass C to P, and ergosterol to microbial biomass C remained constant at 5.2, 26, and 0.5%, respectively. In the 6-d incubation experiment, the respiratory quotient CO(2)/O(2) increased from 0.74 in the low metal soil to 1.58 in the high metal soil in the non-amended soils. In the treatments amended with 4% nettle residues, the respiratory quotient was constant at 1.13, without any effects of the three soils or the two nettle treatments. Contaminated nettle residues led generally to significantly lower N mineralisation, CO(2) production and O(2) consumption rates than non-contaminated nettle residues. However, the absolute differences were small. PMID:16677685

  19. A 1400 year environmental magnetic record from varved sediments of Lake Xiaolongwan (Northeast China) reflecting natural and anthropogenic soil erosion

    NASA Astrophysics Data System (ADS)

    Su, Youliang; Chu, Guoqiang; Liu, Qingsong; Jiang, Zhaoxia; Gao, Xing; Haberzettl, Torsten

    2015-09-01

    Lake sediments can provide high-quality information about human activities. In this study, we investigate a sediment core from Lake Xiaolongwan using magnetic and geochemical methods. The dominant magnetic minerals of this sediment core are stable single domain (SSD) and superparamagnetic (SP) magnetite particles. The increasing amount of SP particles reflected by the rise of magnetic susceptibility and frequency dependent magnetic susceptibility since AD 1500 can be attributed to an increasing influx in pedogenic soil, which is related to a regional-scale increase in the intensity of human activity in Northeastern China. This extends the timing of human activities, which is independent from climate changes and its effects on local ecosystems in Northeastern China significantly.

  20. Mercury concentrations and distribution in soil, water, mine waste leachates, and air in and around mercury mines in the Big Bend region, Texas, USA.

    PubMed

    Gray, John E; Theodorakos, Peter M; Fey, David L; Krabbenhoft, David P

    2015-02-01

    Samples of soil, water, mine waste leachates, soil gas, and air were collected from areas mined for mercury (Hg) and baseline sites in the Big Bend area, Texas, to evaluate potential Hg contamination in the region. Soil samples collected within 300 m of an inactive Hg mine contained elevated Hg concentrations (3.8-11 µg/g), which were considerably higher than Hg in soil collected from baseline sites (0.03-0.05 µg/g) distal (as much as 24 km) from mines. Only three soil samples collected within 300 m of the mine exceeded the probable effect concentration for Hg of 1.06 µg/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of Hg in mine water runoff (7.9-14 ng/L) were generally higher than those found in springs and wells (0.05-3.1 ng/L), baseline streams (1.1-9.7 ng/L), and sources of drinking water (0.63-9.1 ng/L) collected in the Big Bend region. Concentrations of Hg in all water samples collected in this study were considerably below the 2,000 ng/L drinking water Hg guideline and the 770 ng/L guideline recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic wildlife from chronic effects of Hg. Concentrations of Hg in water leachates obtained from leaching of mine wastes varied widely from <0.001 to 760 µg of Hg in leachate/g of sample leached, but only one leachate exceeded the USEPA Hg industrial soil screening level of 31 µg/g. Concentrations of Hg in soil gas collected at mined sites (690-82,000 ng/m(3)) were highly elevated compared to soil gas collected from baseline sites (1.2-77 ng/m(3)). However, air collected from mined areas at a height of 2 m above the ground surface contained concentrations of Hg (4.9-64 ng/m(3)) that were considerably lower than Hg in soil gas from the mined areas. Although concentrations of Hg emitted from mine-contaminated soils and mine wastes were elevated, persistent wind in southwest Texas disperses Hg in the air within a few meters of the

  1. Mercury concentrations and distribution in soil, water, mine waste leachates, and air in and around mercury mines in the Big Bend region, Texas, USA.

    PubMed

    Gray, John E; Theodorakos, Peter M; Fey, David L; Krabbenhoft, David P

    2015-02-01

    Samples of soil, water, mine waste leachates, soil gas, and air were collected from areas mined for mercury (Hg) and baseline sites in the Big Bend area, Texas, to evaluate potential Hg contamination in the region. Soil samples collected within 300 m of an inactive Hg mine contained elevated Hg concentrations (3.8-11 µg/g), which were considerably higher than Hg in soil collected from baseline sites (0.03-0.05 µg/g) distal (as much as 24 km) from mines. Only three soil samples collected within 300 m of the mine exceeded the probable effect concentration for Hg of 1.06 µg/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of Hg in mine water runoff (7.9-14 ng/L) were generally higher than those found in springs and wells (0.05-3.1 ng/L), baseline streams (1.1-9.7 ng/L), and sources of drinking water (0.63-9.1 ng/L) collected in the Big Bend region. Concentrations of Hg in all water samples collected in this study were considerably below the 2,000 ng/L drinking water Hg guideline and the 770 ng/L guideline recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic wildlife from chronic effects of Hg. Concentrations of Hg in water leachates obtained from leaching of mine wastes varied widely from <0.001 to 760 µg of Hg in leachate/g of sample leached, but only one leachate exceeded the USEPA Hg industrial soil screening level of 31 µg/g. Concentrations of Hg in soil gas collected at mined sites (690-82,000 ng/m(3)) were highly elevated compared to soil gas collected from baseline sites (1.2-77 ng/m(3)). However, air collected from mined areas at a height of 2 m above the ground surface contained concentrations of Hg (4.9-64 ng/m(3)) that were considerably lower than Hg in soil gas from the mined areas. Although concentrations of Hg emitted from mine-contaminated soils and mine wastes were elevated, persistent wind in southwest Texas disperses Hg in the air within a few meters of the

  2. Mercury concentrations and distribution in soil, water, mine waste leachates, and air in and around mercury mines in the Big Bend region, Texas, USA

    USGS Publications Warehouse

    Gray, John E.; Theodorakos, Peter M.; Fey, David L.; Krabbenhoft, David P.

    2015-01-01

    Samples of soil, water, mine waste leachates, soil gas, and air were collected from areas mined for mercury (Hg) and baseline sites in the Big Bend area, Texas, to evaluate potential Hg contamination in the region. Soil samples collected within 300 m of an inactive Hg mine contained elevated Hg concentrations (3.8–11 µg/g), which were considerably higher than Hg in soil collected from baseline sites (0.03–0.05 µg/g) distal (as much as 24 km) from mines. Only three soil samples collected within 300 m of the mine exceeded the probable effect concentration for Hg of 1.06 µg/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of Hg in mine water runoff (7.9–14 ng/L) were generally higher than those found in springs and wells (0.05–3.1 ng/L), baseline streams (1.1–9.7 ng/L), and sources of drinking water (0.63–9.1 ng/L) collected in the Big Bend region. Concentrations of Hg in all water samples collected in this study were considerably below the 2,000 ng/L drinking water Hg guideline and the 770 ng/L guideline recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic wildlife from chronic effects of Hg. Concentrations of Hg in water leachates obtained from leaching of mine wastes varied widely from <0.001 to 760 µg of Hg in leachate/g of sample leached, but only one leachate exceeded the USEPA Hg industrial soil screening level of 31 µg/g. Concentrations of Hg in soil gas collected at mined sites (690–82,000 ng/m3) were highly elevated compared to soil gas collected from baseline sites (1.2–77 ng/m3). However, air collected from mined areas at a height of 2 m above the ground surface contained concentrations of Hg (4.9–64 ng/m3) that were considerably lower than Hg in soil gas from the mined areas. Although concentrations of Hg emitted from mine-contaminated soils and mine wastes were elevated, persistent wind in southwest Texas disperses Hg in the air

  3. DEMONSTRATION AND QUALITY ASSURANCE PROJECT PLAN TECHNOLOGIES FOR THE MONITORING AND MEASUREMENT OF DIOXIN AND DIOXIN-LIKE COMPOUNDS IN SOIL AND SEDIMENT

    EPA Science Inventory

    The demonstration of technologies for determining the presence of dioxin in soil and sediment is being conducted under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in Saginaw, Michigan, at Green Point Environmental Learning Center fr...

  4. TECHNOLOGIES FOR MONITORING AND MEASUREMENT OF DIUOXIN AND DIOXIN-LIKE COMPOUNDS IN SOIL AND SEDIMENT. ABRAXIS LLC COPLANAR PCB ELISA KIT

    EPA Science Inventory

    A demonstration of technologies for determining the presence of dioxin and dioxin-like compounds in soil and sediment was conducted under EPA's Superfund Innovative Technology Evaluation Program in Saginaw, Michigan in April 2004. This report describes the performance evaluation ...

  5. Assumptions and challenges in the use of fallout beryllium-7 as a soil and sediment tracer in river basins

    NASA Astrophysics Data System (ADS)

    Taylor, A.; Blake, W. H.; Smith, H. G.; Mabit, L.; Keith-Roach, M. J.

    2013-11-01

    This contribution reviews research surrounding the assumptions that underpin the use of beryllium-7 (7Be) as a soil and sediment tracer in river basins. As a cosmogenic radionuclide, the constant natural production of 7Be and fallout via precipitation, coupled with its ability to bind to soil and sediment particles provides the basis for its application as a conservative soil and sediment tracer. Consequently, 7Be has been extensively employed as a tracer across a range of spatial and temporal (event to seasonal) scales. The short half-life of 7Be (53.3 days) lends itself to tracing sediment dynamics over short time periods, thus, providing complementary data to medium-term estimates derived from longer lived radionuclides such as caesium-137 (137Cs). This short half-life could provide a major advantage when considering the potential for 7Be to document recent effects of climate or land use change upon soil redistribution, with the latter having particular relevance for assessing the effectiveness of mitigating strategies within a catchment-wide approach to management. Although 7Be has been widely applied as a tracer to date, application is still in its infancy and there remains a lack of knowledge in relation to the assumptions for its use as a tracer. Specifically, our findings suggest that there are crucial information gaps with regard to 7Be application as an erosion tracer. Of key importance is the potential for fallout uniformity and rapid tracer sorption to be compromised under certain conditions. The assumption of irreversible sorption is likely to hold for common hillslope conditions but literature identifies the potential for tracer mobility with changing environmental parameters in the wider catchment. Further research is required to determine the likelihood of 7Be sorption being affected by conditions found at relevant field sites and the impact of this upon tracer applications at the catchment-scale.

  6. Microcosm enrichment of biphenyl-degrading microbial communities from soils and sediments

    SciTech Connect

    Wagner-Doebler, I.; Bennasar, A.; Stroempl, C.; Bruemmer, I.; Eichner, C.; Grammel, I.; Moore, E.R.B.; Vancanneyt, M.

    1998-08-01

    A microcosm enrichment approach was employed to isolate bacteria which are representative of long-term biphenyl-adapted microbial communities. Growth of microorganisms was stimulated by incubating soil and sediment samples from polluted and nonpolluted sites with biphenyl crystals. After 6 months, stable population densities between 8 {times} 10{sup 9} and 2 {times} 10{sup 11} CFU/ml were established in the microcosms, and a large percentage of the organisms were able to grow on biphenyl-containing minimal medium plates. A total of 177 biphenyl-degrading strains were subsequently isolated and characterized by their ability to grow on biphenyl in liquid culture and to accumulate a yellow meta cleavage product when they were sprayed with dihydroxy-biphenyl. Isolates were identified by using a polyphasic approach, including fatty acid methyl ester (FAME) analysis, 16S rRNA gene sequence comparison, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins, and genomic fingerprinting based on sequence variability in the 16S-23S ribosomal DNA intergenic spacer region. In all of the microcosms, isolates identified as Rhodococcus opacus dominated the cultivable microbial community, comprising a cluster of 137 isolates with very similar FAME profiles (Euclidean distances, <10) and identical 16S rRNA gene sequences.

  7. A simple method for the quantitative microextraction of polychlorinated biphenyls from soils and sediments.

    SciTech Connect

    Szostek, B.; Tinklenberg, J. A.; Aldstadt, J. H., III; Environmental Research

    1999-01-01

    We demonstrate the quantitative extraction of polychlorinated biphenyls (PCBs) from environmental solids by using a microscale adaptation of pressurized fluid extraction ({mu}PFE). The stainless steel extraction cells are filled with a solid sample and solvent and are heated at elevated temperature. After cooling the cell to room temperature, we determined PCBs in the extract by direct injection to a gas chromatograph with an electron capture detection system. This extraction method was tested on a set of PCB-spiked solid matrices and on a PCB-contaminated river sediment (KIST SRM 1939). Recoveries were measured for eight PCB congeners spiked into two soil types with hexane extraction at 100{sup o}C (>81.9 {+-} 5.4% to 112.5 {+-} 10.1 %). The extraction process for SRM 1939 with hexane at 300{sup o}C provided significantly higher recoveries for several representative PCB congeners than reported for a duplicate 16-hour Soy-Wet extraction with a mixture of organic solvents (acetone/hexane).

  8. Isolation and Characterization of Diverse Halobenzoate-Degrading Denitrifying Bacteria from Soils and Sediments

    PubMed Central

    Song, Bongkeun; Palleroni, Norberto J.; Häggblom, Max M.

    2000-01-01

    Denitrifying bacteria capable of degrading halobenzoates were isolated from various geographical and ecological sites. The strains were isolated after initial enrichment on one of the monofluoro-, monochloro-, or monobromo-benzoate isomers with nitrate as an electron acceptor, yielding a total of 33 strains isolated from the different halobenzoate-utilizing enrichment cultures. Each isolate could grow on the selected halobenzoate with nitrate as the terminal electron acceptor. The isolates obtained on 2-fluorobenzoate could use 2-fluorobenzoate under both aerobic and denitrifying conditions, but did not degrade other halobenzoates. In contrast, the 4-fluorobenzoate isolates degraded 4-fluorobenzoate under denitrifying conditions only, but utilized 2-fluorobenzoate under both aerobic and denitrifying conditions. The strains isolated on either 3-chlorobenzoate or 3-bromobenzoate could use 3-chlorobenzoate, 3-bromobenzoate, and 2- and 4-fluorobenzoates under denitrifying conditions. The isolates were identified and classified on the basis of 16S rRNA gene sequence analysis and their cellular fatty acid profiles. They were placed in nine genera belonging to either the α-, β-, or γ-branch of the Proteobacteria, namely, Acidovorax, Azoarcus, Bradyrhizobium, Ochrobactrum, Paracoccus, Pseudomonas, Mesorhizobium, Ensifer, and Thauera. These results indicate that the ability to utilize different halobenzoates under denitrifying conditions is ubiquitously distributed in the Proteobacteria and that these bacteria are widely distributed in soils and sediments. PMID:10919805

  9. Evaluation of Environmental Risk of Metal Contaminated Soils and Sediments Near Mining Sites in Aguascalientes, Mexico.

    PubMed

    Mitchell, Kerry Nigel; Ramos Gómez, Magdalena Samanta; Guerrero Barrera, Alma Lilian; Yamamoto Flores, Laura; Flores de la Torre, Juan Armando; Avelar González, Francisco Javier

    2016-08-01

    A total of sixteen composite soil and sediment samples were collected during the rainy and dry season in Asientos, Aguascalientes, Mexico, an area recently affected by increased mining operations. Physicochemical characterization showed that substrates were moderately to strongly calcareous with predominantly neutral to slightly alkaline pH, moderate to high cation-exchange capacity and high organic matter content. Due to these conditions, Cd, Pb, Cu and Zn were not water leachable despite high concentrations; up to 105.3, 7052.8, 414.7 and 12,263.2 mg kg(-1) respectively. However, Cd and Pb were considered to be easily mobilizable as they were found predominantly associated with exchangeable and carbonate fractions, whereas Cu and Zn were found associated with Fe/Mn oxide and organic matter fractions. The results highlighted the influence of physicochemical substrate properties on the mobility of metals and its importance during the evaluation of the potential current and future risk metal contamination presents in affected areas.

  10. Evaluation of Environmental Risk of Metal Contaminated Soils and Sediments Near Mining Sites in Aguascalientes, Mexico.

    PubMed

    Mitchell, Kerry Nigel; Ramos Gómez, Magdalena Samanta; Guerrero Barrera, Alma Lilian; Yamamoto Flores, Laura; Flores de la Torre, Juan Armando; Avelar González, Francisco Javier

    2016-08-01

    A total of sixteen composite soil and sediment samples were collected during the rainy and dry season in Asientos, Aguascalientes, Mexico, an area recently affected by increased mining operations. Physicochemical characterization showed that substrates were moderately to strongly calcareous with predominantly neutral to slightly alkaline pH, moderate to high cation-exchange capacity and high organic matter content. Due to these conditions, Cd, Pb, Cu and Zn were not water leachable despite high concentrations; up to 105.3, 7052.8, 414.7 and 12,263.2 mg kg(-1) respectively. However, Cd and Pb were considered to be easily mobilizable as they were found predominantly associated with exchangeable and carbonate fractions, whereas Cu and Zn were found associated with Fe/Mn oxide and organic matter fractions. The results highlighted the influence of physicochemical substrate properties on the mobility of metals and its importance during the evaluation of the potential current and future risk metal contamination presents in affected areas. PMID:27178544

  11. Impact of WWII dumpsites on Saipan (CNMI): heavy metal status of soils and sediments.

    PubMed

    Denton, Gary R W; Emborski, Carmen A; Hachero, April A B; Masga, Ray S; Starmer, John A

    2016-06-01

    A number of dumpsites occur on the island of Saipan and in the surrounding coastal waters. Many of these sites date back to the immediate post WWII clean-up period and contain a variety of wartime wastes. Metallic debris is generally the most visible waste material and commonly includes bomb fragments, artillery shells, bullets, and other military hardware. In this investigation, we examined the heavy metal status of soils from around several of these dumpsites and in any obvious drainage pathways leading from them to the coast. Sediments were also taken for analysis from a number of coastal discharge points and three submerged sites. Metal enrichment was evident for one or more elements in deposits from two of the three submerged sites and 24 of the 32 land-based sites visited. Copper, Pb, and Zn were the most commonly encountered contaminant metals with levels well in excess of 1000 μg/g(-1) in several instances. Elevated Hg and Cd concentrations were also relatively widespread throughout the study area although levels of each element seldom exceeded 1.0 and 10.0 μg/g(-1), respectively. Silver, another element of toxicological concern, was only occasionally detected despite registering a high of 42 μg/g(-1) at one particular site. The metal data were weighed against established benchmarks formulated for the protection of human and ecological health. Implications of the findings and issues of primary concern are briefly addressed.

  12. Trace element reactivity in FeS-rich estuarine sediments: influence of formation environment and acid sulfate soil drainage.

    PubMed

    Morgan, Bree; Rate, Andrew W; Burton, Edward D

    2012-11-01

    Iron monosulfides (FeS) precipitate during benthic mineralisation of organic C and are well known to have a strong influence on trace element bioavailability in sediments. In this study we investigate the reactivity of trace elements (As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Zn) in sediments containing abundant and persistent FeS stores, collected from a south-western Australian estuarine system. Our objective was to explore the influence of sediment formation conditions on trace element reactivity by investigating sediments collected from different environments, including estuarine, riverine and acid sulfate soil influenced sites, within a single estuarine system. In general, we found a higher degree of reactivity (defined by 1 mol/L HCl extractions) for Cd, Mn, Pb and Zn, compared with a lower reactivity of As, Co, Cr, Cu, Mo and Ni. Moderate to strong correlations (R(2)>0.4, P<0.05) were observed between AVS and reactive Cd, Co, Mn, Mo, Ni, Pb and Zn within many of the formation environments. In contrast, correlations between AVS and As, Cr and Cu were generally poor (not significant, R(2)<0.4, P>0.05). Based on their reactivity and correlations with AVS, it appears that interactions (sorption, co-precipitation) between FeS and Cd, Mn, Pb and Zn in many of the sediments from this study are probable. Our data also demonstrate that drainage from acid sulfate soils (ASS) can be a source of trace elements at specific sites. A principal components analysis of our reactive (1 mol/L HCl extractable) trace element data clearly distinguished sites receiving ASS drainage from the other non-impacted sites, by a high contribution from Fe-Co-Mn-Ni along the first principal axis, and contributions from higher S-As/lower reactive Pb along the second axis. This demonstrates that trace element reactivity in sediments may provide a geochemical signature for sites receiving ASS drainage.

  13. Sources and characteristics of organochlorine pesticides in the soil and sediment along the Kaidu-Peacock River, Northwest of China

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Qi, Shihua; Peng, Fei; Qu, Chengkai; Zhang, Yuan; Xing, Xinli; Zhang, Jiaquan

    2016-04-01

    Organochlorine pesticides (OCPs) are a sub-group of persistent organic pollutants (POPs), which have raised the concerns from researchers all around the world for several decades. But very little research has been conducted on POPs in the arid zone of Northwest China. More than 100 soil and sediment samples were collected from Kaidu-Peacock River of Xinjiang, Northwest of China, to investigate the organochlorine pesticides (OCPs) in this region analysed by the gas chromatograph equipped with a mass selective detector (GC-MSD). Our pre-study in 2006 (Chen et al. 2011) in the same region, showed that OCPs except o,p'-DDT were detected in sediments from the Peacock River. Similar results were found in the whole river catchment in this investigation. DDTs, HCHs, chlordanes and endosulfans were the dominant OCPs residual in the soil and sediments. This study confirmed that POPs, such as OCPs in this region were contributed to by both local emissions and long-term atmospheric transport and may pose risks to human health and the ecosystem. Chen, W., Jing, M., Bu, J., Ellis Burnet, J., Qi, S., Song, Q., Ke, Y., Miao, J., Liu, M. & Yang, C. (2011) Organochlorine pesticides in the surface water and sediments from the Peacock River Drainage Basin in Xinjiang, China: a study of an arid zone in Central Asia. Environmental Monitoring and Assessment, 177, 1-21.

  14. Improvement of the BCR three step sequential extraction procedure prior to the certification of new sediment and soil reference materials.

    PubMed

    Rauret, G; López-Sánchez, J F; Sahuquillo, A; Rubio, R; Davidson, C; Ure, A; Quevauviller, P

    1999-02-01

    The Standards, Measurements and Testing Programme (formerly BCR) of the European Commission proposed a three-step sequential extraction procedure for sediment analysis, following extensive expert consultations and two interlaboratory studies. This scheme was recently used to certify the extractable trace element contents of a sediment reference material (CRM 601). Although this procedure offers a means to ensure the comparability of data in this field, some difficulties concerning the interlaboratory reproducibility still remain, and a new project is currently being conducted to determine the causes of poor reproducibility in the extraction scheme. The final objective of the project is the certification of new sediment and soil reference materials for their extractable contents of Cd, Cr, Cu, Ni, Pb and Zn. This paper presents the results of a small-scale interlaboratory study, which aimed to test a revised version of the extraction schemes by comparing the original and the modified protocols using the CRM 601 sample. This work offers an improvement to the BCR sequential extraction procedure through intercomparison exercises. This improved procedure will allow the obtaining of CRMs to validate analytical data in the analysis of soils and sediments, and it will also facilitate comparability of data in the European Union.

  15. Chemical quality of depositional sediments and associated soils in New Orleans and the Louisiana peninsula following Hurricane Katrina

    USGS Publications Warehouse

    Adams, C.; Witt, E.C.; Wang, Jingyuan; Shaver, D.K.; Summers, D.; Filali-Meknassi, Y.; Shi, H.; Luna, R.; Anderson, N.

    2007-01-01

    Hurricane Katrina made landfall on the Louisiana peninsula south of New Orleans on Aug 29, 2005. The resulting storm surge caused numerous levy breaches in the parishes of New Orleans as well as on the Louisiana peninsula. This study was conducted to determine the concentrations of inorganic and organic constituents in sediments and associated soils in New Orleans parishes and the Louisiana peninsula after the floodwaters had been removed and/or receded following Hurricane Katrina. A total of 46 sediment and soil samples were analyzed that were collected throughout New Orleans and the Louisiana peninsula. Approximately 20% of the sediment samples were analyzed, including shallow sediment samples from locations that included the top and beneath automobiles, in residential and commercial areas, and near refineries. Gasoline constituents, pesticides, and leachable heavy metals were analyzed using headspace gas chromatography/mass spectrometry (GC/MS), organic extraction GC/MS, and inductively coupled plasma/mass spectrometry, respectively. A significant number of samples had leachable As and Pb concentrations in excess of drinking water standards. The remaining metals analyzed (i.e., Cd, Cr, Cu, Hg, and V) generally had much lower leachable levels. Of the gasoline constituents, only benzene was observed above the limit of detection (of 5 ??g/kg), with no samples observed as being above the method detection limits of 10 ??g/kg. For the 18 pesticides analyzed, most were in the nondetectable range and all were in trace amounts that were orders of magnitude below regulatory guidelines. ?? 2007 American Chemical Society.

  16. Chemical quality of depositional sediments and associated soils in New Orleans and the Louisiana peninsula following Hurricane Katrina.

    PubMed

    Adams, Craig; Witt, Emitt C; Wang, Jianmin; Shaver, David K; Summers, David; Filali-Meknassi, Youssef; Shi, Honglan; Luna, Ronaldo; Anderson, Neil

    2007-05-15

    Hurricane Katrina made landfall on the Louisiana peninsula south of New Orleans on Aug 29, 2005. The resulting storm surge caused numerous levy breaches in the parishes of New Orleans as well as on the Louisiana peninsula. This study was conducted to determine the concentrations of inorganic and organic constituents in sediments and associated soils in New Orleans parishes and the Louisiana peninsula after the floodwaters had been removed and/or receded following Hurricane Katrina. A total of 46 sediment and soil samples were analyzed that were collected throughout New Orleans and the Louisiana peninsula. Approximately 20% of the sediment samples were analyzed, including shallow sediment samples from locations that included the top and beneath automobiles, in residential and commercial areas, and near refineries. Gasoline constituents, pesticides, and leachable heavy metals were analyzed using headspace gas chromatography/mass spectrometry (GC/MS), organic extraction GC/MS, and inductively coupled plasma/mass spectrometry, respectively. A significant number of samples had leachable As and Pb concentrations in excess of drinking water standards. The remaining metals analyzed (i.e., Cd, Cr, Cu, Hg, and V) generally had much lower leachable levels. Of the gasoline constituents, only benzene was observed above the limit of detection (of 5 microg/kg), with no samples observed as being above the method detection limits of 10 microg/kg. For the 18 pesticides analyzed, most were in the nondetectable range and all were in trace amounts that were orders of magnitude below regulatory guidelines.

  17. [Fractions and adsorption characteristics of phosphorus on sediments and soils in water level fluctuating zone of the Pengxi River, a tributary of the Three Gorges Reservoir].

    PubMed

    Sun, Wen-Bin; Du, Bin; Zhao, Xiu-Lan; He, Bing-Hui

    2013-03-01

    The sediment, one of the key factors leading to the eutrophication of water bodies, is an important ecological component of natural water body. In order to investigate the morphological characteristics and moving-transiting rule of phosphorus in the sediments of the Pengxi River, a tributary of the Three Gorges Reservoir, the distributions of different phosphorus forms on the three cross-section in the sediments and three soil types of riparian zone were investigated using the sequential extraction method. The characteristics of phosphorus adsorption on the sediments were also investigated by batch experiments. The equilibrium phosphorus concentrations at zero adsorption (EPC0) on those sediments were estimated using the Henry linear models. The results show that the total phosphorus (TP) contents of these sediments and soils of riparian zone were 0.80-1.45 g x kg(-1) and 0.65-1.16 g x kg(-1), respectively. Phosphorus in sediments and soils were divided into inorganic phosphorus (IP) and organic phosphorus (Or-P), and the inorganic phosphorus was the dominant component of TP. Of the inorganic phosphorus fractions, the percentages of phosphorus bounded to calcium (Ca-P) and occluded phosphorus (O-P) from sediments were higher than 80%, implying that the contents of phosphorus were mainly influenced by their bedrocks and the sedimentary environmental conditions, not by the activities of human beings. The fractions of Ca-P and O-P were the dominant components of inorganic phosphorus in alluvial soil and purple soil, while the fraction of O-P was the highest in the paddy soil. The EPC0 values of the sediments from the sections of Huangshi, Shuangjiang and Gaoyang were 0.08, 0.13 and 0.11 mg x L(-1) respectively, but the EPC0 values of the alluvial soil, purple soil and paddy soil located in riparian zone were 0.08, 0.09 and 0.04 mg x L(-1), respectively. Correlation analysis shows that the values of EPC0 positively related to the contents of total phosphorus and clay

  18. Precipitation-runoff, suspended-sediment, and flood-frequency characteristics for urbanized areas of Elmendorf Air Force Base, Alaska

    USGS Publications Warehouse

    Brabets, Timothy P.

    1999-01-01

    The developed part of Elmendorf Air Force Base near Anchorage, Alaska, consists of two basins with drainage areas of 4.0 and 0.64 square miles, respectively. Runoff and suspended-sediment data were collected from August 1996 to March 1998 to gain a basic understanding of the surface-water hydrology of these areas and to estimate flood-frequency characteristics. Runoff from the larger basin averaged 6 percent of rainfall, whereas runoff from the smaller basin averaged 13 percent of rainfall. During rainfall periods, the suspended-sediment load transported from the larger watershed ranged from 179 to 21,000 pounds and that from the smaller watershed ranged from 23 to 18,200 pounds. On a yield basis, suspended sediment from the larger watershed was 78 pounds per inch of runoff and from the smaller basin was 100 pounds per inch of runoff. Suspended-sediment loads and yields were generally lower during snowmelt periods than during rainfall periods. At each outfall of the two watersheds, water flows into steep natural channels. Suspended-sediment loads measured approximately 1,000 feet downstream from the outfalls during rainfall periods ranged from 8,450 to 530,000 pounds. On a yield basis, suspended sediment averaged 705 pounds per inch of runoff, more than three times as much as the combined sediment yield from the two watersheds. The increase in suspended sediment is most likely due to natural erosion of the streambanks. Streamflow data, collected in 1996 and 1997, were used to calibrate and verify a U.S. Geological Survey computer model?the Distributed Routing Rainfall Runoff Model-Version II (DR3M-II). The model was then used to simulate annual peak discharges and runoff volumes for 1981 to 1995 using historical rainfall records. Because the model indicated that surcharging (or ponding) would occur, no flood-frequency analysis was done for peak discharges. A flood-frequency analysis of flood volumes indicated that a 10-year flood would result in 0.39 inch of runoff

  19. Speciation and Fate of Trace Metals in Estuarine Sediments Under Reduced and Oxidized Conditions, Seaplane Lagoon, Alameda Naval Air Station

    SciTech Connect

    Carroll, S A; Day, P A; Esser, B; Randall, S

    2002-10-18

    We have identified important chemical reactions that control the fate of metal-contaminated estuarine sediments if they are left undisturbed (in situ) or if they are dredged. We combined information on the molecular bonding of metals in solids from X-ray absorption spectroscopy (XAS) with thermodynamic and kinetic driving forces obtained from dissolved metal concentrations to deduce the dominant reactions under reduced and oxidized conditions. We evaluated the in situ geochemistry of metals (cadmium, chromium, iron, lead, manganese and zinc) as a function of sediment depth (to 100 cm) from a 60-year record of contamination at the Alameda Naval Air Station, California. Results from XAS and thermodynamic modeling of porewaters show that cadmium and most of the zinc form stable sulfide phases, and that lead and chromium are associated with stable carbonate, phosphate, phyllosilicate, or oxide minerals. Therefore, there is minimal risk associated with the release of these trace metals from the deeper sediments contaminated prior to the Clean Water Act (1975)