sediment core Articles
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Determination of PBDEs in Sediment Samples using the SpeedExtractor E-914
Polybrominated diphenyl ethers (PBDEs) are flame retardants used in a myriad of applications and are monitored worldwide because of health concerns. In this application, PBDE congeners were extracted from two sediment samples (certified sample and sediment core from Lake Maggiore) according to EPA method 3545A using the SpeedExtractor E-914 and determined by GC-MS/GC-ECD. The results were ...
By BUCHI
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Early-20th Century Environmental Changes Inferred Using Subfossil Diatoms from a Small Pond on Melville Island, N.W.T., Canadian High Arctic
Diatom-based paleolimnological studies are being increasingly used to track long-term environmental change in arctic regions. Little is known, however, about the direction and nature of such environmental changes in the western Canadian high Arctic. In this study, shifts in diatom assemblages preserved in a 210Pb-dated sediment core collected from a small pond on Melville Island, N.W.T., were ...
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Polychlorinated biphenyls in urban lake sediments from Wuhan, Central China: occurrence, composition, and Sedimentary record
Nine surface sediments and a dated sediment core collected from urban lakes in Wuhan, Central China, were analyzed to investigate the concentrations, occurrence, composition, and depositional fluxes of polychlorinated biphenyls (PCBs). The concentrations of {Sigma}PCB (the sum of 39 congeners) in surface sediments ranged from 0.90 to 46.14 ng g–1 dry weight. Only in Longyang Lake and Nantaizi ...
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Using sediment cores to establish targets for the remediation of aquatic environments
When assigning site-specific restoration targets for deteriorating aquatic systems, it is necessary to have an understanding of the undisturbed or background state of the system. However, the site-specific characteristics of aquatic systems prior to disturbance are mostly unknown, due to the lack of historical water and sediment quality data. This study aims to introduce a method for filling ...
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Use of a novel sediment exposure to determine the effects of triclosan on estuarine benthic communities
Triclosan (5‐chloro‐2‐[2,4‐dichlorophenoxy]phenol) is a relatively new, commonly used antimicrobial compound found in many personal care products. Triclosan is toxic to marine organisms at the micrograms per liter level, can photodegrade to a dioxin, can accumulate in humans, and has been found to be stable in marine sediments for over 30 years. To determine the effects of triclosan on marine ...
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Historical decline and altered congener patterns of polychlorinated dibenzo‐p‐dioxins and dibenzofurans in fish and sediment in response to process changes at a pulp mill discharging into Jackfish Bay, Lake Superior
Improved regulations for pulp and paper mill effluents and an industry shift away from elemental chlorine bleaching in the 1990s greatly reduced the release of polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/Fs) into the environment. However, the high potential of these contaminants to persist in sediment and bioaccumulate in biota means that they have remained a concern. To document ...
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Effect of temperature on streambed vertical hydraulic conductivity
In this study, in situ and on-site permeameter tests were conducted in Clear Creek, Nebraska, USA to evaluate the effect of water temperature on streambed vertical hydraulic conductivity Kv. Fifty-two sediment cores were tested. Five of them were transferred to the laboratory for a series of experiments to evaluate the effect of water temperature on Kv. Compared with in situ tests, 42 out of ...
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Internal phosphorus load in a mexican reservoir: Forecast and validation
To determine the internal phosphorus load (IPL) as a function of redox potential (Eh) in a Mexican reservoir, we extrapolate the results from a phosphorus (P) release experiment to temporal and spatial variations of Eh in sediments, obtaining an IPL‐Eh of 24.2 ± 2.5 t/yr. This result is compared to the P mass balance (MB) in the reservoir, where the IPL‐MB is determined as the difference ...
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Abundances, Depositional Fluxes, and Homologue Patterns of Polychlorinated Biphenyls in Dated Sediment Cores from the Pearl River Delta, China
Despite the recent efforts to investigate the distribution and fate of persistent organic pollutants in the tropical and subtropical regions of Asia, very little was known about the temporal change of polychlorinated biphenyls (PCBs) in the environmental ecosystem of China. In this study, three dated sediment cores collected from the Pearl River Delta of southern China were analyzed for a ...
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Horizontal and Vertical Distribution of Estrogenic Activities in Sediments and Waters from Tokyo Bay, Japan
Endocrine-disrupting chemicals with estrogenic activity (e.g., alkylphenols) have been detected in coastal Japan. We aimed to determine estrogenic activity in extracts of river water, seawater, sediments, and sediment cores from Tokyo Bay by in vitro gene expression assay. Fifty-one of 57 extracts had some estrogenic activity. E2 equivalents (ng E2 equivalents per gram dry weight or per liter ...
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Deconstruction of Historic Mercury Accumulation in Lake Sediments, Northeastern United States
Total atmospheric contribution of mercury (HgT) to lake sediment was estimated using 210Pb-dated sediment cores. Algorithms based on estimates of lake and watershed processes were applied to more accurately assess anthropogenic contributions of Hg to the environment and HgT. Factors addressed include: lake-specific background accumulation rates of Hg (HgB), variability of sediment accumulation ...
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Polychlorinated dibenzo
-p- dioxins and polychlorinated dibenzofuran concentrations in Xingyun Lake sediment close to the pulp mill region of Jiangchuan (China): a typical case studySediment cores from Xingyun Lake close to the pulp mill region of Jiangchuan (China), earlier found to be highly contaminated by pulping at least from the 1990s, were analyzed by HRGC/HRMS for the concentrations of 17 polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). Regarding the contribution of individual congeners, PCDD/F levels ranged from ND (non-detectable) to ...
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P distribution in different sediment fraction of a constructed wetland
The aim of this work was to study the accumulation and fractionation of P in the inlet and outlet sediment of a constructed wetland for the wastewater treatment of a metallurgic plant in Argentina. It was important to predict whether P could be released into the water again by changing environmental conditions or retained over time. P-fractionation was performed using a sequential extraction ...
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A 50-years record of dichloro-diphenyl-trichloroethanes and hexachloro-cyclohexanes in lake sediments and penguin droppings on King George Island, Maritime Antarctic
Since the ban on the use of organochlorine pesticides (OCPs) such as dichloro-diphenyl-trichloroethane (DDT) and hexachlorocyclohexane (HCH) in agriculture, their levels have generally dropped. In a number of cases, however, the levels of these OCPs were found to be unchanging or even increasing after the ban. With the aim to unveil the possible causes of these exceptions, we collected two lake ...
By IOS Press
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Soil Erosion Research - University of Zambia - Case Study
Description: A SediMeter was deployed in this water reservoir in order to collect data on the timing and amount of sedimentation in the water reservoir. Traditional methods include repeat measurements of the bed level, and taking of sediment cores, but they only allow the measurements of the net change between measurements, and are unable to register what exactly happens, and when it happens. In ...
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Subsurface movement of zinc from contaminated dredge spoils at a periodically flooded site
In 1982, sediments contaminated with zinc, cadmium, and copper were dredged from Lake DePue in Illinois and deposited in a diked sediment disposal area (DSDA) that is flooded annually for at least three months. Data from soil and groundwater samples collected at multiple depths within and adjacent to the DSDA indicate vertical movement of the metals in the subsurface, although groundwater outside ...
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High spatial resolution analysis of the distribution of sulfate reduction and sulfide oxidation in hypoxic sediment in a eutrophic estuary
Bottom hypoxia and consequential hydrogen sulfide (H2S) release from sediment in eutrophic estuaries is a major global environmental issue. We investigated dissolved oxygen, pH and H2S concentration profiles with microsensors and by sectioning sediment cores followed by colorimetric analysis. The results of these analyses were then compared with the physicochemical properties of the bottom ...
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Nitrogen removal in a shallow maturation pond with sludge accumulated during 10 years of operation in Brazil
Accumulated sludge in polishing (maturation) ponds reduces the hydraulic retention time (smaller useful volume), and this could potentially lead to a decrease in performance. However, settled biomass, present in the sediments, can contribute to nitrogen removal by different mechanisms such as nitrification and denitrification. This study investigated the influence of the bottom sludge present ...
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Denitrification of nitrogen released from senescing algal biomass in coastal agricultural headwater streams
Received for publication October 2, 2008. Assimilation of inorganic N by photoautotrophs has positive impacts on nutrient retention; however this retention is only temporary. As the biomass senesces, organic and inorganic forms of N are released back to the stream where they can be further transformed (i.e., nitrification, denitrification) or exported downstream. The purpose of this study was to ...
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Environmental fate of three novel brominated flame retardants in aquatic mesocosms
Currently, little is known about the environmental fate and persistence of novel brominated flame retardants (NBFRs). The recent detection of NBFRs in sediment cores and air samples provides insight into their persistence and potential for transport. Limited numbers of laboratory studies have examined the fate and behavior of these compounds, but field‐based fate studies have been especially ...
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