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1
Kalnejais, Linda H. "Mechanisms of metal release from contaminated coastal sediments." Thesis, Online version, 2005. http://hdl.handle.net/1912/1715.
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Hill, Nicole Ann Biological Earth & Environmental Sciences Faculty of Science UNSW. "Impacts of metal-contaminated sediments: a temperate-polar investigation." Publisher:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/43765.
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Contaminated sediments pose a direct risk to sediment fauna and have the potential to affect other benthic assemblages. Disturbances that resuspend and remobilise contaminants may impact on filter-feeding, hard-substrate organisms that live immediately above sediments. This thesis uses laboratory and field manipulations to examine the impact of metal-contaminated sediments on sediment fauna and hard-substrate fauna simultaneously. It also compares the response of assemblages to metal contamination in a temperate and polar ecosystem. Simulated resuspension exposures in the laboratory indicated that contaminated sediments have the potential to affect hard-substrate organisms. Spirorbid polychaetes responded to both aqueous metals and to resuspended, particulate-bound metals. Impacts on hard-substrate fauna were however, not observed in manipulative field experiments using metal-spiked sediments. The recruitment and cover of hard-substrate organisms were either not affected or enhanced above contaminated sediments. In contrast, metal contamination had direct negative effects on sediment fauna, with a reduction in the abundance of most taxa. Results suggest that sediment fauna may interact with hard-substrate fauna through physical and/or biological mechanisms. In a reciprocal transplant experiment, established Antarctic hard-substrate assemblages were also unaffected by contaminant concentrations at an impacted site. Overall, metal-contaminated sediments are unlikely to pose as serious a threat to hard-substrate fauna as they do to sediment fauna. Contaminated sediments are not restricted to industrialised regions, and human activities in Antarctica have resulted in localised contamination near research stations. Although Antarctic assemblages are thought to be more sensitive than temperate assemblages to contaminants, few studies have explicitly examined this. Little evidence was found to support the theory that Antarctic assemblages are more susceptible to contaminated sediments. The response of Antarctic and temperate assemblages in the field to metal-contaminated sediments over a 10-11 month period was comparable. Responses were of a similar magnitude, despite differences in the composition of assemblages. In 10-d toxicity tests, the mortality of a common Antarctic hard-substrate organism was relatively insensitive to aqueous Cu, Zn and Pb. These results suggest that using current sediment quality guidelines from Australia may be a useful screening tool to assess the risk associated with contaminated sediments in Antarctica.
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Lynch, Sarah Francesca Lynn. "Establishing the environmental risk of metal contaminated river bank sediments." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6266/.
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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, however 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 exceeded environmental quality standards. Key mechanisms controlling mobility were (i) anglesite solubility control of dissolved Pb, (iii) evaporation, precipitation and dissolution of Zn sulphate salts, (iii) oxidation of galena and sphalerite, (iv) reductive dissolution 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.
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Milum, Kristen Marie. "In Situ Remediation of Heavy Metal Contaminated Sediments Using Emulsified Zero-Valent Metal Particles." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3305.
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Sediments can act as both a sink for pollutants and a source for aquatic contaminants. Natural and human disturbances of the sediments can release the contaminants to the overlying water where bottom dwelling, or benthic, organisms may be exposed through direct contact, ingestion of sediment particles, or uptake of dissolved contaminants present in the water. Dredging, the most common remediation technology for heavy metals, exacerbates this process. The in situ use of emulsified metal has been studied for its ability to pull heavy metals from aqueous solution and from saturated soils. It has proven successful in the laboratory with removal of lead, cadmium, copper, nickel, and uranium from aqueous solution and removal of lead and cadmium from saturated spiked soils. The use of zero-valent metal particles, particularly those of zero-valent iron (Fe0), as an in situ remediation technique, is currently undergoing evaluation. The basic mechanism for removal appears to be reduction of contaminant metals followed by the subsequent precipitation of their insoluble forms. This is accompanied by the oxidation of the zero-valent metal. In the case of iron, Fe0 undergoes oxidation to Fe2+ and then to the Fe3+ state. Particulate Fe0 has been shown to precipitate Cr6+ to Cr3+ and Pb2+ undergoes reduction to Pb0. Initially, zero-valent iron filings were used to reduce the metal contaminants, but it has been shown that smaller size iron particles, such as nano-scale iron, have higher initial reduction rates as well as a higher concentration of contaminant removal per mole of iron. Emulsion liquid membrane (ELM) technology has been employed as a remediation technique for the removal of metals from wastewater where extraction and stripping processes are performed in a single operation. The ELMs are made by forming an emulsion between two immiscible liquids, such as oil and water, and are often stabilized by a surfactant. We have attempted to demonstrate the application of the combination of these two technologies through the use of emulsified zero-valent metal (EZVM) to treat sediments with heavy metal contamination. Emulsions were prepared using vegetable oil, water, Span 85, and either nanoscale Fe, 1-3 [micro]m Fe, 4 [micro]m Mg, or a 20 wt % Fe-Mg mixture. The results presented in this study demonstrate that EZVM is a viable technique for in situ remediation of heavy metals in sediments. Laboratory scale studies have shown high levels of removal of lead and cadmium from solution using emulsified zero-valent iron. Additionally, the use of emulsified magnesium has shown the ability for high levels of removal of copper, cadmium, nickel, lead, and uranium from solution. A variety of solution matrices were also explored for a lead solution including seawater, the presence of complexing agents and humic acids. Small-scale laboratory studies have shown 65% removal of lead and 45% removal of cadmium from saturated, spiked soils. A bench scale test to demonstrate the applicability of this technique in the environment revealed similar results for the removal of lead.M.S.
Department of Chemistry
Arts and Sciences
Industrial Chemistry
5
Chariton, Anthony A., and n/a. "Responses in estuarine macrobenthic invertebrate assemblages to trace metal contaminated sediments." University of Canberra. Resource, Environmental & Heritage Sciences, 2005. http://erl.canberra.edu.au./public/adt-AUC20060509.115744.
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Three approaches were employed to examine the effects of elevated sediment trace
metal concentrations on estuarine/marine macrobenthic invertebrate assemblages. The
initial study examined macroinvertebrate communities along a known polymetallic
gradient, Lake Macquarie, NSW (gradient study). The second study experimentally
tested if sediments sourced from different locations within Lake Macquarie
differentially influenced the recolonisation of benthic invertebrates. The third study
investigated the different recolonisation patterns of benthic invertebrates into
sediments spiked with increasing concentrations of sediment-bound cadmium.
In the Lake Macquarie gradient study, four locations (Cockle Bay, Warner's Bay,
Kooroora Bay and Nord's Wharf) were sampled in winter 2000 and summer 2003
using a hierarchical design (location > site > plot). On both sampling occasions, the
sediments showed strong gradients in lead, cadmium and zinc concentrations
emanating from the Cockle Bay industrialised region in the lake's north, with
concentrations being significantly lower in the most southern and less urbanised
location (Nord's Wharf). In general, concentrations of lead, cadmium and zinc in the
sediments increased among locations in the following order: Nord's Wharf >
Kooroora Bay > Warner's Bay > Cockle Bay. AVSJSEM analyses indicated that in
some sites in Cockle Bay, and to a lesser extent Warner's Bay, SEM concentrations
exceeded their molar equivalence of AVS, indicating the potential for trace metals to
be labile within the porewaters. Granulometry also changed along the gradient, with a
higher proportion of silt/clay occurring in the locations with high metal
concentrations. Conversely, the percentage of total organic carbon was higher in the
less contaminated locations.
In winter 2000, changes in benthic communities along the gradient supported the a
priori hypotheses, with diversity and richness being greater in locations with lower
concentrations of metals. Polychaetes were most numerous in Cockle Bay and
Warner's Bay, whilst bivalves and gastropods were more abundant in Nord's Wharf
and Kooroora Bay. Crustaceans were more numerous in Nord's Wharf; with all other
locations having similar, lower, abundances. Ordination maps of the assemblages
provided relatively clear separation of the assemblages among locations, with nonparametric
multivariate analysis of variance (NPMANOVA) and subsequent pair-wise
comparisons finding significant differences among the assemblages from all locations.
SIMPER analyses found the highest level of dissimilarity was between the Nord's
Wharf and Cockle Bay assemblages - primarily attributable to differences in the
relative contributions of isopods; tellenid bivalves; and the polychaete families
Spionidae, Opheliidae and Nephytidae. Weighted Spearman rank correlations (BIOENV)
identified cadmium (Pw =0.74) as the strongest environmental (single or
combination) variable to correlate with biotic assemblages.
Benthic patterns along the gradient were less defined in summer 2003 due to a
dramatic reduction in the abundance and diversity of fauna in Nord's Wharf. This
decline was possibly attributable to a sustained reduction in salinity caused by a
prolonged rainfall event. With the exception of Nord's Wharf, trends in the
community indices and abundances of key taxa among the other locations were
similar to those reported in winter 2000. Multivariate analyses discriminated the
benthic assemblages from the four locations, with the findings from the NPMANOVA
pair-wise comparisons indicating that the assemblages from all four locations were
significantly different. SIMPER analyses showed the highest level of dissimilarity
was between Nord's Wharf and Warner's Bay, with these differences being primarily
attributable to their relative abundances of amphipods and polychaetes from the
families Spionidae, Cirratulidae, Opheliidae and Capitellidae. BIOENV found that the
combination of the sedimentary concentrations of cadmium and iron provided the best
correlation (Pw =0.73) with biotic patterns, with similar correlations occumng with
the addition of lead and its covariate, zinc (Pw =0.72).
The combined findings from the gradient study established a strong correlation
between trace metal concentrations within the sediments and suite of univariate and
multivariate measurements. The low abundance and diversity of fauna in Nord's
Wharf in the summer of 2003 highlighted the dynamic changes which can occur in the
distributions of macrobenthic invertebrates. Although the study indicated that there
was a strong relationship between trace metal concentrations and benthic community
structure, the study was correlative, and requires subsequent experimental testing to
confirm the causality of the observed relationships.
The second component of the research was a translocation experiment using benthic
recolonisation as an end-point. The experiment was performed to identify if the
sediments, and not location, were influencing the composition of benthic assemblages
in Lake Macquarie. Sediments were collected from three locations (Cockle Bay,
Warner's Bay and Nord's Wharf), defaunated, and transplanted in three new locations
along the south-east edge of the lake. At each location, 10 containers of each
treatment were randomly placed in the sediment and allowed to recolonise for 22
weeks. Upon retrieval, the benthic communities were sampled and enumerated in
conjunction with a variety of chemical and sedimentary measurements. Ten replicate
invertebrate samples were also collected in the sediments adjacent to the experiment
(ambient samples) at the completion of the experiment. Due to human interference,
the containers from only two locations were analysed.
Upon retrieval, pH and redox profiles of the sediments were similar to those expected
in natural sediments. In general, concentrations of metals were low in the porewaters;
however, iron precipitation on the porewater collection devices may have artificially
increased the diffusion of metals, increasing concentrations near the sediment-water
interface. Concentrations of SEM exceeded their AVS equivalence in some samples
taken from the Cockle Bay and Warner's Bay treatments.
Two-way ANOVAs found significant interactions between location and sediment
treatments in diversity, evenness and the number of polychaetes, as well as significant
differences in the number of capitellids and crustaceans among locations. Post-hoc
comparisons of means found the Nord's Wharf sediment contained a higher mean
number of individuals than the other treatments, including the ambient samples.
nMDS ordination plots for both locations provided poor graphical discrimination of
the assemblages among treatments; however, NPMANOVA detected significant
location and treatment interactions. In both locations, pair-wise comparisons indicated
that the assemblages within the Nord's Wharf treatments were significantly different
to the Cockle Bay, Warner's Bay and ambient assemblages. No significant differences
were detected between the Cockle Bay and Warner's Bay assemblages at either
location. SIMPER analyses found the highest level of dissimilarity occurred between
the ambient assemblages in Location 2 and the Nord's Wharf treatment, primarily due
to the relative difference in the abundances of Capitellidae, Spionidae, Oweniidae,
Nereididae and isopods among the assemblages.
The findings from the translocation experiment suggest that the sediments are
influencing the recolonisation of benthos. However, because differences were not
detected between the Cockle Bay and Warner's Bay treatments, the approach used in
the study shows potential as an in situ technique which could be used to assess the
potential ecological risks of sediments fiom specific locations. Excluding cost and
time considerations, the technique's primary disadvantage is the lack of a true control.
As a result, the technique can only identify if the sediments are modifying benthic
recolonisation, and not causality.
The final component of the research experimentally tested if elevated concentrations
of sediment-bound cadmium affected benthic invertebrate recolonisation. Sediments
from the south coast of New South Wales (Durras Lake) were defaunated, and spiked
with cadmium under anaerobic conditions to obtain three targeted cadmium
concentrations: control (
6
Torre, Bianca Maria. "Evaluating metal toxicity in contaminated sediments in the South of Spain." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/12206/.
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Coastal zones are ecologically important areas subject to heavy anthropogenic pressures such as urbanization, fishing, commercial transports, as well as industrial and agriculture activities. In this context, Huelva, in the south of Spain, is a polluted area due to these reasons. In order to evaluate the consequences of anthropogenic impacts in the coastal area of Huelva, sediments from three different sites (Bay of Cádiz, Muelle de Capesa and Mazagòn) were assessed using an integrated model. This methodology integrates sediment physical-chemical parameters and biological responses in test organisms. Metal concentrations (Cr, Cu, Fe, Mn, Ni, Pb, Zn) and organic matter content were measured as physical-chemical parameters. Biological responses were assessed using three bioassays in two marine species: Mortality for Ampelisca brevicornis and Fertilization and Larval development for Paracentrotus lividus. The test organisms were exposed under two different routes of exposure (whole sediment or elutriate). Acute effects associated with the presence of metals (Cr, Cu, Fe, Mn, Ni, Pb, Zn) were observed and resulted correlated with the abnormal fertilization and larval development of echinoderms exposed to the sediments. The results here obtained were useful to confirm that the high level of metals contamination found in Huelva area, when compared to the control site (Bay of Cádiz), is likely to pose adverse effects on marine resident biota.
7
Guan, Dongming Loew Sabine Susanne. "Fitness, developmental stability, and germline mutation rates in white-footed mice (Peromyscus leucopus) chronically exposed to heavy metal contamination." Normal, Ill. : Illinois State University, 2007. http://proquest.umi.com/pqdweb?index=0&did=1414115231&SrchMode=1&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1207663717&clientId=43838.
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Thesis (Ph. D.)--Illinois State University, 2007.Title from title page screen, viewed on April 8, 2008. Dissertation Committee: Sabine S. Loew (chair), Steven A. Juliano, Charles F. Thompson, Angelo P. Capparella, William L. Perry. Includes bibliographical references (leaves 143-173) and abstract. Also available in print.
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Thuy, Nguyen Lan. "Mobilization of metals from mining wastes and the resuspension of contaminated sediments." Doctoral thesis, Linköpings universitet, Tema vatten i natur och samhälle, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10008.
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In some environmental situations, environmental effects caused by elevated metals resulting from past mining and smelting activities can be observed in nearby receiving water bodies several decades after mine and smelter closure. There is a growing need for managing the hazardous solid wastes such as mining wastes as well as for assessing water quality and for sustainable management of sediment quality. The work presented in this thesis examined the mobilization of metals from two metal sources: mining wastes from a mine site in Vietnam and sediments from a contaminated lake in Sweden in order to test the hypothesis that mobilization of metals will be increased, when the environmental conditions change by e.g. exposure of mining wastes to oxidative weathering, change of redox conditions at the water-sediment interface and resuspension of sediments. The results from this work under field and laboratory conditions have verified the hypothesis. The exposure of sulphidic mining wastes in oxidative weathering conditions may cause long-term production of ARD and the resultant long-term mobility of metals. The oxidation/resuspension of sediments is an important factor for the release of trace metals Zn, Cu and Cd into the solution and substantial amounts of particles and, hence, associated metals into overlying water. The concomitant changes in pH during oxidation/resuspension of sediment play a significant role in the metal release both to redox sensitive elements Fe and Mn and trace elements Zn, Cu and Cd. The concomitant change in DOC during oxidation/resuspension can also contribute to the increased mobility of study metals. The field study was coupled to intermittent operation of a hydropower plant. The mobility of the metals was higher under operation compared to non-operation and, thus, the potential impacts on dispersal of metal pollution to downstream aquatic environments. The sudden increase in water flow upon the hydropower plant upon shifts from inactive to active state could cause immediate release of particles and thus particulate metals in the overlying water. However, the magnitude and its integrated effects in fluxes of metals over the season call for further research. There is a need to further investigate the impacts of hydropower generation in a longer period of time and at a higher frequency of observations at the very start of the hydropower operation. The results from this multidisciplinary approach would give a basis for an optimal operation of the hydropower plant to minimize the metal pollution associated with the water flow.The series number is changed from 410 to 430 and the ISBN is changed from 978-91-85895-56-4 to 978-91-7393-926-3.
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Chau, Kwok-chuen, and 周國銓. "Metal enrichment in the sediment profile of Deep Bay, Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50534245.
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Deep Bay is located in the northwestern coast of Hong Kong (HK), where brackish water from the Pearl River Estuary meets and interacts with fresh water from Shenzhen River and Yuen Long Creek. A review of published material in this study indicates rapid economic and industrial developments can be found in Hong Kong and Pearl River Delta (PRD) region in the last 60years, which would have contaminated the sediment in Deep Bay with heavy metals. To examine the nature of metal contamination history, two 2m-long sediment cores are collected from the mud flat of Deep Bay, and the chemical and physical properties of the sediment sequence analyzed. Small disturbance of sediment profile is observed by the fluctuation of 210Pb signal, and constant rate of supply (CRS) model is applied for the calculation of sedimentation rate which is estimated to be 1.82cm/year.137Cs dating resolves two peaks for the radionuclide at 28cm and 109cm, as well as the onset of excessive 137Cs activity at 135cm, which are connected to the Chernobyl accident in 1986 and the banning and beginning of atmospheric testing of nuclear weapons in 1963 and 1950 respectively. Particle size analysis shows the core sediments are predominantly silt (4-64μm) and clay(<4μm). Enrichment factor of metal concentration displays that Cd, Cr, Cu and Zn has been significantly enriched since the 1950s, and hence 3 phases of metal enrichment could be identified: 1) insignificant anthropogenic input in preindustrial period before 1950, 2) significant enrichment of metal from anthropogenic sources during industrial stage in HK from 1950 to 1980, and 3) a further increase of metal enrichment after the introduction of new town development in northwestern part of HK and Chinese economic reform since 1980. Among the metals in the sediments at depth over 70cm, Cu and Zn are found to be exceeded the Lower Chemical Exceedance Level of the sediment quality criteria given by the Hong Kong Environmental Protection Department; hence, the metals would impose threats to the natural environment once they are released back to water column by changes to physical conditions. To evaluate the extent of environmental threats, future studies could focus on the bioavailability of the metals and the interaction of metals in sediments and water with organisms in the ecosystem of Deep Bay.published_or_final_version
Earth Sciences
Master
Master of Philosophy
10
Maxwell, Deborah. "REMEDIATION OF HEAVY METAL CONTAMINATION IN SEDIMENTS: APPLICATION OF IN SITU TREATMENT UTILIZING EMULSIFIED LIQUID MEMBRANE AN." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4329.
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Heavy metal contamination of soils, sediments and groundwater presents an ongoing source of hazardous and persistent environmental pollution. How best to remediate these contaminants is the impetus of continuing research efforts. Methods include containment, ex situ and in situ techniques. A successful in situ method utilizing a combination of emulsified liquid membranes, ELM, and zero-valent metal, ZVM, and bimetals has demonstrated impressive heavy metal reduction in 100 ppm solutions of Cd, Cu, Ni, Pb, Cr and U. This promising in situ method has been employed by the Industrial Chemistry Laboratory at the University of Central Florida and it has demonstrated considerable success in treating several environmental threats. Contaminated soils, surfaces, sediments and groundwater with offending agents such as trichloroethene, polychorobiphenyls and heavy metals have been treated utilizing emulsified liquid membrane systems containing zero-valent iron or bimetal particles. In vial studies, lead spiked sediments have shown repeatable 60% removal of lead after seven days of treatment. A persistent pattern emerged at ten days whereupon remediation levels began to drop. The current study was established to determine the reason for the decline at ten days and beyond. Questions addressed: Does the formation of an impeding oxide layer diminish the remediation capacity of the iron/magnesium system? Does the emulsion reach a maximum capacity to withdraw the contaminant? Do the soil components or the soil structure interfere with the access to the contaminant? This study has yielded insight into the reasons emulsified liquid membrane systems containing zero-valent metals achieved maximum lead removal at day seven, and thereafter begin to lose their effectiveness. A three part study was implemented to address and to answer the three questions pertaining to the consistent pattern of diminishing remediation levels exhibited at day ten and beyond. Initially, from Study I results it appeared that the formation of an impeding oxide layer on the bi-metal which was inside the emulsion droplet and which plated or precipitated with the lead was not occurring at day ten. Results indicated that the iron/magnesium was still capable of removing lead. Furthermore, from Study II results the emulsion dose injected appeared adequate to remove the lead, meaning that the emulsion had not reached its maximum capacity for remediation. The emulsion dose was not a limiting factor. Lastly, Study III results seemed to indicate that the drop in remediation after day seven pertained to the soil structure. There appeared to be some merit to the idea that with aging of the sediment, the lead was diffusing and migrating to some inaccessible interior sites within the sediment particles. Additionally, indications from day ten and day fourteen delineated that a second emulsion dose injection might restore lead removal levels to approach those first observed at day seven and consequently be a useful field application. In order to explore the effectiveness of injecting a second dose of emulsion, another vial study was implemented. The typical pattern of observing sixty percent maximum lead removal at day seven was observed. In separate groups, a second injection of emulsion was added at day five, and then for another vial series, a second dose was added at day seven. The second emulsion dose treatment for either day five or day seven did not yield any increases in percent lead removal. Another theory emerged after viewing micrographs of recovered iron/magnesium compared with fresh ball-milled bimetal. In addition, scanning electron microscopy appeared to confirm the explanation that the emulsified zero-valent metal system might be compromised after day seven. This would lead to exposure of the iron/magnesium to the air and the elements. Corrosion of the bimetal might be occurring. With time, release of the plated or precipitated lead back into the sediment mixture could follow. The results of Study I had led to the conclusion that an impeding oxide layer had not formed; however, this conclusion may have been premature because the recovered iron/magnesium was exposed to lead solution in the vial study. Perhaps if the recovered iron/magnesium was inserted back into an emulsion and injected into lead spiked sediments the percent lead removed might give a more accurate picture of the iron/magnesium's capability to continue performing remediation. Remediation of sediments contaminated with lead is a complicated task because of the complex nature of sediment components. Emulsified liquid membranes utilizing zero-valent bimetals has repeatedly demonstrated impressive results at day seven; however, this treatment method is not without its limitations. Optimal results appear to be gained at day seven after emulsion injection. The bimetal and plated or precipitated lead must be removed at that point; otherwise the effective remediation of the contaminant is progressively reversed.M.S.
Department of Chemistry
Sciences
Industrial Chemistry MS
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Kwok, Chun Kit. "Toxicological assessments of PAHs, OCPs and heavy metals in sediments at Mai Po and Deep Bay, Hong Kong." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/875.
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Moberly, James Gill. "Biogeochemical cycling of toxic metals in Lake Coeur d'Alene sediments." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/summer2006/J%5FMoberly%5F063006.PDF.
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Evans, Dyfed. "Fluvial dispersal of heavy metals in contaminated soils and sediments." Thesis, University of Bradford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334773.
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馬依琪 and Yee-ki Ma. "Fractionation, release and adsorption of heavy metals in contaminated marine sediments." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31227685.
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Rehman, Fayaz Ur. "Solid state speciation of metals in hydrothermal and contaminated marine sediments." Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317220.
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Nguyễn, Thúy Lan. "Mobilization of metals from mining wastes and the resuspension of contaminated sediments /." Linköping : Department of Waters and Environmental Studies, Linköping University, 2008. http://www.bibl.liu.se/liupubl/disp/disp2008/arts430s.pdf.
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Dragana, Tomašević. "Primena stabilizovanog nano nula valentnog gvožđa i komercijalnih imobilizacionih agenasa za remedijaciju sedimenta kontaminiranog toksičnim metalima." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2013. https://www.cris.uns.ac.rs/record.jsf?recordId=86532&source=NDLTD&language=en.
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Predmet istraživanja ove disertacije je mogućnost korišćenja nano nulavalentnog gvožđa stabilizovanog sa bentonitom, kaolinitom i karboksimetilcelulozom za imobilizaciju teških metala, kao i ponašanje i sudbina metala usedimentu. Istraživanja je usmero u dva pravca: prvi deo istraživanja ima za cilj,pre svega da definiše bolje razumevanje ponašanja metala u sedimentu iodređivanje njihove potencijalne mobilnost, biodostupnost i potencijalnetoksičnost na osnovu metoda sekvencijalne ekstrakcione procedure, kiselovolatilnog sulfida i simultano ekstrahovanih metalau netretiranim i tretiranimuzorcima sedimenta. Takođe, određena je efikasnosti korišćenja nanomaterijalaza imobilizaciju metala u sedimentu iz tretiranih smeša korišćenjem tzv. testova„izluživanja“ kao i definisanje dominantnog mehanizma izluživanja kojiomogućava transport metala. Drugi deo istraživanja ima za cilj ispitivanjemogućnosti primene nano nula valentnog gvožđa obloženog sa bentonitom,kaolinitom i karboksimetilcelulozom za tretman zagađenog sedimenta na lokaciji(in-situ), uz određivanje potencijalnog rizika po okolinu na osnovu rezultatasekvencijlane ekstrakcione procedure i ekstrakcija u jednom koraku nakontretmana. Primenjeni su i modifikovani testovi izluživanja sa ciljem što boljesimulacije realnih uslova. Rezultati dobijeni simulacijom ovih uslova i daljomkarakterizacijom smeša, kako sa nanomaterijalom tako i smeša sa glinom,omogućuju izradu modela ponašanja metala u smislu dugoročnog "izluživanja" iztretiranog (stabilizovanog) sedimenta kao i procenukoji materijali su efikasnijiza imobilizaciju toksičnih metala u sedimentu.This thesis explores the possibility of using nano zero valent iron stabilized withbentonite, kaolinite, and carboxymethyl cellulose for the immobilization of heavymetals, as well as the behaviour and fate of metalsin sediments. Research is focusedin two directions: the first part of the study aimsto find a better understanding of thebehaviour of metals in sediments and to determine their potential mobility,bioavailability and potential toxicity based on sequential extraction procedures andacid volatile sulphides and simultaneously extracted metals methods, in untreated andtreated sediment samples. The efficacy of using nanomaterials for the immobilizationof metals in sediments is also determined, by applying "leaching" tests to the treatedmixtures and defining the dominant leaching mechanism that enables the transport ofmetals. The second part of the study aims to examine the possibilities of applyingnano zero valent iron coated with bentonite, kaolinite and carboxymethyl cellulose forthe treatment of contaminated sediment in-situ, to determine the potential risk posedto the environment after treatment, based on the results of sequential extractionprocedures and a single step extraction. Modified leaching tests were applied in orderto achieve better simulation of real conditions. The results of simulating theseconditions and further characterization of mixtureswith both nanomaterials and clay,provide a long term "leaching" model for the behaviour of metals in the treated(stabilized) sediments, as well as assessing which materials are most effective for theimmobilization of toxic metals in sediments.
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Milena, Dalmacija. "Procena potencijala remedijacije sedimenta primenom imobilizacionih agenasa." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2010. https://www.cris.uns.ac.rs/record.jsf?recordId=23723&source=NDLTD&language=en.
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Predmet izučavanja ove disertacije je ispitivanje mogućnosti imobilizacije toksičnih metala u sedimentu primenom imobilizacione tehnike solidifikacije/stabilizacije portland cementom, kalcijum-oksidom, prirodnim zeolitom, letećim pepelom, kaolinitom, montmorilonitom, i različitim smešama ovih agenasa kao i određivanje njihove efikasnosti u zavisnosti od brojnih faktora. Efikasnost imobilizacionih postupaka praćena je korišćenjem tzv. testova izluživanja, odnosno određivanjem koncentracije metala koji su u toku određenog vremena iz imobilisane faze prešli u mobilnu fazu gde se smatraju potencijalno opasnim i biodostupnim. Krajnji cilj svakog testa izluživanja je mogućnost procene adekvatnosti primene određene imobilizacione, odnosno remedijacione tehnike. Efikasnost imobilizacionih postupaka zavisi i od određenih osobina: pH rastvora, dodatka imobilizacionog agensa što je istraživanjem ispitano. Na osnovu ovog testa, odnosno odnosa kumulativne frakcije metala koja je oslobođena iz imobilizacione smeše u mobilnu fazu i vremena određen je tip mehanizma koji omogućava transport metala (spiranje, difuzija, rastvaranje). Takođe su određeni i i parametri (koeficijenti difuzije, indeksi izlužljivosti) koji će poslužiti za ocenu efikasnosti prethodno primenjenih imobilizacionih tehnika. Primenjeni su i modifikovani testovi izluživanja sa ciljem što bolje simulacije realnih uslova. U modifikovanim testovima izluživanja korišćen je rastvor sa pH 3,25 da bi se simulirali uslovi koji oponašaju kisele kiše, odnosno uslovi u realnom sistemu. Takođe je koršćen i rastvor huminskih materija sa ciljem simulacije uslova velikog organskog opterećenja do kojeg bi moglo doći u slučaju akcidentnih situacija (na primer poplava) i generalno uslova koji se stvaraju u prirodi pri raspadanju organskog materijala (lišće, trava, itd.). Rezultati dobijeni simulacijom ovih uslova će dalje omogućiti modelovanje ponašanja metala u smislu dugoročnog "izluživanja" iz tretiranog sedimenta kao i procenu najefikasnijih agenasa za imobilizaciju različitih metala u sedimentu. Na osnovu dobijenih rezultata, zaključeno je da su optimalni agensi za imobilizaciju metala u sedimentu smeša cementa i kreča (5% cementa i 10% kreča), smeša montmorilonita i kreča (30% montmorilonita i 10% kreča), leteći pepeo (30%) i zeolit (30%). U ovim smešama dominantan mehanizam izluživanja je difuzija, a ove smeše se mogu smatrati inertnim otpadom po svim ispitivanim kriterijumima. Ovi rezultati se mogu upotrebiti za projektovanje i izgradnju pilot postrojenja na kome bi se ispitala efikasnost ovih agenasa za remedijaciju sedimenta u realnim uslovima. Dobijeni podaci su neprocenjivi sa aspekta ekonomski i ekološki prihvatljivog upravljanja sedimentom.This work is concerned with exploring the possibilities of immobilization of toxic metals in sediments using solidification/stabilization as imobilization technique and using Portland cement, calcium oxide, natural zeolite, flying ash, kaolinite, montmorilonite, and various mixtures of these agents and determine their effectiveness depending on many factors. Performance of imobilization procedures was followed by the use of so-called leaching tests and determination of the metals concentration that are within a specified interval of time leached from the immobile phase and as such can be considered potentially hazardous and bioavailable. The ultimate goal of every leaching test is to assess the adequacy of the possibility of applying certain imobilization or remediation technique. Performance of imobilizaction procedures depends on certain characteristics: pH of solution, additon of imobilization agent, etc. Based on this test, ie relation between the cumulative fraction of metal leached from imobilization mixture and time, the type of leaching mechanism that allows the transport of metals (wash-off, diffusion, dissolution) was determined. Other parameters which will serve for evaluating the efficiency of the previously applied imobilization techniques (diffusion coefficients, leaching indices) were also determined. Modified leaching tests were applied with the aim of better simulation of real conditions on the field. In the modified leaching tests the solution with pH 3.25 was used to simulate conditions that mimic acid rain and conditions in the real system. The humic acid solution was also used with the aim to simulate high organic loads which could occur in the case accident situation (eg floods) and the general conditions that are created in naturewhen decaying organic material (leaves, grass, etc.). The results obtained by simulating these conditions will enable the modeling of behavior of metals in terms of long-term leaching period from the treated sediment and assess the most effective agents for the immobilization of various metals in the sediments. Based on these results, it was concluded that the optimal agents for immobilization of metals in the sediment mixture of cement and lime (5% cement and 10% lime), a mixture montmorilonite and lime (30% montmorilonite and 10% lime), fly ash (30%) and zeolite (30%). In these mixtures dominant leaching mechanism is diffusion, and these mixtures can be considered as inert waste by all tested criteria. These results can be used to design and builda pilot plant in which order to evaluate the effectiveness of these agents for remediation of sediment in real terms. The obtained data are invaluable from the aspect of economic and ecologically acceptable management of sediment.
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Shumba, Trust. "Removal of heavy metals from CRUD and slime dam material using soil washing and bioremediation." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1536.
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Voyles, Joseph Stephen. "Geochemical Microelectrodes for the In Situ Monitoring of Metals Concentration and Mobility in Contaminated Sediments." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385980880.
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D'sa, Jean V. "Rapid removal of toxicity of acid mine drainage contaminated sediments in a clean stream : relative contribution of acidity vs metals /." Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1087840199.
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Royle, Anna. "Characterisation and remediation of a canal sediment contaminated with heavy metals and organic pollutants." Thesis, Liverpool John Moores University, 2005. http://researchonline.ljmu.ac.uk/5790/.
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Shumskykh, Mykyta. "Release of trace elements from contaminated sediments into surface waters during sediments dynamics : an experimental study." Thesis, Tours, 2019. http://www.theses.fr/2019TOUR4008.
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Dans les systèmes aquatiques, la plupart des éléments traces métalliques (ETM) sont piégés dans les sédiments puis peuvent être relargués en fonction des conditions chimiques et de l’activité microbienne à l’interface eau-sédiment. L’objectif de cette étude était d’évaluer l’impact de remise en suspension des sédiments (lors de crues et d’opérations de gestion de barrages) sur la mobilité de certains ETM. Plusieurs conditions expérimentales de lessivage ont été choisies pour simuler ces événements : conditions oxiques et anoxiques sur des sédiments bruts et d’autres irradiés par rayons gamma. L’utilisation d’eau désionisée a permis de maximiser le processus de relargage. Deux types de sédiments, issus de contextes différents, ont été sélectionnés : le barrage de Villerest (France) et la rivière Xiang (Chine). Des expériences à long terme (30 jours) ont permis d’identifier la dégradation de la matière organique, l’activité microbienne et l’altération (voire la dissolution) de phases porteuses d’ETM comme principaux facteurs de contrôle. L’importance de l’activité microbienne n’a pas pu être quantifiée puisque l’irradiation n’a pas stérilisé totalement les sédiments. Enfin, l’impact de tels évènements parait très limité puisque moins de 1% des ETM contenus dans les sédiments ont été libérésIn aquatic systems, most of trace metals (TM) are buried in sediments and then can be released according to chemical conditions and microbial activity occurring at the sediment-water interface. The aim of this study was to assess the impact of resuspension events (flood or maintenance operations for dam reservoir) on the mobility of some TM. Different batch experiment conditions were chosen to mimic those events: under oxic and anoxic conditions on raw sediments and on gamma-irradiated ones (“sterilized” one). The use of deionized water allowed maximizing the release process. Two sediment types issued from different contexts were selected: the Villerest dam reservoir (France) and the Xiang River (China). Long term experiments (30-day long) allowed identifying that organic matter degradation, microbial activity and alteration/dissolution of trace metal bearing phases were the main controlling factors. The gamma-irradiation did not sterilize sediments but only limited aerobic bacteria and enhanced anaerobic activity. The impact of such 24h resuspension event on reservoir waters and downstream biota is very limited as less than 1% of trace elements was released
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Zhou, Hai Yun. "Evaluation of organochlorines and heavy metals in the Pearl River Delta and Hong Kong, with emphasis on bioaccumulation in freshwater fish." HKBU Institutional Repository, 1999. http://repository.hkbu.edu.hk/etd_ra/207.
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Wang, Fang. "Ecotoxicological quality assessment of sediments in Guiyu, an electronic waste disposal site in Southeast China." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/809.
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Carton, Julie. "The role of fine sediment as a vector for contaminant transport in fluvial systems : a case study of heavy metals in the River Aire, Yorkshire, UK." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324750.
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D'Sa, Jean Vanita. "Rapid Removal of Toxicity of Acid Mine Drainage Contaminated Sediments in a Clean Stream: Relative Contribution of Acidity Vs Metals." Ohio University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1087840199.
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Torres, Ronaldo José. "Efeitos da dragagem sobre a qualidade de sedimentos contaminados do canal do porto de Santos : biodisponibilidade e toxicidade de metais e compostos orgânicos persistentes." Universidade Federal de São Carlos, 2007. https://repositorio.ufscar.br/handle/ufscar/6128.
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Contaminated sediments is a worldwide problem, and mobilization of contaminants is one of the most critical issue in environmental risk assessment when dredging projects are concerned. Considering this, we decided to investigate if and how toxic metals and persistent organic compounds such as PAH and PCB are mobilized during dredging operations in the Port of Santos channel (São Paulo State, SE Brazil) in an attempt to assess changes in bioavailability and toxicity of those contaminants. Samples were collected in the dredging site before dredging, in the dredge s hopper (suction hopper dredge) and in the disposal site and its surroundings. Metals and persistent organic compounds were extracted from sediment samples according to USEPA methods for environmental samples. Ecotoxicological assessment was done on bulk sediment samples and in its pore water and elutriate. Results have shown that bulk sediments from the dredging sites are moderately contaminated with As, Pb and Zn and most severely with Hg, as well as had relatively high PCBs and PAHs concentrations (0,8 mg kg-1 for total Hg and 470 μg kg-1 for total PAHs, for example). These results have also shown a 50% increase in the total PAHs concentration in total suspended solids of the water samples collected inside of the dredge s hopper (679 μg kg-1 total PAHs on the total suspended solids against 479 μg kg-1 on bulk sediments from the channel collected on Alemoa terminal). This finding is of great concern as these data refer to the dredge overflow water which is pumped back to the ecosystem during dredging operations. Toxicity tests done with bulk sediment using the amphipod Tiburonella viscana did not show any toxicity, but the tests with the larvae of the sea urchin Lytechinus variegatus showed toxicity to the interstitial waters and elutriates of samples collected in the channel (dredging site), disposal site (sea site) and dredge´s hopper. In this study we also compared the obtained results to the widely used sediment quality guidelines (ERL and ERM), and to a sediment quality assessment scheme (based on various lines of evidence), as well as, to the Brazilian National Council for the Environment resolution called CONAMA 344/04. It can be seen in the results obtained in microcosm experiments (laboratory) that some organic compounds, mainly fluoranthene and pyrene, can be released from the sediments to the water. Such release was detected in the analysis of these compounds adsorbed in semi-permeable membranes (SPMDs) used in these tests. We hope that the results of this study will be used in the future to support a better planning of management strategies in dredging operations and sediment disposal in marine environment in Brazil.
Este trabalho visa avaliar os impactos causados pelas atividades de dragagem sobre a qualidade dos sedimentos do canal do Porto de Santos, priorizando o levantamento de dados tendo em vista o entendimento das alterações da partição, biodisponibilidade e toxicidade de contaminantes decorrentes destas atividades. Esta avaliação foi realizada através da determinação da concentração de contaminantes químicos (nutrientes, metais e compostos orgânicos xenobióticos) dos sedimentos (fração fracamente ligada), de suas águas intersticiais e elutriatos, e também, através de uma avaliação ecotoxicológica. As amostras foram coletadas nos sítios de dragagem (previamente à mesma) em cinco pontos do canal (dois próximos ao Terminal da Alemoa, dois no Terminal de Conteineres e um em frente ao Armazém 23), na draga após a dragagem (no interior da cisterna) e no sítio de disposição (antes e após a abertura da cisterna do navio). Os metais e os compostos orgânicos foram extraídos de acordo com os métodos da USEPA com extração por ácido nítrico e peróxido de hidrogênio para metais e ácido nítrico, sulfúrico e permanganato de potássio para mercúrio e com mistura hexano/acetona em ultra-som para compostos orgânicos. Os metais são determinados por espectrofotometria de absorção atômica e os compostos orgânicos são determinados por cromatografia gasosa acoplada a espectrometria de massas. Os resultados obtidos foram comparados a diferentes valores-guia de qualidade de sedimentos e aos critérios numéricos para a avaliação e classificação da qualidade de sedimentos a serem dragados que constam da Resolução CONAMA Nº 344/04. A partir dos resultados alcançados, foi possível constatar a contaminação do sítio de estudo por compostos orgânicos (como PAH e n-alcanos) e por metais (como Cd, Cr, Cu, Ni, Pb e Zn) e pelo semimetal As em níveis moderados e uma contaminação mais acentuada por Hg. As concentrações dos sedimentos do terminal da Alemoa estiveram na ordem de 470 μg kg-1 para PAH totais e 0,8 mg kg-1 para Hg total, sendo que este último violou os níveis 1 e 2 da Resolução CONAMA Nº 344/04. Nos testes de toxicidade, embora nos testes realizados com anfípodos (Tiburonella viscana), o sedimento integral em si não tenha se mostrado tóxico, suas águas intersticiais e elutriatos mostraram-se tóxicas nos testes realizados com larvas de ouriços (Lytechinus variegatus). Pôde-se, também, observar que o material particulado suspenso, coletado no interior da cisterna da draga, apresenta uma concentração maior destes elementos comparando-se ao sedimento original (679 μg kg-1 de PAH totais nos sólidos totais suspensos contra 479 μg kg-1 nos sedimentos do canal coletados no terminal da Alemoa) e, como durante a dragagem este material retorna ao ambiente através do overflow (eliminação da água excedente da cisterna da draga), é de se esperar um impacto negativo causado pelo retorno desses particulados e contaminantes ao ambiente. A partir dos experimentos de microcosmos desenvolvidos, pôde-se constatar que alguns compostos orgânicos, em especial fluoranteno e pireno, são liberados do sedimento para a coluna d'água, fato constatado pelo aumento da concentração desses compostos adsorvidos nas membranas semi-permeáveis (SPMDs) empregadas para tal fim, técnica esta, que poderia ser empregada em programas de monitoramento de atividades de dragagem. Espera-se que, de alguma forma, este trabalho possa contribuir, no futuro, a um melhor planejamento de estratégias de manejo e de tomada de ações para operações de dragagem e disposição de material dragado no ambiente marinho no Brasil.
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Cervi, Eduardo Cimino. "Avaliação da qualidade de sedimentos do reservatório Billings-SP por meio de linhas de evidências químicas e ecotoxicológicas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-29052017-155244/.
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O Complexo Billings é o maior reservatório de água da Região Metropolitana de São Paulo. Devido a sua importância estratégica e à degradação da qualidade de suas águas e sedimentos, a represa foi e continua sendo alvo de muitas pesquisas. No entanto, os valores-guia da qualidade de sedimentos (VGQS) adotados pelas normas nacionais vigentes, usualmente aplicados nestes estudos, baseiam-se na abordagem canadense Threshold Effect Level/Probable Effect Level (TEL/PEL), e sua interpretação quanto aos efeitos tóxicos podem divergir dos países que as originaram. O objetivo deste trabalho foi avaliar o potencial tóxico de contaminantes orgânicos e inorgânicos na água e nos sedimentos do reservatório Billings por meio da utilização de diferentes VGQS empíricos e teóricos e ensaios ecotoxicológicos. Uma abordagem multi-tarefas foi conduzida através de avaliações em campo e em laboratório envolvendo extensas caracterizações químicas, físicas e toxicológicas ao longo de dez pontos do reservatório. Em cada local, os parâmetros de qualidade da água superficial foram monitorados in situ. Amostras de sedimento integral, água intersticial e superficial foram coletadas para a avaliação das propriedades físicas e químicas nestes locais, como granulometria e carbono orgânico total (COT). Os teores de sulfetos volatilizáveis por acidificação (SVA) e os metais extraídos simultaneamente (MES) foram obtidos nas amostras de sedimento integral, assim como as concentrações totais de metais (Cd, Cr, Cu, Fe, Mn, Ni, Pb e Zn) e contaminantes orgânicos (pesticidas organoclorados e hidrocarbonetos aromáticos polinucleares). Os contaminantes foram então comparados a diferentes linhas de evidências (LDE), dentre elas VGQS empíricos (TEL/PEL, LEL/SEL e VRR), VGQS baseados na teoria do Equilíbrio de Partição (EqP) e ensaios ecotoxicológicos com as espécies Daphnia magna e Hyalella azteca em água superficial e sedimento integral, respectivamente. As concentrações de metais nas águas superficial e intersticial do reservatório foram relativamente baixas e ausentes de efeitos crônicos ou agudos pelos ensaios ecotoxicológicos. Os teores de SVA foram superiores aos de MES quando normatizados pela fração COT. Embora a LDE baseada em EqP tenha sugerido a ausência de toxicidade nos sedimentos do reservatório Billings, a mesma ocorreu nos pontos Braço do Rio Grande e Barragem de Pedreira. Os resultados dos ensaios ecotoxicológicos demonstraram efeitos agudos para Hyalella azteca, com sobrevivência dos organismos de 32,5 ± 6,57% e 45 ± 5,77% nos pontos Braço do Rio Grande e Barragem de Pedreira, respectivamente. Efeitos crônicos também foram observados para a espécie H. azteca em ambos os pontos. Os valores de biomassa individuais dos anfípodas foram afetadas quando comparadas ao Controle (0,072 ± 0,01 mg), com valores de 0,032 ± 0,01 mg e 0,031 ± 0,01 mg no Braço do Rio Grande e Barragem de Pedreira, respectivamente. A utilização dos VGQS empíricos TEL/PEL e os Valores de Referência Regionais demonstraram ser eficazes para predição de efeitos tóxicos, visto que as concentrações dos metais Cu, Cr, Ni, e Zn presentes nos sedimentos superaram o limiar PEL em vários pontos do reservatório, indicando uma alta probabilidade de efeitos adversos à biota, comprovada pelos ensaios ecotoxicológicos. As concentrações dos pesticidas organoclorados mirex e DDT encontram-se acima de TEL, enquanto o DDE, mais persistente, demonstrou uma alta probabilidade de ocorrência de efeitos tóxicos (acima de PEL). Embora o EqP não tenha sido eficaz na predição dos efeitos tóxicos, foi imprescindível para compreender a dinâmica dos metais no reservatório, visto que os elevados teores de sulfetos e COT demonstram ser os responsáveis pelo equilíbrio dos metais neste ambiente. Dessa forma, a combinação de VGQS empíricos e teóricos pode - de maneira não regulatória - ser considerada uma solução efetiva e de baixo-custo para a tomada de decisão sobre locais passivos de contaminação.The Billings Complex is the largest water-storage facility in the São Paulo Metropolitan Region. Due to its strategic importance and the deterioration in its water quality over time, the Billings reservoir was and remains subject of many researches. However, the sediment quality guidelines (SQGs) adopted in Brazil and usually applied in these studies are based on the Canadian Threshold Effect Level/Probable Effect Level (TEL/PEL) and may not suitably predict ecotoxicological effects. The aim of this study was to evaluate the toxicity of organic and inorganic compounds in the overlying water, pore water and bedded sediments of the Billings reservoir through several SQGs and toxicological tests. A laboratory and field assessment was conducted involving extensive physical, chemical, and toxicological characterizations within ten stations of the Billings reservoir. At each sampling station, water quality parameters (pH, redox, DO, conductivity, turbidity, and temperature) were measured in depth (intervals of 1 meter). Bedded surface sediment, sediment pore water, and overlying water were collected to assess the physical and chemical properties at these sites, such as particle size and total organic carbon (TOC). Sediment samples were analyzed for acid volatile sulfides (AVS) and simultaneously extractable metals (SEM), total metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and organic contaminants (organochlorine pesticides and semivolatile organic compounds). Empirical (TEL/PEL, RRV, and LEL/SEL) and mechanistic (AVS/SEM) SQGs approaches were applied and compared with 10-d toxicity tests with Daphnia magna and Hyalella azteca for overlying water and bedded sediment, respectively. Metals in the overlying and pore water were at a relatively low concentrations and absent of chronic or acute effects. AVS concentrations was greater then SEM in every station of the reservoir, therefore suggesting the absence of toxicity. However, Hyalella azteca post-exposure survival was affected in both Rio Grande branch and Pedreira Dam stations (32,5 ± 6,57% and 45 ± 5,77%, respectively). Relative growth rates were also affected in both Rio Grande branch and Pedreira Dam stations (0,032 ± 0,01 mg and 0,031 ± 0,01 mg) when compared to Control (0,072 ± 0,01 mg). Empirical (TEL/PEL, RRV, and LEL/SEL) guidelines were more suitable for toxicity prediction. Several stations exhibit metal concentrations for Cu, Cr, Ni, and Zn higher than the Canadian PEL adopted in Brazil. Organic compounds such as mirex and DDT were above TEL. Persistent DDT metabolite p,p\'-DDE were above PEL in both Rio Grande branch and Pedreira Dam stations. Although EqP was not suitable for toxicity prediction, it was important for understanding the role of sulfides and TOC for metal contamination in the reservoir. Therefore, the adoption of both empirically and mechanistic SQGs for sediment quality assessments can provide a more accurate and low cost alternative for sediment management decisions.
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Gutsalenko, Tetiana. "Solidification/Stabilization of harbor sediments using GGBS-based hydraulic binders." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST058.
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L’accumulation des sédiments sur les littoraux se créée à partir des processus physiques, chimiques et biologiques. Les activités anthropiques participent fortement à l’augmentation du taux de sédimentation. Elles sont également une source de contaminants chimiques notamment des métaux lourds qui sont un risque pour l’environnement aquatique et la santé publique. Afin de dégager les voies de navigation, des opérations régulières de dragage dans les grands ports industriels sont réalisées et produisent autour de 100-200 millions m3/an de déblais de dragage contaminés. Il peut donc être nécessaire de traiter ces sédiments, notamment par Solidification/Stabilisation (S/S).L’étude actuelle s’intéresse plus particulièrement à la valorisation de sédiments provenant de Dublin (Irlande) pour une réutilisation potentielle comme matériaux de remplissage dans le cadre du projet du bassin d’Alexandra (PBA). Les sédiments contaminés en métaux lourds, doivent être stabilisés par la technologie de S/S au moyen d’un liant hydraulique. Cette recherche propose l’utilisation du laitier de haut-fourneau (LHF) comme agent liant alternatif au ciment Portland largement utilisé. L’objectif de cette étude est donc de développer un liant à base de LHF pour fournir un comportement mécanique requis pour une utilisation ultérieure du nouveau matériau en s’intéressant à comprendre les mécanismes ayant un rôle dans la solidification du sédiment traité mais également la stabilisation des métaux lourds.Les sédiments traités par liants hydrauliques à base de LHF ont fait l’objet d’un suivi de la résistance à la compression en comparaison à des sédiments traités par liant à base d’OPC. Le traitement au LHF activé par une petite quantité d’OPC a démontré une augmentation significative de la résistance au fil du temps, tandis que celle du traitement à l’OPC a montré une dégradation des propriétés mécaniques. Dans le but d’expliquer les résultats obtenus, des études de suivi de la formation des hydrates, de retrait et de microstructure ont été menées. En outre, les interactions avec les différents liants de la fraction argileuse, de la matière organique et des métaux lourds, qui constituent les sédiments de Dublin étudiés, ont été évaluées séparément et au moyen de milieux simplifiés. La thèse met en évidence par l’étude de l’impact de la fraction argileuse que le phénomène de dispersion/floculation est un des principaux mécanismes responsables de l’évolution des propriétés mécaniques du sédiment traité. L’étude des interactions entre la matière organique avec les liants montre une dégradation de certains composés organiques au cours de temps et ce d’autant plus avec l’OPC. Enfin, certains métaux lourds impactent par un retard ou une accélération significative de l’hydratation des liants considérés.La mobilité des métaux lourds du sédiment de Dublin après le traitement S/S a été examiné en utilisant un test de lixiviation standardisé. L’augmentation de la proportion de LHF induit une diminution de la quantité de métaux lourds lixiviés. En effet, l’analyse par extraction séquentielle a permis de suivre la distribution des métaux lourds parmi les principales fractions de sédiments avant et après traitement. L’emploi de LHF permet une réduction de la migration des métaux dans la fraction la moins stable après le traitement S/S. Dans le but d’explorer les mécanismes de stabilisation, en particulier les changements dans l’environnement chimique des métaux lourds (état d’oxydation/numéro de coordination etc.), la spectroscopie d’absorption aux rayons X s’est avérée être une technique pertinente. Ainsi, il a été observé que l'environnement chimique du Cu et du Zn n'a pas été modifié dans le cas des liants à forte teneur en LHFThe accumulation of sediment particles in coastal areas arises from physical, chemical, and biological processes. Anthropogenic activities dramatically increase the sedimentation rate. Sediments may contain chemical contaminants including heavy metals (HM) and are consequently a risk to the aquatic environment and human health. Regular dredging of important shipping lanes in large industrial ports is required and this produces around 100-200 million m3 of contaminated dredged material per year. Therefore, proper treatment of the contaminated sediments is necessary, with Solidification/Stabilization (S/S) remediation technology at the forefront.The current study is specifically interested in the treatment of sediment originating in the Dublin Port for its potential reuse as a fill material for the Alexandra Basin Redevelopment Project. The sediment is contaminated with heavy metals and must be stabilized by S/S technology using a hydraulic binder. This research proposes the use of ground granulated blast furnace slag (GGBS) as an alternative binding agent to the widely used Portland cement. The objective of this study is therefore to develop an appropriate GGBS-based binder to provide the required engineering properties for further reuse of the newly formed solidified material by focusing on understanding the mechanisms having a role in the solidification of the treated sediment, but also in the stabilization of heavy metals.The compressive strength of the range of GGBS-based formulations was assessed with the UCS test and compared to the OPC-based treatment. GGBS activated by a small amount of Portland cement demonstrated a considerable increase in strength over time while that of only OPC showed a degradation of mechanical properties. To explain the obtained results, XRD, shrinkage, and microstructure investigations were conducted. In addition, the interaction of the binders with the clay fraction, organic matter, and trace metals, which were found in the studied Dublin sediments, was assessed separately through simplified models. The study of the clay fraction highlights that the phenomenon of dispersion/flocculation is one of the main mechanisms responsible for the evolution of the mechanical properties of the treated sediment. The findings from the organic matter study show a decrease of the content of some organic compounds over time, with the greatest impact observed via treatment with Portland cement. Moreover, certain heavy metals have an impact by delaying or significantly accelerating the hydration of the considered binders.The mobility of heavy metals in the treated Dublin sediment was examined using a standard leaching test. It was found that with an increase in the proportion of GGBS, the amount of leached HM decreased. Moreover, sequential extraction analysis was shown to be effective in studying the distribution of trace metals among the main sediment fractions before and after treatment. The use of GGBS as a stabilizing agent allows a decrease of the migration of heavy metals into the less stable fraction after S/S treatment. X-ray Adsorption Spectroscopy (XAS) was demonstrated to be a useful technique to explore the stabilization mechanisms, in particular changes in the chemical environment of HM (oxidation state, coordination number, etc.). It was observed that the chemical environment of Cu and Zn was not modified in the case of binders with high GGBS content
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Lai, Mei-yee, and 黎美兒. "Fractionation, mobilization and bioaccumulation of heavy metals and mineralogical characteristics of the Mai Po Inner Deep Bay mudflat." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29980069.
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Leung, Siu Ying. "Accumulation of DDTs, heavy metals and PBDEs in fish collected from fish ponds and mariculture zones of the Pearl River Delta, China." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/880.
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Redfern, Farran M. "Heavy metal contamination from landfills in coastal marine sediments, Kiribati and New Zealand /." 2006. http://adt.waikato.ac.nz/public/adt-uow20060501.141345/index.html.
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"Heavy metal accumulation and biomarkers in environmental monitoring of contaminated coastal sediments." 2005. http://library.cuhk.edu.hk/record=b5892606.
Full textAbstract:
Tang Wai Lun.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 199-220).
Abstracts in English and Chinese.
Abstract --- p.ii
摘要 --- p.iv
Acknowledgements --- p.vi
Table of contents --- p.vii
List of Abbreviations --- p.xi
List of Tables --- p.xii
List of Figures --- p.xv
Chapter Chapter One --- Literature Review --- p.1
Chapter 1.1 --- Marine pollution in Hong Kong --- p.1
Chapter 1.2 --- Contamination of sediments --- p.3
Chapter 1.2.1 --- Metals contamination in coastal sediments in Hong Kong --- p.4
Chapter 1.2.2 --- Other contaminants in sediments --- p.7
Chapter 1.3 --- Sediment toxicity assessment --- p.9
Chapter 1.4 --- Fish as examples for the measurement of biological responses to contaminants --- p.9
Chapter 1.5 --- Biomarkers for toxicity assessment --- p.11
Chapter 1.5.1 --- Metallothionein (MT) --- p.11
Chapter 1.5.2 --- Cytochrome P450 1A (CYP1A) --- p.13
Chapter 1.5.3 --- Vitellogenin (Vtg) --- p.13
Chapter 1.5.4 --- Enzyme biomarkers: Alanine transaminase (ALT); aspartate transaminase (AST) and creatine kinase (CK) --- p.14
Chapter 1.5.5 --- DNA damage detected by the comet assay --- p.16
Chapter 1.6 --- Multi biomarkers for sediment toxicity assessments --- p.16
Chapter 1.7 --- Objectives --- p.16
Chapter Chapter Two --- "Concentrations of Heavy Metals and Trace Organics in Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.18
Chapter 2.1 --- Introduction --- p.18
Chapter 2.2 --- Materials and Methods --- p.19
Chapter 2.2.1 --- Sediment collection --- p.19
Chapter 2.2.2 --- Treatment of sediment samples --- p.21
Chapter 2.2.3 --- Acid wash of apparatus --- p.21
Chapter 2.2.4 --- Acid digestion of sediment sample --- p.21
Chapter 2.2.5 --- Sequential extraction of heavy metals in sediment samples --- p.22
Chapter 2.2.6 --- Heavy metals measurement --- p.23
Chapter 2.2.7 --- Trace organic measurement in sediments --- p.24
Chapter 2.2.8 --- Statistical Analysis --- p.24
Chapter 2.3 --- Results --- p.25
Chapter 2.3.1 --- Concentrations of total Metals in sediments --- p.25
Chapter 2.3.2 --- Speciation of metals in sediments --- p.27
Chapter 2.3.3 --- Metal abundance in different fractions of sediment --- p.33
Chapter 2.3.4 --- Concentrations of trace organic in sediments --- p.33
Chapter 2.3.5 --- Results summary --- p.36
Chapter 2.4 --- Discussion --- p.36
Chapter 2.4.1 --- Comparison with international standards --- p.38
Chapter 2.4.2 --- Comparison with international studies of coastal sediments --- p.39
Chapter 2.4.3 --- Comparison of the present study with other studies concerning Hong Kong coastal sediments --- p.45
Chapter Chapter Three --- "Heavy Metals Accumulation in Tissues of Tilapia Exposed to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour, and Lai Chi Wo" --- p.51
Chapter 3.1 --- Introduction --- p.51
Chapter 3.2 --- Materials and Methods --- p.52
Chapter 3.2.1 --- Collection and treatment of coastal sediments --- p.52
Chapter 3.2.2 --- Sediment exposure tests with Tilapia --- p.53
Chapter 3.2.3 --- Dissection of fish samples --- p.54
Chapter 3.2.4 --- Acid digestion of fish samples --- p.54
Chapter 3.2.5 --- Statistical Analysis --- p.55
Chapter 3.3 --- Results --- p.55
Chapter 3.3.1 --- Metal accumulation --- p.55
Chapter 3.3.2 --- "Dose, duration and source of sediments affecting metals uptake" --- p.95
Chapter 3.3.3 --- Results summary --- p.99
Chapter 3.4 --- Discussion --- p.99
Chapter 3.4.1 --- Site comparison --- p.99
Chapter 3.4.2 --- Comparison with other studies --- p.100
Chapter 3.4.3 --- Safety limits --- p.112
Chapter Chapter Four --- "Expression of Biomarker Genes (MT, CYP1 A, Vtg) in Tissues of Male Tilapia After Eexposure to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.115
Chapter 4.1 --- Introduction --- p.115
Chapter 4.2 --- Materials and Methods --- p.116
Chapter 4.2.1 --- Sample collection --- p.116
Chapter 4.2.2 --- Preparation of apparatus --- p.117
Chapter 4.2.3 --- mRNA expression analysis --- p.117
Chapter 4.2.3.1 --- Isolation of RNA --- p.117
Chapter 4.2.3.2 --- Reverse transcription --- p.118
Chapter 4.2.3.3 --- Real time PCR --- p.118
Chapter 4.2.4 --- Vitellogenin (Vtg) --- p.120
Chapter 4.2.5 --- Statistics analysis --- p.121
Chapter 4.3 --- Results --- p.121
Chapter 4.3.1 --- MT mRNA expression in tissues of male Tilapia exposed to sediments --- p.121
Chapter 4.3.2 --- CYP1A mRNA expression in tissues of male Tilapia exposed to sediments --- p.129
Chapter 4.3.3 --- Vtg expression in tissues of male Tilapia exposed to sediments --- p.137
Chapter 4.3.4 --- Dose and time dependent relationships --- p.137
Chapter 4.3.5 --- Results summary --- p.137
Chapter 4.4 --- Discussion --- p.142
Chapter 4.4.1 --- Correlation of MT and CYP1A expression with metals uptake in gills and liver --- p.142
Chapter 4.4.2 --- MT as a biomarker of metals exposure --- p.144
Chapter 4.4.3 --- CYP1A as a biomarker of trace organics exposure --- p.145
Chapter 4.4.4 --- Real-time PCR --- p.147
Chapter 4.4.5 --- Vtg as a biomarker of xenoestrogen exposure --- p.147
Chapter Chapter Five --- "Expression of Enzyme Biomarkers (ALT, AST and CK) in Tissues of Male Tilapia After Exposure to Coastal Sediments Collected From Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.149
Chapter 5.1 --- Introduction --- p.149
Chapter 5.2 --- Materials and Methods --- p.150
Chapter 5.2.1 --- Samples collection --- p.150
Chapter 5.2.2 --- Alanine transaminase (ALT) and Aspartate transaminase (AST) --- p.151
Chapter 5.2.3 --- Creatine kinase (CK) --- p.152
Chapter 5.2.4 --- Statistical analysis --- p.153
Chapter 5.3 --- Results --- p.153
Chapter 5.3.1 --- ALT --- p.153
Chapter 5.3.2 --- AST --- p.157
Chapter 5.3.3 --- CK in gills --- p.157
Chapter 5.3.4 --- CK in muscle --- p.164
Chapter 5.3.5 --- "Dose, duration and source of sediments affecting metals uptake" --- p.164
Chapter 5.3.6 --- Results summary --- p.169
Chapter 5.4 --- Discussion --- p.169
Chapter Chapter Six --- "DNA Damage in Liver of Male Tilapia After Exposure to Coastal Sediments Collected from Victoria Harbour, Deep Bay, Tolo Harbour and Lai Chi Wo" --- p.174
Chapter 6.1 --- Introduction --- p.174
Chapter 6.2 --- Materials and Methods --- p.176
Chapter 6.2.1 --- Samples collection --- p.176
Chapter 6.2.2 --- Tissue Preparation --- p.176
Chapter 6.2.3 --- Single Cell Gel Electrophoresis (Comet) Assay --- p.176
Chapter 6.2.4 --- Image analysis --- p.177
Chapter 6.2.5 --- Statistical analysis --- p.178
Chapter 6.3 --- Results --- p.180
Chapter 6.4 --- Discussion --- p.187
Chapter Chapter Seven --- General Discussion and Conclusion --- p.190
Chapter 7.1 --- General discussion --- p.190
Chapter 7.2 --- Conclusion --- p.198
References --- p.199
Appendix --- p.221
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SYU, SYUAN-YAO, and 許炫堯. "Removal of Heavy Metal from Contaminated Harbor Sediments by Acid Washing." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/76302091652940310204.
Full textAbstract:
碩士國立高雄海洋科技大學
海洋環境工程研究所
105
This study used the acid washing to remove the heavy metal in the contaminated sediments at three estuaries of Kaohsiung Harbor (Jen-Gen River, Canon River, and Salt River). Effects of reaction time (0−300 min), liquid/solid (5−25), types and concentrations of acids on the removal efficiency of heavy metals (copper (Cu), zinc (Zn), nickel (Ni), cadmium (Cd), chromium (Cr), and lead (Pb)) were investigated. In order the sequence extraction analysis of sediments was carried out to understand the change of the binding form of heavy metals before and after acid washing. The Five binding forms were divided into exchangeable, carbonate, Fe-Mn oxide, organic, and residual fractions. The extraction amounts of metals approached equilibrium values in 15 min. The removal rate of heavy metals increased with an increase in insignificantly liquid/solid ratio and acid concentration. Yet, the removal rate increased for the liquid/solid ratio higher than 10 and the acid concentration more than 0.5 M. The removal rates of Zn (80.1−83.7%), Ni (27.6−30.9%), Cr (20.7−23.9%), and Cd (97.2−98.8%) were similar for using three types of acid (HCl, HNO3, CA) washig, whereas the removal rates of Cu and Pb by HCl (65.3% and 79.4%) and HNO3 washing (65.8% and 76.4%) were more effective than those by CA washing (46.0% and 51.4%). Results showed that the optimal removal efficiencies of Cu, Zn, Ni, Cd, Cr, and Pb in the sediment from Jen-Gen River were 78, 75, 33, 100, 21, and 85%, from Canon River were 57, 92, 22, 100, 26, and 72%, and from Salt River were 61, 81, 37, 96, 25, and 81%, respectively, using 0.5 M HCl, liquid/solid ratio of 10, and washing time of 15 min. The removal efficiency of heavy metals in the carbonate bond form after acid washing was obrionly high (90.1−100%). However, most metals were found to slightly increase in the highly- mobile exchangeable fraction after washing, such as Cu, Zn, Ni, and Cr. The finding may be attributable to the release of heavy metal from the re-adsorption of strong binding fraction to the exchangeable fraction on the surface of particles. Moreover, the removal rates of metals megatively correlate with the guantities of metals in residual fraction. The metals concentration in the treated sediment can be below the soil pollution monitoring standards using the optimal parameters of acid washing except Cr. The treated sediment can be used to reclamation land and other purposes. The results of this study can provide a reference for sediment remediation using acid washing in the future.
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Edwards, Ellen McLain Kostka Joel E. "Characterization of metal-reducing microbial communities from acidic subsurface sediments contaminated with uranium(VI)." Diss., 2005. http://etd.lib.fsu.edu/theses/available/etd-12222004-153409.
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Thesis (Ph. D.)--Florida State University, 2005.Advisor: Dr. Joel E. Kostka, Florida State University, College of Arts and Sciences, Dept. of Oceanography. Title and description from dissertation home page (viewed June 22, 2005). Document formatted into pages; contains xii, 94 pages. Includes bibliographical references.
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Liu, Yan-Ting, and 劉彥廷. "Rapid vitrification of sediments contaminated by heavy metals." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/57393573898572003744.
Full textAbstract:
碩士國立中興大學
環境工程學系所
105
Nowadays, with the rapid development of industry and commerce, many pollutants enter the river due to improper discharge, which has caused serious pollution of rvier sediment. The most common contaminants of sediment are heavy metals. Excessive exposure and absorption of heavy metals will accumulate in the body and cause adverse health effects. In Taiwan, due to the frequent flooding events by typhoons and torrent rains, shallow depth, and large hydraulic gradient, current sediment remediation technologies may not be applicable in Taiwan. Therefore, this research will focus on stabilizing heavy metals in sediment by vitrification using induction heating. The use of high-frequency electromagnetic induction equipment for heating can reach 1000℃ in a short period of time. . The results showed that the concentrations of chromium, copper, nickel, and zinc were higher than the upper limit of Sediment Quality Guideline set by Taiwan EPA. It was found that the better additive（sodium carbonate and calcium carbonate） and continuously holding time was 90 seconds after reach the designated temperature. We also found that the results of the rise of time with the metal concentration decreased. Then Taguchi method was applied to test the impact of different controlling factors. The stabilization at temperature 1600 ℃, 0% moisture content, high content of additives, and a 90-seconds holding time, resulted in more than 90% can passed on regulated standards. Furthermore, the best conditions was defined as 1600 ℃, 30% moisture, medium additives, 90 seconds holding time. The experimental results of different metals showed that the temperature and the amount of additives (salt content) are the most influential factors for this induction heating technology. All the results showed that induction heating stabilization of contaminant in sediments is highly feasible..
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Lu, Hsiao-Fang, and 盧曉芳. "Effects of biosurfactants on the phytoremediation of metal-contaminated sediment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/p23p3a.
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Lu, Hsiao-Fang, and 盧曉芳(紙本延後至1090121止公開). "Effects of biosurfactants on the phytoremediation of metal-contaminated sediment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/pemzb6.
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Lin, Kun-Hong, and 林昆宏. "Heavy Metal Removal from Contaminated River Sediment Using Bioleaching Process." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/71081761096641011431.
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碩士國立交通大學
環境工程所
91
Because riverbed sediments act as potential sources of contaminants in aquatic environment, and most of pollutant were polluted by human, industrial and urban waste discharge into river system. The present study in bioleaching costs low of treatment and ease of operation. In order to enhance the sulfur oxidation rate. Sulfur powder, which provides larger surface area for the adsorption of sulfur-oxidizing bacteria. However, sulfur-oxidizing bacteria used only 30-40% of sulfur powder during bioleaching process. The unrecoverable sulfur powder remaining in treated sediments increases the operational costs and causes acidification of the disposal land. Therefore, it is necessary to use recoverable forms of sulfur as substrates for sulfur-oxidizing bacteria in the bioleaching. In this study, the recovered of sulfur pellets on bioleaching of heavy metal from contaminated sediment were investigated. Adding recovered sulfur pellets at the beginning of bioleaching process, in order to increase bioconcentraion in an air-lifting reactor. With times of recovery increased, could accelerate the rates of acidification, sulfate production and metal solubilization. One was change sediment solid content. The results showed that the rate of pH reduction decreased with increasing sediment solid content because of the buffering capacity of sediment solid content. For different solid contents (1-10% (w/w)), 34-74% (w/w) of Ni; 40-84% (w/w) of Mn; 56-99% of Cu; 62-99% of Zn; 21-38% of Pb; 14-49% of Cr were leached from sediments in the bioleaching process. The optimal sediment solid content in the bioleaching was 2% (w/w). Another was change inoculum concentration (0-15% (v/v)), the optimal concentration of inoculum concentration added in the bioleaching was 10% (v/v). When adding 15% (v/v) of inoculum concentration to the bioleaching, inhibition of acidification, sulfate production and metal solubilization were fond. And the recovery of sulfur pellets could reach 90-95%, the results decrease sulfur in the treated sediments.
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Chen, Shen-Yi, and 陳勝一. "Removal of Heavy Metals from Contaminated Sediment by Bioleaching." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/90818207037802146175.
Full textAbstract:
博士國立交通大學
環境工程所
87
The management of contaminated sediments in the aquatic environment is one of the most important environmental issues. In future, the remediation of a contaminated river will be faced with two typical problems-- increasing volumes of dredged materials and high concentrations of toxic substances. The objective of this dissertation is to develop a technique for treatment of the large quantity of metal contaminated sediments in the remediation of contaminated rivers. A bacterial mediated leaching process with a mixed culture of two sulfur-oxidizing bacteria for removal of heavy metals form contaminated sediments was established in this dissertation. The effects of operational parameters on solubilization of metals from sediments were assessed. It was found that continuous growth of two species of thiobacilli resulted in sediment acidification and metal solubilization. Because of higher buffer capacity of sediment, the rate of decline in pH decreased with increasing solids concentration of sediment. The rates of sulfate production of bacteria increased as sediment solids concentrations increased. In the heavy metals of concern, the maximum leaching efficiencies of Pb, Ni and Cr were apparently influenced by sediment solids concentrations. The metal solubilization from sediments appeared to follow a first order reaction related with the sediment solids concentration. In the bioleaching process, elemental sulfur is usually used as the substrate for bacterial growth. Adsorption of bacteria to sulfur particles is the first step for oxidaion of sulfur. The more the concentrations of elemental sulfur, the faster the rates of acid production and metal solubilization. But sulfur concentrations in excess of 5% (w/v) were found to be inhibitory to bacterial activity and metal solubilization in the bioleaching process. The optimum concentration of sulfur fed in the bioleaching process is recognized to be 5% (w/v). A first-order reaction related to sulfur concentration is also used to describe the metal solubilization in this bioleaching process when the sulfur concentration are below 5% (w/v). To prevent the reacidification of treated sediments and to recover the remaining sulfur, the sulfur particles in the form of pastilles and pellets are used as the energy source for thiobacilli in the bioleaching process for replacing sulfur powder. The maximum adsorption obtained from the Langmuir isotherm capacity is applied to calculate the specific surface area of sulfur particle. These results of specific surface areas are significant to interpret the sediment acidification and metal solubilization. The pH reduction and metal solubilization are significantly enhanced while reusing of the recovered sulfur particles. It is very possible to reuse the recovered sulfur particles in the bioleaching, sulfur pastilles especially. Finally, a modified logistic model was successfully developed to estimate the variations of pH in the bioleaching process. Besides, the solubilization of heavy metals from sediments is highly pH-dependent and a non-linear efficiency equation of metal solubilization related to pH value in the bioleaching process was established. Therefore, a more simple and faster method of measuring pH is able to simulating the metal solubilization in the bioleaching process.
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Wu, Chi-Hsien, and 吳紀賢. "Application of air-lift bioreactor for metal bioleaching from contaminated sediment." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/60341862470426423349.
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Liao, Chun-Wei, and 廖鈞暐. "Bioleaching of Metal Contaminated Sediment by Facultative Anaerobic Sulfur Oxidizing Bacteria." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/16613027589800888111.
Full textAbstract:
碩士國立交通大學
環境工程系所
104
Recently, a lot of researchers considered sediments as non-point sources of heavy metals pollution in waterbody. In the future, a large quantity of dredged sediments are going to be treated. Biotechnology can transform these sediments into resources which can replace physico-chemical treatment. Bioleaching (aerobic) is one of the biotechnologies that has been proved can remove or recover heavy metals from minerals and sludge, but only a few researches are using it in sediments. Besides, when bioleaching is operating, the aeration and stirring machine will increase the cost and the acid-mine drainage will become secondary pollution due to the acid production ability of microorganisms. Therefore, we use anaerobic bioleaching for removal of heavy metals from contaminated sediments. The advantages of this technology are that it is widely used for different kind of minerals, it can be operate without aeration and its low acid production are environmental-friendly as well. This research used facultative anaerobic sulfur oxidizing bacteria to operate anaerobic bioleaching in order to find out a best working parameter and evaluate the workability. This experiment used At. ferrooxidans to operate under different initial pH, sulfur dosage concentration, sediment solid dosage concentration, inoculation dosage and scale up from 800 mL to 2 L in order to evaluate the leaching efficiency. The result revealed that the best working condition is under initial pH 2, 5 g/L of sulfur dosage concentration, 1% of sediment solid dosage, 20% of inoculation dosage, and the leaching efficiency is increased when scale up. While T. denitrificans is used to operate under different initial pH, sulfur dosage concentration and sediment solid dosage concentration. The result revealed that the best working condition for metal leaching is under initial pH 4, 7 g/L of sulfur dosage concentration, and 1% of sediment solid dosage.Although this microorganism able to grow much more successful under initial pH 6, 1 g/L of sulfur dosage concentration, 7% of sediment solid dosage. Initial sediment is combine with heavy meatals mainly by carbonate, and the kind of boundary is the most important factor to meatal leaching. Heavy meatals combined with Fe/Mn oxides is the secondary.
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Wu, Shian-Chang, and 吳憲昌. "The Influence of Fluoride on Metal Mobilization from Contaminated River Sediment." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/51671093366961777483.
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碩士國立交通大學
環境工程系所
94
The semiconductor industry in Taiwan was the 4th of the world. It was also the most important industry which leaded the Taiwan to High-technology production. The hydrofluoric acid (HF) is a chemical which used to wafer etching and quartz cleaning in semiconductor industry. Fluoride concentration is 1,000-3,500 mg/L found in typical wastewater of local semiconductor industry. In Taiwan the discharge standard of fluoride is 15 mg/L. When the fluoride discharge into the river how the fate it would be and if it would have the potential to damage the environment. The subject above is the aim of our research. The river sediment was a storage which accepted the pollution form various source. The heavy metal was the most important pollutant in river sediment. The heavy metal deposits in the river bottom sediment have a potential to leaching to the aquatic environment again. The releasing probability depends on the binding phases of the heavy metal. The binding phases of heavy metal have five classifications, such as Exchange, Carbonate, Fe/Mn Oxides, Organic and Residaual. The Exchange and Carbonate phases are the most easily releasing again bindings. When the environmental factor changes the metal storages in the two phases will leaching to the aquatic environment. The results of our study find the quantity of Chromium binds to the Exchange and Carbonate phase increase. The Copper shifts to the Carbonate and Organic phase. The Zinc moves to the Carbonate phase. The fluoride does not affect the Nickel and Lead binding phases significantly. On the results of our study deduced that the fluoride would influence the Cr, Cu, Zn to move to the binding phases which have the potential to leach again.
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Chen, Chia-Hung, and 陳佳宏. "Effects of biosurfactants on the metal speciations in the contaminated sediment." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/01464012666229897755.
Full textAbstract:
碩士國立高雄第一科技大學
環境與安全衛生工程研究所
102
Sediments dredged from contaminated rivers usually contain high concentration of heavy metals and thus cannot be disposed of on the lands without any treatment. It is very important to develop the techniques for treatment of the large quantity of dredged sediments in the remediation of contaminated rivers. Due to the various metal speciations in the sediment, it is not reliable to evaluate the ecological effects of contaminated sediment with the total concentration of heavy metals in the sediment. The purposes of this study are to investigate the effects of biosurfactant concentration and sediment solid content on removal efficiency of heavy metal from the sediment extracted by two biosurfactants (saponin and OSA/AMS), and to investigate the variations of metal speciation in the sediment during the biosurfactant extraction experiments. The results showed that the efficiency of metal removal from the sediment increased with increasing biosurfactant concentration and decreasing sediment solid content. The results of response surface methodology indicated that the maximum efficiency of metal removal was achieved at 700 mg/l of saponin with 1-2% (w/v) of sediment solid content, where up to 20%, 50%, and 70% of Cu, Ni and Zn were removed from the sediment. Meanwhile, the operating conditions were recommended to be selected at 800 mg/l of OSA/AMS and 1-2% (w/v) of sediment solid content for maximum efficiency of metal removal (8% of Cu, 36% of Ni and 88% of Zn) from the sediment. It was also found that metals in the mobile fractions (exchangeable, carbonate-bound, and Fe/Mn oxide-bound fractions) were apparently removed by the surfactants during the extraction experiments. On the other hand, metals in the stable fractions (organic matter/sulfide-bound, and residual fractions) did not change very much. Overall, the ecological risks of contaminated sediment were efficiently reduced by the biosurfactants.
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Lin, Yu Chieh, and 林昱傑. "Remediation of heavy metals from contaminated sediments by washing with chelants." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/07662115179715911721.
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碩士國立高雄海洋科技大學
海洋環境工程研究所
105
Abstract This study investigated the operating parameters for removal of heavy metals (Cu, Zn, Ni, Cd, Cr, and Pb) from a contaminated marine sediment, including the type of washing solutions, reaction time, solution concentration, solution pH, and liquid/solid ratio. From the batch chelant extraction studies, the di-sodium salt of ethylenediamine tetraacetate (Na2EDTA) was a more efficient extraction agent for heavy metals compared to the other agents (S,S-ethylene-diaminedisuccinic acid (EDDS), potassium sodium tartrate (PST), maleic acid (MA), and sodium citrate (SC)). The removal efficiencies of Cu, Zn, Ni, Cd, Cr, and Pb were 53%, 80%, 41%, 92%, 27%, and 89%, respectively, at a 0.2 M Na2EDTA washing solution, liquid/solid ratio of 10, and pH 4.0 with 2 hour washing time. The removal of metals depended mainly on the speciation of the metal forms. From the fractional analysis of the heavy metals in contaminated sediment before and after the extraction, it was found that the extracted metals mainly came from the following four fractions, i.e. exchangeable, carbonate, reducible, and oxidizable fractions. Moreover, the results also indicate that the extraction efficiency of metals increased with increasing liquid/solid ratio and concentration of washing solution, while decreased with increasing pH in the range of 3–12. The obtained data are useful to preliminarily evaluate the removal of heavy metals from the contaminated sediments in chelating agents washing approach.
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Huang, Ching-Yao, and 黃敬堯. "Treatment of Heavy Metals from Contaminated Sediment by Anaerobic Bioleaching." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/zbc9zw.
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碩士國立臺北科技大學
環境工程與管理研究所
102
River restoration and improvement for rivers and lakes has become a very important subject for our government authorities. However, we lack the technology and skills needed to handle polluted aquatic sediments. These skills and technologies are critical to handling the remaining sediments after dredging the river. The main objective of this research is to establish and explore an economic and applicable biological treatment technology to anaerobic bioleaching to utilize the Oxidation-reduction ability and the acid forming ability anaerobic sulfur bacteria. Under different experiment circumstances, the affects of each factor are evaluated to find the best environmental parameters for removing heavy metal from polluted sediments. According the research, during the process of anaerobic bioleaching(At. ferrooxidas)different factors such as initial pH level, sulfur concentration additive volume and sediment solids content all have effects of the effectives of heavy metal extraction. Wherein, Zinc and Copper lands in the highest level followed by Nickel and Chromium and Lead have the lowest extraction efficiency. The best initial pH level is between 2 and the best operation value for sulfur concentration additive volume is 5 g L-1. The best value for sediment solids content is 5%. During the process of anaerobic bioleaching sulfur concentration additive(T./Tm. denitrificans), Zinc and Nickel has the highest efficiency of extracting heavy metal from sediments, followed by copper and lead. Chromium displays no extraction value and is the worst in performance for extracting heavy metal from sediments.
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Lee, Ching-Yi, and 李靜怡. "Effects of catalyst on bioleaching of heavy metals from contaminated sediment." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/34975542096519492262.
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碩士國立交通大學
環境工程所
89
Because of the affinity to the environment, low costs of treatment and ease of operation, bioleaching is increasingly paid attention. The reason why it is not commercially applied is that it needs more reaction time than that of chemical reaction. It is necessary to improve electrochemical mechanism for accelerating the leaching of heavy metal. Presently, it is known that adding cation as catalyst of reaction to bioleaching can exchange the metal ion of sulfide in lattice structure and raise ORP for accelerating the electrochemical reaction, consequently promoting rate of heavy metalin the bioleaching process. In this study, the effects of catalyst on bioleaching of heavy metal from contaminated sediment were investigated. Adding ferric and silver ions at the beginning of the bioleaching process, and adding ferric ion when sediment pH reached 3, could accelerate the rates of acidification, sulfate production and metal solubilization. The optimal concentration of silver added in the bioleaching was 15 mg/L. When adding 30 mg/L of silver ion to the bioleaching, inhibition of acidification, sulfate production and metal solubilization were found. The rate and efficiency of metal solubilization from contaminated sediment is in the decreasing order: Cu > Zn > Mn> Ni> Cr > Pb. It was concluded that the kinetics of metal solubilization was catalyzed by addition of silver ion in the bioleaching process. Adding ferric ions at the beginning of reaction was not able to promote the rate of metal solubilization in bioleaching Therefore, it was found that adding silver ion can obtain the better rates of acidification, sulfate production and metal solubilization. In the experiments of adding ferric ion when sediment pH reached 3, the optimal concentration of 1g/L was obtained. It also revealed that adding ferric ions when sediment pH reached 3 would not influence the growth of thionbacillus bacteria during the bioleaching process.
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Alavi, Ali. "Remediation of a heavy metal and PAH-contaminated sediment by a rhamnolipid foam." Thesis, 2011. http://spectrum.library.concordia.ca/35848/1/Alavi_MSc_F2011.pdf.
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Industrial contaminants have long term and sometimes irreversible adverse effects on humans, animals and the ecosystem. As a result attention has been focused on the effects of these contaminants. One of the concerning environmental issues these days is contaminated sediments. The presence of aquatic organisms in sediments makes them important in the well-being and health of these organisms. If sediments become contaminated, they can pose a threat to sediment dwelling habitants and through these microorganism that can be spread even to humans. Nowadays a major concern that government regulators and related industry can face is the protection and investigation of the quality of aquatic sediments. A protection that can be done through different pathways includes remediation.
An investigation was made into evaluating the capability of a rhamnolipid biosurfactant (JBR425) in the form of a foam for treatment of polycyclic aromatic hydrocarbon (PAH) contaminated fresh water sediments that also have elevated levels of Pb, Zn and Ni. Studies commenced by evaluating foam characteristics followed by performing column tests. To do this, dewatered non-dried sediments were put in a column and the biosurfactant was injected in the form of a foam or a liquid solution. The pressure gradient was monitored during flushing tests to avoid possible problems due to high pressure. Foam quality of the rhamnolipid varied between 85% and 99% with stabilities from 15 to 43 min. PAH and metal removal were then evaluated for sediment samples from sector 103 of the Port of Montreal in Montreal, Quebec with different initial concentrations of target contaminants. Among PAHs, pyrene; benz(a)anthracene and chrysene had concentrations above thresholds according to Quebec Sediment Quality Criteria. Highest removal for PAHs was obtained by a 99% quality foam produced by 0.5% rhamnolipid solution after 20 pore volumes. Removal efficiency (due to mobilization) for the biosurfactant foam was 44.6% of pyrene, 30% of benz(a)anthracene and 37.8% of chrysene while total removal efficiency (mobilization + volatilization) for the biosurfactant foam was 56.4% of pyrene, 41.2% of benz(a)anthracene and 45.9% of chrysene. With biosurfactant liquid solution at the same pH as above mentioned foam (pH 6.8), maximum removal (mobilization) was 31.4% of pyrene, 20.5% of benz(a)anthracene and 27% of chrysene. Here no volatilization of PAHs was observed. Deionized water (DI) did not remove any PAH. For metals, highest removal was achieved using 0.5% rhamnolipid foam (99% quality, pH 10.0). These were 53.3% of Ni, 56.8% of Pb and 55.2% of Zn. Removal efficiencies were reduced between 11% - 13% for metals when a 0.5% rhamnolipid solution was used. DI water removed only 16% for both Pb and Ni individually and 17% of Zn at pH 10.0. From these analyses, lower pH (6.8) rhamnolipid showed higher removal efficiencies for PAHs while it was not as successful for metals. As for metals, pH 10 was proven to be the best. It is concluded that, rhamnolipid foam could be a non-toxic and effective method of remediating PAH and heavy metal contaminated soil/sediments. Further efforts will be required to optimize the performance of the foam.
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Kung, Pei-Yi, and 龔佩怡. "Mobilization of heavy metals from binding fractions of contaminated river sediments by bioleaching." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/23577792360921988121.
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碩士嘉南藥理科技大學
環境工程與科學系暨研究所
91
The aim of this study is to explore the mobility of heavy metals from contaminated river sediments by using bioleaching process. Indigenous sulfur- oxidizing bacteria (SOB) enriched from the sediments of Ell-Ren river were used to oxidize the reduced sulfur originally existed in sediments or added to sulfuric acid under controlled operational conditions (including percentage of inoculum, percentage of substrate added, total solid content and temperature), which resulted in the mobilization of heavy metals from contaminated sediments. In addition, the changes in metal binding characteristics that occur during bioleaching will be explored by using sequential extraction procedure. Due to the production of sulfuric acid from the oxidation of reduced sulfur, the accompanying increase of sulfates, decrease of pH and increase of mobility of total extractable heavy metals were found. Results show that the effect of inoculum adding on pH decrease was more than that of sulfur adding. Higher inoculum percentage could speed up the decrease of pH more during bioleaching. The order of mobilization of total extractable heavy metals (TEHMS) could be shown as following: Zn, Cu, Ni＞Cr ＞Co＞Pb. Except for Co and Ni, the binding fractions of other heavy metals had a consistent variation after bioleaching. It was found that the sediment pH decreased with the increase of substrate concentration while it was lower than 4.80 gS/L. When the concentration of substrate was higher than 4.80 gS/L, the sediment pH could not drop down, which might be due to the inhibition of biochemical reaction. The optimum dosage of substrate for mobilizing TEHM was found at 4.80 gS/L. The total sediment solids (TS) represent the buffer capacity of sediment. Consequently, a lower TS leads to a easier likelihood of overcoming the sediment buffer, and hence a lower sediment pH. Different heavy metals showed different binding behavior at the various TS concentrations. Of three temperatures tested (25.0℃, 37.0℃ and 55.0℃), pH decrease was greatest at 37.0℃, indicating that, after acclimation, bacterial oxidizing activity is greatest at this temperature. Except for Pb, the optimal temperature for solubilization of total extractable heavy metal was 37.0℃. The temperature of bioleaching had a significant impact on changes in partitioning of heavy metals. Transfer of heavy metals between binding fractions was most apparent at 55.0℃ before and after bioleaching.