Abstract:h i g h l i g h t sKingston coal ash increases magnetic susceptibility of riverbed sediment. Fluvial transport both enriches and dilutes the magnetic fraction of coal ash. Micron-size magnetite and maghemite occur within aluminosilicate spheres. Magnetospheres dominate the magnetic signal in the Watts Bar watershed.
a b s t r a c tThe magnetic properties of riverbed samples collected after the 2008 Tennessee Valley Authority (TVA) coal ash spill in Kingston, Tennessee are investigated. Coal ash persists in thi… Show more
“…H CR /H C values for sediment with [ 13-14% ash range from 1.13 to 2.61 with an average of 1.81. These are similar to the hysteresis parameters observed for Kingston Fossil Plant coal ash (Cowan et al 2015). In contrast, diabase dikes have M R /M S values between 0.22 and 0.45 (McEnroe and Brown 2000), allowing a means to identify samples for which sediment derived from dikes could interfere with the use of v LF in coal ash detection.…”
Section: Rock-magnetic Characterizationsupporting
confidence: 75%
“…In the Watts Bar Reservoir System impacted by the TVA spill we used the mass-normalized low field magnetic susceptibility (v LF ) of riverbed samples to measure the coal ash content. This rapid, efficient and inexpensive method predicted ash concentrations greater than 15% (Cowan et al 2013(Cowan et al , 2015.…”
Section: Introductionmentioning
confidence: 99%
“…The effectiveness of using magnetic susceptibility to quantify ash mixed with Dan River sediment is tested. Previously, we used magnetic susceptibility as an analytical tool to quantify ash from the Tennessee Valley Authority (TVA) spill at the Kingston Fossil Plant (Cowan et al 2013(Cowan et al , 2015. In 2008, coal ash slurry spilled directly from an ash storage cell into the Emory River and after these deposits were scoured, suspended and mixed with river sediment the concentration of ash could not be visually quantified.…”
Section: Introductionmentioning
confidence: 99%
“…Oxidation of pyrite (FeS 2 ) in pulverized coal at high temperature produces molten iron spheres and sulfur, and the iron oxidizes to form magnetite and hematite (Flanders 1994). Ash from the failed TVA storage cell had a relatively low weight percent magnetic fraction (MF) of 1.4%, which was composed of predominately magnetite and maghemite (Cowan et al 2013(Cowan et al , 2015. However, even a small amount of ferrimagnetic material was sufficient to impart a strong contrast in v LF compared with the paramagnetic or diamagnetic sediments derived from sedimentary rocks in the Emory and Clinch River watershed (Cowan et al 2013).…”
A study of near surface sediments from the Dan River (southeastern USA) was conducted to assess the use of magnetic properties as proxies of coal ash after a recent spill. The watershed geology is diverse and potentially contributes magnetic minerals to riverbed sediment from diabase dikes in the Dan River Triassic Basin and from granitic gneiss outside the basin. Coal ash is heterogeneous, including aluminosilicate spheres, amorphous particles and carbonaceous rods and lacy particles. The magnetic fraction of ash from the failed storage pond is up to 17 wt% and is mostly composed of black spheres with maghemite and magnetite. Ash was detected in riverbed sediment from quiet water settings such as inside of meander bends, the confluence of tributary streams and near islands between the spill site and 20 miles downstream in the Schoolfield Reservoir, Danville, VA. The strong magnetic signal is detected above background in riverbed samples and is strongly positively correlated with total ash; elevated low field magnetic susceptibility (χ LF) is evident in samples with ≥ 12% ash content. Anhysteretic remanent magnetization and hysteresis parameters delineate native sediment, ash-bearing sediment, and diabase dikes. Between 20 and 70 miles downstream of the spill site, ash concentrations were either buried or too low due to dilution with native sediment to be detected with χ LF in riverbed samples. Cowan, E.A., Epperson, E.E., Seramur, K.C. et al. Magnetic susceptibility as a proxy for coal ash pollution within riverbed sediments in a watershed with complex geology (southeastern USA).
“…H CR /H C values for sediment with [ 13-14% ash range from 1.13 to 2.61 with an average of 1.81. These are similar to the hysteresis parameters observed for Kingston Fossil Plant coal ash (Cowan et al 2015). In contrast, diabase dikes have M R /M S values between 0.22 and 0.45 (McEnroe and Brown 2000), allowing a means to identify samples for which sediment derived from dikes could interfere with the use of v LF in coal ash detection.…”
Section: Rock-magnetic Characterizationsupporting
confidence: 75%
“…In the Watts Bar Reservoir System impacted by the TVA spill we used the mass-normalized low field magnetic susceptibility (v LF ) of riverbed samples to measure the coal ash content. This rapid, efficient and inexpensive method predicted ash concentrations greater than 15% (Cowan et al 2013(Cowan et al , 2015.…”
Section: Introductionmentioning
confidence: 99%
“…The effectiveness of using magnetic susceptibility to quantify ash mixed with Dan River sediment is tested. Previously, we used magnetic susceptibility as an analytical tool to quantify ash from the Tennessee Valley Authority (TVA) spill at the Kingston Fossil Plant (Cowan et al 2013(Cowan et al , 2015. In 2008, coal ash slurry spilled directly from an ash storage cell into the Emory River and after these deposits were scoured, suspended and mixed with river sediment the concentration of ash could not be visually quantified.…”
Section: Introductionmentioning
confidence: 99%
“…Oxidation of pyrite (FeS 2 ) in pulverized coal at high temperature produces molten iron spheres and sulfur, and the iron oxidizes to form magnetite and hematite (Flanders 1994). Ash from the failed TVA storage cell had a relatively low weight percent magnetic fraction (MF) of 1.4%, which was composed of predominately magnetite and maghemite (Cowan et al 2013(Cowan et al , 2015. However, even a small amount of ferrimagnetic material was sufficient to impart a strong contrast in v LF compared with the paramagnetic or diamagnetic sediments derived from sedimentary rocks in the Emory and Clinch River watershed (Cowan et al 2013).…”
A study of near surface sediments from the Dan River (southeastern USA) was conducted to assess the use of magnetic properties as proxies of coal ash after a recent spill. The watershed geology is diverse and potentially contributes magnetic minerals to riverbed sediment from diabase dikes in the Dan River Triassic Basin and from granitic gneiss outside the basin. Coal ash is heterogeneous, including aluminosilicate spheres, amorphous particles and carbonaceous rods and lacy particles. The magnetic fraction of ash from the failed storage pond is up to 17 wt% and is mostly composed of black spheres with maghemite and magnetite. Ash was detected in riverbed sediment from quiet water settings such as inside of meander bends, the confluence of tributary streams and near islands between the spill site and 20 miles downstream in the Schoolfield Reservoir, Danville, VA. The strong magnetic signal is detected above background in riverbed samples and is strongly positively correlated with total ash; elevated low field magnetic susceptibility (χ LF) is evident in samples with ≥ 12% ash content. Anhysteretic remanent magnetization and hysteresis parameters delineate native sediment, ash-bearing sediment, and diabase dikes. Between 20 and 70 miles downstream of the spill site, ash concentrations were either buried or too low due to dilution with native sediment to be detected with χ LF in riverbed samples. Cowan, E.A., Epperson, E.E., Seramur, K.C. et al. Magnetic susceptibility as a proxy for coal ash pollution within riverbed sediments in a watershed with complex geology (southeastern USA).
“…Magnetometry is also applied for tracing the transport of pollutants along the river by observing the migration of the strongly magnetic spherical-shaped particles (spherules) associated with heavy metals, which commonly originate from urban activities (power plants, smelting industries, disposal sites, municipal wastes) (Cowan et al 2015;Desenfant et al 2004;Li et al 2011;Zhang et al 2011). Changes in concentration-dependent magnetic parameters along core sediments can adequately reveal the distribution of river pollution over time.…”
The present study evaluated the level of heavy metal (HM) pollution in Vistula river sediments in a highly urbanized Warsaw agglomeration (Poland). Magnetometry was used to assess the pollution level by measuring the fine fractions (0.071 mm and < 0.071 mm) of sediments collected from the surface layer of the riverbank. The magnetic methods (e.g., mass magnetic susceptibility χ, temperature-dependence magnetic susceptibility, and hysteresis loop parameters) were supplemented by microscopy observations and chemical element analyses. The results showed the local impact of Warsaw's activity on the level of HM pollution, indicated by the maximum concentrations of magnetic particles and HM in the city center. The sediment fraction < 0.071 mm was dominated by magnetite and by a large amount of spherical-shaped anthropogenic magnetic particles. The pollution from the center of Warsaw was transported down-river over a relatively short distance of approximately 11 km. There was a gradual decrease in the concentrations of magnetic particles and HM in areas located to the north of the city center (down-river); furthermore, χ and concentrations of HM did not decrease to the values observed for the area to the south of Warsaw (up-river). The study showed two possible sources of sediment pollution: traffic-related and heat and power plant emissions. The influence of an additional source of pollution cannot be excluded as the amount of spherules in the sediments at the center was extremely high. The present study demonstrates that magnetometry has a practical application in detecting and mapping HM pollution in river systems.
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