Science.gov

Sample records for metal contaminants quarterly

  1. Phytoremediation of Metal-Contaminated Soils

    SciTech Connect

    Shtangeeva, I.; Laiho, J.V-P.; Kahelin, H.; Gobran, G.R.

    2004-03-31

    Recent concerns regarding environmental contamination have necessitated the development of appropriate technologies to assess the presence and mobility of metals in soil and estimate possible ways to decrease the level of soil metal contamination. Phytoremediation is an emerging technology that may be used to cleanup contaminated soils. Successful application of phytoremediation, however, depends upon various factors that must be carefully investigated and properly considered for specific site conditions. To efficiently affect the metal removal from contaminated soils we used the ability of plants to accumulate different metals and agricultural practices to improve soil quality and enhance plant biomass. Pot experiments were conducted to study metal transport through bulk soil to the rhizosphere and stimulate transfer of the metals to be more available for plants' form. The aim of the experimental study was also to find fertilizers that could enhance uptake of metals and their removal from contaminated soil.

  2. Detecting contamination on a metal surface

    NASA Technical Reports Server (NTRS)

    Harris, J. M.; Marcus, H. L.; Smith, T.

    1977-01-01

    Thin layers of contaminant on metal surface are detected by measuring surface-potential difference between reference electrode and surface of interest. Procedure does not require mechanical contact with surface under examination.

  3. Catalyst regeneration process including metal contaminants removal

    DOEpatents

    Ganguli, Partha S.

    1984-01-01

    Spent catalysts removed from a catalytic hydrogenation process for hydrocarbon feedstocks, and containing undesired metals contaminants deposits, are regenerated. Following solvent washing to remove process oils, the catalyst is treated either with chemicals which form sulfate or oxysulfate compounds with the metals contaminants, or with acids which remove the metal contaminants, such as 5-50 W % sulfuric acid in aqueous solution and 0-10 W % ammonium ion solutions to substantially remove the metals deposits. The acid treating occurs within the temperature range of 60.degree.-250.degree. F. for 5-120 minutes at substantially atmospheric pressure. Carbon deposits are removed from the treated catalyst by carbon burnoff at 800.degree.-900.degree. F. temperature, using 1-6 V % oxygen in an inert gas mixture, after which the regenerated catalyst can be effectively reused in the catalytic process.

  4. CONTAMINANTS AND REMEDIAL OPTIONS AT SELECTED METAL-CONTAMINATED SITES

    EPA Science Inventory

    This document provides information that facilitates characterization of the site and selection of treatment technologies at metals-contaminated sites that would be capable of meeting site-specific cleanup levels. he document does not facilitate the determination of cleanup levels...

  5. Catalytic extraction processing of contaminated scrap metal

    SciTech Connect

    Griffin, T.P.; Johnston, J.E.

    1994-12-31

    The contract was conceived to establish the commercial capability of Catalytic Extraction Processing (CEP) to treat contaminated scrap metal in the DOE inventory. In so doing, Molten Metal Technology, Inc. (MMT), pursued the following objectives: demonstration of the recycling of ferrous and non-ferrous metals--to establish that radioactively contaminated scrap metal can be converted to high-grade, ferrous and non-ferrous alloys which can be reused by DOE or reintroduced into commerce; immobilize radionuclides--that CEP will concentrate the radionuclides in a dense vitreous phase, minimize secondary waste generation and stabilize and reduce waste volume; destroy hazardous organics--that CEP will convert hazardous organics to valuable industrial gases, which can be used as feed gases for chemical synthesis or as an energy source; recovery volatile heavy metals--that CEP`s off-gas treatment system will capture volatile heavy metals, such as mercury and lead; and establish that CEP is economical for processing contaminated scrap metal in the DOE inventory--that CEP is a more cost-effective and, complete treatment and recycling technology than competing technologies for processing contaminated scrap. The process and its performance are described.

  6. Aromatic plant production on metal contaminated soils.

    PubMed

    Zheljazkov, Valtcho D; Craker, Lyle E; Xing, Baoshan; Nielsen, Niels E; Wilcox, Andrew

    2008-06-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha(-1) for Cd, 660 g ha(-1) for Pb, 180 g ha(-1) for Cu, 350 g ha(-1) for Mn, and 205 g ha(-1) for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (<1 microm) particles, although there were larger particles (1-5 microm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil. PMID:18353428

  7. Heavy metal contamination from geothermal sources.

    PubMed

    Sabadell, J E; Axtmann, R C

    1975-12-01

    Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavy metals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavy metal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavy metal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavy metals. PMID:1227849

  8. Heavy metal contamination from geothermal sources.

    PubMed Central

    Sabadell, J E; Axtmann, R C

    1975-01-01

    Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavy metals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavy metal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavy metal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavy metals. PMID:1227849

  9. Hazards of heavy metal contamination.

    PubMed

    Järup, Lars

    2003-01-01

    The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years. Although several adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues, and is even increasing in some parts of the world, in particular in less developed countries, though emissions have declined in most developed countries over the last 100 years. Cadmium compounds are currently mainly used in re-chargeable nickel-cadmium batteries. Cadmium emissions have increased dramatically during the 20th century, one reason being that cadmium-containing products are rarely re-cycled, but often dumped together with household waste. Cigarette smoking is a major source of cadmium exposure. In non-smokers, food is the most important source of cadmium exposure. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage but possibly also bone effects and fractures. Many individuals in Europe already exceed these exposure levels and the margin is very narrow for large groups. Therefore, measures should be taken to reduce cadmium exposure in the general population in order to minimize the risk of adverse health effects. The general population is primarily exposed to mercury via food, fish being a major source of methyl mercury exposure, and dental amalgam. The general population does not face a significant health risk from methyl mercury, although certain groups with high fish consumption may attain blood levels associated with a low risk of neurological damage to adults. Since there is a risk to the fetus in particular, pregnant women should avoid a high intake of certain fish, such as shark, swordfish and

  10. The remediation of heavy metals contaminated sediment.

    PubMed

    Peng, Jian-Feng; Song, Yong-Hui; Yuan, Peng; Cui, Xiao-Yu; Qiu, Guang-Lei

    2009-01-30

    Heavy metal contamination has become a worldwide problem through disturbing the normal functions of rivers and lakes. Sediment, as the largest storage and resources of heavy metal, plays a rather important role in metal transformations. This paper provides a review on the geochemical forms, affecting factors and remediation technologies of heavy metal in sediment. The in situ remediation of sediment aims at increasing the stabilization of some metals such as the mobile and the exchangeable fractions; whereas, the ex situ remediation mainly aims at removing those potentially mobile metals, such as the Mn-oxides and the organic matter (OM) fraction. The pH and OM can directly change metals distribution in sediment; however oxidation-reduction potential (ORP), mainly through changing the pH values, indirectly alters metals distribution. Mainly ascribed to their simple operation mode, low costs and fast remediation effects, in situ remediation technologies, especially being fit for slight pollution sediment, are applied widely. However, for avoiding metal secondary pollution from sediment release, ex situ remediation should be the hot point in future research. PMID:18547718

  11. BIOAVAILABILITY OF METALS IN CONTAMINATED SOIL AND DUST

    EPA Science Inventory

    Due to widespread metal contamination, it is necessary to characterize soils suspected of metal contamination and determine if the metal levels in these soils pose a hazard. Metal toxicity is often not directly related to the total concentration of metals present due to a numb...

  12. Detecting hydrogen-containing contaminants on metal surfaces

    NASA Technical Reports Server (NTRS)

    Grove, E. L.; Losele, W. A.

    1969-01-01

    Spark emission spectroscopy analyzes surface contamination of metals. This technique controls the quality of surface preparations and is useful in fundamental investigations of surface properties of metals.

  13. Heavy metal contaminants in yerberia shop products.

    PubMed

    Levine, Michael; Mihalic, Jason; Ruha, Anne-Michelle; French, Robert N E; Brooks, Daniel E

    2013-03-01

    Complementary and alternative medications, including the use of herbal medications, have become quite popular in the USA. Yerberias are found throughout the southwest and specialize in selling Hispanic herbal products. The products sold in these stores are not regulated by any governmental agency. Previous reports have found Ayurvedic medications contain high levels of lead, mercury, and arsenic. The primary purpose of this study is to examine the prevalence of heavy metal contaminants sold at Yerberia stores in the southwest. Yerberias in the Phoenix, Arizona area were identified via search of an on-line search engine using the words "Yerberia Phoenix." Every second store was selected, and products were purchased using a standard script. The products were subsequently analyzed for mercury, lead, and arsenic. The main outcome is the prevalence of heavy metal content in over-the-counter "cold" medications purchased at a Yerberia. Twenty-two samples were purchased. One product contained pure camphor (2-camphone) and was subsequently not further analyzed. Of the 21 samples analyzed, lead was found in 4/21 (19.4 %). Arsenic and mercury were in 1/21 (4.8 %) each. Because two samples contained two heavy metals, the total prevalence of heavy metals was 4/21 (19.4). Heavy metal contaminants are commonly encountered in over-the-counter herbal "cold" medications purchased at Yerberias in the southwest. PMID:22562238

  14. Earthworm contamination by PCBs and heavy metals

    SciTech Connect

    Diercxsens, P.; de Weck, D.; Borsinger, N.; Rosset, B.; Tarradellas, J.

    1985-01-01

    A comparison is made of soil and earthworm contamination by PCBs and heavy metals between a nature reserve and two sites conditioned by the addition of sewage sludge and compost. The tissues and gut content of the earthworms shows a higher PCB concentration than that of the surrounding soil and also a difference in the fingerprint of some single PCB compounds. Earthworms display a selective accumulation of cadmium and zinc in their tissues and gut content.

  15. RESULTS FOR THE FOURTH QUARTER 2011 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Bannochie, C.

    2012-01-31

    The Saltstone Facility is designed and permitted to immobilize and dispose of low-level radioactive and hazardous liquid waste (salt solution) remaining from the processing of radioactive material at the Savannah River Site. Low-level waste (LLW) streams from the Effluent Treatment Project (ETP), H-Canyon, and the decontaminated salt solution product from the Actinide Removal Process/Modular Caustic Side Solvent Extraction (CSSX) Unit (ARP/MCU) process are stored in Tank 50 until the LLW can be transferred to the Saltstone Facility for treatment and disposal. The LLW must meet the specified waste acceptance criteria (WAC) before it is processed into saltstone. The specific chemical and radionuclide contaminants and their respective WAC limits are in the current Saltstone WAC. Waste Solidification Engineering (WSE) requested that Savannah River National Laboratory (SRNL) perform quarterly analysis on saltstone samples. The concentrations of chemical and radionuclide contaminants are measured to ensure the saltstone produced during each quarter is in compliance with the current WAC. This report documents the concentrations of chemical and radionuclide contaminants for the 2011 Fourth Quarter samples collected from Tank 50 on October 12, 2011 and discusses those results in further detail than the previously issued results report.

  16. RESULTS FOR THE THIRD QUARTER 2011 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.

    2011-10-20

    The Saltstone Facility is designed and permitted to immobilize and dispose of low-level radioactive and hazardous liquid waste (salt solution) remaining from the processing of radioactive material at the Savannah River Site. Low-level waste (LLW) streams from the Effluent Treatment Project (ETP), H-Canyon, and the decontaminated salt solution product from the Actinide Removal Process/Modular Caustic Side Solvent Extraction (CSSX) Unit (ARP/MCU) process are stored in Tank 50 until the LLW can be transferred to the Saltstone Facility for treatment and disposal. The LLW must meet the specified waste acceptance criteria (WAC) before it is processed into saltstone. The specific chemical and radionuclide contaminants and their respective WAC limits are in the current Saltstone WAC. Waste Solidification Engineering (WSE) requested that Savannah River National Laboratory (SRNL) perform quarterly analysis on saltstone samples. The concentrations of chemical and radionuclide contaminants are measured to ensure the saltstone produced during each quarter is in compliance with the current WAC. This report documents the concentrations of chemical and radionuclide contaminants for the 2011 Third Quarter samples collected from Tank 50 on July 7, 2011 and discusses those results in further detail than the previously issued results report.

  17. Catalytic extraction processing of contaminated scrap metal

    SciTech Connect

    Griffin, T.P.; Johnston, J.E.; Payea, B.M.

    1995-10-01

    The U.S. Department of Energy issued a Planned Research and Development Announcement (PRDA) in 1993, with the objective of identifying unique technologies which could be applied to the most hazardous waste streams at DOE sites. The combination of radioactive contamination with additional contamination by hazardous constituents such as those identified by the Resource Conservation and Recovery Act (RCRA) pose an especially challenging problem. Traditional remediation technologies are increasingly becoming less acceptable to stakeholders and regulators because of the risks they pose to public health and safety. Desirable recycling technologies were described by the DOE as: (1) easily installed, operated, and maintained; (2) exhibiting superior environmental performance; (3) protective of worker and public health and safety; (4) readily acceptable to a wide spectrum of evaluators; and (5) economically feasible. Molten Metal Technology, Inc. (MMT) was awarded a contract as a result of the PRDA initiative to demonstrate the applicability of Catalytic Extraction Processing (CEP), MMT`s proprietary elemental recycling technology, to DOE`s inventory of low level mixed waste. This includes DOE`s inventory of radioactively- and RCRA-contaminated scrap metal and other waste forms expected to be generated by the decontamination and decommissioning (D&D) of DOE sites.

  18. Results for the second quarter 2014 tank 50 WAC slurry sample chemical and radionuclide contaminants

    SciTech Connect

    Bannochie, C.

    2014-09-04

    This report details the chemical and radionuclide contaminant results for the characterization of the 2014 Second Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC) in effect at that time. Information from this characterization will be used by DWPF & Saltstone Facility Engineering (DSFE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System.

  19. Results For The Fourth Quarter 2014 Tank 50 WAC Slurry Sample: Chemical And Radionuclide Contaminants

    SciTech Connect

    Crawford, C.

    2015-09-30

    This report details the chemical and radionuclide contaminant results for the characterization of the Calendar Year (CY) 2014 Fourth Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC) in effect at that time. Information from this characterization will be used by DWPF & Saltstone Facility Engineering (DSFE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System.

  20. Results For The Second Quarter 2013 Tank 50 WAC Slurry Sample: Chemical And Radionuclide Contaminants

    SciTech Connect

    Bannochie, Christopher J.

    2013-07-31

    This report details the chemical and radionuclide contaminant results for the characterization of the 2013 Second Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC) in effect at that time. Information from this characterization will be used by Saltstone Facility Engineering (SFE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System.

  1. Results for the Third Quarter 2012 Tank 50 WAC Slurry Sample: Chemical and Radionuclide Contaminants

    SciTech Connect

    Bannochie, C. J.

    2012-10-26

    This report details the chemical and radionuclide contaminant results for the characterization of the 2012 Third Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Waste Solidification Engineering (WSE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System.

  2. RESULTS FOR THE SECOND QUARTER 2011 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Eibling, R.

    2011-08-25

    The Saltstone Facility is designed and permitted to immobilize and dispose of low-level radioactive and hazardous liquid waste (salt solution) remaining from the processing of radioactive material at the Savannah River Site. Low-level waste (LLW) streams from the Effluent Treatment Project (ETP), H-Canyon, the DDA (Deliquification, Dissolution, and Adjustment) process, and the decontaminated salt solution product from the Actinide Removal Process/Modular Caustic Side Solvent Extraction (CSSX) Unit (ARP/MCU) process are stored in Tank 50 until the LLW can be transferred to the Saltstone Facility for treatment and disposal. The LLW must meet the specified waste acceptance criteria (WAC) before it is processed into saltstone. The specific chemical and radionuclide contaminants and their respective WAC limits are listed in the current Saltstone WAC. Waste Solidification Engineering (WSE) requested that Savannah River National Laboratory (SRNL) perform quarterly analysis on saltstone samples. The concentrations of chemical and radionuclide contaminants are measured to ensure the saltstone produced during each quarter is in compliance with the current WAC. This report documents the concentrations of chemical and radionuclide contaminants for the 2011 Second Quarter samples collected from Tank 50 on April 4, 2011 and discusses those results in further detail than the previously issued results report. The following conclusions are drawn from the analytical results provided in this report: (1) The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted in this section. (2) The reported detection limit for {sup 59}Ni is above the requested limit from Reference 2 but below the established limit in Reference 3. (3) The reported detection limit for {sup 94}Nb is above the requested limit from Reference 2; however, it is below the established limits in Reference 3. (4) The reported concentration of

  3. RESULTS FOR THE FOURTH QUARTER TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.; Bibler, N.

    2010-01-27

    The Saltstone Facility is designed and permitted to immobilize and dispose of low-level radioactive and hazardous liquid waste (salt solution) remaining from the processing of radioactive material at the Savannah River Site. Low-level waste (LLW) streams from the Effluent Treatment Project (ETP), H-Canyon, the DDA (Deliquification, Dissolution, and Adjustment) process, and the decontaminated salt solution product from the Actinide Removal Process/Modular Caustic Side Solvent Extraction (CSSX) Unit (ARP/MCU) process are stored in Tank 50 until the LLW can be transferred to the Saltstone Facility for treatment and disposal. The LLW must meet the specified waste acceptance criteria (WAC) before it is processed into saltstone. The specific chemical and radionuclide contaminants and their respective WAC limits are listed in the current Saltstone WAC. SRS Liquid Waste Operations (LWO) requested that Savannah River National Laboratory (SRNL) perform quarterly analysis on saltstone samples. The concentrations of chemical and radionuclide contaminants are measured to ensure the saltstone produced during each quarter is in compliance with the current WAC. This report documents the concentrations of chemical and radionuclide contaminants for the 2009 Fourth Quarter samples collected from Tank 50 on October 2, 2009 and discusses those results in further detail than the previously issued results report. This report details the chemical and radionuclide contaminant results for the characterization of the 2009 Fourth Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Liquid Waste Operations (LWO) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results

  4. RESULTS FOR THE FOURTH QUARTER 2010 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M

    2011-02-22

    This report details the chemical and radionuclide contaminant results for the characterization of the 2010 Fourth Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Liquid Waste Operations (LWO) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: (1) The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted in this section. (2) The reported detection limits for {sup 94}Nb, {sup 247}Cm and {sup 249}Cf are above the requested limits from Reference 2. However, they are below the limits established in Reference 3. (3) There is an estimated concentration of trimethylbenzene (2.25 mg/L). This is not a WAC analyte, but it is the first time this organic compound has been detected in a quarterly WAC sample from Tank 50. (4) The reported detection limit for Norpar 13 is greater than the limit from Table 4 and Attachment 8.2 of the WAC. (5) The reported detection limit for Isopar L is greater than the limit from Table 3 of the WAC. (6) Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples. The values reported in this memo are the concentrations in the sub-sample as detected by the GC/MS; however, the results may not accurately represent the concentrations of the analytes in Tank 50.

  5. RESULTS FOR THE FOURTH QUARTER 2013 TANK 50 WAC SLURRY SAMPLE CHEMICAL AND RADIONUCLIDE CONTAMINANTS

    SciTech Connect

    Bannochie, C.

    2014-04-01

    This report details the chemical and radionuclide contaminant results for the characterization of the 2013 Fourth Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC) in effect at that time. Information from this characterization will be used by DWPF & Saltstone Facility Engineering (DSFE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report:  SRR WAC targets or limits were met for all analyzed chemical and radioactive contaminants unless noted in this section.  {sup 59}Ni, {sup 94}Nb, {sup 247}Cm, {sup 249}Cf, and {sup 251}Cf are above the requested SRR target concentrations. However, they are below the detection limits established by SRNL.  Norpar 13 and Isopar L have higher detection limits compared with the Saltstone WAC. The data provided in this report is based upon the concentrations in the sub-sample, and due to the limited solubility of these materials in aqueous solution, may not represent the concentrations of the analytes in Tank 50.  The low insoluble solids content increases the measurement uncertainty for insoluble species. The semivolatile organic analysis (SVOA) method employed in the measurement of Norpar 13 and tributyl phosphate (TBP) has resulted in the erroneous reporting of a variety of small chain alcohols, including 4-methyl-3-hexanol and 5-methyl-3-hexanol, in previous quarterly sample reports. It has now been determined that these alcohols are an artifact of the sample preparation. Further work is being conducted in SRNL to delineate the conditions that produce these alcohols, and these findings will be reported separately.

  6. Microbial recovery of metals from spent catalysts. Quarterly report, April--June, 1990

    SciTech Connect

    Sperl, P.L.; Sperl, G.T.

    1990-12-31

    The second quarter of 1990 was one of peripheral progress on the project of reclaiming molybdenum and nickel from spent coal liquefaction catalysts. We defined some important parameters for future research and we were able to clear up ambiguities in some of the past approaches and the problems uniquely associated with the ability of T. ferrooxidans to leach both Ni{sup ++} and molybdate from spent, alumina supported catalyst from the Wilsonville pilot project. We were also able to show the T. ferrooxidans was very sensitive to molybdate and extremely sensitive to tungstate, but showed relatively little sensitivity for the related elements chromate, vanadate and for the catalyst associated metal, Ni{sup ++}. There appears to be no negative synergistic effects between Ni{sup ++} and molybdate for growth, which bodies well for processes to reclaim both these metals from spent coal liquefaction catalysts. We have shown that T. ferrooxidans is indeed capable of leaching molybdate and Ni{sup ++} from spent catalysts if the catalyst is washed extensively with both an organic solvent such as tetrahydrofuran to remove the oily contaminants and an aqueous acidic medium to remove readily solubilized N{sup ++} and molybdate. It is possible to extract into an acidic medium enough molybdate from THF washed spent catalyst within 24 hr to completely inhibit the growth of all tested T. ferrooxidans strains. The stage is now set for the development of a molybdate tolerant strain to be used for actual leaching of the spent catalyst. We are currently seeking simpler ways of pretreating the raw spent catalyst in order to make it more amenable to microbial leaching and possibly produce an economic and feasible technology.

  7. History of metal contamination in Lake Illawarra, NSW, Australia.

    PubMed

    Schneider, Larissa; Maher, William; Potts, Jaimie; Batley, Graeme; Taylor, Anne; Krikowa, Frank; Chariton, Anthony; Zawadzki, Atun; Heijnis, Henk; Gruber, Bernd

    2015-01-01

    Lake Illawarra has a long history of sediment contamination, particularly by metals, as a result of past and current industrial operations and land uses within the catchment. In this study, we examined the history of metal contamination in sediments using metal analysis and (210)Pb and (137)Cs dating. The distributions of copper, zinc, arsenic, selenium, cadmium and lead concentrations within sediment cores were in agreement with historical events in the lake, and indicated that metal contamination had been occurring since the start of industrial activities in Port Kembla in the late 1800 s. Most metal contamination, however, has occurred since the 1960s. Sedimentation rates were found to be 0.2 cm year(-1) in Griffins Bay and 0.3 cm year(-1) in the centre of the lake. Inputs from creeks bringing metals from Port Kembla in the northeast of the lake and a copper slag emplacement from a former copper refinery on the Windang Peninsula were the main sources of metal inputs to Lake Illawarra. The metals of highest concern were zinc and copper, which exceeded the Australian and New Zealand sediment quality guideline values at some sites. Results showed that while historical contamination persists, current management practices have resulted in reduced metal concentrations in surface sediments in the depositional zones in the centre of the lake. PMID:25061943

  8. Results For The First Quarter 2012 Tank 50 WAC Slurry Sample: Chemical And Radionuclide Contaminant Results

    SciTech Connect

    Bannochie, C. J.

    2012-07-16

    This report details the chemical and radionuclide contaminant results for the characterization of the 2012 First Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Waste Solidification Engineering (WSE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this memorandum: The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted; The reported detection limit for {sup 94}Nb is above the requested limit but below the estimated limit; {sup 247}Cm and {sup 249}Cf are above the requested limits. However, they are below the limits established; The reported detection limit for Norpar 13 is greater than the limit from the WAC; The reported detection limit for Isopar L is greater than the limit from WAC; Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples; The values reported in this report are the concentrations in the sub-sample as detected by the instrument, however, the results may not accurately represent the concentrations of the analytes in Tank 50; The low insoluble solids content increases the measurement uncertainty for insoluble species.

  9. Results For The First Quarter 2013 Tank 50 WAC Slurry Sample: Chemical And Radionuclide Contaminants

    SciTech Connect

    Bannochie, C. J.

    2013-05-14

    This report details the chemical and radionuclide contaminant results for the characterization of the 2013 First Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Waste Solidification Engineering (WSE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: SRR WAC targets or limits were met for all analyzed chemical and radioactive contaminates unless noted in this section; {sup 59}Ni, {sup 94}Nb, {sup 247}Cm, {sup 249}Cf, and {sup 251}Cf are above the requested SRR target concentrations. However, they are below the detection limits established by SRNL; Norpar 13 and Isopar L have higher detection limits compared with the Saltstone WAC. The data provided in this report is based upon the concentrations in the sub-sample, and due to the limited solubility in aqueous solution, may not represent the concentrations of the analytes in Tank 50; and, The low insoluble solids content increases the measurement uncertainty for insoluble species.

  10. Method of melting metals to reduce contamination from crucibles

    DOEpatents

    Banker, John G.; Wigginton, Hubert L.

    1977-01-01

    Contamination of metals from crucible materials during melting operations is reduced by coating the interior surface of the crucible with a ceramic non-reactive with the metallic charge and disposing a metal liner formed from a portion of the metallic charge within the coated crucible. The liner protects the ceramic coating during loading of the remainder of the charge and expands against the ceramic coating during heat-up to aid in sintering the coating.

  11. USING ZERO-VALENT METAL NANOPARTICLES TO REMEDIATE ORGANIC CONTAMINANTS

    EPA Science Inventory

    The transport of organic contaminants down the soil profile constitutes a serious threat to the quality of ground water. Zero-valent metals are considered innocuous abiotic agents capable of mediating decontamination processes in terrestrial systems. In this investigation, ze...

  12. RESULTS FOR THE THIRD QUARTER 2007 TANK 50H WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Zeigler, K; Ned Bibler, N

    2008-07-11

    The Saltstone Facility is designed and permitted to immobilize and dispose of low-level radioactive and hazardous liquid waste (salt solution) remaining from the processing of radioactive material at the Savannah River Site. Low activity wastewater streams from the Effluent Treatment Project (ETP), H-Canyon, and the high level waste (HLW) storage tanks, are stored as a mixture in Tank 50H until it can be pumped to the Saltstone Facility for treatment and disposal. Specific waste acceptance criteria (WAC) must be met for the transfer of low-level aqueous waste from Tank 50H to the Saltstone Facility. Low level waste which meets the WAC can be transferred, stored and treated in the Saltstone Production Facility (SPF) for subsequent disposal as saltstone in the Saltstone Disposal Facility (SDF). Waste Solidification Engineering (WSE) has requested through a Technical Task Request (TTR) that the Savannah River National Laboratory (SRNL) measure the concentrations of chemical and radionuclide contaminants listed in the currently approved Saltstone Waste Acceptance Criteria (WAC). A Task Technical and Quality Assurance Plan and Analytical Study Plan has been written for this request. WAC determinations are needed on a quarterly basis for chemical contaminants and every first and third quarter for radioactive contaminants. This memorandum presents the results for the chemical and radionuclide contaminants in the third quarter, from the samples taken from Tank 50 in September, 2007.

  13. A national level assessment of metal contamination in bats.

    PubMed

    Hernout, Béatrice V; Arnold, Kathryn E; McClean, Colin J; Walls, Michael; Baxter, Malcolm; Boxall, Alistair B A

    2016-07-01

    Many populations of bat species across the globe are declining, with chemical contamination one of many potential stressors implicated in these demographic changes. Metals still contaminate a wide range of habitats, but the risks to bats remain poorly understood. This study is the first to present a national scale assessment of toxic metal (Cd, Pb) and essential trace metal (Cu, Zn) concentrations in bats. Metal concentrations in tissues (kidneys, liver, stomach -stomach content, bones and fur) were measured in 193 Pipistrellus sp. in England and Wales using ICP-MS, and compared to critical toxic concentrations for small mammals. The concentrations of metals determined in bat tissues were generally lower than those reported elsewhere. Strong positive associations were found between concentrations in tissues for a given metal (liver and kidneys for Cd, Cu and Pb; stomach and fur and fur and bones for Pb), suggesting recent as well as long term exposure to these contaminants. In addition, positive correlations between concentrations of different metals in the same tissues (Cd and Zn, Cu and Zn, Cd and Pb, Pb and Zn) suggest a co-exposure of metals to bats. Approximately 21% of the bats sampled contained residues of at least one metal at concentrations high enough to elicit toxic effects (associated with kidney damage), or to be above the upper level measured in other mammal species. Pb was found to pose the greatest risk (with 7-11% of the bats containing concentrations of toxicological concern), followed by Cu (4-9%), Zn (0.5-5.2%) and Cd (0%). Our data suggest that leaching of metals into our storage matrix, formaldehyde, may have occurred, especially for Cu. The overall findings suggest that metal contamination is an environmental stressor affecting bat populations, and that further research is needed into the direct links between metal contamination and bat population declines worldwide. PMID:27155931

  14. Some Case Studies on Metal-Microbe Interactions to Remediate Heavy Metals- Contaminated Soils in Korea

    NASA Astrophysics Data System (ADS)

    Chon, Hyo-Taek

    2015-04-01

    Conventional physicochemical technologies to remediate heavy metals-contaminated soil have many problems such as low efficiency, high cost and occurrence of byproducts. Recently bioremediation technology is getting more and more attention. Bioremediation is defined as the use of biological methods to remediate and/or restore the contaminated land. The objectives of bioremediation are to degrade hazardous organic contaminants and to convert hazardous inorganic contaminants to less toxic compounds of safe levels. The use of bioremediation in the treatment of heavy metals in soils is a relatively new concept. Bioremediation using microbes has been developed to remove toxic heavy metals from contaminated soils in laboratory scale to the contaminated field sites. Recently the application of cost-effective and environment-friendly bioremediation technology to the heavy metals-contaminated sites has been gradually realized in Korea. The merits of bioremediation include low cost, natural process, minimal exposure to the contaminants, and minimum amount of equipment. The limitations of bioremediation are length of remediation, long monitoring time, and, sometimes, toxicity of byproducts for especially organic contaminants. From now on, it is necessary to prove applicability of the technologies to contaminated sites and to establish highly effective, low-cost and easy bioremediation technology. Four categories of metal-microbe interactions are generally biosorption, bioreduction, biomineralization and bioleaching. In this paper, some case studies of the above metal-microbe interactions in author's lab which were published recently in domestic and international journals will be introduced and summarized.

  15. Phytoremediation of Metal-Contaminated Soil for Improving Food Safety

    NASA Astrophysics Data System (ADS)

    Shilev, Stefan; Benlloch, Manuel; Dios-Palomares, R.; Sancho, Enrique D.

    The contamination of the environment is a serious problem which provokes great interest in our society and in the whole scientific community. The input of metals into soils has increased during the last few decades as a consequence of different human activities (storage of industrial and municipal wastes, burning of fuels, mining and wastewater treatments, functioning of non-ferrous-metal-producing smelters, etc.). Nowadays, this type of contamination is one of the most serious concerning the chronic toxic effect which it renders on human health and the environment. As a consequence of all these activities, a huge number of toxic metals and metalloids, such as Cu, Zn, Pb, Cd, Hg and As, among many others, have been accumulated in soils, reaching toxic values. Unfortunately, much contaminated land is still in use for crop production, despite the danger that the metal content poses.

  16. Contamination of environment with heavy metals emitted from automotives

    SciTech Connect

    Falahi-Ardakani, A.

    1984-04-01

    Interest has arisen in heavy-metal contamination of the environment, mostly because of potential hazards to the health of animals and human (directly and/or indirectly). High levels of heavy metals in soil, plants, and the atmosphere are often related to industries, highways, chemical dumping, impure chemical fertilizers, and pesticides containing metals. An important source of heavy metals, especially lead, is from the combustion of leaded gasoline used for transportation. Other heavy metals associated with transportation include nickel, which is also added to gasoline and is contained in engine parts, zinc, and cadmium from tires, lubricating oils, and galvanized parts such as fuel tanks.

  17. Process for treating waste water having low concentrations of metallic contaminants

    DOEpatents

    Looney, Brian B; Millings, Margaret R; Nichols, Ralph L; Payne, William L

    2014-12-16

    A process for treating waste water having a low level of metallic contaminants by reducing the toxicity level of metallic contaminants to an acceptable level and subsequently discharging the treated waste water into the environment without removing the treated contaminants.

  18. RESULTS FOR THE SECOND QUARTER 2010 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.; Bibler, N.

    2010-08-04

    This report details the chemical and radionuclide contaminant results for the characterization of the 2010 Second Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC).1 Information from this characterization will be used by Liquid Waste Operations (LWO) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: (1) The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted in this section. (2) The reported detection limits for {sup 94}Nb and {sup 144}Ce are above both the established and requested limits from References 4 and 6. (3) The reported detection limits for {sup 247}Cm and {sup 249}Cf are above the requested limits from Reference 4. However, they are below the limits established in Reference 6. (4) The reported detection limit for Isopar L is greater than the limit from Table 3 of the WAC. (5) A measurable concentration of Norpar 13 is present in the sample. The reported concentration is greater than the requested limit from Table 4 and Attachment 8.2 of the WAC. (6) Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples. The values reported in this memo are the concentrations in the sub-sample as detected by the GC/MS; however, the results may not accurately represent the concentrations of the analytes in Tank 50. (7) The detection limit for isopropanol has been lowered from 0.5 mg/L to 0.25 mg/L{sup 7}. This revised limit now satisfies the limit in Table 4 of the WAC.

  19. RESULTS FOR THE FIRST QUARTER 2010 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.; Bibler, N.

    2010-05-05

    This report details the chemical and radionuclide contaminant results for the characterization of the 2010 First Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Liquid Waste Operations (LWO) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: (1) The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted in this section. (2) The reported detection limit for Isopar L is greater than the limit from Table 3 of the WAC. (3) The reported detection limits for {sup 59}Ni and {sup 94}Nb are above the requested limits from Reference 4. However, they are each below the limits established in Reference 6. (4) The reported detection limit for isopropanol is greater than the requested limit from Table 4 of the WAC. (5) The reported detection limits for 247Cm and 249Cf are above the requested limits from Reference 4. However, they are below the limits established in Reference 6. (6) Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples. The values reported in this memo are the concentrations in the sub-sample as detected by the GC/MS; however, the results may not accurately represent the concentrations of the analytes in Tank 50.

  20. Results For The Fourth Quarter 2012 Tank 50 WAC Slurry Sample: Chemical And Radionuclide Contaminants

    SciTech Connect

    Bannochie, C. J.

    2013-02-05

    This report details the chemical and radionuclide contaminant results for the characterization of the 2012 Fourth Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC).Information from this characterization will be used by Waste Solidification Engineering (WSE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: The concentration of the reported chemical and radioactive contaminants were less than their respective WAC Limits and Targets, unless noted in this section; Norpar 13 and Isopar L have higher detection limits compared with the Saltstone WAC. The data provided in this report is based upon the concentrations in the sub-sample, and due to the limited solubility in aqueous solution, may not represent the concentrations of the analytes in Tank 50; Diisooctyl adipate (or diisooctyl hexanedioate) and 5-methyl-3-hexanol, plasticizers, were measured at 1.30E+00 mg/L and 3.00E+00 mg/L, respectively, in one of two replicate measurements conducted on an at-depth sample. The organic analysis of the at-depth sample was conducted at the request of SRR. These analytes were below the detection limits for the surface sample; and, The low insoluble solids content increases the measurement uncertainty for insoluble species.

  1. RESULTS FOR THE FIRST QUARTER 2012 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Bannochie, C.

    2012-06-06

    This report details the chemical and radionuclide contaminant results for the characterization of the 2012 First Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Waste Solidification Engineering (WSE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this memorandum: (1) The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted in this section; (2) The reported detection limit for {sup 94}Nb is above the requested limit from Reference 2 but below the estimated limit in Reference 3; (3) {sup 247}Cm and {sup 249}Cf are above the requested limits from Reference 2. however, they are below the limits established in Reference 3; (4) The reported detection limit for Norpar 13 is greater than the limit from Table 4 and Attachment 8.2 of the WAC; (5) The reported detection limit for Isopar L is greater than the limit from Table 3 of the WAC; (6) Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples, the values reported in this report are the concentrations in the sub-sample as detected by the instrument; however, the results may not accurately represent the concentrations of the analytes in Tank 50; and (7) The low insoluble solids content increases the measurement uncertainty for insoluble species.

  2. RESULTS FOR THE THIRD QUARTER 2010 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.; Bibler, N.

    2010-12-09

    This report details the chemical and radionuclide contaminant results for the characterization of the 2010 Third Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Liquid Waste Operations (LWO) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: (i) The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted in this section. (ii) The reported detection limits for {sup 94}Nb, {sup 247}Cm and {sup 249}Cf are above the requested limits from Reference 4. However, they are below the limits established in Reference 3. (iii) The reported detection limit for {sup 242m}Am is greater than the requested limit from Attachment 8.4 of the WAC. (iv) The reported detection limit for Isopar L is greater than the limit from Table 3 of the WAC. (v) The reported concentration of Isopropanol is greater than the limit from Table 4 of the WAC. (vi) Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples. The values reported in this memo are the concentrations in the sub-sample as detected by the GC/MS; however, the results may not accurately represent the concentrations of the analytes in Tank 50.

  3. Catalytic extraction processing of contaminated scrap metal

    SciTech Connect

    Griffin, T.P.; Johnston, J.E.; Payea, B.M.; Zeitoon, B.M.

    1995-12-01

    Molten Metal Technology was awarded a contract to demonstrate the applicability of the Catalytic Extraction Process, a proprietary process that could be applied to US DOE`s inventory of low level mixed waste. This paper is a description of that technology, and included within this document are discussions of: (1) Program objectives, (2) Overall technology review, (3) Organic feed conversion to synthetic gas, (4) Metal, halogen, and transuranic recovery, (5) Demonstrations, (6) Design of the prototype facility, and (7) Results.

  4. Contamination and galvanic corrosion in metal chemical-mechanical planarization

    NASA Astrophysics Data System (ADS)

    Zhang, Liming

    Chemical mechanical planarization (CMP) of metals is a critical process in the manufacturing of ultra-large scale integrated (ULSI) circuit devices. The overall success of a CMP process requires minimal particulate and metallic contamination of the structures subjected to CMP. The objective of this study was to investigate alumina particle contamination during tungsten CMP, copper contamination in copper CMP, and galvanic corrosion between metal films and adhesion layers during the final stages of tungsten and copper CMP. Particular attention was paid to the use of short chain organic carboxylic acids in reducing the contamination. Both electrokinetic and uptake measurements showed that citric acid and malonic acid interact with alumina particles by electrostatic as well as specific adsorption forces. Systematic immersion contamination and polishing experiments were carried out to demonstrate the effectiveness of the acids in controlling alumina particulate contamination on wafer surfaces. The difference in the surface cleanliness was interpreted using the electrokinetic data and the calculated interaction energy between alumina particles and the wafer surface. Electrochemical tests showed no severe attack on tungsten films by the acids. Copper ions were found to adsorb onto the silicon dioxide surface, leading to copper contamination levels of upto 1013 atoms/cm 2. The extent of copper contamination was found to depend on the solution pH and the presence of additives such as hydrogen peroxide. Both electrokinetic measurements and immersion contamination experiments showed that citric acid can reduce the copper contamination on the silicon dioxide surface. TiN is more noble than tungsten in the solutions containing oxidants used in tungsten CMP slurries. The most significant corrosion of tungsten was found in the presence of hydrogen peroxide. Copper was found to be more noble than tantalum in acidic solutions. However, in alkaline ammonium hydroxide solutions, the

  5. Coupling bioleaching and electrokinetics to remediate heavy metal contaminated soils.

    PubMed

    Huang, Qingyun; Yu, Zhen; Pang, Ya; Wang, Yueqiang; Cai, Zhihong

    2015-04-01

    In this study, bioleaching was coupled with electrokinetics (BE) to remove heavy metals (Cu, Zn, Cr and Pb) from contaminated soil. For comparison, bioleaching (BL), electrokinetics (EK), and the chemical extraction method were also applied alone to remove the metals. The results showed that the BE method removed more heavy metals from the contaminated soil than the BL method or the EK method alone. The BE method was able to achieve metal solubilization rates of more than 70 % for Cu, Zn and Cr and of more than 40 % for Pb. Within the range of low current densities (<1 mA cm(-2)), higher current density led to more metal removal. However, the metal solubilization rates did not increase with increasing current density when the current density was higher than 1 mA cm(-2). Therefore, it is suggested that bioleaching coupled with electrokinetics can effectively remediate heavy metal-contaminated soils and that preliminary tests should be conducted before field operation to detect the lowest current density for the greatest metal removal. PMID:25680933

  6. Biomonitoring heavy metal contaminations by moss visible parameters.

    PubMed

    Chen, Yang-Er; Cui, Jun-Mei; Yang, Jin-Chuan; Zhang, Zhong-Wei; Yuan, Ming; Song, Chun; Yang, Hui; Liu, Han-Mei; Wang, Chang-Quan; Zhang, Huai-Yu; Zeng, Xian-Yin; Yuan, Shu

    2015-10-15

    Traditional sampling for heavy metal monitoring is a time-consuming and inconvenient method, which also does not indicate contaminants non-invasively and instantaneously. Moss is sensitive to heavy metals and is therefore considered a pollution indicator. However, it is unknown what kind physiological parameters can indicate metal contaminations quickly and non-invasively. Here, we systematically examined the effects of six heavy metals on physiological parameters and photosynthetic activities of two moss species grown in aquatic media or moist soil surface. We suggest that a phenotype with anthocyanin accumulation pattern and chlorosis pattern and two chlorophyll fluorescence parameters with their images can roughly reflect metal species groups, concentrations and differences between the two moss species. In other words, metal contaminations could be roughly estimated visually using the naked eye. Enzymatic and non-enzymatic anti-oxidative abilities and photosynthetic protein contents of Eurhynchium eustegium were higher than those of Taxiphyllum taxirameum, indicating their differential metal tolerance. Neither anti-oxidative abilities nor photosynthetic proteins were found to be ideal indicators. This study provides new ideas to monitor heavy metals rapidly and non-invasively in water or on wetland and moist soil surface. PMID:25919648

  7. Heavy Metals Contamination of Table Salt Consumed in Iran

    PubMed Central

    Cheraghali, Abdol Majid; Kobarfard, Farzad; Faeizy, Noroldin

    2010-01-01

    Lead, cadmium, mercury and arsenic are the most important heavy metals which may cause health risks following consumption of contaminated foods. Table salt is one the mostly used food additive with unique place in food consumption. Although purified table salt is expected to have lower level of contamination, some Iranians still prefer to use rock salt. Use of rock salt for food purposes has been banned by Iranian health authorities. In this study, heavy metal contamination of table salt consumed in Iran has been investigated. One hundred samples of rock and refined table salts were analyzed using atomic absorption spectrophotometeric methods for the presence of toxic heavy metals. The mean concentration of tested tracer metals including Cd, Pb, Hg and As was 0.024, 0.438, 0.021 and 0.094 μg/g, respectively. The concentrations of tested heavy metals were well below the maximum levels set by Codex. However, no statistically significant difference was found between contamination of rock salt and refined salt to heavy metals. PMID:24363718

  8. Spatial analysis of antibiotic resistance along metal contaminated streams.

    PubMed

    Tuckfield, R Cary; McArthur, J Vaun

    2008-05-01

    The spatial pattern of antibiotic resistance in culturable sediment bacteria from four freshwater streams was examined. Previous research suggests that the prevalence of antibiotic resistance may increase in populations via indirect or coselection from heavy metal contamination. Sample bacteria from each stream were grown in media containing one of four antibiotics-tetracycline, chloramphenicol, kanamycin, and streptomycin-at concentrations greater than the minimum inhibitory concentration, plus a control. Bacteria showed high susceptibilities to the former two antibiotics. We summarized the latter two more prevalent (aminoglycoside) resistance responses and ten metals concentrations per sediment sample, by Principal Components Analysis. Respectively, 63 and 58% of the variability was explained in the first principal component of each variable set. We used these multivariate summary metrics [i.e., first principal component (PC) scores] as input measures for exploring the spatial correlation between antibiotic resistance and metal concentration for each stream sampled. Results show a significant and negative correlation between metals PC scores versus aminoglycoside resistance scores and suggest that selection for metal tolerance among sediment bacteria may influence selection for antibiotic resistance differently in sediments than in the water column. Our most important finding comes from geostatistical cross-variogram analysis, which shows that increasing metal concentration scores are spatially associated with decreasing aminoglycoside resistance scores--a negative correlation, but holds for contaminated streams only. We suspect our field results are influenced by metal bioavailability in the sediments and by a contaminant promoted interaction or "cocktail effect" from complex combinations of pollution mediated selection agents. PMID:17899247

  9. RESTORATION OF METAL CONTAMINATED SOILS USING BIOSOLIDS

    EPA Science Inventory

    Biosolids in combination with different types of limestone have been applied to metal mine tailings in Bunker Hill, ID, Leadville, Co, Joplin, MO and Tar Creek, OK. For each of these sites, tailings were unable to support a vegetative cover prior to amendment addition. Elevated...

  10. Removal of metals by sorghum plants from contaminated land.

    PubMed

    Zhuang, Ping; Shu, Wensheng; Li, Zhian; Liao, Bin; Li, Jintian; Shao, Jingsong

    2009-01-01

    The growth of high biomass crops facilitated by optimal of agronomic practices has been considered as an alternative to phytoremediation of soils contaminated by heavy metals. A field trial was carried out to evaluate the phytoextraction efficiency of heavy metals by three varieties of sweet sorghum (Sorghum biocolor L.), a high biomass energy plant. Ethylene diamine tetraacetate (EDTA), ammonium nitrate (NH4NO3) and ammonium sulphate ((NH4)2SO4) were tested for their abilities to enhance the removal of heavy metals Pb, Cd, Zn, and Cu by sweet sorghum from a contaminated agricultural soil. Sorghum plants always achieved the greatest removal of Pb by leaves and the greatest removal of Cd, Zn and Cu by stems. There was no significant difference among the Keller, Rio and Mray varieties of sweet sorghums in accumulating heavy metals. EDTA treatment was more efficient than ammonium nitrate and ammonium sulphate in promoting Pb accumulation in sweet sorghum from the contaminated agricultural soil. The application of ammonium nitrate and ammonium sulphate increased the accumulation of both Zn and Cd in roots of sorghum plants. Results from this study suggest that cropping of sorghum plants facilitated by agronomic practices may be a sustainable technique for partial decontamination of heavy metal contaminated soils. PMID:19999999

  11. Phytoremediation of heavy metal contaminated soil by Jatropha curcas.

    PubMed

    Chang, Fang-Chih; Ko, Chun-Han; Tsai, Ming-Jer; Wang, Ya-Nang; Chung, Chin-Yi

    2014-12-01

    This study employed Jatropha curcas (bioenergy crop plant) to assist in the removal of heavy metals from contaminated field soils. Analyses were conducted on the concentrations of the individual metals in the soil and in the plants, and their differences over the growth periods of the plants were determined. The calculation of plant biomass after 2 years yielded the total amount of each metal that was removed from the soil. In terms of the absorption of heavy metal contaminants by the roots and their transfer to aerial plant parts, Cd, Ni, and Zn exhibited the greatest ease of absorption, whereas Cu, Cr, and Pb interacted strongly with the root cells and remained in the roots of the plants. J. curcas showed the best absorption capability for Cd, Cr, Ni, and Zn. This study pioneered the concept of combining both bioremediation and afforestation by J. curcas, demonstrated at a field scale. PMID:25236867

  12. RESULTS FOR THE FIRST QUARTER 2009 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.; Diprete, C.; Bibler, N.

    2009-10-06

    This report details the chemical and radionuclide contaminant results for the characterization of the 2009 First Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Liquid Waste Operations (LWO) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: (1) The concentrations of the chemical and radioactive contaminants were all less than their respective WAC Targets or Limits except for Am-242m. (2) The radionuclide Am-242m was not detected; however, its detection limit is above the WAC Target given in Attachment 8.4. The higher detection limit was expected based on current analytical capabilities as stated in the Task Technical and Quality Assurance Plan (TTQAP). (3) The reported detection limit of isopropanol was lower than its WAC Limit for accident analysis but higher than its WAC concentration given in Table 4 for vault flammability. The higher detection limit was expected based on current analytical capabilities and is documented in the Task Technical and Quality Assurance Plan (TTQAP). (4) The reported detection limit for Isopar L is lower than its WAC limit for accident analysis in Appendix 8.1 but higher than its WAC concentration given in Table 3 in reference to vault flammability. The higher detection limit was expected based on current analytical capabilities as stated in the Task Technical and Quality Assurance Plan (TTQAP). (5) Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples. The values reported in this memo are the concentrations in the sub-sample as detected by the GC/MS; however, the results may not accurately

  13. RESULTS FOR THE FIRST QUARTER 2011 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.

    2011-06-15

    This report details the chemical and radionuclide contaminant results for the characterization of the 2011 First Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Waste Solidification Engineering (WSE) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. The following conclusions are drawn from the analytical results provided in this report: (1) The concentrations of the reported chemical and radioactive contaminants were less than their respective WAC targets or limits unless noted in this section; (2) The reported detection limit for {sup 59}Ni is above both the requested limits from Reference 2 and the established limits in Reference 3; (3) The reported detection limit for {sup 94}Nb is above the requested limit from Reference 2; however, it is below the established limits in Reference 3. This is a change from previously reported results; (4) The reported concentration of {sup 242m}Am is above the target in Listed in Attachment 8.4 of the Saltstone WAC. This is a change from the previously reported results; (5) {sup 247}Cm and {sup 249}Cf are above the requested limits from Reference 2. However, they are below the limits established in Reference 3; (6) The reported detection limit for Norpar 13 is greater than the limit from Table 4 and Attachment 8.2 of the WAC; (7) The reported detection limit for Isopar L is greater than the limit from Table 3 of the WAC; and (8) Isopar L and Norpar 13 have limited solubility in aqueous solutions making it difficult to obtain consistent and reliable sub-samples. The values reported in this memo are the concentrations in the sub-sample as detected by the instrument; however, the results may not accurately represent the concentrations of the analytes in Tank

  14. Benzene contamination at a metal plating facility

    NASA Astrophysics Data System (ADS)

    Memon, B. A.; Burston, M. R.

    2005-08-01

    A metal plating facility in central Kentucky was required to complete a RCRA Facility Investigation to address a number of Solid Waste Management Units at the site. Twenty monitoring wells were installed at the facility. Ground water from the wells was sampled for total and dissolved metals, polychlorinated biphenyls, acid extractable compounds, base neutral compounds, and volatile organic compounds. Unexpectedly, relatively large concentrations of benzene, up to 120 μg/l, were detected in samples from some of the wells, including wells that should have been hydraulically upgradient from the facility. As a result of the detection of benzene, the facility completed an investigation to identify the source. A nearby facility had completed a gasoline underground storage tank (UST) closure at about the time of the installation of the 20 wells. Reportedly the UST had small holes when removed. Three potential pathways of migration (a ditch, sanitary sewer, and a sink hole) from the nearby facility to the metal-plating facility and residual soils with very large concentrations of benzene, toluene, ethylbenzene, and xylenes have been identified.

  15. Vertical column hydroclassification of metal-contaminated soils.

    PubMed

    Williford, C W; Li, Z; Wang, Z; Bricka, R M

    1999-04-23

    The purpose of this work was to reduce soil volumes requiring aggressive treatment. A second purpose was to determine differences in separation due to distinct forms of the metal contamination and soil texture. The objectives were to apply hydroclassification and find mass and metal-contaminant distribution of four soils contaminated with heavy metals from firing ranges, a small arms incinerator, and an electroplating operation. The soils were slurried in water, sieved, and exposed to upward flowing water to separate the soil particles into four nominal size ranges. The popping furnace soil exhibited substantial lead among all particle size fractions. The firing range soils exhibited bimodal distributions. The electroplating soil exhibited a strong concentration of metals toward the <63 microm fraction. Attrition scrubbing moderately improved the enrichment of metals in several fractions. Extraction revealed the lead and chromium in the electroplating soil to be relatively immobile. These results suggest metal distributions are influenced by the different mechanisms of introduction into the soil. They also help to predict performance of processing options such as sieving hydroclassification and attrition scrubbing. PMID:10379028

  16. Removal of trace metal contaminants from potable water by electrocoagulation.

    PubMed

    Heffron, Joe; Marhefke, Matt; Mayer, Brooke K

    2016-01-01

    This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more effective at removing nickel and cadmium, while at pH 8.5, iron electrodes were more effective for these metals. Regardless of electrode, cadmium and nickel removal efficiencies were higher at pH 8.5 than at pH 6.5. Post-EC treatment using membrane filtration (0.45 μm) enhanced contaminant removal for all metals but nickel. With the exception of lead, all metals exhibited poorer removal efficiencies as the ionic strength of the background electrolyte increased, particularly in the very high-solids synthetic groundwaters. Residual aluminum concentrations were lowest at pH 6.5, while iron residuals were lowest in low ionic strength waters. Both aluminum and iron residuals required post-treatment filtration to meet drinking water standards. EC with post-treatment filtration appears to effectively remove trace metal contaminants to potable water standards, but both reactor and source water parameters critically impact removal efficiency. PMID:27324564

  17. Removal of trace metal contaminants from potable water by electrocoagulation

    NASA Astrophysics Data System (ADS)

    Heffron, Joe; Marhefke, Matt; Mayer, Brooke K.

    2016-06-01

    This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more effective at removing nickel and cadmium, while at pH 8.5, iron electrodes were more effective for these metals. Regardless of electrode, cadmium and nickel removal efficiencies were higher at pH 8.5 than at pH 6.5. Post-EC treatment using membrane filtration (0.45 μm) enhanced contaminant removal for all metals but nickel. With the exception of lead, all metals exhibited poorer removal efficiencies as the ionic strength of the background electrolyte increased, particularly in the very high-solids synthetic groundwaters. Residual aluminum concentrations were lowest at pH 6.5, while iron residuals were lowest in low ionic strength waters. Both aluminum and iron residuals required post-treatment filtration to meet drinking water standards. EC with post-treatment filtration appears to effectively remove trace metal contaminants to potable water standards, but both reactor and source water parameters critically impact removal efficiency.

  18. Removal of trace metal contaminants from potable water by electrocoagulation

    PubMed Central

    Heffron, Joe; Marhefke, Matt; Mayer, Brooke K.

    2016-01-01

    This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more effective at removing nickel and cadmium, while at pH 8.5, iron electrodes were more effective for these metals. Regardless of electrode, cadmium and nickel removal efficiencies were higher at pH 8.5 than at pH 6.5. Post-EC treatment using membrane filtration (0.45 μm) enhanced contaminant removal for all metals but nickel. With the exception of lead, all metals exhibited poorer removal efficiencies as the ionic strength of the background electrolyte increased, particularly in the very high-solids synthetic groundwaters. Residual aluminum concentrations were lowest at pH 6.5, while iron residuals were lowest in low ionic strength waters. Both aluminum and iron residuals required post-treatment filtration to meet drinking water standards. EC with post-treatment filtration appears to effectively remove trace metal contaminants to potable water standards, but both reactor and source water parameters critically impact removal efficiency. PMID:27324564

  19. ACID EXTRACTION TREATMENT SYSTEM FOR TREATMENT OF METAL CONTAMINATED SOILS

    EPA Science Inventory

    The Acid Extraction Treatment System (AETS) reduces the concentrations and/or leachability of heavy metals in contaminated soils so the soil can be returned to the site from which it originated. he objective of the project was to determine the effectiveness and commercial viabili...

  20. THE IMPORTANCE OF BIOAVAILABILITY IN REMEDIATION OF METAL CONTAMINATED SOILS

    EPA Science Inventory

    Reduction in exposure to soil metal contamination has typically been accomplished by soil removal and off site disposal, by covering, or by diluting with uncontaminated soil. Cost, logistical concerns, and regulatory requirements associated with excavation and disposal or ex-situ...

  1. HEAVY METAL CONTAMINATION IN THE TAIMYR PENINSULA, SIBERIAN ARCTIC

    EPA Science Inventory

    The Taimyr Peninsula is directly north of the world's largest heavy metal smelting complex (Norilsk, Russia). Despite this proximity, there has been little research to examine the extent of contamination of the Taimyr Peninsula, primarily because of the remoteness of this area. W...

  2. Plant productivity and heavy metal contamination

    SciTech Connect

    Guidi, G.V.; Petruzzelli, G.; Vallini, G.; Pera, A.

    1990-06-01

    This article describes the potential for use of composts from green waste and from municipal solid wastes for agricultural use in Italy. The accumulation of heavy metals in compost-amended soils and crops was evaluated and the influence of these composts on plant productivity was studied. Green compost was obtained from vegetable organic residues; municipal solid waste derived compost was obtained from the aerobic biostabilization of a mixture of the organic biodegradable fraction of municipal solid waste and sewage sludge. The two composts had good chemical characteristics and their use caused no pollution to soil and plants. The overall fertilizing effect was higher for green compost even though green compost and municipal solid waste derived compost had similar contents of primary elements of fertility.

  3. Electrokinetic treatment of an agricultural soil contaminated with heavy metals.

    PubMed

    Figueroa, Arylein; Cameselle, Claudio; Gouveia, Susana; Hansen, Henrik K

    2016-07-28

    The high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co(+2), Zn(+2), Cd(+2), Cu(+2), Cr(VI), Pb(+2) and Hg(+2). The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen. PMID:27127923

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

    USGS Publications Warehouse

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

    2015-01-01

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

  5. Magnetic mineralogy of heavy metals-contaminated soils

    NASA Astrophysics Data System (ADS)

    Shenggao, L.

    2012-04-01

    Soils around mine and in urban areas are often contaminated by heavy metals derived from industrial and human activities [1, 2]. These contaminated soils are often characterized by a magnetic enhancement on topsoils. Many studies demonstrated that there are significant correlations between heavy metals and various magnetic parameters in contaminated soils, indicating a strong affinity of heavy metals to magnetic minerals. The magnetic particles in contaminated soils were separated by a magnetic separation technique. The rock magnetism, XRD, field emission scanning electron microscopy equiped with an energy-dispersive X-ray analyzer (FESEM/EDX) were used to characterize their magnetic mineralogy. Results of XRD analysis indicated that the magnetic particles separated from heavy metal-contaminated soils are composed of quartz, magnetite, and hematite. Based on the X-ray diffraction peak intensity, the Fe3O4 was identified as the predominant magnetic mineral phase. The high-temperature magnetization (Ms-T) curves of magnetic particles extracted from contaminated soils show a sharp Ms decrease at about 580C (the Curie temperature of magnetite), suggesting that magnetite is the dominant magnetic carrier. The hysteresis loops of contaminated soils are closed at about 100-200 mT which is consistent with the presence of a dominant ferrimagnetic mineral phase. The FESEM analysis showed a great variety of shapes of magnetic particles in contaminated soils. The most common morphology are observed in the form of spherules, with the sizes ranging from 20 to 100 um. The chemical composition of magnetic particles consist mainly of Fe, Si, Al, and Ca with minor heavy metal elements (Cu, Zn, Hg, and Cr). The semi-quantitative Fe content identified by FESEM/EDX ranged from 40 to 90%. Combined studies of rock magnetism, XRD, and FESEM/EDX indicated that magnetic mineral phases responsible for the magnetic enhancement of contaminated soils are anthropogenic origin which are coarse

  6. Electroosmotic flow behaviour of metal contaminated expansive soil.

    PubMed

    Sivapullaiah, P V; Prakash, B S Nagendra

    2007-05-17

    It is important to study the flow behaviour through soil during electrokinetic extraction of contaminants to understand their removal mechanism. The flow through the expansive soil containing montmorillonite is monitored during laboratory electrokinetic extraction of heavy metal contaminants. The permeability of soil, which increases due to the presence of contaminants, is further enhanced during electrokinetic extraction of contaminants due to osmotic permeability. The variations in flow rates through the soil while the extracting fluid is changed to dilute acetic acid (used to control the increase of pH) and EDTA solution (used to desorb the metal ions from soil) are studied. The trends of removal of contaminants vis-a-vis the changes in the flow through the soil during different phases of electrokinetic extraction are established. Chromium ions are removed by flushing of water through the soil and increased osmotic flow is beneficial. Removal of iron ions is enhanced by induced osmotic flow and desorption of ions by electrokinetic processes. PMID:17276001

  7. Disintegration and size reduction of slags and metals after melt refining of contaminated metallic wastes

    SciTech Connect

    Heshmatpour, B.; Copeland, G.L.; Heestand, R.L.

    1981-04-01

    Melting under an oxidizing slag is an attractive method of decontaminating and reducing the volume of radioactively contaminated metal scrap. The contaminants are concentrated in a relatively small volume of slag, which leaves the metal essentially clean. A potential method of permanently disposing of the resulting slags (and metals if necessary) is emplacing them into deep shale by grout hydrofracture. Suspension in grout mixtures requires that the slag and metal be granular. The feasibility of size-reducing slags and disintegrating metals and subsequently incorporating both into grout mixtures was demonstrated. Various types of slags were crushed with a small jaw crusher into particles smaller than 3 mm. Several metals were also melted and water-blasted into coarse metal powder or shot ranging in size from 0.05 to 3 mm. A simple low-pressure water atomizer having a multiple nozzle with a converging-line jet stream was developed and used for this purpose. No significant slag dust and steam were generated during slag crushing and liquid-metal water-blasting tests, indicating that contamination can be well contained within the system. The crushed slags and the coarse metal powders were suspendable in group fluids, which indicates probable disposability by shale hydrofracture. The granulation of slags and metals facilitates their containment, transport, and storage.

  8. RESULTS FOR THE THIRD QUARTER 2009 TANK 50 WAC SLURRY SAMPLE: CHEMICAL AND RADIONUCLIDE CONTAMINANT RESULTS

    SciTech Connect

    Reigel, M.; Diprete, C.; Bibler, N.

    2009-11-13

    This report details the chemical and radionuclide contaminant results for the characterization of the 2009 Third Quarter sampling of Tank 50 for the Saltstone Waste Acceptance Criteria (WAC). Information from this characterization will be used by Liquid Waste Operations (LWO) to support the transfer of low-level aqueous waste from Tank 50 to the Salt Feed Tank in the Saltstone Facility in Z-Area, where the waste will be immobilized. This information is also used to update the Tank 50 Waste Characterization System. Recently, a review of the radionuclide inventory in Saltstone Vaults 1 and 4 identified several additional radionuclides, not currently in the WAC, which require quantification ({sup 40}K, {sup 108m}Ag, {sup 133}Ba, {sup 207}Bi, {sup 227}Ac, {sup 228}Ra, {sup 228}Th, {sup 231}Pa, {sup 247}Cm, {sup 249}Cf, {sup 251}Cf). In addition, several of the radionuclides previously reported with minimum detection limits below the requirements listed in the WAC required analysis with reduced detection limits to support future inventory reporting requirements ({sup 22}Na, {sup 26}Al, {sup 59}Ni, {sup 94}Nb, {sup 106}Ru, {sup 144}Ce, {sup 152}Eu, {sup 155}Eu, {sup 226}Ra). This added scope was formally requested in a revision to the standing Technical Task Request for CY2009 Saltstone support and is further discussed in several supporting documents. The following conclusions are drawn from the analytical results provided in this report: (1) The concentrations of the reported chemical and radioactive contaminants are less than their respective WAC targets or limits unless noted in this section. (2) The reported detection limits for {sup 59}Ni, {sup 94}Nb, {sup 247}Cm, and {sup 249}Cf are above the limits requested by LWO; however, they are below the achievable limits established by Analytical Development (AD). (3) The reported detection limit of isopropanol is lower than its WAC Limit for accident analysis in Appendix 8.1, but higher than its WAC concentration given in

  9. Humus-assisted cleaning of heavy metal contaminated soils

    NASA Astrophysics Data System (ADS)

    Borggaard, Ole K.; Rasmussen, Signe B.

    2016-04-01

    Contamination of soils with non-degradable heavy metals (HMs) because of human acticities is globally a serious problem threatening human health and ecosystem functioning. To avoid negative effects, HMs must be removed either on-site by plant uptake (phytoremediation) or off-site by extraction (soil washing). In both strategies, HM solubility must be augmented by means of a strong ligand (complexant). Often polycarboxylates such as EDTA and NTA are used but these ligands are toxic, synthetic (non-natural) and may promote HM leaching. Instead naturally occurring soluble humic substances (HS) were tested as means for cleaning HM contaminated soils; HS samples from beech and spruce litter, compost percolate and processed cow slurry were tested. Various long-term HM contaminated soils were extracted with solutions of EDTA, NTA or HS at different pH by single-step and multiple-step extraction mode. The results showed that each of the three complexant types increased HM solubility but the pH-dependent HM extraction efficiency decreased in the order: EDTA ≈ NTA > HS. However, the naturally occurring HS seems suitable for cleaning As, Cd, Cu and Zn contaminated soils both in relation to phytoremediation of moderately contaminated soils and washing of strongly contaminated soils. On the other hand, HS was found unsuited as cleaning agent for Pb polluted calcareous soils. If future field experiments confirm these laboratory results, we have a new cheap and environmentally friendly method for solving a great pollution problem, i.e. cleaning of heavy metal contaminated soils. In addition, humic substances possess additional benefits such as improving soil structure and stimulating microbial activity.

  10. Wetland plants as indicators of heavy metal contamination.

    PubMed

    Phillips, D P; Human, L R D; Adams, J B

    2015-03-15

    In this study metal accumulating abilities of three emergent macrophytes (Phragmites australis, Typha capensis and Spartina maritima) were investigated in the urbanised Swartkops Estuary. Plants and sediment samples were collected at seven sites along the banks of the main channel and in adjacent canals. Sediments and plant organs were analysed, by means of atomic absorption spectrometry, for four elements (Cd, Cu, Pb, and Zn). Metal concentrations in the sediments of adjacent canals were found to be substantially higher than those at sites along the banks of the estuary. These differences were reflected in the plant organs for Pb and Zn, but not for Cu and Cd. All three species exhibited significantly higher concentrations of metals in their roots. These species are therefore suitable for use as indicators of the presence and level of heavy metal contaminants in estuaries. PMID:25599629

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

    PubMed

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

    2015-08-15

    A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability. PMID:26140749

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

    SciTech Connect

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

    2009-01-06

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

  13. Feasibility of re-melting NORM-contaminated scrap metal

    SciTech Connect

    Winters, S. J.; Smith, K. P.

    1999-10-26

    Naturally occurring radioactive materials (NORM) sometimes accumulate inside pieces of equipment associated with oil and gas production and processing activities. Typically, the NORM accumulates when radium that is present in solution in produced water precipitates out in scale and sludge deposits. Scrap equipment containing residual quantities of these NORM-bearing scales and sludges can present a waste management problem if the radium concentrations exceed regulatory limits or activate the alarms on radiation screening devices installed at most scrap metal recycling facilities. Although NORM-contaminated scrap metal currently is not disposed of by re-melting, this form of recycling could present a viable disposition option for this waste stream. Studies indicate that re-melting NORM-contaminated scrap metal is a viable recycling option from a risk-based perspective. However, a myriad of economic, regulatory, and policy issues have caused the recyclers to turn away virtually all radioactive scrap metal. Until these issues can be resolved, re-melting of the petroleum industry's NORM-impacted scrap metal is unlikely to be a widespread practice. This paper summarizes the issues associated with re-melting radioactive scrap so that the petroleum industry and its regulators will understand the obstacles. This paper was prepared as part of a report being prepared by the Interstate Oil and Gas Compact Commission's NORM Subcommittee.

  14. Biosorption of metal contaminants using immobilized biomass--Field studies

    SciTech Connect

    Jeffers, T.H.; Bennett, P.G.; Corwin, R.R.

    1993-01-01

    The US Bureau of Mines has developed porous beads containing immobilized biological materials such as sphagnum peat moss for extracting metal contaminants from waste waters. The beads, designated as BIO-FIX beads, have removed toxic metals from over 100 waters in laboratory tests. These waters include acid mine drainage (AMD) water from mining sites, metallurgical and chemical industry waste water, and contaminated ground water. Following the laboratory studies, cooperative field tests were conducted to evaluate the metal adsorption properties of the beads in column and low-maintenance circuits, determine bead stability in varied climatic situations, and demonstrate the beads' potential as a viable waste water treatment technique. Field results indicated that BIO-FIX beads readily adsorbed cadmium, lead, and other toxic metals from dilute waters; effluents frequently met drinking water standards and other discharge criteria. The beads exhibited excellent handling characteristics in both column and low-maintenance circuits, and continued to extract metal ions after repeated loading-elution cycles. Based on laboratory and field data, cost evaluations for using BIO-FIX technology to treat two AMD waters were prepared. Operating costs for BIO-FIX treatment, which ranged from $1.40 to $2.30 per 1,000 gal of water treated, were comparable with chemical precipitation costs.

  15. Bead and Process for Removing Dissolved Metal Contaminants

    SciTech Connect

    Summers, Bobby L., Jr.; Bennett, Karen L.; Foster, Scott A.

    2005-01-18

    A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly (carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making metal-ion sorbing beads is provided, comprising combining activated carbon, and binder solution (preferably in a pin mixer where it is whipped), forming wet beads, and heating and drying the beads. The binder solution is preferably poly(acrylic acid) and glycerol dissolved in water and the wet beads formed from such binder solution are preferably heated and crosslinked in a convection oven.

  16. Evaluation of metal and microbial contamination in botanical supplements.

    PubMed

    Raman, Priyadarshini; Patino, Lina C; Nair, Muraleedharan G

    2004-12-29

    The sale of botanical dietary supplements in the United States is on the rise. However, limited studies have been conducted on the safety of these supplements. There are reports on the presence of undesired metals in some of the botanical dietary supplements. In this study, echinacea, garlic, ginkgo, ginseng, grape seed extract, kava kava, saw palmetto, and St. John's wort supplements manufactured by Nature's Way, Meijer, GNC, Nutrilite, Solaray, Sundown and Natrol, have been analyzed for lead, mercury, cadmium, arsenic, uranium, chromium, vanadium, copper, zinc, molybdenum, palladium, tin, antimony, thallium, and tungsten using inductively coupled plasma mass spectrometry. All samples were devoid of mercury contamination. Results indicated that the botanical supplements analyzed did not contain unacceptable concentrations of these metals. These supplements were also evaluated for microbial contamination, and most samples analyzed showed the presence of bacteria or fungi or both. Microbes were not counted nor were microbial counts determined in these samples. PMID:15612762

  17. Barnacles as biomonitors of metal contamination in coastal waters

    NASA Astrophysics Data System (ADS)

    Reis, Pedro A.; Salgado, Maria Antónia; Vasconcelos, Vitor

    2011-07-01

    The use of barnacles as biomonitors of metal contamination in coastal waters worldwide is reviewed as a critique compilation of the reported studies and presents resume-tables of available data for future reference. The barnacle body reflects both short and long-term metal level environmental variations and the metal bioaccumulation occurs mainly in their granules (relatively inactive pools). The barnacle body is considered as good biomonitoring material and different barnacle species could bioaccumulate metal concentration ranges of 40-153,000 μg/g of Zn, 20-22,230 μg/g de Fe, 1.5-21,800 μg/g of Cu, 5.9-4742 μg/g of Mn, 0.1-1000 μg/g of Pb, 0.7-330 μg/g of Cd, 0.4-99 μg/g of Ni and 0.2-49 μg/g of Cr. However, as the plates ('shells') of barnacle exoskeletons can be affected by metal levels in coastal waters, mainly in their composition and morphology, they are not considered good biomonitoring material. Despite this, the use of a specific barnacle species or group of species in a specific region must firstly be carefully validated and the interpretation of the contaminant bioaccumulation levels should involve specific environmental variations of the region, physiological parameters of the barnacle species and the relationship between the potential toxicity of the contaminant for the environment and their significance for the barnacle species. Barnacles, particularly a widespread cosmopolitan species such as Amphibalanus amphitrite, have a great potential as biomonitors of anthropogenic contamination in coastal waters and have been used worldwide, including Europe (United Kingdom, Turkey, Poland, Croatia, Spain and Portugal), Asia (India and China), Oceania (Australia), North America (Florida, Massachusetts and Mexico) and South America (Brazil). The use of barnacle species as biomonitors of metal contamination in coastal waters is considered an important and valuable tool to evaluate and predict the ecological quality of an ecosystem.

  18. Chemical methods and phytoremediation of soil contaminated with heavy metals.

    PubMed

    Chen, H M; Zheng, C R; Tu, C; Shen, Z G

    2000-07-01

    The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavy metal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavy metal-contaminated soil could be remediated with a combination of chemical treatments and plants. PMID:10819205

  19. Human impact on fluvial sediments: distinguishing regional and local sources of heavy metals contamination

    NASA Astrophysics Data System (ADS)

    Novakova, T.; Matys Grygar, T.; Bábek, O.; Faměra, M.; Mihaljevič, M.; Strnad, L.

    2012-04-01

    Industrial pollution can provide a useful tool to study spatiotemporal distribution of modern floodplain sediments, trace their provenance, and allow their dating. Regional contamination of southern Moravia (the south-eastern part of the Czech Republic) by heavy metals during the 20th century was determined in fluvial sediments of the Morava River by means of enrichment factors. The influence of local sources and sampling sites heterogeneity were studied in overbank fines with different lithology and facies. For this purpose, samples were obtained from hand-drilled cores from regulated channel banks, with well-defined local sources of contamination (factories in Zlín and Otrokovice) and also from near naturally inundated floodplains in two nature protected areas (at 30 km distance). The analyses were performed by X-ray fluorescence spectroscopy (ED XRF), ICP MS (EDXRF samples calibration, 206Pb/207Pb ratio), magnetic susceptibility, cation exchange capacity (CEC), and 137Cs and 210Pb activities. Enrichment factors (EF) of heavy metals (Pb, Zn, Cu and Cr) and magnetic susceptibility of overbank fines in near-naturally (near annually) inundated areas allowed us to reconstruct historical contamination by heavy metals in the entire study area independently on lithofacies. Measured lithological background values were then used for calculation of EFs in the channel sediments and in floodplain sediments deposited within narrow part of a former floodplain which is now reduced to about one quarter of its original width by flood defences. Sediments from regulated channel banks were found stratigraphically and lithologically "erratic", unreliable for quantification of regional contamination due to a high variability of sedimentary environment. On the other hand, these sediments are very sensitive to the nearby local sources of heavy metals. For a practical work one must first choose whether large scale, i.e. a really averaged regional contamination should be reconstructed

  20. Residual metallic contamination of transferred chemical vapor deposited graphene.

    PubMed

    Lupina, Grzegorz; Kitzmann, Julia; Costina, Ioan; Lukosius, Mindaugas; Wenger, Christian; Wolff, Andre; Vaziri, Sam; Östling, Mikael; Pasternak, Iwona; Krajewska, Aleksandra; Strupinski, Wlodek; Kataria, Satender; Gahoi, Amit; Lemme, Max C; Ruhl, Guenther; Zoth, Guenther; Luxenhofer, Oliver; Mehr, Wolfgang

    2015-05-26

    Integration of graphene with Si microelectronics is very appealing by offering a potentially broad range of new functionalities. New materials to be integrated with the Si platform must conform to stringent purity standards. Here, we investigate graphene layers grown on copper foils by chemical vapor deposition and transferred to silicon wafers by wet etching and electrochemical delamination methods with respect to residual submonolayer metallic contaminations. Regardless of the transfer method and associated cleaning scheme, time-of-flight secondary ion mass spectrometry and total reflection X-ray fluorescence measurements indicate that the graphene sheets are contaminated with residual metals (copper, iron) with a concentration exceeding 10(13) atoms/cm(2). These metal impurities appear to be partially mobile upon thermal treatment, as shown by depth profiling and reduction of the minority charge carrier diffusion length in the silicon substrate. As residual metallic impurities can significantly alter electronic and electrochemical properties of graphene and can severely impede the process of integration with silicon microelectronics, these results reveal that further progress in synthesis, handling, and cleaning of graphene is required to advance electronic and optoelectronic applications. PMID:25853630

  1. Heavy metal contamination in the Delhi segment of Yamuna basin.

    PubMed

    Sehgal, Meena; Garg, Ankur; Suresh, R; Dagar, Priya

    2012-01-01

    Concentration of heavy metals (Cd, Ni, Zn, Fe, Cu, Mn, Pb, Cr, Hg and As) in the waters of River Yamuna and in the soil of agricultural fields along its course in Delhi are reported from 13 sites, spread through the Delhi stretch of Yamuna, starting from the Wazirabad barrage till the Okhla barrage. Varying concentration of heavy metals was found. Peaks were observed in samples collected downstream of Wazirabad and Okhla barrage, indicating the anthropogenic nature of the contamination. The Wazirabad section of the river receives wastewater from Najafgarh and its supplementary drains, whereas the Shahdara drain releases its pollution load upstream of the Okhla barrage. Average heavy metal concentration at different locations in the river water varied in the order of Fe>Cr>Mn>Zn>Pb>Cu>Ni>Hg>As>Cd. The river basin soil shows higher level of contamination with lesser variation than the water samples among sampling locations, thereby suggesting deposition over long periods of time through the processes of adsorption and absorption. The average heavy metal concentration at different locations in soil varied in the order of Fe>Mn>Zn>Cr>Pb>Ni>Hg>Cu>As>Cd. PMID:21505769

  2. Electrokinetic In Situ Treatment of Metal-Contaminated Soil

    NASA Technical Reports Server (NTRS)

    Quinn, Jacqueline; Clausen, Christian A., III; Geiger, Cherie; Reinhart, Debra

    2004-01-01

    An electrokinetic technique has been developed as a means of in situ remediation of soils, sludges, and sediments that are contaminated with heavy metals. Examples of common metal contaminants that can be removed by this technique include cadmium, chromium, zinc, lead, mercury, and radionuclides. Some organic contaminants can also be removed by this technique. In the electrokinetic technique, a low-intensity direct current is applied between electrodes that have been implanted in the ground on each side of a contaminated soil mass. The electric current causes electro-osmosis and migration of ions, thereby moving aqueous-phase subsurface contaminants from one electrode to the other. The half reaction at the anode yields H+, thereby generating an acid front that travels from the anode toward the cathode. As this acid front passes through a given location, the local increase in acidity increases the solubility of cations that were previously adsorbed on soil particles. Ions are transported towards one electrode or the other which one depending on their respective electric charges. Upon arrival at the electrodes, the ionic contaminants can be allowed to become deposited on the electrodes or can be extracted to a recovery system. Surfactants and other reagents can be introduced at the electrodes to enhance rates of removal of contaminants. Placements of electrodes and concentrations and rates of pumping of reagents can be adjusted to maximize efficiency. The basic concept of electrokinetic treatment of soil is not new. What is new here are some of the details of application and the utilization of this technique as an alternative to other techniques (e.g., flushing or bioremediation) that are not suitable for treating soils of low hydraulic conductivity. Another novel aspect is the use of this technique as a less expensive alternative to excavation: The cost advantage over excavation is especially large in settings in which contaminated soil lies near and/or under

  3. Microbial recovery of metals from spent coal liquefaction catalysts. Quarterly report, July--September 1993

    SciTech Connect

    Sandbeck, K.A.; Joffe, P.M.

    1993-12-31

    The project objectives outlined in the previous reports involved defining conditions and cultures best suited to achieve the most effective metal release from spent coal liquefaction catalysts by microbial processes. The work initiated in the first quarter of 1993 was continued and expanded using solvent extraction systems defined by the multiple solvent tests used for washing the catalysts. To reduce the number of solvent systems the data were examined and two solvents selected for continued testing. The two solvent systems which were chosen and have been employed are the isopropanol and a tetrahydrofuran (THF) extractive solvents. In the present simplified extractive system, the catalysts are washed with the solvent with simple agitation to prevent catalyst breakage. Studies on the effect of catalyst surface area will be continued in conjunction with the progressive development of the optimized microbial metal releasing system. Thermophilic cultures (Bacillus stearothermophilus and Metallosphaera sedula) are being grown at 60 C for initial metal releasing studies. Since THF has proven to be a superior solvent system as judged by metal release, research has concentrated on using THF as the solvent system allowing work to proceed rapidly. However, additional work will still be directed toward defining any solvent system superior to THF in terms of aiding microbiological release of metals and economic feasibility. These studies include measurements of metal release at various catalyst-media ratios for both the tetrahydrofuran and isopropanol washed catalysts. The importance of the catalyst-media ratios is assuming a greater importance since it is desired to reduce the media volume to the lowest level possible while still retaining good metals release.

  4. Characterization of bacterial communities in heavy metal contaminated soils.

    PubMed

    Roane, T M; Kellogg, S T

    1996-06-01

    Heavy metal pollution is a principle source of environmental contamination. We analyzed heavy metal impacted soil microbial communities and found that, in general, although lead adversely affected biomass, metabolic activity, and diversity, autochthonous lead- and cadmium-resistant isolates were found. In several metal-stressed soils, the microbial community consisted of two populations, either resistant or sensitive to lead. Additionally, a lead-resistant isolate was isolated from a control soil with no known previous exposure to lead, suggesting widespread lead resistance. Lead-resistant genera isolated included Pseudomonas, Bacillus, Corynebacterium, and Enterobacter species. Plasmids, ranging from 5 to 260 kb, were not detected through standard purifications from lead-resistant isolates. Positive correlations existed between antibiotic resistance and isolation habitat for lead-resistant strains, microbial metabolic activity and soil type, soluble lead concentration and microbial diversity, and arsenic concentration and total or viable cell concentrations. PMID:8801006

  5. Remediation of metal-contaminated urban soil using flotation technique.

    PubMed

    Dermont, G; Bergeron, M; Richer-Laflèche, M; Mercier, G

    2010-02-01

    A soil washing process using froth flotation technique was evaluated for the removal of arsenic, cadmium, copper, lead, and zinc from a highly contaminated urban soil (brownfield) after crushing of the particle-size fractions >250microm. The metal contaminants were in particulate forms and distributed in all the particle-size fractions. The particle-by-particle study with SEM-EDS showed that Zn was mainly present as sphalerite (ZnS), whereas Cu and Pb were mainly speciated as various oxide/carbonate compounds. The influence of surfactant collector type (non-ionic and anionic), collector dosage, pulp pH, a chemical activation step (sulfidization), particle size, and process time on metal removal efficiency and flotation selectivity was studied. Satisfactory results in metal recovery (42-52%), flotation selectivity (concentration factor>2.5), and volume reduction (>80%) were obtained with anionic collector (potassium amyl xanthate). The transportation mechanisms involved in the separation process (i.e., the true flotation and the mechanical entrainment) were evaluated by the pulp chemistry, the metal speciation, the metal distribution in the particle-size fractions, and the separation selectivity indices of Zn/Ca and Zn/Fe. The investigations showed that a great proportion of metal-containing particles were recovered in the froth layer by entrainment mechanism rather than by true flotation process. The non-selective entrainment mechanism of the fine particles (<20 microm) caused a flotation selectivity drop, especially with a long flotation time (>5 min) and when a high collector dose is used. The intermediate particle-size fraction (20-125 microm) showed the best flotation selectivity. PMID:19959208

  6. Response of a salt marsh microbial community to metal contamination

    NASA Astrophysics Data System (ADS)

    Mucha, Ana P.; Teixeira, Catarina; Reis, Izabela; Magalhães, Catarina; Bordalo, Adriano A.; Almeida, C. Marisa R.

    2013-09-01

    Salt marshes are important sinks for contaminants, namely metals that tend to accumulate around plant roots and could eventually be taken up in a process known as phytoremediation. On the other hand, microbial communities display important roles in the salt marsh ecosystems, such as recycling of nutrients and/or degradation of organic contaminants. Thus, plants can benefit from the microbial activity in the phytoremediation process. Nevertheless, above certain levels, metals are known to be toxic to microorganisms, fact that can eventually compromise their ecological functions. In this vein, the aim of present study was to investigate, in the laboratory, the effect of selected metals (Cd, Cu and Pb) on the microbial communities associated to the roots of two salt marsh plants. Sediments colonized by Juncus maritimus and Phragmites australis were collected in the River Lima estuary (NW Portugal), and spiked with each of the metals at three different Effects Range-Median (ERM) concentrations (1, 10×, 50×), being ERM the sediment quality guideline that indicates the concentration above which adverse biological effects may frequently occur. Spiked sediments were incubated with a nutritive saline solution, being left in the dark under constant agitation for 7 days. The results showed that, despite the initial sediments colonized by J. maritimus and P. australis displayed significant (p < 0.05) differences in terms of microbial community structure (evaluated by ARISA), they presented similar microbial abundances (estimated by DAPI). Also, in terms of microbial abundance, both sediments showed a similar response to metal addition, with a decrease in number of cells only observed for the higher addition of Cu. Nevertheless, both Cu and Pb, at intermediate metals levels promote a shift in the microbial community structure, with possibly effect on the ecological function of these microbial communities in salt marshes. These changes may affect plants phytoremediation

  7. Impact of extreme metal contamination at the supra-individual level in a contaminated bay ecosystem.

    PubMed

    Wu, Bin; Li, Xuegang; Song, Jinming; Hu, Limin; Shi, Xuefa

    2016-07-01

    Anthropogenic stressors impact the global environment and adversely affect the health of organisms and humans. This study was designed as an attempt to evaluate the ecological consequences of severe metal contamination at the supra-individual level based on a field investigation in Jinzhou Bay (JZB), North China in 2010. The chemical results showed high concentrations of metals in the sediment of JZB that were ~129 times greater than the local geochemical background. Furthermore, the measured metals exhibited considerably high toxicity potential indicated by sediment quality guidelines (SQGs). The mean SQGs quotients suggested the overall toxicity incidence was >70% in locations neighboring the Wulihe River mouth. Biomonitoring revealed 116 individuals distributed among a mere 6 species, 4 of which were polychaetes, at 33% of the sampling sites. Thus, few benthic organisms were present in the damaged community structures across the region, which was consistent with the extreme metal contamination. Moreover, the sediment quality assessment, in a weight of evidence framework, demonstrated that the sediment throughout the entire JZB was moderately to severely impaired, especially in the vicinity of the Wulihe River mouth. By synthesizing the present and previous chemical-biological monitoring campaigns, a possible cause-effect relationship between chemical stressors and benthic receptors was established. We also found that the hydrodynamics, sediment sources, and geochemical characteristics of the metals (in addition to the sources of the metals) were responsible for the geochemical distribution of metals in JZB. The significance of the overall finding is that the deleterious responses observed at the community level may possibly be linked to the extreme chemical stress in the sediment of JZB. PMID:26994798

  8. Sensitivity of six subantarctic marine invertebrates to common metal contaminants.

    PubMed

    Holan, Jessica R; King, Catherine K; Davis, Andrew R

    2016-09-01

    A long history of anthropogenic activities in the relatively pristine subantarctic has resulted in areas of accumulated waste and contaminants. Sensitivities to metals of subantarctic and Antarctic species may contrast with related species from temperate and tropical areas because of the unique characteristics of polar biota. In addition, response to contaminants may be delayed, and hence longer exposure periods may be required in toxicity tests with polar species. In the present study, the sensitivity of 6 common subantarctic marine invertebrates to copper, zinc, and cadmium contaminants was determined. Large variations in sensitivities, both between species and between metals within species, were found. The bivalve Gaimardia trapesina and the copepod Harpacticus sp. were the most sensitive to copper, with 7-d median lethal concentration (LC50) values for both species ranging between 28 μg/L and 62 μg/L, whereas the copepod Tigriopus angulatus was the most tolerant of copper (7-d Cu LC50 1560 μg/L). Sensitivity to zinc varied by approximately 1 order of magnitude between species (7-d LC50: 329-3057 μg/L). Sensitivity to cadmium also varied considerably between species, with 7-d LC50 values ranging from 1612 μg/L to >4383 μg/L. The present study is the first to report the sensitivity of subantarctic marine invertebrate to metals, and contributes significantly to the understanding of latitudinal gradients in the sensitivity of biota to metals. Although sensitivity is highly variable between species, in a global comparison of copepod data, it appears that species from higher latitudes may be more sensitive to copper. Environ Toxicol Chem 2016;35:2245-2251. © 2016 SETAC. PMID:26800986

  9. Biological attributes of rehabilitated soils contaminated with heavy metals.

    PubMed

    Valentim Dos Santos, Jessé; Varón-López, Maryeimy; Fonsêca Sousa Soares, Cláudio Roberto; Lopes Leal, Patrícia; Siqueira, José Oswaldo; de Souza Moreira, Fatima Maria

    2016-04-01

    This study aimed to evaluate the effects of two rehabilitation systems in sites contaminated by Zn, Cu, Pb, and Cd on biological soil attributes [microbial biomass carbon (Cmic), basal and induced respiration, enzymatic activities, microorganism plate count, and bacterial and fungal community diversity and structure by denaturing gradient gel electrophoresis (DGGE)]. These systems (S1 and S2) consisted of excavation (trenching) and replacement of contaminated soil by uncontaminated soil in rows with Eucalyptus camaldulensis planting (S1-R and S2-R), free of understory vegetation (S1-BR), or completely covered by Brachiaria decumbens (S2-BR) in between rows. A contaminated, non-rehabilitated (NR) site and two contamination-free sites [Cerrado (C) and pasture (P)] were used as controls. Cmic, densities of bacteria and actinobacteria, and enzymatic activities (β-glucosidase, acid phosphatase, and urease) were significantly higher in the rehabilitated sites of system 2 (S2-R and S2-BR). However, even under high heavy metal contents (S1-R), the rehabilitation with eucalyptus was also effective. DGGE analysis revealed similarity in the diversity and structure of bacteria and fungi communities between rehabilitated sites and C site (uncontaminated). Principal component analysis showed clustering of rehabilitated sites (S2-R and S2-BR) with contamination-free sites, and S1-R was intermediate between the most and least contaminated sites, demonstrating that the soil replacement and revegetation improved the biological condition of the soil. The attributes that most explained these clustering were bacterial density, acid phosphatase, β-glucosidase, fungal and actinobacterial densities, Cmic, and induced respiration. PMID:26662102

  10. Chelant soil-washing technology for metal-contaminated soil.

    PubMed

    Voglar, David; Lestan, Domen

    2014-01-01

    We demonstrate here, in a pilot-scale experiment, the feasibility of ethylenediaminetetraacetate (EDTA)based washing technology for soils contaminated with potentially toxic metals. Acid precipitation coupled to initial alkaline toxic metal removal and an electrochemical advanced oxidation process were used for average recovery of 76 +/- 2% of EDTA per batch and total recycle of water in a closed process loop. No waste water was generated; solid wastes were efficiently bitumen-stabilized before disposal. The technology embodiment, using conventional process equipment, such as a mixer for soil extraction, screen for soil/gravel separation, filter chamber presses for soil/liquid and recycled EDTA separation and soil rinsing, continuous centrifuge separator for removal of precipitated metals and electrolytic cells for process water cleansing, removed up to 72%, 25% and 66% of Pb, Zn and Cd from garden soil contaminated with up to 6960, 3797 and 32.6 mg kg(-1) of Pb, Zn and Cd, respectively, in nine 60kg soil batches. Concentrations of Pb and Zn remaining in the remediated soil and bioaccessible from the simulated human intestinal phase soil were reduced by 97% and 96% and were brought under the level of determination for Cd. In the most cost-effective operation mode, the material and energy costs of remediation amounted to 50.5 Euros ton(-1) soil and the total cost to 299 Euros ton(-1). PMID:24701937

  11. Noble metals: a toxicological appraisal of potential new environmental contaminants.

    PubMed Central

    Brubaker, P E; Moran, J P; Bridbord, K; Hueter, F G

    1975-01-01

    The public health benefits expected by reducing known hazardous emissions from mobile sources should not be compromised by increasing levels of other potentially hazardous unregulated emissions. Catalytic converters are going to be used to meet the statutory requirements on carbon monoxide and hydrocarbon emissions from light duty motor vehicles. Platinum and palladium metals are the catalytic materials to be used in these emission control devices. Preliminary experimental evidence and analysis of the impact of these control devices on the future use and demand for platinum indicates that this metal may appear at detectable levels in the environment by the end of this decade. At the present time, platinum and palladium are not present in the public environment and represent potentially new environmental contaminants as a consequence of use of this new abatement control technology. There is relatively little information available to adequately assess the potential health hazards that may be associated with exposure to these metals and their compounds. Analysis of the environmental problems and concerns associated with possible new environmental contaminants are discussed. Limited estimates are made on community exposure by use of a meteorological dispersion model. Biodegradation potential and attention is also given to the limited toxicological information available. PMID:50939

  12. [Immobilization impact of different fixatives on heavy metals contaminated soil].

    PubMed

    Wu, Lie-shan; Zeng, Dong-mei; Mo, Xiao-rong; Lu, Hong-hong; Su, Cui-cui; Kong, De-chao

    2015-01-01

    Four kinds of amendments including humus, ammonium sulfate, lime, superphosphate and their complex combination were added to rapid immobilize the heavy metals in contaminated soils. The best material was chosen according to the heavy metals' immobilization efficiency and the Capacity Values of the fixative in stabilizing soil heavy metals. The redistributions of heavy metals were determined by the European Communities Bureau of Referent(BCR) fraction distribution experiment before and after treatment. The results were as follows: (1) In the single material treatment, lime worked best with the dosage of 2% compared to the control group. In the compound amendment treatments, 2% humus combined with 2% lime worked best, and the immobilization efficiency of Pb, Cu, Cd, Zn reached 98.49%, 99.40%, 95.86%, 99.21%, respectively. (2) The order of Capacity Values was lime > humus + lime > ammonium sulfate + lime > superphosphate > ammonium sulfate + superphosphate > humus + superphosphate > humus > superphosphate. (3) BCR sequential extraction procedure results indicated that 2% humus combined with 2% lime treatment were very effective in immobilizing heavy metals, better than 2% lime treatment alone. Besides, Cd was activated firstly by 2% humus treatment then it could be easily changed into the organic fraction and residual fraction after the subsequent addition of 2% lime. PMID:25898680

  13. Functioning of metal contaminated garden soil after remediation.

    PubMed

    Jelusic, Masa; Grcman, Helena; Vodnik, Dominik; Suhadolc, Metka; Lestan, Domen

    2013-03-01

    The effect of remediation using three EDTA doses (10, 30, 60 mmol kg(-1)) on soil functioning was assessed using column experiment and Brassica rapa. Soil washing removed up to 77, 29 and 72% of metals from soil contaminated with 1378, 578 and 8.5 mg kg(-1) of Pb, Zn and Cd, respectively. Sequential extraction indicated removal from the carbonate soil fraction. Metal oral-accessibility from the stomach phase was reduced by up to 75 and from the small intestine by up to 79% (Pb). Part of metals (up to 0.8% Cd) was lost due to leaching from columns. Remediation reduced toxic metal soil-root transfer by up to 61% but did not prevent metal accumulation in leaves. The fitness of plants grown on EDTA washed soils (gas exchange, fluorescence) was not compromised. Remediation initially reduced the soil DNA content (up to 29%, 30 mmol kg(-1) EDTA) and changed the structure of microbial population. PMID:23246748

  14. Chelant extraction of heavy metals from contaminated soils.

    PubMed

    Peters, R W

    1999-04-23

    The current state of the art regarding the use of chelating agents to extract heavy metal contaminants has been addressed. Results are presented for treatability studies conducted as worst-case and representative soils from Aberdeen Proving Ground's J-Field for extraction of copper (Cu), lead (Pb), and zinc (Zn). The particle size distribution characteristics of the soils determined from hydrometer tests are approximately 60% sand, 30% silt, and 10% clay. Sequential extractions were performed on the 'as-received' soils (worst case and representative) to determine the speciation of the metal forms. The technique speciates the heavy metal distribution into an easily extractable (exchangeable) form, carbonates, reducible oxides, organically-bound, and residual forms. The results indicated that most of the metals are in forms that are amenable to soil washing (i.e. exchangeable+carbonate+reducible oxides). The metals Cu, Pb, Zn, and Cr have greater than 70% of their distribution in forms amenable to soil washing techniques, while Cd, Mn, and Fe are somewhat less amenable to soil washing using chelant extraction. However, the concentrations of Cd and Mn are low in the contaminated soil. From the batch chelant extraction studies, ethylenediaminetetraacetic acid (EDTA), citric acid, and nitrilotriacetic acid (NTA) were all effective in removing copper, lead, and zinc from the J-Field soils. Due to NTA being a Class II carcinogen, it is not recommended for use in remediating contaminated soils. EDTA and citric acid appear to offer the greatest potential as chelating agents to use in soil washing the Aberdeen Proving Ground soils. The other chelating agents studied (gluconate, oxalate, Citranox, ammonium acetate, and phosphoric acid, along with pH-adjusted water) were generally ineffective in mobilizing the heavy metals from the soils. The chelant solution removes the heavy metals (Cd, Cu, Pb, Zn, Fe, Cr, As, and Hg) simultaneously. Using a multiple-stage batch extraction

  15. Metal and metalloid contaminants in atmospheric aerosols from mining operations

    NASA Astrophysics Data System (ADS)

    Csavina, Janae

    Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb, Cd and other potentially toxic elements. Dust particles emitted from mining operations can accumulate in surrounding soils, natural waters and vegetation at relatively high concentrations through wind and water transport. Human exposure to the dust can occur through inhalation and, especially in the case of children, incidental dust ingestion, particularly during the early years when children are likely to exhibit pica. Furthermore, smelting operations release metals and metalloids in the form of fumes and ultra-fine particulate matter, which disperses more readily than coarser soil dusts. Of specific concern, these fine particulates can be transported to the lungs, allowing contaminants to be transferred into the blood stream. The main aim of this research is to assess the role of atmospheric aerosol and dust in the transport of metal and metalloid contaminants from mining operations to assess the deleterious impacts of these emissions to ecology and human health. In a field campaign, ambient particulates from five mining sites and four reference sites were examined utilizing micro-orifice deposit impactors (MOUDI), total suspended particulate (TSP) collectors, a scanning mobility particle sizer (SMPS), and Dusttrak optical particle counters for an understanding of the fate and transport of atmospheric aerosols. One of the major findings from size-resolved chemical characterization at three mining sites showed that the majority of the contaminant concentrations were found in the fine size fraction (<1 micrometer). Further, metal and metalloids (e.g. As, Cd, and Pb) around smelting activities are significantly enriched in both the coarse and fine size fraction when compared to reference sites. Additionally, with dust events being a growing concern because of predicted climate change and

  16. Metal resistant plants and phytoremediation of environmental contamination

    DOEpatents

    Meagher, Richard B.; Li, Yujing; Dhankher, Om P.

    2010-04-20

    The present disclosure provides a method of producing transgenic plants which are resistant to at least one metal ion by transforming the plant with a recombinant DNA comprising a nucleic acid encoding a bacterial arsenic reductase under the control of a plant expressible promoter, and a nucleic acid encoding a nucleotide sequence encoding a phytochelatin biosynthetic enzyme under the control of a plant expressible promoter. The invention also relates a method of phytoremediation of a contaminated site by growing in the site a transgenic plant expressing a nucleic acid encoding a bacterial arsenate reductase and a nucleic acid encoding a phytochelatin biosynthetic enzyme.

  17. SHEAR BOND STRENGTH OF METALLIC BRACKETS: INFLUENCE OF SALIVA CONTAMINATION

    PubMed Central

    Retamoso, Luciana Borges; Collares, Fabrício Mezzomo; Ferreira, Eduardo Silveira; Samuel, Susana Maria Werner

    2009-01-01

    Objective: To evaluate the influence of saliva contamination on shear bond strength and the bond failure pattern of 3 adhesive systems (Transbond XT, AdheSE and Xeno III) on orthodontic metallic brackets bonded to human enamel. Material and Methods: Seventy-two permanent human molars were cut longitudinally in a mesiodistal direction, producing seventy-two specimens randomly divided into six groups. Each system was tested under 2 different enamel conditions: no contamination and contaminated with saliva. In T, A and X groups, the adhesive systems were applied to the enamel surface in accordance with manufacturer's instructions. In TS, AS and XS groups, saliva was applied to enamel surface followed by adhesive system application. The samples were stored in distilled water at 37°C for 24 h, and then tested for shear bond strength in a universal testing machine (Emic, DL 2000) running at a crosshead speed of 1 mm/min. After bond failure, the enamel surfaces were observed under an optical microscope at 40x magnification. Results: The control and contaminated groups showed no significant difference in shear bond strength for the same adhesive system. However, shear bond strength of T group (17.03±4.91) was significantly higher than that of AS (8.58±1.73) and XS (10.39±4.06) groups (p<0.05). Regarding the bond failure pattern, TS group had significantly higher scores of no adhesive remaining on the tooth in the bonding area than other groups considering the adhesive remnant index (ARI) used to evaluate the amount of adhesive left on the enamel. Conclusion: Saliva contamination showed little influence on the 24-h shear bond strength of orthodontic brackets. PMID:19466249

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  19. Heavy metal release from metal-sulfide contaminated lake sediments exposed to artificial aeration

    SciTech Connect

    Schaumloffel, J.C.; Filby, R.H.; Moore, B.C.

    1995-12-01

    Hypolimnetic aeration (a form of artificial aeration) has gained popularity in recent years as a lake restoration and management tool. The addition of oxygen to eutrophic lakes by hypolimnetic aeration has been shown to increase overall water quality, without disturbing thermal stratification. The effects of increasing dissolved oxygen levels by aeration on the chemistry of heavy metals in lakes where the sediments are contaminated and the possible repercussions, however, have yet to be investigated. In this laboratory study, sediments collected from a lake contaminated with metal-sulfides were exposed to various levels of dissolved oxygen in the overyling water column. concentrations of zinc, cadmium, and lead in the water column were shown to increase concomitantly with increasing concentrations of sulfate in the water as aeration progressed. The effects of varying concentrations of dissolved oxygen, as well as other factors effecting the availability of previously insoluble heavy metals will be discussed.

  20. Risk of antibiotic resistance from metal contaminated soils

    NASA Astrophysics Data System (ADS)

    Knapp, Charles

    2013-04-01

    It is known that contaminated soils can lead to increased incidence of illness and disease, but it may also prevent our ability to fight disease. Many antibiotic resistant genes (ARG) acquired by bacteria originate from the environment. It is important to understand factors that influence levels of ARG in the environment, which could affect us clinically and agriculturally. The presence of elevated metal content in soils often promotes antibiotic resistance in exposed microorganisms. Using qPCR, the abundances of ARG to compare levels with geochemical conditions in randomly selected soils from several countries. Many ARG positively correlated with soil metal content, especially copper, chromium, nickel, lead, and iron. Results suggest that geochemical metal conditions influence the potential for antibiotic resistance in soil, which might be used to estimate baseline gene presence on various landscape scales and may translate to epidemiological risk of antibiotic-resistance transmission from the environment. This suggests that we may have to reconsider tolerances of metal pollution in the environment.

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

    NASA Astrophysics Data System (ADS)

    Lynch, Sarah; Batty, Lesley; Byrne, Patrick

    2016-04-01

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

  2. Melting of uranium-contaminated metal cylinders by electroslag refining

    SciTech Connect

    Uda, T.; Ozawa, Y.; Iba, H.

    1987-12-01

    Melt refining as a means of uranium decontamination of metallic wastes by electroslag refining was examined. Electroslag refining was selected because it is easy to scale up to the necessary industrial levels. Various thicknesses of iron and aluminum cylinders with uranium concentrations close to actual metallic wastes were melted by adding effective fluxes for decontamination. Thin-walled iron and aluminum cylinders with a fill ratio (electrode/mold cross-section ratio) of 0.05 could be melted, and the energy efficiency obtained was 16 to 25%. The ingot uranium concentration of the iron obtained was 0.01 to 0.015 ppm, which was close to the contamination level of the as-received specimen, while for aluminum it was 3 to 5 ppm, which was a few times higher than the as-received specimen contamination level of --0.9 ppm. To melt a thin aluminum cylinder in a steady state, with this fill ratio of 0.05, instantaneous electrode driving response control was desired. Electroslag refining gave better decontamination and energy economization results than by a resistance furnace.

  3. Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations.

    PubMed

    Csavina, Janae; Landázuri, Andrea; Wonaschütz, Anna; Rine, Kyle; Rheinheimer, Paul; Barbaris, Brian; Conant, William; Sáez, A Eduardo; Betterton, Eric A

    2011-10-01

    Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. Fine particulates such as those resulting from smelting operations may disperse more readily into the environment than coarser tailings dust. Fine particles also penetrate more deeply into the human respiratory system, and may become more bioavailable due to their high specific surface area. In this work, we report the size-fractionated chemical characterization of atmospheric aerosols sampled over a period of a year near an active mining and smelting site in Arizona. Aerosols were characterized with a 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactor (MOUDI), a scanning mobility particle sizer (SMPS), and a total suspended particulate (TSP) collector. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources. Observation of ultrafine particle number concentration (SMPS) show the highest readings when the wind comes from the general direction of the smelting operations site. PMID:23441050

  4. Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations

    PubMed Central

    Csavina, Janae; Landázuri, Andrea; Wonaschütz, Anna; Rine, Kyle; Rheinheimer, Paul; Barbaris, Brian; Conant, William; Sáez, A. Eduardo; Betterton, Eric A.

    2013-01-01

    Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. Fine particulates such as those resulting from smelting operations may disperse more readily into the environment than coarser tailings dust. Fine particles also penetrate more deeply into the human respiratory system, and may become more bioavailable due to their high specific surface area. In this work, we report the size-fractionated chemical characterization of atmospheric aerosols sampled over a period of a year near an active mining and smelting site in Arizona. Aerosols were characterized with a 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactor (MOUDI), a scanning mobility particle sizer (SMPS), and a total suspended particulate (TSP) collector. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources. Observation of ultrafine particle number concentration (SMPS) show the highest readings when the wind comes from the general direction of the smelting operations site. PMID:23441050

  5. Spatial Patterns of Heavy Metal Contamination by Urbanization.

    PubMed

    Delbecque, Nele; Verdoodt, Ann

    2016-01-01

    Spatial analysis of heavy metals (HMs) is an important step toward developing predictive models of urban HM contamination. This study assessed the spatial distribution of the enrichment of eight HMs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the city of Ghent, Belgium. A database with soil HM concentrations measured at 2194 point observations was collected from the Public Waste Agency of Flanders. The degree of anthropogenic HM enrichment was quantified using an urban pollution index (PI). Enrichment of HMs showed high variations throughout the study area. Observed concentrations of As, Cd, Cr, and Hg did not exceed expected background values for the majority of the sampling locations (PI ≤ 1 for 76% [As], 64% [Cd], 50% [Cr], and 74% [Hg] of sampling points). Accordingly, predicted PI values of these HMs in Ghent were on average <2. On the other hand, observed median PIs for Cu, Ni, Pb, and Zn surpassed expected background values (PI >1) in 66, 76, 68, and 66% of the cases. The predicted PI means for the entire study area were 3.46 (Cu), 2.06 (Ni), 3.26 (Pb), and 3.28 (Zn). Comparison between various land use types and times since development indicated that HM enrichment was generally highest in urban land uses built up before 1933. Results, however, suggested that spatial patterns of HM contamination are difficult to predict in cities with a long history of industrialization without knowledge on the spatial distribution of (potentially) contaminating historical industrial activities. PMID:26828155

  6. Heavy metal contamination of vegetables in Isfahan, Iran

    PubMed Central

    Jafarian-Dehkordi, A.; Alehashem, M.

    2013-01-01

    Vegetables are an inevitable and important part of a healthy and balanced diet. They could be contaminated by heavy metals in many ways including irrigation by sewage water and industrial effluents sewage sludge, vehicular emissions, industrial waste and atmospheric deposition. In this study, we sought to determine if some vegetables (cucumbers, tomatoes, cabbage, lettuce, potatoes, onions, carrots, persian leeks, dill, spinach, coriander, parsley) grown locally in the suburban of Isfahan city and sold in the urban markets are contaminated with cadmium (Cd), chromium (Cr) and lead (Pb). Vegetables were sampled from August to October 2010. After washing, they were oven-dried and digested using three-acid mixture (70% HNO3, 65% HClO4 and 70% H2SO4). Analyzes of the heavy metals was performed using atomic absorption spectrophotometry. To validate the assay method, intra-day and inter-day variation studies were performed. The concentrations (μg/g) of heavy metals in the samples ranged from 0.00 to 3.66 for Cd, 0.00 to 6.00 for Cr and 0.00 to 7.14 for Pb. The highest concentration of heavy metals was for Pb. The results showed that the amount of Cd, Cr and Pb of some samples exceeded the recommended levels. The amount of Cd in cucumber, tomatoes, potatoes with skin, carrots, and spinach was significantly higher in the samples collected from Isfahanak, Dashti and Ilchi farms than those of Dorche farms. Also, the amount of Cr in onion, carrots, and spinach was significantly higher in samples collected from Isfahanak, Dashti and Ilchi farms than those of Dorche farms. However, the amount of Pb in the carrots and leek was significantly higher in the samples collected from Dorche farms than those of Isfahanak, Dashti and Ilchi farms. It can be concluded from the findings of this study that the amounts of Cd, Cr, and Pb were higher than the acceptable levels recommended by WHO/FAO. Also, higher amount of Cd and Cr in some samples collected from Isfahanak, Dashti and Ilchi

  7. Metal contamination in wildlife living near two zinc smelters

    USGS Publications Warehouse

    Beyer, W.N.; Pattee, O.H.; Sileo, L.; Hoffman, D.J.; Mulhern, B.M.

    1985-01-01

    Wildlife in an oak forest on Blue Mountain was studied 10 km upwind (Bake Oven Knob site) and 2 km downwind (Palmerton site) of two zinc smelters in eastern Pennsylvania, USA. Previous studies at sites near these smelters had shown changes in populations of soil microflora, lichens, green plants and litter-inhabiting arthropods. The 02 soil litter horizon at Palmerton was heavily contaminated with Pb (2700 mg kg-1), Zn (24000 mg kg-1), and Cd (710 mg kg-1), and to a lesser extent with Cu (440 mg kg-1). Various kinds of invertebrates (earthworms, slugs and millipedes) that feed on soil litter or soil organic matter were rare at, or absent from, the Palmerton site. Those collected at Bake Oven Knob tended to have much higher concentrations of metals than did other invertebrates. Frogs, toads and salamanders were very rare at, or absent from, the Palmerton site, but were present at Bake Oven Knob and at other sites on Blue Mountain farther from the smelters. Metal concentrations (dry wt) in different organisms from Palmerton were compared. Concentrations of Pb were highest in shrews (110 mg kg-1), followed by songbirds (56 mg kg-1), leaves (21 mg kg-1), mice (17 mg kg-1), carrion insects (14 mg kg-1), berries (4.0 mg kg-1), moths (4,3 mg kg-1) and fungi (3.7 mg kg-1). Concentrations of Cd, in contrast, were highest in carrion insects (25 mg kg-1 ),followed by fungi (9.8 mg kg-1), leaves (8.1 mg kg-1), shrews (7.3 mg kg-I), moths (4.9 mg kg-1), mice (2.6 mg kg -1), songbirds (2.5 mg kg -1) and berries (1.2 mg kg-1). Concentrations of Zn and Cu tended to be highest in the same organisms that had the highest concentrations of Cd. Only a small proportion of the metals in the soil became incorporated into plant foliage, and much of the metal contamination detected in the biota probably came from aerial deposition. The mice from both sites seemed to be healthy. Shrews had higher concentrations of metals than did mice, and one shrew showed evidence of Pb poisoning; its red

  8. Heavy Metal Contamination in the Taimyr Peninsula, Siberian Arctic

    SciTech Connect

    Allen-Gil, Susan M.; Ford, Jesse; Lasorsa, Brenda K.; Monetti, Matthew; Vlasova, Tamara; Landers, Dixon H.

    2003-01-01

    The Taimyr Peninsula is directly north of the world's largest heavy metal smelting complex (Norilsk, Russia). Despite this proximity, there has been little research to examine the extent of contamination of the Taimyr Peninsula. We analyzed heavy metal concentrations in lichen (Cetraria cucullata), moss (Hylocomium splendens), soils, lake sediment, freshwater fish (Salvelinus alpinus, Lota lota, and Coregonus spp.) and collared lemming (Dicrostonyx torquatus) from 13 sites between 30 and 300 km from Norilsk. Element concentrations were low in both C. cucullata and H. splendens, although concentrations of Al, Fe, Cu, Ni, and Pb were significantly higher than those in Arctic Alaska, probably due to natural differences in the geochemical environments. Inorganic surface soils had significantly higher concentrations of Cd, Zn, Pb, and Mg than inorganic soils at depth, although a lake sediment core from the eastern Taimyr Peninsula indicated no recent enrichment by atmospherically transported elements. Tissue concentrations of heavy metals in fish and lemming were not elevated relative to other Arctic sites. Our results show that the impact of the Norilsk smelting complex is primarily localized rather than regional, and does not extend northward beyond 100 km.

  9. Microbial links between sulfate reduction and metal retention in uranium- and heavy metal-contaminated soil.

    PubMed

    Sitte, Jana; Akob, Denise M; Kaufmann, Christian; Finster, Kai; Banerjee, Dipanjan; Burkhardt, Eva-Maria; Kostka, Joel E; Scheinost, Andreas C; Büchel, Georg; Küsel, Kirsten

    2010-05-01

    Sulfate-reducing bacteria (SRB) can affect metal mobility either directly by reductive transformation of metal ions, e.g., uranium, into their insoluble forms or indirectly by formation of metal sulfides. This study evaluated in situ and biostimulated activity of SRB in groundwater-influenced soils from a creek bank contaminated with heavy metals and radionuclides within the former uranium mining district of Ronneburg, Germany. In situ activity of SRB, measured by the (35)SO(4)(2-) radiotracer method, was restricted to reduced soil horizons with rates of < or =142 +/- 20 nmol cm(-3) day(-1). Concentrations of heavy metals were enriched in the solid phase of the reduced horizons, whereas pore water concentrations were low. X-ray absorption near-edge structure (XANES) measurements demonstrated that approximately 80% of uranium was present as reduced uranium but appeared to occur as a sorbed complex. Soil-based dsrAB clone libraries were dominated by sequences affiliated with members of the Desulfobacterales but also the Desulfovibrionales, Syntrophobacteraceae, and Clostridiales. [(13)C]acetate- and [(13)C]lactate-biostimulated soil microcosms were dominated by sulfate and Fe(III) reduction. These processes were associated with enrichment of SRB and Geobacteraceae; enriched SRB were closely related to organisms detected in soils by using the dsrAB marker. Concentrations of soluble nickel, cobalt, and occasionally zinc declined < or =100% during anoxic soil incubations. In contrast to results in other studies, soluble uranium increased in carbon-amended treatments, reaching < or =1,407 nM in solution. Our results suggest that (i) ongoing sulfate reduction in contaminated soil resulted in in situ metal attenuation and (ii) the fate of uranium mobility is not predictable and may lead to downstream contamination of adjacent ecosystems. PMID:20363796

  10. Microbial Links between Sulfate Reduction and Metal Retention in Uranium- and Heavy Metal-Contaminated Soil▿

    PubMed Central

    Sitte, Jana; Akob, Denise M.; Kaufmann, Christian; Finster, Kai; Banerjee, Dipanjan; Burkhardt, Eva-Maria; Kostka, Joel E.; Scheinost, Andreas C.; Büchel, Georg; Küsel, Kirsten

    2010-01-01

    Sulfate-reducing bacteria (SRB) can affect metal mobility either directly by reductive transformation of metal ions, e.g., uranium, into their insoluble forms or indirectly by formation of metal sulfides. This study evaluated in situ and biostimulated activity of SRB in groundwater-influenced soils from a creek bank contaminated with heavy metals and radionuclides within the former uranium mining district of Ronneburg, Germany. In situ activity of SRB, measured by the 35SO42− radiotracer method, was restricted to reduced soil horizons with rates of ≤142 ± 20 nmol cm−3 day−1. Concentrations of heavy metals were enriched in the solid phase of the reduced horizons, whereas pore water concentrations were low. X-ray absorption near-edge structure (XANES) measurements demonstrated that ∼80% of uranium was present as reduced uranium but appeared to occur as a sorbed complex. Soil-based dsrAB clone libraries were dominated by sequences affiliated with members of the Desulfobacterales but also the Desulfovibrionales, Syntrophobacteraceae, and Clostridiales. [13C]acetate- and [13C]lactate-biostimulated soil microcosms were dominated by sulfate and Fe(III) reduction. These processes were associated with enrichment of SRB and Geobacteraceae; enriched SRB were closely related to organisms detected in soils by using the dsrAB marker. Concentrations of soluble nickel, cobalt, and occasionally zinc declined ≤100% during anoxic soil incubations. In contrast to results in other studies, soluble uranium increased in carbon-amended treatments, reaching ≤1,407 nM in solution. Our results suggest that (i) ongoing sulfate reduction in contaminated soil resulted in in situ metal attenuation and (ii) the fate of uranium mobility is not predictable and may lead to downstream contamination of adjacent ecosystems. PMID:20363796

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  12. Metal contamination of vineyard soils in wet subtropics (southern Brazil).

    PubMed

    Mirlean, Nicolai; Roisenberg, Ari; Chies, Jaqueline O

    2007-09-01

    The vine-growing areas in Brazil are the dampest in the world. Copper maximum value registered in this study was as much as 3200 mg kg(-1), which is several times higher than reported for vineyard soils in temperate climates. Other pesticide-derived metals accumulate in the topsoil layer, surpassing in the old vineyards the background value several times for Zn, Pb, Cr and Cd. Copper is transported to deeper soils' horizons and can potentially contaminate groundwater. The soils from basaltic volcanic rocks reveal the highest values of Cu extracted with CaCl(2), demonstrating a high capacity of copper transference into plants. When evaluating the risks of copper's toxic effects in subtropics, the soils from rhyolitic volcanic rocks are more worrisome, as the Cu extracted with ammonium acetate 1M surpasses the toxic threshold as much as 4-6 times. PMID:17321651

  13. E-SMART system for in-situ detection of environmental contaminants. Quarterly progress report

    SciTech Connect

    1996-01-01

    Environmental Systems Management, Analysis and Reporting neTwork (E-SMART) is a comprehensive, fully-integrated approach to in-situ, real-time detection and monitoring of environmental contaminants. E-SMART will provide new class of smart, highly sensitive, chemically-specific, in-situ, multichannel microsensors utilizing integrated optical interferometry technology, large, commercially viable set of E-SMART-compatible sensors, samplers, and network management components, and user-friendly graphical user interface for data evaluation and visualization.

  14. Spatial patterns of heavy metal contamination by urbanization

    NASA Astrophysics Data System (ADS)

    Delbecque, Nele; Verdoodt, Ann

    2015-04-01

    Source identification is an important step towards predictive models of urban heavy metal (HM) contamination. This study assesses the spatial distribution of enrichment of eight HMs (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in the city of Ghent (156.18 km2; Belgium). A database with HM concentrations measured in the topsoil at 2138 point observations was collected from the Public Waste Agency of Flanders. The degree of anthropogenic HM enrichment was quantified using an urban pollution index (PI). Enrichment of HMs showed high variations throughout the study area due to manifold anthropogenic sources. Topsoil in Ghent was especially enriched with Cu, Ni, Pb and Zn, with median PI's of 1.91, 1.74, 2.12 and 2.02 respectively. Contrastingly, As, Cd, Hg, Cr generally did not exceed expected background concentrations, with median PI values < 1. Stratification of the PI based on land use (agriculture, park and recreation, residential zones, harbor and industry) generally revealed high enrichment of Cu, Ni, Pb and Zn in residential areas linked to housing and traffic, but proved unsatisfactory to capture major trends in urban spatial HM distributions. Moreover, an important control of industrial and traffic emissions is suggested for Ni, Cu, Pb and Zn. Industrial non-airborne point source contaminations were mainly historical, rather than linked to current industrial activities. Results indicated that urban-rural gradients or current land use stratification approaches are inadequate to predict spatial HM distributions in cities with a long history of industrialization.

  15. Humic substances-enhanced electroremediation of heavy metals contaminated soil.

    PubMed

    Bahemmat, Mahdi; Farahbakhsh, Mohsen; Kianirad, Mehran

    2016-07-15

    The effects of catholyte conditioning and the use of humic acids (HAs) and fulvic acids (FAs) as chelating agents to improve electrokinetic (EK) remediation efficiency were investigated using a real and highly contaminated soil. By applying a constant voltage (2.0V/cm) to the soil, pH and current changes and heavy metals (HMs) concentration were investigated through a range of durations and positions. The observations demonstrated that both catholyte conditioning with 0.1N HNO3 and using humic substances (HSs) enhance remediation efficiency. After 20 days of EK treatment, the removal efficiency of HMs in HS-enhanced EK remediation was about 2.0-3.0 times greater than when unenhanced. The quantity of HMs moving toward the cathode exceeded the anode, from which it could be reasonably inferred that most negatively charged HM-HS complexes were moved by electroosmotic forces. Further, free HM cations and positively charged complexed HMs migrated to the catholyte compartment by electromigration. The results obtained in this study, demonstrate the suitability of HS-enhanced EK remediation in HMs contaminated soil. PMID:27058638

  16. Eco-monitoring of highly contaminated areas: historic heavy metal contamination in tree ring records

    NASA Astrophysics Data System (ADS)

    Baross, Norbert; Jordán, Győző; Albert, Julianna; Abdaal, Ahmed; Anton, Attila

    2014-05-01

    This study examines and compares tree rings of trees grown in a mining area highly contaminated with heavy metals. Tree rings offers an excellent opportunity for eco-monitoring polluted areas. Contamination dispersion from the source to the receptors can be studied in time and space. The sampled area is located in the eastern part of the Matra Mts. of the Inner-Carpathian calc-alkaline Volcanic Arc (Hungary) with abundant historical ore (Pb, Zn, Cu, etc.) mining in the area. Dense forests are composed of the most typical association of the Turkey oak (Quercus cerris). Scots pine (Pinus sylvestris), European black pine (Pinus nigra), oak (Quercus robur), beech (Fagus sylvatica), and hornbeam (Carpinus betulus) also occurs in the landscape. Sampled trees are located within a 1km radius of the abandoned historic ore mines. Sample sites were located above the old mines and waste rock heaps, under the waste rock heaps and on the floodplain of the Ilona Creek. The sampled trees were selected by the following criteria: the tree should be healthy, showing no signs of thunderbolt or diseases and having a minimum diameter of 50 cm. Samples were taken with a tree borer at the height of 150 cm. At the same time, soil samples were also taken near the trees in a 25 cm depth. Prior to laboratory analysis, the samples measured and air dried. Every fifth years tree ring was taken from the samples under microscope, working backwards from the most recent outer ring (2012, the year of the sampling). Samples were digested with a mixture of H2SO4 and H2O2m in Teflon vessels in a microwave unit. The samples were analyzed by ICP-OES instrument. The results were evaluated with statistical method. Results revealed a consistent picture showing distinct locations and years of the contamination history in the former mining area. Some elements are built into the trees more efficiently than other elements depending on mobility in the soil solution that is influenced by soil chemical properties

  17. Metal boride catalysts for indirect liquefaction. Quarterly technical progress report, December 1, 1983-February 29, 1984

    SciTech Connect

    Bartholomew, C.H.

    1984-04-12

    During the sixth quarter four boron-promoted cobalt catalysts were prepared by a new boriding process using diborane gas as the boriding agent. These catalysts were characterized by chemical analysis, BET, H/sub 2/ chemisorption, and x-ray diffraction. Temperature-programmed desorption spectra of H/sub 2/ were obtained for a sodium-promoted cobalt boride and a sodium-promoted Co/SiO/sub 2/. Four cobalt catalysts (unsupported, boron-promoted, sodium-promoted, and doubly-promoted) were tested for CO hydrogenation activity and selectivity at 1 atm and 3 to 4 temperatures in the range of 190 to 240/sup 0/C. About 10% of the surface of cobalt boride consists of reduced metallic cobalt. The addition of sodium to cobalt increases its binding energy with H/sub 2/ and its activation energy for H/sub 2/ adsorption. Boron does not affect the activity of cobalt; sodium decreases it by a factor of 10. Cobalt boride produces lighter hydrocarbon products relative to cobalt; sodium-promoted cobalt produces heavier products, more alcohols, and more CO/sub 2/. 29 references, 10 figures, 4 tables.

  18. Contamination, toxicity and speciation of heavy metals in an industrialized urban river: Implications for the dispersal of heavy metals.

    PubMed

    Wu, Qihang; Zhou, Haichao; Tam, Nora F Y; Tian, Yu; Tan, Yang; Zhou, Song; Li, Qing; Chen, Yongheng; Leung, Jonathan Y S

    2016-03-15

    Urban rivers are often utilized by the local residents as water source, but they can be polluted by heavy metals due to industrialization. Here, the concentrations, toxicity, speciation and vertical profiles of heavy metals in sediment were examined to evaluate their impact, dispersal and temporal variation in Dongbao River. Results showed that the sediment in the industrialized areas was seriously contaminated with Cr, Cu and Ni which posed acute toxicity. Heavy metals, except Cr and Pb, were mainly associated with non-residual fractions, indicating their high mobility and bioavailability. The non-industrialized areas were also seriously contaminated, suggesting the dispersal of heavy metals along the river. The surface sediment could be more contaminated than the deep sediment, indicating the recent pollution events. Overall, when the point sources are not properly regulated, intense industrialization can cause both serious contamination and dispersal of heavy metals, which have far-reaching consequences in public health and environment. PMID:26856647

  19. Remediation of Heavy Metal(loid)s Contaminated Soils – To Mobilize or To Immobilize?

    EPA Science Inventory

    Unlike organic contaminants, metal(loid)s do not undergo microbial or chemical degradation and persist for a long time after their introduction. Bioavailability of metal(loid)s plays a vital role in the remediation of contaminated soils. In this review, the remediation of heavy ...

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

    PubMed Central

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

    2016-01-01

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

  1. Changes in metal contamination levels in estuarine sediments around India--an assessment.

    PubMed

    Chakraborty, Parthasarathi; Ramteke, Darwin; Chakraborty, Sucharita; Nagender Nath, B

    2014-01-15

    This review is the first attempt to comprehend the changes in metal contamination levels in surface estuarine sediments with changing time around India. Contamination factor, geoaccumulation index, pollution load index, effects range low and effects range median analysis were used to evaluate the quality of the estuarine sediments (by using the available literature data). This study suggests that estuarine sediments from the east coast of India were comparatively less contaminated by metals than the west coast. Sediments from those estuaries were found to be more contaminated by metals on which major cities are located. An improvement in estuarine sediment quality (in terms of metal contamination) over time around India was noticed. This study provides managers and decision-makers of environmental protection agency with a better scientific understanding for decision-making in controlling metal pollution in estuarine sediments around India. PMID:24211100

  2. Composition and process for organic and metal contaminant fixation in soil

    SciTech Connect

    Schwitzgebel, K.

    1994-02-08

    A method and compositions using a first ferrous iron containing solution with the iron concentration in excess of theoretical requirements are presented to treat a contaminated site. Hexavalent chromium is reduced to trivalent chromium and trivalent chromium is coprecipitated with other heavy metals. A second solution of silicate containing a destabilizing salt is used to form a relatively impermeable gel in the contaminated site thereby fixing metals and organics to the extent that there should be no detectable ground water contamination.

  3. Composition and process for organic and metal contaminant fixation in soil

    DOEpatents

    Schwitzgebel, Klaus

    1994-02-08

    A method and compositions using a first ferrous iron containing solution with the iron concentration in excess of theoretical requirements to treat a contaminated site to reduce hexavalent chromium to trivalent chromium and coprecipitate trivalent chromium with other heavy metals and using a second solution of silicate containing a destabilizing salt to form a relatively impermeable gel in the contaminated site thereby fixing metals and organics to the extent that there should be no detectable ground water contamination.

  4. Pollution status of Pakistan: a retrospective review on heavy metal contamination of water, soil, and vegetables.

    PubMed

    Waseem, Amir; Arshad, Jahanzaib; Iqbal, Farhat; Sajjad, Ashif; Mehmood, Zahid; Murtaza, Ghulam

    2014-01-01

    Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health. PMID:25276818

  5. Pollution Status of Pakistan: A Retrospective Review on Heavy Metal Contamination of Water, Soil, and Vegetables

    PubMed Central

    Arshad, Jahanzaib; Iqbal, Farhat; Sajjad, Ashif; Mehmood, Zahid

    2014-01-01

    Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health. PMID:25276818

  6. Heavy metal contamination in a vulnerable mangrove swamp in South China.

    PubMed

    Wang, Yutao; Qiu, Qiu; Xin, Guorong; Yang, Zhongyi; Zheng, Jing; Ye, Zhihong; Li, Shaoshan

    2013-07-01

    Concentrations of six heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavy metals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavy metals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavy metals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavy metals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavy metals after its propagule stage for its regeneration and growth to be significantly affected by heavy metal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavy metals in an ecosystem. PMID:23203819

  7. Heavy metal contamination of river Yamuna, Haryana, India: Assessment by Metal Enrichment Factor of the Sediments.

    PubMed

    Kaushik, A; Kansal, Ankur; Santosh; Meena; Kumari, Shiv; Kaushik, C P

    2009-05-15

    Concentration of Heavy Metals (Cd, Cr, Fe, Ni) in water, plants and sediments of river Yamuna flowing in Haryana through Delhi are reported here selecting 14 stations covering the upstream and downstream sites of major industrial complexes of the State. Some important characteristics of river water and sediments (pH, EC, Cl(-), SO(3)(2-), and PO(4)(3-) in water and sediments, COD of water and organic matter content of sediments) were also analysed and inter-relationships of all these parameters with heavy metal concentration in different compartments were examined. The sediments of the river show significant enrichment with Cd and Ni indicating inputs from industrial sources. Concentrations of Cr are moderate and show high enrichment values only at a few sites. Enrichment factor for Fe is found to be <1, showing insignificant effect of anthropogenic flux. Concentrations of these metals in river water are generally high exceeding the standard maximum permissible limits prescribed for drinking water, particularly in the downstream sites. The aquatic plants show maximum accumulation of Fe. The other heavy metals Cd, Cr and Ni, though less in concentration, show some accumulation in the plants growing in contaminated sites. Interrelationships of metal concentration with important characteristics of water and sediment have been analysed. Analysis of heavy metals in water, sediments and littoral flora in the stretch of river Yamuna is first study of itself and interrelationship of metal concentration and other important characteristics make the study significant and interesting in analysing the pollution load at different points of the river body. PMID:18809251

  8. Contaminated Metal Components in Dismantling by Hot Cutting Processes

    SciTech Connect

    Cesari, Franco G.; Conforti, Gianmario; Rogante, Massimo; Giostri, Angelo

    2006-07-01

    During the preparatory dismantling activities of Caorso's Nuclear Power Plant (NPP), an experimental campaign using plasma and oxyacetylene metal cutting processes has been performed and applied to plates and tubes exposed to the coolant steam of the reactor. The plant (Boiling Water Reactor, 870 MWe) was designed and built in the 70's, and it was fully operating by 1981 to 1986 being shut down after 1987 Italy's poll that abrogated nuclear power based on U235 fission. The campaign concerns no activated materials, even if the analyses have been performed of by use contaminated components under the free release level, not yet taking into account radioactivity. In this paper, the parameters related to inhalable aerosol, solid and volatile residuals production have been, studied during hot processes which applies the same characteristics of the cutting in field for the dismantling programs of Caorso NPP. The technical parameters such as cutting time and cutting rate vs. pipe diameter/thickness/schedule or plate thickness for ferritic alloys and the emissions composition coming from the sectioning are also reported. The results underline the sort of trouble that can emerge in the cutting processes, in particular focusing on the effects comparison between the two cutting processes and the chemical composition of powders captured by filtering the gaseous emission. Some preliminary considerations on methodology to be used during the dismantling have been presented. (authors)

  9. Propolis as an indicator of environmental contamination by metals.

    PubMed

    Finger, Daiane; Filho, Irineo Kelte; Torres, Yohandra Reyes; Quináia, Sueli Pércio

    2014-03-01

    Concentrations of eleven representative metals (Al, Ca, Cd, Cr, Cu, K, Mg, Mn, Na, Pb and Zn) in forty-two propolis samples were measured by electrothermal atomization and flame atomic absorption spectrometry after calcination in a muffle furnace. Samples were collected from different regions from Paraná State - Brazil where apiculture is an important economic activity. Results showed that the average content of Al, Ca, K, Mg, Mn, Na and Zn in propolis was 0.68, 1.66, 7.59, 1.27, 0.08, 0.58 and 0.02 mg g(-1), respectively. Levels of Al, Ca, and Mg were statistically different in some regions of Paraná and could be used to assign the geographical origin of the propolis. The average concentration of the Cd, Cr, and Pb in raw propolis was 0.13, 5.53 and 9.85 μg g(-1), respectively, and allowed for identification of specific areas with environmental contamination. PMID:24414164

  10. Characterisation by PIXE RBS of metallic contamination of tissues surrounding a metallic prosthesis on a knee

    NASA Astrophysics Data System (ADS)

    Guibert, G.; Irigaray, J. L.; Moretto, Ph.; Sauvage, T.; Kemeny, J. L.; Cazenave, A.; Jallot, E.

    2006-09-01

    Implants used as biomaterials have to fulfill conditions of functionality, compatibility and sometimes bioactivity. There are four main families of biomaterials: metals and metal alloys, polymers, bioceramics and natural materials. Because of corrosion and friction in the human body, implants generate debris. This debris may develop toxicity, inflammation and prosthetic unsealing by osseous dissolution. Nature, size, morphology and amount of debris are the parameters influencing the tissue responses. In this paper, we characterised metallic contamination produced by knee prosthesis, composed with TiAl 6V 4 or Co-Cr-Mo alloys, into surrounding capsular tissue by depth migration, in vivo behaviour, content, size and nature of debris by PIXE (Particle Induced X-ray Emission) method associated with RBS (Rutherford Backscattering Spectroscopy). Debris distribution in the whole articulation is very heterogeneous. Debris migrates several thousand micrometers in tissues, with a characteristic decrease. Solid metallic particles of about micrometer size are found in the most polluted samples, in both alloys TiAl 6V 4 and Cr-Co-Mo. In the mean volume analysed by PIXE, the concentration mass ratios [Ti]/[V] and [Co]/[Cr] confirm the chemical stability of TiAl 6V 4 debris and show the chemical evolution of Cr-Co-Mo debris. Development of a protocol to prepare thin targets permits us to correlate PIXE and histological analysis in the same zone. The fibrous tissue (collagen fibres, fibroblasts) and macrophage cells are observed with optical microscope in polluted areas. This protocol could locate other pathologies in ppm contamination range, thanks to the great sensitivity of the PIXE method.

  11. EFFECT OF SOIL MODIFYING FACTORS ON THE BIOAVAILABILITY AND TOXICITY OF METAL CONTAMINATED SOILS

    EPA Science Inventory

    Heavy metal and organic chemical contamination of soils is a worldwide problem posing a risk to humans and more directly, soil organisms. Metal toxicity is often not directly related to the total concentration of metals present due to a number of modifying factors that depend,...

  12. Repeated phytoextraction of four metal-contaminated soils using the cadmium/zinc hyperaccumulator Sedum plumbizincicola.

    PubMed

    Li, Zhu; Wu, Longhua; Hu, Pengjie; Luo, Yongming; Zhang, Hao; Christie, Peter

    2014-06-01

    A cadmium/zinc hyperaccumulator extracted metals from four contaminated soils over three years in a glasshouse experiment. Changes in plant metal uptake and soil total (aqua regia-extractable) and available metals were investigated. Plant Cd concentrations in a high-Cd acid soil and plant Zn concentrations in two acid soils decreased during repeated phytoextraction and were predicted by soil available metal concentrations. However, on repeated phytoextraction, plant Cd concentrations remained constant in lightly Cd-polluted acid soils, as did plant Cd and Zn in alkaline soils, although soil available metal concentrations decreased markedly. After phytoextraction acid soils showed much higher total metal removal efficiencies, indicating possible suitability of phytoextraction for acid soils. However, DGT-testing, which takes soil metal re-supply into consideration, showed substantial removal of available metal and distinct decreases in metal supply capacity in alkaline soils after phytoextraction, suggesting that a strategy based on lowering the bioavailable contaminant might be feasible. PMID:24675367

  13. Metallurgical Laboratory Hazardous Waste Management Facility groundwater monitoring report. Second quarter 1993

    SciTech Connect

    Thompson, C.Y.

    1993-09-01

    During second quarter 1993, samples from AMB groundwater monitoring wells at the metallurgical Laboratory Hazardous Waste Management Facility (HWMF) were analyzed for certain heavy metals, indicator parameters, radionuclides, volatile organic compounds, and other constituents. Six parameters exceeded standards during the quarter. As in previous quarters, tetrachloroethylene and trichloroethylene exceeded final Primary Drinking Water Standards (PDWS), and pH and total organic halogens exceeded the Savannah River Site (SRS) Flag 2 criteria in one or more of the wells. Dichloromethane (methylene chloride), a common laboratory contaminant which was first compared to its final PDWS during first quarter 1993, was elevated in three wells.

  14. Influence of dissimilatory metal reduction on fate of organic and metal contaminants in the subsurface

    NASA Astrophysics Data System (ADS)

    Lovley, Derek R.; Anderson, Robert T.

    Dissimilatory Fe(III)-reducing microorganisms have the ability to destroy organic contaminants under anaerobic conditions by oxidizing them to carbon dioxide. Some Fe(III)-reducing microorganisms can also reductively dechlorinate chlorinated contaminants. Fe(III)-reducing microorganisms can reduce a variety of contaminant metals and convert them from soluble forms to forms that are likely to be immobilized in the subsurface. Studies in petroleum-contaminated aquifers have demonstrated that Fe(III)-reducing microorganisms can be effective agents in removing aromatic hydrocarbons from groundwater under anaerobic conditions. Laboratory studies have demonstrated the potential for Fe(III)-reducing microorganisms to remove uranium from contaminated groundwaters. The activity of Fe(III)-reducing microorganisms can be stimulated in several ways to enhance organic contaminant oxidation and metal reduction. Molecular analyses in both field and laboratory studies have demonstrated that microorganisms of the genus Geobacter become dominant members of the microbial community when Fe(III)-reducing conditions develop as the result of organic contamination, or when Fe(III) reduction is artificially stimulated. These results suggest that further understanding of the ecophysiology of Geobacter species would aid in better prediction of the natural attenuation of organic contaminants under anaerobic conditions and in the design of strategies for the bioremediation of subsurface metal contamination. Des micro-organismes simulant la réduction du fer ont la capacité de détruire des polluants organiques dans des conditions anérobies en les oxydant en dioxyde de carbone. Certains micro-organismes réducteurs de fer peuvent aussi dé-chlorer par réduction des polluants chlorés. Des micro-organismes réducteurs de fer peuvent réduire tout un ensemble de métaux polluants et les faire passer de formes solubles à des formes qui sont susceptibles d'être immobilisées dans le milieu

  15. Determining contamination level of heavy metals in road dust from busy traffic areas with different characteristics.

    PubMed

    Duong, Trang T T; Lee, Byeong-Kyu

    2011-03-01

    This study identified the levels and sources of heavy metal contamination in road dust from busy traffic areas in a typical industrial city in Korea. This study compared the total concentrations, as determined by aqua regia digestions and atomic absorption spectroscopy, of cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni) in the road dust from areas with different characteristics such as traffic rotaries, downtown areas, circulation roads, and asphalt and concrete highways. The contamination levels of the heavy metals in the road dust were evaluated using the contamination factor and the degree of contamination. The contamination levels of the heavy metals in the road dust were highly dependent on traffic volume and atmospheric dispersion from traffic rotaries. Industrial emissions and the frequency of brake use and vehicles coming to a complete stop were additional factors that affected the contamination levels in downtown areas. The concrete highway had higher contamination levels of the heavy metals than the asphalt highway. Vehicle speed was also a strong contributing factor to the degree of contamination of heavy metals in the road dust from the circulation roads and highways. PMID:20937547

  16. Risk perception of heavy metal soil contamination and attitudes toward decontamination strategies.

    PubMed

    Weber, O; Scholz, R W; Bühlmann, R; Grasmück, D

    2001-10-01

    Contaminated soils are a common environmental risk all over the world. One major source of risk is heavy metal soil contamination caused by industrial emissions. This quasiexperimental study investigated the perception of these risks by exposed and nonexposed people, their attitudes toward bioremediation methods using hyperaccumulating plants, and the influence of long-term aspects of sustainability on the acceptance of bioremediation methods. Major findings were that people living in a contaminated area perceived the risk of the heavy metal soil contamination as higher than the general risk of contamination. Second, a factor analysis showed that the factors dread, control, and catastrophic potential were relevant for the perception and valuation of low-dose environmental risks such as the contamination of the investigated area. In addition, a cluster analysis showed that the risk of heavy metal soil contamination was perceived as similar to that of oil contamination, ozone layer, preservatives and genetic technology. It was perceived indifferently with regard to dread. The uncontrollability of heavy metal soil contamination was estimated as medium, and its catastrophic potential as low. Third, exposed and nonexposed participants preferred bioremediation methods to classical methods (e.g., excavation and chemical treatment of the soil), because they perceived the environmental and esthetical performance of the bioremediation as important criteria. Sustainability or precautionary issues, such as the prevention of harm for future generations, were highly correlated with the acceptance of the use of bioremediation methods in people's residential areas. PMID:11798130

  17. Phytotoxicity of trace metals in spiked and field-contaminated soils: Linking soil-extractable metals with toxicity.

    PubMed

    Hamels, Fanny; Malevé, Jasmina; Sonnet, Philippe; Kleja, Dan Berggren; Smolders, Erik

    2014-11-01

    Soil tests have been widely developed to predict trace metal uptake by plants. The prediction of metal toxicity, however, has rarely been tested. The present study was set up to compare 8 established soil tests for diagnosing phytotoxicity in contaminated soils. Nine soils contaminated with Zn or Cu by metal mining, smelting, or processing were collected. Uncontaminated reference soils with similar soil properties were sampled, and series of increasing contamination were created by mixing each with the corresponding soil. In addition, each reference soil was spiked with either ZnCl2 or CuCl2 at several concentrations. Total metal toxicity to barley seedling growth in the field-contaminated soils was up to 30 times lower than that in corresponding spiked soils. Total metal (aqua regia-soluble) toxicity thresholds of 50% effective concentrations (EC50) varied by factors up to 260 (Zn) or 6 (Cu) among soils. For Zn, variations in EC50 thresholds decreased as aqua regia > 0.43 M HNO3  > 0.05 M ethylenediamine tetraacetic acid (EDTA) > 1 M NH4 NO3  > cobaltihexamine > diffusive gradients in thin films (DGT) > 0.001 M CaCl2 , suggesting that the last extraction is the most robust phytotoxicity index for Zn. The EDTA extraction was the most robust for Cu-contaminated soils. The isotopically exchangeable fraction of the total soil metal in the field-contaminated soils markedly explained the lower toxicity compared with spiked soils. The isotope exchange method can be used to translate soil metal limits derived from soils spiked with metal salts to site-specific soil metal limits. PMID:25053440

  18. Heavy metal contamination in compost. A possible solution.

    PubMed

    Zennaro, Mariachiara; Cristofori, Fabrizio; Formigoni, Daniele; Frignani, Franco; Pavoni, Bruno

    2005-01-01

    With the objective of improving qualitative characteristics of compost, an analytical survey was carried out in a composting plant in Lombardy (Italy) in all process of production, with particular reference to heavy metals (HM) Zn and Pb. The investigation was principally aimed to study the contents and the accumulation of HM during composting process and to identify a technological solution for reducing HM content in the final product. A merceological analysis of Municipal Solid Waste (MSW) input to the composting plant, a chemical analysis of the organic fraction of MSW after mechanical separation, and a comparison with values reported by some authors, showed that Zn and Pb are significant contaminants, even though concentrations have recently decreased in comparison to previous years. On the basis of Zn and Pb content in raw material input to the plant, an estimate of the theoretical value of Zn and Pb in produced compost was made. The comparison of theoretical values with the real ones, experimentally determined, confirmed that at the end of composting process the concentration is 2.6 times the initial value for Zn and 1.6 times the initial value for Pb, as suggested by some authors. Finally, the analytical investigation of Zn and Pb contents in the compost refining line, carried out by means of sieving tests, showed that by eliminating a fraction of compost < 1 mm, both Zn and Pb, which is the more critical one, can be largely removed, without a substantial yield loss (only 10% of the final product is eliminated). PMID:16485666

  19. Microbial characterization of a radionuclide- and metal-contaminated waste site

    SciTech Connect

    Bolton, H. Jr.; Lumppio, H.L.; Ainsworth, C.C.; Plymale, A.E.

    1993-04-01

    The operation of nuclear processing facilities and defense-related nuclear activities has resulted in contamination of near-surface and deep-subsurface sediments with both radionuclides and metals. The presence of mixed inorganic contaminants may result in undetectable microbial populations or microbial populations that are different from those present in uncontaminated sediments. To determine the impact of mixed radionuclide and metal contaminants on sediment microbial communities, we sampled a processing pond that was used from 1948 to 1975 for the disposal of radioactive and metal-contaminated wastewaters from laboratories and nuclear fuel fabrication facilities on the Hanford Site in Washington State. Because the Hanford Site is located in a semiarid environment with average rainfall of 159 mm/year, the pond dried and a settling basin remained after wastewater input into the pond ceased in 1975. This processing pond basin offered a unique opportunity to obtain near-surface sediments that had been contaminated with both radionuclides and metals for several decades. Our objectives were to determine the viable populations of microorganisms in the sediments and to test several hypotheses about how the addition of both radionuclides and metals influenced the microbial ecology of the sediments. Our first hypothesis was that viable populations of microorganisms would be lower in the more contaminated sediments. Second, we expected that long-term metal exposure would result in enhanced metal resistance. Finally, we hypothesized that microorganisms from the most radioactive sediments should have had enhanced radiation resistance.

  20. Simulation of the mobility of metal - EDTA complexes in groundwater: The influence of contaminant metals

    USGS Publications Warehouse

    Friedly, J.C.; Kent, D.B.; Davis, J.A.

    2002-01-01

    Reactive transport simulations were conducted to model chemical reactions between metal - EDTA (ethylenediaminetetraacetic acid) complexes during transport in a mildly acidic quartz - sand aquifer. Simulations were compared with the results of small-scale tracer tests wherein nickel-, zinc-, and calcium - EDTA complexes and free EDTA were injected into three distinct chemical zones of a plume of sewage-contaminated groundwater. One zone had a large mass of adsorbed, sewage-derived zinc; one zone had a large mass of adsorbed manganese resulting from mildly reducing conditions created bythe sewage plume; and one zone had significantly less adsorbed manganese and negligible zinc background. The chemical model assumed that the dissolution of iron(III) from metal - hydroxypolymer coatings on the aquifer sediments by the metal - EDTA complexes was kinetically restricted. All other reactions, including metal - EDTA complexation, zinc and manganese adsorption, and aluminum hydroxide dissolution were assumed to reach equilibrium on the time scale of transport; equilibrium constants were either taken from the literature or determined independently in the laboratory. A single iron(III) dissolution rate constant was used to fit the breakthrough curves observed in the zone with negligible zinc background. Simulation results agreed well with the experimental data in all three zones, which included temporal moments derived from breakthrough curves at different distances downgradient from the injections and spatial moments calculated from synoptic samplings conducted at different times. Results show that the tracer cloud was near equilibrium with respect to Fe in the sediment after 11 m of transport in the Zn-contaminated region but remained far from equilibrium in the other two zones. Sensitivity studies showed that the relative rate of iron(III) dissolution by the different metal - EDTA complexes was less important than the fact that these reactions are rate controlled. Results

  1. SORBENTS FOR FLUORIDE, METAL FINISHING, AND PETROLEUM SLUDGE LEACHATE CONTAMINANT CONTROL

    EPA Science Inventory

    This report covers the initial laboratory studies carried out to identify the most promising sorbents that may be used to significantly reduce the concentration of measurable contaminant in calcium fluoride sludge leachate, metal finishing sludge leachate, and petroleum sludge le...

  2. Influence of dissimilatory metal reduction on fate of organic and metal contaminants in the subsurface

    NASA Astrophysics Data System (ADS)

    Lovley, Derek R.; Anderson, Robert T.

    Dissimilatory Fe(III)-reducing microorganisms have the ability to destroy organic contaminants under anaerobic conditions by oxidizing them to carbon dioxide. Some Fe(III)-reducing microorganisms can also reductively dechlorinate chlorinated contaminants. Fe(III)-reducing microorganisms can reduce a variety of contaminant metals and convert them from soluble forms to forms that are likely to be immobilized in the subsurface. Studies in petroleum-contaminated aquifers have demonstrated that Fe(III)-reducing microorganisms can be effective agents in removing aromatic hydrocarbons from groundwater under anaerobic conditions. Laboratory studies have demonstrated the potential for Fe(III)-reducing microorganisms to remove uranium from contaminated groundwaters. The activity of Fe(III)-reducing microorganisms can be stimulated in several ways to enhance organic contaminant oxidation and metal reduction. Molecular analyses in both field and laboratory studies have demonstrated that microorganisms of the genus Geobacter become dominant members of the microbial community when Fe(III)-reducing conditions develop as the result of organic contamination, or when Fe(III) reduction is artificially stimulated. These results suggest that further understanding of the ecophysiology of Geobacter species would aid in better prediction of the natural attenuation of organic contaminants under anaerobic conditions and in the design of strategies for the bioremediation of subsurface metal contamination. Des micro-organismes simulant la réduction du fer ont la capacité de détruire des polluants organiques dans des conditions anérobies en les oxydant en dioxyde de carbone. Certains micro-organismes réducteurs de fer peuvent aussi dé-chlorer par réduction des polluants chlorés. Des micro-organismes réducteurs de fer peuvent réduire tout un ensemble de métaux polluants et les faire passer de formes solubles à des formes qui sont susceptibles d'être immobilisées dans le milieu

  3. Detection of Metal Contamination on Silicon Wafer Backside and Edge by New TXRF Methods

    NASA Astrophysics Data System (ADS)

    Kohno, Hiroshi; Yamagami, Motoyuki; Formica, Joseph; Shen, Liyong

    2009-09-01

    In conventional 200 mm wafer processing, backside defects are not considered to be of much concern because they are obscured by wafer backside topography. However, in current 300 mm wafer processing where both sides of a wafer are polished, backside defects require more consideration. In the beginning, backside defect inspection examined particle contamination because particle contamination adversely influences the depth of field in lithography. Recently, metal contamination is of concern because backside metal contamination causes cross-contamination in a process line, and backside metals easily transfer to the front surface. As the industry strives to yield more devices from the area around the wafer edge, edge exclusion requirements have also become more important. The current International Technology Roadmap for Semiconductors [1] requires a 2 mm edge exclusion. Therefore, metal contamination must be controlled to less than 2 mm from the edge because metal contamination easily diffuses in silicon wafers. To meet these current semiconductor processing requirements, newly developed zero edge exclusion TXRF (ZEE-TXRF) and backside measurement TXRF (BAC-TXRF) are effective metrology methods.

  4. Assessing the bioavailability and risk from metal contaminated soils and dusts#

    EPA Science Inventory

    Exposure to contaminated soil and dust is an important pathway in human and ecological risk assessment and often is the "risk-driver" for metal contaminated soil. Site-specific soil physical and chemical characteristics, as well as biological factors, determine the bioavailabilit...

  5. Draft Genome Sequences of 10 Microbacterium spp., with Emphasis on Heavy Metal-Contaminated Environments

    PubMed Central

    Corretto, Erika; Antonielli, Livio; Sessitsch, Angela; Kidd, Petra; Weyens, Nele

    2015-01-01

    Microbacterium spp. isolated from heavy metal (HM)-contaminated environments (soil and plants) can play a role in mobilization processes and in the phytoextraction of HM. Here, we report the whole-genome sequences and annotation of 10 Microbacterium spp. isolated from both HM-contaminated and -noncontaminated compartments. PMID:25977426

  6. Assessment of a mussel as a metal bioindicator of coastal contamination: relationships between metal bioaccumulation and multiple biomarker responses.

    PubMed

    Chandurvelan, Rathishri; Marsden, Islay D; Glover, Chris N; Gaw, Sally

    2015-04-01

    This is the first study to use a multiple biomarker approach on the green-lipped mussel, Perna canaliculus to test its feasibility as a bioindicator of coastal metal contamination in New Zealand (NZ). Mussels were collected from six low intertidal sites varying in terms of anthropogenic impacts, within two regions (West Coast and Nelson) of the South Island of NZ. Trace elements, including arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn), were measured in the gills, digestive gland, foot and mantle, and in the surface sediments from where mussels were collected. Metal levels in the sediment were relatively low and there was only one site (Mapua, Nelson) where a metal (Ni) exceeded the Australian and New Zealand Interim Sediment Quality Guideline values. Metal levels in the digestive gland were generally higher than those from the other tissues. A variety of biomarkers were assessed to ascertain mussel health. Clearance rate, a physiological endpoint, correlated with metal level in the tissues, and along with scope for growth, was reduced in the most contaminated site. Metallothionein-like protein content and catalase activity in the digestive gland, and catalase activity and lipid peroxidation in the gill, were also correlated to metal accumulation. Although there were few regional differences, the sampling sites were clearly distinguishable based on the metal contamination profiles and biomarker responses. P. canaliculus appears to be a useful bioindicator species for coastal habitats subject to metal contamination. In this study tissue and whole organism responses provided insight into the biological stress responses of mussels to metal contaminants, indicating that such measurements could be a useful addition to biomonitoring programmes in NZ. PMID:25596351

  7. Heavy Metal Contamination Assessment and Partition for Industrial and Mining Gathering Areas

    PubMed Central

    Guan, Yang; Shao, Chaofeng; Ju, Meiting

    2014-01-01

    Industrial and mining activities have been recognized as the major sources of soil heavy metal contamination. This study introduced an improved Nemerow index method based on the Nemerow and geo-accumulation index. Taking a typical industrial and mining gathering area in Tianjin (China) as example, this study then analyzed the contamination sources as well as the ecological and integrated risks. The spatial distribution of the contamination level and ecological risk were determined using Geographic Information Systems. The results are as follows: (1) Zinc showed the highest contaminant level in the study area; the contamination levels of the other seven heavy metals assessed were relatively lower. (2) The combustion of fossil fuels and emissions from industrial and mining activities were the main sources of contamination in the study area. (3) The overall contamination level of heavy metals in the study area ranged from heavily contaminated to extremely contaminated and showed an uneven distribution. (4) The potential ecological risk showed an uneven distribution, and the overall ecological risk level ranged from low to moderate. This study also emphasized the importance of partition in industrial and mining areas, the extensive application of spatial analysis methods, and the consideration of human health risks in future studies. PMID:25032743

  8. Challenges and opportunities in the phytoremediation of heavy metals contaminated soils: A review.

    PubMed

    Mahar, Amanullah; Wang, Ping; Ali, Amjad; Awasthi, Mukesh Kumar; Lahori, Altaf Hussain; Wang, Quan; Li, Ronghua; Zhang, Zengqiang

    2016-04-01

    Mining operations, industrial production and domestic and agricultural use of metal and metal containing compound have resulted in the release of toxic metals into the environment. Metal pollution has serious implications for the human health and the environment. Few heavy metals are toxic and lethal in trace concentrations and can be teratogenic, mutagenic, endocrine disruptors while others can cause behavioral and neurological disorders among infants and children. Therefore, remediation of heavy metals contaminated soil could be the only effective option to reduce the negative effects on ecosystem health. Thus, keeping in view the above facts, an attempt has been made in this article to review the current status, challenges and opportunities in the phytoremediation for remediating heavy metals from contaminated soils. The prime focus is given to phytoextraction and phytostabilization as the most promising and alternative methods for soil reclamation. PMID:26741880

  9. Influence of Microbial Iron and Nitrate Reduction on Subsurface Iron Biogeochemistry and Contaminant Metal Mobilization

    SciTech Connect

    Flynn Picardal

    2002-04-14

    Although toxic metal and radionuclide contaminants can not be destroyed, their toxicity and mobility can be dramatically altered by microbial activity. In addition to toxic metals, many contaminated sites contain both iron-containing minerals and co-contaminants such as nitrate (NO3-). Successful implementation of metal and radionuclide bioremediation strategies in such environments requires an understanding of the complex microbial and geochemical interactions that influence the redox speciation and mobility of toxic metals. Our specific objectives have been to (1) determine the effect of iron oxide mineral reduction on the mobility of sorbed, representative toxic metals (Zn2+), (2) study the biogeochemical interactions that may occur during microbial reduction of NO3- and iron oxide minerals, and (3) evaluate the kinetics of NO3--dependent, microbial oxidation of ferrous iron (Fe2+).

  10. Influence of Microbial Iron and Nitrate Reduction on Subsurface Iron Biogeochemistry and Contaminant Metal Mobilization

    SciTech Connect

    Flynn W. Picardal

    2002-04-10

    Although toxic metal and radionuclide contaminants can not be destroyed, their toxicity and mobility can be dramatically altered by microbial activity. In addition to toxic metals, many contaminated sites contain both iron-containing minerals and co-contaminants such as nitrate NO{sub 3}{sup -}. Successful implementation of metal and radionuclide bioremediation strategies in such environments requires an understanding of the complex microbial and geochemical interactions that influence the redox speciation and mobility of toxic metals. Our specific objectives have been to (1) determine the effect of iron oxide mineral reduction on the mobility of sorbed, representative toxic metals (Zn{sup 2+}), (2) study the biogeochemical interactions that may occur during microbial reduction of NO{sub 3}{sup -} and iron oxide minerals, and (3) evaluate the kinetics of NO{sub 3}{sup -}-dependent, microbial oxidation of ferrous iron (Fe{sup 2+}).

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

    USGS Publications Warehouse

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

    1991-01-01

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

  12. Assessing microbial activities in metal contaminated agricultural volcanic soils - An integrative approach.

    PubMed

    Parelho, C; Rodrigues, A S; Barreto, M C; Ferreira, N G C; Garcia, P

    2016-07-01

    Volcanic soils are unique naturally fertile resources, extensively used for agricultural purposes and with particular physicochemical properties that may result in accumulation of toxic substances, such as trace metals. Trace metal contaminated soils have significant effects on soil microbial activities and hence on soil quality. The aim of this study is to determine the soil microbial responses to metal contamination in volcanic soils under different agricultural land use practices (conventional, traditional and organic), based on a three-tier approach: Tier 1 - assess soil microbial activities, Tier 2 - link the microbial activity to soil trace metal contamination and, Tier 3 - integrate the microbial activity in an effect-based soil index (Integrative Biological Response) to score soil health status in metal contaminated agricultural soils. Our results showed that microbial biomass C levels and soil enzymes activities were decreased in all agricultural soils. Dehydrogenase and β-glucosidase activities, soil basal respiration and microbial biomass C were the most sensitive responses to trace metal soil contamination. The Integrative Biological Response value indicated that soil health was ranked as: organic>traditional>conventional, highlighting the importance of integrative biomarker-based strategies for the development of the trace metal "footprint" in Andosols. PMID:27057992

  13. A geomorphological approach to the management of rivers contaminated by metal mining

    NASA Astrophysics Data System (ADS)

    Macklin, M. G.; Brewer, P. A.; Hudson-Edwards, K. A.; Bird, G.; Coulthard, T. J.; Dennis, I. A.; Lechler, P. J.; Miller, J. R.; Turner, J. N.

    2006-09-01

    As the result of current and historical metal mining, river channels and floodplains in many parts of the world have become contaminated by metal-rich waste in concentrations that may pose a hazard to human livelihoods and sustainable development. Environmental and human health impacts commonly arise because of the prolonged residence time of heavy metals in river sediments and alluvial soils and their bioaccumulatory nature in plants and animals. This paper considers how an understanding of the processes of sediment-associated metal dispersion in rivers, and the space and timescales over which they operate, can be used in a practical way to help river basin managers more effectively control and remediate catchments affected by current and historical metal mining. A geomorphological approach to the management of rivers contaminated by metals is outlined and four emerging research themes are highlighted and critically reviewed. These are: (1) response and recovery of river systems following the failures of major tailings dams; (2) effects of flooding on river contamination and the sustainable use of floodplains; (3) new developments in isotopic fingerprinting, remote sensing and numerical modelling for identifying the sources of contaminant metals and for mapping the spatial distribution of contaminants in river channels and floodplains; and (4) current approaches to the remediation of river basins affected by mining, appraised in light of the European Union's Water Framework Directive (2000/60/EC). Future opportunities for geomorphologically-based assessments of mining-affected catchments are also identified.

  14. Effects of remediation train sequence on decontamination of heavy metal-contaminated soil containing mercury.

    PubMed

    Hseu, Zeng-Yei; Huang, Yu-Tuan; Hsi, Hsing-Cheng

    2014-09-01

    When a contaminated site contains pollutants including both nonvolatile metals and Hg, one single remediation technology may not satisfactorily remove all contaminants. Therefore, in this study, chemical extraction and thermal treatment were combined as a remediation train to remove heavy metals, including Hg, from contaminated soil. A 0.2 M solution of ethylenediamine tetraacetic acid (EDTA) was shown to be the most effective reagent for extraction of considerable amounts of Cu, Pb, and Zn (> 50%). Hg removal was ineffective using 0.2 M EDTA, but thermogravimetric analysis suggested that heating to 550 degrees C with a heating rate of 5 degrees C/min for a duration of 1 hr appeared to be an effective approach for Hg removal. With the employment of thermal treatment, up to 99% of Hg could be removed. However executing thermal treatment prior to chemical extraction reduced the effectiveness of the subsequent EDTA extraction because nonvolatile heavy metals were immobilized in soil aggregates after the 550 degrees C treatment. The remediation train of chemical extraction followed by thermal treatment appears to remediate soils that have been contaminated by many nonvolatile heavy metals and Hg. Implications: A remediation train conjoining two or more techniques has been initialized to remove multiple metals. Better understandings of the impacts of treatment sequences, namely, which technique should be employed first on the soil properties and the decontamination efficiency, are in high demand. This study provides a strategy to remove multiple heavy metals including Hg from a contaminated soil. The interactions between thermal treatment and chemical extraction on repartitioning of heavy metals was revealed. The obtained results could offer an integrating strategy to remediate the soil contaminated with both heavy metals and volatile contaminants. PMID:25282998

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

    EPA Science Inventory

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

  16. An integrated insight into the response of sedimentary microbial communities to heavy metal contamination

    PubMed Central

    Yin, Huaqun; Niu, Jiaojiao; Ren, Youhua; Cong, Jing; Zhang, Xiaoxia; Fan, Fenliang; Xiao, Yunhua; Zhang, Xian; Deng, Jie; Xie, Ming; He, Zhili; Zhou, Jizhong; Liang, Yili; Liu, Xueduan

    2015-01-01

    Response of biological communities to environmental stresses is a critical issue in ecology, but how microbial communities shift across heavy metal gradients remain unclear. To explore the microbial response to heavy metal contamination (e.g., Cr, Mn, Zn), the composition, structure and functional potential of sedimentary microbial community were investigated by sequencing of 16S rRNA gene amplicons and a functional gene microarray. Analysis of 16S rRNA sequences revealed that the composition and structure of sedimentary microbial communities changed significantly across a gradient of heavy metal contamination, and the relative abundances were higher for Firmicutes, Chloroflexi and Crenarchaeota, but lower for Proteobacteria and Actinobacteria in highly contaminated samples. Also, molecular ecological network analysis of sequencing data indicated that their possible interactions might be enhanced in highly contaminated communities. Correspondently, key functional genes involved in metal homeostasis (e.g., chrR, metC, merB), carbon metabolism, and organic remediation showed a higher abundance in highly contaminated samples, indicating that bacterial communities in contaminated areas may modulate their energy consumption and organic remediation ability. This study indicated that the sedimentary indigenous microbial community may shift the composition and structure as well as function priority and interaction network to increase their adaptability and/or resistance to environmental contamination. PMID:26391875

  17. An integrated insight into the response of sedimentary microbial communities to heavy metal contamination.

    PubMed

    Yin, Huaqun; Niu, Jiaojiao; Ren, Youhua; Cong, Jing; Zhang, Xiaoxia; Fan, Fenliang; Xiao, Yunhua; Zhang, Xian; Deng, Jie; Xie, Ming; He, Zhili; Zhou, Jizhong; Liang, Yili; Liu, Xueduan

    2015-01-01

    Response of biological communities to environmental stresses is a critical issue in ecology, but how microbial communities shift across heavy metal gradients remain unclear. To explore the microbial response to heavy metal contamination (e.g., Cr, Mn, Zn), the composition, structure and functional potential of sedimentary microbial community were investigated by sequencing of 16S rRNA gene amplicons and a functional gene microarray. Analysis of 16S rRNA sequences revealed that the composition and structure of sedimentary microbial communities changed significantly across a gradient of heavy metal contamination, and the relative abundances were higher for Firmicutes, Chloroflexi and Crenarchaeota, but lower for Proteobacteria and Actinobacteria in highly contaminated samples. Also, molecular ecological network analysis of sequencing data indicated that their possible interactions might be enhanced in highly contaminated communities. Correspondently, key functional genes involved in metal homeostasis (e.g., chrR, metC, merB), carbon metabolism, and organic remediation showed a higher abundance in highly contaminated samples, indicating that bacterial communities in contaminated areas may modulate their energy consumption and organic remediation ability. This study indicated that the sedimentary indigenous microbial community may shift the composition and structure as well as function priority and interaction network to increase their adaptability and/or resistance to environmental contamination. PMID:26391875

  18. A comparative study of metal contamination in soil using the borehole method.

    PubMed

    Teh, T L; Rahman, Nik Norulaini Nik Ab; Shahadat, Mohammad; Wong, Y S; Syakir, Muhammad I; Omar, A K Mohd

    2016-07-01

    The present study deals with possible contamination of the soil by metal ions which have been affecting the environment. The concentrations of metal ions in 14 borehole samples were studied using the ICP-OES standard method. The degree of contamination was determined on the basis of single element pollution index (SEPI), combined pollution index (CPI), soil enrichment factor (SEF), and geo-accumulation index (Igeo). Geo-accumulation indices and contamination factors indicated moderate to strong contaminations for eight boreholes (BL-1, BL-2, BL-6, BL-8, BL-9, BL-10, BL-12, and BL-13) while the rest were extremely contaminated. Among all the boreholes, BL-3 and BL-11 demonstrated the highest level of Cd(II) and Pb(II) which were found the most polluted sites. The level of metal contamination was also compared with other countries. The development, variation, and limitations regarding the regulations of soil and groundwater contamination can be provided as a helpful guidance for the risk assessment of metal ions in developing countries. PMID:27295186

  19. Metal release from contaminated coastal sediments under changing pH conditions: Implications for metal mobilization in acidified oceans.

    PubMed

    Wang, Zaosheng; Wang, Yushao; Zhao, Peihong; Chen, Liuqin; Yan, Changzhou; Yan, Yijun; Chi, Qiaoqiao

    2015-12-30

    To investigate the impacts and processes of CO2-induced acidification on metal mobilization, laboratory-scale experiments were performed, simulating the scenarios where carbon dioxide was injected into sediment-seawater layers inside non-pressurized chambers. Coastal sediments were sampled from two sites with different contamination levels and subjected to pre-determined pH conditions. Sediment samples and overlying water were collected for metal analysis after 10-days. The results indicated that CO2-induced ocean acidification would provoke increased metal mobilization causing adverse side-effects on water quality. The mobility of metals from sediment to the overlying seawater was correlated with the reduction in pH. Results of sequential extractions of sediments illustrated that exchangeable metal forms were the dominant source of mobile metals. Collectively, our data revealed that high metal concentrations in overlying seawater released from contaminated sediments under acidic conditions may strengthen the existing contamination gradients in Maluan Bay and represent a potential risk to ecosystem health in coastal environments. PMID:26481412

  20. Health hazards and heavy metals accumulation by summer squash (Cucurbita pepo L.) cultivated in contaminated soils.

    PubMed

    Galal, Tarek M

    2016-07-01

    The present study was carried out to investigate the heavy metal concentration accumulated by summer squash cultivated in contaminated soil and their health hazards for public consumers at south Cairo Province, Egypt. Soil and plants were sampled from contaminated and reference farms, using 1 m(2) quadrats, for biomass estimation and nutrient analysis. The daily intake of metals (DIM) and health risk index (HRI) were estimated. Significant differences in soil variables (except As) between contaminated and reference sites were recognized. Summer squash showed remarkable reduction in fresh and dry biomass, fruit production, and photosynthetic pigments under pollution stress. The inorganic and organic nutrients in the aboveground and belowground parts showed significant reduction in contaminated site. In addition, higher concentrations of heavy metals were accumulated in the edible parts and roots more than shoots. The bioaccumulation factor of summer squash for investigated metals was greater than 1, while the translocation factor did not exceed unity in both contaminated and reference sites. The DIM for all investigated metals in the reference site and in the contaminated site (except Fe and Mn) did not exceed 1 in both adults and children. However, HRI of Ni and Mn in the reference site and Pb, Cd, Cu, Ni, Fe, Mn, and Zn in the contaminated one exceeded unity indicating great potential to pose health risk to the consumers. The author recommends that people living in the contaminated area should not eat large quantities of summer squash, so as to avoid excess accumulation of heavy metals in their bodies. PMID:27344559

  1. Dietary toxicity of field-contaminated invertebrates to marine fish: effects of metal doses and subcellular metal distribution.

    PubMed

    Dang, Fei; Rainbow, Philip S; Wang, Wen-Xiong

    2012-09-15

    There is growing awareness of the toxicological effects of metal-contaminated invertebrate diets on the health of fish populations in metal-contaminated habitats, yet the mechanisms underlying metal bioaccumulation and toxicity are complex. In the present study, marine fish Terapon jurbua terepon were fed a commercial diet supplemented with specimens of the polychaete Nereis diversicolor or the clam Scrobicularia plana, collected from four metal-impacted estuaries (Tavy, Restronguet Creek, West Looe, Gannel) in southwest England, as environmentally realistic metal sources. A comparative toxicological evaluation of both invertebrates showed that fish fed S. plana for 21 d exhibited evident mortality compared to those fed N. diversicolor. Furthermore, a spatial effect on mortality was observed. Differences in metal doses rather than subcellular metal distributions between N. diversicolor and S. plana appeared to be the cause of such different mortalities. Partial least squares regression was used to evaluate the statistical relationship between multiple-metal doses and fish mortality, revealing that Pb, Fe, Cd and Zn in field-collected invertebrates co-varied most strongly with the observed mortality. This study provides a step toward exploring the underlying mechanism of dietary toxicity and identifying the potential causality in complex metal mixture exposures in the field. PMID:22579710

  2. Endophytes and their Potential to Deal with Co-contamination of Organic Contaminants (Toluene) and Toxic Metals (Nickel) during Phytoremediation

    SciTech Connect

    Weyens, N.; van der Lelie, D.; Truyens, S.; Saenen, E.; Boulet, J.; Dupae, J.; Taghavi, S.; Carleer, R.; Vangronsveld, J.

    2011-01-15

    The aim was to investigate if engineered endophytes that are capable of degrading organic contaminants, and deal with or ideally improve uptake and translocation of toxic metals, can improve phytoremediation of mixed organic-metal pollution. As a model system, yellow lupine was inoculated with the endophyte Burkholderia cepacia VM1468 possessing (a) the pTOM-Bu61 plasmid, coding for constitutive toluene/TCE degradation, and (b) the chromosomally inserted ncc-nre Ni resistance/sequestration system. As controls, plants were inoculated with B. vietnamiensis BU61 (pTOM-Bu61) and B. cepacia BU72 (containing the ncc-nre Ni resistance/sequestration system). Plants were exposed to mixes of toluene and Ni. Only inoculation with B. cepacia VM1468 resulted in decreased Ni and toluene phytotoxicity, as measured by a protective effect on plant growth and decreased activities of enzymes involved in antioxidative defence (catalase, guaiacol peroxidase, superoxide dismutase) in the roots. Besides, plants inoculated with B. cepacia VM1468 and B. vietnamiensis BU61 released less toluene through the leaves than non-inoculated plants and those inoculated with B. cepacia BU72. Ni-uptake in roots was slightly increased for B. cepacia BU72 inoculated plants. These results indicate that engineered endophytes have the potential to assist their host plant to deal with co-contamination of toxic metals and organic contaminants during phytoremediation.

  3. Chelant extraction of heavy metals from contaminated soils using new selective EDTA derivatives.

    PubMed

    Zhang, Tao; Liu, Jun-Min; Huang, Xiong-Fei; Xia, Bing; Su, Cheng-Yong; Luo, Guo-Fan; Xu, Yao-Wei; Wu, Ying-Xin; Mao, Zong-Wan; Qiu, Rong-Liang

    2013-11-15

    Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid (EDTA) and its salts can substantially increase heavy metal removal from contaminated soils and have been extensively studied for soil washing. However, EDTA has a poor utilization ratio due to its low selectivity resulting from the competition between soil major cations and trace metal ions for chelation. The present study evaluated the potential for soil washing using EDTA and three of its derivatives: CDTA (trans-1,2-cyclohexanediaminetetraacetic acid), BDTA (benzyldiaminetetraacetic acid), and PDTA (phenyldiaminetetraacetic acid), which contain a cylcohexane ring, a benzyl group, and a phenyl group, respectively. Titration results showed that PDTA had the highest stability constants for Cu(2+) and Ni(2+) and the highest overall selectivity for trace metals over major cations. Equilibrium batch experiments were conducted to evaluate the efficacy of the EDTA derivatives at extracting Cu(2+), Zn(2+), Ni(2+), Pb(2+), Ca(2+), and Fe(3+) from a contaminated soil. At pH 7.0, PDTA extracted 1.5 times more Cu(2+) than did EDTA, but only 75% as much Ca(2+). Although CDTA was a strong chelator of heavy metal ions, its overall selectivity was lower and comparable to that of EDTA. BDTA was the least effective extractant because its stability constants with heavy metals were low. PDTA is potentially a practical washing agent for soils contaminated with trace metals. PMID:24076482

  4. Sequential extraction evaluation of heavy-metal-contaminated soil: How clean is clean?

    SciTech Connect

    Li, Wen; Peters, R.W.; Brewster, M.D.; Miller, G.A.

    1995-07-01

    As a result of industrial and military operations, large amounts of land have become contaminated with heavy metals. A growing public awareness of metal toxicity in soils and water has forced increased treatment and improved remediation techniques. To develop an adequate knowledge base to definitively judge the usefulness of the remediation technology requires some basic research in how the contaminants are bound in the soil. In this study, the classic five-step sequential extractions were performed on heavy-metal-contaminated soil from Aberdeen Proving Ground to determine the speciation of the metal forms. This technique speciates the heavy metal distribution into an easily extractable (exchangeable) form, carbonates, reducible oxides, organically-bound forms, and residual forms. In order to compare the results of these fractionations with the amount of heavy metals extracted by chelating agents, multi-stage extractions with EDTA were also performed. The results were used to determine the feasibility of using soil washing and soil flushing techniques for remediating the Aberdeen metals-contaminated soils.

  5. Heavy metal-immobilizing organoclay facilitates polycyclic aromatic hydrocarbon biodegradation in mixed-contaminated soil.

    PubMed

    Biswas, Bhabananda; Sarkar, Binoy; Mandal, Asit; Naidu, Ravi

    2015-11-15

    Soils contaminated with a mixture of heavy metals and polycyclic aromatic hydrocarbons (PAHs) pose toxic metal stress to native PAH-degrading microorganisms. Adsorbents such as clay and modified clay minerals can bind the metal and reduce its toxicity to microorganisms. However, in a mixed-contaminated soil, an adsorption process more specific to the metals without affecting the bioavailability of PAHs is desired for effective degradation. Furthermore, the adsorbent should enhance the viability of PAH-degrading microorganisms. A metal-immobilizing organoclay (Arquad(®) 2HT-75-bentonite treated with palmitic acid) (MIOC) able to reduce metal (cadmium (Cd)) toxicity and enhance PAH (phenanthrene) biodegradation was developed and characterized in this study. The MIOC differed considerably from the parent clay in terms of its ability to reduce metal toxicity (MIOC>unmodified bentonite>Arquad-bentonite). The MIOC variably increased the microbial count (10-43%) as well as activities (respiration 3-44%; enzymatic activities up to 68%), and simultaneously maintained phenanthrene in bioavailable form in a Cd-phenanthrene mixed-contaminated soil over a 21-day incubation period. This study may lead to a new MIOC-assisted bioremediation technique for PAHs in mixed-contaminated soils. PMID:26022853

  6. Partitioning of heavy metals in a soil contaminated by slag: A redistribution study

    SciTech Connect

    Bunzl, K.; Trautmannsheimer, M.; Schramel, P.

    1999-08-01

    In order to interpret reasonably the partitioning of heavy metals in a contaminated soil as observed from applying a sequential extraction procedure, information on possible redistribution processes of the metals during the various extraction steps is essential. For this purpose, sequential extraction was used to study the chemical partitioning of Ag, Cu, Ni, Pb, and Zn in a soil contaminated wither by a slag from coal firing or by a slag from pyrite roasting. Through additional application of sequential extraction to the pure slags as well as to the uncontaminated soil, it was shown that during the various extraction steps applied to the soil/slag mixtures, substantial redistribution processes of the metals between the slag- and soil particles can occur. In many cases, metals ions released during the extraction with acid hydroxylamine or acid hydrogen peroxide are partially readsorbed by solid constituents of the mixture and will therefore be found in the subsequent fractions extracted. As a result, one has to realize that (1) it will be difficult to predict the chemical partitioning of these metals in contaminated soils by investigating pure slags only, and (2) information on the partitioning of a metal in a slag contaminated soil will not necessarily give any relevant information on the form of this metal in the slag or in the slag/soil mixture, because the redistribution processes during sequential extraction will not be the same as those occurring in the soil solution under natural conditions.

  7. Sediment and porewater geochemistry in a metal contaminated estuary, Dulas Bay, Anglesey.

    PubMed

    Sullivan, Paul; Taylor, Kevin G

    2003-03-01

    Remobilisation of contaminant metals from sediments can occur by chemical, biological or physical changes. This in turn can lead to contaminant fluxes to the porewaters and ultimately the water column. The aim of the research presented here is to document post-depositional controls on metal mobility and fluxes in a heavily metal-contaminated estuary. This will allow for an improved understanding of the impact of contaminated sediments on water quality from both a short-term and long-term perspective. Dulas Bay is situated on the east coast of Anglesey, North Wales, and receives polluted waters from Parys Mountain. Metals within Dulas Bay sediments show surface enrichment and variations in mineralogical form. Diagenesis clearly plays a role in post-depositional behaviour of the metals, forming sulphides and potentially carbonates. The presence of a dominant exchangeable/carbonate fraction, and elevated porewater metals, in this sulphidic system is significant and could indicate the presence of freshwater diagenesis, or, reflect the high levels of metals in the sediment. PMID:12901086

  8. Biomonitoring of metal contamination in estuarine ecosystem using seagrass.

    PubMed

    Ahmad, Faridahanim; Azman, Shamila; Said, Mohd Ismid Mohd; Baloo, Lavania

    2015-01-01

    Metals concentrations (As, Cd, Cu, Hg and Pb) in seawater, sediment and the seagrass (Enhalus acoroides) were analysed at Pulai River estuary, Johor Straits, Malaysia. In this research, Enhalus acoroides was used in order to find it's efficiency in up taking metals with a role in phytoremediation. Seawater, sediment and Enhalus acoroides samples were collected, and data of Pearson's correlation coefficients were analysed using SPSS 16 software. Results show that lead levels were the highest metal content in Enhalus acoroides (202 ± 102 μg/gDW), seawater (268 ± 190 μg/L) and sediment (248 ± 218 μg/gDW), compared to other metals. There was a positive correlation for metal concentrations between Enhalus acoroides and sediment, but no correlation was found between Enhalus acoroides with seawater at estuarine area may be caused by inconsistent metal concentrations in seawater due to the influences of tidal changes and stormy waves. This indicates that Enhalus acoroides is a species possessing the capabilities to uptake metals from sediment, and suitable to act as both a phytoremediator and biomonitor in estuarine ecosystems due to sharp sensitivity to variation in the environment. PMID:26029376

  9. Risk assessment for chemical pickling of metals contaminated by radioactive materials.

    PubMed

    Donzella, A; Formisano, P; Giroletti, E; Zenoni, A

    2007-01-01

    In recent years, many cases of contamination of metal scraps by unwanted radioactive materials have occurred. Moreover, international organisations are evaluating the possibility to re-use or to recycle metals coming from nuclear power plants. The metal recycling industry has started to worry about radiation exposure of workers that could be in contact with contaminated metals during each manufacturing phase. Risks are strongly dependent on the radiation source features. The aim of this study is to perform risk assessment for workers involved in chemical pickling of steel coils. Monte Carlo simulations have been performed, using the MCNP package and considering coils contaminated with (60)Co, (137)Cs, (241)Am and (226)Ra. Under the most conservative conditions (coil contaminated with 1.0 kBq g(-1) of (60)Co), the dose assessment results lower than the European dose limit for the population (1 mSv y(-1)), considering a maximum number of 10 contaminated coils handled per year. The only exception concerns the case of (241)Am, for which internal contamination could be non- negligible and should be verified in the specific cases. In every case, radiation exposure risk for people standing at 50 m from the coil is widely <1 mSv y(-1). PMID:16849378

  10. Metallic contaminant detection system using multi-channel high Tc SQUIDs

    NASA Astrophysics Data System (ADS)

    Tanaka, Saburo; Kitamura, Yoshihiro; Hatsukade, Yoshimi; Ohtani, Takeyoshi; Suzuki, Shuichi

    2012-10-01

    We have developed the magnetic metallic contaminant detectors using multiple high Tc SQUID gradiometers for industrial products. Finding ultra-small metallic contaminants is a big issue for manufacturers producing commercial products. The quality of industrial products such as lithium ion batteries can deteriorate by the inclusion of tiny metallic contaminants. When the contamination does occur, the manufacturer of the product suffers a great loss to recall the tainted products. Metallic particles with outer dimension less than 50 μm cannot be detected by a conventional X-ray imaging. Therefore a high sensitive detection system for small foreign matters is required. However, in most of the cases, the matrix of an active material coated sheet electrode is magnetized and the magnetic signal from the matrix is large enough to mask the signal from contaminants. Thus we have developed a detection system based on a SQUID gradiometer and a horizontal magnetization to date. For practical use, we should increase the detection width of the system by employing multiple sensors. We successfully realized an eight-channel high-Tc SQUID gradiometer system for inspection of sheet electrodes of a lithium ion battery with width of at least 60 to 70 mm. Eight planar SQUID gradiometers were mounted with a separation of 9.0 mm. As a result, small iron particles of less than 50 μm were successfully measured. This result suggests that the system is a promising tool for the detection of contaminants in a lithium ion battery.

  11. Assessment of metal contamination, bioavailability, toxicity and bioaccumulation in extreme metallic environments (Iberian Pyrite Belt) using Corbicula fluminea.

    PubMed

    Bonnail, E; Sarmiento, A M; DelValls, T A; Nieto, J M; Riba, I

    2016-02-15

    The Iberian Pyrite Belt (SW Iberian Peninsula) has intense mining activity. Currently, its fluvial networks receive extremely acid lixiviate residue discharges that are rich in sulphates and metals in solution (acid mine drainage, AMD) from abandoned mines. In the current study, the sediment and water quality were analysed in three different areas of the Odiel River to assess the risk associated with the metal content and its speciation and bioavailability. Furthermore, sediment contact bioassays were performed using the freshwater clam Corbicula fluminea to determine its adequacy as a biomonitoring tool in relation to theoretical risk indexes and regulatory thresholds. Reburial activity and mortality were used as the toxic responses of clams when exposed to contaminated sediment. The results showed coherence between the water and sediment chemical contamination for most of the metals. The reburial activity was correlated with the metal toxicity, but no clam mortality was registered. The bioaccumulation of the studied metals in the clam did not have a significant correlation with the bioavailable fraction of the metal content in the environment, which could be related to a potential different speciation in this singular environment. The bioaccumulation responses were negative for As, Cd and Zn in highly contaminated environments and were characterized as severe, considerable and low potential environmental risks, respectively. The results show that C. fluminea is a good biomonitor of Cu and Pb. PMID:26774961

  12. DOWN-STREAM SPATIAL DISTRIBUTION OF ANTIBIOTIC RESISTANCE TRAITS ALONG METAL CONTAMINATED STREAM REACHES

    SciTech Connect

    Tuckfield, C; J V Mcarthur , J

    2007-04-16

    Sediment bacteria samples were collected from three streams in South Carolina, two contaminated with multiple metals (Four Mile Creek and Castor Creek), one uncontaminated (Meyers Branch), and another metal contaminated stream (Lampert Creek) in northern Washington State. Growth plates inoculated with Four Mile Creek sample extracts show bacteria colony growth after incubation on plates containing either one of two aminoglycosides (kanamycin or streptomycin), tetracycline or chloramphenocol. This study analyzes the spatial pattern of antibiotic resistance in culturable sediment bacteria in all four streams that may be due to metal contamination. We summarize the two aminoglycoside resistance measures and the 10 metals concentrations by Principal Components Analysis. Respectively, 63% and 58% of the variability was explained in the 1st principal component of each variable set. We used the respective multivariate summary metrics (i.e. 1st principal component scores) as input measures for exploring the spatial correlation between antibiotic resistance and metal concentration for each stream reach sampled. Results show a significant and negative correlation between metals scores versus aminoglycoside resistance scores and suggest that selection for metal tolerance among sediment bacteria may influence selection for antibiotic resistance differently than previously supposed.. In addition, we borrow a method from geostatistics (variography) wherein a spatial cross-correlation analysis shows that decreasing metal concentrations scores are associated with increasing aminoglycoside resistance scores as the separation distance between sediment samples decreases, but for contaminated streams only. Since these results were counter to our initial expectation and to other experimental evidence for water column bacteria, we suspect our field results are influenced by metal bioavailability in the sediments and by a contaminant promoted interaction or ''cocktail effect'' from

  13. Comparison of natural organic acids and synthetic chelates at enhancing phytoextraction of metals from a multi-metal contaminated soil.

    PubMed

    do Nascimento, Clístenes Williams A; Amarasiriwardena, Dula; Xing, Baoshan

    2006-03-01

    Chemically assisted phytoremediation has been developing to induce accumulation of metals by high biomass plants. Synthetic chelates have shown high effectiveness to reach such a goal, but they pose serious drawbacks in field application due to the excessive amount of metals solubilized. We compared the performance of synthetic chelates with naturally occurring low molecular weight organic acids (LMWOA) in enhancing phytoextraction of metals by Indian mustard (Brassica juncea) from multi-metal contaminated soils. Gallic and citric acids were able to induce removal of Cd, Zn, Cu, and Ni from soil without increasing the leaching risk. Net removal of these metals caused by LMWOA can be as much as synthetic chelates. A major reason for this is the lower phytotoxicity of LMWOA. Furthermore, supplying appropriate mineral nutrients increased biomass and metal removal. PMID:16125291

  14. Genetic basis and importance of metal resistant genes in bacteria for bioremediation of contaminated environments with toxic metal pollutants.

    PubMed

    Das, Surajit; Dash, Hirak R; Chakraborty, Jaya

    2016-04-01

    Metal pollution is one of the most persistent and complex environmental issues, causing threat to the ecosystem and human health. On exposure to several toxic metals such as arsenic, cadmium, chromium, copper, lead, and mercury, several bacteria has evolved with many metal-resistant genes as a means of their adaptation. These genes can be further exploited for bioremediation of the metal-contaminated environments. Many operon-clustered metal-resistant genes such as cadB, chrA, copAB, pbrA, merA, and NiCoT have been reported in bacterial systems for cadmium, chromium, copper, lead, mercury, and nickel resistance and detoxification, respectively. The field of environmental bioremediation has been ameliorated by exploiting diverse bacterial detoxification genes. Genetic engineering integrated with bioremediation assists in manipulation of bacterial genome which can enhance toxic metal detoxification that is not usually performed by normal bacteria. These techniques include genetic engineering with single genes or operons, pathway construction, and alternations of the sequences of existing genes. However, numerous facets of bacterial novel metal-resistant genes are yet to be explored for application in microbial bioremediation practices. This review describes the role of bacteria and their adaptive mechanisms for toxic metal detoxification and restoration of contaminated sites. PMID:26860944

  15. Contaminated scrap metal management on the Oak Ridge Reservation

    SciTech Connect

    Hayden, H.W.; Stephenson, M.J.; Bailey, J.K.; Weir, J.R.; Gilbert, W.C.

    1993-09-01

    Large quantities of scrap metal are accumulating at the various Department of Energy (DOE) installations across the country as a result of ongoing DOE programs and missions in concert with present day waste management practices. DOE Oak Ridge alone is presently storing around 500,000 tons of scrap metal. The local generation rate, currently estimated at 1,400 tons/yr, is expected to increase sharply over the next couple of years as numerous environmental restoration and decommissioning programs gain momentum. Projections show that 775,000 tons of scrap metal could be generated at the K-25 Site over the next ten years. The Y-12 Plant and Oak Ridge National Laboratory (ORNL) have similar potentials. The history of scrap metal management at Oak Ridge and future challenges and opportunities are discussed.

  16. Plasma treatment of INEL soil contaminated with heavy metals

    SciTech Connect

    Detering, B.A.; Batdorf, J.A.

    1992-01-01

    INEL soil spiked with inorganic salts of chromium, lead, mercury, silver, and zinc was melted in a 150 kW plasma furnace to produce a glassy slag product. This glassy slag is an environmentally safe waste form. In order to reduce the melting temperature of the soil, sodium carbonate was added to half of the test batches. Random sample from each batch of glassy slag product were analyzed by an independent laboratory for total metals concentration and leachability of metals via the Environmental Protection Agency (EPA) toxicity characterization leaching procedure (RCLP) tests. These tests showed the residual metals were very tightly bound to the slag matrix and were within EPA TCLP limits under these test conditions. Additionally, scanning electron microscopy (SEM) and emissions dispersive spectroscopy (EDS) analysis of the vitrified soil also confirmed that the added metals present in the vitrified soil were totally contained in the crystalline phase as distinct oxide crystallites.

  17. Microbial community structures in anoxic freshwater lake sediment along a metal contamination gradient

    PubMed Central

    Gough, Heidi L; Stahl, David A

    2011-01-01

    Contamination, such as by heavy metals, has frequently been implicated in altering microbial community structure. However, this association has not been extensively studied for anaerobic communities, or in freshwater lake sediments. We investigated microbial community structure in the metal-contaminated anoxic sediments of a eutrophic lake that were impacted over the course of 80 years by nearby zinc-smelting activities. Microbial community structure was inferred for bacterial, archaeal and eukaryotic populations by evaluating terminal restriction fragment length polymorphism (TRFLP) patterns in near-surface sediments collected in triplicate from five areas of the lake that had differing levels of metal contamination. The majority of the fragments in the bacterial and eukaryotic profiles showed no evidence of variation in association with metal contamination levels, and diversity revealed by these profiles remained consistent even as metal concentrations varied from 3000 to 27 000 mg kg−1 total Zn, 0.125 to 11.2 μ pore water Zn and 0.023 to 5.40 μ pore water As. Although most archaeal fragments also showed no evidence of variation, the prevalence of a fragment associated with mesophilic Crenarchaeota showed significant positive correlation with total Zn concentrations. This Crenarchaeota fragment dominated the archaeal TRFLP profiles, representing between 35% and 79% of the total measured peak areas. Lake DePue 16S rRNA gene sequences corresponding to this TRFLP fragment clustered with anaerobic and soil mesophilic Crenarchaeota sequences. Although Crenarchaeota have been associated with metal-contaminated groundwater and soils, this is a first report (to our knowledge) documenting potential increased prevalence of Crenarchaeota associated with elevated levels of metal contamination. PMID:20811473

  18. Use of regulatory documents for assessing the contamination of soils with heavy metals

    NASA Astrophysics Data System (ADS)

    Nesterova, O. V.; Tregubova, V. G.; Semal, V. A.

    2014-11-01

    The chronological review and analysis of the existing regulatory documents relevant to the assessment of soil contamination with heavy metals have been presented. Attention has been given to the incorrect use of the term "total heavy metal content" and the method of its determination in a 5 M nitric acid solution recommended by some regulatory documents. The maximum permissible concentrations (MPCs) and tentatively permissible concentrations (TPCTPCs) for the total heavy metal contents are based on the above method; therefore, the conventional methods of determining the true total contents of heavy metals overestimate the degree of contamination. To avoid confusion, it has been proposed to call the content of a heavy metal in a 5 M nitric acid solution the "pseudototal" content and to compare the experimental results with the MPC or TPCTPC values only if the methods recommended by the regulatory documents were used.

  19. Uptake of certain heavy metals from contaminated soil by mushroom--Galerina vittiformis.

    PubMed

    Damodaran, Dilna; Vidya Shetty, K; Raj Mohan, B

    2014-06-01

    Remediation of soil contaminated with heavy metals has received considerable attention in recent years. In this study, the heavy metal uptake potential of the mushroom, Galerina vittiformis, was studied in soil artificially contaminated with Cu (II), Cd (II), Cr (VI), Pb (II) and Zn (II) at concentrations of 50 and 100mg/kg. G. vittiformis was found to be effective in removing the metals from soil within 30 days. The bioaccumulation factor (BAF) for both mycelia and fruiting bodies with respect to these heavy metals at 50mg/kg concentrations were found to be greater than one, indicating hyper accumulating nature by the mushroom. The metal removal rates by G. vittiformis was analyzed using different kinetic rate constants and found to follow the second order kinetic rate equation except for Cd (II), which followed the first order rate kinetics. PMID:24655915

  20. Tungsten- and cobalt-dominated heavy metal contamination of mangrove sediments in Shenzhen, China.

    PubMed

    Xu, Songjun; Lin, Chuxia; Qiu, Penghua; Song, Yan; Yang, Wenhuai; Xu, Guanchang; Feng, Xiaodan; Yang, Qian; Yang, Xiu; Niu, Anyi

    2015-11-15

    A baseline investigation into heavy metal status in the mangrove sediments was conducted in Shenzhen, China where rapid urban development has caused severe environmental contamination. It is found that heavy metal contamination in this mangrove wetland is characterized by the dominant presence of tungsten and cobalt, which is markedly different from the neighboring Hong Kong and other parts of the world. The vertical variation pattern of these two metals along the sediment profile differed from other heavy metals, suggesting an increasing influx of tungsten and cobalt into the investigated mangrove habitat, as a result of uncontrolled discharge of industrial wastewater from factories that produce or use chemical compounds or alloys containing these two heavy metals. Laboratory simulation experiment indicated that seawater had a stronger capacity to mobilize sediment-borne tungsten and cobalt, as compared to deionized water, diluted acetic, sulfuric and nitric acids. PMID:26323860

  1. Growth and survival of Halimione portulacoides stem cuttings in heavy metal contaminated soils.

    PubMed

    Andrades-Moreno, L; Cambrollé, J; Figueroa, M E; Mateos-Naranjo, E

    2013-10-15

    The halophytic shrub Halimione portulacoides demonstrates a high tolerance to heavy metal contamination and a capacity for accumulating metals within its tissues. On the Iberian Peninsula, this species has colonized habitats with high levels of metal pollution. The aim of this study is to analyze the response of H. portulacoides stem cuttings to this pollution. Growth, photosynthesis and metal uptake were examined in H. portulacoides through an experiment in which stem cuttings were replanted in metal-contaminated soil. This condition decreased growth and lowered both photosynthetic rate and stomatal conductance. Reduced photosynthetic performance was largely due to the reduced concentration of photosynthetic pigments. Despite these responses, there was some important evidence suggesting the phytoremediatory potential of Halimione stem cuttings. The results of our study indicate that this salt-marsh shrub may represent a biotool of value in the restoration of polluted areas. PMID:24018174

  2. Metal pollution in a contaminated bay: relationship between metal geochemical fractionation in sediments and accumulation in a polychaete.

    PubMed

    Fan, Wenhong; Xu, Zhizhen; Wang, Wen-Xiong

    2014-08-01

    Jinzhou Bay in Northern China has been seriously contaminated with metals due to the impacts of smelting activities. In this study, we investigated the relationship between metal accumulation in a deposit-feeding polychaete Neanthes japonica and metal concentration and geochemical fractionation (Cd, Cu, Pb, Zn and Ni) in sediments of Jinzhou Bay. Compared with the historical data, metals in the more mobile geochemical fraction (exchangeable and carbonate fractions) were gradually partitioned into the more stable fraction (Fe-Mn oxides) over time. Metal concentration and geochemical fractionation in sediment significantly affected metal bioavailability and accumulation in polychaetes, except for Ni. Metal accumulation in polychaetes was significantly influenced by Fe or Mn content, and to a lesser degree by organic matter. Prediction of metal bioaccumulation in polychaetes was greatly improved by normalizing metal concentrations to Mn content in sediment. The geochemical fractionation of metals in sediments including the exchangeable, organic matter and Fe-Mn oxides were important in controlling the sediment metal bioavailability to polychaetes. PMID:24811945

  3. Effects of heavy metals on earthworms along contamination gradients in organic rich soils.

    PubMed

    Lukkari, Tuomas; Taavitsainen, Mirka; Väisänen, Ari; Haimi, Jari

    2004-11-01

    Earthworm communities and metal (bio)availability to earthworms along contamination gradients was studied in order to support chemical analyses in risk assessment of metal contaminated soils. Earthworms were sampled in three metal contaminated areas with different habitat and soil properties in Finland. Earthworm and soil samples were collected at three distances (1, 2, and 4 km) from the emission sources. Earthworms were identified as to species and analyzed for heavy metals. Total soil metal concentrations were analyzed using an ultrasound-assisted extraction method and bioavailable metal fraction was estimated by acetic acid extraction. In two of the three areas studied, heavy metal concentrations close to the emission sources were high enough to have harmful effects on earthworms and their environments. In general, diversity, total numbers, and biomass of earthworms increased with increasing distance from the emission sources. When individuals were available for analyses close to the emission source, positive correlations between metal concentrations in the earthworms and those in the soils were observed. PMID:15388274

  4. DOE`s radioactively - contaminated metal recycling: The policy and its implementation

    SciTech Connect

    Warren, S.; Rizkalla, E.

    1997-02-01

    In 1994, the Department of Energy`s Office of Environmental Restoration initiated development of a recycling policy to minimize the amount of radioactively-contaminated metal being disposed of as waste. During the following two years, stakeholders (including DOE and contractor personnel, regulators, members of the public, and representatives of labor and industry) were invited to identify key issues of concern, and to provide input on the final policy. As a result of this process, a demonstration policy for recycling radioactively-contaminated carbon steel resulting from decommissioning activities within the Environmental Management program was signed on September 20, 1996. It specifically recognizes that the Office of Environmental Management has a tremendous opportunity to minimize the disposal of metals as waste by the use of disposal containers fabricated from contaminated steel. The policy further recognizes the program`s demand for disposal containers, and it`s role as the major generator of radioactively-contaminated steel.

  5. Trace metals in the surface sediments of the intertidal Jiaozhou Bay, China: Sources and contamination assessment.

    PubMed

    Xu, Fangjian; Qiu, Longwei; Cao, Yingchang; Huang, Jingli; Liu, Zhaoqing; Tian, Xu; Li, Anchun; Yin, Xuebo

    2016-03-15

    The major (Al) and trace metal (Cu, Pb, Zn, Cr, Cd, and As) concentrations in 29 surface sediment samples from the intertidal Jiaozhou Bay (JZB) are evaluated to assess the contamination level. The results show that the overall sediment quality in the area has been obviously impacted by trace metal contamination. The geoaccumulation index and the enrichment factor values indicate that no Cr or Cu contamination has occurred on the whole, only a few stations have been polluted by As, and some areas have been polluted by Cd, Pb, and Zn. Principal component analysis suggests that the Cu, Pb, Zn, and Cd are derived from anthropogenic inputs and that Cr, As, Cu, and Zn are influenced by natural weathering processes. Cu and Zn may originate from both natural and anthropogenic sources. The contamination in the northeastern JZB is higher than that in other areas of the bay. PMID:26806660

  6. Metal-contaminated sediments in a semi-closed basin: Implications for recovery

    NASA Astrophysics Data System (ADS)

    Monterroso, P.; Pato, P.; Pereira, M. E.; Millward, G. E.; Vale, C.; Duarte, A.

    2007-01-01

    Sediment cores, collected from a contaminated zone in the Ria de Aveiro (Portugal), were sectioned, under nitrogen, and centrifuged to remove the pore waters. The sediment characteristics, including acid volatile sulphide (AVS) concentrations, were determined, together with total and available metals (Fe, Mn, Cd, Cu, Pb, Zn) and the total dissolved metals in the pore waters. Peak concentrations in total metals of the sediments were observed at various depths in the core as a result of time-dependent, industrial discharges. The fraction of total metal released by a mixture of hydroxylamine hydrochloride and acetic acid (HAA) ranged from 24% for Cu to 74% for Zn and enzymatic digestion by proteinase K released <10% of total metal. The pore waters had elevated dissolved metal concentrations concomitant with the peaks in total and available metal and with a maximum in AVS concentration. Equilibrium calculations indicated that the major dissolved phase species was MHS 2-, with minor quantities of M(HS) 2. The diffusive fluxes for sediment-water exchange of the metals were insignificant, the mobility of the metals being hindered by sulphide formation. Thus, the metals are likely to remain trapped in these sediments, thereby delaying recovery from contamination.

  7. Lead (Pb) and other metals in New York City community garden soils: factors influencing contaminant distributions.

    PubMed

    Mitchell, Rebecca G; Spliethoff, Henry M; Ribaudo, Lisa N; Lopp, Donna M; Shayler, Hannah A; Marquez-Bravo, Lydia G; Lambert, Veronique T; Ferenz, Gretchen S; Russell-Anelli, Jonathan M; Stone, Edie B; McBride, Murray B

    2014-04-01

    Urban gardens provide affordable fresh produce to communities with limited access to healthy food but may also increase exposure to lead (Pb) and other soil contaminants. Metals analysis of 564 soil samples from 54 New York City (NYC) community gardens found at least one sample exceeding health-based guidance values in 70% of gardens. However, most samples (78%) did not exceed guidance values, and medians were generally below those reported in NYC soil and other urban gardening studies. Barium (Ba) and Pb most frequently exceeded guidance values and along with cadmium (Cd) were strongly correlated with zinc (Zn), a commonly measured nutrient. Principal component analysis suggested that contaminants varied independently from organic matter and geogenic metals. Contaminants were associated with visible debris and a lack of raised beds; management practices (e.g., importing uncontaminated soil) have likely reduced metals concentrations. Continued exposure reduction efforts would benefit communities already burdened by environmental exposures. PMID:24502997

  8. Lead (Pb) and other metals in New York City community garden soils: factors influencing contaminant distributions

    PubMed Central

    Mitchell, Rebecca G.; Spliethoff, Henry M.; Ribaudo, Lisa N.; Lopp, Donna M.; Shayler, Hannah A.; Marquez-Bravo, Lydia G.; Lambert, Veronique T.; Ferenz, Gretchen S.; Russell-Anelli, Jonathan M.; Stone, Edie B.; McBride, Murray B.

    2014-01-01

    Urban gardens provide affordable fresh produce to communities with limited access to healthy food but may also increase exposure to lead (Pb) and other soil contaminants. Metals analysis of 564 soil samples from 54 New York City (NYC) community gardens found at least one sample exceeding health-based guidance values in 70% of gardens. However, most samples (78%) did not exceed guidance values, and medians were generally below those reported in NYC soil and other urban gardening studies. Barium (Ba) and Pb most frequently exceeded guidance values and along with cadmium (Cd) were strongly correlated with zinc (Zn), a commonly measured nutrient. Principal component analysis suggested that contaminants varied independently from organic matter and geogenic metals. Contaminants were associated with visible debris and a lack of raised beds; management practices (e.g., importing uncontaminated soil) have likely reduced metals concentrations. Continued exposure reduction efforts would benefit communities already burdened by environmental exposures. PMID:24502997

  9. Efficiency of non-ionic surfactants - EDTA for treating TPH and heavy metals from contaminated soil

    PubMed Central

    2013-01-01

    Introduction of fuel hydrocarbons and inorganic compounds (heavy metals) into the soil, resulting in a change of the soil quality, which is likely to affect use of the soil or endangering public health and ground water. This study aimed to determine a series of parameters to remediation of TPH and heavy metals contaminated soil by non-ionic surfactants- chelating agents washing process. In this experimental study, the effects of soil washing time, agitation speed, concentration of surfactant, chelating agent and pH on the removal efficiency were studied. The results showed that TPH removal by nonionic surfactants (Tween 80, Brij 35) in optimal condition were 70–80% and 60–65%, respectively. Addition of chelating agent (EDTA) significantly increases Cd and Pb removal. The washing of soil by non- ionic surfactants and EDTA was effective in remediation of TPH and heavy metals from contaminated soil, thus it can be recommended for remediation of contaminated soil. PMID:24359927

  10. Assessment of metal contamination in coastal sediments, seawaters and bivalves of the Mediterranean Sea coast, Egypt.

    PubMed

    El-Sorogy, Abdelbaset S; Attiah, Abdullah

    2015-12-30

    In order to assess metal contamination on the Mediterranean coast of Egypt, 45 sediment samples, seawaters and bivalve specimens were collected from Rosetta coastal area for Mg, Al, K, Fe, Sr, Zn, Pb, Mn, As, Ce, Ni, Cr and Zr analyses by Inductively Coupled Plasma-Mass Spectrometer. The Enrichment Factor (EF), the Geoaccumulation Index (Igeo) and the Contamination Factor (CF) indicated that the coastal sediments of Rosetta area were severely enriched, strongly polluted with As, Pb and very highly contaminated with As, Pb, Ni, Ce, mostly as a result of anthropogenic inputs. Comparison with other samples from the Arabian Gulf, Red Sea and abroad coasts suggested that the studied samples have higher concentrations of Fe, Pb, As, Zn and Ni. The natural sources of heavy metals in the study area are attributed to weathering and decomposition of mountain ranges of the Sudan and Ethiopia, while the anthropogenic ones are the metals produced from industrial, sewage, irrigation and urban runoff. PMID:26563548

  11. Aquatic insects as biomonitors of trace metal contamination

    SciTech Connect

    Popp, C.J.; Lynch, T.R. ); Jacobi, G.Z. )

    1989-01-01

    The concentrations of 13 heavy metals in water, stream sediments, and a variety of aquatic insects in the Red River above and below the Molycorp mine and mill is reported. The mine-mill complex is located between the towns of Red River and Questa and is connected by a pipeline to a tailings disposal pond located about 8 km downstream of Questa. The pipeline is adjacent the Red River. Numerous breaks have occurred in the pipeline in the past resulting in processed milled tailings being discharged directly into the river. Atomic absorption was used for metal analysis. Experimental results are presented.

  12. The role of carbon contamination in voltage linearity and leakage current in high-k metal-insulator-metal capacitors

    NASA Astrophysics Data System (ADS)

    Miao, Bing; Mahapatra, Rajat; Wright, Nick; Horsfall, Alton

    2008-09-01

    The effect of carbon contamination on the electrical properties of metal-insulator-metal (MIM) capacitor using HfO2 dielectric has been reported. The HfO2 film with lower carbon contamination shows an overall high performance, such as a higher capacitance density of 5.21 fF/μm2, a lower leakage current of 1.3×10-7 A/cm2 at 1 V, lower-voltage coefficients of capacitance, and better frequency and temperature dispersion properties compared with the capacitor of theHfO2 film with higher carbon contamination. The calculated ac barrier heights by electrode polarization model from capacitance-voltage (C-V) characteristics are 0.58 eV for the HfO2 film with high carbon contamination and 0.95 eV for the HfO2 film with negligible carbon contamination. The dc barrier heights extracted from current-voltage (I-V) characteristics are 0.26 eV for the HfO2 film with high carbon contamination and 1.1 eV for the HfO2 film with negligible carbon contamination. All of these experimental results exhibit that the increase in defect density in HfO2 films generated from carbon impurities results in the degradation of barrier heights and poor performance of the MIM capacitor. It is important to point out that, during the fabrication process of the MIM capacitor, the carbon contamination must be minimized.

  13. Utilization of grasses for potential biofuel production and phytoremediation of heavy metal contaminated soils.

    PubMed

    Balsamo, Ronald A; Kelly, William J; Satrio, Justinus A; Ruiz-Felix, M Nydia; Fetterman, Marisa; Wynn, Rodd; Hagel, Kristen

    2015-01-01

    This research focuses on investigating the use of common biofuel grasses to assess their potential as agents of long-term remediation of contaminated soils using lead as a model heavy metal ion. We present evidence demonstrating that switch grass and Timothy grass may be potentially useful for long-term phytoremediation of heavy metal contaminated soils and describe novel techniques to track and remove contaminants from inception to useful product. Enzymatic digestion and thermochemical approaches are being used to convert this lignocellulosic feedstock into useful product (sugars, ethanol, biocrude oil+biochar). Preliminary studies on enzymatic hydrolysis and fast pyrolysis of the Switchgrass materials that were grown in heavy metal contaminated soil and non-contaminated soils show that the presence of lead in the Switchgrass material feedstock does not adversely affect the outcomes of the conversion processes. These results indicate that the modest levels of contaminant uptake allow these grass species to serve as phytoremediation agents as well as feedstocks for biofuel production in areas degraded by industrial pollution. PMID:25495935

  14. Chelant extraction and REDOX manipulation for mobilization of heavy metals from contaminated soils

    SciTech Connect

    Brewster, M.D.; Peters, R.W.; Miller, G.A.; Patton, T.L.; Martino, L.E.

    1994-12-01

    Was the result of open burning and open detonation of chemical agents and munitions in the Toxic Burning Pits area at J-Field, located in the Edgewood Area of Aberdeen Proving Ground in Harford County, Maryland, soils have been contaminated with heavy metals. Simultaneous extraction is complicated because of the multitude of contaminant forms that exist. This paper uses data from a treatability study performed at Argonne National Laboratory to discuss and compare several treatment methods that were evaluated for remediating metals-contaminated soils. J-Field soils were subjected to a series of treatability experiments designed to determine the feasibility of using soil washing/soil flushing, enhancements to soil washing/soil flushing, solidification/stabilization, and electrokinetics for remediating soils contaminated with metals. Chelating and mobilizing agents evaluated included ammonium acetate, ethylenediaminetetraacetic acid, citric acid, Citranox, gluconic acid, phosphoric acid, oxalic acid, and nitrilotriacetic acid, in addition to pH-adjusted water. REDOX manipulation can maximize solubilities, increase desorption, and promote removal of heavy metal contaminants. Reducing agents that were studied included sodium borohydride, sodium metabisulfite, and thiourea dioxide. The oxidants studied included hydrogen peroxide, sodium percarbonate, sodium hypochlorite, and potassium permanganate. This paper summaries the results from the physical/chemical characterization, soil washing/soil flushing, and enhancements to soil washing/soil flushing portions of the study.

  15. Remediation of a heavy metal-contaminated soil by means of agglomeration.

    PubMed

    Polettini, Alessandra; Pomi, Raffaella; Valente, Mattia

    2004-01-01

    The feasibility of treating a heavy metal-contaminated soil by means of a solidification/stabilization treatment consisting of a granulation process is discussed in the present article. The aim of the study was to attain contaminant immobilization within the agglomerated solid matrix. The soil under concern was characterized by varying levels of heavy metal contamination, ranging from 50 to 500 mg kg(-1) dry soil for chromium. from 300 to 2000 mg kg(-1) dry soil for lead and from 270 to 5000 mg kg(-1) dry soil for copper. An artificially contaminated soil with contaminant concentrations corresponding to the upper level of the mentioned ranges was prepared from a sample of uncontaminated soil by means of spiking experiments. Pure soluble species of chromium, copper and lead. namely CrCl3.6H2O, CuCl2.2H2O and Pb(NO3)2, were selected for the spiking experiments, which were arranged according to a 2(3) full factorial design. The solidification/stabilization treatment was based on an agglomeration process making use of hydraulic binders including Portland cement, hydrated lime and sodium methasilicate, which were selected on the basis of preliminary test runs. It was found that after 7 days of curing the applied treatment was able to efficiently immobilize the investigated heavy metals within the hydrated matrix. Good acid neutralization behavior was also observed, indicating improved matrix resistance to acid attack and decreased potential for metal leaching. PMID:15137715

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

    PubMed

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

    2014-02-01

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

  17. Source identification study of heavy metal contamination in the industrial hub of Unnao, India.

    PubMed

    Dwivedi, Ashish Kr; Vankar, Padma S

    2014-06-01

    India's Unnao region is home to many leather-treatment facilities and related industries. Industrial and agricultural waste leads to heavy metal contamination that infiltrates groundwater and leads to human health hazards. This work measured the amount of heavy metal in groundwater at specific sites near the industrial facilities in Unnao and identified potential sources of contamination as anthropogenic or lithogenic. Groundwater samples were taken from 10 bore well sites chosen for depth and proximity to industry. Data obtained from sample sites was interpreted using a multivariate statistical analytical approach, i.e., principal component analysis, clustering analysis, and correlation analysis. The results of the multivariate analysis showed that cadmium, copper, manganese, nickel, lead, and zinc were correlated with anthropogenic sources, while iron and chromium were associated with lithogenic sources. These findings provide information on the possible sources of heavy metal contamination and could be a model for assessing and monitoring heavy metal pollution in groundwater in other locales. This study analyzed a selection of heavy metals chosen on the basis of industries located in the study area, which might not provide a complete range of information about the sources and availability of all heavy metals. Therefore, an extended investigation on heavy metal fractions will be developed in further studies. PMID:24488365

  18. Microbe and Mineral Mediated Transformation of Heavy Metals, Radionuclides, and Organic Contaminants

    NASA Astrophysics Data System (ADS)

    Gerlach, R.

    2011-12-01

    Microorganisms influence their surroundings in many ways and humans have utilized microbially catalyzed reactions for benefit for centuries. Over the past few decades, microorganisms have been used for the control of contaminant transport in subsurface environments where many microbe mineral interactions occur. This presentation will discuss microbially influenced mineral formation and transformation as well as their influence on the fate of organic contaminants such as chlorinated aliphatics & 2,4,6-trinitrotoluene (TNT), heavy metals such as chromium, and radionuclides such as uranium & strontium. Both, batch and flow experiments have been performed, which monitor the net effect of microbe mineral interactions on the fate of these contaminants. This invited presentation will place an emphasis on the relative importance of direct microbial (i.e. biotic) transformations, mineral-mediated transformations as well as other abiotic reactions influencing the fate of environmental contaminants. Experiments will be summarized and placed in context of past and future engineered applications for the control of subsurface contaminants.

  19. Innovative technologies for recycling contaminated concrete and scrap metal

    SciTech Connect

    Bossart, S.J.; Moore, J.

    1993-09-01

    Decontamination and decommissioning of US DOE`s surplus facilities will generate enormous quantities of concrete and scrap metal. A solicitation was issued, seeking innovative technologies for recycling and reusing these materials. Eight proposals were selected for award. If successfully developed, these technologies will enable DOE to clean its facilities by 2019.

  20. METAL CORROSION COUPON CONTAMINATION, CORROSION STUDY DESIGN, AND INTERPRETATION PROBLEMS

    EPA Science Inventory

    As a result of the new Lead and Copper Rule, some water utilities in the United States have begun or will soon begin corrosion demonstration studies. emonstration studies may include pipe rig/loop tests, metal coupon tests, and partial-system tests (fullscale). valuation of corro...

  1. Optimal selection of biochars for remediating metals contaminated mine soils

    EPA Science Inventory

    Approximately 500,000 abandoned mines across the U.S. pose a considerable, pervasive risk to human health and the environment due to possible exposure to the residuals of heavy metal extraction. Historically, a variety of chemical and biological methods have been used to reduce ...

  2. Predicting the toxicity of metal-contaminated field sediments using interstitial concentration of metals and acid-volatile sulfide normalizations

    SciTech Connect

    Hansen, D.J.; Berry, W.J.; Mahony, J.D.

    1996-12-01

    The authors investigated the utility of interstitial water concentrations of metals and simultaneously extracted metal/acid-volatile sulfide (SEM/AVS) ratios to explain the biological availability of sediment-associated divalent metals to benthic organisms exposed in the laboratory to sediments from five saltwater and four freshwater locations in the US, Canada, and China. The amphipod Ampelisca abdita or the polychaete Neanthes arenaceodentata were exposed to 70 sediments from the five saltwater locations, and the amphipod Hyalella azteca or the oligochaete Lumbriculus variegatus were exposed to 55 sediments from four freshwater locations in 10-d lethality tests. Almost complete absence of toxicity in spiked sediments and field sediments where metals were the only known source of contamination and where interstitial water toxic units (IWTUs) were < 0.5 indicates that toxicity associated with sediments having SEM/AVS ratios < 1.0 from two saltwater locations in industrial harbors was not metals-related as these sediments contained <0.5 IWTU. Metals-associated toxicity was absent in 100% of sediments from the remaining three saltwater field locations, where metals were the only known source of contamination and SEM/AVS ratios were {le} 1.0. Two-thirds of 45 sediments from seven saltwater and freshwater field locations having both IWTUs > 0.5 (55%) were used alone. The difference between the molar concentrations of SEM and AVS (SEM-AVS) can provide important insight into the extent of additional available binding capacity, the magnitude by which AVS binding has been exceeded, and, when organism response is considered, the potential magnitude of importance of other metal binding phases. SEM-AVS should be used instead of SEM/AVS ratios as a measure of metals availability. In published experiments with both metal-spiked and field sediments, SEM-AVS and IWTUs accurately identified absence of sediment toxicity and with less accuracy identified the presence of toxicity.

  3. Diversity of arbuscular mycorrhizal fungus populations in heavy-metal-contaminated soils

    SciTech Connect

    Del Val, C.; Barea, J.M.; Azcon-Aguilar, C.

    1999-02-01

    High concentrations of heavy metals have been shown to adversely affect the size, diversity, and activity of microbial populations in soil. The aim of this work was to determine how the diversity of arbuscular mycorrhizal (AM) fungi is affected by the addition of sewage-amended sludge containing heavy metals in a long-term experiment. Due to the reduced number of indigenous AM fungal (AMF) propagules in the experimental soils, several host plants with different life cycles were used to multiply indigenous fungi. Six AMF ecotypes were found in the experimental soils, showing consistent differences with regard to their tolerance to the presence of heavy metals. AMF ecotypes ranged from very sensitive to the presence of metals to relatively tolerant to high rates of heavy metals in soil. Total AMF spore numbers decreased with increasing amounts of heavy metals in the soil. However, species richness and diversity as measured by the Shannon-Wiener index increased in soils receiving intermediate rates of sludge contamination but decreased in soils receiving the highest rate of heavy-metal-contaminated sludge. Relative densities of most AMF species were also significantly influenced by soil treatments. Host plant species exerted a selective influence on AMF population size and diversity. The authors conclude based on the results of this study that size and diversity of AMF populations were modified in metal-polluted soils, even in those with metal concentrations that were below the upper limits accepted by the European Union for agricultural soils.

  4. The occurrence and sources of heavy metal contamination in peri-urban and smelting contaminated sites in Baoji, China.

    PubMed

    Deng, Wenbo; Li, Xuxiang; An, Zhisheng; Yang, Liu

    2016-04-01

    Atmospheric deposition, soil, plant, ore, and coal cinder samples were collected and analyzed to determine heavy metal concentrations in a typical peri-urban industrial area of Baoji. The lead isotope ratio method was employed to trace the source and dispersion of atmospheric heavy metal contamination. Results showed that concentrations of lead, zinc, cadmium, and copper in atmospheric deposition significantly exceed soil background levels and Chinese soil environmental quality standards. The most polluted sites were located in the downwind direction of the smelter, which confirmed this site to be the major pollution source for this area. The other source of heavy metals in this area is a power plant. The investigation into lead isotopes revealed compositions in atmospheric deposition samples were similar to those in ores and coal cinders identifying smelting as the predominant pollution source of lead with the power plant having a minimal effect. Similar isotopic compositions were also found in plants, indicating that the major source of lead in plants was derived from atmospheric deposition, although some evidence was found to suggest uptake from the soil to the roots as an additional contaminant pathway. PMID:27021694

  5. Adverse Events Associated with Metal Contamination of Traditional Chinese Medicines in Korea: A Clinical Review

    PubMed Central

    Kim, Hyunah; Hawes, Emily M.

    2014-01-01

    This study was performed to review studies carried out in Korea reporting toxic reactions to traditional Chinese medicines (TCMs) as a result of heavy metal contamination. PubMed (1966-August 2013) and International Pharmaceutical Abstracts (1965-August 2013) were searched using the medical subject heading terms of "Medicine, Chinese Traditional," "Medicine, Korean Traditional," "Medicine, Traditional," "Metals, Heavy," and "Drug Contamination". For Korean literature, Korea Med (http://www.koreamed.org), the Korean Medical Database (http://kmbase.medric.or.kr), National Discovery for Science Leaders (www.ndsl.kr), Research Information Sharing Service (http://www.riss.kr), and Google Scholar were searched using the terms "Chinese medicine," "Korean medicine," "herbal medicine," and "metallic contamination" in Korean. Bibliographies of case reports and case series, identified using secondary resources, were also utilized. Only literature describing cases or studies performed in Korea were included. Case reports identified clear issues with heavy metal, particularly lead, contamination of TCMs utilized in Korea. No international standardization guidelines for processing, manufacturing and marketing of herbal products exist. Unacceptably high levels of toxic metals can be present in TCM preparations. Health care providers and patients should be educated on the potential risks associated with TCMs. International advocacy for stricter standardization procedures for production of TCMs is warranted. PMID:25048473

  6. Spatial distribution of heavy metal contamination in soils near a primitive e-waste recycling site.

    PubMed

    Quan, Sheng-Xiang; Yan, Bo; Yang, Fan; Li, Ning; Xiao, Xian-Ming; Fu, Jia-Mo

    2015-01-01

    The total concentrations of 12 heavy metals in surface soils (SS, 0-20 cm), middle soils (MS, 30-50 cm) and deep soils (DS, 60-80 cm) from an acid-leaching area, a deserted paddy field and a deserted area of Guiyu were measured. The results showed that the acid-leaching area was heavily contaminated with heavy metals, especially in SS. The mean concentrations of Ni, Cu, Zn, Cd, Sn, Sb and Pb in SS from the acid-leaching area were 278.4, 684.1, 572.8, 1.36, 3,472, 1,706 and 222.8 mg/kg, respectively. Heavy metal pollution in the deserted paddy field was mainly concentrated in SS and MS. The average values of Sb in SS and MS from the deserted paddy field were 16.3 and 20.2 mg/kg, respectively. However, heavy metal contamination of the deserted area was principally found in the DS. Extremely high concentrations of heavy metals were also observed at some special research sites, further confirming that the level of heavy metal pollution was very serious. The geoaccumulation index (Igeo) values revealed that the acid-leaching area was severely polluted with heavy metals in the order of Sb > Sn > Cu > Cd > Ni > Zn > Pb, while deserted paddy field was contaminated predominately by metals in the order of Sb > Sn > Cu. It was obvious that the concentrations of some uncommon contaminants, such as Sb and Sn, were higher than principal contaminants, such as Ni, Cu, Zn and Pb, suggesting that particular attention should be directed to Sn and Sb contamination in the future research of heavy metals in soils from e-waste-processing areas. Correlation analysis suggested that Li and Be in soils from the acid-leaching area and its surrounding environment might have originated from other industrial activities and from batteries, whereas Ni, Cu, Zn, Cd, Pb, Sn and Sb contamination was most likely caused by uncontrolled electronic waste (e-waste) processing. These results indicate the significant need for optimisation of e-waste-dismantling technologies and remediation of polluted soil

  7. Heavy metal contamination and its indexing approach for groundwater of Goa mining region, India

    NASA Astrophysics Data System (ADS)

    Singh, Gurdeep; Kamal, Rakesh Kant

    2016-06-01

    The objective of the study is to reveal the seasonal variations in the groundwater quality with respect to heavy metal contamination. To get the extent of the heavy metals contamination, groundwater samples were collected from 45 different locations in and around Goa mining area during the monsoon and post-monsoon seasons. The concentration of heavy metals, such as lead, copper, manganese, zinc, cadmium, iron, and chromium, were determined using atomic absorption spectrophotometer. Most of the samples were found within limit except for Fe content during the monsoon season at two sampling locations which is above desirable limit, i.e., 300 µg/L as per Indian drinking water standard. The data generated were used to calculate the heavy metal pollution index (HPI) for groundwater. The mean values of HPI were 1.5 in the monsoon season and 2.1 in the post-monsoon season, and these values are well below the critical index limit of 100.

  8. Bioremediation of heavy metals in liquid media through fungi isolated from contaminated sources.

    PubMed

    Joshi, P K; Swarup, Anand; Maheshwari, Sonu; Kumar, Raman; Singh, Namita

    2011-10-01

    Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain enormous amount of heavy metals. Microorganisms including fungi have been reported to exclude heavy metals from wastewater through bioaccumulation and biosorption at low cost and in eco-friendly way. An attempt was, therefore, made to isolate fungi from sites contaminated with heavy metals for higher tolerance and removal of heavy metals from wastewater. Seventy-six fungal isolates tolerant to heavy metals like Pb, Cd, Cr and Ni were isolated from sewage, sludge and industrial effluents containing heavy metals. Four fungi (Phanerochaete chrysosporium, Aspegillus awamori, Aspergillus flavus, Trichoderma viride) also were included in this study. The majority of the fungal isolates were able to tolerate up to 400 ppm concentration of Pb, Cd, Cr and Ni. The most heavy metal tolerant fungi were studied for removal of heavy metals from liquid media at 50 ppm concentration. Results indicated removal of substantial amount of heavy metals by some of the fungi. With respect to Pb, Cd, Cr and Ni, maximum uptake of 59.67, 16.25, 0.55, and 0.55 mg/g was observed by fungi Pb3 (Aspergillus terreus), Trichoderma viride, Cr8 (Trichoderma longibrachiatum), and isolate Ni27 (A. niger) respectively. This indicated the potential of these fungi as biosorbent for removal of heavy metals from wastewater and industrial effluents containing higher concentration of heavy metals. PMID:23024411

  9. The use of dialdehyde starch derivatives in the phytoremediation of soils contaminated with heavy metals.

    PubMed

    Antonkiewicz, Jacek; Para, Andrzej

    2016-01-01

    Products of the reaction between dialdehyde starch and Y-NH2 compounds (e.g. semicarbazide or hydrazine) are effective ligands for metal ions. The usefulness of these derivatives was tested in the experiment, both in terms of the immobilization of heavy metal ions in soil and the potential application in phytoextraction processes. The experimental model comprised maize and the ions of such metals as: Zn(II), Pb(II), Cu(II), Cd(II), and Ni(II). The amount of maize yield, as well as heavy metal content and uptake by the aboveground parts and roots of maize, were studied during a three-year pot experiment. The results of the study indicate the significant impact of heavy metals on reduced yield and increased heavy metal content in maize. Soil-applied dialdehyde starch derivatives resulted in lower yields, particularly disemicarbazone (DASS), but in heavy metal-contaminated soils they largely limited the negative impact of these metals both on yielding and heavy metal content in plants, particularly dihydrazone (DASH). It was demonstrated that the application of dihydrazone (DASH) to a soil polluted with heavy metals boosted the uptake of Zn, Pb, Cu, and Cd from the soil, hence there is a possibility to use this compound in the phytoextraction of these metals from the soil. Decreased Ni uptake was also determined, hence the possibility of using this compound in the immobilization of this metal. The study showed that dialdehyde starch disemicarbazone was ineffective in the discussed processes. PMID:26280197

  10. Utilization of the seagrass Posidonia oceanica to evaluate the spatial dispersion of metal contamination.

    PubMed

    Lafabrie, C; Pergent, G; Pergent-Martini, C

    2009-03-15

    Metal concentrations have been measured in blades of the endemic Mediterranean seagrass Posidonia oceanica, along transects from three different contaminant point sources (the former asbestos mine of Canari - Corsica, France; the chemical plant of Solvay/Rosignano - Livorno, Italy; and the industrial harbour of Porto-Torres - Sardinia, Italy). The aim of this study was to evaluate the spatial extent of the impact of these sources in terms of metal contamination. The results showed that metal contamination from the former mine of Canari (cobalt - Co, chromium - Cr and nickel - Ni) extends at least 5 km to the north and south. The impact of this mine, which closed in 1965, seems to be lingering still. Mercury (Hg) contamination in the Livorno location was difficult to evaluate due to the presence of others potential sources of mercury in the area (e.g. industrialized city of Livorno, natural cinnabar deposits, intense tectonic activity of the area). At any rate, mercury concentration decreased strongly with distance from the plant. Lead (Pb) contamination at the Porto-Torres harbour was very low and disappeared with distance from the harbour. However, as the Porto-Torres harbour does not appear as a substantial point source of Pb contamination and because of the ubiquitous characteristic of the Pb element, it is difficult to draw any general conclusions concerning this element. The results presented in this study demonstrated the usefulness of the seagrass P. oceanica as a tool for the evaluation of the spatial extent of metal contaminations from point sources and could, therefore, contribute to on-going efforts to manage coastal environments. PMID:19081604

  11. Fingerprinting sedimentary and soil units by their natural metal contents: a new approach to assess metal contamination.

    PubMed

    Amorosi, Alessandro; Guermandi, Marina; Marchi, Nazaria; Sammartino, Irene

    2014-12-01

    One of the major issues when assessing soil contamination by inorganic substances is reliable determination of natural metal concentrations. Through integrated sedimentological, pedological and geochemical analyses of 1414 (topsoil/subsoil) samples from 707 sampling stations in the southern Po Plain (Italy), we document that the natural distribution of five potentially toxic metals (Cr, Ni, Cu, Zn and Pb) can be spatially predicted as a function of three major factors: source-rock composition, grain size variability and degree of soil weathering. Thirteen genetic and functional soil units (GFUs), each reflecting a unique combination of these three variables, are fingerprinted by distinctive geochemical signatures. Where sediment is supplied by ultramafic (ophiolite-rich) sources, the natural contents of Cr and Ni in soils almost invariably exceed the Italian threshold limits designated for contaminated lands (150 mg/kg and 120 mg/kg, respectively), with median values around twice the maximum permissible levels (345 mg/kg for Cr and 207 mg/kg for Ni in GFU B5). The original provenance signal is commonly confounded by soil texture, with general tendency toward higher metal concentrations in the finest-grained fractions. Once reliable natural metal concentrations in soils are established, the anthropogenic contribution can be promptly assessed by calculating metal enrichments in topsoil samples. The use of combined sedimentological and pedological criteria to fingerprint GFU geochemical composition is presented here as a new approach to enhance predictability of natural metal contents, with obvious positive feedbacks for legislative purposes and environmental protection. Particularly, natural metal concentrations inferred directly from a new type of pedogeochemical map, built according to the international guideline ISO 19258, are proposed as an efficient alternative to the pre-determined threshold values for soil contamination commonly established by the national

  12. Note: Contamination-free loading of lithium metal into a nozzle source.

    PubMed

    Huang, Chuanfu; Kresin, Vitaly V

    2016-06-01

    This note describes a system for transferring a load of high purity lithium metal into a molecular or cluster beam source. A hot loading vessel is thoroughly baked out while empty and overpressured with argon. A clean Li rod is then dropped in through a long narrow tube. The thoroughly degassed interior of the vessel and the rapid melting of the inserted rod facilitate contamination-free transfer of the highly reactive liquid metal into the source oven. PMID:27370506

  13. Note: Contamination-free loading of lithium metal into a nozzle source

    NASA Astrophysics Data System (ADS)

    Huang, Chuanfu; Kresin, Vitaly V.

    2016-06-01

    This note describes a system for transferring a load of high purity lithium metal into a molecular or cluster beam source. A hot loading vessel is thoroughly baked out while empty and overpressured with argon. A clean Li rod is then dropped in through a long narrow tube. The thoroughly degassed interior of the vessel and the rapid melting of the inserted rod facilitate contamination-free transfer of the highly reactive liquid metal into the source oven.

  14. The distinction of pristine from meteorite-contaminated highlands rocks using metal compositions

    NASA Technical Reports Server (NTRS)

    Ryder, G.; Norman, M. D.; Score, R. A.

    1980-01-01

    Pristine highlands rocks, i.e., those which have retained the chemical characteristics they acquired from igneous processes, contain metal grains whose Ni and Co contents are distinct from those in most polymict, meteorite-contaminated rocks. The difference is mainly a result of the bulk Ni/Co ratios of pristine rocks being much lower than those of chondritic meteorites. The compositions of metal grains thus provide a rapid and effective criterion for the recognition of pristine highlands samples.

  15. Remediation of Deep Vadose Zone Radionuclide and Metal Contamination: Status and Issues

    SciTech Connect

    Dresel, P. Evan; Truex, Michael J.; Cantrell, Keri

    2008-12-30

    This report documents the results of a PNNL literature review to report on the state of maturity of deep vadose zone remediation technologies for metal contaminants including some radionuclides. Its recommendations feed into decisionmakers need for scientific information and cost-effective in situ remediation technlogies needed under DOE's Environmental Management initiative Enhanced Remediation Methods: Scientific & Technical Basis for In Stu Treatment Systems for Metals and Radionuclides.

  16. Constraints in cropping heavy-metal contaminated fluvial sediments.

    PubMed

    Smilde, K W; van Driel, W; van Luit, B

    1982-11-01

    Growth and heavy-metal uptake of various food crops and grass cultivated on harbour dredge spoils were studied, and health aspects in consuming the marketable products were discussed. Vegetables (potato, carrot, radish, endive, lettuce) and grass (English ryegrass) performed well on dredge spoils, but small grains (wheat, barley) were affected by manganese deficiency. As compared with crops grown on uncontaminated reference soils, there was a net accumulation of As and heavy metals, especially so Cd, Zn and Cu, and a reduced uptake of Mn. Mainly because of the elevated Cd concentrations of the edible parts, exceeding the guideline of 0.1 mg/kg in fresh matter, the harbour dredge spoils investigated are considered unfit for the production of food crops, but may be used as grassland for dairy cattle. Highest Cd concentrations were attained in leafy vegetables and wheat (grain) and lowest in potato (tuber). PMID:7156971

  17. Metal corrosion coupon contamination, corrosion study design, and interpretation problems

    SciTech Connect

    Lytle, D.A.; Schock, M.R.; Tackett, S.

    1992-01-01

    As a result of the new Lead and Copper Rule, some water utilities in the United States have begun or will soon begin corrosion demonstration studies. Demonstration studies may include pipe rig/loop tests, metal coupon tests, and partial-system tests (full-scale). Evaluation of corrosion control treatment through testing may be accomplished by weight loss measurement, metal leaching, corrosion rate, or coupon surface inspection techniques. The purpose of the paper is to (1) briefly introduce 2 corrosion control studies being conducted at the EPA Research Facility, (2) discuss design and operational problems and considerations associated with each of the studies, and (3) present solutions to the problems. The experiences related to the paper may provide useful and time-saving insights into the design, operation, and interpretation of corrosion control studies to water utilities and suppliers.

  18. Large-area experiment on uptake of metals by twelve plants growing in soils contaminated with multiple metals.

    PubMed

    Lai, Hung-Yu; Juang, Kai-Wei; Chen, Zueng-Sang

    2010-01-01

    A site in central Taiwan with an area of 1.3 ha and contaminated with Cr, Cu, Ni, and Zn was selected to examine the feasibility of phytoextraction. Based on the results of a preexperiment at this site, a total of approximately 20,000 plants of 12 species were selected from plants of 33 tested species to be used in a large-area phytoextraction experiment at this site. A comparison with the initial metal concentration of 12 plant species before planting demonstrated that most species accumulated significant amounts of Cr, Cu, Ni, and Zn in their shoots after growing in this contaminated site for 31 d. Among the 12 plant species, the following accumulated higher concentrations of metals in their shoots; Garden canna and Garden verbena (45-60 mg Cr kg(-1)), Chinese ixora and Kalanchoe (30 mg Cu kg(-1)), Rainbow pink and Sunflower (30 mg Ni kg(-1)), French marigold and Sunflower (300-470 mg Zn kg(-1)). The roots of the plants of most of the 12 plant species can accumulate higher concentrations of metals than the shoots and extending the growth period promotes accumulation in the shoots. Large-area experiments demonstrated that phytoextraction is a feasible method to enable metal-contaminated soil in central Taiwan to be reused. PMID:21166348

  19. Accumulation of heavy metals from contaminated soil to plants and evaluation of soil remediation by vermiculite.

    PubMed

    Malandrino, Mery; Abollino, Ornella; Buoso, Sandro; Giacomino, Agnese; La Gioia, Carmela; Mentasti, Edoardo

    2011-01-01

    We evaluated the distribution of 15 metal ions, namely Al, Cd, Cu, Cr, Fe, La, Mn, Ni, Pb, Sc, Ti, V, Y, Zn and Zr, in the soil of a contaminated site in Piedmont (Italy). This area was found to be heavily contaminated with Cu, Cr and Ni. The availability of these metal ions was studied using Tessier's sequential extraction procedure: the fraction of mobile species, which potentially is the most harmful for the environment, was much higher than that normally present in unpolluted soils. This soil was hence used to evaluate the effectiveness of treatment with vermiculite to reduce the availability of the pollutants to two plants, Lactuca sativa and Spinacia oleracea, by pot experiments. The results indicated that the addition of vermiculite significantly reduces the uptake of metal pollutants by plants, confirming the possibility of using this clay in amendment treatments of metal-contaminated soils. The effect of plant growth on metal fractionation in soils was investigated. Finally, the sum of the metal percentages extracted into the first two fractions of Tessier's protocol was found to be suitable in predicting the phytoavailability of most of the pollutants present in the investigated soil. PMID:21055788

  20. [Using kenaf (Hibiscus cannabinus) to reclaim multi-metal contaminated acidic soil].

    PubMed

    Yang, Yu-Xi; Lu, Huan-Liang; Zhan, Shu-Shun; Deng, Teng-hao-bo; Lin, Qing-Qi; Wang, Shi-Zhong; Yang, Xiu-Hong; Qiu, Rong-Liang

    2013-03-01

    A five-year field trial was conducted at the surrounding area of Dabao Mountain Mine to explore the feasibility and availability of using kenaf (Hibiscus cannabinus) , a fiber crop with strong heavy metals tolerance and potential economic value, to reclaim the multi-metal contaminated acidic farmland soil. Different amendments were applied prior to the kenaf planting to evaluate their effects on the soil properties and kenaf growth. After the amendments application, the kenaf could grow well on the heavy metals contaminated soil with the Pb, Zn, Cu, Cd, and As concentrations being 1600, 440, 640, 7. 6, and 850 mg . kg-1, respectively. Among the amendments, dolomite and fly ash had better effects than limestone and organic fertilizer. With the application of dolomite and fly ash, the aboveground dry mass production of kenaf reached 14-15 t . hm-2, which was similar to that on normal soils, and the heavy metal concentrations in the bast fiber and stem of kenaf decreased significantly, as compared with the control. The mass of the bast fiber accounted for 32% -38% of the shoot production, and the extractable heavy metal concentrations in the bast fiber could meet the standard of 'technical specifications of ecological textiles' in China, suggesting that the bast fiber had potential economic value. It was suggested that planting kenaf combining with dolomite/fly ash application could be an effective measure to reclaim the multi-metal contaminated acidic farmland soil. PMID:23755502

  1. Bioremediation of contaminated marine sediments can enhance metal mobility due to changes of bacterial diversity.

    PubMed

    Fonti, Viviana; Beolchini, Francesca; Rocchetti, Laura; Dell'Anno, Antonio

    2015-01-01

    Bioremediation strategies applied to contaminated marine sediments can induce important changes in the mobility and bioavailability of metals with potential detrimental consequences on ecosystem health. In this study we investigated changes of bacterial abundance and diversity (by a combination of molecular fingerprinting and next generation sequencing analyses) during biostimulation experiments carried out on anoxic marine sediments characterized by high metal content. We provide evidence that the addition of organic (lactose and/or acetate) and/or inorganic compounds to contaminated sediments determines a significant increase of bacterial growth coupled with changes in bacterial diversity and assemblage composition. Experimental systems supplied only with organic substrates were characterized by an increase of the relative importance of sulfate reducing bacteria belonging to the families Desulfobacteraceae and Desulfobulbaceae with a concomitant decrease of taxa affiliated with Flavobacteriaceae. An opposite effect was observed in the experimental treatments supplied also with inorganic nutrients. The increase of bacterial metabolism coupled with the increase of bacterial taxa affiliated with Flavobacteriaceae were reflected in a significant decrease of Cd and Zn associated with sedimentary organic matter and Pb and As associated with the residual fraction of the sediment. However, independently from the experimental conditions investigated no dissolution of metals occurred, suggesting a role of bacterial assemblages in controlling metal solubilization processes. Overall results of this study have allowed to identify key biogeochemical interactions influencing the metal behavior and provide new insights for a better understanding of the potential consequences of bio-treatments on the metal fate in contaminated marine sediments. PMID:25462769

  2. Biological leaching of heavy metals from a contaminated soil by Aspergillus niger.

    PubMed

    Ren, Wan-Xia; Li, Pei-Jun; Geng, Yong; Li, Xiao-Jun

    2009-08-15

    Bioleaching of heavy metals from a contaminated soil in an industrial area using metabolites, mainly weak organic acids, produced by a fungus Aspergillus niger was investigated. Batch experiments were performed to compare the leaching efficiencies of one-step and two-step processes and to determine the transformation of heavy metal chemical forms during the bioleaching process. After the one or two-step processes, the metal removals were compared using analysis of variance (ANOVA) and least-significance difference (LSD). A. niger exhibits a good potential in generating a variety of organic acids effective for metal solubilisation. Results showed that after the one-step process, maximum removals of 56%, 100%, 30% and 19% were achieved for copper, cadmium, lead and zinc, respectively. After the two-step process, highest removals of 97.5% Cu, 88.2% Cd, 26% Pb, and 14.5% Zn were obtained. Results of sequential extraction showed that organic acids produced by A. niger were effective in removing the exchangeable, carbonate, and Fe/Mn oxide fractions of Cu, Cd, Pb and Zn; and after both processes the metals remaining in the soil were mainly bound in stable fractions. Such a treatment procedure indicated that leaching of heavy metals from contaminated soil using A. niger has the potential for use in remediation of contaminated soils. PMID:19232463

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

    PubMed

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

    2016-03-15

    Sediments play an important role on the quality of aquatic ecosystems, notably in the reservoir areas where they can either be a sink or a source of contaminants, depending on the management and hydrological conditions. The physicochemical properties of 25 surface sediments samples of a reservoir catchment (Vaussaire, Cantal, France) were studied. Results show a strong influence of dam presence, notably on the grain size and organic matter (OM) contents. The concentrations of trace metals and metalloids (As, Cd, Cr, Cu, Ni, Pb and Zn) were also measured and compared with worldwide reservoir concentrations and international sediment quality guideline levels in order to assess the intensity of the metallic contamination. Cr and Ni are the trace elements presenting the significantly highest values at the catchment scale. Enrichment Factors (EF), calculated using both local and national backgrounds, show that metals have mainly a natural origin, explaining especially the Cr and Ni values, linked with the composition of parental rocks. Unexpectedly, all the observed metal concentrations are lower in the reservoir than upstream and downstream, which might be related to the high fresh OM inputs in the reservoir, diluting the global metallic contamination. Multivariate statistical analyses, carried out in order to identify the relationship between the studied metals and sediment characteristics, tend to support this hypothesis, confirming the unusually low influence of such poorly-degraded OM on trace element accumulation in the reservoir. PMID:26789366

  4. Assessing the risk of metal mixtures in contaminated sediments on Chironomus riparius based on cytosolic accumulation.

    PubMed

    Péry, Alexandre R R; Geffard, Alain; Conrad, Arnaud; Mons, Raphaël; Garric, Jeanne

    2008-11-01

    Sediments usually contain mixtures of trace metals introduced via natural geochemical processes and anthropogenic activities. Kinetics and effects of these metals are strongly dependent both on the composition of the mixture and on the physico-chemical characteristics of the sediment. Relating effects to metal concentration may consequently be advised. However, total accumulation may be a poor predictor of metal toxicity for Chironomus riparius exposed to contaminated field sediments. As an alternative, we proposed to relate effects on Chironomus growth with cytosolic metal accumulation, measured in larvae after a short exposure period. Dose-response relationships were derived for zinc, copper, and cadmium through single-metal exposure data analysed with toxicokinetics and toxicodynamics models. They permitted, on the basis of cytosolic accumulation measures, to predict successfully the effects of mixtures of cadmium, zinc, and copper on the growth of larvae exposed to spiked sediments, as well as to field sediments in which zinc and copper were assumed to be predominant. PMID:18514899

  5. Biosorption of metal contaminants using immobilized biomass: A laboratory study. Rept. of Investigations/1991

    SciTech Connect

    Jeffers, T.H.; Ferguson, C.R.; Bennett, P.G.

    1991-01-01

    The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials for removing metal contaminants from waste waters. The beads, designated as BIO-FIX beads, are prepared by blending biomass, such as sphagnum peat moss or algae, into a polymer solution and spraying the mixture into water. Laboratory studies were conducted to determine bead sorption and elution characteristics. Batch and continuous tests demonstrated that BIO-FIX beads sorbed arsenic, cadmium, lead, and other toxic metals from acid mine drainage waters collected from several sites. Selectivity for heavy and toxic metal ions over calcium and magnesium was demonstrated. The beads exhibited excellent metal sorption and handling characteristics in stirred tanks, column contactors, and a low-maintenance passive system. The sorption process was reversible, and metal ions were eluted from the beads using dilute mineral acids. Cyclic tests indicated that the beads continued to extract metal ions after repeated loading-elution cycles.

  6. Assessment of heavy metal contamination in soils around Manali industrial area, Chennai, Southern India

    NASA Astrophysics Data System (ADS)

    Krishna, A. K.; Govil, P. K.

    2008-06-01

    The concentrations of heavy metals (As, Ba, Co, Cr, Cu, Ni, Mo, Pb, Sr, V and Zn) were studied in soils to understand metal contamination due to industrialization and urbanization around Manali industrial area in Chennai, Southern India. This area is affected by the industrial activity and saturated by industries like petrochemicals, refineries, and fertilizers generating hazardous wastes. The contamination of the soils was assessed on the basis of geoaccumulation index, enrichment factor (EF), contamination factor and degree of contamination. Soil samples were collected from the industrial area of Manali from the top 10-cm-layer of the soil. Soil samples were analyzed for heavy metals by using Philips MagiX PRO-2440 Wavelength dispersive X-ray fluorescence spectrometry. The data revealed elevated concentrations of Chromium (149.8-418.0 mg/kg), Copper (22.4-372.0 mg/kg), Nickel (11.8-78.8 mg/kg), Zinc (63.5-213.6 mg/kg) and Molybdenum (2.3-15.3 mg/kg). The concentrations of other elements were similar to the levels in the earth’s crust or pointed to metal depletion in the soil (EF < 1). The high-EFs for some heavy metals obtained in the soil samples show that there is a considerable heavy metal pollution, which could be correlated with the industries in the area. Contamination sites pose significant environmental hazards for terrestrial and aquatic ecosystems. They are important sources of pollution and may result in ecotoxicological effects on terrestrial, groundwater and aquatic ecosystems. In this perspective there is need for a safe dumping of waste disposal in order to minimize environmental pollution.

  7. Soil contamination of heavy metals in the Katedan Industrial Development Area, Hyderabad, India.

    PubMed

    Govil, P K; Sorlie, J E; Murthy, N N; Sujatha, D; Reddy, G L N; Rudolph-Lund, Kim; Krishna, A K; Rama Mohan, K

    2008-05-01

    Studies on quantitative soil contamination due to heavy metals were carried out in Katedan Industrial Development Area (KIDA), south of Hyderabad, Andhra Pradesh, India under the Indo-Norwegian Institutional Cooperation Programme. The study area falls under a semi-arid type of climate and consists of granites and pegmatite of igneous origin belonging to the Archaean age. There are about 300 industries dealing with dyeing, edible oil production, battery manufacturing, metal plating, chemicals, etc. Most of the industries discharge their untreated effluents either on open land or into ditches. Solid waste from industries is randomly dumped along roads and open grounds. Soil samples were collected throughout the industrial area and from downstream residential areas and were analysed by X-ray Fluorescence Spectrometer for fourteen trace metals and ten major oxides. The analytical data shows very high concentrations of lead, chromium, nickel, zinc, arsenic and cadmium through out the industrial area. The random dumping of hazardous waste in the industrial area could be the main cause of the soil contamination spreading by rainwater and wind. In the residential areas the local dumping is expected to be the main source as it is difficult to foresee that rain and wind can transport the contaminants from the industrial area. If emission to air by the smokestacks is significant, this may contribute to considerable spreading of contaminants like As, Cd and Pb throughout the area. A comparison of the results with the Canadian Soil Quality Guidelines (SQGL) show that most of the industrial area is heavily contaminated by As, Pb and Zn and local areas by Cr, Cu and Ni. The residential area is also contaminated by As and some small areas by Cr, Cu, Pb and Zn. The Cd contamination is detected over large area but it is not exceeding the SQGL value. Natural background values of As and Cr exceed the SQGL values and contribute significantly to the contamination in the residential area

  8. Metal contaminated biochar and wood ash negatively affect plant growth and soil quality after land application.

    PubMed

    Jones, D L; Quilliam, R S

    2014-07-15

    Pyrolysis or combustion of waste wood can provide a renewable source of energy and produce byproducts which can be recycled back to land. To be sustainable requires that these byproducts pose minimal threat to the environment or human health. Frequently, reclaimed waste wood is contaminated by preservative-treated timber containing high levels of heavy metals. We investigated the effect of feedstock contamination from copper-preservative treated wood on the behaviour of pyrolysis-derived biochar and combustion-derived ash in plant-soil systems. Biochar and wood ash were applied to soil at typical agronomic rates. The presence of preservative treated timber in the feedstock increased available soil Cu; however, critical Cu guidance limits were only exceeded at high rates of feedstock contamination. Negative effects on plant growth and soil quality were only seen at high levels of biochar contamination (>50% derived from preservative-treated wood). Negative effects of wood ash contamination were apparent at lower levels of contamination (>10% derived from preservative treated wood). Complete removal of preservative treated timber from wood recycling facilities is notoriously difficult and low levels of contamination are commonplace. We conclude that low levels of contamination from Cu-treated wood should pose minimal environmental risk to biochar and ash destined for land application. PMID:24915641

  9. Contamination from an affluent of Furnas reservoir by trace metals.

    PubMed

    Cavalcanti, P P; Rodrigues, L C A; Beijo, L A; Barbosa, S; Xavier, T T; Magalhães, F

    2014-11-01

    This study aims to determine concentrations and characterize trace metals distribution in an affluent of Furnas reservoir, Alfenas-MG. Water and sediment samples were taken monthly, 2010/10-2011/07 in five sites of Córrego do Pântano for subsequent determination of Pb, Cd and Zn levels by chemical analysis. The stream studied is in disagreement with Brazilian legislation for Class II water bodies (CONAMA 357). The highlights are the unsuitable concentrations of Pb for human consumption, according to Ministry of Health 2914 decree, providing risk for population. PMID:25627598

  10. Emerging Technology Summary. ACID EXTRACTION TREATMENT SYSTEM FOR TREATMENT OF METAL CONTAMINATED SOILS

    EPA Science Inventory

    The Acid Extraction Treatment System (AETS) is intended to reduce the concentrations and/or teachability of heavy metals in contaminated soils so the soil can be returned to the site from which it originated. The objective of the project was to determine the effectiveness and com...

  11. Mobility of heavy metals from tailings to stream waters in a mining activity contaminated site.

    PubMed

    Concas, A; Ardau, C; Cristini, A; Zuddas, P; Cao, G

    2006-04-01

    In this paper the results of a recent characterization of Rio Piscinas (SW of Sardinia, Italy) hydrological basin are reported. In such area (about 50 km2), previous mining activities caused a serious heavy metal contamination of surface waters, groundwater, soils and biota. Acid mine drainage phenomena were observed in the area. The main sources of contamination are the tailings stored in mine tunnels and abandoned along fluvial banks. A methodological approach was adopted in order to identify relations between tailings and water contamination. Representative samples of tailings and stream sediments samples were collected. XRD analyses were performed for mineralogical characterization, while acid digestion was carried out for determining metal contents. Batch sequential leaching tests were performed in order to assess metal mobility. Also groundwater and stream water were sampled in specific locations and suitably characterized. All information collected allowed the understanding of the effect of tailings on water contamination, thus contributing to the qualitative prediction of pollution evolution on the basis of metal mobility. Finally, a potential remediation strategy of stream water is proposed. PMID:16216301

  12. Changes in the structure and function of soil ecosystems in soils contaminated with heavy metals

    SciTech Connect

    Kuperman, R.; Parmelee, R.; Carreiro, M. ||

    1995-06-01

    The structure and function of soil communities in an area with a wide range of concentrations of heavy metals was studied in portions of the U.S. Army`s Aberdeen Proving Ground, Maryland. The study included survey of soil macro- and microinvertebrate communities, soil microorganisms, enzyme activities and the rates of nutrient dynamics in soil. Soil macroinvertebrate communities showed significant reductions in the abundance of several taxonomic and functional groups in contaminated areas. The total numbers of nematodes and numbers of fungivore, bacterivore and omnivore-predator nematodes were lower in the more contaminated areas. The numbers of active bacteria and fungi were lower in areas of soil contamination. Significant reduction in the activities of all enzymes closely paralleled the increase in heavy metal concentrations. Ten-to-fifty fold reductions in enzyme activities were observed as heavy metal concentrations increased. These results suggest that soil contamination with heavy metals may have detrimental effects on soil biota and the rates of organic matter degradation and subsequent release of nutrients to aboveground communities in the area.

  13. Changes in the structure and function of soil ecosystems in soils contaminated with heavy metals

    SciTech Connect

    Kuperman, R.; Parmelee, R.; Carreiro, M. ||

    1995-09-01

    The structure and function of soil communities in an area with a wide range of concentrations of heavy metals was studied in portions of the U.S. Army`s Aberdeen Proving Ground, Maryland. The study included survey of soil macro- and microinvertebrate communities, soil microorganisms, enzyme activities and the rates of nutrient dynamics in soil. Soil macroinvertebrate communities showed significant reductions in the adundance of several taxonomic and functional groups in contaminated areas. The total numbers of nematodes and numbers of fungivore, bacterivore and omnivore-predator nematodes were lower in the more contaminated areas. The numbers of active bacteria and fungi were lower in areas of soil contamination. Significant reduction in the activities of all enzymes closely paralleled the increase in heavy metal concentrations. Ten-to-fifty fold reductions in enzyme activities were observed as heavy metal concentrations increased. These results suggest that soil contamination with heavy metals may have detrimental effects on soil biota and the rates of organic matter degradation and subsequent release of nutrients to aboveground communities in the area.

  14. Preliminary Results: Release Of Metals From Acid-Mine Drainage Contaminated Streambed Sediments Under Anaerobic Conditions

    EPA Science Inventory

    Many miles of streams in the western U.S. are contaminated with acid-mine drainage (AMD) from abandoned metal mines. Treatment of these streams may include removal of the existing sediments, with subsequent burial (e.g., in a repository). Burial of previously aerobic sediments ma...

  15. Source identification of heavy metal contamination using metal association and Pb isotopes in Ulsan Bay sediments, East Sea, Korea.

    PubMed

    Chae, Jung Sun; Choi, Man Sik; Song, Yun Ho; Um, In Kwon; Kim, Jae Gon

    2014-11-15

    To determine the characteristics of metal pollution sources in Ulsan Bay, East Sea, 39 surface and nine core sediments were collected within the bay and offshore area, and analyzed for metals and stable lead (Pb) isotopes. Most surface sediments (>95% from 48 sites) had high copper (Cu), zinc (Zn), cadmium (Cd), and Pb concentrations that were as much as 1.3 times higher than background values. The primary source of metal contamination came from activities related to nonferrous metal refineries near Onsan Harbor, and the next largest source was from shipbuilding companies located at the mouth of the Taehwa River. Three different anthropogenic sources and background sediments could be identified as end-members using Pb isotopes. Isotopic ratios for the anthropogenic Pb revealed that the sources were imported ores from Australia, Peru, and the United States. In addition, Pb isotopes of anthropogenic Pb discharged from Ulsan Bay toward offshore could be determined. PMID:25148756

  16. Tolerance to Cadmium of Agave lechuguilla (Agavaceae) Seeds and Seedlings from Sites Contaminated with Heavy Metals

    PubMed Central

    Méndez-Hurtado, Alejandra; Rangel-Méndez, René; Flores, Joel

    2013-01-01

    We investigated if seeds of Agave lechuguilla from contaminated sites with heavy metals were more tolerant to Cd ions than seeds from noncontaminated sites. Seeds from a highly contaminated site (Villa de la Paz) and from a noncontaminated site (Villa de Zaragoza) were evaluated. We tested the effect of Cd concentrations on several ecophysiological, morphological, genetical, and anatomical responses. Seed viability, seed germination, seedling biomass, and radicle length were higher for the non-polluted site than for the contaminated one. The leaves of seedlings from the contaminated place had more cadmium and showed peaks attributed to chemical functional groups such as amines, amides, carboxyl, and alkenes that tended to disappear due to increasing the concentration of cadmium than those from Villa de Zaragoza. Malformed cells in the parenchyma surrounding the vascular bundles were found in seedlings grown with Cd from both sites. The leaves from the contaminated place showed a higher metallothioneins expression in seedlings from the control group than that of seedlings at different Cd concentrations. Most of our results fitted into the hypothesis that plants from metal-contaminated places do not tolerate more pollution, because of the accumulative effect that cadmium might have on them. PMID:24453802

  17. Passive sampling methods for contaminated sediments: State of the science for metals

    PubMed Central

    Peijnenburg, Willie JGM; Teasdale, Peter R; Reible, Danny; Mondon, Julie; Bennett, William W; Campbell, Peter GC

    2014-01-01

    “Dissolved” concentrations of contaminants in sediment porewater (Cfree) provide a more relevant exposure metric for risk assessment than do total concentrations. Passive sampling methods (PSMs) for estimating Cfree offer the potential for cost-efficient and accurate in situ characterization of Cfree for inorganic sediment contaminants. In contrast to the PSMs validated and applied for organic contaminants, the various passive sampling devices developed for metals, metalloids, and some nonmetals (collectively termed “metals”) have been exploited to a limited extent, despite recognized advantages that include low detection limits, detection of time-averaged trends, high spatial resolution, information about dissolved metal speciation, and the ability to capture episodic events and cyclic changes that may be missed by occasional grab sampling. We summarize the PSM approaches for assessing metal toxicity to, and bioaccumulation by, sediment-dwelling biota, including the recognized advantages and limitations of each approach, the need for standardization, and further work needed to facilitate broader acceptance and application of PSM-derived information by decision makers. Integr Environ Assess Manag 2014;10:179–196. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC. Key Points Passive sampling methods (PSMs) offer the potential for cost-efficient and accurate in situ characterization of the dissolved concentrations for inorganic sediment contaminants. PSMs are useful for evaluating the geochemical behavior of metals in surficial sediments, including determination of fluxes across the sediment-water interface, and post-depositional changes in metal speciation. Few studies have tried to link PSM responses in sediments to metal uptake and toxicity responses in benthic organisms. There is a clear need for further studies. Future PSMs could be designed to mimic saturable kinetics, which

  18. Heavy metals contamination potential and distribution in sediments of the River Turia, Spain

    NASA Astrophysics Data System (ADS)

    Pascual-Aguilar, Juan Antonio; Maiquez Moya, Mónica; Gimeno-García, Eugenia; Andreu, Vicente; Picó, Yolanda

    2016-04-01

    Knowledge on the state of waters and sediments of the rivers in the European Union is compulsory. Identification and quantification and monitoring of contaminants is somewhat established in the Water Framework Directive, so it can be acquired a reliable knowledge of the quality for further application of corrective messures can be developed when required. Heavy metals is one of the groups of contaminants that appear in the list of priority substances and in the legislation, so it is essential to attend its study to provide knowledge on the existing loads in different environmental matrices, such as sediments. This work presents a procedure that determines the presence and degree of concentration of a group of seven heavy metals (Co, Cd, Cr, Cu, Ni, Pb, and Zn) in the sediments of the River Turia, a typical Mediterranean River, located in the East of the Iberian Peninsula. The methodology includes their identification in two years (2012, 22 sampling points, and 2013, 27 sampling points). Two pollution index, one individual (Geo-accumulation Igeo, Igeo) that estimated the potential contamination of each metal and a synthetic one (Potential ecorisk index range, PERI) which gets the potential contamination of all 7 grouped applied to each set of data. In addition, to establish possible spatial patterns it has been developed an analysis of the distribution of both indicators and on both dates with Geographic Information Systems, for that purpose it has been divided the River into three segments: upper part (represented by 10 points in 2012 and 13 in 2013), middle part (with 7 points in 2012 and 6 in 2013) and lower section (with 5 points in 2012 and 8 in 2013). Results show that lower concentrations of contaminants were given in 2012 than in 2013. In 2012 the Igeo index, which is distributed in a qualitative range of seven categories ranging from low pollution to very high pollution, are only meaningful for Zn, with "low to moderate" pollution in 13 places (6 points in

  19. MINE WASTE TECHNOLOGY PROGRAM; PHOSPHATE STABILIZATION OF HEAVY METALS CONTAMINATED MINE WASTE YARD SOILS, JOPLIN, MISSOURI NPL SITE

    EPA Science Inventory

    This document summarizes the results of Mine Waste Technology Project 22-Phosphate Stabilization of Heavy Metals-Contaminated Mine Waste Yard Soils. Mining, milling, and smelting of ores near Joplin, Missouri, have resulted in heavy metal contamination of the area. The Joplin s...

  20. Elemental tracers of source regions of contaminants in precipitation. First quarterly report, November 1, 1984-October 31, 1985

    SciTech Connect

    Rahn, K.A.

    1985-03-01

    Start-up accomplishments associated with the project are discussed. This includes equipment acquisition, testing of contamination of sample containers (sandwich bags) and preliminary sampling and analysis of atmospheric precipitations. 2 tables. (MDF)

  1. Release of metals from a Cd-contaminated streambed in response to experimental acidification and neutralization

    NASA Astrophysics Data System (ADS)

    Curtis, P. Jefferson; Walker, Paddy

    1994-12-01

    Short-term (hours) experimental acidification of a Cd-contaminated Precambrian Shield stream with low buffering capacity caused the release of Ca, Mg, Cd, Mn, Fe, and Al from the streambed. Release of metals was consistent with pH-dependent desorption and dissolution of amorphous hydroxides. Partial neutralization of the stream with MgCO3 inhibited metal release for most metals; however, excess Mg appeared to stimulate Cd release. Thus addition of Mg (and probably Ca) compounds to neutralize acidified water may be ineffective for reducing Cd concentrations in solution because added base cations apparently compete with Cd for adsorption sites.

  2. The effect of heavy metal contamination in SIMOX on radiation hardness of MOS transistors

    NASA Astrophysics Data System (ADS)

    Ipri, Alfred C.; Jastrzebski, L.; Peters, D.

    1989-12-01

    It is shown that heavy-metal contamination introduced during implantation of oxygen into silicon results in a reduction of SIMOX (separation by implanted oxygen) oxide radiation hardness. Radiation-induced back-channel leakage currents in MOS transistors processed in SIMOX films containing various levels of heavy metals, as measured by surface photovoltage (SPV), are a strong function of heavy metal concentration. It is concluded that SPV measurements of as-implanted SIMOX wafers can be used as a rapid nondestructive quality control inspection technique to predict the radiation hardness of the SIMOX oxide prior to processing.

  3. Temperature-dependent formation of metallic copper and metal sulfide nanoparticles during flooding of a contaminated soil

    NASA Astrophysics Data System (ADS)

    Hofacker, Anke F.; Voegelin, Andreas; Kaegi, Ralf; Weber, Frank-Andreas; Kretzschmar, Ruben

    2013-02-01

    Riparian floodplains in temperate regions are affected by pronounced seasonal variations in soil and water temperature. This affects the rates and interplay of microbial and abiotic geochemical processes that control the fate of metals in contaminated floodplain soils, including potential release into surface and groundwater during periodic flooding. Here, we investigated how temperature affects chalcophile trace metal contaminants (Cu, Cd, Pb) upon flooding of a riparian soil contaminated by past mining activities. In soil microcosms incubated at 23, 14, and 5 °C, the reductive dissolution of Mn(III,IV) and Fe(III) (oxyhydr)oxides and the release of dissolved Mn2+ and Fe2+ were significantly slower and less intense at the lower temperatures, which was reflected in a decrease of trace metal mobilization via the dissolution of metal oxide sorbents and cation competition for sorption sites. The onset of sulfate reduction was significantly delayed at lower temperatures and the apparent rate of sulfate reduction was decreased, especially at 5 °C. This resulted in elevated high dissolved Cu, Cd, and Pb concentrations over weeks of flooding at 5 °C, whereas colloidal metal sulfide formation dominated Cu, Cd, and Pb pore water dynamics at higher temperatures of 14 and 23 °C due to fast sulfate reduction. Cu K-edge X-ray absorption fine structure spectroscopy revealed metallic Cu(0) as the main colloidal Cu species prior to sulfate reduction at all three temperatures. Analytical electron microscopy showed that Cu(0) particles were associated with suspended bacteria, suggesting biomineralization of Cu(0). Upon onset of sulfate reduction, metallic Cu particles were transformed into CuxS with incorporation of smaller amounts of Cd and Pb. Concomitantly, freely dispersed mixed Cu-Cd-Pb sulfide nanoparticles precipitated in the pore water. Other metals with higher metal sulfide solubility products did not react with the limited amounts of biogenic sulfide. The median size

  4. Environmental remediation through sequestration of airfall-derived metals contamination by selective revegetation strategies

    NASA Astrophysics Data System (ADS)

    Sahagian, D.; Peters, S.; Yasko, G.

    2006-12-01

    Industrial activities in the 20th century left a legacy of contaminated air, water, and soils. The relative environmental enlightenment of the 21st century has already led to reductions in pollution sources, and has improved air and surface water quality in many areas. However, the residence time of contaminants in soils can be lengthy, presenting a challenge to 21st century restoration of impacted ecosystems and communities. The present study is centered on the Borough of Palmerton, PA, and a broad region of adjacent communities that were affected by two zinc smelters that operated continuously for more than 80 years, emitting thousands of tons of heavy metals including zinc, cadmium, lead and arsenic. While the air quality has vastly improved since the closure of the zinc smelters, the community remains adversely affected by the ecological damage caused by the pollution. The north face of the Kittatiny ridge was completely denuded of vegetation from the high metals concentrations. The region suffers further due to the ongoing perception of contaminated soils and water, leaving the town and surrounding areas economically depressed. In this study, we are examining the impact of revegetation strategies, particularly those using warm season grasses to determine which species survive and indeed thrive in the metals-contaminated soils. Because of the large areal extent and locally steep slopes in the broad area of concern, removal of metals from the entire region is impractical. It is considered more effective to sequester the metals in the soil so that they do not leach into the rivers, or enter the food web. Vegetation that absorbs and transports the metals throughout its tissues would mobilize these pollutants into the food web as well as make the metals available to reach the river via leaves and other vegetative structures. In this study, we are monitoring the uptake of metals by test grasses and other plants that are colonizing the contaminated area, as well as

  5. Metal contamination disturbs biochemical and microbial properties of calcareous agricultural soils of the Mediterranean area.

    PubMed

    de Santiago-Martín, Ana; Cheviron, Natalie; Quintana, Jose R; González, Concepción; Lafuente, Antonio L; Mougin, Christian

    2013-04-01

    Mediterranean climate characteristics and carbonate are key factors governing soil heavy-metal accumulation, and low organic matter (OM) content could limit the ability of microbial populations to cope with resulting stress. We studied the effects of metal contamination on a combination of biological parameters in soils having these characteristics. With this aim, soils were spiked with a mixture of cadmium, copper, lead, and zinc, at the two limit values proposed by current European legislation, and incubated for ≤12 months. Then we measured biochemical (phosphatase, urease, β-galactosidase, arylsulfatase, and dehydrogenase activities) and microbial (fungal and bacterial DNA concentration by quantitative polymerase chain reaction) parameters. All of the enzyme activities were strongly affected by metal contamination and showed the following inhibition sequence: phosphatase (30-64 %) < arylsulfatase (38-97 %) ≤ urease (1-100 %) ≤ β-galactosidase (30-100 %) < dehydrogenase (69-100 %). The high variability among soils was attributed to the different proportion of fine mineral fraction, OM, crystalline iron oxides, and divalent cations in soil solution. The decrease of fungal DNA concentration in metal-spiked soils was negligible, whereas the decrease of bacterial DNA was ~1-54 % at the lowest level and 2-69 % at the highest level of contamination. The lowest bacterial DNA decrease occurred in soils with the highest OM, clay, and carbonate contents. Finally, regarding the strong inhibition of the biological parameters measured and the alteration of the fungal/bacterial DNA ratio, we provide strong evidence that disturbance on the system, even within the limiting values of contamination proposed by the current European Directive, could alter key soil processes. These limiting values should be established according to soil characteristics and/or revised when contamination is produced by a mixture of heavy metals. PMID:23183935

  6. Reproductive success and heavy metal contamination in Rhode Island common terns

    USGS Publications Warehouse

    Custer, T.W.; Franson, J.C.; Moore, J.F.; Myers, J.E.

    1986-01-01

    Common tern cIutch size, reproductive success and growth of young recorded from an abandoned barge on the Providence River, an area of heavy metal contamination, were equal to, or greater than, .from less contaminated areas. Concentrations of copper and zinc were higher in livers of nestling terns from the Providence River than from other, less contaminated, areas. However, concentrations of magnesium, manganese, and iron and the frequency of nickel were equal, or lower, at Providence than other, less contaminated, locations. Among-colony trends in residues of copper, zinc and nickel in prey samples were similar to trends .found in nestling livers. Uric acid concentrations in nestling blood were twice as high in the Providence River than another colony and may have resulted from moderate levels of chromium in the diet.

  7. Reproductive success and heavy metal contamination in Rhode Island common terns

    USGS Publications Warehouse

    Custer, T.W.; Franson, J.C.; Moore, J.F.

    1986-01-01

    Common tern (Sterna hirundinae ) clutch size, reproductive success and growth of young recorded from an abandoned barge on the Providence River, an area of heavy metal contamination, were equal to, or greater than, from less contaminated areas. Concentrations of copper and zinc were higher in livers of nestling terns from the Providence River than from other, less contaminated, areas. However, concentrations of magnesium, manganese, and iron and the frequency of nickel were equal, or lower, at Providence than other, less contaminated, locations. Among-colony trends in residues of copper, zinc and nickel in prey samples were similar to trends found in nestling livers. Uric acid concentrations in nestling blood were twice as high in the Providence River than another colony and may have resulted from moderate levels of chromium in the diet.

  8. Analysis of disposition alternatives for radioactively contaminated scrap metal

    SciTech Connect

    Nieves, L.A.; Chen, S.Y.; Kohout, E.J.; Nabelssi, B.; Tilbrook, R.W.; Wilson, S.E.

    1997-01-01

    Millions of tonnes of slightly radioactive, scrap iron and steel, stainless steel, and copper are likely to become available as nuclear and other facilities and equipment are withdrawn from service. Disposition of this material is an international policy issue under consideration currently. The major alternatives for managing this material are to either develop a regulatory process for decontamination and recycling that will safeguard human health or to dispose of the scrap and replace the metal stocks. To evaluate the alternatives, we estimate quantities of scrap arising from nuclear power plant decommissioning, evaluate potential price impacts of recycling on regional markets, and assess the health and environmental impacts of the management alternatives. We conclude that decontaminating and recycling the scrap is the superior alternative.

  9. Accumulation of Heavy Metals in Vegetable Species Planted in Contaminated Soils and the Health Risk Assessment

    PubMed Central

    Zhou, Hang; Yang, Wen-Tao; Zhou, Xin; Liu, Li; Gu, Jiao-Feng; Wang, Wen-Lei; Zou, Jia-Ling; Tian, Tao; Peng, Pei-Qin; Liao, Bo-Han

    2016-01-01

    The objectives of the present study were to investigate heavy metal accumulation in 22 vegetable species and to assess the human health risks of vegetable consumption. Six vegetable types were cultivated on farmland contaminated with heavy metals (Pb, Cd, Cu, Zn, and As). The target hazard quotient (THQ) method was used to assess the human health risks posed by heavy metals through vegetable consumption. Clear differences were found in the concentrations of heavy metals in edible parts of the different vegetables. The concentrations of heavy metals decreased in the sequence as leafy vegetables > stalk vegetables/root vegetables/solanaceous vegetables > legume vegetables/melon vegetables. The ability of leafy vegetables to uptake and accumulate heavy metals was the highest, and that of melon vegetables was the lowest. This indicated that the low accumulators (melon vegetables) were suitable for being planted on contaminated soil, while the high accumulators (leafy vegetables) were unsuitable. In Shizhuyuan area, China, the total THQ values of adults and children through consumption of vegetables were 4.12 and 5.41, respectively, suggesting that the residents may be facing health risks due to vegetable consumption, and that children were vulnerable to the adverse effects of heavy metal ingestion. PMID:26959043

  10. Evaluating Insects as Bioindicators of Heavy Metal Contamination and Accumulation near Industrial Area of Gujrat, Pakistan

    PubMed Central

    Azam, Iqra; Afsheen, Sumera; Zia, Ahmed; Javed, Muqaddas; Saeed, Rashid; Sarwar, Muhammad Kaleem; Munir, Bushra

    2015-01-01

    To study the accumulation and contamination of heavy metals (i.e., Cd, Cr, Cu, Ni, and Zn) in soil, air, and water, few insect species were assayed as ecological indicators. Study area comes under industrial zone of district Gujrat of Punjab, Pakistan. Insects used as bioindicators included a libellulid dragonfly (Crocothemis servilia), an acridid grasshopper (Oxya hyla hyla), and a nymphalid butterfly (Danaus chrysippus) near industrial zone of Gujrat. Accumulation of Cd was highest in insect species followed by Cu, Cr, Zn, and Ni at p < 0.05. Hierarchical cluster analysis (HACA) was carried out to study metal accumulation level in all insects. Correlation and regression analysis confirmed HACA observations and declared concentration of heavy metals above permissible limits. Metal concentrations in insects were significantly higher near industries and nallahs in Gujrat and relatively higher concentrations of metals were found in Orthoptera than Odonata and Lepidoptera. The total metal concentrations in insects were pointed significantly higher at sites S3 (Mid of HalsiNala), S9 (End of HalsiNala), and S1 (Start of HalsiNala), whereas lowest value was detected at site S6 (Kalra Khasa) located far from industrial area. HACA indicates that these insect groups are potential indicators of metal contamination and can be used in biomonitoring. PMID:26167507