Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 36 for “"passive sampling"”.
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Analysis of volatile organic compounds (VOCs) in soil via passive sampling : measuring partition and diffusion coefficients
Passive sampling has been used as a qualitative and semi-quantitative method in detecting volatile organic compound (VOCs) concentrations in soil vapors or water. Passive sampling for soil vapor takes an absorptive material and places it underground for a period of time to allow the VOCs to diffuse …
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Using polyethylene passive sampling to assess transport of polychlorinated biphenyls (PCBs) between contaminated sediments, water, and biota
Polychlorinated biphenyls (PCBs), which were a widely used group of chemicals before their manufacture was banned in 1979 in the United States, still contaminate numerous aquatic systems. Although there are ongoing efforts to remediate these sites, our ability to implement effective remediation …
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Quantitative analysis of volatile organic compounds (VOCs) in soil via passive sampling : polyethylene sampler design and optimization
… still limited. A polyethylene (PE) quantitative passive sampler using performance reference compounds and deployed via a hand driven probe is proposed as a solution. Additionally, a 1D diffusion mass transfer model was developed in MATLAB to predict the mass uptake into the PE sampler over time. …
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Evaluating the combined use of three-dimensional hydrodynamic modeling and polyethylene passive sampling in the Lower Duwamish Waterway
Polyethylene (PE) passive samplers are capable of measuring in-situ, freely dissolved, time-averaged concentration distributions of contaminants in air, surface water, and sediment bed porewater. This sampling technique can be coupled with a three dimensional (3D) hydrodynamic model of a given …
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Benchtop testing of polyethylene passive sampling towards a quantitative analysis of volatile organic compounds (VOCs) in soil vapours
The feasibility of polyethylene (PE) as a passive sampler for quantitative analysis of volatile organic compounds (VOCs) was analysed in this work by means of a benchtop testing. A benchtop physical model was setup, which consisted of a jar of glass beads or sand, containing a known mass of toluene …
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Investigation Of The Use And Application Of Passive Sampling Methods For Understanding Potential Sources Of Mercury To Western United States
… scale. To address this, our study included sampling locations on the coast of California, in the Sierra Nevada Mountains and on the eastern edge of Nevada in the Great Basin spanning elevations of sea level up to ~2800 m. Surrogate surfaces and passive samplers were deployed across nine …
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Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)
… three applications of polyethylene (PE) passive sampling, which enhance our toolbox for estimating environmental hazards associated with HOCs. First, we present a methodology that can be used to estimate the bioaccumulation potential of numerous organic chemicals based on passive sampling …
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Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)
… three applications of polyethylene (PE) passive sampling, which enhance our toolbox for estimating environmental hazards associated with HOCs. First, we present a methodology that can be used to estimate the bioaccumulation potential of numerous organic chemicals based on passive sampling …
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Bioavailability of organic contaminants in sediments.
… affinity for particles and for traditional sampling (filtration and centrifugation) equipment. An equilibrium passive sampling device made of silicone rubber was developed in this research to measure the freely dissolved concentrations of lipophilic contaminants and other parameters (water …
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Passive detection of phosphorus in agricultural drainage waters using reactive hybrid anion exchange resins
… that are major contributors of P loss. A passive detection technique can be ideal for the monitoring of concentrations and loads of dissolved reactive P (DRP) from a large number of agricultural waterways because of its simplicity and cost effectiveness. The passive detection technique …
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Polyethylene passive samplers for measuring hydrophobic organic chemical concentrations in sediment porewaters and their use in predicting bioaccumulation in soft-shell clams (Mya arenaria) from sites near Boston, MA
… (1) the use of polyethylene (PE) sheets as passive sampling devices in sediments, using performance reference compounds (PRCs) in order to reduce deployment times to the order of days, (2) the use of limited PRC data to calibrate mass-transfer models for the exchange of a suite of compounds …
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Occurrence and fate of endocrine disrupting chemicals and other hydrophobic organic compounds in a tropical river in Kenya
This thesis explores the application of passive sampling as a novel monitoring technique capable of quantifying aquatic pollutants at low environmental concentrations, and in a form that is directly applicable to risk assessment. Two passive samplers, namely polyethersulfone (PES) and silicone …
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Application of diffusive gradient in thin-film passive samplers to assess mercury availability and mobility in a fresh water river system
… porewater is a challenge using conventional sampling techniques which commonly require removal of sediment, transportation, and processing. Passive sampling is an alternative technique that measures sediment porewater concentrations in-situ and without significant sample disturbance. One …
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Are PCBS in phytoplankton and zooplankton at equilibrium with the water in which they live?
… MA, were measured using polyethylene (PE) passive sampling strips, thereby avoiding problems associated with colloid-bound PCBs. Phytoplankton and zooplankton samples were measured to determine their PCB levels and lipid fractions. The phytoplankton were at equilibrium in the fall of 2016. …
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Pharmaceutical occurrence, distribution and degradation in rural wastewaters and surface waters in Scotland
… Dee (Aberdeenshire) over 12 months using both passive and grab sampling. Eight common pharmaceutical compounds were selected for this work: paracetamol, diclofenac and ibuprofen (analgesics/nonsteroidal anti-inflammatory drugs); clarithromycin and trimethoprim (antibiotics); carbamazepine and …
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Demonstrating the feasibility of polyethylene passive samplers for quantitative assessment of volatile organic compounds in soil
… by the successful use of polyethylene (PE) passive samplers in sediments, this research focused on demonstrating the feasibility of PE samplers to accurately assess volatile organic compounds in soil vapors. Experimental values of PE-water partitioning coefficients (Kpew) for benzene, …
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A method for using polyethylene passive samplers to measure polycyclic aromatic hydrocarbon chemical activity in sediments
… for the use of polyethylene (PE) sheets as passive sampling devices for measuring chemical activities was explored. A model which depends on a concentration gradient and two mass transfer limiting zones in series was used. Internal tracer chemicals within the polyethylene devices (PEDs) were …
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Combined effects of bioavailable organic contaminants in the aquatic environment.
In contrast to conventional spot or bottle water sampling techniques, passive sampling has been shown to be a reliable and efficient method for monitoring the toxicologically-relevant, freely-dissolved (e.g. bioavaialable) concentrations of a wide range of organic contaminants in water. At the same …
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Understanding of pesticides in waters and soils using a novel in situ dynamic sampling technique
… in the environment. Over the last few decades passive sampling approaches have aroused attention in detecting pesticides, but they are still under development. In this thesis, the passive sampling technique of diffusive gradients in thin-films (DGT) was developed and validated for pesticides in …
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